Contributions to Terrestrial Magnetism.--No. IX

Magnetic Declination in the Atlantic Ocean between the Equator and 60° North Latitude, for January 1840. by Lieut. Colonel Edward Sabine, R.A. Forth Sec'y R.S. East Declin. has the sign - prefixed. Magnetic Declination in the Atlantic Ocean between the Equator and 60° South Latitude for January 1840. by Lieut. Colonel Edward Sabine R.A. For. Sec'y R.S. East Declin. has the Sign - prefixed. SOUTH AMERICA XII. Contributions to Terrestrial Magnetism.—No. IX. By Lieut.-Colonel Edward Sabine, R.A., For. Sec. R.S. Received May 24,—Read June 21, 1849. Containing a Map of the Magnetic Declination for 1840 in the Atlantic Ocean between the parallels of 60° North and 60° South Latitude. In compliance with repeated representations from the Hydrographer of the Admiralty, that a correct map of the magnetic Declination over the Atlantic Ocean corresponding to the present epoch was most urgently required for the purposes of navigation, I have deemed it proper,—partly on account of the importance of the object itself, and partly in acknowledgement of the claim which the practical wants of those who traverse the seas have on that physical science which they so much contribute to advance,—to suspend the progress of the publication of the observations made at the colonial magnetical and meteorological observatories, until in compliance with the wishes of the Admiralty a Declination map of the Atlantic has been completed. I have endeavoured at the same time so to conduct and arrange the preliminary investigation, that it may form a fitting part of the magnetic survey of the globe, which is designed to be comprehended in the series of Magnetic Contributions, of which the first eight numbers have been honoured with a place in the Philosophical Transactions. The limits which have been taken for the map, in respect to latitude, are the parallels of 60° north and 60° south. The number of distinct determinations within those limits, either at sea or on adjacent coasts or islands, which have been reduced and coordinated, amounts to 1480. Each determination is, in the majority of cases, a mean result of several distinct and independent observations. They are all comprised between the beginning of 1828 and the end of 1848; the commencement of 1840 being taken as the epoch of the map; and each determination being reduced to that epoch by the rate of secular change derived by comparison with the map of MDCCCXLIX. the Declination in 1787, published by M. Hansteen in his great work, Magnetismus der Erde, and republished by myself in this country in the Reports of the British Association for the Advancement of Science for 1834. Of the determinations made at sea, all have been corrected for the effect of the ship's iron when observations on which the corrections must depend have been provided. I have discussed those corrections in more detail and at greater length than I might otherwise have done, on account of the practical importance attaching to this part of the subject since the introduction of steam navigation and the increased employment of iron in the construction and equipment of vessels; and in the hope and belief that the discussion may be found to have a practical as well as a theoretical value. The 1480 determinations reduced and corrected for epoch are arranged in a general Table in Zones, each zone including $10^\circ$ of latitude; the determinations comprised in each zone are arranged in the order of their longitudes, commencing always with the most westerly: they are all likewise inserted in the map, where they are expressed in degrees and decimals of a degree. For the purpose of drawing the lines of declination in general conformity with the determinations, the latter have been arranged in groups, each group having its mean geographical position at or near the point of intersection of every fifth meridian and parallel, (as far as the observations would permit,) counting from the parallel of $0^\circ$, and the meridian of $280^\circ$; and in the more frequented parts, and where consequently the number of determinations was greatest, at or near the points of intersection of parallels and meridians distant only $2\frac{1}{2}$ degrees from each other. Each group contains all the determinations comprised within equal distances of latitude and equal distances of longitude on either side of the point of intersection; the distances being so taken that the number of determinations constituting a group should be generally from ten to twenty. If the mean geographical position corresponding to the determinations in a group differed more than a few minutes from the latitude or longitude of the desired point of intersection, one or two determinations adjacent to, but beyond the limit, were taken into the group, or one or two pairs of determinations within the limits were combined and their mean taken instead of the separate results. This was done for the purpose of diminishing the amount of the correction to be applied to the mean declination of the group, to reduce it to the corresponding value of the declination at the point of intersection itself. The factors employed in making that reduction were derived from the map itself. The values of the declination thus obtained at the intersection of every fifth degree of latitude and longitude (as far as the determinations permitted), and at the intersection of every $2\frac{1}{2}$ degrees in the more frequented quarters, have been regarded as elements of the declination lines; and these lines have been drawn in accordance with the elements with only such slight deviations as were indispensable to preserve an interconformity between the lines, where it was evident that the determinations themselves were slightly discordant. The values of the Declination at the points of intersection obtained by the process of grouping are collected in Table VIII., and are also exhibited in the Map in larger and more conspicuous figures than those which represent the determinations from which they are severally derived. The map thus contains, first, the original determinations reduced to the mean epoch; secondly, the elements, or mean values for the points of intersection, derived from the determinations; and thirdly, the lines themselves derived from the elements, so that the degree of accordance of the elements and of the lines with the sources from whence they are derived may be everywhere judged of by inspection. The determinations employed in this Memoir have been obtained from the following sources: (A.) Sea observations uncorrected for the effects of the Ship's Iron. 1. Observations made in the corvette Krotkoi by Dr. Adolph Erman in her homeward voyage from Cape Horn to Portsmouth in 1830; extracted from Erman's Reise um die Erde. 2. Observations made on board the Beagle, Captain Robert FitzRoy, on her outward passage from England to South America in 1831 and 1832, and whilst on the South American station, east of Cape Horn, in 1833 and 1834; and on her homeward passage in 1836 from the Cape of Good Hope to the British Channel; extracted from the published account of the voyage. 3. Observations made on board the corvette La Bonite, Captain Vaillant, on her outward passage from Toulon round Cape Horn in 1836, and on her homeward passage in 1837 from the Cape of Good Hope to Brest; extracted from the published account of the voyage. 4. Observations made on board the frigate La Venus, Captain (since Admiral) Du Petit-Thouars, in her outward passage from France round Cape Horn in 1837, and in her homeward passage in 1839 from the Cape of Good Hope to Brest; extracted from the published account of the voyage. 5. Observations made by Captain (since Admiral) Berard, on board the brig Le Voltigeur in a voyage in 1838 from Toulon to Vera Cruz, and from thence by New York to Brest; and on board the corvette Le Rhin, on her outward passage from Toulon to the Cape of Good Hope in 1842, and in her homeward passage from Cape Horn by St. Helena to Toulon in 1846; from a MS. obligingly communicated to me by Captain Duperray, Membre de l'Institut. 6. Observations made on board La Prevoyante by Captain Jehenne, on a passage from the Cape of Good Hope by St. Helena to Cayenne in 1842; extracted from the Annales Maritimes et Coloniales for 1843. 7. Observations made in H.M.S. Curaçoa, Captain Sir Thomas Sabine Pasley, Bart., whilst on the South American station in 1843 and 1844; MSS. (B.) Sea observations corrected for the effects of the Ship's Iron. 8. Observations made on board H.M.S. Erebus, Captain Sir James Clark Ross, in her outward passage from England to St. Helena and the Cape of Good Hope in 1839 and 1840; MSS. 9. Observations made on board H.M.S. Thunder, Captain Edward Barnett, in a passage from the Bahama Islands to the British Channel in 1841; MSS. 10. Observations made on board H.M. Ships Erebus and Terror, Captains Sir James Clark Ross and F. R. M. Crozier, in the (Antarctic) summer of 1842–1843, between Cape Horn and the Cape of Good Hope; MSS. 11. Observations made on board the Prince Regent transport, by Captain John Henry Lefroy, R.A., in a passage from England to Quebec in 1842; MSS. 12. Observations made in H.M. hired bark Pagoda, by Lieut. (since Commander) T. E. L. Moore, R.N., and Lieut. (since Captain) Henry Clerk, R.A., in a voyage from the Cape of Good Hope to the Antarctic Circle in 1845; extracted from the Philosophical Transactions for 1847. 13. Observations made on board H.M.S. Philomel, Captain Bartholomew J. Sullivan, in a passage from Monte Video to the British Channel in 1846; MSS. 14. Observations made on board the Hudson's Bay Company ship Prince Albert, by Lieut. (since Commander) T. E. L. Moore, in a voyage from England to Moose Fort in Hudson’s Bay and back, in 1846; MSS. 15. Observations made on board H.M.S. Rattlesnake, Captain Owen Stanley, in her outward passage from the British Channel to the Cape of Good Hope in 1846 and 1847; MSS. (C.) Land observations on the coasts and islands of the Atlantic. 16. Observations at several points of the South American coast and of the Falkland Islands in 1832, 1833 and 1834, by Captain Robert FitzRoy, R.N.; extracted from the Voyage of the Beagle. 17. Observations at several points of the Falkland Islands and on the South American coast and its vicinity, between 1843 and 1846, by Captain Bartholomew J. Sullivan, R.N.; MSS. 18. Observations during the voyage of the Chanticleer, between 1828 and 1831 at several stations on the coast of the Atlantic, by Captain Henry Foster and Captain Horatio Austin, R.N.; MSS. 19. Observations at various points of the coasts adjacent to the Gulf and River St. Lawrence in the years 1828 to 1848, by Captain H. W. Bayfield, R.N.; MSS. 20. Observations on several points of the Feroe and Shetland Islands and of the Hebrides in 1831, and on the West Coast of Africa in 1836 and 1838, and in the Western Islands in 1843 and 1844, by Captain A. Vidal, R.N.; MSS. 21. Observations made at several stations on the islands and coasts of the Atlantic and Caribbean Sea, from 1837 to 1840, by Captain A. Milne, R.N. 22. Observations at several stations in Guiana in 1842 and 1843, by Sir Robert Schomburgk, employed as Boundary Commissioner; MSS. 23. Observations at several stations in the vicinity of the River St. Lawrence in 1842, by Captain J. H. Lefroy, R.A.; MSS. 24. Observations at several stations in the British Islands in 1838, by Captain Sir James Clark Ross, R.N.; MSS. 25. Observations (with a transportable Declinometer) at stations on the North Coast of Scotland, by Commander H. C. Otter, R.N.; MSS. 26. Observations at several points of the coast of Western Africa in 1845 and 1846, by Captain H. M. Denham, R.N.; MSS. 27. Observations at several stations on the coast of the United States of America in the years 1844 to 1846, in the progress of the United States Coast Survey; extracted from the published Charts of the Survey. 28. Observations (with a transportable Declinometer) in 1848 at stations in the Gulf of St. Lawrence, by Dr. Kelly, R.N.; MSS. 29. Declinations determined at the observatories of Algiers, Brussels, Cape of Good Hope, Christiania, Dublin, Greenwich, Makerstoun, Paris, St. Helena, and Toronto in Canada; extracted from official sources: and at Rio Janeiro by Herr von Helmreich in 1845 with a transportable Magnetometer; MSS. 30. Declinations observed by Lieut.-Colonel Graham of the United States Topographical Engineers, and by other officers of that corps, and surveyors employed under his direction in the Commission for determining the boundary between the United States and the British Possessions in North America. I am indebted to the liberality and kindness of Lieut.-Colonel Graham for the communication of the manuscript of these valuable observations, which connect the determinations of Captains Bayfield, R.N., and Lefroy, R.A. in Canada, with those of the United States Coast Survey in New York and the more southern states. Correction of the observations in Schedule (B.) for the effects of the Ship's Iron. Observations in H.M.S. Erebus on her passage from England to St. Helena and the Cape of Good Hope. When commenting in the Fifth Number of the Magnetic Contributions upon a portion of the magnetic observations of the two first years of Sir James Ross's Antarctic Expedition, which were all that at that time had reached England, I remarked that their examination had led me to the opinion, that the disturbances of the compass in the Erebus and Terror exhibited a character distinct from any which had been previously recognised, either in theoretical discussions or in practical applications. In all the investigations with which I was acquainted, in which the disturbing influence of a ship's magnetism upon her compass had been considered, and in all the remedies which had been suggested, either by the employment of counteracting forces, or by corrections to be applied to the indications of a compass where no such artificial counteractions were employed, the magnetism of the ship had been regarded either as wholly induced by the magnetic action of the earth and as varying simultaneously with variations in the inducing cause, or as partly due to induction, and partly to the *permanent* magnetism of certain portions of the ship's iron; in which latter case the part of the disturbance occasioned by induction was considered to be variable in the manner already described; and the part occasioned by the permanent magnetism to be constant, or nearly so. Upon the hypothesis of the whole disturbance being occasioned by induced magnetism, its amount in any particular direction of the ship's head should be the same, or nearly so, in north and south dips of equal amount, but should have opposite signs; that is to say, the disturbance which was towards the west when the north end of the needle dipped, should be towards the east when the south end of the needle dipped, and should be to the same amount: and if the further assumption were correct, that the induced magnetism of the ship changed simultaneously with changes in the terrestrial dip, as is known to be the case with soft iron, the disturbance might be altogether (at least approximately) prevented, by a counteracting mass of soft iron disposed suitably in reference to the place of the compass and to the resultant of the ship's magnetic action. On the supposition that the disturbances were due partly to the induced magnetism of certain portions of a ship's iron, and partly to the permanent magnetism of other portions, the calculation of corrections would become more complex, as terms must be introduced to represent both a variable and a constant effect; and counteraction by means of soft iron would no longer meet the case. But a combination of permanent magnets and of soft iron, each suitably disposed, might, as was supposed, accomplish and preserve an approximate compensation, if the magnets and the permanently magnetic portion of the ship's iron maintained their magnetic relations unaltered, and if the changes of the induced magnetism of the ship were as simultaneous with changes in the terrestrial magnetism as they were presumed to be in soft iron. The observations which were made on the disturbance of the compass needle of the Erebus and Terror in the river Thames, where the magnetic dip was about $69^\circ$ north, and at Hobarton, where the dip was between $70^\circ$ and $71^\circ$ south (the ships in both cases having remained several months in the localities of the respective dips), showed that in the interval between the two sets of observations a change had taken place in the disturbance, corresponding in kind, and almost precisely in degree, with the hypothesis of induced magnetism. The disturbance was in the opposite direction at Hobarton to what it had been in the Thames: in the one case the north pole of the compass needle was drawn towards the fore part of the ship, and in the other case the south pole. The amount of disturbance in the one direction in the Thames, and in the opposite direction at Hobarton, was so nearly the same—the terrestrial dip having also nearly the same numerical value at the two stations, but with opposite signs,—as fully to bear out the inference, that in those two ships the chief part if not the whole of the disturbance of the compass was occasioned by induced magnetism. Such being the case, it might naturally have been expected that formulæ founded on M. Poisson's investigations regarding the induced magnetism of ships, which represented so well the change that had taken place between England and Van Diemen Island, would also represent the disturbance which had been found to take place at stations visited by the ships in the intermediate passage; and that the result of azimuths observed in the same geographical position of the ship, with her head on different points of the compass, would be brought into agreement with each other, at any period of the voyage, by corrections computed by the formulæ of which the variable coefficients were taken as varying with the changes of the terrestrial dip. Such however was by no means the case. A table of corrections was computed by the appropriate formulæ for each of the thirty-two points and for every degree of north and south dip; the values of the coefficients in the formulæ being derived from the observations in the Thames and at Hobarton; and those which were variable being assumed, in conformity with the hypothesis, to vary according to the dip. On comparing this table with the observations at intermediate times and stations, it was immediately perceived that in order to suit the table to the observations, it was necessary to enter the table, not with the dip at the time and place of the observation to be corrected, but with a dip which had been passed through by the ship several days antecedently; and on a more close and general examination, this was found to be the systematic and consistent result of the whole comparison. This result by no means contradicts the inference previously drawn, and based on the observations in the Thames and at Hobarton, viz. that the disturbances in the Erebus and Terror were chiefly if not wholly ascribable to induced magnetism; for it is quite conceivable that portions of a ship's iron, which are not permanently magnetic on the one hand, nor perfectly soft so as to undergo instantaneous change with changes of the dip on the other hand, may still derive magnetism by induction from the earth, which may conform gradually rather than instantaneously to the changes of terrestrial magnetism corresponding to changes of the ship's place; so that after an interval of greater or less duration, the variation of the magnetic state which is characteristic of induced magnetism may be as complete in such portions of the iron as in those in which the change takes place instantaneously: but it is inconsistent with the proposed counteraction of the induced portion of the disturbance by means of soft iron, unless a degree of retentive force could be given to the soft iron which should be precisely equivalent to that of the general resultant of all the iron in a ship which is not permanently magnetic; and which doubtless varies considerably in different ships. Since 1843, when the fifth number of the Magnetic contributions was printed, I have examined the observations made in several ships which have passed from one hemisphere to the other, and have found them, without a single exception, cor- responding in character to those of the Erebus and Terror. When a ship is rapidly changing her geographical position, or when she has just arrived in port after making a recent considerable change of geographical position, her magnetism is always in arrear (if I may so express myself) of the change which would be equivalent to the change in the terrestrial dip; but after she has remained in the same locality a period, which may be supposed to depend in some measure on the rapidity and amount of the change of dip that she has passed through, as well as on the particular degree of retentiveness of her iron, I have found in all cases that have hitherto come under my examination, that the amount of disturbance in north and south dips of equal amount becomes ultimately the same, but with the opposite sign. The practical bearing of these conclusions is considerable. If the whole disturbance be due to induced magnetism,—and if when changes of geographical position are made, the disturbance is found to conform fully to the laws of induced magnetism after an interval which may be considered brief in comparison with a ship's frequent detention in different places, whilst during that interval it is in continual progress thereto,—permanent magnets are wholly inappropriate for the purpose of supplying a compensating force in ships making considerable changes of geographical position; and if correctly applied in the one hemisphere they may even double the error they were intended to correct when the ship is in the other hemisphere. On the other hand, the compensation by means of soft iron, if correctly applied in the one hemisphere, may become after a time an equally approximate compensation in the other hemisphere; but in the passage from the one hemisphere to the other, and generally when a ship is changing rapidly her geographical locality, the compensation may be very imperfect; and errors thus resulting are the more likely to be prejudicial when a compass is supposed to be compensated, because the habit of watching for them is then impaired. The counteraction of the disturbance by the introduction of a magnetic force which should at all times counterbalance that of the ship, would seem therefore to be a more complicated problem than it has been supposed to be: for neither permanent magnets, nor iron which changes simultaneously, can afford separately or conjointly suitable compensation for disturbances which are in part at least a function of time. Nor are these conclusions without a practical bearing on the applicabilities of the formulæ which have been derived from theoretical investigations, for the purpose of supplying corrections for the disturbing influence of a ship's iron on her compass, and on other magnetical instruments employed on board ship: for it becomes necessary to take into account, in addition to the two qualities of iron previously recognised and for which terms were provided, a third portion which is of an intermediate quality between the other two, and of which the magnetism is neither permanent on the one hand, nor are its changes simultaneous with or immediately consequent on changes of the terrestrial dip. Even in the most simple case of the disturbances being occasioned chiefly or wholly by induced magnetism, the data which are furnished by swinging a ship in harbour, even if repeated in more than one locality, must be insufficient to furnish corrections for the observations which may be made at sea in passages from port to port, if unaccompanied by experimental data furnished from time to time during the passages themselves. Seeing therefore the importance of the conclusions to which I have been led, I have thought it desirable to collect together in one point of view on the present occasion all the observations which were made in the Erebus for the purpose of examining the disturbance of the compass, during the three years in which she was employed in the Antarctic Expedition, and to enter on a somewhat detailed discussion of them. **Table I.—Disturbance of the Compass in H.M.S. Erebus.** + Implies a disturbance of the North end of the needle towards the West; — towards the East. | Direction of ship's head. | Gillingham, September 1839. | Port Praya, November 1839. | St. Helena, February 1840. | Cape of Good Hope, April 1840. | Kerguelen Island, July 1840. | Hobarton, October 1840. | Hobarton, June 1841. | Falkland Islands, August 1842. | Cape of Good Hope, April 1843. | |--------------------------|---------------------------|---------------------------|---------------------------|-----------------------------|-------------------------|------------------------|------------------------|--------------------------|------------------------| | N. by w. | +1° 12' | +0° 27' | −0° 02' | +0° 16' | −0° 27' | −0° 35' | −1° 28' | −0° 04' | −0° 37' | | N.N.W. | +2° 01' | +0° 20' | −0° 27' | +0° 10' | −1° 08' | −0° 29' | −2° 15' | −0° 34' | −1° 04' | | N.W. by n. | +2° 10' | +0° 52' | −0° 34' | +0° 02' | −2° 07' | −1° 43' | −2° 48' | −0° 51' | −1° 15' | | N.W. | +3° 03' | +1° 15' | −0° 40' | −0° 03' | −2° 02' | −1° 59' | −3° 09' | −1° 02' | −1° 42' | | N.W. by w. | +3° 28' | +1° 25' | −1° 03' | −0° 15' | −2° 27' | −2° 47' | −3° 27' | −1° 01' | −2° 01' | | W.N.W. | +3° 51' | +1° 05' | −0° 25' | −0° 33' | −3° 12' | −3° 07' | −4° 04' | −1° 49' | −2° 35' | | W. by n. | +4° 09' | +1° 15' | −0° 29' | −0° 51' | −3° 36' | −3° 37' | −4° 47' | −2° 10' | −2° 54' | | W. | +4° 19' | +1° 33' | −0° 32' | −1° 09' | −3° 41' | −4° 03' | −5° 13' | −2° 16' | −3° 69' | | W. by s. | +4° 40' | +1° 49' | −0° 12' | −1° 14' | −3° 56' | −4° 02' | −5° 11' | −2° 21' | −3° 17' | | W.S.W. | +4° 03' | +1° 24' | −0° 09' | −1° 05' | −4° 06' | −4° 16' | −4° 55' | −2° 21' | −3° 09' | | S.W. by w. | +3° 24' | +1° 34' | +0° 08' | −1° 06' | −3° 47' | −4° 27' | −4° 33' | −2° 14' | −2° 52' | | S.W. | +2° 45' | +0° 26' | +0° 04' | −0° 52' | −3° 23' | −3° 55' | −3° 54' | −1° 58' | −2° 27' | | S.W. by s. | +2° 08' | +0° 09' | +0° 14' | −0° 40' | −2° 34' | −3° 24' | −3° 13' | −1° 43' | −1° 52' | | S.S.W. | +1° 34' | −0° 02' | −0° 01' | −0° 02' | −1° 53' | −2° 18' | −2° 30' | −1° 17' | −1° 12' | | S. by w. | +0° 52' | +0° 10' | −0° 09' | +0° 16' | −0° 45' | −1° 27' | −0° 34' | −0° 39' | −0° 07' | | S. | +0° 28' | −0° 39' | −0° 29' | +0° 39' | +0° 22' | −0° 38' | +0° 29' | 0° 00' | +0° 33' | | S. by e. | −0° 19' | −0° 32' | −0° 24' | +1° 14' | +1° 10' | +0° 21' | +2° 18' | +0° 44' | +1° 07' | | S.S.E. | −0° 48' | −0° 42' | −0° 30' | +1° 26' | +2° 05' | +0° 39' | +2° 52' | +1° 13' | +1° 45' | | S.E. by s. | −1° 23' | −0° 25' | −0° 25' | +1° 41' | +2° 50' | +1° 24' | +3° 37' | +1° 41' | +2° 08' | | S.E. | −1° 53' | −1° 09' | −0° 21' | +2° 53' | +3° 21' | +1° 56' | +4° 20' | +1° 55' | +2° 31' | | S.E. by e. | −2° 21' | −1° 25' | −0° 21' | +2° 01' | +3° 51' | +1° 46' | +4° 46' | +2° 07' | +2° 51' | | E.S.E. | −2° 50' | −1° 18' | −0° 06' | +1° 43' | +4° 12' | +3° 29' | +5° 31' | +2° 19' | +3° 15' | | E. by s. | −3° 17' | −1° 44' | +0° 13' | +1° 34' | +3° 53' | +3° 23' | +5° 06' | +2° 16' | +3° 10' | | E. | −3° 42' | −1° 56' | +0° 32' | +1° 15' | +3° 48' | +3° 50' | +4° 53' | +2° 07' | +2° 46' | | E. by n. | −4° 53' | −2° 40' | +0° 55' | +1° 02' | +3° 31' | +4° 06' | +4° 32' | +1° 54' | +2° 30' | | E.N.E. | −3° 46' | −2° 47' | +0° 57' | +1° 51' | +3° 02' | +3° 41' | +3° 52' | +1° 44' | +2° 15' | | N.E. by e. | −3° 18' | −2° 30' | +0° 48' | +0° 31' | +2° 13' | +3° 33' | +3° 31' | +1° 16' | +1° 59' | | N.E. | −2° 59' | −2° 10' | +1° 11' | +0° 22' | +2° 10' | +3° 23' | +2° 54' | +0° 51' | +1° 33' | | N.E. by n. | −2° 16' | −2° 12' | +0° 52' | +0° 11' | +1° 32' | +3° 01' | +2° 25' | +0° 41' | +1° 15' | | N.N.E. | −1° 39' | −1° 53' | +0° 28' | +0° 01' | +1° 01' | +2° 37' | +1° 15' | +0° 41' | +0° 43' | | N. by e. | −0° 49' | −1° 17' | +0° 17' | +0° 24' | +0° 23' | +2° 17' | +0° 23' | +0° 28' | +0° 15' | | N. | +0° 06' | −0° 56' | +0° 05' | +0° 24' | −0° 08' | +1° 12' | +0° 41' | +0° 13' | −0° 20' | From the observations in September 1839, at Gillingham in the River Thames (where the ship had been stationary for many months), a table was formed by the well-known formulæ derived from Poisson’s fundamental equations applicable to in- duced magnetism, giving the corrections which, on that hypothesis, and on the further supposition that the changes in the induced magnetism of the ship were simultaneous with those of terrestrial magnetism, should have corresponded with the disturbance on each of the thirty-two points of the compass under every degree of the terrestrial dip. On examining, by means of this table, the number of degrees of dip by which it was necessary to go back from the dip at the place of observation, in order to obtain from the table corrections corresponding to the disturbances at the stations where the ship was subsequently swung, I find that at Port Praya, where the dip was $+45^\circ 32'$, and after a passage of thirty-six days from the British Channel, where the dip was about $+69^\circ$, that the ship's magnetism, instead of corresponding to a dip of $+45^\circ 32'$, did in fact correspond to a dip of about $+51^\circ \frac{1}{2}$; the arrear being about $6^\circ$. At St. Helena, where the dip was about $-20^\circ$, and where the ship had arrived after a passage of about seventy-nine days from Port Praya, during which she had passed from north into south dip, the arrear was between thirty and forty degrees—the tabular corrections for $20^\circ$ north dip corresponding more nearly with the differences of the azimuths observed at St. Helena with the ship's head on different points, than did the tabular corrections for $20^\circ$ south dip; so that the effect of the employment of the latter would manifestly have been to have increased the evil which they were intended to correct. At the Cape of Good Hope, where the dip was $-53^\circ$, and after an interval of thirty-eight days from her departure from St. Helena, the arrear appears to have been about twelve degrees. At Kerguelen Island, where the ship arrived after a passage of forty days from the Cape, but where she remained in harbour about fifty days before the disturbance experiments were made, the tabular corrections had overtaken the terrestrial dip, although the latter had increased from $-53^\circ$ at the Cape to $-70^\circ$ at Kerguelen Island; above one hundred days had elapsed between the experiments in $-53^\circ$ and those in $-70^\circ$ of dip, of which less than half the number were occupied in making the passage from the dip of $-53^\circ$ to that of $-70^\circ$, and the rest were passed at the anchorage in $-70^\circ$. From Kerguelen Island the Erebus proceeded to Hobarton, where the dip was the same, within a degree, as at Kerguelen Island, being $-70^\circ 40'$, and where, as I have already stated, the disturbances were found to be, both in kind and amount, very nearly such as might have been computed beforehand from the observations in the Thames, by the formulæ which apply to induced magnetism susceptible of instantaneous change, the tabular corrections compensating the disturbances within the limits of the usual errors of observation. From Hobarton the Erebus proceeded, in November 1840, to the high geographical latitudes of the southern hemisphere, and remained for some months in south dips much exceeding that at Hobarton, to which station she returned in April 1841. On the 29th of June 1841, being about eleven weeks after her arrival in harbour, observations were made on the disturbances of the compass on each of the thirty-two points. The arrear was now found to be on the side of the higher dips, though probably to a much less amount than might have been the case had the observations been made at an earlier period after her return; the tabular corrections which most nearly correspond to the observed disturbances are those of the dip $-71^\circ 28'$ instead of $-70^\circ 40'$. The expedition left Hobarton a second time in July 1841, passing the following (Antarctic) summer again in the regions of high southern dip, and returning to the Falkland Islands in April 1842, where the dip was between $-52^\circ$ and $-53^\circ$; the observations on the disturbances of the compass were made in August, being about four months after the ship arrived; an arrear however still remained on the side of the high dips in which several months had been passed previously to her arrival; the tabular corrections corresponding to the disturbances are those belonging to a dip of between $-56^\circ$ and $-57^\circ$, instead of between $-52^\circ$ and $-53^\circ$. From the Falkland Islands the Erebus sailed once more for the high latitudes in December 1842, returning, on this occasion, to the Cape of Good Hope in April 1843. She had now been in localities of higher southern dip than that of the Cape during nearly the whole of the three years which had elapsed since her former visit to the Cape, and she had passed the three months immediately antecedent to her second arrival, in dips varying from $-60^\circ$ to $-65^\circ$, that of the Cape at the same period being $-53^\circ 30'$. The disturbances of the compass were examined on the 20th of April, being a very few days after her arrival at the Cape, and I find that the tabular corrections corresponding to them are those belonging to a dip of about $-63^\circ 30'$. The arrear on this occasion was therefore about $10^\circ$ on the side of the higher dips, it having been about $12^\circ$ on the side of the lower dips when the ship arrived, in 1840, at the same station from localities of lower dip. The experiments at the Cape in April 1843 were the last, I understand, that were made in the Erebus during the progress of the voyage, for the purpose of examining the influence of the ship's iron on her compass by the usual process of swinging the ship: and by an unfortunate misunderstanding, the repetition of the experiments on the return of the vessel to the Thames, which had been ordered by the Admiralty, and was fully designed to have taken place by Sir James Ross, was also omitted. It appears therefore that in every instance in which the proper experiments were made, the disturbances were found to be consistent with the hypothesis of an induced magnetism conforming gradually to the changes in the terrestrial magnetic phenomena occasioned by the changes in the ship's geographical position, but not changing simultaneously with those changes. But whether the hypothesis of a gradual conformity of a part of the ship's iron, instead of an instantaneous conformity of the whole, to changes of the terrestrial dip, be or be not the true explanation of the facts which have been thus pointed out, the facts themselves are highly deserving of consideration by those to whom the correction of compass errors is of consequence; the anomalies which present themselves to any previously entertained systematic view are of too large amount, as well as too consistent on the different points, both in the observations at sea and in harbour, to be ascribed either to errors of observation or to accidents; and the promineney which has been given to them on this occasion will not be misplaced, if it should serve to impress upon those who have the power of carrying out practical suggestions, the importance of giving a sufficient trial to the method proposed by Mr. Archibald Smith in the eighth number of the Magnetic Contributions, whereby the variable term in the correction formula may be at all times determined experimentally at sea, by deflections of the compass needle obtained with the ship's head on two opposite points of the compass. The observations needed are extremely simple, require no unusual circumstances of weather and no reference to celestial objects, and need occupy but a very few minutes. Mr. Smith has shown that the variable term may also be determined at sea by observations of azimuths with the ship's head placed on the points of greatest disturbance; but the deflection method promises to be even more simple than that by azimuths. By the addition of a brass bar attached at right angles to the prism and sight vane of the azimuth ring of the standard compass, deflecting magnets may be temporarily fixed at a convenient distance from the compass needle, and the deflections measured with the ship's head on two opposite points; as was first practised by Captain (then Lieut.) Henry Clerk, R.A., F.R.S., in his Antarctic voyage*. If this method of determining the variable coefficient in the correction formulae be found to answer its purpose on a further and sufficient trial, the correction of the disturbances occasioned by the ship's iron might be still further simplified by the formation of tables of each term for every probable value of the coefficients, when the only calculation remaining to be made would be the addition of the quantities to be taken out from the tables. In wooden ships, two terms, and consequently a single addition, would probably, in most cases, be sufficient for the whole amount of the correction†. With reference to the corrections which we have now occasion to employ for the declinations observed in the Erebus in her passage from England to the Cape of Good Hope, we have the following values of the constant coefficients A, D and E in the formula (6.)‡, derived from the observations on the thirty-two points of the compass, at the several stations at which these observations were repeated, by the equations (16.), (19.) and (20.)§. | | A | D | E | |----------------|-----|-----|-----| | Gillingham | +15 | +16 | -3 | | Port Praya | -23 | +24 | -8 | | St. Helena | | +27 | +3 | | Cape of Good Hope, 1840 | +23 | +23 | +15 | | Mean | +5 | +22 | +2 | * Philosophical Transactions, 1846, p. 347. † Whilst these pages were in the press, tables such as are here referred to have been drawn up and printed under the direction of the Admiralty in a tract entitled "Directions for ascertaining at any time, whether at sea or in harbour, the changing part of the Deviation in the Compass occasioned by the Ship's Iron." ‡ Philosophical Transactions, 1846, p. 348. § Ibid. pp. 350 and 351. From the small amount of the mean value of A, we may infer that the iron which affected the compass was distributed systematically, or nearly so, on either side of the midship line; the variations in the values at different stations are greater than could be wished, but they have no regular appearance, and may probably be due to accidental circumstances, which in such experiments cannot possibly be wholly guarded against. Considering the small mean value of the coefficient, and the extent of its variations on the different occasions, we may dispense altogether with its further consideration. A similar remark will apply to E; since if its mean value were employed, the maximum effect on the correction would in no instance exceed two minutes. But it is otherwise with regard to D, which has a very sensible value in respect to the whole amount of the correction, especially in low latitudes; and the deductions in regard to it are tolerably consistent at the different stations; I have taken its mean value at +22'. For the variable coefficients B and C, we have not the advantage of possessing the experimental determinations at sea, which have been pointed out as possible to be made on future occasions with the deflecting apparatus; and we must therefore obtain these also from the observations in harbour in the best manner that circumstances will admit. Commencing with B as the more important, we have the following values at the four stations for the passages between which the corrections are required. (The values are expressed by the sines of the respective arcs): | Location | Dip. | B | |------------------------|----------|---------| | Gillingham, September 20, 1839 | +69° 05' | +0.0675 | | Port Praya, November 18, 1839 | +45° 32' | +0.0324 | | St. Helena, February 8, 1840 | -20° 06' | +0.0073 | | Cape of Good Hope, April 4, 1840 | -53° 02' | -0.0219 | If from these values of B we seek intermediate values corresponding to intermediate dips or times, we are obliged, for the reasons already stated, to have recourse to some more or less arbitrary supposition. It has been already shown that the intermediate values cannot be computed directly from the observations of the dip; and if the explanation which has been proposed be correct, it may not be unreasonable to regard the variation of this coefficient as a function of the time elapsed rather than of the change of dip. In two of the three passages at least, viz. from the British Channel to Port Praya and from St. Helena to the Cape, this might be the more safely assumed, because the ship's progress with respect to the terrestrial dip was uninterrupted, in the first case to diminishing north dips, and in the second to diminishing south dips. In the first case we have a change in B of '0351 in fifty-nine days, or '00059 per diem, and in the second of '0292 in fifty-six days, or '00052 per diem. In the voyage from Port Praya to St. Helena the progress in respect to the change of dip was uninterrupted from the period of departure from Port Praya on the 21st of November 1839 to the 2nd of January 1840, the dip having diminished in that interval from +45° 32' at Port Praya to between -29° and -30°. But from the 2nd of January the ship, in beating up to St. Helena, gradually though interruptedly, diminished the southerly dip, which at St. Helena is about $-20^\circ$. The 2nd of January may therefore be regarded as dividing this part of the voyage into two portions in respect to the changes of B. As the daily rates of change deduced above for the passages from the Thames to Port Praya and from St. Helena to the Cape (00059 and 00052) differ so little from each other, we may not unreasonably take their mean as applicable to the first division of this part of the voyage, or for that division in which the change of dip was continuous and uninterrupted. This gives as the value of B on the 2nd of January $+0074$. Now at St. Helena we find it by experiment $+0073$; on this assumption consequently the magnetism of the ship would have remained nearly stationary from the 2nd of January to the arrival at St. Helena, which is by no means an improbable supposition. We may derive intermediate values of C in a similar manner*. This coefficient is however of very minor importance. It will of course be understood that this mode of deriving these coefficients is one which would only be adopted in the absence of more satisfactory data; and fortunately in the part of the globe for which the corrections are required the values of B and C are less significant than in the higher latitudes. The observations themselves, however, furnish a test by which the appropriateness of this or of any other hypothesis proposed for their correction may be judged, viz. by the measure of agreement into which the corrections bring observations made on the same day or near the same spot with the ship’s head on different points. Without entering into details, it may be stated, generally, that the corrections computed by the formula (6.) with the value of the coefficients as above stated appear to bear this test very satisfactorily; the observations thus corrected becoming much more accordant with each other than either when uncorrected, or than when corrected by the same formula with its variable coefficients made to vary in accordance with the dip. *Determinations in H.M.S. Erebus, in 1842 and 1843, between Cape Horn and the Cape of Good Hope.* For the corrections of the declinations observed in the Erebus in 1842–43 between Cape Horn and the Cape of Good Hope, we have seen, p. 184, that the value of the constant coefficient D as derived from the experiments in the River Thames and Port Praya in 1839, and at St. Helena and the Cape of Good Hope in 1840 was $+22'$; for the experiments at the Falkland Islands in August 1842, $D=+23'$, and from those at the Cape in 1843, $+24'$; I have made no alteration therefore in the general table of corrections which was computed, as already noticed, with $+22'$. For the variable coefficients B and C we possess no other data, for the period now under consideration, than the values derivable from the experiments in the Falk- *Values of C derived from the harbour observations:— | Location | Value | |-------------------|---------| | Gillingham | -0036 | | Port Praya | -0046 | | St. Helena | -0033 | | Cape of Good Hope | -0044 | land Islands in August 1842, and at the Cape of Good Hope in April 1843; from these we obtain, At the Falkland Islands . . . . B = -0.0377; C = +0.0009. At the Cape of Good Hope . . . . B = -0.0517; C = -0.0040. It has been already noticed that the term $\sqrt{B^2+C^2}$, derived from these values, was on both occasions numerically greater than would have been assigned from the dips at the respective stations, and the values of the same coefficients at other stations where the ship had remained sufficiently long for the full development of the changes in its induced magnetism corresponding to changes of geographical position. The experiments at the Falkland Islands and at the Cape of Good Hope, afford however the best indication which we possess of the magnetic state of the ship in the interval comprised between their respective dates, and must be taken as the foundation of the corrections during that interval. In September 1842 the Erebus quitted Port Louis in the Falkland Islands for Cape Horn, and after remaining some weeks at St. Martin’s Cove, where the dip was between -58° and -59°, returned in November to the Falkland Islands; from whence she sailed immediately afterwards to resume the magnetic survey of the higher latitudes, arriving at the Cape of Good Hope in April 1843. In the whole interval between August 1842 and April 1843, the ship was at no time in a lower dip than that at the Falkland Islands, and we may presume therefore, with much probability, that the $\sqrt{B^2+C^2}$ was in no part of the interval less than its value at Port Louis. We have thus a minimum value for this term. During January 1843 the dips observed in the Erebus ranged, in different localities, from -60° to -63°. In February from -58° to -62°; in the first week of March a favourable opportunity presenting itself for pressing to the southward, the dip increased to between -65° and -66°; but from the 8th of March it progressively diminished until the arrival at the Cape on the 6th of April. The experiments made at the Cape on the 20th of that month gave a value of $\sqrt{B^2+C^2}$, corresponding to -63°, or thereabouts. It is not probable from this review that $\sqrt{B^2+C^2}$ was at any time much higher than it was found at the Cape; it may possibly have been a little higher for some days in March, but I have thought it safer to keep within the limits which were actually observed than to assume a conjectural maximum; and in correcting the declinations of this period I have accordingly taken the value of $\sqrt{B^2+C^2}$ observed at Port Louis as applicable until the Erebus sailed for the higher latitudes in December 1842, and have then increased it uniformly and progressively with the time until the first week in January 1843, when the dip was -63°, corresponding to the highest observed value of $\sqrt{B^2+C^2}$; and I have used that value thenceforward until the arrival at the Cape, where it accorded with the experiments. By the following memorandum with which I have been furnished by Mr. Tucker, Master of the Erebus, it appears that the standard compass of that ship had an index error of considerable amount during this portion of the voyage. I have not been able to learn anything satisfactory in regard to the cause of this error, which did not exist when the compass was tried by Captain Johnson, R.N., before the expedition quitted England; nor could it have existed when the ship was swung in the River Thames, at Port Praya, or at the Cape of Good Hope in 1840, or it would have appeared to its full amount in the value derived for the coefficient A. The evidence, however, afforded by the consistent results of the several trials that were made both at the Falkland Islands and at St. Martin's Cove in 1842, and both on shore and on board, leaves no doubt of the existence of index error at that period. I cannot find that any trial was made of the index error of this compass on the arrival at the Cape in April 1843; but in the neighbourhood of the Cape the Erebus crossed the track of the Pagoda, the observations of which ship are published in the Philosophical Transactions for 1846, Part III., and the declinations observed in the two ships agree when the index error observed at the Falkland Islands is employed for the compass of the Erebus, but would disagree to an amount of nearly two degrees if that correction were not employed. Mr. Tucker's memorandum is as follows: "The compass error of the standard compass of the Erebus was ascertained at Port Louis in the Falkland Islands, on the 13th of August 1842, in the following manner. The compass with its card CCH was taken on shore, and its tripod was fixed over the spot on which the transit had been established; the bearings of the N. and S. meridian marks were then taken with the compass as follows: North mark . . . . N. 15° 36' 8 W. South mark . . . . S. 15° 40' E. The true declination was 17° 33' E. in the month of August by the declinometers of the observatory; the error of the standard compass was therefore 17° 33' - 15° 38' 5 = 1° 54' 5, or the north end pointed 1° 54' 5 to the west of the true magnetic north. The compass was taken again on shore at the same place in September and December, and at St. Martin's Cove in November, and the compass error was tried in the same way, and was found on all those occasions to be within a few minutes the same as that above stated. Also when the ship was swung at Port Louis on the 19th of August 1842, the sum of the declinations observed with the standard compass in its usual place on board, on the thirty-two points, divided by thirty-two, made a mean declination of -15° 39' 3; the true magnetic declination in the same month by the declinometer was -17° 33', whence the compass error equals 1° 53' 7 to the westward of north." In conformity with this memorandum I have employed -1° 54' as an index correction from August 1842 to April 1843. Determinations in H.M.S. Terror, in 1842 and 1843, between Cape Horn and the Cape of Good Hope. The disturbance of the compass of the Terror was examined at the Falkland Islands on the 17th of August 1842, and at the Cape of Good Hope on the 20th of April 1843, by azimuths observed with the ship's head successively on the thirty-two points. Assuming the mean of the azimuths on the thirty-two points to give the true declination (i.e. the coefficient $A=0$), the disturbance on the several points are as follows, viz.— **Table II.—Disturbance of the Compass in H.M.S. Terror.** | Ship's head | Disturbances towards the west. | Disturbances towards the west. | |-------------|--------------------------------|--------------------------------| | | Falkland Islands, Aug. 17, 1842. | Cape of Good Hope, April 20, 1843. | | N. | +0° 18' | -0° 58' | | N. by W. | -0° 02' | -1° 3' | | N.N.W. | -0° 17' | -1° 6' | | N.W. by N. | -0° 48' | -1° 22' | | N.W. | -1° 19' | -2° 20' | | N.W. by W. | -1° 49' | -2° 12' | | W.N.W. | -1° 47' | -3° 14' | | W. by N. | -2° 07' | -3° 35' | | W. | -2° 30' | -3° 36' | | W. by S. | -2° 21' | -3° 8' | | W.S.W. | -2° 12' | -2° 35' | | S.W. by W. | -2° 21' | -2° 1' | | S.W. | -1° 33' | -1° 33' | | S.W. by S. | -1° 05' | -1° 26' | | S.S.W. | -0° 47' | -1° 22' | | S. by W. | -0° 45' | -0° 9' | From these we have $D=+17'$ and $E=+6'$; also $\sqrt{B^2+C^2}=-0.040$ at the Falkland Islands, and $-0.054$ at the Cape. For the reasons assigned in the case of the Erebus, I have taken $-0.040$ as applicable until the Terror sailed to the higher latitudes in December 1842, and have then increased it uniformly and progressively with the time until the first week in January 1843, when the south dip was greatest; and from this date until the arrival at the Cape I have employed $-0.054$ (observed at the Cape), which was the greatest observed value of this term. The compass employed in this portion of the Terror’s voyage was made by Cummins, and had two cards, a light and a heavy one, the latter being used exclusively in very bad weather. In a memorandum which I received from Captain Crozier, it is stated that the index errors were examined at the observatory in the Falkland Islands on the 23rd of August 1842, and found to require corrections, with the light card of $+1° 13'$, and with the heavy card of $-0° 40'$. The cause of these errors does not appear to have been examined either during the voyage or after the return to England. The error of the light card, which was the one generally used, is in the opposite direction to the error assigned to the compass of the Erebus examined at the same time; and it is remarkable that throughout this portion of the voyage in which the two ships were always in company, the declinations observed in the Erebus are generally still more easterly than those of the Terror after the corrections for the compass error are applied, and that this disagreement would be greater if the corrections were not so applied. I have therefore felt the less hesitation in admitting and employing compass errors of such magnitude, the cause of which does not appear to have undergone investigation; but I cannot avoid expressing the hope that as the state of the compasses supplied to Her Majesty's navy has at length received from the Admiralty the attention which was so long and so greatly wanted, and since a department has been expressly instituted for their proper examination and care, errors of such magnitude, where no such errors need exist, may no longer be found to occur*. I would also take this occasion to remark, that in examining the disturbance caused by the ship's iron at the spot in which the standard compass is placed by the process of swinging the ship, the standard compass itself should be employed, and not, as appears to have been sometimes done, another compass substituted for that particular occasion. When compass errors exist, the coefficient A derived from the observations with one compass are inapplicable to the observations of another compass having a different compass error. Also, when circumstances permit, it is preferable that the actual disturbance on each point should be ascertained independently of that on other points, as is done when the bearing of an object is observed whose correct magnetic bearing is known or subsequently determined. Disturbances supposed to be ascertained, by comparing azimuths observed on each point with the means of the azimuths observed on all the points, are liable to be in error to the full amount of the value of the coefficient A, whether that value arise from compass error or from the disturbing influence of the iron. Determinations made in H.M.S. Thunder, in a passage from Nassau, New Providence, to England in 1841, by Captain Edward Barnett, R.N. The observations in the Thunder were made with one of the Admiralty compasses, fitted as a standard compass. The disturbance occasioned by the iron was examined at Nassau in March 1841, immediately after the arrival of the ship from England, and at Gillingham in the River Medway, about the 1st July of the same year on her return to England. The observations were as follows, viz.— **Table III.—Disturbance of the Compass in H.M.S. Thunder.** | Ship's head | Disturbances towards the west. | Disturbances towards the west. | |-------------|-------------------------------|-------------------------------| | | Nassau. | Gillingham. | | N. | -0° 5' | -0° 15' | | N. by w. | +1° 19' | +1° 00' | | N.N.W. | +1° 16' | +1° 59' | | N.W. by N. | +2° 18' | +3° 38' | | N.W. | +2° 48' | +5° 02' | | N.W. by w. | +3° 32' | +6° 2' | | W.N.W. | +3° 53' | +6° 6' | | W. by N. | +3° 45' | +6° 12' | | W. | +3° 52' | +6° 15' | | W. by s. | +3° 44' | +6° 51' | | W.S.W. | +3° 21' | +5° 15' | | S.W. by w. | +2° 59' | +5° 42' | | S.W. | +2° 37' | +5° 2' | | S.W. by s. | +1° 55' | +3° 32' | | S.S.W. | +1° 52' | +2° 40' | | s. by w. | +0° 34' | +2° 5' | | Ship's head | Disturbances towards the west. | Disturbances towards the west. | |-------------|-------------------------------|-------------------------------| | | Nassau. | Gillingham. | | S. | +0° 23' | +0° 38' | | S. by E. | +0° 1' | -1° 17' | | S.S.E. | -0° 34' | -1° 25' | | S.E. by S. | -0° 43' | -3° 35' | | S.E. | -1° 22' | -4° 2' | | S.E. by E. | -2° 1' | -4° 23' | | E.S.E. | -2° 36' | -5° 19' | | E. by S. | -3° 9' | -5° 50' | | E. | -3° 19' | -6° 16' | | E. by N. | -3° 26' | -5° 44' | | E.N.E. | -3° 34' | -6° 28' | | N.E. by E. | -3° 12' | -5° 57' | | N.E. | -2° 52' | -4° 46' | | N.E. by N. | -2° 16' | -3° 48' | | N.N.E. | -1° 56' | -2° 51' | | N. by E. | -0° 27' | -0° 51' | * When the Erebus left England the prism by which the graduation of the card of the Admiralty compasses From these we obtain $A = +8'$; $D = +14'$; $E = -2'$; $B$ at Nassau = +0.062, and at Gillingham +0.111; $C$ at Nassau = -0.006, and at Gillingham = -0.007. From Nassau the Thunder passed immediately into dips on the coast of America higher than those in the subsequent portion of her voyage, or than the dip at Gillingham. The variable part of the disturbance therefore, probably, increased rapidly after leaving Nassau, and may have been greater whilst the ship was off the coast of America than when examined at the termination of the voyage. Having no intermediate data, however, I have not ventured to exceed the maximum observed value of $\sqrt{B^2 + C^2}$, but have commenced with +0.062, the observed value at Nassau on the 1st of May, and increased it uniformly with the time to +0.111, the observed value at Gillingham, and have supposed it to have attained the latter value on or about the 1st of June; when the ship had been a fortnight in dips exceeding that in the Thames. **Determinations in the Prince Regent Transport, on the passage from England to Canada in 1842, by Lieutenant (since Captain) J. H. Lefroy, R.A.** These observations were made by Lieut. Lefroy when proceeding to Canada in 1842 to take charge of the Magnetic Observatory at Toronto. By direction of the Hydrographer, Lieut. Lefroy was furnished with one of the Admiralty compasses, which was fixed as a standard in the usual manner. The Prince Regent was swung at Greenhithe by Captain Johnson, R.N., from whom I received the following table of deviations. **Table IV.—Disturbance of the Compass in the Prince Regent Transport.** | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | |--------------|-----------------------------|--------------|-----------------------------|--------------|-----------------------------|--------------|-----------------------------| | N. by W. | +0° 45' | W. by S. | +2° 40' | S. by E. | +0° 05' | E. by N. | -2° 00' | | N.N.W. | +1° 55' | W.S.W. | +2° 20' | S.S.E. | -0° 10' | E.N.E. | -1° 45' | | N.W. by N. | +2° 05' | S.W. by W. | +2° 05' | S.E. by S. | -0° 35' | N.E. by E. | -1° 35' | | N.W. | +2° 15' | S.W. | +2° 00' | S.E. | -0° 35' | N.E. | -1° 05' | | N.W. by W. | +2° 15' | S.W. by S. | +1° 35' | S.E. by E. | -1° 05' | N.E. by N. | -0° 25' | | W.N.W. | +2° 25' | S.S.W. | +1° 15' | E.S.E. | -2° 00' | N.N.E. | -0° 15' | | W. by N. | +2° 30' | S. by W. | +1° 05' | E. by S. | -2° 05' | N. by E. | -0° 10' | | W. | +2° 25' | S. | +0° 25' | E. | -2° 05' | N. | +0° 05' | From this table we have the following values of the coefficients: Permanent coefficients $\begin{cases} A + 27' \\ D + 5 \\ E + 10 \end{cases}$ Variable coefficients $\begin{cases} B + 0.0389 \\ C - 0.0001 \end{cases}$ was read, had a motion of adjustment to suit different eyes. An adjustment of this nature was found liable to introduce errors, and has since been discontinued. The prisms are now fixed, immovably, at a distance from the card adapted for eyes of ordinary vision. Circumstances did not permit the Prince Regent to be swung on her arrival at Quebec, and we have no other means of assigning the variations of B (C being so small that it may be disregarded) than by assuming it to have varied as the tangent of the dip, which increased from 69° in the Thames to 79° at the entrance of the River St. Lawrence. Upon this supposition $B = \frac{0.0389 \tan \theta}{\tan 65^\circ} = 0.015 \tan \theta$, $\theta$ being the dip at the place of observation; the deviations on the several points in different dips are then given by $$\sin \delta = 27' + 0.0149 \tan \theta \sin \zeta' + 5' \sin 2\zeta' + 10' \cos 2\zeta',$$ and the corrections have been calculated accordingly. They appear generally to reconcile the results of the observations on the different courses very satisfactorily. **Determinations in H.M.S. Philomel, in a passage from Monte Video to England in 1846, by Captain Sullivan, R.N.** The observations of Captain Sullivan, R.N. were made in a passage from Monte Video to England in 1846 in H.M.S. Philomel. The error of the compass with the ship's head on different points was examined at Monte Video on the 14th of September 1844, and at Plymouth on the 10th of June 1846, as follows: ### Table V. **Disturbance of the Compass in H.M.S. Philomel, Monte Video, September 14, 1844.** | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | |--------------|-------------------------------|--------------|-------------------------------|--------------|-------------------------------|--------------|-------------------------------| | N. | -0° 57' | W. | -0° 40' | S. | +0° 16' | E. | +0° 03' | | N. by W. | -0° 58' | W. by S. | -0° 50' | S. by E. | +0° 39' | E. by N. | -0° 12' | | N.N.W. | -0° 56' | W.S.W. | -0° 48' | S.S.E. | +0° 49' | E.N.E. | -0° 26' | | N.W. by N. | -0° 50' | S.W. by W. | -0° 38' | S.E. by S. | +0° 55' | N.E. by E. | -0° 26' | | N.W. | -0° 49' | S.W. | -0° 40' | S.E. | +0° 55' | N.E. | -0° 22' | | N.W. by W. | -0° 50' | S.W. by S. | -0° 25' | S.E. by E. | +0° 55' | N.E. by N. | -0° 29' | | W.N.W. | -0° 40' | S.S.W. | -0° 10' | E.S.E. | +0° 43' | N.N.E. | -0° 45' | | W. by N. | -0° 43' | S. by W. | +0° 03' | E. by S. | +0° 22' | N. by E. | -0° 55' | Plymouth, June 10, 1846. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | |--------------|-------------------------------|--------------|-------------------------------|--------------|-------------------------------|--------------|-------------------------------| | N. | -0° 20' | W. | +1° 27' | S. | -0° 55' | E. | -0° 32' | | N. by W. | -0° 19' | W. by S. | +1° 58' | S. by E. | -1° 09' | E. by N. | -4° 36' | | N.N.W. | -0° 12' | W.S.W. | +0° 46' | S.S.E. | -1° 37' | E.N.E. | -4° 07' | | N.W. by N. | +0° 30' | S.W. by W. | +0° 34' | S.E. by S. | -2° 02' | N.E. by E. | -4° 34' | | N.W. | +0° 52' | S.W. | +0° 33' | S.E. | -1° 20' | N.E. | -3° 16' | | N.W. by W. | +2° 13' | S.W. by S. | +0° 11' | S.E. by E. | -1° 27' | N.E. by N. | -3° 12' | | W.N.W. | +2° 39' | S.S.W. | +0° 05' | E.S.E. | -2° 47' | N.N.E. | -2° 11' | | W. by N. | +2° 30' | S. by W. | -0° 30' | E. by S. | -3° 37' | N. by E. | -1° 26' | The mean values of A, D and E, from the preceding observations, are $A = -35'$; $D = +26'$; and $E = +2'$. B at Monte Video = $-0.0094$; and at Plymouth $+0.0480$; C $-0.0095$ at Monte Video, and $-0.0031$ at Plymouth. Assuming the values of B to have been the same when the Philomel left Monte Video for England in April 1846 as when she was swung at that station in September 1844, and that its alteration in the passage between Monte Video and Plymouth was uniform in respect to time, we have the change in the variable term of the correction from $-0.013$ on the 27th of April 1846 to $+0.048$ on the following 10th of June; being at the rate of $+0.0014$ for each day. The corrections have been applied in accordance with these values of the coefficients. Determinations in the Hudson’s Bay Company’s ship the Prince Albert, in a passage from England to Hudson’s Bay and back, in 1846, by Lieut. (since Commander) T. E. L. Moore, R.N. The observations of Lieut. T. E. L. Moore, R.N., were made in a voyage from the Thames to Moose Fort in Hudson’s Bay and back in the summer of 1846, in the Hudson’s Bay Company’s ship “Prince Albert,” in which ship Lieut. Moore embarked by direction of the Admiralty for the purpose of making magnetic observations in compliance with a recommendation to that effect from the Royal Society. Lieut. Moore was supplied with one of the Admiralty compasses fixed as a standard compass; the ship was swung at Greenhithe on the 4th of June 1846 (before her departure from the Thames), and the influence of the iron examined on the eight principal points of the compass as follows: | Table VI.—Disturbance of the Compass in the Hudson’s Bay Company’s ship Prince Albert. | |-----------------------------------------------| | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | Ship's head. | Disturbance towards the west. | | N. | $-0° 48'$ | W. | $+1° 12'$ | S. | $+0° 20'$ | E. | $-1° 30'$ | | N.W. | $+1° 00'$ | S.W. | $+0° 40'$ | S.E. | $-0° 40'$ | N.E. | $-1° 10'$ | From whence we obtain $A = -11'$; $D = +12'$; $E = -2'$; $B = +0.0236$; $C = -0.0099$; the (approximate) inclination being $68° 52'$. On the 26th and 27th of August following, the “Prince Albert” being then at the anchorage at Moose Fort in Hudson’s Bay, her head was placed successively on seven of the same points (N.W. being omitted on account of difficulties arising from the strength of the tide), and the bearing of an object ten miles distant was observed with the head on each point. The bearings were as follows: | N. | S. 65° 00' W. | |--------|---------------| | N.W. | | | W. | S. 67° 00 W. | | S.W. | S. 66° 20 W. | | S. | S. 65° 00' W. | |--------|---------------| | S.E. | S. 63° 40 W. | | E. | S. 62° 00 W. | | N.E. | S. 62° 10 W. | The correct magnetic bearing of the distant object from the ship (or that which would have been shown by the ship's compass with her head on each of the points if there had been no local attraction) does not appear to have been observed; we can obtain from the observations therefore only the differences of the bearings on the different points. From these we have the half difference of the bearings at east and west, $2°\ 30'$ = (nat. sine '0436) = $\sqrt{B^2+C^2}$ at Moose Fort, where the (approximate) inclination = $81°\ 00'$. Taking the value of the $\sqrt{B^2+C^2}$ at Greenhithe in conformity with the observations there at '025, and assuming that its variation should be as the tangent of the inclination, we should have $\frac{'025 \tan 81°\ 0}{\tan 68°\ 52'}$ = '062 as its value at Moose Fort, if the change in the induced magnetism of the ship had kept pace with the change in the terrestrial dip. Here, as in other cases, the variation of $\sqrt{B^2+C^2}$ was in arrear of the change of the inclination, since the observed value '0436 corresponds to a dip of only $77°\ 13'$. The whole amount of the deviation in the "Prince Albert" is, however, so extremely small in comparison with vessels of war (the extremes at the east and west points not exceeding $1°\ ½$ at the Thames and $2°\ ½$ at Hudson's Bay), that we should obtain a sufficient approximation to the true variation of this term, whether we assumed it to vary with the change of dip, or uniformly with the lapse of time. I have taken the latter as the more convenient and ready mode; increasing the coefficient from +'025 on the 4th of June '0002 per diem, to +'0436 on the 26th of August, and diminishing it at the same rate from the 9th of September, on which day the Prince Albert began to lower the dip on her homeward voyage, to the end of the month when she entered the British channel. **Determinations in H.M.S. Rattlesnake in a passage from England to the Cape of Good Hope, in 1847, by Captain Owen Stanley, R.N.** The influence of the iron on the Rattlesnake's standard compass was examined at Portsmouth, November 30, 1846, and again at Port Jackson in September 1847, circumstances having prevented a satisfactory repetition of the experiments during a short stay at the Cape of Good Hope. From the observations at Portsmouth in 1846, as subjoined, we obtain the values of $A = -30'$; $D = +25'$, and $E = +5'$. TABLE VII.—Disturbance of the Compass in H.M.S. Rattlesnake. | Ship's head | Disturbance towards the west | Ship's head | Disturbance towards the west | Ship's head | Disturbance towards the west | Ship's head | Disturbance towards the west | |-------------|-----------------------------|-------------|-----------------------------|-------------|-----------------------------|-------------|-----------------------------| | N. | -6° 50 | W. | +1° 30 | S. | +0° 30 | E. | -3° 20 | | N.N.W. | +2° 10 | W.S.W. | +0° 40 | S.S.E. | -1° 50 | E.N.E. | -4° 30 | | N.W. | +3° 40 | S.W. | +1° 50 | S.E. | -2° 30 | N.E. | -3° 50 | | W.N.W. | +2° 35* | S.S.W. | +1° 15* | E.S.E. | -2° 55* | N.N.E. | -2° 20 | The observations at Portsmouth give $B = +0.0565$ with a dip (approximate) of $+68° 40'$: by their repetition at Port Jackson in the September following $B$ was found to have changed to $-0.0305$, with a dip (approximate) of $-62° 48'$. The magnetism of the iron in the Rattlesnake was therefore, for the most part at least, of the nature of induced magnetism; but the value of $B$ in this case, as in others where the ship had materially changed her geographical position, was in arrear on her arrival at Port Jackson of the change which had taken place in the terrestrial dip; it corresponded to a dip of $-54° 5'$ instead of $-62° 48'$. Being only concerned at present with the observations as far as the Cape of Good Hope, I have taken the $\sqrt{B^2 + C^2} = +0.056$ at Portsmouth, which is its value derived from the observations at that port; and having no materials from which the subsequent variation of this term might be more correctly computed, I have assumed it to have varied as the tangent of the dip, which is no doubt approximately true. The results of the observations which have been thus severally described are contained in the general table No. XII. at the close of this memoir, arranged in zones of latitude, and in the order of their respective longitudes. This table also contains the correction of each result to the mean epoch of January 1840. The original manuscripts of the unpublished portion of the observations from which these results are derived, together with tabular abstracts containing the details of the corrections applied for the ship’s iron, will be deposited in the Hydrographic Office. The subjoined Table, No. VIII., contains the particulars of the groups into which the results have been formed. The mean declinations at the points of intersection, shown in the final column of the table, constitute the elements from which the declination lines in the map are derived; the lines having been drawn in accordance with them, with only such slight deviations as were indispensable to preserve an interconformity between the lines in a few instances where it was obvious that the elements themselves were slightly discordant with each other. * Interpolated. ### Table VIII.—Elements of the Declination Lines. | Intersections | Observations employed | Number of additional observations | Total number of observations | Mean declination at the point of intersection | |---------------|-----------------------|----------------------------------|-----------------------------|---------------------------------------------| | Lat. | Long. | Between the latitudes of | Between the longitudes of | | | | | 60°-0 and 65°-0 | 280°-0 and 290°-0 | | | 62°-5 | 285°-0 | ... | ... | 7 | 55° 17 | | 62°-5 | 290°-0 | 60°-0 and 65°-0 | 280°-0 and 300°-0 | 12 | 56 48 | | 60°-0 | 290°-0 | 50°-0 and 70°-0 | 285°-0 and 295°-0 | 8 | 49 07 | | 60°-0 | 295°-0 | 58°-5 and 62°-5 | 290°-0 and 300°-0 | 5 | 52 20 | | 60°-0 | 335°-0 | 58°-0 and 62°-0 | 350°-0 and 0°-0 | 12 | 29 01 | | 57°-5 | 310°-0 | 54°-0 and 61°-0 | 302°-5 and 317°-5 | 6 | 46 52 | | 57°-5 | 315°-0 | 55°-0 and 60°-0 | 305°-0 and 325°-0 | 7 | 45 22 | | 57°-5 | 320°-0 | 55°-0 and 60°-0 | 305°-0 and 335°-0 | 10 | 43 38 | | 57°-5 | 325°-0 | 55°-0 and 60°-0 | 315°-0 and 335°-0 | 8 | 42 05 | | 57°-5 | 330°-0 | 55°-0 and 60°-0 | 320°-0 and 340°-0 | 10 | 39 55 | | 57°-5 | 335°-0 | 56°-0 and 59°-0 | 320°-0 and 350°-0 | 10 | 37 29 | | 57°-5 | 340°-0 | 55°-0 and 60°-0 | 325°-0 and 355°-0 | 16 | 34 59 | | 57°-5 | 345°-0 | 55°-0 and 60°-0 | 336°-0 and 354°-0 | 10 | 32 35 | | 57°-5 | 350°-0 | 55°-0 and 60°-0 | 345°-0 and 355°-0 | 12 | 30 20 | | 57°-5 | 355°-0 | 55°-0 and 60°-0 | 352°-5 and 357°-5 | 12 | 27 56 | | 57°-5 | 357°-5 | 54°-0 and 61°-0 | 355°-0 and 0°-0 | 13 | 26 58 | | 55°-0 | 300°-0 | 49°-0 and 61°-0 | 297°-5 and 302°-5 | 4 | 40 48 | | 55°-0 | 305°-0 | 50°-0 and 60°-0 | 302°-5 and 307°-5 | 2 | 41 37 | | 55°-0 | 310°-0 | 50°-0 and 60°-0 | 303°-0 and 317°-0 | 1 | 41 42 | | 55°-0 | 315°-0 | 50°-0 and 60°-0 | 305°-0 and 325°-0 | 2 | 41 54 | | 55°-0 | 320°-0 | 50°-0 and 60°-0 | 310°-0 and 330°-0 | 12 | 41 14 | | 55°-0 | 325°-0 | 50°-0 and 60°-0 | 320°-0 and 330°-0 | 7 | 39 50 | | 55°-0 | 330°-0 | 50°-0 and 60°-0 | 320°-0 and 340°-0 | 13 | 37 56 | | 55°-0 | 335°-0 | 50°-0 and 60°-0 | 325°-0 and 345°-0 | 2 | 35 42 | | 55°-0 | 340°-0 | 50°-0 and 60°-0 | 330°-0 and 350°-0 | 1 | 33 51 | | 55°-0 | 345°-0 | 50°-0 and 60°-0 | 339°-0 and 351°-0 | 1 | 31 45 | | 55°-0 | 350°-0 | 50°-0 and 60°-0 | 345°-0 and 355°-0 | 1 | 29 33 | | 55°-0 | 355°-0 | 52°-5 and 57°-5 | 350°-0 and 0°-0 | 4 | 27 17 | | 55°-0 | 0°-0 | 52°-5 and 57°-5 | 357°-5 and 2°-5 | 3 | 24 54 | | 52°-5 | 350°-0 | 50°-0 and 55°-0 | 347°-5 and 352°-5 | ... | 28 41 | | 52°-5 | 355°-0 | 50°-0 and 55°-0 | 352°-5 and 357°-5 | 1 | 26 15 | | 52°-5 | 0°-0 | 50°-0 and 55°-0 | 357°-5 and 2°-5 | 12 | 23 50 | | 50°-0 | 280°-0 | 48°-0 and 52°-0 | 279°-0 and 281°-0 | ... | 9 01 | | 50°-0 | 295°-0 | 49°-0 and 51°-0 | 292°-5 and 297°-5 | 2 | 25 09 | | 50°-0 | 300°-0 | 47°-5 and 52°-5 | 297°-5 and 302°-5 | 11 | 29 49 | | 50°-0 | 305°-0 | 45°-0 and 55°-0 | 302°-5 and 307°-5 | 11 | 32 45 | | 50°-0 | 325°-0 | 47°-0 and 53°-0 | 319°-0 and 331°-0 | 8 | 34 32 | | 50°-0 | 330°-0 | 46°-0 and 54°-0 | 325°-0 and 335°-0 | 8 | 33 53 | | 50°-0 | 335°-0 | 42°-5 and 57°-5 | 330°-0 and 340°-0 | 23 | 31 52 | | 50°-0 | 340°-0 | 42°-5 and 57°-5 | 335°-0 and 345°-0 | 24 | 30 21 | | 50°-0 | 345°-0 | 42°-5 and 57°-5 | 340°-0 and 350°-0 | 21 | 28 52 | | 50°-0 | 350°-0 | 47°-5 and 52°-5 | 345°-0 and 355°-0 | 15 | 27 14 | | 50°-0 | 355°-0 | 45°-0 and 55°-0 | 352°-5 and 357°-5 | 13 | 25 22 | | 47°-5 | 290°-0 | 46°-5 and 48°-5 | 285°-5 and 291°-5 | 1 | 16 10 | | 47°-5 | 295°-0 | 45°-0 and 50°-0 | 292°-5 and 297°-5 | 28 | 20 50 | | 47°-5 | 300°-0 | 45°-0 and 50°-0 | 297°-5 and 302°-5 | 12 | 25 09 | | 47°-5 | 305°-0 | 45°-0 and 50°-0 | 300°-0 and 310°-0 | 7 | 28 24 | | 47°-5 | 325°-0 | 42°-5 and 52°-5 | 322°-5 and 327°-5 | 9 | 31 41 | | 47°-5 | 330°-0 | 45°-0 and 50°-0 | 325°-0 and 335°-0 | 7 | 31 02 | | 47°-5 | 335°-0 | 45°-0 and 50°-0 | 330°-0 and 340°-0 | 12 | 29 44 | | 47°-5 | 340°-0 | 45°-0 and 50°-0 | 335°-0 and 345°-0 | 16 | 29 14 | | 47°-5 | 345°-0 | 45°-0 and 50°-0 | 340°-0 and 350°-0 | 11 | 27 50 | | 47°-5 | 350°-0 | 45°-0 and 50°-0 | 345°-0 and 355°-0 | 14 | 26 11 | | 47°-5 | 355°-0 | 45°-0 and 50°-0 | 350°-0 and 0°-0 | 13 | 24 34 | | 45°-0 | 285°-0 | 43°-5 and 46°-5 | 283°-0 and 287°-0 | 15 | 7 54 | | 45°-0 | 290°-0 | 40°-0 and 50°-0 | 289°-0 and 291°-0 | 27 | 13 08 | ### Table VIII. (Continued.) | Intersections | Observations employed | Number of additional observations | Total number of observations | Mean Declination at the point of intersection | |---------------|-----------------------|----------------------------------|-----------------------------|---------------------------------------------| | Lat. | Long. | Between the Latitudes of | Between the Longitudes of | | | | | 42°5 and 47°5 | 29°5 and 29°5 | | | 45° | 295° | 14 | 17°34' | | | 45° | 300° | 7 | 20°55 | | | 45° | 305° | 9 | 24°05 | | | 45° | 310° | 8 | 26°16 | | | 45° | 320° | 10 | 28°23 | | | 45° | 325° | 10 | 29°04 | | | 45° | 330° | 10 | 29°29 | | | 45° | 335° | 21 | 27°40 | | | 45° | 340° | 20 | 27°08 | | | 45° | 345° | 11 | 26°18 | | | 42°5 | 285° | 3 | 5°36 | | | 42°5 | 290° | 18 | 9°54 | | | 42°5 | 295° | 15 | 14°12 | | | 42°5 | 300° | 20 | 17°12 | | | 42°5 | 315° | 10 | 24°20 | | | 42°5 | 320° | 14 | 25°54 | | | 42°5 | 325° | 14 | 26°47 | | | 42°5 | 330° | 11 | 26°08 | | | 42°5 | 335° | 9 | 25°49 | | | 40° | 285° | 15 | 4°16 | | | 40° | 290° | 11 | 7°34 | | | 40° | 300° | 22 | 22°57 | | | 40° | 305° | 19 | 24°03 | | | 40° | 310° | 26 | 24°37 | | | 40° | 315° | 20 | 24°37 | | | 40° | 320° | 8 | 24°03 | | | 40° | 325° | 11 | 23°37 | | | 40° | 330° | 18 | 20°10 | | | 37°5 | 330° | 18 | 23°25 | | | 37°5 | 335° | 14 | 23°25 | | | 35° | 285° | 15 | 1°23 | | | 35° | 290° | 10 | 18°58 | | | 35° | 295° | 22 | 20°24 | | | 35° | 300° | 5 | 22°45 | | | 35° | 305° | 7 | 21°50 | | | 35° | 310° | 12 | 20°23 | | | 30° | 280° | 5 | 3°58 | | | 30° | 290° | 21 | 16°01 | | | 30° | 295° | 20 | 17°54 | | | 30° | 300° | 20 | 22°00 | | | 25° | 285° | 10 | 2°36 | | | 25° | 290° | 21 | 12°38 | | | 25° | 295° | 24 | 14°59 | | | 25° | 300° | 14 | 16°51 | | | 25° | 305° | 12 | 20°02 | | | 25° | 310° | 22 | 20°07 | | | 22°5 | 340° | 14 | 19°36 | | | 20° | 285° | 11 | 3°29 | | | 20° | 290° | 13 | 2°08 | | | 20° | 295° | 9 | 10°27 | | | 20° | 300° | 10 | 12°48 | | | 20° | 305° | 15 | 15°04 | | | 20° | 310° | 14 | 17°27 | | | 20° | 315° | 14 | 19°15 | | | 20° | 320° | 4 | 0°55 | | | 15° | 300° | 11 | 11°32 | | | 15° | 305° | 11 | 11°32 | | MDCCCLXIX. | Intersections | Observations employed | Number of additional observations | Total number of observations | Mean Declination at the point of intersection | |---------------|-----------------------|----------------------------------|-----------------------------|--------------------------------------------| | Lat. | Long. | Between the Latitudes of | Between the Longitudes of | | | | | 12°5 and 17°5 | 325°0 and 335°0 | | | 15°0 | 336°0 | ... | ... | 15 | | 15°0 | 335°0 | 12°5 and 17°5 | 330°0 and 340°0 | 23 | | 15°0 | 340°0 | 10°0 and 20°0 | 337°5 and 342°5 | 3 | | 10°0 | 330°0 | 5°0 and 15°0 | 326°0 and 334°0 | 15 | | 10°0 | 335°0 | 7°5 and 12°5 | 332°5 and 337°5 | 15 | | 10°0 | 340°0 | 7°5 and 12°5 | 337°5 and 342°5 | 1 | | 10°0 | 345°0 | 7°5 and 12°5 | 342°5 and 347°5 | 10 | | 5°0 | 300°0 | 0°0 and 10°0 | 296°0 and 304°0 | 10 | | 5°0 | 330°0 | 2°5 and 7°5 | 327°5 and 332°5 | 8 | | 5°0 | 335°0 | 2°5 and 7°5 | 332°5 and 337°5 | 12 | | 5°0 | 340°0 | 2°5 and 7°5 | 337°5 and 342°5 | 15 | | 5°0 | 345°0 | 0°0 and 10°0 | 340°0 and 350°0 | 17 | | 5°0 | 350°0 | 2°5 and 7°5 | 347°5 and 352°5 | 5 | | 5°0 | 355°0 | 2°5 and 7°5 | 350°0 and 360°0 | 10 | | 5°0 | 0°0 | 2°5 and 7°5 | 355°0 and 5°0 | 12 | | 5°0 | 5°0 | 0°0 and 10°0 | 0°0 and 10°0 | 12 | | 0°0 | 330°0 | + 2°5 and − 2°5 | 327°5 and 332°5 | 16 | | 0°0 | 335°0 | + 3°0 and − 3°0 | 331°0 and 339°0 | 14 | | 0°0 | 340°0 | + 3°0 and − 3°0 | 335°0 and 345°0 | 19 | | − 2°5 | 320°0 | 0°0 and − 5°0 | 312°5 and 327°5 | 6 | | − 5°0 | 325°0 | 0°0 and − 10°0 | 322°0 and 328°0 | 12 | | − 5°0 | 330°0 | − 2°5 and − 7°5 | 327°5 and 332°5 | 3 | | − 5°0 | 335°0 | − 1°0 and − 9°0 | 332°5 and 337°5 | 7 | | − 5°0 | 340°0 | − 1°0 and − 9°0 | 335°0 and 345°0 | 14 | | − 5°0 | 345°0 | 0°0 and − 10°0 | 342°5 and 347°5 | 15 | | − 10°0 | 325°0 | − 7°5 and − 12°5 | 322°5 and 327°5 | 9 | | − 10°0 | 327°5 | − 7°5 and − 12°5 | 325°0 and 330°0 | 14 | | − 10°0 | 330°0 | − 7°5 and − 12°5 | 327°5 and 332°5 | 17 | | − 10°0 | 340°0 | − 5°0 and − 15°0 | 335°0 and 345°0 | 10 | | − 10°0 | 345°0 | − 7°5 and − 12°5 | 342°5 and 347°5 | 10 | | − 15°0 | 322°5 | − 12°0 and − 18°0 | 321°0 and 324°0 | 30 | | − 15°0 | 327°5 | − 12°0 and − 18°0 | 325°0 and 330°0 | 16 | | − 15°0 | 330°0 | − 10°0 and − 20°0 | 328°0 and 332°0 | 14 | | − 15°0 | 345°0 | − 10°0 and − 20°0 | 342°5 and 347°5 | 11 | | − 15°0 | 350°0 | − 14°0 and − 16°0 | 347°5 and 352°5 | 15 | | − 15°5 | 352°5 | − 13°0 and − 17°0 | 350°0 and 355°0 | 17 | | − 17°5 | 355°0 | − 15°0 and − 20°0 | 352°5 and 357°5 | 19 | | − 20°0 | 320°0 | − 17°0 and − 23°0 | 317°5 and 322°5 | 17 | | − 20°0 | 325°0 | − 17°0 and − 23°0 | 324°0 and 326°0 | 12 | | − 20°0 | 330°0 | − 15°0 and − 25°0 | 327°5 and 332°5 | 12 | | − 20°0 | 345°0 | − 15°0 and − 25°0 | 342°5 and 347°5 | 10 | | − 20°0 | 350°0 | − 15°0 and − 25°0 | 347°5 and 352°5 | 14 | | − 20°0 | 355°0 | − 17°0 and − 23°0 | 350°0 and 0°0 | 13 | | − 22°5 | 5°0 | − 18°0 and − 27°0 | 2°0 and 8°0 | 5 | | − 25°0 | 315°0 | − 20°0 and − 30°0 | 313°0 and 317°0 | 16 | | − 25°0 | 320°0 | − 22°5 and − 27°5 | 317°5 and 322°5 | 13 | | − 25°0 | 325°0 | − 22°0 and − 28°0 | 322°0 and 328°0 | 7 | | − 25°0 | 330°0 | − 20°0 and − 30°0 | 325°0 and 335°0 | 13 | | − 25°0 | 335°0 | − 23°0 and − 27°0 | 330°0 and 340°0 | 9 | | − 25°0 | 340°0 | − 20°0 and − 30°0 | 335°0 and 345°0 | 14 | | − 25°0 | 345°0 | − 20°0 and − 30°0 | 341°0 and 349°0 | 13 | | − 25°0 | 350°0 | − 20°0 and − 30°0 | 346°0 and 354°0 | 11 | | − 25°0 | 7°5 | − 20°0 and − 30°0 | 360°0 and 0°0 | 1 | | − 30°0 | 300°0 | − 27°0 and − 33°0 | 297°5 and 302°5 | 4 | | − 30°0 | 315°0 | − 27°5 and − 32°5 | 310°0 and 320°0 | 12 | | − 30°0 | 320°0 | − 25°0 and − 35°0 | 316°0 and 324°0 | 15 | ### Table VIII. (Continued.) | Intersections | Observations employed | Number of additional observations | Total number of observations | Mean Declination at the point of intersection | |---------------|-----------------------|----------------------------------|-----------------------------|---------------------------------------------| | Lat. | Long. | Between the Latitudes of | Between the Longitudes of | | | | | | | | | -30°0 | 335°0 | -26°0 and -34°0 | 330°0 and 340°0 | 2 | 10 | 9°06 | | -30°0 | 340°0 | -55°0 and -35°0 | 335°0 and 345°0 | ... | 16 | 12°13 | | -30°0 | 345°0 | -25°0 and -35°0 | 340°0 and 350°0 | 2 | 16 | 15°34 | | -30°0 | 350°0 | -25°0 and -35°0 | 345°0 and 355°0 | 2 | 12 | 18°40 | | -30°0 | 355°0 | -27°5 and -32°5 | 350°0 and 00°0 | 2 | 10 | 21°34 | | -30°0 | 0°0 | -28°0 and -32°0 | 358°0 and 02°0 | ... | 7 | 23°39 | | -30°0 | 10°0 | -25°0 and -35°0 | 5°0 and 15°0 | 1 | 18 | 27°22 | | -35°0 | 300°0 | -31°0 and -39°0 | 297°0 and 303°0 | ... | 16 | -13°15 | | -35°0 | 305°0 | -34°0 and -36°0 | 302°5 and 307°5 | 1 | 15 | -10°38 | | -35°0 | 310°0 | -30°0 and -40°0 | 307°5 and 312°5 | ... | 15 | -7°41 | | -35°0 | 325°0 | -31°0 and -39°0 | 320°0 and 330°0 | ... | 6 | 1°39 | | -35°0 | 335°0 | -30°0 and -40°0 | 330°0 and 340°0 | 2 | 11 | 7°44 | | -35°0 | 340°0 | -30°0 and -40°0 | 336°0 and 344°0 | ... | 11 | 10°47 | | -35°0 | 350°0 | -30°0 and -40°0 | 343°0 and 357°0 | 2 | 13 | 17°03 | | -35°0 | 355°0 | -30°0 and -40°0 | 351°0 and 359°0 | 2 | 10 | 19°51 | | -35°0 | 0°0 | -30°0 and -40°0 | 355°0 and 05°0 | ... | 18 | 22°31 | | -35°0 | 5°0 | -30°0 and -40°0 | 0°0 and 10°0 | 1 | 10 | 25°10 | | -35°0 | 10°0 | -32°0 and -38°0 | 6°0 and 14°0 | 2 | 14 | 26°50 | | -35°0 | 15°0 | -30°0 and -40°0 | 13°0 and 17°0 | ... | 22 | 27°50 | | -35°0 | 17°5 | -30°0 and -40°0 | 16°0 and 19°0 | ... | 16 | 28°51 | | -40°0 | 297°5 | -38°0 and -42°0 | 297°0 and 298°0 | 2 | 13 | -16°02 | | -40°0 | 300°0 | -37°0 and -43°0 | 298°0 and 302°0 | 2 | 15 | -14°30 | | -40°0 | 305°0 | -37°0 and -43°0 | 300°0 and 310°0 | ... | 14 | -12°13 | | -42°5 | 297°5 | -41°0 and -44°0 | 296°0 and 299°0 | 2 | 11 | -16°42 | | -42°5 | 300°0 | -40°0 and -45°0 | 298°5 and 301°0 | 2 | 9 | -15°17 | | -45°0 | 295°0 | -42°5 and -47°5 | 294°0 and 296°5 | 1 | 15 | -18°34 | | -47°5 | 292°5 | -45°0 and -50°0 | 292°0 and 293°0 | 2 | 14 | -20°00 | | -47°5 | 297°5 | -45°0 and -50°0 | 295°0 and 300°0 | 3 | 10 | -18°19 | | -50°0 | 292°5 | -47°0 and -53°0 | 291°5 and 293°0 | ... | 18 | -20°49 | | -50°0 | 295°0 | -47°5 and -52°5 | 294°0 and 296°5 | 3 | 12 | -20°15 | | -50°0 | 297°5 | -47°5 and -52°5 | 296°0 and 299°5 | 1 | 9 | -19°15 | | -50°0 | 10°0 | -47°0 and -53°0 | 5°0 and 15°0 | ... | 6 | -23°35 | | -52°5 | 290°0 | -50°0 and -55°0 | 289°5 and 290°0 | 4 | 14 | -22°48 | | -52°5 | 292°5 | -50°0 and -55°0 | 292°0 and 293°0 | 2 | 10 | -21°50 | | -52°5 | 295°0 | -50°0 and -55°0 | 291°0 and 299°0 | ... | 59 | -21°04 | | -52°5 | 297°5 | -50°0 and -55°0 | 295°0 and 300°0 | ... | 29 | -20°15 | | -52°5 | 300°0 | -51°0 and -54°0 | 299°0 and 301°0 | ... | 14 | -19°39 | | -52°5 | 302°5 | -50°0 and -55°0 | 301°0 and 304°0 | ... | 18 | -18°33 | | -55°0 | 290°0 | -54°0 and -56°0 | 289°0 and 291°0 | 1 | 8 | -23°41 | | -55°0 | 292°5 | -54°0 and -56°0 | 292°0 and 293°0 | 2 | 15 | -23°16 | | -55°0 | 295°0 | -54°0 and -56°0 | 294°0 and 296°0 | 1 | 18 | -22°31 | | -55°0 | 305°0 | -53°0 and -57°0 | 303°0 and 307°0 | ... | 13 | -18°17 | | -57°5 | 307°5 | -55°0 and -60°0 | 305°0 and 310°0 | ... | 9 | -18°25 | | -57°5 | 352°5 | -56°0 and -59°0 | 350°0 and 355°0 | ... | 6 | -10°58 | | -60°0 | 307°5 | -56°0 and -64°0 | 305°0 and 310°0 | ... | 12 | -19°31 | | -62°5 | 330°0 | -62°0 and -63°0 | 327°0 and 333°0 | ... | 4 | -5°50 | | -62°5 | 335°0 | -60°0 and -65°0 | 332°0 and 338°0 | ... | 6 | -2°32 | | -62°5 | 345°0 | -60°0 and -65°0 | 343°0 and 347°0 | ... | 7 | 4°20 | | -65°0 | 332°5 | -64°0 and -66°0 | 301°0 and 304°0 | ... | 18 | -23°23 | | -65°0 | 305°0 | -64°0 and -66°0 | 304°0 and 306°0 | 2 | 16 | -21°54 | | -65°0 | 317°5 | -64°0 and -66°0 | 316°0 and 319°0 | ... | 6 | -14°07 | | -65°0 | 350°0 | -60°0 and -70°0 | 348°0 and 352°0 | ... | 8 | 7°01 | | -67°5 | 347°5 | -65°0 and -70°0 | 345°0 and 350°0 | ... | 8 | 4°17 | | -70°0 | 345°0 | -69°0 and -71°0 | 343°0 and 347°0 | ... | 4 | 2°27 | General Table of the Declination in the Atlantic.—It may possibly be found convenient for the purposes of navigation, that the books which contain a compendium of the tables requisite to be used at sea, should include a general table of the magnetic Declination at a certain epoch for a convenient number of geographical positions, with auxiliary tables furnishing the means of readily computing the Declination for intermediate positions, and for other years. The subjoined Tables, Nos. IX. and X., have been formed for the purpose of supplying what has frequently appeared to me a desideratum in this respect. No. IX. is a general table of the Declination in the Atlantic for January 1840, at the intersection of every fifth degree of latitude and longitude between 60° north and 60° south latitude, taken from the maps which accompany this memoir. Should this table be adopted in future editions of any of the very useful compendiums referred to, auxiliary tables may be readily computed and added, containing the factors in longitude and latitude for facilitating the calculation of the Declination corresponding to intermediate geographical positions; whilst by means of Table X. the values of the Declinations in Table IX. may be adapted approximately to any other year for which the Declination may be required. The numbers which it contains are the values of the annual secular change of the Declination, which being multiplied by the interval of years from the date to which the table corresponds (i.e. January 1840), observing to prefix the sign + to the interval (in years) if the Declination is required for a subsequent year to 1840, or the sign — if required for an earlier year, will give the correction to be applied for the difference of epoch. The values of the secular change in Table X. are derived from the comparison of the maps which accompany this memoir with the map of the Declination in 1787, published originally (with the observations on which it was based) in Hansteen's Magnetismus der Erde, and republished in this country by myself in the Report of the British Association for the Advancement of Science in 1835. The table consequently represents the average annual secular change which has taken place in the fifty-three years antecedent to 1840. But it will be remembered that the secular change in any particular locality is by no means a constant quantity; and, although over a large proportion of the area of the Atlantic, there is reason to believe that the annual change is still continuing at a rate which does not materially differ from the average of the last fifty years, yet there are parts, (as for example, in the vicinity of the British Islands, and of the Cape of Good Hope,) where the secular change has latterly been obviously undergoing a considerable alteration. Tables formed as these have been, will therefore require to be reformed from time to time; the general table by fresh observations, and the table of secular change by a comparison of the maps founded on those observations with those now given. The time that may be allowed to elapse before the present tables are thus reformed will probably depend less on the interests of navigation and science, than on the degree of attention with which these interests may be regarded by the authorities of the Admiralty in times to come. But whenever it may be done, it may be expected that the observations of that period will be much more accordant with each other, and with nature, than those which have been at my disposal; in consequence of the general adoption, that we may reasonably anticipate will then have taken place, of the practice of correcting for the deviation in the pointing of the compass occasioned by the ship's iron, and which the increased employment of iron in the equipment of vessels and the magnitude of the errors occasioned thereby, already render in a great number of instances absolutely indispensable. Those who know, as matter of history, the difficulties with which the first introduction of lunar observations and chronometers had to contend, can confidently look forward to a period when the practice of correcting the errors of the compass shall have become general amongst naval officers at least, if not, as may be hoped, amongst merchant seamen also; especially since in the form in which the corrections are now placed, no other preliminary knowledge is required for this purpose than that of the four first rules in arithmetic, with due attention to the signs by which the errors and corrections are characterised. Table IX.—General Table of the Magnetic Declination for January 1840 in the Atlantic Ocean, at the intersection of every 5° of Latitude and Longitude, between 60° North and 60° South Latitude. | Lat. | 280° | 285° | 290° | 295° | 300° | 305° | 310° | 315° | 320° | 325° | 330° | 335° | 340° | 345° | 350° | 355° | 0° | 5° | 10° | 15° | 20° | |------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|----|----|----|----|----| | 60 | | | | | | | | | | | | | | | | | | | | | | | 55 | | | | | | | | | | | | | | | | | | | | | | | 50 | | | | | | | | | | | | | | | | | | | | | | | 45 | | | | | | | | | | | | | | | | | | | | | | | 40 | | | | | | | | | | | | | | | | | | | | | | | 35 | | | | | | | | | | | | | | | | | | | | | | | 30 | | | | | | | | | | | | | | | | | | | | | | | 25 | | | | | | | | | | | | | | | | | | | | | | | 20 | | | | | | | | | | | | | | | | | | | | | | | 15 | | | | | | | | | | | | | | | | | | | | | | | 10 | | | | | | | | | | | | | | | | | | | | | | | 5 | | | | | | | | | | | | | | | | | | | | | | | 0 | | | | | | | | | | | | | | | | | | | | | | | -5 | | | | | | | | | | | | | | | | | | | | | | | -10 | | | | | | | | | | | | | | | | | | | | | | | -15 | | | | | | | | | | | | | | | | | | | | | | | -20 | | | | | | | | | | | | | | | | | | | | | | | -25 | | | | | | | | | | | | | | | | | | | | | | | -30 | | | | | | | | | | | | | | | | | | | | | | | -35 | | | | | | | | | | | | | | | | | | | | | | | -40 | | | | | | | | | | | | | | | | | | | | | | | -45 | | | | | | | | | | | | | | | | | | | | | | | -50 | | | | | | | | | | | | | | | | | | | | | | | -55 | | | | | | | | | | | | | | | | | | | | | | | -60 | | | | | | | | | | | | | | | | | | | | | | | -65 | | | | | | | | | | | | | | | | | | | | | | | -70 | | | | | | | | | | | | | | | | | | | | | | The Declinations marked thus † are interpolated in the absence of observations. East Declination is characterised by the sign —. Where no sign is prefixed the Declination is West. TABLE X.—Annual Secular Change in the Magnetic Declination, on the average of fifty-three years antecedent to January 1840, taken to the nearest half-minute. The sign + in this table implies that the secular change in the period referred to was increasing westerly, or decreasing easterly Declination; and the sign — implies the change to have been decreasing westerly, or increasing easterly Declination. | Lat. | 280° | 285° | 290° | 295° | 300° | 305° | 310° | 315° | 320° | 325° | 330° | 335° | 340° | 345° | 350° | 355° | 360° | 365° | 370° | 375° | 380° | 385° | 390° | 395° | 400° | |------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| | 60° | +2.0 | +6.6 | +12.3 | +14.0 | +18.3 | +12.5 | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | +... | | 55° | -5.7 | -2.3 | +2.6 | +5.7 | +9.3 | +10.0 | +9.3 | +9.4 | +8.2 | +6.5 | +6.5 | +4.0 | +4.0 | +3.7 | +3.7 | +2.3 | +2.3 | +0.5 | +0.5 | +0.5 | +0.5 | +0.5 | +0.5 | +0.5 | | 50° | -4.5 | -0.6 | +1.2 | +5.4 | +9.2 | +11.0 | +10.5 | +11.0 | +8.5 | +7.5 | +7.5 | +5.5 | +5.5 | +4.0 | +4.0 | +2.0 | +2.0 | +0.0 | +0.0 | +0.0 | +0.0 | +0.0 | +0.0 | +0.0 | | 45° | -4.0 | -2.0 | +0.0 | +2.2 | +4.5 | +6.2 | +7.0 | +7.8 | +8.2 | +8.0 | +7.0 | +7.0 | +5.5 | +5.5 | +4.1 | +4.1 | +2.7 | +2.7 | +0.0 | +0.0 | +0.0 | +0.0 | +0.0 | +0.0 | | 40° | -0.0 | +1.5 | +2.8 | +3.6 | +4.0 | +5.0 | +5.5 | +6.0 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | +6.4 | | 35° | +0.5 | +1.5 | +2.5 | +3.5 | +4.0 | +4.5 | +5.0 | +5.5 | +6.0 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | | 30° | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | +2.0 | | 25° | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | +2.5 | | 20° | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | +3.0 | | 15° | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | +3.5 | | 10° | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | +4.0 | | 5° | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | +4.5 | | 0° | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | +5.0 | | -5° | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | +5.5 | | -10° | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | +6.0 | | -15° | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | +6.5 | | -20° | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | +7.0 | | -25° | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | +7.5 | | -30° | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | +8.0 | | -35° | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | +8.5 | | -40° | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | +9.0 | | -45° | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | +9.5 | | -50° | +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| +10.0| | -55° | +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| +10.5| | -60° | +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| +11.0| Comparison with M. Gauss's Theory.—As many persons may be desirous of seeing the result of a comparison of the Declinations computed by M. Gauss's general theory, with those derived from observation over a field of considerable extent, I have subjoined in Table XI. in degrees and decimals of a degree, the differences of Declination at the intersections of every five degrees of latitude and longitude. The sign — signifies that the theoretical Declinations are more easterly (i.e. greater east or less west Declination) than the observed; and the sign + that the theoretical are more westerly (i.e. greater west or less east Declination) than the observed. It must be remembered that the coefficients of M. Gauss's theory in their present numerical values do not profess to be more than a first approximation; that they rest on maps of the phenomena drawn indeed from observation, but in which care was not always taken to use only observations of a definite epoch; that the points of the globe in which the elements of the theory rest upon the observed phenomena are only eighty-four points on the whole surface of the globe, viz. twelve points on seven parallels; no point being taken in a more southern parallel than 20° south latitude; and lastly, that the coefficients are limited to terms of the fourth order. On the other hand, it will be remembered that the Declination is the easiest, and has been by far the most frequently observed, of the three magnetic elements; that from a very early period maps of the Declination, particularly in the Atlantic, and professing to be adapted to definite epochs, have been in much request on account of their use in navigation; and that consequently it might naturally be expected that the differences between the theory and observation should be less in the comparison here instituted, than might be the case in parts of the globe where the elements of the theory have had a less direct, or a less satisfactory derivation. The differences of greatest amount which appear in this comparison are those over the north-west portion of the Atlantic, amounting to from five to nearly eight degrees generally between the meridian of Newfoundland and the United States, (meridians of 287° to 307°, or 53° to 73° west longitude), in the well-traversed parallels from 45° to 50° N.; and increasing to 18° and upwards in the latitude of 60° in the vicinity of Hudson's Strait, where the correct value of the declination has been well known for several years by the observations of the different British expeditions of discovery. In the southern Atlantic, where, as already remarked, the data of observation on which the theoretical coefficients are based have not been taken from a higher latitude than 20° S., there appears a tendency to systematic differences; in excess (or too small easterly declinations) on the west side of the Atlantic, and in defect (or too small westerly declinations) on the east side of the Atlantic. A discrepancy deserving of notice in the theoretical lines (i.e in the lines of magnetic Declination as they may be drawn from calculation with the present numerical elements of M. Gauss's theory), is in the value of the remarkable isogonic line, the ### Table XI—Comparison with M. Gauss's Theory. The sign — signifies that the theoretical Declinations are more easterly (or less westerly) than the observed; and the sign + that they are more westerly (or less easterly) than the observed Declinations. | Lat. | 285° | 290° | 295° | 300° | 305° | 310° | 315° | 320° | 325° | 330° | 335° | 340° | 345° | 350° | 355° | 360° | 365° | 370° | 375° | 380° | 385° | 390° | 395° | 400° | |------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------|------| | 60° | -188 | -183 | -180 | -176 | -172 | -168 | -164 | -160 | -156 | -152 | -148 | -144 | -140 | -136 | -132 | -128 | -124 | -120 | -116 | -112 | -108 | -104 | -100 | -96 | | 55° | -107 | -102 | -97 | -92 | -87 | -82 | -77 | -72 | -67 | -62 | -57 | -52 | -47 | -42 | -37 | -32 | -27 | -22 | -17 | -12 | -7 | -2 | 3 | 8 | | 50° | -62 | -57 | -52 | -47 | -42 | -37 | -32 | -27 | -22 | -17 | -12 | -7 | -2 | 3 | 8 | 13 | 18 | 23 | 28 | 33 | 38 | 43 | 48 | 53 | | 45° | -18 | -13 | -8 | -3 | 2 | 7 | 12 | 17 | 22 | 27 | 32 | 37 | 42 | 47 | 52 | 57 | 62 | 67 | 72 | 77 | 82 | 87 | 92 | 97 | | 40° | -14 | -9 | -4 | -1 | 2 | 7 | 12 | 17 | 22 | 27 | 32 | 37 | 42 | 47 | 52 | 57 | 62 | 67 | 72 | 77 | 82 | 87 | 92 | 97 | | 35° | -12 | -7 | -2 | 3 | 8 | 13 | 18 | 23 | 28 | 33 | 38 | 43 | 48 | 53 | 58 | 63 | 68 | 73 | 78 | 83 | 88 | 93 | 98 | 103 | | 30° | -6 | -1 | 4 | 9 | 14 | 19 | 24 | 29 | 34 | 39 | 44 | 49 | 54 | 59 | 64 | 69 | 74 | 79 | 84 | 89 | 94 | 99 | 104 | 109 | | 25° | -4 | -1 | 3 | 8 | 13 | 18 | 23 | 28 | 33 | 38 | 43 | 48 | 53 | 58 | 63 | 68 | 73 | 78 | 83 | 88 | 93 | 98 | 103 | 108 | | 20° | -2 | -1 | 1 | 6 | 11 | 16 | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | | 15° | -1 | 1 | 6 | 11 | 16 | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | | 10° | 1 | 6 | 11 | 16 | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | | 5° | 6 | 11 | 16 | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | | 0° | 11 | 16 | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | | -5° | 16 | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | | -10° | 21 | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | | -15° | 26 | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | | -20° | 31 | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | | -25° | 36 | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | | -30° | 41 | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | | -35° | 46 | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | 161 | | -40° | 51 | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | 161 | 166 | | -45° | 56 | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | 161 | 166 | 171 | | -50° | 61 | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | 161 | 166 | 171 | 176 | | -55° | 66 | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | 161 | 166 | 171 | 176 | 181 | | -60° | 71 | 76 | 81 | 86 | 91 | 96 | 101 | 106 | 111 | 116 | 121 | 126 | 131 | 136 | 141 | 146 | 151 | 156 | 161 | 166 | 171 | 176 | 181 | 186 | MDCCCXLIX. branches of which form the limits of the four great systems of isogonic lines, viz. of the four great systems which prevail respectively in the N.W., N.E., S.W. and S.E. directions, and have one isogonic line common to them all, the branches of which meet at a common point of junction or intersection near the west coast of Africa, and not far from the terrestrial equator. The theoretical value of this line is $22^\circ 13'$ W.; whereas its true value is certainly not more than between $19^\circ$ and $20^\circ$, and it appears to have been in the year 1840 nearly midway between those values. Had the theo- retical value been in defect instead of in excess, the difference might have been ascribed to an effect of secular change; in which case M. Gauss's map might be supposed to represent an earlier state of the phenomena than that of the year 1840. But the fact is otherwise; the theoretical value of the line in question is in excess, although its actual value has been progressively increasing since the earliest record of the phenomena, and was greater in 1848 than in any antecedent year since the phenomena have been observed. The theoretical error is the more remarkable because Mr. Barlow's map for 1833, which was the one employed by M. Gauss for the declination, gives the value of that element correctly at $20^\circ$ or thereabouts, at the spot where M. Gauss's theoretical line of $22^\circ 13'$ cuts the coast of Africa. The form of the lines in Mr. Barlow's map in that quarter of the globe is indeed not correct, since on no part of the surface of the earth do the magnetic lines fork in the manner there represented, and which is very different from the intersection of lines of equal value forming four branches of one and the same isogonic line, which is the character of the remarkable line now referred to; but the value of the declina- tion on that part of the African coast is more correct in Mr. Barlow's map than in M. Gauss's theory, which is partly based upon it. The geographical position of the intersection is also given by M. Gauss's theory about $10^\circ$ of longitude too much to the east. The secular movement of the intersection is to the west, and may be estimated, very roughly, at about $10^\circ$ in the last half-century. It is obvious from this comparison that the General Theory will require to have its numerical coefficients reconstructed before it can become available for practical purposes; and that those who desire to take a correct view of the magnetic phenomena, must for the present at least, have recourse to the maps constructed directly from the observations themselves. ### Table XII.—Declinations employed in the Map, corrected to the epoch of January 1840. † in the column of remarks signifies that the Declination has been corrected for the effect of the ship's iron. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | **Between the latitudes of 65° and 60°.** | | 63° 18' | 280° 41' | 1846. Moore. | 58° 21' | -1° 24' | 56° 57' | At sea†. | | 63° 13 | 282° 55 | 1846. Moore. | 55° 28' | -1° 24' | 54° 31' | At sea†. | | 63° 15 | 284° 41 | 1846. Moore. | 58° 54' | -1° 24' | 57° 30' | At sea†. | | 63° 19 | 285° 40 | 1846. Moore. | 60° 13' | -1° 24' | 58° 49' | At sea†. | | 62° 57 | 287° 13 | 1846. Moore. | 58° 56' | -1° 24' | 57° 32' | At sea†. | | 62° 47 | 288° 27 | 1846. Moore. | 58° 20' | -1° 24' | 56° 56' | At sea†. | | 61° 54 | 289° 40 | 1846. Moore. | 54° 49' | -1° 24' | 53° 25' | At sea†. | | 62° 13 | 290° 47 | 1846. Moore. | 59° 20' | -1° 24' | 57° 56' | At sea†. | | 61° 00 | 294° 48 | 1846. Moore. | 55° 56' | -1° 24' | 54° 32' | At sea†. | | 61° 34 | 295° 46 | 1846. Moore. | 58° 33' | -1° 24' | 57° 09' | At sea†. | | 60° 49 | 296° 00 | 1846. Moore. | 56° 22' | -1° 24' | 54° 58' | At sea†. | | 60° 58 | 299° 00 | 1846. Moore. | 55° 49' | -1° 24' | 54° 25' | At sea†. | | 64° 08 | 338° 05 | 1836. Lottin. | 43° 14' | +0° 22' | 43° 36' | Reikiavik. | | 62° 00 | 354° 02 | 1831. Vidal. | 30° 50' | +0° 17' | 31° 07' | Thorshavn. | | 60° 09 | 358° 53 | 1838. Ross. | 27° 09' | +0° 03' | 27° 12' | Lerwick. | | 60° 45 | 359° 14 | 1831. Vidal. | 28° 38' | +0° 17' | 28° 55' | Balta Island. | | **Between the latitudes of 60° and 50°.** | | 51° 15 | 279° 04 | 1846. Moore. | 12° 40' | +0° 18' | 12° 58' | Moose Factory. | | 51° 18 | 279° 16 | 1846. Moore. | 10° 55' | +0° 18' | 11° 13' | On shore, entrance of Moose Harbour. | | 51° 28 | 279° 26 | 1846. Moore. | 10° 41' | +0° 18' | 10° 59' | At sea†. | | 51° 49 | 279° 28 | 1846. Moore. | 10° 05' | +0° 18' | 10° 23' | At sea†. | | 50° 13 | 293° 35 | 1831. Bayfield. | 23° 34' | +0° 36' | 24° 10' | Bay of Seven Islands. | | 50° 11 | 293° 55 | 1831. Bayfield. | 24° 08' | +0° 36' | 24° 44' | Moisie River. | | 50° 17 | 295° 58 | 1831. Bayfield. | 25° 30' | +0° 51' | 26° 21' | Mingan Harbour. | | 50° 03 | 296° 07 | 1842. Lefroy. | 26° 26' | -0° 15' | 26° 05' | At sea†. | | 50° 14 | 296° 49 | 1832. Bayfield. | 27° 31' | +0° 50' | 28° 21' | Betchewun Harbour. | | 50° 14 | 297° 48 | 1832. Bayfield. | 28° 08' | +0° 52' | 29° 00' | Nabosippe River. | | 50° 11 | 298° 44 | 1832. Bayfield. | 28° 47' | +1° 00' | 29° 47' | Kegashka Bay. | | 50° 11 | 299° 52 | 1832. Bayfield. | 29° 22' | +1° 00' | 30° 22' | Cape Whittle. | | 50° 33 | 300° 43 | 1833. Bayfield. | 29° 33' | +0° 55' | 30° 28' | Little Mecattina. | | 50° 44 | 300° 59 | 1833. Bayfield. | 30° 00' | +0° 58' | 31° 00' | Grand Mecattina. | | 51° 16 | 301° 47 | 1834. Bayfield. | 31° 15' | +0° 55' | 32° 10' | Mistanoque Harbour. | | 51° 27 | 302° 33 | 1834. Bayfield. | 32° 00' | +0° 56' | 32° 56' | Belles Amours Harbour. | | 51° 28 | 302° 45 | 1834. Bayfield. | 32° 30' | +0° 59' | 33° 29' | Bradore Harbour. | | 51° 28 | 303° 03 | 1833. Bayfield. | 32° 26' | +1° 05' | 33° 41' | Forteaw Bay. | | 59° 55 | 303° 20 | 1846. Moore. | 52° 29' | -1° 24' | 51° 05' | At sea†. | | 51° 24 | 303° 26 | 1833. Bayfield. | 33° 30' | +1° 05' | 34° 35' | Green Island in Straits of Bellisle. | | 51° 44 | 303° 34 | 1835. Bayfield. | 34° 30' | +0° 47' | 35° 17' | Red Bay. | | 52° 00 | 304° 09 | 1835. Bayfield. | 35° 30' | +0° 48' | 36° 18' | Chateau Bay. | | 52° 21 | 304° 21 | 1835. Bayfield. | 37° 30' | +0° 50' | 38° 20' | Cape St. Lewis. | | 58° 46 | 307° 00 | 1846. Moore. | 50° 05' | -1° 21' | 48° 44' | At sea†. | | 56° 49 | 310° 26 | 1846. Moore. | 45° 45' | -1° 15' | 44° 30' | At sea†. | | 57° 54 | 310° 34 | 1846. Moore. | 48° 45' | -1° 15' | 47° 30' | At sea†. | | 57° 42 | 315° 57 | 1846. Moore. | 47° 44' | -1° 15' | 46° 29' | At sea†. | | 54° 00 | 316° 24 | Sept. 1846. Moore. | 44° 00' | -1° 16' | 42° 44' | At sea†. | | 57° 30 | 319° 20 | 1846. Moore. | 45° 28' | -1° 11' | 44° 17' | At sea†. | | 57° 21 | 321° 05 | 1846. Moore. | 44° 33' | -1° 11' | 43° 22' | At sea†. | | 52° 17 | 321° 45 | Sept. 1846. Moore. | 39° 18' | -1° 14' | 38° 04' | At sea†. | * A mean of 4 stations. ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-----------|-----------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | 57° 05' | 324° 10' | 1846. Moore. | 43° 16' | -1° 03' | 42° 11' | At sea†. | | 51° 47' | 325° 00' | Sept. 1846. Moore. | 37° 40' | -1° 08' | 36° 32' | At sea†. | | 51° 10' | 327° 09' | Sept. 1846. Moore. | 37° 43' | -1° 00' | 36° 43' | At sea†. | | 56° 25' | 327° 15' | 1846. Moore. | 40° 19' | -0° 45' | 39° 34' | At sea†. | | 56° 15' | 329° 18' | 1846. Moore. | 40° 14' | -0° 45' | 39° 29' | At sea†. | | 50° 14' | 330° 46' | Sept. 1846. Moore. | 35° 55' | -0° 53' | 35° 02' | At sea†. | | 56° 16' | 333° 02' | 1846. Moore. | 38° 18' | -0° 26' | 37° 52' | At sea†. | | 56° 00' | 335° 06' | 1846. Moore. | 36° 52' | -0° 26' | 36° 26' | At sea†. | | 55° 41' | 336° 55' | 1846. Moore. | 36° 26' | -0° 26' | 36° 00' | At sea†. | | 55° 53' | 337° 05' | 1846. Moore. | 35° 32' | -0° 26' | 35° 06' | At sea†. | | 56° 09' | 338° 25' | 1846. Moore. | 36° 20' | -0° 26' | 35° 54' | At sea†. | | 56° 19' | 341° 08' | 1846. Moore. | 34° 19' | -0° 22' | 33° 57' | At sea†. | | 57° 43' | 345° 08' | 1846. Moore. | 32° 14' | -0° 16' | 31° 58' | At sea†. | | 58° 40' | 349° 09' | 1846. Moore. | 31° 35' | -0° 13' | 31° 22' | At sea†. | | 51° 56' | 349° 43' | Oct. 1838. Ross. | 28° 42' | -0° 06' | 28° 36' | Valencia Island. | | 52° 02' | 350° 30' | Oct. 1838. Ross. | 28° 11' | -0° 06' | 28° 05' | Killarney. | | 53° 48' | 350° 31' | Nov. 1838. Ross. | 29° 09' | -0° 06' | 29° 03' | Westport. | | 52° 40' | 351° 24' | Oct. 1838. Ross. | 28° 03' | -0° 06' | 27° 57' | Limerick. | | 57° 49' | 351° 28' | Oct. 1831. Vidal. | 30° 30' | -0° 34' | 29° 56' | St. Kilda. | | 51° 54' | 351° 32' | Oct. 1838. Ross. | 27° 44' | -0° 06' | 27° 38' | Cork. | | 54° 14' | 351° 32' | Nov. 1838. Ross. | 29° 15' | -0° 06' | 29° 09' | Markree. | | 53° 14' | 352° 07' | Oct. 1838. Ross. | 28° 03' | -0° 06' | 27° 57' | Shannon Harbour. | | 53° 42' | 352° 27' | Nov. 1838. Ross. | 28° 08' | -0° 06' | 28° 02' | Edgeworthstown. | | 55° 08' | 352° 35' | 1831. Vidal. | 28° 28' | -0° 06' | 28° 22' | Buncrana. | | 54° 59' | 352° 41' | Nov. 1838. Ross. | 28° 47' | -0° 06' | 28° 41' | Londonderry. | | 52° 15' | 352° 52' | Oct. 1838. Ross. | 26° 44' | -0° 06' | 26° 38' | Waterford. | | 54° 21' | 353° 21' | Nov. 1838. Ross. | 28° 08' | -0° 06' | 28° 02' | Armagh. | | 58° 15' | 353° 36' | 1846. Otter. | 27° 40' | -0° 06' | 27° 34' | Stormaway. | | 53° 21' | 353° 45' | Oct. 1838. Ross. | 27° 35' | -0° 06' | 27° 29' | Dublin. | | 53° 21' | 353° 45' | Jan. 1840. Lloyd. | 27° 30' | 0° 00' | 27° 30' | Dublin Observatory. | | 59° 05' | 353° 53' | 1831. Vidal. | 29° 41' | -0° 34' | 29° 07' | Sulisker. | | 59° 07' | 354° 13' | 1831. Vidal. | 29° 34' | -0° 34' | 29° 00' | Rona. | | 58° 09' | 354° 46' | 1848. Otter. | 27° 59' | +0° 42' | 28° 41' | Loch Inver. | | 58° 23' | 354° 56' | 1846. Otter. | 27° 34' | +0° 42' | 28° 16' | Luxford. | | 58° 15' | 354° 57' | 1846. Otter. | 27° 58' | +0° 42' | 28° 40' | Gowan. | | 50° 09' | 355° 09' | 1831. Austin. | 25° 25' | -0° 42' | 24° 43' | Pendennis Castle. | | 57° 28' | 355° 49' | Aug. 1838. Ross. | 27° 59' | -0° 06' | 27° 53' | Inverness. | | 57° 58' | 356° 03' | Aug. 1838. Ross. | 27° 55' | -0° 06' | 27° 49' | Golspie. | | 58° 24' | 356° 55' | Aug. 1838. Ross. | 27° 41' | -0° 06' | 27° 35' | Wick. | | 59° 00' | 357° 02' | Aug. 1838. Ross. | 27° 47' | -0° 06' | 27° 41' | Kirkwall. | | 54° 55' | 357° 16' | Sept. 1838. Ross. | 26° 15' | -0° 06' | 26° 09' | Carlisle. | | 55° 35' | 357° 29' | Jan. 1842. Brisbane. | 25° 27' | +0° 10' | 25° 37' | Makerstoun Observatory. | | 58° 16' | 357° 49' | 1846. Moore. | 26° 43' | +0° 42' | 27° 25' | At sea†. | | 57° 09' | 357° 55' | July 1838. Ross. | 26° 41' | -0° 06' | 26° 35' | Aberdeen. | | 54° 58' | 358° 24' | Aug. 1838. Ross. | 25° 20' | -0° 06' | 25° 14' | Newcastle. | | 52° 57' | 358° 52' | May 1838. Ross. | 24° 53' | -0° 06' | 24° 47' | Nottingham. | | 53° 57' | 358° 54' | April 1838. Ross. | 25° 09' | -0° 06' | 25° 03' | York. | | 54° 18' | 359° 34' | May 1838. Ross. | 24° 32' | -0° 06' | 24° 26' | Scarborough. | | 54° 08' | 359° 46' | May 1838. Ross. | 24° 39' | -0° 06' | 24° 33' | Bridlington. | | 51° 31' | 359° 38' | April 1838. Ross. | 23° 59' | -0° 06' | 23° 53' | Bushey. | | 53° 19' | 0° 00' | May 1838. Ross. | 24° 26' | -0° 06' | 24° 20' | Louth. | | 51° 28' | 0° 00' | 1841. Airy. | 23° 16' | +0° 07' | 23° 23' | Greenwich Observatory. | | 51° 56' | 1° 13' | May 1838. Ross. | 23° 08' | -0° 06' | 23° 12' | Harwich. | | 52° 56' | 1° 19' | May 1838. Ross. | 23° 21' | -0° 06' | 23° 15' | Cromer. | | 51° 23' | 1° 23' | April 1838. Ross. | 22° 54' | -0° 06' | 22° 48' | Margate. | | 52° 28' | 1° 50' | May 1838. Ross. | 23° 00' | -0° 06' | 22° 54' | Lowestoffe. | | 50° 51' | 4° 22' | Jan. 1844. Quetelet. | 21° 16' | +0° 32' | 21° 48' | Brussels. | | 59° 54' | 10° 44' | Jan. 1840. Hansteen. | 19° 50' | 0° 00' | 19° 50' | Christiania. | ### TABLE XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|-----------------------|------------------------|-----------------------------------------------| | | | | | | | | Between the latitudes of 50° and 40°. | | 43° 40′ | 280° 38′ | Jan. 1840. | Riddell. | 1° 27′ | 0° 00′ | 1° 27′ | Magnetic Observatory, Toronto. | | 45° 36′ | 283° 07′ | May 1843. | Lefroy. | 5° 11′ | +0° 05′ | 5° 16′ | Fort Portage. | | 45° 29′ | 284° 12′ | May 1843. | Lefroy. | 6° 58′ | +0° 05′ | 7° 03′ | 6 miles below Bytown. | | 40° 08′ | 284° 17′ | May 1846. | U.S. Coast Survey. | 4° 22′ | -0° 04′ | 4° 18′ | Whitehill. | | 40° 05′ | 284° 26′ | June 1846. | U.S. Coast Survey. | 3° 13′ | -0° 04′ | 3° 09′ | Fort Delaware. | | 45° 37′ | 284° 48′ | May 1843. | Lefroy. | 6° 58′ | +0° 05′ | 7° 03′ | Alfred Township. | | 45° 37′ | 285° 05′ | May 1843. | Lefroy. | 7° 28′ | +0° 05′ | 7° 33′ | Point aux Chênes. | | 45° 36′ | 285° 28′ | May 1843. | Lefroy. | 8° 41′ | +0° 05′ | 8° 46′ | Carillon. | | 45° 36′ | 285° 38′ | May 1843. | Lefroy. | 8° 26′ | +0° 05′ | 8° 31′ | On the Ottawa. | | 40° 43′ | 285° 59′ | 1844. | Renwick. | 6° 13′ | -0° 02′ | 6° 11′ | Columbia College. | | 40° 28′ | 286° 00′ | Jan. 1844. | U.S. Coast Survey. | 5° 51′ | -0° 02′ | 5° 49′ | Sandy Harbour. | | 45° 30′ | 286° 25′ | 1842. | Lefroy. | 8° 58′ | 0° 00′ | 8° 58′ | Montreal. | | 45° 32′ | 286° 26′ | 1834. | Bayfield. | 8° 00′ | 0° 00′ | 8° 00′ | Montreal. | | 40° 53′ | 286° 29′ | 1844. | Renwick. | 6° 54′ | -0° 02′ | 6° 52′ | Oyster Bay. | | 45° 00′ | 286° 39′ | Oct. 1845. | Boundary Survey. | 11° 28′ | 0° 00′ | 11° 28′ | Rouse's Point. | | 45° 19′ | 286° 42′ | 1842. | Lefroy. | 11° 22′ | 0° 00′ | 11° 22′ | St. John's. | | 46° 06′ | 286° 59′ | 1830. | Bayfield. | 10° 30′ | 0° 00′ | 10° 30′ | Stone Island. | | 46° 03′ | 287° 00′ | 1830. | Bayfield. | 11° 00′ | 0° 00′ | 11° 00′ | Sorel. | | 46° 03′ | 287° 00′ | 1842. | Lefroy. | 11° 23′ | 0° 00′ | 11° 23′ | Sorel. | | 41° 15′ | 287° 05′ | Sept. 1845. | U.S. Coast Survey. | 6° 17′ | -0° 06′ | 6° 11′ | Newhaven. | | 46° 14′ | 287° 16′ | 1828. | Bayfield. | 11° 15′ | +0° 06′ | 11° 21′ | Lake St. Peter. | | 46° 17′ | 287° 18′ | 1835. | Bayfield. | 10° 53′ | +0° 02′ | 10° 55′ | Point du Lac. | | 44° 16′ | 287° 23′ | 1829–1830. | Graham. | 12° 26′ | +0° 10′ | 12° 36′ | Montpelier. | | 46° 19′ | 287° 24′ | 1842. | Lefroy. | 11° 58′ | -0° 10′ | 11° 57′ | Three Rivers. | | 45° 53′ | 287° 26′ | 1842. | Lefroy. | 12° 28′ | -0° 01′ | 12° 27′ | Drummondville. | | 46° 25′ | 287° 36′ | 1835. | Bayfield. | 12° 52′ | +0° 02′ | 12° 54′ | Isle Bigôt. | | 41° 06′ | 287° 38′ | 1845. | Renwick. | 7° 14′ | -0° 06′ | 7° 08′ | Sandy Point. | | 45° 00′ | 287° 47′ | Nov. 1845. | Boundary Survey. | 11° 33′ | 0° 00′ | 11° 33′ | Stanstead. | | 44° 02′ | 287° 55′ | Sept. 1830. | Graham. | 7° 32′ | +0° 10′ | 7° 42′ | Haverhill. | | 43° 56′ | 288° 05′ | Sept. 1830. | Graham. | 9° 08′ | +0° 10′ | 9° 18′ | Warren. | | 41° 20′ | 288° 05′ | 1842. | U.S. Coast Survey. | 7° 38′ | -0° 06′ | 7° 32′ | Stonington. | | 46° 40′ | 288° 06′ | Aug 1845. | Bayfield. | 12° 52′ | +0° 02′ | 12° 54′ | Platon Point. | | 43° 49′ | 288° 07′ | Sept. 1830. | Graham. | 9° 38′ | +0° 10′ | 9° 48′ | West Rumney. | | 43° 45′ | 288° 18′ | Sept. 1830. | Graham. | 8° 32′ | +0° 10′ | 8° 42′ | Plymouth. | | 45° 01′ | 288° 30′ | Dec. 1845. | Graham. | 12° 22′ | 0° 00′ | 12° 22′ | Canaan Corner. | | 44° 43′ | 288° 31′ | Sept. 1830. | Graham. | 7° 53′ | +0° 10′ | 8° 03′ | Lake Winnissiiogee. | | 46° 49′ | 288° 44′ | 1842. | Lefroy. | 14° 12′ | -0° 02′ | 14° 10′ | Quebec, Artillery Barracks. | | 45° 15′ | 288° 46′ | May 1845. | Boundary Survey. | 12° 17′ | -0° 17′ | 12° 00′ | Prospect Hill. | | 46° 49′ | 288° 47′ | 1831–1836. | Bayfield. | 14° 14′ | +0° 06′ | 14° 20′ | Quebec, Wolfe's Monument. | | 45° 15′ | 288° 47′ | Oct. 1845. | Boundary Survey. | 12° 00′ | -0° 18′ | 11° 42′ | Observatory, Connecticut River. | | 42° 23′ | 288° 52′ | 1840. | Lowering and Bond. | 9° 18′ | 0° 00′ | 9° 18′ | Observatory, Cambridge, U.S. | | 45° 18′ | 288° 55′ | June 1845. | Boundary Survey. | 13° 20′ | -0° 17′ | 13° 03′ | Near the Highland Boundary Line. | | 41° 19′ | 288° 59′ | 1844. | Renwick. | 7° 29′ | -0° 05′ | 7° 24′ | Croton Point. | | 45° 20′ | 289° 05′ | June 1845. | Boundary Survey. | 13° 30′ | -0° 17′ | 13° 13′ | Arnold's River. | | 41° 38′ | 289° 05′ | Aug. 1845. | U.S. Coast Survey. | 8° 57′ | -0° 08′ | 8° 49′ | Fort Point. | | 45° 26′ | 289° 12′ | July 1845. | Boundary Survey. | 13° 10′ | -0° 17′ | 12° 53′ | Dead River. | | 41° 28′ | 289° 14′ | Aug. 1846. | U.S. Coast Survey. | 9° 10′ | -0° 10′ | 9° 00′ | Tarpaulin Town. | | 43° 05′ | 289° 15′ | July 1844. | Boundary Survey. | 9° 47′ | -0° 14′ | 9° 33′ | Boiling Rock. | | 45° 30′ | 289° 16′ | Oct. 1844. | Boundary Survey. | 13° 20′ | -0° 17′ | 13° 03′ | Near the Highland Boundary. | | 45° 32′ | 289° 18′ | Sept. 1844. | Boundary Survey. | 13° 30′ | -0° 16′ | 13° 14′ | Near the Highland Boundary. | | 45° 37′ | 289° 23′ | Sept. 1844. | Boundary Survey. | 13° 37′ | -0° 16′ | 13° 21′ | Near the Highland Boundary. | | 41° 29′ | 289° 24′ | Aug. 1846. | U.S. Coast Survey. | 8° 50′ | -0° 10′ | 8° 40′ | Indian Hill. | | 47° 08′ | 289° 28′ | 1842. | Lefroy. | 14° 00′ | -0° 04′ | 13° 56′ | At sea†. | | 47° 04′ | 289° 28′ | 1831. | Bayfield. | 14° 28′ | +0° 19′ | 14° 47′ | Crane Island. | | 45° 42′ | 289° 32′ | Sept. 1844. | Boundary Survey. | 13° 50′ | -0° 16′ | 13° 34′ | On the Highland Boundary. | | 47° 25′ | 289° 34′ | 1831. | Bayfield. | 15° 17′ | +0° 19′ | 15° 36′ | Isle aux Condres. | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | 45° 39′ | 289° 36′ | Aug. 1844. | Boundary Survey. | 14° 07′ | −0° 16′ | 13° 51′ | Taschereau's. | | 47° 12′ | 289° 38′ | 1831. | Bayfield. | 14° 49′ | +0° 19′ | 15° 08′ | Stone Pillar. | | 47° 20′ | 289° 42′ | 1842. | Lefroy. | 14° 16′ | −0° 06′ | 14° 10′ | At sea†. | | 42° 03′ | 289° 48′ | Sept. 1835. | Graham. | 9° 20′ | +0° 11′ | 9° 31′ | Provincetown. | | 46° 25′ | 289° 57′ | Nov. 1844. | Boundary Survey. | 15° 02′ | −0° 17′ | 14° 45′ | Astron. Station, S.W. branch of the St. John's River. | | 48° 09′ | 290° 16′ | 1829. | Bayfield. | 17° 35′ | +0° 24′ | 17° 59′ | Tadoussac. | | 47° 53′ | 290° 18′ | 1833. | Bayfield. | 17° 20′ | +0° 16′ | 17° 36′ | Brandy Pots. | | 47° 51′ | 290° 26′ | 1831. | Bayfield. | 17° 36′ | +0° 19′ | 17° 55′ | River du Loup. | | 46° 57′ | 290° 33′ | Sept. 1844. | Boundary Survey. | 16° 29′ | −0° 16′ | 16° 13′ | Astron. Station, Big Black River. | | 48° 12′ | 290° 51′ | 1829. | U.S. Coast Survey. | 17° 34′ | +0° 24′ | 17° 58′ | Razade Islands. | | 48° 37′ | 290° 53′ | 1831. | Bayfield. | 17° 36′ | +0° 19′ | 17° 55′ | Port Neuf. | | 47° 14′ | 290° 59′ | Sept. & Oct. 1843. | Boundary Survey. | 17° 24′ | −0° 18′ | 17° 06′ | Astron. Station, River St. Francis. | | 47° 11′ | 291° 04′ | Oct. 1842. | Boundary Survey. | 17° 03′ | −0° 13′ | 16° 50′ | Astron. Station, near the mouth of the River St. Francis. | | 48° 25′ | 291° 11′ | 1830. | Bayfield. | 17° 29′ | +0° 24′ | 17° 53′ | Bic Island. | | 47° 16′ | 291° 16′ | Oct. 1842. | Boundary Survey. | 17° 58′ | −0° 13′ | 17° 45′ | Savage Island. | | 48° 55′ | 291° 22′ | 1831. | Bayfield. | 18° 48′ | +0° 22′ | 19° 10′ | Bersimis Point. | | 47° 17′ | 291° 37′ | Oct. 1842. | Boundary Survey. | 17° 58′ | −0° 13′ | 17° 45′ | Bourgeois's House. | | 46° 31′ | 291° 38′ | Aug. 1841. | Boundary Survey. | 16° 43′ | −0° 07′ | 16° 36′ | Mouth of the Massardis River. | | 47° 12′ | 291° 46′ | Aug. 1842. | Boundary Survey. | 17° 53′ | −0° 12′ | 17° 41′ | Lake Cleveland. | | 47° 19′ | 291° 50′ | Aug. 1843. | Boundary Survey. | 18° 06′ | −0° 17′ | 17° 49′ | Mouth of Green River. | | 41° 06′ | 292° 04′ | June 1841. | Barnett. | 10° 08′ | −0° 03′ | 10° 05′ | At sea†. | | 46° 46′ | 292° 10′ | July 1841. | Boundary Survey. | 17° 27′ | −0° 07′ | 17° 20′ | Near Fort Fairfield. | | 49° 18′ | 292° 12′ | 1830. | Bayfield. | 19° 57′ | +0° 26′ | 20° 23′ | St. Nicholas Harbour. | | 46° 59′ | 292° 13′ | Nov. 1841. | Boundary Survey. | 17° 43′ | −0° 08′ | 17° 35′ | Peacock Hill. | | 46° 47′ | 292° 13′ | Oct. 1841. | Boundary Survey. | 17° 28′ | −0° 08′ | 17° 20′ | Aroostook Hill. | | 46° 38′ | 292° 13′ | Oct. 1841. | Boundary Survey. | 17° 15′ | −0° 08′ | 17° 07′ | Blue Hill. | | 46° 07′ | 292° 13′ | Dec. 1840. | Boundary Survey. | 16° 09′ | −0° 04′ | 16° 05′ | Parks Hill. | | 45° 57′ | 292° 13′ | Oct. 1840. | Boundary Survey. | 16° 00′ | −0° 03′ | 15° 57′ | Astron. Station of the Boundary Commission. | | 49° 04′ | 292° 17′ | 1842. | Lefroy. | 21° 37′ | −0° 08′ | 21° 29′ | At sea†. | | 49° 19′ | 292° 37′ | 1830. | Bayfield. | 20° 13′ | +0° 28′ | 20° 41′ | Port de Monts. | | 49° 38′ | 292° 49′ | 1832. | Bayfield. | 21° 35′ | +0° 24′ | 21° 59′ | Egg Island. | | 49° 06′ | 293° 14′ | 1830. | Bayfield. | 21° 27′ | +0° 28′ | 21° 55′ | Cape Chatte. | | 41° 04′ | 293° 19′ | June 1841. | Barnett. | 11° 55′ | −0° 03′ | 11° 52′ | At sea†. | | 49° 36′ | 293° 21′ | 1842. | Lefroy. | 22° 30′ | −0° 08′ | 22° 22′ | At sea†. | *This observation was made at the Astronomical Station on the due north line, 4578 feet north of the Monument marking the source of the River St. Croix. On a Cedar Post 8 inches square erected in 1817 by the Boundary Commissioners under the Treaty of Ghent, at the source of the River St. Croix, is the following inscription:—Variation 13° 51′2 by one instrument, and 14° by another; signed by ‘Col. Joseph Bouchette, H.B.M. Surveyor, and John Johnson, U.S. Surveyor, 31st July, 1817.’ The Declination in 1840,” (as given above,) “is derived from the following observations made by Lieut.-Col. Graham and Lieut. T. J. Lee: Oct. 18 and 19, 1840 - By Draper’s compass No. 4 ……………… 16° 04′ - By Stancliffe’s compass No. 2 ……….. 15° 58′ - By Draper Nicole’s compass No. 1…….. 15° 59′ - By Draper Nicole’s compass No. 2…….. 16° 01′ - By Potter’s compass No. 3 …………….. 16° 01′ - By Variation Transit …………………….. 15° 59′ Mean 16° 00′ It appears from the comparisons of the two determinations, one in 1817 and the other in 1840, that the West Declination has increased 2° 04′5 in 23′22 years; or at an average rate of 5′3 a year.”—Lieut.-Col. Graham, MSS. ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|-----------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | Between the latitudes of 50° and 40° (continued). | | Lat. | Long. | Date. | Observer. | Declination. | Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|-----------|--------------|--------|------------------------|----------| | 48° 04' | 293° 38' | 1839. | Bayfield. | 20° 15' +0° 02' | 20° 17' | Dalhousie Island. | | 48° 05' | 293° 52' | 1838. | Bayfield. | 20° 23' +0° 07' | 20° 30' | Carleton Point. | | 49° 15' | 294° 16' | 1828. | Bayfield. | 22° 00' +1° 03' | 23° 03' | Mount Louis River. | | 41° 29' | 294° 22' | June 1841. | Barnett. | 12° 27' -0° 05' | 12° 22' | At sea†. | | 48° 01' | 294° 25' | 1838. | Bayfield. | 21° 21' +0° 08' | 21° 29' | Paspebiac. | | 47° 06' | 294° 55' | 1837. | Bayfield. | 19° 46' +0° 15' | 20° 01' | Vin Island, Miramichi. | | 41° 28' | 294° 57' | June 1841. | Barnett. | 13° 05' -0° 05' | 13° 00' | At sea†. | | 47° 49' | 295° 08' | 1838. | Bayfield. | 21° 30' +0° 09' | 21° 39' | Caraquette Island. | | 46° 43' | 295° 12' | 1839. | Bayfield. | 19° 50' +0° 03' | 19° 53' | Richibucto River. | | 48° 12' | 295° 13' | 1837. | Bayfield. | 22° 00' +0° 15' | 22° 15' | Point Macquereau. | | 47° 45' | 295° 17' | 1838. | Bayfield. | 21° 43' +0° 09' | 21° 52' | Shipfrigan Harbour. | | 48° 01' | 295° 30' | 1838. | Bayfield. | 20° 35' +0° 09' | 20° 44' | Miscow Harbour. | | 48° 50' | 295° 30' | 1846. | Bayfield. | 22° 49' -0° 37' | 22° 12' | Gaspé Basin. | | 41° 28' | 295° 34' | June 1841. | Barnett. | 13° 08' -0° 05' | 13° 03' | At sea†. | | 49° 48' | 295° 36' | 1830. | Bayfield. | 24° 22' +0° 52' | 25° 14' | Cape Henry, Anticosti. | | 46° 15' | 295° 37' | 1839. | Bayfield. | 19° 59' +0° 03' | 20° 02' | Shediac Island. | | 46° 48' | 295° 57' | 1845. | Bayfield. | 21° 10' -0° 32' | 20° 38' | Cascumpique. | | 46° 10' | 296° 10' | 1840. | Bayfield. | 20° 00' -0° 03' | 19° 57' | Cape Tormentine. | | 46° 24' | 296° 12' | 1841. | Bayfield. | 20° 12' -0° 09' | 20° 03' | Bedeque Harbour. | | 46° 15' | 296° 17' | 1840. | Bayfield. | 20° 18' -0° 03' | 20° 15' | Carleton Head. | | 46° 34' | 296° 17' | 1845. | Bayfield. | 21° 00' -0° 33' | 20° 27' | Richmond Bay. | | 45° 53' | 296° 19' | 1840. | Bayfield. | 19° 40' -0° 03' | 19° 37' | Pugwash Harbour. | | 45° 49' | 296° 34' | 1840. | Bayfield. | 19° 50' -0° 03' | 19° 47' | Wallace Harbour. | | 46° 30' | 296° 40' | 1845. | Bayfield. | 21° 41' -0° 33' | 21° 08' | Cape Turner. | | 46° 14' | 296° 52' | 1842. | Bayfield. | 21° 03' -0° 15' | 20° 48' | Charlotte Town. | | 45° 41' | 297° 20' | 1841. | Bayfield. | 20° 19' -0° 09' | 20° 10' | Picton Harbour. | | 46° 11' | 297° 27' | 1843. | Bayfield. | 21° 58' -0° 21' | 21° 37' | George Town. | | 45° 38' | 297° 33' | 1842. | Bayfield. | 20° 15' -0° 15' | 20° 00' | Merigomish Harbour. | | 41° 48' | 297° 38' | June 1841. | Barnett. | 15° 54' -0° 06' | 15° 48' | At sea†. | | 49° 34' | 298° 07' | 1842. | Lefroy. | 27° 23' -0° 17' | 27° 06' | At sea†. | | 47° 14' | 298° 10' | 1833. | Bayfield. | 22° 36' +0° 45' | 23° 21' | Amherst Harbour. | | 49° 08' | 298° 18' | 1830. | Bayfield. | 25° 19' +1° 07' | 26° 26' | East Point (Anticosti). | | 45° 30' | 299° 04' | June 1848. | Kelly. | 21° 05' -0° 59' | 20° 06' | Isle Madame. | | 45° 35' | 299° 05' | Sept. 1848. | Kelly. | 22° 30' -0° 59' | 21° 31' | Isle Madame. | | 46° 17' | 299° 37' | Aug. 1848. | Kelly. | 23° 41' -0° 59' | 22° 42' | St. Ann's Harbour, Cape Breton. | | 48° 05' | 299° 40' | 1842. | Lefroy. | 26° 47' -0° 18' | 26° 29' | At sea†. | | 49° 11' | 299° 47' | 1842. | Lefroy. | 28° 16' -0° 18' | 27° 58' | At sea†. | | 47° 18' | 300° 15' | 1842. | Lefroy. | 25° 17' -0° 18' | 24° 59' | At sea†. | | 47° 53' | 300° 35' | 1835. | Bayfield. | 25° 00' +0° 32' | 25° 32' | Cod Roy Island. | | 41° 34' | 304° 23' | June 1841. | Barnett. | 18° 28' -0° 09' | 18° 19' | At sea†. | | 46° 13' | 304° 53' | 1842. | Lefroy. | 26° 32' -0° 23' | 26° 09' | At sea†. | | 45° 52' | 306° 49' | 1842. | Lefroy. | 28° 04' -0° 23' | 27° 41' | At sea†. | | 41° 50' | 307° 14' | Oct. 1839. | Bérard. | 19° 00' +0° 02' | 19° 02' | At sea. | | 47° 34' | 307° 19' | 1844. | Bayfield. | 29° 36' -0° 43' | 28° 53' | St. John's, Newfoundland. | | 42° 54' | 307° 37' | June 1841. | Barnett. | 22° 22' -0° 12' | 22° 10' | At sea†. | | 45° 12' | 309° 48' | 1842. | Lefroy. | 27° 00' -0° 22' | 26° 38' | At sea†. | | 43° 19' | 313° 35' | June 1841. | Barnett. | 24° 57' -0° 12' | 24° 45' | At sea†. | | 43° 34' | 314° 42' | Aug. 1842. | Lefroy. | 26° 49' -0° 23' | 26° 26' | At sea†. | | 43° 06' | 315° 00' | Aug. 1842. | Lefroy. | 26° 15' -0° 24' | 25° 51' | At sea†. | | 43° 00' | 316° 10' | June 1841. | Barnett. | 25° 43' -0° 14' | 25° 29' | At sea†. | | 43° 30' | 317° 51' | Oct. 1839. | Bérard. | 23° 55' +0° 03' | 23° 58' | At sea†. | | 44° 33' | 318° 47' | Aug. 1842. | Lefroy. | 27° 37' -0° 24' | 27° 13' | At sea†. | | 43° 37' | 319° 18' | Aug. 1842. | Lefroy. | 28° 17' -0° 24' | 27° 53' | At sea†. | | 42° 20' | 320° 18' | Aug. 1842. | Lefroy. | 27° 07' -0° 22' | 26° 45' | At sea†. | | 42° 59' | 321° 28' | Aug. 1842. | Lefroy. | 27° 20' -0° 22' | 26° 58' | At sea†. | | 43° 26' | 322° 00' | June 1841. | Barnett. | 28° 51' -0° 12' | 28° 39' | At sea†. | ### TABLE XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|-----------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | 44°14′ | 323°22′ | Aug. 1842. | Lefroy. | 28°32′ | −0°22′ | 28°10′ | At sea†. | | 40°32′ | 323°26′ | Oct. 1837. | Vaillant. | 24°52′ | +0°20′ | 25°12′ | At sea. | | 46°09′ | 323°37′ | Aug. 1842. | Lefroy. | 30°38′ | −0°25′ | 30°13′ | At sea†. | | 40°30′ | 323°56′ | Oct. 1837. | Vaillant. | 25°35′ | +0°20′ | 25°55′ | At sea. | | 43°34′ | 324°30′ | June 1841. | Barnett. | 28°22′ | −0°12′ | 28°10′ | At sea†. | | 43°50′ | 324°30′ | June 1841. | Barnett. | 27°12′ | −0°12′ | 27°00′ | At sea†. | | 48°11′ | 324°30′ | Aug. 1842. | Lefroy. | 31°23′ | −0°25′ | 30°58′ | At sea†. | | 42°03′ | 325°11′ | Oct. 1837. | Vaillant. | 24°25′ | +0°20′ | 24°45′ | At sea. | | 40°37′ | 325°13′ | Oct. 1837. | Vaillant. | 26°42′ | +0°20′ | 27°02′ | At sea. | | 47°06′ | 325°40′ | Aug. 1842. | Lefroy. | 32°24′ | −0°25′ | 31°59′ | At sea†. | | 40°55′ | 326°08′ | Aug. 1830. | Erman. | 24°48′ | +1°16′ | 26°04′ | At sea. | | 46°41′ | 326°36′ | Aug. 1842. | Lefroy. | 30°47′ | −0°22′ | 30°25′ | At sea†. | | 41°39′ | 327°19′ | Aug. 1830. | Erman. | 25°16′ | +1°12′ | 26°28′ | At sea. | | 43°26′ | 329°27′ | Aug. 1830. | Erman. | 26°35′ | +1°08′ | 27°43′ | At sea. | | 42°39′ | 329°55′ | Oct. 1837. | Vaillant. | 23°26′ | +0°15′ | 23°41′ | At sea. | | 47°21′ | 330°56′ | Aug. 1842. | Lefroy. | 30°49′ | −0°18′ | 30°31′ | At sea†. | | 44°35′ | 330°57′ | Aug. 1830. | Erman. | 27°36′ | +1°10′ | 28°46′ | At sea. | | 41°37′ | 331°37′ | 1839. | Du Petit-Thouars. | 22°07′ | +0°04′ | 22°11′ | At sea. | | 45°41′ | 332°57′ | Aug. 1830. | Erman. | 28°08′ | +1°02′ | 29°10′ | At sea. | | 43°18′ | 333°04′ | Oct. 1837. | Vaillant. | 24°22′ | +0°13′ | 24°35′ | At sea. | | 46°53′ | 334°07′ | June 1841. | Barnett. | 29°40′ | −0°08′ | 29°32′ | At sea†. | | 46°20′ | 335°05′ | Aug. 1830. | Erman. | 28°18′ | +0°57′ | 29°15′ | At sea. | | 47°20′ | 335°09′ | Aug. 1842. | Lefroy. | 31°13′ | −0°16′ | 30°57′ | At sea†. | | 46°49′ | 336°05′ | June 1841. | Barnett. | 30°04′ | −0°08′ | 29°56′ | At sea†. | | 44°03′ | 336°25′ | Oct. 1837. | Vaillant. | 24°20′ | +0°14′ | 24°34′ | At sea. | | 45°45′ | 336°26′ | Oct. 1839. | Bérard. | 25°30′ | +0°02′ | 25°32′ | At sea. | | 47°33′ | 336°56′ | Aug. 1842. | Lefroy. | 31°17′ | −0°16′ | 31°01′ | At sea†. | | 40°35′ | 337°15′ | 1836. | FitzRoy. | 25°00′ | +0°14′ | 25°14′ | At sea. | | 46°43′ | 338°23′ | Oct. 1839. | Bérard. | 27°00′ | +0°01′ | 27°01′ | At sea. | | 46°53′ | 338°25′ | June 1841. | Barnett. | 30°51′ | −0°06′ | 30°45′ | At sea†. | | 41°28′ | 338°29′ | 1836. | FitzRoy. | 25°38′ | +0°14′ | 25°52′ | At sea. | | 47°03′ | 339°07′ | Aug. 1830. | Erman. | 27°51′ | +0°45′ | 28°36′ | At sea. | | 47°37′ | 339°46′ | June 1841. | Barnett. | 30°30′ | −0°06′ | 30°24′ | At sea†. | | 42°06′ | 339°54′ | 1836. | FitzRoy. | 26°00′ | +0°12′ | 26°12′ | At sea. | | 43°14′ | 340°17′ | June 1839. | Du Petit-Thouars. | 22°52′ | +0°02′ | 22°54′ | At sea. | | 48°02′ | 340°55′ | Aug. 1842. | Lefroy. | 30°51′ | −0°12′ | 30°39′ | At sea†. | | 47°55′ | 342°25′ | June 1841. | Barnett. | 28°23′ | −0°05′ | 28°18′ | At sea†. | | 48°11′ | 343°18′ | June 1841. | Barnett. | 29°26′ | −0°05′ | 29°21′ | At sea†. | | 49°16′ | 343°51′ | Sept. 1846. | Moore. | 32°01′ | −0°20′ | 31°41′ | At sea†. | | 44°05′ | 344°05′ | June 1839. | Du Petit-Thouars. | 23°09′ | +0°02′ | 23°11′ | At sea. | | 48°18′ | 344°23′ | Aug. 1842. | Lefroy. | 29°29′ | −0°08′ | 29°21′ | At sea†. | | 47°56′ | 345°03′ | Aug. 1830. | Erman. | 26°19′ | +0°29′ | 26°48′ | At sea. | | 48°48′ | 346°00′ | June 1841. | Barnett. | 28°37′ | −0°05′ | 28°32′ | At sea†. | | 40°15′ | 346°10′ | 1836. | FitzRoy. | 24°45′ | +0°10′ | 24°55′ | At sea. | | 41°00′ | 346°30′ | 1836. | FitzRoy. | 24°49′ | +0°10′ | 24°59′ | At sea. | | 42°31′ | 347°20′ | 1836. | FitzRoy. | 24°18′ | +0°10′ | 24°28′ | At sea. | | 42°37′ | 347°30′ | 1836. | FitzRoy. | 23°34′ | +0°10′ | 23°44′ | At sea. | | 43°20′ | 348°00′ | 1836. | FitzRoy. | 23°50′ | +0°10′ | 24°00′ | At sea. | | 48°42′ | 348°04′ | June 1841. | Barnett. | 27°22′ | −0°05′ | 27°17′ | At sea†. | | 48°27′ | 348°32′ | Aug. 1830. | Erman. | 26°07′ | +0°23′ | 26°30′ | At sea. | | 48°48′ | 349°28′ | Aug. 1842. | Lefroy. | 27°44′ | −0°03′ | 27°41′ | At sea†. | | 49°25′ | 350°15′ | Sept. 1846. | Moore. | 27°46′ | 0°00′ | 27°46′ | At sea†. | | 48°57′ | 350°28′ | Aug. 1830. | Erman. | 25°54′ | +0°10′ | 26°04′ | At sea. | | 46°18′ | 351°54′ | June 1839. | Du Petit-Thouars. | 24°14′ | 0°00′ | 24°14′ | At sea. | | 46°38′ | 351°54′ | Dec. 1842. | Jehenne. | 27°10′ | 0°00′ | 27°10′ | At sea. | | 49°11′ | 352°22′ | Aug. 1842. | Lefroy. | 26°16′ | +0°05′ | 26°21′ | At sea†. | Between the latitudes of 50° and 40° (continued). ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination | Correction for Epoch | Corrected Declination | Remarks. | |------|-------|-------------|--------------------|----------------------|----------------------|-----------------------|------------------------| | | | | | | | | | | **Between the latitudes of 50° and 40° (continued).** | | | | | | | | | 47°20' | 353°14' | Aug. 1830. | Erman. | 25°10'0"0" | | 25°10'0"0" | At sea. | | 47°44' | 354°16' | Aug. 1830. | Erman. | 24°35'0"0" | | 24°35'0"0" | At sea. | | 48°09' | 355°02' | June 1839. | Du Petit-Thouars. | 24°03'0"0" | | 24°03'0"0" | At sea. | | 46°59' | 355°13' | Aug. 1830. | Erman. | 24°02'0"0" | | 24°02'0"0" | At sea. | | 48°23' | 355°31' | Nov. 1837. | Darondean. | 24°58'-0"10" | | 24°48'Brest. | | | 49°58' | 356°27' | Aug. 1842. | Lefroy. | 25°18'0"0" | | 25°18'0"0" | At sea†. | | 40°22' | 1°56' | June 1838. | Bérard. | 20°01'0"0" | | 20°01'0"0" | At sea. | | 48°50' | 2°22' | Feb. 1838. | Darondean. | 21°38'0"0" | | 21°38'Paris Observatory.| | | 40°13' | 2°26' | Aug. 1842. | Bérard. | 19°45'0"0" | | 19°45'At sea. | | | 40°24' | 2°27' | June 1838. | Bérard. | 21°29'0"0" | | 21°29'At sea. | | | 40°48' | 2°30' | Aug. 1842. | Bérard. | 19°00'0"0" | | 19°00'At sea. | | | 41°11' | 2°39' | Aug. 1842. | Bérard. | 19°30'0"0" | | 19°30'At sea. | | | 41°26' | 3°52' | Aug. 1842. | Bérard. | 19°30'0"0" | | 19°30'At sea. | | | 41°32' | 4°18' | Aug. 1842. | Bérard. | 19°00'0"0" | | 19°00'At sea. | | | 42°04' | 4°48' | Aug. 1842. | Bérard. | 18°30'0"0" | | 18°30'At sea. | | | 43°05' | 5°55' | Jan. 1836. | Darondean. | 19°16'0"0" | | 19°16'Toulon. | | | 46°12' | 6°09' | Jan. 1843. | Plantamour. | 18°57'+0"15" | | 19°12'Geneva. | | | **Between the latitudes of 40° and 30°.** | | | | | | | | | 32°41' | 280°07' | May 1841. | Barnett. | -2°24'-0"05" | | -2°29'Charleston. | | | 30°54' | 280°15' | May 1841. | Barnett. | -3°07'-0"05" | | -3°12'At sea†. | | | 31°54' | 280°29' | May 1841. | Barnett. | -2°45'-0"05" | | -2°50'At sea†. | | | 38°56' | 283°25' | June 1845. | U.S. Coast Survey. | +2°14'-0"08" | | +2°06'Annapolis. | | | 33°55' | 283°57' | May 1841. | Barnett. | -1°25'-0"05" | | -1°30'At sea†. | | | 39°22' | 284°30' | June 1846. | U.S. Coast Survey. | +3°18'-0"08" | | +3°10'Bombay Hook. | | | 39°25' | 284°40' | June 1846. | U.S. Coast Survey. | 2°15'-0"08" | | 2°07' | | | 39°58' | 284°50' | May 1846. | U.S. Coast Survey. | 3°51'-0"08" | | 3°43'Girard College. | | | 39°10' | 284°52' | June 1846. | U.S. Coast Survey. | 2°59'-0"08" | | 2°51'Egg Island. | | | 38°47' | 284°54' | May 1841. | Barnett. | 4°42'-0"05" | | 4°37'Cape Henlopen. | | | 39°15' | 284°59' | June 1846. | U.S. Coast Survey. | 3°06'-0"05" | | 3°01'Port Norris. | | | 35°08' | 285°28' | May 1841. | Barnett. | 1°57'-0"05" | | 1°52'At sea†. | | | 38°00' | 285°35' | May 1841. | Barnett. | 3°51'-0"02" | | 3°49'At sea†. | | | 39°31' | 285°41' | Nov. 1846. | U.S. Coast Survey. | 4°24'-0"05" | | 4°19'Tuche Island. | | | 38°45' | 289°09' | May 1841. | Barnett. | 6°44'-0"07" | | 6°37'At sea†. | | | 39°18' | 290°20' | May 1841. | Barnett. | 6°58'-0"07" | | 6°51'At sea†. | | | 39°37' | 290°30' | May 1841. | Barnett. | 7°25'-0"07" | | 7°18'At sea†. | | | 39°52' | 291°20' | May 1841. | Barnett. | 7°42'-0"07" | | 7°35'At sea†. | | | 32°23' | 295°09' | Aug. 1846. | Barnett. | 6°53'-0"39" | | 6°14'Bermuda. | | | 32°23' | 295°16' | May 1837. | Milne. | 6°40'+0"15" | | 6°55'Bermuda. | | | 32°18' | 300°42' | Nov. 1842. | Jehenne. | 8°46'-0"18" | | 8°28'At sea. | | | 33°53' | 318°07' | Aug. 1830. | Erman. | 17°00'+1"26" | | 18°26'At sea. | | | 34°44' | 318°13' | Aug. 1830. | Erman. | 17°03'+1"26" | | 18°29'At sea. | | | 33°39' | 318°32' | Aug. 1830. | Erman. | 17°00'+1"26" | | 18°26'At sea. | | | 31°36' | 318°58' | June 1839. | Du Petit-Thouars. | 16°00'+0"04" | | 16°04'At sea. | | | 32°53' | 318°58' | Aug. 1830. | Erman. | 16°28'+1"26" | | 17°54'At sea. | | | 31°56' | 319°20' | June 1839. | Du Petit-Thouars. | 15°52'+0"04" | | 15°56'At sea. | | | 35°59' | 319°32' | Aug. 1830. | Erman. | 18°02'+1"26" | | 19°28'At sea. | | | 31°48' | 319°36' | Aug. 1830. | Erman. | 15°40'+1"26" | | 17°06'At sea. | | | 30°32' | 319°45' | Aug. 1830. | Erman. | 15°03'+1"26" | | 16°29'At sea. | | | 34°04' | 320°12' | June 1839. | Du Petit-Thouars. | 17°22'+0"04" | | 17°26'At sea. | | | 30°48' | 320°16' | May 1846. | Sullivan. | 17°47'-0"58" | | 16°49'At sea†. | | | 32°10' | 321°05' | May 1846. | Sullivan. | 18°15'-0"58" | | 17°17'At sea†. | | | 37°28' | 321°25' | Aug. 1830. | Erman. | 19°43'+1"26" | | 21°09'At sea. | | | 30°02' | 321°27' | June 1839. | Du Petit-Thouars. | 18°30'+0"04" | | 18°34'At sea. | | | 37°05' | 321°35' | Nov. 1842. | Jehenne. | 21°02'-0"22" | | 20°40'At sea. | | | 33°46' | 322°10' | May 1846. | Sullivan. | 19°15'-0"55" | | 18°20'At sea†. | | | 35°17' | 322°14' | Oct. 1837. | Vaillant. | 18°37'+0"20" | | 18°57'At sea. | | MDCCXLIX. | Lat. | Long. | Date | Observer | Observed Declination | Correction for Epoch | Corrected Declination | Remarks | |------|-------|------------|-------------|----------------------|----------------------|----------------------|-------------| | 33°17' | 32°37' | July 1846, Bérard. | 19°13' -0°57' | 18°16' At sea. | | 36°18' | 32°46' | Oct. 1837, Vaillant. | 17°33' +0°20' | 17°53' At sea. | | 38°43' | 32°02' | Aug. 1830, Erman. | 21°43' +1°20' | 23°03' At sea†. | | 37°48' | 32°07' | June 1839, Du Petit-Thouars. | 19°57' +0°04' | 20°01' At sea. | | 32°11' | 32°13' | July 1846, Bérard. | 18°30' -0°57' | 17°33' At sea. | | 33°54' | 32°14' | Oct. 1837, Vaillant. | 18°02' +0°20' | 18°22' At sea. | | 32°46' | 32°41' | July 1846, Bérard. | 18°29' -0°55' | 17°34' At sea. | | 31°04' | 32°03' | 1836, FitzRoy. | 18°28' +0°28' | 18°56' At sea. | | 39°15' | 32°36' | Aug. 1830, Erman. | 23°06' +1°16' | 24°22' At sea. | | 37°09' | 32°36' | May 1846, Sulivan. | 23°37' -0°52' | 22°45' At sea†. | | 30°01' | 32°39' | Oct. 1837, Vaillant. | 18°38' +0°20' | 18°58' At sea. | | 32°03' | 32°55' | 1836, FitzRoy. | 18°22' +0°28' | 18°50' At sea. | | 34°35' | 32°11' | July 1846, Bérard. | 18°34' -0°52' | 17°40' At sea. | | 37°40' | 32°15' | May 1846, Sulivan. | 23°50' -0°50' | 23°00' At sea†. | | 31°01' | 32°41' | Oct. 1837, Vaillant. | 18°02' +0°19' | 18°21' At sea. | | 39°32' | 32°54' | June 1839, Du Petit-Thouars. | 20°55' +0°04' | 20°59' At sea. | | 38°10' | 32°55' | May 1846, Sulivan. | 23°21' -0°50' | 22°31' At sea†. | | 35°17' | 32°58' | July 1846, Bérard. | 19°49' -0°52' | 18°57' At sea. | | 36°38' | 32°48' | July 1846, Bérard. | 20°59' -0°52' | 20°07' At sea. | | 35°38' | 32°28' | 1836, FitzRoy. | 21°34' +0°26' | 22°00' At sea. | | 39°24' | 32°48' | 1843–1844, Vidal. | 27°30' -0°25' | 27°05' Flores. | | 39°41' | 32°53' | 1842, Vidal. | 27°30' -0°18' | 27°12' Corvo. | | 36°40' | 33°52' | July 1846, Bérard. | 20°42' -0°52' | 19°50' At sea. | | 37°15' | 33°06' | 1836, FitzRoy. | 22°09' +0°26' | 22°35' At sea. | | 39°05' | 33°56' | 1843–1844, Vidal. | 26°46' -0°25' | 26°21' Graciosa. | | 37°49' | 33°00' | 1836, FitzRoy. | 24°00' +0°26' | 24°26' At sea. | | 38°39' | 33°47' | 1836, FitzRoy. | 24°19' +0°26' | 24°45' Terceira. | | 38°45' | 33°52' | July 1836, FitzRoy. | 24°21' +0°26' | 24°47' At sea. | | 37°44' | 33°17' | May 1831, Austin. | 24°31' +0°54' | 25°25' St. Michaels. | | 37°48' | 33°20' | 1836, FitzRoy. | 24°15' +0°22' | 24°37' St. Michaels. | | 37°46' | 33°20' | 1843–1844, Vidal. | 25°45' -0°22' | 25°23' St. Michaels. | | 36°57' | 33°55' | 1843–1844, Vidal. | 25°17' -0°22' | 24°55' Santa Maria. | | 36°19' | 33°41' | Aug. 1846, Bérard. | 20°51' -0°36' | 20°15' At sea. | | 37°05' | 34°15' | Nov. 1842, Jehenne. | 21°02' -0°10' | 20°52' At sea. | | 33°00' | 34°50' | 1832, FitzRoy. | 23°00' +0°34' | 23°34' At sea. | | 37°20' | 34°30' | 1836, FitzRoy. | 23°54' +0°14' | 24°08' At sea. | | 38°41' | 34°00' | 1836, FitzRoy. | 23°35' +0°14' | 23°49' At sea. | | 30°02' | 34°18' | Feb. 1836, Vaillant. | 22°24' +0°22' | 22°46' At sea. | | 30°41' | 34°36' | Sept. 1842, Bérard. | 22°00' -0°11' | 21°49' At sea. | | 31°16' | 34°32' | Sept. 1842, Bérard. | 23°00' -0°11' | 22°49' At sea. | | 33°16' | 34°09' | June 1838, Bérard. | 20°01' +0°06' | 20°07' At sea. | | 32°19' | 34°49' | Sept. 1842, Bérard. | 22°45' -0°11' | 22°34' At sea. | | 33°34' | 34°06' | Feb. 1836, Vaillant. | 24°31' +0°23' | 24°54' At sea. | | 33°00' | 35°05' | Sept. 1842, Bérard. | 22°00' -0°08' | 21°52' At sea. | | 34°10' | 35°20' | Sept. 1842, Bérard. | 22°00' -0°08' | 21°52' At sea. | | 31°57' | 35°51' | June 1838, Bérard. | 20°05' +0°05' | 20°10' At sea. | | 35°59' | 35°14' | Feb. 1836, Vaillant. | 22°20' +0°10' | 22°30' At sea. | | 35°25' | 35°16' | Aug. 1846, Bérard. | 21°05' -0°15' | 20°50' At sea. | | 35°25' | 35°11' | June 1838, Bérard. | 22°13' +0°03' | 22°16' At sea. | | 36°11' | 35°34' | Aug. 1846, Bérard. | 20°26' -0°12' | 20°14' At sea. | | 35°29' | 35°47' | Aug. 1846, Bérard. | 20°35' -0°12' | 20°23' At sea. | | 36°26' | 35°03' | Aug. 1846, Bérard. | 19°15' 0°00' | 19°15' At sea. | | 35°48' | 35°00' | 1842, Bérard. | 18°30' +0°03' | 18°33' At sea. | | 36°20' | 35°52' | Aug. 1846, Bérard. | 18°49' +0°10' | 18°59' At sea. | | 36°46' | 35°53' | June 1838, Bérard. | 19°47' -0°04' | 19°43' At sea. | | 36°28' | 35°19' | Aug. 1846, Bérard. | 19°16' +0°18' | 19°34' At sea. | | 36°10' | 35°40' | Aug. 1846, Bérard. | 19°18' +0°18' | 19°36' At sea. | | 38°58' | 1°00' | Aug. 1846, Bérard. | 19°48' +0°18' | 20°06' At sea. | ### Table XII. (Continued.) | Lat. | Long. | Date | Observer | Observed Declination | Correction for Epoch | Corrected Declination | Remarks | |------|-------|------------|--------------|----------------------|----------------------|-----------------------|--------------------------| | 37° 33' | 1° 15' | Aug. 1842, Bérard. | 17° 37' + 0° 07' | 17° 44' At sea. | | 36° 47' | 3° 05' | Oct. 1842, Aime. | 18° 35' + 0° 08' | 18° 43' Algiers Magnetic Observatory. | | 28° 22' | 279° 35' | May 1841, Barnett. | - 4° 57' - 0° 05' | - 5° 02' At sea†. | | 29° 17' | 280° 24' | May 1841, Barnett. | - 4° 44' - 0° 05' | - 4° 49' At sea†. | | 25° 05' | 282° 39' | May 1838, Milne. | - 3° 07' + 0° 03' | - 3° 04' Nassau. | | 20° 00' | 283° 57' | July 1837, Milne. | - 3° 39' + 0° 04' | - 3° 55' St. Jago, Cuba. | | 21° 33' | 284° 15' | Nov. 1842, Jehenne. | - 4° 02' + 0° 03' | - 3° 59' San Domingo. | | 27° 55' | 285° 24' | Nov. 1842, Jehenne. | - 2° 07' - 0° 09' | - 2° 16' At sea. | | 20° 22' | 285° 26' | 1831, Austin. | - 3° 17' + 0° 12' | - 3° 05' Barracoon, Cuba. | | 22° 07' | 285° 36' | 1831, Austin. | - 4° 27' + 0° 12' | - 4° 15' Crooked Island. | | 22° 47' | 285° 39' | July 1837, Milne. | - 2° 34' + 0° 05' | - 2° 29' Crooked Island. | | 20° 14' | 285° 48' | 1831, Austin. | - 2° 27' + 0° 12' | - 2° 15' Cape Maize. | | 21° 26' | 288° 53' | Nov. 1845, Barnett. | - 1° 48' - 0° 12' | - 2° 00' Turks Island, Bahamas. | | 28° 15' | 315° 50' | June 1839, Du Petit-Thouars. | 13° 32' + 0° 04' | 13° 36' At sea. | | 29° 11' | 316° 36' | June 1839, Du Petit-Thouars. | 14° 16' + 0° 02' | 14° 18' At sea. | | 27° 51' | 316° 53' | June 1839, Du Petit-Thouars. | 13° 25' + 0° 02' | 13° 27' At sea. | | 26° 57' | 318° 08' | June 1839, Du Petit-Thouars. | 12° 37' + 0° 02' | 12° 39' At sea. | | 25° 13' | 319° 09' | June 1839, Du Petit-Thouars. | 12° 30' + 0° 02' | 12° 32' At sea. | | 26° 32' | 319° 46' | May 1846, Sullivan. | 13° 17' - 0° 42' | 13° 35' At sea†. | | 29° 27' | 319° 50' | May 1846, Sullivan. | 14° 24' - 0° 42' | 15° 42' At sea†. | | 24° 00' | 320° 08' | June 1839, Du Petit-Thouars. | 11° 30' + 0° 03' | 11° 33' At sea. | | 21° 34' | 320° 18' | May 1846, Sullivan. | 12° 29' - 0° 42' | 11° 47' At sea†. | | 20° 19' | 320° 45' | May 1846, Sullivan. | 11° 23' - 0° 42' | 10° 41' At sea†. | | 22° 34' | 320° 56' | June 1839, Du Petit-Thouars. | 11° 20' + 0° 03' | 11° 23' At sea. | | 28° 12' | 321° 08' | Aug. 1830, Erman. | 14° 33' + 1° 16' | 15° 49' At sea. | | 26° 23' | 321° 57' | Aug. 1830, Erman. | 13° 07' + 1° 03' | 14° 10' At sea. | | 23° 41' | 322° 14' | 1830, Erman. | 11° 50' + 0° 50' | 12° 40' At sea. | | 29° 15' | 323° 40' | 1836, FitzRoy. | 17° 10' + 0° 27' | 17° 37' At sea. | | 22° 48' | 323° 55' | July 1838, Bérard. | 9° 40' + 0° 08' | 9° 48' At sea. | | 28° 07' | 324° 00' | 1836, FitzRoy. | 17° 06' + 0° 21' | 17° 27' At sea. | | 29° 52' | 324° 34' | July 1846, Bérard. | 17° 55' - 0° 39' | 17° 16' At sea. | | 21° 42' | 324° 35' | 1830, Erman. | 11° 58' + 0° 47' | 12° 45' At sea. | | 28° 13' | 324° 41' | July 1846, Bérard. | 17° 30' - 0° 39' | 16° 51' At sea. | | 27° 17' | 325° 13' | July 1846, Bérard. | 17° 57' - 0° 39' | 17° 18' At sea. | | 29° 17' | 325° 32' | Oct. 1837, Vaillant. | 17° 26' + 0° 18' | 17° 44' At sea. | | 25° 00' | 325° 41' | 1836, FitzRoy. | 16° 05' + 0° 21' | 16° 26' At sea. | | 26° 52' | 325° 52' | July 1846, Bérard. | 18° 30' - 0° 39' | 17° 51' At sea. | | 23° 41' | 326° 11' | 1836, FitzRoy. | 15° 20' + 0° 21' | 15° 41' At sea. | | 25° 44' | 326° 34' | July 1846, Bérard. | 17° 26' - 0° 39' | 16° 47' At sea. | | 25° 57' | 327° 12' | Oct. 1837, Vaillant. | 16° 37' + 0° 15' | 16° 52' At sea. | | 23° 20' | 327° 23' | July 1846, Bérard. | 15° 19' - 0° 33' | 14° 46' At sea. | | 23° 02' | 327° 30' | July 1838, Bérard. | 10° 30' + 0° 08' | 10° 38' At sea. | | 21° 27' | 328° 42' | July 1846, Bérard. | 16° 41' + 0° 33' | 16° 08' At sea. | | 22° 30' | 329° 04' | Oct. 1837, Vaillant. | 14° 54' + 0° 12' | 15° 06' At sea. | | 20° 32' | 330° 00' | Oct. 1837, Vaillant. | 14° 22' + 0° 12' | 14° 34' At sea. | | 25° 05' | 330° 33' | July 1838, Bérard. | 16° 44' + 0° 15' | 16° 59' At sea. | | 26° 12' | 333° 21' | July 1838, Bérard. | 17° 19' + 0° 15' | 17° 34' At sea. | | 20° 24' | 337° 11' | Sept. 1842, Bérard. | 19° 30' - 0° 15' | 19° 15' At sea. | | 21° 24' | 338° 04' | Dec. 1846, Stanley. | 18° 14' - 0° 38' | 17° 36' At sea†. | | 22° 24' | 338° 29' | Sept. 1842, Bérard. | 20° 00' - 0° 15' | 19° 45' At sea. | | 20° 18' | 338° 32' | 1832, FitzRoy. | 18° 20' + 0° 45' | 19° 05' At sea. | | 20° 42' | 338° 39' | 1832, FitzRoy. | 18° 24' + 0° 45' | 19° 09' At sea. | | 23° 22' | 339° 08' | Dec. 1846, Stanley. | 19° 41' - 0° 41' | 19° 00' At sea†. | | 21° 43' | 339° 20' | 1832, FitzRoy. | 18° 30' + 0° 45' | 19° 15' At sea. | | 21° 10' | 339° 35' | Jan. 1837, Du Petit-Thouars. | 18° 42' + 0° 18' | 19° 00' At sea. | | 22° 22' | 340° 04' | Nov. 1839, Ross. | 19° 25' 0° 00' | 19° 25' At sea†. | Between the latitudes of 30° and 20°. ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|--------------------|-----------------------|-----------------------|------------------------|-----------------| | | | | | | | | | #### Between the latitudes of 30° and 20° (continued). | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|--------------------|-----------------------|-----------------------|------------------------|-----------------| | 23° 09' | 34° 13' | Feb. 1836. Vaillant. | 18° 47' + 0° 44' | 19° 31' At sea. | | | | | 22° 01' | 34° 16' | Jan. 1837. Du Petit-Thouars. | 20° 08' + 0° 24' | 20° 32' At sea. | | | | | 21° 50' | 34° 28' | Nov. 1839. Ross. | 19° 30' 0° 00' | 19° 30' At sea†. | | | | | 23° 38' | 34° 43' | Nov. 1839. Ross. | 19° 12' 0° 00' | 19° 12' At sea†. | | | | | 23° 50' | 34° 51' | Sept. 1842. Bérard. | 21° 00' - 0° 15' | 20° 45' At sea. | | | | | 26° 17' | 34° 59' | Jan. 1837. Du Petit-Thouars. | 19° 55' + 0° 16' | 20° 11' At sea. | | | | | 23° 31' | 34° 10' | Nov. 1839. Ross. | 20° 15' 0° 00' | 20° 15' At sea†. | | | | | 24° 31' | 34° 17' | 1832. FitzRoy. | 19° 53' + 0° 41' | 20° 34' At sea. | | | | | 24° 40' | 34° 18' | Feb. 1836. Vaillant. | 21° 02' + 0° 21' | 21° 23' At sea. | | | | | 23° 37' | 34° 31' | Nov. 1839. Ross. | 21° 33' 0° 00' | 21° 33' At sea†. | | | | | 25° 33' | 34° 55' | 1832. FitzRoy. | 19° 59' + 0° 41' | 20° 40' At sea. | | | | | 25° 26' | 34° 58' | Feb. 1836. Vaillant. | 20° 35' + 0° 21' | 20° 56' At sea. | | | | | 24° 58' | 34° 56' | Sept. 1842. Bérard. | 21° 00' - 0° 15' | 20° 45' At sea. | | | | | 26° 59' | 34° 12' | 1832. FitzRoy. | 20° 04' + 0° 41' | 20° 45' At sea. | | | | | 28° 12' | 34° 40' | 1832. FitzRoy. | 20° 20' + 0° 41' | 21° 01' At sea. | | | | | 29° 31' | 34° 40' | 1832. FitzRoy. | 20° 44' + 0° 41' | 21° 25' At sea. | | | | | 28° 26' | 34° 44' | Nov. 1839. Ross. | 20° 31' 0° 00' | 20° 31' At sea†. | | | | | 28° 28' | 34° 45' | 1837. Vidal. | 22° 40' + 0° 10' | 22° 50' Santa Cruz. | | | | | 26° 15' | 34° 06' | Feb. 1836. Vaillant. | 22° 16' + 0° 15' | 22° 31' At sea. | | | | | 27° 22' | 34° 38' | Feb. 1836. Vaillant. | 21° 44' + 0° 15' | 21° 59' At sea. | | | | | 29° 15' | 34° 16' | Sept. 1842. Bérard. | 22° 00' - 0° 10' | 21° 50' At sea. | | | | | 29° 12' | 34° 05' | Feb. 1836. Vaillant. | 22° 02' + 0° 15' | 22° 17' At sea. | | | | #### Between the latitudes of 20° and 10°. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|--------------------|-----------------------|-----------------------|------------------------|-----------------| | 17° 56' | 28° 09' | April 1847. Barnett. | - 3° 40' - 0° 10' | - 3° 50' Jamaica. | | | | | 17° 56' | 28° 09' | Oct. 1837. Milne. | - 4° 18' + 0° 03' | - 4° 15' Jamaica. | | | | | 17° 55' | 28° 44' | 1831. Austin. | - 5° 13' + 0° 12' | - 5° 01' Point Morant. | | | | | 10° 25' | 28° 25' | Sept. 1837. Milne. | - 5° 41' + 0° 04' | - 5° 37' Carthagena. | | | | | 19° 55' | 28° 45' | July 1837. Milne. | - 3° 31' + 0° 05' | - 3° 26' Cumberland Harbour. | | | | | 11° 15' | 28° 45' | Sept. 1837. Milne. | - 5° 29' + 0° 04' | - 5° 25' Santa Martha. | | | | | 19° 39' | 29° 51' | July 1838. Bérard. | - 0° 01' + 0° 03' | - 0° 02' At sea. | | | | | 18° 14' | 29° 61' | 1846. Barnett. | - 0° 56' - 0° 12' | - 1° 08' Anguilla Island. | | | | | 17° 08' | 29° 08' | Nov. 1840. Milne. | - 0° 42' - 0° 01' | - 0° 43' Antigua. | | | | | 17° 08' | 29° 08' | Jan. 1848. Barnett. | - 0° 46' - 0° 16' | - 1° 02' Antigua. | | | | | 13° 05' | 30° 22' | Nov. 1839. Milne. | - 1° 13' 0° 00' | - 1° 13' Barbadoes. | | | | | 13° 05' | 30° 24' | 1846. Schomburgk. | - 1° 27' - 0° 12' | - 1° 39' Barbadoes. | | | | | 18° 18' | 32° 24' | May 1846. Sullivan. | + 11° 24' - 0° 32' | + 10° 52' At sea†. | | | | | 17° 02' | 32° 51' | May 1846. Sullivan. | 9° 38' - 0° 32' | 9° 06' At sea†. | | | | | 19° 19' | 32° 51' | May 1839. Du Petit-Thouars. | 11° 56' + 0° 02' | 11° 58' At sea. | | | | | 15° 21' | 32° 28' | May 1846. Sullivan. | 10° 49' - 0° 35' | 10° 14' At sea†. | | | | | 16° 36' | 32° 27' | May 1839. Du Petit-Thouars. | 11° 13' + 0° 02' | 11° 15' At sea. | | | | | 13° 55' | 32° 01' | May 1839. Du Petit-Thouars. | 11° 34' + 0° 02' | 11° 36' At sea. | | | | | 11° 58' | 32° 30' | May 1839. Du Petit-Thouars. | 11° 42' + 0° 03' | 11° 45' At sea. | | | | | 16° 20' | 32° 52' | July 1830. Erman. | 12° 36' + 0° 54' | 13° 30' At sea. | | | | | 18° 57' | 32° 36' | July 1830. Erman. | 13° 02' + 0° 50' | 13° 52' At sea. | | | | | 19° 22' | 32° 41' | July 1846. Bérard. | 15° 08' - 0° 38' | 14° 30' At sea. | | | | | 15° 13' | 32° 56' | July 1830. Erman. | 13° 08' + 0° 57' | 14° 05' At sea. | | | | | 17° 17' | 33° 40' | July 1846. Bérard. | 17° 16' - 0° 33' | 16° 43' At sea. | | | | | 18° 31' | 33° 57' | Oct. 1837. Vaillant. | 14° 04' + 0° 14' | 14° 18' At sea. | | | | | 14° 01' | 33° 11' | July 1830. Erman. | 12° 40' + 1° 01' | 13° 41' At sea. | | | | | 12° 51' | 33° 31' | July 1830. Erman. | 12° 55' + 1° 01' | 13° 56' At sea. | | | | | 11° 53' | 33° 43' | July 1830. Erman. | 12° 56' + 1° 01' | 13° 57' At sea. | | | | | 16° 39' | 33° 16' | Oct. 1837. Vaillant. | 14° 20' + 0° 15' | 14° 35' At sea. | | | | | 10° 36' | 33° 00' | July 1830. Erman. | 13° 33' + 1° 01' | 14° 34' At sea. | | | | | 12° 17' | 33° 35' | May 1832. FitzRoy. | 13° 43' + 0° 49' | 14° 32' At sea. | | | | | 14° 49' | 33° 41' | Oct. 1837. Vaillant. | 14° 32' + 0° 15' | 14° 47' At sea. | | | | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|------------------------|------------------------|---------------------------| | | | | | | | | | | 13° 36′ | 334° 16′ | July 1846. | Bérard. | 17° 04′ − 0° 40′ | 16° 24′ | At sea. | | 13° 02′ | 334° 21′ | Sept. 1842. | Bérard. | 13° 00′ − 0° 17′ | 12° 47′ | At sea. | | 13° 38′ | 334° 26′ | Sept. 1842. | Bérard. | 13° 50′ − 0° 17′ | 13° 37′ | At sea. | | 11° 13′ | 334° 36′ | Sept. 1842. | Bérard. | 15° 00′ − 0° 17′ | 14° 47′ | At sea. | | 13° 20′ | 334° 40′ | May 1832. | FitzRoy. | 14° 49′ + 0° 49′ | 15° 38′ | At sea. | | 13° 55′ | 334° 40′ | Oct. 1837. | Vaillant. | 15° 06′ + 0° 15′ | 15° 18′ | At sea. | | 16° 35′ | 334° 42′ | Sept. 1842. | Bérard. | 17° 00′ − 0° 17′ | 16° 47′ | At sea. | | 10° 00′ | 334° 44′ | Nov. 1839. | Ross. | 15° 47′ 0° 00′ | 15° 47′ | At sea†. | | 12° 46′ | 335° 25′ | Sept. 1837. | Vaillant. | 15° 23′ + 0° 14′ | 15° 37′ | At sea. | | 12° 12′ | 335° 30′ | Nov. 1839. | Ross. | 16° 26′ 0° 00′ | 16° 26′ | At sea†. | | 15° 29′ | 336° 08′ | 1832. | FitzRoy. | 15° 52′ + 0° 49′ | 16° 41′ | At sea. | | 14° 43′ | 336° 21′ | 1836. | FitzRoy. | 17° 02′ + 0° 21′ | 17° 23′ | At sea. | | 15° 17′ | 336° 25′ | 1832. | FitzRoy. | 15° 22′ + 0° 49′ | 16° 11′ | At sea. | | 10° 13′ | 336° 28′ | Jan. 1837. | Du Petit-Thouars. | 16° 59′ + 0° 18′ | 17° 17′ | At sea. | | 14° 56′ | 336° 28′ | Nov. 1839. | Ross. | 16° 26′ 0° 00′ | 16° 26′ | At sea†. | | 14° 54′ | 336° 30′ | 1831. | FitzRoy. | 16° 30′ + 0° 55′ | 17° 25′ | Port Praya. | | 13° 36′ | 336° 37′ | July 1846. | Bérard. | 17° 04′ − 0° 39′ | 16° 25′ | At sea. | | 15° 49′ | 336° 40′ | Jan. 1847. | Stanley. | 18° 04′ − 0° 42′ | 17° 22′ | At sea†. | | 11° 59′ | 336° 47′ | Sept. 1837. | Vaillant. | 16° 42′ + 0° 14′ | 16° 56′ | At sea. | | 12° 17′ | 336° 48′ | Jan. 1847. | Stanley. | 15° 55′ − 0° 42′ | 15° 13′ | At sea†. | | 17° 50′ | 336° 50′ | 1832. | FitzRoy. | 17° 06′ + 1° 00′ | 18° 06′ | At sea. | | 19° 02′ | 336° 51′ | Jan. 1847. | Stanley. | 20° 35′ − 0° 42′ | 19° 53′ | At sea†. | | 11° 37′ | 337° 00′ | Jan. 1846. | Bérard. | 16° 12′ − 0° 39′ | 15° 33′ | At sea. | | 13° 16′ | 337° 21′ | Jan. 1837. | Du Petit-Thouars. | 17° 32′ + 0° 18′ | 17° 50′ | At sea. | | 12° 48′ | 337° 39′ | July 1846. | Bérard. | 17° 35′ − 0° 42′ | 16° 53′ | At sea. | | 19° 06′ | 337° 43′ | 1832. | FitzRoy. | 17° 39′ + 0° 45′ | 18° 24′ | At sea. | | 18° 42′ | 337° 50′ | Nov. 1839. | Ross. | 17° 58′ 0° 00′ | 17° 58′ | At sea†. | | 19° 31′ | 338° 03′ | 1832. | FitzRoy. | 18° 06′ + 0° 45′ | 18° 51′ | At sea. | | 11° 05′ | 338° 03′ | Sept. 1837. | Vaillant. | 16° 13′ + 0° 15′ | 16° 28′ | At sea. | | 10° 11′ | 338° 56′ | Sept. 1837. | Vaillant. | 16° 27′ + 0° 15′ | 16° 42′ | At sea. | | 11° 05′ | 338° 59′ | Sept. 1837. | Vaillant. | 16° 36′ + 0° 15′ | 16° 51′ | At sea. | | 16° 51′ | 339° 39′ | Feb. 1836. | Vaillant. | 19° 48′ + 0° 26′ | 20° 14′ | At sea. | | 10° 48′ | 339° 41′ | Sept. 1837. | Vaillant. | 16° 06′ + 0° 15′ | 16° 21′ | At sea. | | 13° 41′ | 339° 42′ | Mar. 1836. | Vaillant. | 17° 12′ + 0° 25′ | 17° 37′ | At sea. | | 19° 40′ | 340° 09′ | Feb. 1836. | Vaillant. | 19° 47′ + 0° 25′ | 20° 12′ | At sea. | | 11° 40′ | 344° 15′ | Oct. 1846. | Denham. | 19° 12′ − 0° 40′ | 18° 32′ | Guancho. | | 11° 33′ | 344° 21′ | Sept. 1846. | Denham. | 19° 10′ − 0° 40′ | 18° 30′ | Bulama. | | 11° 52′ | 344° 23′ | Sept. 1846. | Denham. | 20° 13′ − 0° 40′ | 19° 33′ | Bissao. | #### Between the latitudes of 10° and 0°. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|------------------------|------------------------|---------------------------| | 6° 44′ | 298° 45′ | Jan. 1843. | Schomburgk. | −3° 59′ − 0° 06′ | −4° 05′ | Fork of Wenama and Cuguori Rivers. | | 4° 57′ | 298° 59′ | Nov. 1842. | Schomburgk. | −4° 11′ − 0° 06′ | −4° 17′ | Near Mount Roraima. | | 4° 17′ | 299° 42′ | Oct. 1842. | Schomburgk. | −4° 00′ − 0° 05′ | −4° 05′ | Macusi Village, Pakaraima Mts. Junction of Cotinger and Tacuter Rivers. | | 3° 22′ | 299° 48′ | Sept. 1842. | Schomburgk. | −4° 37′ − 0° 05′ | −4° 42′ | River Guainia. | | 8° 25′ | 300° 24′ | April 1841. | Schomburgk. | −2° 50′ − 0° 03′ | −2° 53′ | Pirara, River Rupunuri. | | 3° 39′ | 300° 40′ | Mar. 1842. | Schomburgk. | −4° 00′ − 0° 05′ | −4° 5′ | Penal Settlement. | | 6° 24′ | 301° 18′ | Dec. 1843. | Schomburgk. | −3° 06′ − 0° 08′ | −3° 14′ | Georgetown. | | 6° 49′ | 301° 49′ | Sept. 1841. | Schomburgk. | −2° 44′ − 0° 03′ | −2° 47′ | Rio Trombetas. | | 1° 25′ | 301° 54′ | July 1843. | Schomburgk. | −3° 57′ − 0° 05′ | −4° 02′ | Pianogholo Village. | | 2° 02′ | 303° 32′ | Aug. 1843. | Schomburgk. | −3° 40′ − 0° 06′ | −3° 46′ | Pianogholo Village. | | 9° 39′ | 326° 10′ | May 1846. | Sullivan. | +12° 47′ − 0° 39′ | +12° 08′ | At sea†. | | 2° 04′ | 329° 37′ | July 1830. | Erman. | 10° 12′ + 1° 11′ | 11° 23′ | At sea. | | 4° 01′ | 329° 42′ | July 1830. | Erman. | 11° 08′ + 1° 11′ | 12° 19′ | At sea. | ### Table XII. (Continued.) | Lat. | Long. | Date | Observer | Observed Declination | Correction for Epoch | Corrected Declination | Remarks | |------|-------|------------|--------------|----------------------|----------------------|-----------------------|------------------| | | | | | | | | | | 5° 30' | 329° 48' | May 1846 | Sullivan | 13° 57' | -0° 51' | 13° 06' | At sea† | | 4° 45' | 330° 08' | May 1846 | Sullivan | 12° 53' | -0° 51' | 12° 02' | At sea† | | 2° 05' | 330° 11' | May 1846 | Sullivan | 12° 45' | -0° 51' | 11° 54' | At sea† | | 8° 22' | 330° 16' | May 1839 | Du Petit-Thouars | 13° 04' | +0° 05' | 13° 09' | At sea | | 0° 55' | 330° 36' | Dec. 1832 | FitzRoy | 8° 22' | +0° 56' | 9° 18' | At sea | | 0° 55' | 330° 42' | Dec. 1839 | Ross | 11° 50' | 0° 00' | 11° 50' | St. Paul's Rocks | | 3° 39' | 330° 49' | July 1836 | FitzRoy | 10° 27' | +0° 28' | 10° 55' | At sea | | 2° 32' | 330° 53' | Dec. 1836 | FitzRoy | 10° 23' | +0° 24' | 10° 47' | At sea | | 1° 20' | 330° 55' | Dec. 1832 | FitzRoy | 10° 39' | +0° 56' | 11° 35' | At sea | | 3° 48' | 330° 58' | May 1846 | Sullivan | 13° 04' | -0° 51' | 12° 13' | At sea† | | 2° 49' | 331° 06' | May 1846 | Sullivan | 12° 58' | -0° 51' | 12° 07' | At sea† | | 1° 57' | 331° 38' | Nov. 1839 | Ross | 13° 16' | 0° 00' | 13° 16' | At sea† | | 2° 10' | 332° 10' | Dec. 1832 | FitzRoy | 11° 08' | +0° 56' | 12° 04' | At sea | | 3° 18' | 332° 46' | Nov. 1839 | Ross | 12° 18' | 0° 00' | 12° 18' | At sea† | | 5° 45' | 332° 49' | 1836 | FitzRoy | 11° 26' | +0° 28' | 11° 54' | At sea | | 8° 50' | 332° 58' | 1832 | FitzRoy | 12° 44' | +0° 56' | 13° 40' | At sea | | 5° 26' | 332° 59' | May 1839 | Du Petit-Thouars | 14° 30' | +0° 05' | 14° 35' | At sea | | 8° 58' | 333° 21' | July 1830 | Erman | 12° 21' | +1° 01' | 13° 22' | At sea | | 6° 46' | 333° 52' | Nov. 1839 | Ross | 14° 58' | 0° 00' | 14° 58' | At sea† | | 3° 37' | 333° 52' | Jan. 1837 | Du Petit-Thouars | 13° 19' | +0° 24' | 13° 43' | At sea | | 5° 13' | 334° 35' | Jan. 1837 | Du Petit-Thouars | 15° 14' | +0° 24' | 15° 38' | At sea | | 2° 51' | 334° 38' | May 1839 | Du Petit-Thouars | 14° 10' | +0° 05' | 14° 15' | At sea | | 9° 36' | 335° 04' | Sept. 1842 | Bérard | 15° 00' | -0° 17' | 14° 43' | At sea | | 7° 24' | 335° 32' | Jan. 1837 | Du Petit-Thouars | 16° 02' | +0° 19' | 16° 21' | At sea | | 0° 09' | 335° 35' | May 1839 | Du Petit-Thouars | 14° 53' | +0° 05' | 14° 58' | At sea | | 8° 19' | 336° 05' | Sept. 1842 | Bérard | 15° 30' | -0° 17' | 15° 13' | At sea | | 7° 09' | 336° 51' | Sept. 1842 | Bérard | 15° 30' | -0° 17' | 15° 13' | At sea | | 6° 48' | 336° 52' | Sept. 1842 | Bérard | 14° 00' | -0° 17' | 13° 43' | At sea | | 9° 24' | 337° 22' | Jan. 1847 | Stanley | 16° 06' | -0° 45' | 15° 21' | At sea† | | 6° 40' | 337° 22' | Jan. 1847 | Stanley | 16° 52' | -0° 49' | 16° 03' | At sea† | | 5° 50' | 337° 25' | July 1846 | Bérard | 15° 11' | -0° 45' | 14° 26' | At sea | | 5° 26' | 337° 33' | Jan. 1847 | Stanley | 17° 00' | -0° 49' | 16° 11' | At sea† | | 1° 11' | 337° 35' | Jan. 1847 | Stanley | 16° 14' | -0° 49' | 15° 25' | At sea† | | 4° 38' | 338° 00' | Sept. 1842 | Bérard | 15° 00' | -0° 17' | 14° 43' | At sea | | 4° 34' | 338° 02' | Jan. 1847 | Stanley | 17° 00' | -0° 49' | 16° 11' | At sea† | | 1° 19' | 338° 07' | Oct. 1842 | Bérard | 16° 30' | -0° 19' | 16° 11' | At sea | | 2° 08' | 338° 09' | Jan. 1847 | Stanley | 16° 07' | -0° 56' | 15° 11' | At sea† | | 4° 19' | 338° 14' | Jan. 1847 | Stanley | 16° 31' | -0° 56' | 15° 35' | At sea† | | 4° 56' | 338° 38' | Sept. 1842 | Bérard | 14° 20' | -0° 19' | 14° 01' | At sea | | 8° 45' | 338° 53' | Mar. 1836 | Vaillant | 17° 13' | +0° 23' | 17° 36' | At sea | | 9° 33' | 339° 19' | Sept. 1837 | Vaillant | 16° 46' | +0° 15' | 17° 01' | At sea | | 5° 17' | 339° 20' | Sept. 1842 | Bérard | 15° 00' | +0° 19' | 15° 19' | At sea | | 6° 21' | 339° 21' | Mar. 1836 | Vaillant | 17° 13' | +0° 23' | 17° 36' | At sea | | 8° 48' | 339° 24' | Sept. 1837 | Vaillant | 16° 39' | +0° 15' | 16° 54' | At sea | | 0° 46' | 339° 26' | Jan. 1846 | Bérard | 16° 46' | -0° 49' | 15° 57' | At sea | | 3° 14' | 340° 09' | Sept. 1842 | Bérard | 15° 30' | -0° 18' | 15° 12' | At sea | | 2° 50' | 340° 13' | Mar. 1836 | Vaillant | 17° 47' | +0° 23' | 18° 10' | At sea | | 0° 43' | 340° 14' | Mar. 1836 | Vaillant | 17° 12' | +0° 23' | 17° 35' | At sea | | 2° 50' | 340° 40' | Sept. 1842 | Bérard | 15° 30' | -0° 18' | 15° 12' | At sea | | 8° 21' | 340° 55' | Sept. 1837 | Bérard | 17° 21' | +0° 15' | 17° 36' | At sea | | 6° 18' | 341° 50' | Sept. 1837 | Bérard | 16° 18' | +0° 15' | 16° 33' | At sea | | 4° 30' | 342° 06' | Sept. 1837 | Bérard | 16° 42' | +0° 15' | 16° 57' | At sea | | 0° 34' | 343° 22' | Sept. 1837 | Bérard | 17° 15' | +0° 14' | 17° 29' | At sea | | 9° 27' | 346° 12' | Jan. 1836 | Vidal | 17° 43' | +0° 24' | 18° 07' | Isles de Los. | | 8° 30' | 346° 44' | Feb. 1836 | Vidal | 18° 52' | +0° 24' | 19° 16' | Sierra Leone. | | 8° 30' | 346° 44' | June 1836 | Vidal | 19° 06' | +0° 21' | 19° 27' | Sierra Leone. | Between the latitudes of 10° and 0° (continued). ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|-----------|-----------------------|-----------------------|------------------------|------------------------| | 8° | 30 | Dec. 1836. | Vidal. | 20° 12' + 0° 18' | | 20° 30' | Sierra Leone. | | 8° | 30 | Sept. 1836. | Denham. | 19° 36' - 0° 33' | | 19° 03' | Sierra Leone. | | 7° | 39 | Dec. 1836. | Vidal. | 19° 17' + 0° 18' | | 19° 35' | Moot Island. | | 7° | 00 | Dec. 1837. | Vidal. | 18° 53' + 0° 11' | | 19° 04' | Gallinas. | | 6° | 19 | Dec. 1837. | Vidal. | 19° 29' + 0° 11' | | 19° 40' | Cape Mesurada. | | 6° | 09 | Jan. 1837. | Vidal. | 20° 07' + 0° 16' | | 20° 23' | Mourovia. | | 4° | 22 | Feb. 1836. | Vidal. | 20° 00' + 0° 11' | | 20° 11' | Cape Palmas. | | 4° | 22 | Dec. 1845. | Denham. | 19° 05' - 0° 18' | | 18° 47' | Cape Palmas. | | 4° | 45 | May 1837. | Vidal. | 20° 03' 0° 00' | | 20° 03' | Cape Three Points. | | 4° | 48 | April 1838. | Vidal. | 20° 37' 0° 00' | | 20° 37' | Dix Cove. | | 5° | 06 | April 1838. | Vidal. | 20° 11' 0° 00' | | 20° 11' | Cape-Coast Castle. | | 5° | 10 | April 1838. | Vidal. | 20° 13' 0° 00' | | 20° 13' | Annamaboe. | | 5° | 32 | April 1838. | Vidal. | 20° 18' 0° 00' | | 20° 18' | Accra. | | 5° | 32 | Jan. 1846. | Denham. | 20° 39' 0° 00' | | 20° 39' | Accra. | | 5° | 55 | May 1846. | Denham. | 19° 55' 0° 00' | | 19° 55' | Quitta. | | 6° | 13 | Jan. 1846. | Denham. | 20° 21' 0° 00' | | 20° 21' | Little Popoe. | | 6° | 19 | Jan. 1846. | Denham. | 20° 08' 0° 00' | | 20° 08' | Whydah. | | 6° | 24 | Jan. 1846. | Denham. | 20° 30' 0° 00' | | 20° 30' | Badagry. | | 4° | 32 | May 1846. | Denham. | 19° 50' 0° 00' | | 19° 50' | Middleton River. | | 7° | 07 | 1835. | Allen. | 19° 51' 0° 00' | | 19° 51' | Sterling. | | 3° | 46 | Mar. 1836. | Vidal. | 19° 45' 0° 00' | | 19° 45' | Point William. | | 3° | 35 | Mar. 1836. | Vidal. | 19° 50' 0° 00' | | 19° 50' | Fernando Po. | | 3° | 46 | Jan. 1846. | Denham. | 19° 04' 0° 00' | | 19° 04' | Fernando Po. | | 6° | 27 | 1835. | Allen. | 20° 36' 0° 00' | | 20° 36' | Rabba. | | 0° | 55 | Mar. 1836. | Vidal. | 20° 04' 0° 00' | | 20° 04' | Corisco Bay. | | 3° | 55 | April 1836. | Vidal. | 19° 46' 0° 00' | | 19° 46' | Cameroons River. | ### Between the latitudes of 0° and −10°. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|-----------|-----------------------|-----------------------|------------------------|------------------------| | −1° | 28 | Sept. 1830. | Foster. | −1° 14' + 0° 57' | | −0° 17' | Para. | | −2° | 31 | Aug. 1830. | Foster. | +0° 31' + 0° 57' | | +1° 28' | Maranham. | | −0° | 58 | Aug. 1842. | Jehenne. | 5° 47' − 0° 17' | | 5° 30' | At sea. | | −3° | 18 | Aug. 1842. | Jehenne. | 6° 24' − 0° 17' | | 6° 07' | At sea. | | −3° | 41 | Aug. 1842. | Jehenne. | 6° 47' − 0° 19' | | 6° 28' | At sea. | | −8° | 04 | Aug. 1836. | FitzRoy. | 5° 54' + 0° 34' | | 6° 28' | Pernambuco. | | −8° | 03 | Aug. 1836. | FitzRoy. | 5° 10' + 0° 34' | | 5° 44' | At sea. | | −7° | 28 | Jan. 1837. | Du Petit-Thouars. | 9° 45' + 0° 28' | | 10° 13' | At sea. | | −3° | 51 | Jan. 1837. | Du Petit-Thouars. | 9° 30' + 0° 27' | | 9° 57' | At sea. | | −7° | 16 | Dec. 1839. | Ross. | 8° 57' 0° 00' | | 8° 57' | At sea†. | | −3° | 51 | Feb. 1832. | FitzRoy. | 7° 53' + 1° 21' | | 9° 14' | Fernando de Noronha. | | −2° | 36 | Jan. 1837. | Du Petit-Thouars. | 10° 10' + 0° 27' | | 10° 37' | At sea. | | −3° | 09 | Feb. 1832. | FitzRoy. | 7° 54' + 1° 20' | | 9° 14' | At sea. | | −5° | 04 | Feb. 1832. | FitzRoy. | 7° 45' + 1° 20' | | 9° 05' | At sea. | | −9° | 40 | July 1830. | Erman. | 8° 39' + 1° 35' | | 10° 14' | At sea. | | −3° | 29 | Feb. 1832. | FitzRoy. | 8° 00' + 1° 15' | | 9° 15' | At sea. | | −9° | 47 | Dec. 1839. | Ross. | 8° 39' 0° 00' | | 8° 39' | At sea†. | | −7° | 57 | July 1830. | Erman. | 9° 01' + 1° 38' | | 10° 39' | At sea. | | −3° | 03 | Dec. 1839. | Ross. | 10° 15' 0° 00' | | 10° 15' | At sea†. | | −6° | 21 | July 1830. | Erman. | 8° 53' + 1° 38' | | 10° 31' | At sea. | | −9° | 47 | May 1846. | Sullivan. | 9° 03' − 1° 14' | | 7° 49' | At sea†. | | −8° | 18 | May 1846. | Sullivan. | 9° 27' − 1° 14' | | 8° 13' | At sea†. | | −5° | 02 | May 1846. | Sullivan. | 9° 27' − 0° 27' | | 9° 00' | At sea. | | −6° | 46 | May 1846. | Sullivan. | 9° 46' − 1° 05' | | 8° 41' | At sea†. | | −3° | 18 | May 1846. | Sullivan. | 9° 50' − 1° 00' | | 8° 50' | At sea†. | | −5° | 10 | May 1846. | Sullivan. | 9° 46' − 1° 04' | | 8° 42' | At sea†. | | −3° | 23 | July 1830. | Erman. | 9° 17' + 1° 25' | | 10° 42' | At sea. | ### Table XII. (Continued.) | Lat. | Long. | Date | Observer | Observed Declination | Correction for Epoch | Corrected Declination | Remarks | |------|-------|------------|-------------------|----------------------|----------------------|-----------------------|-----------------------| | | | | | | | | | | Between the latitudes of 0° and −10° (continued). | | Lat. | Long. | Date | Observer | Declination | Epoch | Corrected Declination | Remarks | |------|-------|------------|-------------------|---------------------|----------------------|-----------------------|-----------------------| | 1° | 04 | Jan. 1837 | Du Petit-Thouars. | 12° 20' + 0° 26' | At sea | | At sea. | | 1° | 21 | July 1830 | Erman. | 9° 19' + 1° 21' | At sea | | At sea. | | 2° | 50 | May 1846 | Sullivan. | 10° 18' − 1° 00' | At sea | | At sea. | | 0° | 35 | July 1830 | Erman. | 9° 51' + 1° 21' | At sea | | At sea. | | 0° | 28 | Feb. 1832 | FitzRoy. | 8° 10' + 1° 15' | At sea | | At sea. | | 0° | 01 | Feb. 1832 | FitzRoy. | 8° 58' + 1° 15' | At sea | | At sea. | | 0° | 46 | May 1846 | Sullivan. | 10° 54' − 0° 55' | At sea | | At sea. | | 0° | 07 | Dec. 1839 | Ross. | 10° 35' 0° 00' | At sea | | At sea. | | 0° | 18 | Oct. 1842 | Bérard. | 11° 00' − 0° 27' | At sea | | At sea. | | 0° | 47 | Jan. 1847 | Stanley. | 13° 41' − 1° 17' | At sea | | At sea. | | 0° | 59 | Aug. 1842 | Jehenne. | 13° 04' − 0° 25' | At sea | | At sea. | | 0° | 02 | Oct. 1842 | Bérard. | 13° 00' − 0° 25' | At sea | | At sea. | | 0° | 58 | Jan. 1847 | Stanley. | 14° 34' − 1° 11' | At sea | | At sea. | | 0° | 02 | Sept. 1836 | Vaillant. | 11° 30' + 0° 33' | At sea | | At sea. | | 0° | 34 | Jan. 1847 | Stanley. | 14° 27' − 1° 05' | At sea | | At sea. | | 0° | 10 | Oct. 1842 | Bérard. | 15° 45' − 0° 24' | At sea | | At sea. | | 0° | 40 | Oct. 1842 | Bérard. | 15° 00' − 0° 24' | At sea | | At sea. | | 0° | 15 | Mar. 1836 | Vaillant. | 13° 46' + 0° 35' | At sea | | At sea. | | 0° | 41 | Oct. 1842 | Bérard. | 15° 00' − 0° 24' | At sea | | At sea. | | 0° | 48 | Aug. 1842 | Jehenne. | 14° 29' − 0° 26' | At sea | | At sea. | | 0° | 19 | Jan. 1847 | Stanley. | 15° 05' − 1° 10' | At sea | | At sea. | | 0° | 52 | May 1839 | Du Petit-Thouars. | 14° 48' + 0° 04' | At sea | | At sea. | | 0° | 38 | Mar. 1836 | Vaillant. | 14° 30' + 0° 36' | At sea | | At sea. | | 0° | 18 | May 1839 | Du Petit-Thouars. | 15° 58' + 0° 04' | At sea | | At sea. | | 0° | 15 | Mar. 1836 | Vaillant. | 14° 37' + 0° 33' | At sea | | At sea. | | 0° | 40 | Jan. 1846 | Bérard. | 17° 17' − 0° 52' | At sea | | At sea. | | 0° | 56 | Jan. 1846 | Bérard. | 17° 47' − 0° 52' | At sea | | At sea. | | 0° | 29 | May 1839 | Du Petit-Thouars. | 16° 33' + 0° 05' | At sea | | At sea. | | 0° | 30 | June 1846 | Bérard. | 15° 56' + 0° 35' | At sea | | At sea. | | 0° | 45 | Jan. 1846 | Bérard. | 19° 01' − 0° 54' | At sea | | At sea. | | 0° | 55 | May 1839 | Du Petit-Thouars. | 18° 46' + 0° 05' | At sea | | At sea. | | 0° | 38 | Jan. 1846 | Bérard. | 19° 27' − 0° 54' | At sea | | At sea. | | 0° | 11 | Sept. 1837 | Vaillant. | 17° 47' + 0° 20' | At sea | | At sea. | | 0° | 44 | Sept. 1837 | Vaillant. | 17° 34' + 0° 20' | At sea | | At sea. | | 0° | 12 | Sept. 1837 | Vaillant. | 18° 52' + 0° 22' | At sea | | At sea. | | 0° | 56 | Sept. 1837 | Vaillant. | 17° 53' + 0° 20' | At sea | | At sea. | | 0° | 55 | June 1846 | Bérard. | 19° 16' − 0° 58' | Anchorage, Ascension.| | | | 0° | 54 | May 1839 | Du Petit-Thouars. | 18° 31' + 0° 04' | Anchorage, Ascension.| | | | 0° | 54 | May 1839 | Du Petit-Thouars. | 17° 36' + 0° 31' | Anchorage, Ascension.| | | | 0° | 11 | Sept. 1837 | Vaillant. | 19° 13' + 0° 20' | At sea | | At sea. | | 0° | 17 | May 1839 | Du Petit-Thouars. | 18° 54' + 0° 04' | At sea | | At sea. | | 0° | 49 | Sept. 1837 | Vaillant. | 17° 58' + 0° 20' | At sea | | At sea. | | 0° | 52 | June 1846 | Bérard. | 17° 43' + 0° 31' | At sea | | At sea. | | 0° | 30 | June 1846 | Bérard. | 19° 16' − 0° 58' | At sea | | At sea. | | 0° | 49 | May 1839 | Du Petit-Thouars. | 19° 37' + 0° 04' | At sea | | At sea. | | 0° | 21 | May 1839 | Boteler. | 21° 01' + 0° 31' | Anno Boua. | | | Between the latitudes of −10° and −20°. | Lat. | Long. | Date | Observer | Declination | Epoch | Corrected Declination | Remarks | |------|-------|------------|-------------------|---------------------|----------------------|-----------------------|-----------------------| | −18° | 25 | Dec. 1843 | Pasley. | 3° 10' − 0° 38' | At sea | | At sea. | | −18° | 14 | 1832 | FitzRoy. | 1° 04' + 1° 10' | At sea | | At sea. | | −17° | 13 | 1832 | FitzRoy. | 1° 08' + 1° 10' | At sea | | At sea. | | −16° | 35 | 1832 | FitzRoy. | 1° 52' + 1° 10' | At sea | | At sea. | | −18° | 59 | 1832 | FitzRoy. | 1° 14' + 1° 10' | At sea | | At sea. | | −17° | 58 | 1832 | FitzRoy. | 2° 00' + 1° 13' | Abrolhos Island. | | | | −15° | 01 | 1832 | FitzRoy. | 1° 30' + 1° 10' | At sea | | At sea. | | −13° | 25 | 1832 | FitzRoy. | 2° 08' + 1° 10' | At sea | | At sea. | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | Between the latitudes of $-10^\circ$ and $-20^\circ$ (continued). | | Lat. | Long. | Date. | Observer. | Declination. | Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|--------------|--------|------------------------|----------| | $-18^\circ$ | $321^\circ$ | $24'$ | 1832, FitzRoy. | $2^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $29'$ | At sea. | | $-13^\circ$ | $321^\circ$ | $29'$ | 1832, FitzRoy. | $2^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $19'$ | At sea. | | $-12^\circ$ | $321^\circ$ | $29'$ | Feb. 1832, FitzRoy. | $4^\circ$ | $+1^\circ$ | $14'$ | $5^\circ$ | $32'$ | Bahia. | | $-12^\circ$ | $321^\circ$ | $30'$ | Oct. 1842, Bérard. | $3^\circ$ | $-0^\circ$ | $25'$ | $3^\circ$ | $05'$ | At sea. | | $-13^\circ$ | $321^\circ$ | $30'$ | 1836, FitzRoy. | $2^\circ$ | $+0^\circ$ | $33'$ | $3^\circ$ | $17'$ | At sea. | | $-13^\circ$ | $321^\circ$ | $35'$ | 1832, FitzRoy. | $1^\circ$ | $+1^\circ$ | $10'$ | $2^\circ$ | $44'$ | At sea. | | $-15^\circ$ | $321^\circ$ | $36'$ | 1832, FitzRoy. | $2^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $58'$ | At sea. | | $-16^\circ$ | $321^\circ$ | $36'$ | 1832, FitzRoy. | $1^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $09'$ | At sea. | | $-13^\circ$ | $321^\circ$ | $36'$ | Oct. 1842, Bérard. | $4^\circ$ | $-0^\circ$ | $25'$ | $3^\circ$ | $35'$ | At sea. | | $-17^\circ$ | $321^\circ$ | $37'$ | 1832, FitzRoy. | $2^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $26'$ | At sea. | | $-14^\circ$ | $321^\circ$ | $38'$ | 1832, FitzRoy. | $2^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $30'$ | At sea. | | $-14^\circ$ | $321^\circ$ | $51'$ | Oct. 1842, Bérard. | $4^\circ$ | $-0^\circ$ | $25'$ | $4^\circ$ | $05'$ | At sea. | | $-12^\circ$ | $322^\circ$ | $14'$ | 1836, FitzRoy. | $3^\circ$ | $+0^\circ$ | $32'$ | $3^\circ$ | $46'$ | At sea. | | $-16^\circ$ | $322^\circ$ | $21'$ | Oct. 1842, Bérard. | $3^\circ$ | $-0^\circ$ | $25'$ | $2^\circ$ | $35'$ | At sea. | | $-17^\circ$ | $322^\circ$ | $29'$ | 1832, FitzRoy. | $2^\circ$ | $+1^\circ$ | $10'$ | $3^\circ$ | $30'$ | At sea. | | $-12^\circ$ | $322^\circ$ | $35'$ | Oct. 1842, Bérard. | $7^\circ$ | $-0^\circ$ | $25'$ | $6^\circ$ | $35'$ | At sea. | | $-15^\circ$ | $322^\circ$ | $38'$ | 1832, FitzRoy. | $3^\circ$ | $+1^\circ$ | $10'$ | $4^\circ$ | $13'$ | At sea. | | $-12^\circ$ | $322^\circ$ | $45'$ | 1836, FitzRoy. | $3^\circ$ | $+0^\circ$ | $32'$ | $4^\circ$ | $03'$ | At sea. | | $-16^\circ$ | $323^\circ$ | $03'$ | 1832, FitzRoy. | $3^\circ$ | $+1^\circ$ | $10'$ | $4^\circ$ | $54'$ | At sea. | | $-17^\circ$ | $323^\circ$ | $06'$ | Oct. 1842, Bérard. | $4^\circ$ | $-0^\circ$ | $27'$ | $4^\circ$ | $03'$ | At sea. | | $-12^\circ$ | $323^\circ$ | $13'$ | 1836, FitzRoy. | $4^\circ$ | $+0^\circ$ | $32'$ | $4^\circ$ | $50'$ | At sea. | | $-17^\circ$ | $323^\circ$ | $24'$ | Jan. 1837, Du Petit-Thouars. | $7^\circ$ | $+0^\circ$ | $29'$ | $7^\circ$ | $49'$ | At sea. | | $-17^\circ$ | $323^\circ$ | $43'$ | Jan. 1847, Stanley. | $7^\circ$ | $-1^\circ$ | $06'$ | $5^\circ$ | $54'$ | At sea†. | | $-19^\circ$ | $323^\circ$ | $49'$ | Oct. 1842, Bérard. | $3^\circ$ | $-0^\circ$ | $27'$ | $3^\circ$ | $18'$ | At sea. | | $-18^\circ$ | $324^\circ$ | $04'$ | 1832, FitzRoy. | $3^\circ$ | $+1^\circ$ | $11'$ | $4^\circ$ | $12'$ | At sea. | | $-18^\circ$ | $324^\circ$ | $17'$ | Mar. 1836, Vaillant. | $3^\circ$ | $+0^\circ$ | $35'$ | $4^\circ$ | $16'$ | At sea. | | $-11^\circ$ | $324^\circ$ | $22'$ | Oct. 1842, Bérard. | $8^\circ$ | $-0^\circ$ | $27'$ | $7^\circ$ | $53'$ | At sea. | | $-18^\circ$ | $324^\circ$ | $24'$ | July 1830, Erman. | $4^\circ$ | $+1^\circ$ | $35'$ | $5^\circ$ | $56'$ | At sea. | | $-15^\circ$ | $324^\circ$ | $45'$ | Jan. 1837, Du Petit-Thouars. | $7^\circ$ | $+0^\circ$ | $28'$ | $8^\circ$ | $03'$ | At sea. | | $-19^\circ$ | $324^\circ$ | $50'$ | July 1830, Erman. | $3^\circ$ | $+1^\circ$ | $35'$ | $5^\circ$ | $00'$ | At sea. | | $-19^\circ$ | $324^\circ$ | $59'$ | July 1830, Erman. | $4^\circ$ | $+1^\circ$ | $35'$ | $5^\circ$ | $41'$ | At sea. | | $-11^\circ$ | $325^\circ$ | $25'$ | Oct. 1842, Bérard. | $8^\circ$ | $-0^\circ$ | $26'$ | $8^\circ$ | $14'$ | At sea. | | $-14^\circ$ | $325^\circ$ | $26'$ | Jan. 1847, Stanley. | $8^\circ$ | $-1^\circ$ | $06'$ | $7^\circ$ | $07'$ | At sea†. | | $-17^\circ$ | $325^\circ$ | $36'$ | July 1830, Erman. | $4^\circ$ | $+1^\circ$ | $35'$ | $6^\circ$ | $16'$ | At sea. | | $-16^\circ$ | $325^\circ$ | $42'$ | Mar. 1836, Vaillant. | $4^\circ$ | $+0^\circ$ | $35'$ | $5^\circ$ | $31'$ | At sea. | | $-11^\circ$ | $325^\circ$ | $50'$ | Jan. 1837, Du Petit-Thouars. | $8^\circ$ | $+0^\circ$ | $28'$ | $8^\circ$ | $40'$ | At sea. | | $-16^\circ$ | $326^\circ$ | $02'$ | July 1830, Erman. | $5^\circ$ | $+1^\circ$ | $35'$ | $6^\circ$ | $54'$ | At sea. | | $-14^\circ$ | $326^\circ$ | $49'$ | July 1830, Erman. | $6^\circ$ | $+1^\circ$ | $35'$ | $8^\circ$ | $04'$ | At sea. | | $-15^\circ$ | $326^\circ$ | $52'$ | Mar. 1836, Vaillant. | $6^\circ$ | $+0^\circ$ | $38'$ | $7^\circ$ | $23'$ | At sea. | | $-13^\circ$ | $327^\circ$ | $25'$ | July 1830, Erman. | $7^\circ$ | $+1^\circ$ | $35'$ | $8^\circ$ | $35'$ | At sea. | | $-11^\circ$ | $327^\circ$ | $45'$ | July 1830, Erman. | $7^\circ$ | $+1^\circ$ | $35'$ | $8^\circ$ | $53'$ | At sea. | | $-10^\circ$ | $327^\circ$ | $46'$ | Oct. 1842, Bérard. | $10^\circ$ | $-0^\circ$ | $27'$ | $10^\circ$ | $18'$ | At sea. | | $-12^\circ$ | $327^\circ$ | $58'$ | Jan. 1847, Stanley. | $9^\circ$ | $-1^\circ$ | $10'$ | $7^\circ$ | $51'$ | At sea†. | | $-13^\circ$ | $328^\circ$ | $35'$ | Mar. 1836, Vaillant. | $8^\circ$ | $+0^\circ$ | $38'$ | $8^\circ$ | $44'$ | At sea. | | $-12^\circ$ | $329^\circ$ | $00'$ | Dec. 1839, Ross. | $8^\circ$ | $+0^\circ$ | $00'$ | $8^\circ$ | $25'$ | At sea†. | | $-18^\circ$ | $329^\circ$ | $06'$ | May 1846, Sullivan. | $9^\circ$ | $-1^\circ$ | $08'$ | $8^\circ$ | $03'$ | At sea†. | | $-12^\circ$ | $329^\circ$ | $08'$ | May 1846, Sullivan. | $9^\circ$ | $-1^\circ$ | $08'$ | $8^\circ$ | $05'$ | At sea†. | | $-15^\circ$ | $329^\circ$ | $16'$ | May 1846, Sullivan. | $8^\circ$ | $-1^\circ$ | $08'$ | $7^\circ$ | $23'$ | At sea†. | | $-17^\circ$ | $329^\circ$ | $16'$ | May 1846, Sullivan. | $9^\circ$ | $-1^\circ$ | $08'$ | $7^\circ$ | $53'$ | At sea†. | | $-14^\circ$ | $329^\circ$ | $19'$ | May 1846, Sullivan. | $9^\circ$ | $-1^\circ$ | $08'$ | $7^\circ$ | $52'$ | At sea†. | | $-10^\circ$ | $329^\circ$ | $25'$ | Jan. 1847, Stanley. | $12^\circ$ | $-1^\circ$ | $12'$ | $11^\circ$ | $16'$ | At sea†. | | $-14^\circ$ | $329^\circ$ | $53'$ | Dec. 1839, Ross. | $8^\circ$ | $+0^\circ$ | $00'$ | $8^\circ$ | $33'$ | At sea†. | | $-19^\circ$ | $329^\circ$ | $58'$ | May 1846, Sullivan. | $8^\circ$ | $-1^\circ$ | $08'$ | $7^\circ$ | $50'$ | At sea†. | | $-11^\circ$ | $330^\circ$ | $28'$ | Mar. 1836, Vaillant. | $8^\circ$ | $+0^\circ$ | $40'$ | $8^\circ$ | $40'$ | At sea. | | $-16^\circ$ | $330^\circ$ | $30'$ | Dec. 1839, Ross. | $9^\circ$ | $+0^\circ$ | $00'$ | $9^\circ$ | $09'$ | At sea†. | | $-19^\circ$ | $330^\circ$ | $42'$ | Dec. 1839, Ross. | $9^\circ$ | $+0^\circ$ | $00'$ | $9^\circ$ | $48'$ | At sea†. | | $-12^\circ$ | $331^\circ$ | $05'$ | 1836, FitzRoy. | $8^\circ$ | $+0^\circ$ | $36'$ | $9^\circ$ | $16'$ | At sea. | MDCCCXLIX. Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|-----------------------|------------------------|-------------------| | -10°5' | 331°49' | Mar. 1836. Vaillant. | 9°24' + 0°40' | 10°04' At sea. | | -11°25' | 336°37' | 1836. FitzRoy. | 13°06' + 0°36' | 13°42' At sea. | | -10°06' | 340°27' | Aug. 1842. Jehenne. | 15°23' - 0°28' | 14°55' At sea. | | -10°07' | 341°02' | 1836. FitzRoy. | 15°57' + 0°38' | 16°35' At sea. | | -11°10' | 342°37' | Aug. 1842. Jehenne. | 16°00' - 0°28' | 15°32' At sea. | | -11°59' | 344°10' | June 1846. Bérard. | 21°00' - 1°10' | 19°50' At sea. | | -12°09' | 345°01' | Aug. 1842. Jehenne. | 17°36' - 0°28' | 17°08' At sea. | | -19°20' | 345°44' | Jan. 1840. Ross. | 18°44' 0°00' | 18°44' At sea†. | | -18°43' | 346°00' | Jan. 1840. Ross. | 17°46' 0°00' | 17°46' At sea†. | | -17°37' | 346°23' | Jan. 1840. Ross. | 19°26' 0°00' | 19°26' At sea†. | | -17°08' | 346°43' | Jan. 1840. Ross. | 20°12' 0°00' | 20°12' At sea†. | | -13°07' | 347°00' | Aug. 1842. Jehenne. | 19°41' - 0°26' | 19°15' At sea. | | -16°41' | 347°07' | Jan. 1840. Ross. | 19°32' 0°00' | 19°32' At sea†. | | -16°22' | 347°25' | Jan. 1840. Ross. | 18°18' 0°00' | 18°18' At sea†. | | -10°34' | 347°55' | Sept. 1837. Vaillant. | 18°05' + 0°21' | 18°29' At sea. | | -15°22' | 347°58' | Jan. 1840. Ross. | 20°52' 0°00' | 20°52' At sea†. | | -15°24' | 348°06' | Jan. 1840. Ross. | 20°40' 0°00' | 20°40' At sea†. | | -15°31' | 348°15' | Jan. 1840. Ross. | 20°16' 0°00' | 20°16' At sea†. | | -15°44' | 348°16' | Jan. 1840. Ross. | 19°10' 0°00' | 19°10' At sea†. | | -15°37' | 348°27' | Jan. 1840. Ross. | 19°11' 0°00' | 19°11' At sea†. | | -15°40' | 348°35' | Jan. 1840. Ross. | 18°56' 0°00' | 18°56' At sea†. | | -11°22' | 349°32' | May 1839. Du Petit-Thouars. | 20°14' + 0°06' | 20°20' At sea. | | -12°25' | 349°43' | Sept. 1837. Vaillant. | 18°40' + 0°23' | 19°03' At sea. | | -14°22' | 349°54' | Jan. 1840. Ross. | 19°31' 0°00' | 19°31' At sea†. | | -14°11' | 350°28' | Jan. 1840. Ross. | 21°24' 0°00' | 21°24' At sea†. | | -14°38' | 350°30' | Jan. 1840. Ross. | 21°33' 0°00' | 21°33' At sea†. | | -13°02' | 350°53' | 1836. FitzRoy. | 19°56' + 0°33' | 20°29' At sea. | | -12°40' | 351°06' | May 1839. Du Petit-Thouars. | 21°16' + 0°06' | 21°22' At sea. | | -14°08' | 351°32' | Jan. 1840. Ross. | 21°32' 0°00' | 21°32' At sea†. | | -14°36' | 351°53' | Jan. 1840. Ross. | 21°08' 0°00' | 21°08' At sea†. | | -15°04' | 351°57' | Jan. 1840. Ross. | 21°10' 0°00' | 21°10' At sea†. | | -14°11' | 352°00' | Jan. 1840. Ross. | 21°06' 0°00' | 21°06' At sea†. | | -13°34' | 352°02' | Jan. 1840. Ross. | 22°09' 0°00' | 22°09' At sea†. | | -15°26' | 352°20' | Jan. 1840. Ross. | 21°39' 0°00' | 21°39' At sea†. | | -15°27' | 352°30' | Jan. 1840. Ross. | 21°27' 0°00' | 21°27' At sea†. | | -14°28' | 352°52' | May 1839. Du Petit-Thouars. | 22°18' + 0°05' | 22°23' At sea. | | -18°29' | 352°55' | Feb. 1840. Ross. | 23°11' 0°00' | 23°11' At sea†. | | -17°38' | 353°19' | Feb. 1840. Ross. | 21°37' 0°00' | 21°37' At sea†. | | -15°15' | 353°21' | Jan. 1840. Ross. | 21°29' 0°00' | 21°29' At sea†. | | -17°10' | 353°33' | Feb. 1840. Ross. | 20°54' 0°00' | 20°54' At sea†. | | -15°21' | 354°07' | Jan. 1840. Ross. | 23°27' 0°00' | 23°27' At sea†. | | -15°55' | 354°17' | Feb. 1840. Ross. | 22°53' 0°00' | 22°53' Anchorage at St. Helena. | | -15°55' | 354°17' | June 1846. Bérard. | 23°11' - 0°58' | 23°13' Anchorage at St. Helena. | | -15°55' | 354°17' | May 1839. Du Petit-Thouars. | 22°17' + 0°06' | 22°23' Anchorage at St. Helena. | | -15°57' | 354°19' | Jan. 1841. Magnetical Observ. | 22°51' - 0°09' | 22°42' St. Helena. | | -15°57' | 354°26' | 1836. FitzRoy. | 19°43' + 0°33' | 20°16' At sea. | | -16°27' | 355°24' | Aug. 1842. Jehenne. | 24°03' - 0°25' | 23°38' At sea. | | -19°27' | 355°32' | June 1846. Bérard. | 23°20' - 1°01' | 22°19' At sea. | | -16°13' | 355°34' | June 1846. Bérard. | 23°11' - 1°01' | 22°10' At sea. | | -18°59' | 356°05' | June 1846. Bérard. | 23°20' - 1°01' | 22°19' At sea. | | -17°04' | 356°33' | Sept. 1837. Vaillant. | 22°28' + 0°22' | 22°50' At sea. | | -17°13' | 356°45' | June 1846. Bérard. | 23°21' - 1°01' | 22°20' At sea. | | -18°12' | 356°55' | June 1846. Bérard. | 24°59' - 1°01' | 23°58' At sea. | | -18°52' | 357°15' | Aug. 1842. Jehenne. | 25°15' - 0°25' | 25°20' At sea. | | -29°00' | 300°56' | Jan. 1846. Sullivan. | -10°40' - 0°24' | -11°04' Rio Parana. | Between the latitudes of $-10^\circ$ and $-20^\circ$ (continued). ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|-----------------------|------------------------|---------------------------| | | | | | | | | | | Between the latitudes of $-20^\circ$ and $-30^\circ$. | | $-27$ | $27$ | $301^{\circ}16'$ | Jan. 1846. | Sullivan. | $-9^{\circ}24'$ | $-9^{\circ}48'$ | Corrientes Fort. | | $-27$ | $26$ | $311^{\circ}25'$ | June 1832. | FitzRoy. | $-6^{\circ}30'$ | $-5^{\circ}30'$ | St. Catherine. | | $-29$ | $53$ | $311^{\circ}48'$ | June 1832. | FitzRoy. | $-6^{\circ}27'$ | $-5^{\circ}27'$ | At sea. | | $-27$ | $56$ | $312^{\circ}42'$ | Feb. 1837. | Du Petit-Thouars. | $-4^{\circ}30'$ | $-4^{\circ}07'$ | At sea. | | $-28$ | $41$ | $313^{\circ}39'$ | April 1836. | Vaillant. | $-4^{\circ}12'$ | $-3^{\circ}42'$ | At sea. | | $-27$ | $16$ | $313^{\circ}44'$ | June 1832. | FitzRoy. | $-5^{\circ}10'$ | $-4^{\circ}10'$ | At sea. | | $-27$ | $14$ | $314^{\circ}10'$ | June 1832. | FitzRoy. | $-4^{\circ}34'$ | $-3^{\circ}34'$ | At sea. | | $-26$ | $09$ | $314^{\circ}18'$ | Feb. 1837. | Du Petit-Thouars. | $-2^{\circ}44'$ | $-2^{\circ}21'$ | At sea. | | $-28$ | $15$ | $314^{\circ}53'$ | May 1830. | Erman. | $-4^{\circ}10'$ | $-2^{\circ}54'$ | At sea. | | $-26$ | $18$ | $315^{\circ}28'$ | May 1830. | Erman. | $-3^{\circ}31'$ | $-2^{\circ}15'$ | At sea. | | $-26$ | $49$ | $315^{\circ}55'$ | April 1836. | Vaillant. | $-3^{\circ}06'$ | $-2^{\circ}36'$ | At sea. | | $-26$ | $33$ | $316^{\circ}12'$ | June 1832. | FitzRoy. | $-3^{\circ}39'$ | $-2^{\circ}36'$ | At sea. | | $-24$ | $12$ | $316^{\circ}23'$ | Feb. 1837. | Du Petit-Thouars. | $-2^{\circ}04'$ | $-1^{\circ}41'$ | At sea. | | $-24$ | $12$ | $316^{\circ}36'$ | May 1830. | Erman. | $-2^{\circ}10'$ | $-0^{\circ}50'$ | At sea. | | $-23$ | $30$ | $316^{\circ}40'$ | Feb. 1837. | Du Petit-Thouars. | $-2^{\circ}00'$ | $-1^{\circ}37'$ | At sea. | | $-24$ | $43$ | $316^{\circ}47'$ | May 1830. | Erman. | $-2^{\circ}41'$ | $-1^{\circ}21'$ | At sea. | | $-23$ | $46$ | $316^{\circ}49'$ | May 1832. | Erman. | $-1^{\circ}30'$ | $-0^{\circ}10'$ | At sea. | | $-23$ | $03$ | $316^{\circ}54'$ | June 1832. | FitzRoy. | $-1^{\circ}39'$ | $-0^{\circ}36'$ | At sea. | | $-22$ | $55$ | $316^{\circ}55'$ | June 1832. | FitzRoy. | $-2^{\circ}00'$ | $-0^{\circ}57'$ | Rio de Janeiro. | | $-22$ | $54$ | $316^{\circ}55'$ | June 1830. | Erman. | $-2^{\circ}08'$ | $-0^{\circ}48'$ | Rio de Janeiro. | | $-22$ | $54$ | $316^{\circ}55'$ | April 1836. | Vaillant. | $-0^{\circ}50'$ | $-0^{\circ}19'$ | Rio de Janeiro. | | $-22$ | $54$ | $316^{\circ}55'$ | Feb. 1837. | Du Petit-Thouars. | $-0^{\circ}51'$ | $-0^{\circ}28'$ | Rio de Janeiro. | | $-22$ | $54$ | $316^{\circ}55'$ | July 1845. | Von Helmriecher. | $-0^{\circ}13'$ | $-1^{\circ}00'$ | Rio de Janeiro. | | $-24$ | $06$ | $317^{\circ}07'$ | June 1832. | FitzRoy. | $-1^{\circ}57'$ | $-0^{\circ}54'$ | At sea. | | $-24$ | $00$ | $317^{\circ}09'$ | Feb. 1847. | Stanley. | $-0^{\circ}47'$ | $-1^{\circ}47'$ | At sea†. | | $-23$ | $09$ | $317^{\circ}17'$ | June 1830. | Erman. | $-1^{\circ}39'$ | $-0^{\circ}19'$ | At sea. | | $-24$ | $38$ | $317^{\circ}19'$ | Jan. 1844. | Pasley. | $-1^{\circ}00'$ | $-1^{\circ}34'$ | At sea. | | $-25$ | $23$ | $317^{\circ}37'$ | April 1836. | Vaillant. | $-1^{\circ}09'$ | $-0^{\circ}37'$ | At sea. | | $-23$ | $00$ | $318^{\circ}03'$ | July 1828. | Foster. | $-1^{\circ}07'$ | $+0^{\circ}03'$ | Cape Frio. | | $-24$ | $07$ | $318^{\circ}07'$ | April 1836. | Vaillant. | $-0^{\circ}30'$ | $+0^{\circ}02'$ | At sea. | | $-23$ | $05$ | $318^{\circ}10'$ | April 1836. | Vaillant. | $-2^{\circ}30'$ | $-1^{\circ}58'$ | At sea. | | $-29$ | $17$ | $318^{\circ}13'$ | Dec. 1843. | Pasley. | $0^{\circ}00'$ | $-0^{\circ}34'$ | At sea. | | $-23$ | $30$ | $318^{\circ}13'$ | June 1830. | Erman. | $-1^{\circ}03'$ | $+0^{\circ}17'$ | At sea. | | $-27$ | $11$ | $318^{\circ}38'$ | Jan. 1844. | Pasley. | $0^{\circ}00'$ | $-0^{\circ}34'$ | At sea. | | $-24$ | $56$ | $318^{\circ}38'$ | April 1836. | Vaillant. | $-0^{\circ}23'$ | $+0^{\circ}11'$ | At sea. | | $-22$ | $58$ | $318^{\circ}45'$ | June 1832. | FitzRoy. | $-0^{\circ}24'$ | $+0^{\circ}43'$ | At sea. | | $-22$ | $53$ | $319^{\circ}18'$ | Feb. 1837. | Du Petit-Thouars. | $+2^{\circ}12'$ | $+2^{\circ}38'$ | At sea. | | $-25$ | $59$ | $319^{\circ}19'$ | Feb. 1847. | Stanley. | $1^{\circ}33'$ | $-0^{\circ}29'$ | At sea†. | | $-22$ | $42$ | $319^{\circ}39'$ | June 1832. | FitzRoy. | $0^{\circ}03'$ | $+1^{\circ}13'$ | At sea. | | $-24$ | $48$ | $320^{\circ}23'$ | June 1830. | Erman. | $1^{\circ}03'$ | $+1^{\circ}33'$ | At sea. | | $-20$ | $50$ | $320^{\circ}32'$ | Dec. 1843. | Pasley. | $3^{\circ}00'$ | $-0^{\circ}22'$ | At sea. | | $-22$ | $07$ | $320^{\circ}39'$ | Jan. 1847. | Stanley. | $3^{\circ}01'$ | $-1^{\circ}55'$ | At sea†. | | $-20$ | $12$ | $322^{\circ}06'$ | Jan. 1847. | Stanley. | $5^{\circ}05'$ | $-3^{\circ}59'$ | At sea†. | | $-27$ | $52$ | $322^{\circ}42'$ | Jan. 1847. | Stanley. | $2^{\circ}20'$ | $-1^{\circ}14'$ | At sea†. | | $-24$ | $52$ | $323^{\circ}43'$ | June 1830. | Erman. | $2^{\circ}20'$ | $+1^{\circ}30'$ | At sea. | | $-20$ | $38$ | $324^{\circ}44'$ | June 1830. | Erman. | $3^{\circ}32'$ | $+1^{\circ}30'$ | At sea. | | $-22$ | $28$ | $324^{\circ}46'$ | June 1830. | Erman. | $3^{\circ}33'$ | $+1^{\circ}30'$ | At sea. | | $-22$ | $39$ | $324^{\circ}59'$ | Oct. 1842. | Bérard. | $3^{\circ}30'$ | $-0^{\circ}26'$ | At sea. | | $-24$ | $03$ | $325^{\circ}08'$ | June 1830. | Erman. | $3^{\circ}12'$ | $+1^{\circ}35'$ | At sea. | | $-25$ | $00$ | $325^{\circ}16'$ | June 1830. | Erman. | $2^{\circ}45'$ | $+1^{\circ}35'$ | At sea. | | $-25$ | $09$ | $327^{\circ}42'$ | Oct. 1842. | Bérard. | $5^{\circ}00'$ | $-0^{\circ}26'$ | At sea. | | $-26$ | $58$ | $329^{\circ}17'$ | Oct. 1842. | Bérard. | $4^{\circ}15'$ | $-0^{\circ}27'$ | At sea. | | $-20$ | $30$ | $330^{\circ}37'$ | Dec. 1839. | Ross. | $8^{\circ}01'$ | $0^{\circ}00'$ | At sea†. | | $-21$ | $30$ | $330^{\circ}46'$ | Dec. 1839. | Ross. | $9^{\circ}43'$ | $0^{\circ}00'$ | At sea†. | | $-22$ | $40$ | $330^{\circ}52'$ | Dec. 1839. | Ross. | $9^{\circ}01'$ | $0^{\circ}00'$ | At sea†. | | $-23$ | $19$ | $330^{\circ}56'$ | Dec. 1839. | Ross. | $7^{\circ}45'$ | $0^{\circ}00'$ | At sea†. | 2 g 2 ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | Between the latitudes of $-20^\circ$ and $-30^\circ$ (continued). | | $-27^\circ 42'$ | $331^\circ 10'$ | Nov. 1842. | Bérard. | $6^\circ 15'$ | $-0^\circ 27'$ | $5^\circ 48'$ | At sea. | | $-24^\circ 42'$ | $332^\circ 05'$ | Dec. 1839. | Ross. | $7^\circ 08'$ | $0^\circ 00'$ | $7^\circ 08'$ | At sea†. | | $-26^\circ 58'$ | $333^\circ 24'$ | Dec. 1839. | Ross. | $9^\circ 24'$ | $0^\circ 00'$ | $9^\circ 24'$ | At sea†. | | $-26^\circ 37'$ | $333^\circ 26'$ | Dec. 1839. | Ross. | $8^\circ 02'$ | $0^\circ 00'$ | $8^\circ 02'$ | At sea†. | | $-27^\circ 04'$ | $334^\circ 14'$ | Dec. 1839. | Ross. | $10^\circ 04'$ | $0^\circ 00'$ | $10^\circ 04'$ | At sea†. | | $-27^\circ 40'$ | $335^\circ 06'$ | Dec. 1839. | Ross. | $9^\circ 37'$ | $0^\circ 00'$ | $9^\circ 37'$ | At sea†. | | $-25^\circ 30'$ | $335^\circ 20'$ | Dec. 1839. | Ross. | $10^\circ 35'$ | $0^\circ 00'$ | $10^\circ 35'$ | At sea†. | | $-26^\circ 55'$ | $335^\circ 21'$ | Dec. 1839. | Ross. | $9^\circ 48'$ | $0^\circ 00'$ | $9^\circ 48'$ | At sea†. | | $-25^\circ 45'$ | $335^\circ 43'$ | Dec. 1839. | Ross. | $10^\circ 22'$ | $0^\circ 00'$ | $10^\circ 22'$ | At sea†. | | $-26^\circ 51'$ | $337^\circ 11'$ | Dec. 1839. | Ross. | $11^\circ 10'$ | $0^\circ 00'$ | $11^\circ 10'$ | At sea†. | | $-27^\circ 44'$ | $338^\circ 36'$ | Dec. 1839. | Ross. | $12^\circ 00'$ | $0^\circ 00'$ | $12^\circ 00'$ | At sea†. | | $-28^\circ 15'$ | $340^\circ 08'$ | Jan. 1840. | Ross. | $13^\circ 23'$ | $0^\circ 00'$ | $13^\circ 23'$ | At sea†. | | $-27^\circ 55'$ | $341^\circ 50'$ | Jan. 1840. | Ross. | $13^\circ 13'$ | $0^\circ 00'$ | $13^\circ 13'$ | At sea†. | | $-27^\circ 33'$ | $342^\circ 27'$ | Jan. 1840. | Ross. | $13^\circ 41'$ | $0^\circ 00'$ | $13^\circ 41'$ | At sea†. | | $-25^\circ 48'$ | $342^\circ 55'$ | Jan. 1840. | Ross. | $14^\circ 11'$ | $0^\circ 00'$ | $14^\circ 11'$ | At sea†. | | $-24^\circ 39'$ | $343^\circ 02'$ | Jan. 1840. | Ross. | $14^\circ 26'$ | $0^\circ 00'$ | $14^\circ 26'$ | At sea†. | | $-22^\circ 54'$ | $343^\circ 36'$ | Jan. 1840. | Ross. | $14^\circ 59'$ | $0^\circ 00'$ | $14^\circ 59'$ | At sea†. | | $-20^\circ 20'$ | $345^\circ 07'$ | Jan. 1840. | Ross. | $17^\circ 50'$ | $0^\circ 00'$ | $17^\circ 50'$ | At sea†. | | $-29^\circ 56'$ | $345^\circ 54'$ | June 1846. | Bérard. | $17^\circ 48'$ | $-1^\circ 14'$ | $16^\circ 34'$ | At sea. | | $-27^\circ 00'$ | $346^\circ 33'$ | Jan. 1840. | Ross. | $17^\circ 53'$ | $0^\circ 00'$ | $17^\circ 53'$ | At sea†. | | $-27^\circ 53'$ | $346^\circ 43'$ | Jan. 1840. | Ross. | $18^\circ 30'$ | $0^\circ 00'$ | $18^\circ 30'$ | At sea†. | | $-26^\circ 10'$ | $347^\circ 18'$ | Jan. 1840. | Ross. | $17^\circ 51'$ | $0^\circ 00'$ | $17^\circ 51'$ | At sea†. | | $-25^\circ 23'$ | $347^\circ 49'$ | Jan. 1840. | Ross. | $19^\circ 55'$ | $0^\circ 00'$ | $19^\circ 55'$ | At sea†. | | $-28^\circ 48'$ | $348^\circ 14'$ | Jan. 1840. | Ross. | $18^\circ 19'$ | $0^\circ 00'$ | $18^\circ 19'$ | At sea†. | | $-24^\circ 41'$ | $348^\circ 39'$ | Jan. 1840. | Ross. | $20^\circ 21'$ | $0^\circ 00'$ | $20^\circ 21'$ | At sea†. | | $-28^\circ 05'$ | $349^\circ 16'$ | June 1846. | Bérard. | $19^\circ 56'$ | $-1^\circ 14'$ | $18^\circ 42'$ | At sea. | | $-29^\circ 58'$ | $350^\circ 52'$ | Jan. 1840. | Ross. | $19^\circ 55'$ | $0^\circ 00'$ | $19^\circ 55'$ | At sea†. | | $-23^\circ 32'$ | $351^\circ 04'$ | Feb. 1840. | Ross. | $21^\circ 39'$ | $0^\circ 00'$ | $21^\circ 39'$ | At sea†. | | $-22^\circ 00'$ | $351^\circ 19'$ | Feb. 1840. | Ross. | $22^\circ 17'$ | $0^\circ 00'$ | $22^\circ 17'$ | At sea†. | | $-20^\circ 15'$ | $352^\circ 04'$ | Feb. 1840. | Ross. | $23^\circ 12'$ | $0^\circ 00'$ | $23^\circ 12'$ | At sea†. | | $-20^\circ 51'$ | $2^\circ 38'$ | May 1839. | Du Petit-Thouars. | $25^\circ 27'$ | $+0^\circ 05'$ | $25^\circ 32'$ | At sea. | | $-22^\circ 17'$ | $4^\circ 36'$ | June 1836. | FitzRoy. | $24^\circ 12'$ | $+0^\circ 24'$ | $24^\circ 36'$ | At sea. | | $-22^\circ 56'$ | $5^\circ 06'$ | June 1836. | FitzRoy. | $24^\circ 09'$ | $+0^\circ 24'$ | $24^\circ 33'$ | At sea. | | $-25^\circ 54'$ | $7^\circ 28'$ | April 1839. | Du Petit-Thouars. | $26^\circ 28'$ | $+0^\circ 05'$ | $26^\circ 33'$ | At sea. | | $-26^\circ 35'$ | $7^\circ 33'$ | April 1839. | Du Petit-Thouars. | $26^\circ 28'$ | $+0^\circ 05'$ | $26^\circ 33'$ | At sea. | | $-27^\circ 35'$ | $8^\circ 05'$ | Aug. 1842. | Jehenne. | $28^\circ 00'$ | $-0^\circ 18'$ | $27^\circ 42'$ | At sea. | | $-27^\circ 23'$ | $8^\circ 32'$ | April 1839. | Du Petit-Thouars. | $27^\circ 08'$ | $+0^\circ 05'$ | $27^\circ 13'$ | At sea. | | $-27^\circ 48'$ | $9^\circ 50'$ | Aug. 1837. | Vaillant. | $26^\circ 06'$ | $+0^\circ 18'$ | $26^\circ 24'$ | At sea. | | $-24^\circ 31'$ | $10^\circ 35'$ | Aug. 1837. | Vaillant. | $25^\circ 11'$ | $+0^\circ 18'$ | $25^\circ 29'$ | At sea. | | $-29^\circ 33'$ | $10^\circ 58'$ | April 1839. | Du Petit-Thouars. | $26^\circ 51'$ | $+0^\circ 05'$ | $26^\circ 56'$ | At sea. | | $-29^\circ 05'$ | $12^\circ 01'$ | Aug. 1837. | Vaillant. | $26^\circ 02'$ | $+0^\circ 18'$ | $26^\circ 20'$ | At sea. | Between the latitudes of $-30^\circ$ and $-40^\circ$. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|---------------|-----------------------|-----------------------|------------------------|----------| | $-38^\circ 44'$ | $297^\circ 45'$ | 1833. | FitzRoy. | $-15^\circ 20'$ | $+0^\circ 16'$ | $-15^\circ 04'$ | Argentino Fort. | | $-39^\circ 58'$ | $297^\circ 53'$ | 1833. | FitzRoy. | $-15^\circ 50'$ | $+0^\circ 16'$ | $-15^\circ 34'$ | Indian Head. | | $-39^\circ 52'$ | $297^\circ 54'$ | 1833. | FitzRoy. | $-15^\circ 40'$ | $+0^\circ 16'$ | $-15^\circ 24'$ | Colorado River. | | $-39^\circ 27'$ | $297^\circ 57'$ | 1833. | FitzRoy. | $-15^\circ 30'$ | $+0^\circ 16'$ | $-15^\circ 14'$ | Labyrinth Head. | | $-39^\circ 16'$ | $298^\circ 00'$ | 1833. | FitzRoy. | $-15^\circ 20'$ | $+0^\circ 16'$ | $-15^\circ 04'$ | Ariadne Island. | | $-38^\circ 57'$ | $298^\circ 01'$ | 1833. | FitzRoy. | $-15^\circ 00'$ | $+0^\circ 19'$ | $-14^\circ 41'$ | Point Johnson. | | $-39^\circ 11'$ | $298^\circ 06'$ | 1833. | FitzRoy. | $-15^\circ 10'$ | $+0^\circ 19'$ | $-14^\circ 51'$ | Zuraita Island. | | $-38^\circ 59'$ | $298^\circ 20'$ | 1833. | FitzRoy. | $-14^\circ 50'$ | $+0^\circ 19'$ | $-14^\circ 31'$ | Mount Hermoso. | | $-38^\circ 57'$ | $298^\circ 42'$ | Aug. 1833. | FitzRoy. | $-15^\circ 10'$ | $+0^\circ 20'$ | $-14^\circ 50'$ | At sea. | | $-39^\circ 10'$ | $299^\circ 19'$ | Aug. 1833. | FitzRoy. | $-15^\circ 07'$ | $+0^\circ 26'$ | $-14^\circ 41'$ | At sea. | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | Between the latitudes of $-30^\circ$ and $-40^\circ$ (continued). | | $-31^\circ 41'$ | $299^\circ 34'$ | Jan. 1846 | Sullivan. | $-13^\circ 14'$ | $-0^\circ 24'$ | $-15^\circ 38'$ | Bahada de Santa Fe. | | $-38^\circ 39'$ | $301^\circ 12'$ | 1833 | FitzRoy. | $-14^\circ 00'$ | $+0^\circ 26'$ | $-13^\circ 34'$ | Black Point. | | $-34^\circ 36'$ | $301^\circ 38'$ | 1833 | FitzRoy. | $-11^\circ 40'$ | $+0^\circ 26'$ | $-11^\circ 14'$ | Buenos Ayres. | | $-33^\circ 41'$ | $301^\circ 53'$ | Sept. 1845 | Sullivan. | $-12^\circ 06'$ | $-0^\circ 23'$ | $-12^\circ 29'$ | River Uruguay. | | $-32^\circ 20'$ | $301^\circ 55'$ | Sept. 1845 | Sullivan. | $-11^\circ 14'$ | $-0^\circ 23'$ | $-11^\circ 37'$ | Sandy Island. | | $-34^\circ 28'$ | $302^\circ 11'$ | Aug. 1844 | Sullivan. | $-11^\circ 36'$ | $-0^\circ 18'$ | $-11^\circ 54'$ | Colonia. | | $-38^\circ 17'$ | $302^\circ 21'$ | 1833 | FitzRoy. | $-14^\circ 00'$ | $+0^\circ 28'$ | $-13^\circ 32'$ | Point San Andres. | | $-34^\circ 42'$ | $302^\circ 28'$ | Nov. 1832 | FitzRoy. | $-11^\circ 33'$ | $+0^\circ 32'$ | $-11^\circ 01'$ | At sea. | | $-38^\circ 06'$ | $302^\circ 31'$ | 1833 | FitzRoy. | $-13^\circ 50'$ | $+0^\circ 29'$ | $-13^\circ 21'$ | Cape Corrientes. | | $-35^\circ 43'$ | $302^\circ 41'$ | 1833 | FitzRoy. | $-12^\circ 30'$ | $+0^\circ 29'$ | $-12^\circ 01'$ | Rio Salado. | | $-35^\circ 42'$ | $302^\circ 42'$ | 1833 | FitzRoy. | $-12^\circ 30'$ | $+0^\circ 29'$ | $-12^\circ 01'$ | River Sanborombon. | | $-35^\circ 27'$ | $302^\circ 55'$ | 1833 | FitzRoy. | $-12^\circ 30'$ | $+0^\circ 29'$ | $-12^\circ 01'$ | Point Piedras. | | $-34^\circ 41'$ | $303^\circ 12'$ | Aug. 1832 | FitzRoy. | $-11^\circ 49'$ | $+0^\circ 34'$ | $-11^\circ 15'$ | At sea. | | $-36^\circ 19'$ | $303^\circ 14'$ | 1833 | FitzRoy. | $-13^\circ 00'$ | $+0^\circ 29'$ | $-12^\circ 31'$ | Cape San Antonio. | | $-39^\circ 59'$ | $303^\circ 19'$ | 1833 | FitzRoy. | $-13^\circ 30'$ | $+0^\circ 29'$ | $-13^\circ 01'$ | Medanos Point. | | $-36^\circ 56'$ | $303^\circ 25'$ | Aug. 1832 | FitzRoy. | $-12^\circ 36'$ | $+0^\circ 34'$ | $-12^\circ 02'$ | At sea. | | $-34^\circ 52'$ | $303^\circ 36'$ | Aug. 1833 | FitzRoy. | $-11^\circ 46'$ | $+0^\circ 29'$ | $-12^\circ 15'$ | At sea. | | $-34^\circ 57'$ | $303^\circ 42'$ | Nov. 1832 | FitzRoy. | $-12^\circ 28'$ | $+0^\circ 34'$ | $-11^\circ 54'$ | At sea. | | $-34^\circ 53'$ | $303^\circ 47'$ | 1833 | FitzRoy. | $-12^\circ 40'$ | $+0^\circ 29'$ | $-12^\circ 11'$ | Monte Video. | | $-34^\circ 53'$ | $303^\circ 47'$ | April 1836 | Vaillant. | $-10^\circ 35'$ | $+0^\circ 17'$ | $-10^\circ 18'$ | Monte Video. | | $-34^\circ 54'$ | $303^\circ 48'$ | July 1843 | Sullivan. | $-10^\circ 42'$ | $-0^\circ 16'$ | $-10^\circ 58'$ | Monte Video. | | $-34^\circ 54'$ | $303^\circ 48'$ | Aug. 1844 | Sullivan. | $-10^\circ 53'$ | $-0^\circ 20'$ | $-11^\circ 13'$ | Monte Video. | | $-34^\circ 57'$ | $305^\circ 02'$ | 1833 | FitzRoy. | $-12^\circ 28'$ | $+0^\circ 32'$ | $-11^\circ 56'$ | Gorriti. | | $-35^\circ 14'$ | $305^\circ 14'$ | April 1836 | Vaillant. | $-10^\circ 57'$ | $+0^\circ 20'$ | $-10^\circ 37'$ | At sea. | | $-38^\circ 37'$ | $305^\circ 46'$ | Feb. 1837 | Du Petit-Thouars. | $-10^\circ 34'$ | $+0^\circ 16'$ | $-10^\circ 18'$ | At sea. | | $-35^\circ 52'$ | $306^\circ 16'$ | April 1836 | Vaillant. | $-8^\circ 40'$ | $+0^\circ 20'$ | $-8^\circ 20'$ | At sea. | | $-34^\circ 05'$ | $306^\circ 49'$ | April 1836 | Vaillant. | $-8^\circ 25'$ | $+0^\circ 20'$ | $-8^\circ 05'$ | At sea. | | $-35^\circ 01'$ | $306^\circ 52'$ | April 1836 | Vaillant. | $-10^\circ 14'$ | $+0^\circ 20'$ | $-9^\circ 54'$ | At sea. | | $-34^\circ 57'$ | $307^\circ 31'$ | April 1836 | Vaillant. | $-9^\circ 10'$ | $+0^\circ 20'$ | $-8^\circ 50'$ | At sea. | | $-34^\circ 09'$ | $307^\circ 57'$ | July 1832 | FitzRoy. | $-10^\circ 27'$ | $+0^\circ 45'$ | $-9^\circ 42'$ | At sea. | | $-34^\circ 16'$ | $308^\circ 20'$ | Feb. 1837 | Du Petit-Thouars. | $-7^\circ 28'$ | $+0^\circ 17'$ | $-7^\circ 11'$ | At sea. | | $-39^\circ 49'$ | $308^\circ 53'$ | April 1830 | Erman. | $-11^\circ 44'$ | $+0^\circ 57'$ | $-10^\circ 47'$ | At sea. | | $-33^\circ 16'$ | $309^\circ 27'$ | April 1836 | Vaillant. | $-8^\circ 18'$ | $+0^\circ 22'$ | $-7^\circ 56'$ | At sea. | | $-38^\circ 29'$ | $309^\circ 31'$ | April 1830 | Erman. | $-11^\circ 16'$ | $+0^\circ 57'$ | $-10^\circ 19'$ | At sea. | | $-33^\circ 42'$ | $309^\circ 40'$ | April 1836 | Vaillant. | $-6^\circ 56'$ | $+0^\circ 22'$ | $-6^\circ 34'$ | At sea. | | $-32^\circ 37'$ | $309^\circ 43'$ | Aug. 1837 | Du Petit-Thouars. | $-5^\circ 37'$ | $+0^\circ 17'$ | $-5^\circ 20'$ | At sea. | | $-38^\circ 13'$ | $309^\circ 45'$ | April 1830 | Erman. | $-10^\circ 10'$ | $+1^\circ 06'$ | $-9^\circ 04'$ | At sea. | | $-37^\circ 15'$ | $310^\circ 00'$ | April 1830 | Erman. | $-9^\circ 25'$ | $+1^\circ 06'$ | $-8^\circ 19'$ | At sea. | | $-35^\circ 47'$ | $310^\circ 33'$ | April 1830 | Erman. | $-8^\circ 19'$ | $+1^\circ 06'$ | $-7^\circ 13'$ | At sea. | | $-34^\circ 49'$ | $310^\circ 55'$ | April 1830 | Erman. | $-8^\circ 08'$ | $+1^\circ 06'$ | $-7^\circ 02'$ | At sea. | | $-31^\circ 09'$ | $311^\circ 03'$ | July 1832 | FitzRoy. | $-7^\circ 50'$ | $+0^\circ 53'$ | $-6^\circ 57'$ | At sea. | | $-30^\circ 56'$ | $311^\circ 44'$ | April 1836 | Vaillant. | $-4^\circ 44'$ | $+0^\circ 26'$ | $-4^\circ 18'$ | At sea. | | $-32^\circ 38'$ | $312^\circ 27'$ | 1830 | Erman. | $-7^\circ 17'$ | $+1^\circ 10'$ | $-6^\circ 07'$ | At sea. | | $-30^\circ 51'$ | $313^\circ 22'$ | May 1830 | Erman. | $-5^\circ 13'$ | $+1^\circ 10'$ | $-4^\circ 03'$ | At sea. | | $-30^\circ 23'$ | $316^\circ 15'$ | April 1846 | Sullivan. | $-4^\circ 15'$ | $-1^\circ 00'$ | $-5^\circ 15'$ | At sea†. | | $-30^\circ 12'$ | $318^\circ 18'$ | Dec. 1843 | Pasley. | $0^\circ 00'$ | $-0^\circ 35'$ | $0^\circ 35'$ | At sea. | | $-31^\circ 55'$ | $318^\circ 30'$ | Jan. 1844 | Pasley. | $0^\circ 00'$ | $-0^\circ 35'$ | $0^\circ 35'$ | At sea. | | $-30^\circ 06'$ | $318^\circ 45'$ | April 1846 | Sullivan. | $-2^\circ 10'$ | $-1^\circ 00'$ | $-3^\circ 10'$ | At sea†. | | $-31^\circ 26'$ | $320^\circ 34'$ | Jan. 1844 | Pasley. | $+1^\circ 20'$ | $-0^\circ 36'$ | $+0^\circ 44'$ | At sea. | | $-30^\circ 22'$ | $321^\circ 00'$ | Jan. 1844 | Pasley. | $+1^\circ 00'$ | $-0^\circ 36'$ | $+0^\circ 24'$ | At sea. | | $-31^\circ 20'$ | $322^\circ 06'$ | Jan. 1844 | Pasley. | $+1^\circ 17'$ | $-0^\circ 36'$ | $+0^\circ 43'$ | At sea. | | $-33^\circ 13'$ | $323^\circ 09'$ | Feb. 1847 | Stanley. | $+2^\circ 48'$ | $-1^\circ 12'$ | $+1^\circ 36'$ | At sea†. | | $-30^\circ 50'$ | $323^\circ 14'$ | Feb. 1847 | Stanley. | $+2^\circ 24'$ | $-1^\circ 12'$ | $+1^\circ 12'$ | At sea†. | | $-35^\circ 07'$ | $324^\circ 14'$ | Feb. 1847 | Stanley. | $+2^\circ 49'$ | $-1^\circ 19'$ | $+1^\circ 30'$ | At sea†. | | $-36^\circ 37'$ | $326^\circ 57'$ | Feb. 1847 | Stanley. | $+2^\circ 37'$ | $-1^\circ 24'$ | $+1^\circ 13'$ | At sea†. | | $-37^\circ 24'$ | $328^\circ 42'$ | Feb. 1847 | Stanley. | $+4^\circ 09'$ | $-1^\circ 25'$ | $+2^\circ 44'$ | At sea†. | | Lat. | Long. | Date | Observer | Observed Declination | Correction for Epoch | Corrected Declination | Remarks | |------|-------|------------|-------------------|----------------------|----------------------|----------------------|---------| | -36°50' | 33°2'01" | Feb. 1847 | Stanley | 6°32' | -1°26' | 5°06' | At sea† | | -36°32' | 33°25' | Feb. 1847 | Stanley | 7°51' | -1°26' | 6°25' | At sea† | | -31°01' | 33°58' | Nov. 1842 | Bérard | 11°30' | -0°32' | 10°58' | At sea | | -36°42' | 33°14' | May 1846 | Bérard | 7°54' | -1°14' | 6°40' | At sea | | -36°31' | 33°28' | Feb. 1847 | Stanley | 10°00' | -1°26' | 8°34' | At sea† | | -31°49' | 33°53' | Nov. 1842 | Bérard | 13°45' | -0°34' | 12°41' | At sea | | -38°26' | 33°42' | May 1846 | Bérard | 7°45' | -1°18' | 6°27' | At sea | | -35°18' | 33°23' | May 1846 | Bérard | 11°03' | -1°14' | 9°49' | At sea | | -33°26' | 33°58' | May 1846 | Bérard | 12°44' | -1°14' | 11°30' | At sea | | -35°31' | 34°26' | Feb. 1847 | Stanley | 13°07' | -1°26' | 11°41' | At sea† | | -37°01' | 34°09' | Feb. 1847 | Stanley | 11°13' | -1°26' | 9°47' | At sea† | | -36°52' | 34°31' | Feb. 1847 | Stanley | 11°58' | -1°26' | 10°32' | At sea† | | -32°14' | 34°11' | June 1846 | Bérard | 13°36' | -1°14' | 12°22' | At sea | | -38°02' | 34°00' | Feb. 1847 | Stanley | 13°07' | -1°22' | 12°45' | At sea† | | -30°41' | 34°38' | June 1846 | Bérard | 17°16' | -1°11' | 16°05' | At sea | | -37°57' | 34°19' | Feb. 1847 | Stanley | 14°30' | -1°20' | 13°10' | At sea† | | -34°31' | 35°21' | Nov. 1842 | Bérard | 16°00' | -0°32' | 15°28' | At sea | | -37°27' | 35°40' | Feb. 1847 | Stanley | 18°40' | -1°20' | 17°20' | At sea† | | -30°58' | 35°26' | Feb. 1840 | Ross | 21°48' | -0°02' | 21°46' | At sea† | | -36°05' | 35°10' | Feb. 1847 | Stanley | 20°02' | -1°16' | 18°46' | At sea† | | -31°32' | 35°37' | Feb. 1840 | Ross | 21°54' | -0°02' | 21°52' | At sea† | | -34°45' | 35°39' | Feb. 1847 | Stanley | 21°43' | -1°16' | 20°27' | At sea† | | -35°23' | 35°39' | Feb. 1847 | Stanley | 23°08' | -1°16' | 21°52' | At sea† | | -35°30' | 35°07' | Feb. 1847 | Stanley | 22°41' | -1°16' | 21°25' | At sea† | | -35°42' | 35°09' | Nov. 1842 | Bérard | 21°00' | -0°29' | 20°31' | At sea | | -36°58' | 35°28' | Feb. 1847 | Stanley | 22°16' | -1°12' | 21°04' | At sea† | | -31°01' | 35°26' | Feb. 1840 | Ross | 23°29' | 0°00' | 23°29' | At sea† | | -31°13' | 35°31' | Feb. 1840 | Ross | 23°02' | 0°00' | 23°02' | At sea† | | -30°30' | 35°36' | Feb. 1840 | Ross | 23°08' | 0°00' | 23°08' | At sea† | | -38°23' | 35°37' | Feb. 1847 | Stanley | 22°28' | -1°04' | 21°24' | At sea† | | -31°28' | 35°38' | Feb. 1840 | Ross | 23°41' | 0°00' | 23°41' | At sea† | | -31°19' | 35°46' | Feb. 1840 | Ross | 23°08' | 0°00' | 23°08' | At sea† | | -30°37' | 35°48' | Feb. 1840 | Ross | 23°33' | 0°00' | 23°33' | At sea† | | -38°52' | 1°01' | Feb. 1847 | Stanley | 23°41' | -1°04' | 22°37' | At sea† | | -32°00' | 1°48' | Feb. 1840 | Ross | 24°07' | -0°02' | 24°05' | At sea† | | -32°41' | 4°24' | Feb. 1840 | Ross | 24°49' | -0°02' | 24°47' | At sea† | | -38°19' | 4°37' | Mar. 1847 | Stanley | 24°30' | -1°04' | 23°26' | At sea† | | -33°14' | 6°03' | Mar. 1840 | Ross | 26°48' | -0°02' | 26°46' | At sea† | | -33°29' | 7°48' | Mar. 1840 | Ross | 27°13' | -0°02' | 27°11' | At sea† | | -33°27' | 9°06' | Mar. 1840 | Ross | 28°27' | -0°02' | 28°25' | At sea† | | -37°10' | 9°28' | Mar. 1847 | Stanley | 27°12' | -0°59' | 26°13' | At sea† | | -33°01' | 9°52' | Mar. 1840 | Ross | 28°21' | -0°02' | 28°19' | At sea† | | -38°11' | 10°08' | Nov. 1842 | Bérard | 26°00' | -0°21' | 25°39' | At sea | | -33°14' | 10°37' | Mar. 1840 | Ross | 29°22' | -0°02' | 29°20' | At sea† | | -30°02' | 11°38' | April 1839 | Du Petit-Thouars. | 26°21' | +0°06' | 26°27' | At sea | | -36°40' | 12°05' | Mar. 1847 | Stanley | 27°50' | -0°52' | 26°58' | At sea† | | -31°25' | 13°22' | April 1839 | Du Petit-Thouars. | 27°19' | +0°05' | 27°24' | At sea | | -35°10' | 13°25' | Jan. 1845 | Moore and Clerk. | 25°10' | -0°35' | 25°05' | At sea† | | -33°00' | 13°36' | Mar. 1840 | Ross | 28°44' | -0°02' | 28°42' | At sea† | | -36°20' | 13°48' | Mar. 1847 | Stanley | 28°27' | -0°48' | 27°39' | At sea† | | -35°17' | 14°00' | Jan. 1845 | Moore and Clerk. | 27°15' | -0°20' | 26°45' | At sea† | | -30°40' | 14°09' | Aug. 1837 | Vaillant. | 28°35' | +0°17' | 28°52' | At sea | | -32°53' | 14°21' | Mar. 1840 | Ross | 29°36' | -0°02' | 29°34' | At sea† | | -38°43' | 14°25' | Jan. 1845 | Moore and Clerk. | 25°09' | -0°30' | 24°39' | At sea† | | -39°18' | 14°28' | Jan. 1845 | Moore and Clerk. | 28°20' | -0°30' | 27°50' | At sea† | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|--------------------|-----------------------|-----------------------|------------------------|---------------------------| | | | | | | | | | | Between the latitudes of $-30^\circ$ and $-40^\circ$ (continued). | | $-35^\circ 26'$ | $15^\circ 08'$ | Jan. 1845. | Moore and Clerk. | $28^\circ 39'$ | $-0^\circ 30'$ | $28^\circ 09'$ | At sea†. | | $-32^\circ 57'$ | $15^\circ 27'$ | Aug. 1842. | Jehenne. | $31^\circ 16'$ | $-0^\circ 16'$ | $31^\circ 00'$ | At sea. | | $-32^\circ 23'$ | $15^\circ 52'$ | Mar. 1840. | Ross. | $29^\circ 23'$ | $-0^\circ 02'$ | $29^\circ 21'$ | At sea†. | | $-33^\circ 45'$ | $15^\circ 52'$ | Aug. 1837. | Vaillant. | $28^\circ 43'$ | $+0^\circ 18'$ | $29^\circ 01'$ | At sea. | | $-32^\circ 03'$ | $15^\circ 53'$ | Aug. 1837. | Vaillant. | $27^\circ 16'$ | $+0^\circ 18'$ | $27^\circ 34'$ | At sea. | | $-33^\circ 28'$ | $15^\circ 58'$ | April 1843. | Du Petit-Thouars. | $26^\circ 37'$ | $+0^\circ 04'$ | $26^\circ 41'$ | At sea. | | $-39^\circ 11'$ | $15^\circ 59'$ | Mar. 1843. | Ross. | $28^\circ 22'$ | $-0^\circ 21'$ | $28^\circ 01'$ | At sea†. | | $-39^\circ 52'$ | $16^\circ 04'$ | Mar. 1843. | Crozier. | $26^\circ 38'$ | $-0^\circ 21'$ | $26^\circ 17'$ | At sea†. | | $-35^\circ 59'$ | $16^\circ 22'$ | Mar. 1843. | Crozier. | $27^\circ 50'$ | $-0^\circ 21'$ | $27^\circ 29'$ | At sea†. | | $-38^\circ 26'$ | $16^\circ 39'$ | April 1843. | Ross. | $29^\circ 24'$ | $-0^\circ 21'$ | $29^\circ 03'$ | At sea†. | | $-35^\circ 42'$ | $16^\circ 44'$ | April 1843. | Crozier. | $27^\circ 11'$ | $-0^\circ 21'$ | $26^\circ 50'$ | At sea†. | | $-32^\circ 49'$ | $16^\circ 53'$ | Mar. 1840. | Ross. | $29^\circ 29'$ | $-0^\circ 02'$ | $29^\circ 27'$ | At sea†. | | $-32^\circ 33'$ | $16^\circ 55'$ | Mar. 1840. | Ross. | $29^\circ 25'$ | $-0^\circ 02'$ | $29^\circ 23'$ | At sea†. | | $-33^\circ 21'$ | $17^\circ 07'$ | Mar. 1840. | Ross. | $29^\circ 34'$ | $-0^\circ 02'$ | $29^\circ 32'$ | At sea†. | | $-32^\circ 59'$ | $17^\circ 08'$ | Mar. 1840. | Ross. | $29^\circ 46'$ | $-0^\circ 03'$ | $29^\circ 44'$ | At sea†. | | $-34^\circ 42'$ | $17^\circ 36'$ | Jan. 1845. | Moore and Clerk. | $29^\circ 51'$ | $-0^\circ 32'$ | $29^\circ 19'$ | At sea†. | | $-34^\circ 37'$ | $17^\circ 51'$ | Mar. 1840. | Ross. | $30^\circ 10'$ | $-0^\circ 02'$ | $30^\circ 08'$ | At sea†. | | $-34^\circ 38'$ | $17^\circ 59'$ | April 1839. | Du Petit-Thouars. | $27^\circ 45'$ | $+0^\circ 04'$ | $27^\circ 49'$ | At sea. | | $-34^\circ 18'$ | $18^\circ 03'$ | Mar. 1840. | Ross. | $29^\circ 33'$ | $-0^\circ 02'$ | $29^\circ 31'$ | At sea†. | | $-34^\circ 12'$ | $18^\circ 26'$ | 1840. | Ross. | $29^\circ 04'$ | $-0^\circ 02'$ | $29^\circ 02'$ | At sea†. | | $-34^\circ 11'$ | $18^\circ 27'$ | April 1839. | Du Petit-Thouars. | $29^\circ 09'$ | $+0^\circ 04'$ | $29^\circ 13'$ | False Bay. | | $-33^\circ 56'$ | $18^\circ 29'$ | 1841. | Magnetic Observv. | $29^\circ 07'$ | $0^\circ 00'$ | $29^\circ 07'$ | Cape of Good Hope. | | $-34^\circ 18'$ | $18^\circ 41'$ | Mar. 1830. | Du Petit-Thouars. | $29^\circ 38'$ | $+0^\circ 04'$ | $29^\circ 42'$ | At sea. | Between the latitudes of $-40^\circ$ and $-50^\circ$. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------------|--------------------|-----------------------|-----------------------|------------------------|---------------------------| | $-49^\circ 39'$ | $292^\circ 05'$ | April 1834. | FitzRoy. | $-20^\circ 18'$ | $+0^\circ 14'$ | $-20^\circ 04'$ | At sea. | | $-49^\circ 14'$ | $292^\circ 15'$ | 1833. | RitzRoy. | $-21^\circ 10'$ | $+0^\circ 16'$ | $-20^\circ 54'$ | Wood Mount. | | $-49^\circ 15'$ | $292^\circ 18'$ | 1833. | FitzRoy. | $-21^\circ 00'$ | $+0^\circ 16'$ | $-20^\circ 44'$ | Sholl Point. | | $-49^\circ 11'$ | $292^\circ 23'$ | 1833. | FitzRoy. | $-21^\circ 00'$ | $+0^\circ 16'$ | $-20^\circ 44'$ | Port San Julian. | | $-49^\circ 14'$ | $292^\circ 24'$ | 1833. | FitzRoy. | $-21^\circ 00'$ | $+0^\circ 16'$ | $-20^\circ 44'$ | Desengaño. | | $-45^\circ 57'$ | $292^\circ 26'$ | 1833. | FitzRoy. | $-19^\circ 42'$ | $+0^\circ 16'$ | $-19^\circ 26'$ | Point Marques. | | $-48^\circ 10'$ | $292^\circ 30'$ | Jan. 1834. | FitzRoy. | $-20^\circ 50'$ | $+0^\circ 15'$ | $-20^\circ 35'$ | At sea. | | $-46^\circ 31'$ | $292^\circ 37'$ | 1833. | FitzRoy. | $-19^\circ 40'$ | $+0^\circ 16'$ | $-19^\circ 24'$ | Murphy Head. | | $-45^\circ 46'$ | $292^\circ 38'$ | 1833. | FitzRoy. | $-19^\circ 40'$ | $+0^\circ 16'$ | $-19^\circ 24'$ | Cordova Head. | | $-48^\circ 47'$ | $292^\circ 45'$ | Jan. 1834. | FitzRoy. | $-21^\circ 28'$ | $+0^\circ 15'$ | $-21^\circ 13'$ | At sea. | | $-49^\circ 10'$ | $292^\circ 45'$ | Jan. 1834. | FitzRoy. | $-19^\circ 47'$ | $+0^\circ 15'$ | $-19^\circ 32'$ | At sea. | | $-46^\circ 41'$ | $292^\circ 50'$ | 1833. | FitzRoy. | $-20^\circ 00'$ | $+0^\circ 16'$ | $-19^\circ 44'$ | Bauza Head. | | $-48^\circ 35'$ | $293^\circ 07'$ | 1833. | FitzRoy. | $-21^\circ 00'$ | $+0^\circ 16'$ | $-20^\circ 44'$ | Lookout Point. | | $-45^\circ 10'$ | $293^\circ 28'$ | 1833. | FitzRoy. | $-19^\circ 30'$ | $+0^\circ 16'$ | $-19^\circ 14'$ | Malaspina Cove. | | $-47^\circ 49'$ | $293^\circ 37'$ | 1833. | FitzRoy. | $-20^\circ 20'$ | $+0^\circ 16'$ | $-20^\circ 04'$ | Head of Port Desire. | | $-48^\circ 21'$ | $293^\circ 39'$ | 1833. | FitzRoy. | $-20^\circ 00'$ | $+0^\circ 16'$ | $-19^\circ 44'$ | Watchman Cape. | | $-48^\circ 29'$ | $293^\circ 48'$ | 1833. | FitzRoy. | $-21^\circ 00'$ | $+0^\circ 16'$ | $-20^\circ 44'$ | Bellaco Rock. | | $-48^\circ 23'$ | $293^\circ 50'$ | Jan. 1834. | FitzRoy. | $-19^\circ 43'$ | $+0^\circ 15'$ | $-19^\circ 28'$ | At sea. | | $-47^\circ 45'$ | $294^\circ 00'$ | Jan. 1834. | FitzRoy. | $-20^\circ 30'$ | $+0^\circ 15'$ | $-20^\circ 15'$ | At sea. | | $-48^\circ 45'$ | $294^\circ 00'$ | Jan. 1834. | FitzRoy. | $-18^\circ 22'$ | $+0^\circ 15'$ | $-18^\circ 07'$ | At sea. | | $-47^\circ 45'$ | $294^\circ 08'$ | Jan. 1834. | FitzRoy. | $-19^\circ 57'$ | $+0^\circ 15'$ | $-19^\circ 42'$ | Port Desire. | | $-47^\circ 06'$ | $294^\circ 09'$ | 1833. | FitzRoy. | $-19^\circ 20'$ | $+0^\circ 17'$ | $-19^\circ 03'$ | Cape Three Points. | | $-45^\circ 04'$ | $294^\circ 12'$ | 1833. | FitzRoy. | $-19^\circ 20'$ | $+0^\circ 17'$ | $-19^\circ 03'$ | Melo Port. | | $-47^\circ 57'$ | $294^\circ 14'$ | 1833. | FitzRoy. | $-20^\circ 50'$ | $+0^\circ 17'$ | $-20^\circ 33'$ | Sea-Bear Bay. | | $-47^\circ 12'$ | $294^\circ 17'$ | 1833. | FitzRoy. | $-19^\circ 30'$ | $+0^\circ 17'$ | $-19^\circ 13'$ | Cape Blanco. | | $-45^\circ 04'$ | $294^\circ 19'$ | 1833. | FitzRoy. | $-19^\circ 00'$ | $+0^\circ 17'$ | $-18^\circ 43'$ | South Cape. | | $-44^\circ 56'$ | $294^\circ 28'$ | 1833. | FitzRoy. | $-19^\circ 00'$ | $+0^\circ 17'$ | $-18^\circ 43'$ | Blanco Islet. | | $-44^\circ 31'$ | $294^\circ 38'$ | 1833. | FitzRoy. | $-19^\circ 08'$ | $+0^\circ 17'$ | $-18^\circ 51'$ | Santa Elena. | | $-43^\circ 47'$ | $294^\circ 43'$ | 1833. | FitzRoy. | $-18^\circ 30'$ | $+0^\circ 17'$ | $-18^\circ 13'$ | Lobos Head. | | $-49^\circ 47'$ | $294^\circ 44'$ | April 1834. | FitzRoy. | $-22^\circ 50'$ | $+0^\circ 15'$ | $-22^\circ 35'$ | At sea. | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | -44°12' | 294°45' | 1833. | FitzRoy. | -18°50' + 0°17' | -18°33' | Atlas Point. | | -47°11' | 294°56' | Dec. 1833. | FitzRoy. | -19°50' + 0°16' | -19°34' | Chupat River. | | -43°21' | 294°57' | April 1824. | FitzRoy. | -18°06' + 0°15' | -17°51' | At sea. | | -42°47' | 295°00' | 1833. | FitzRoy. | -17°50' + 0°16' | -17°34' | Western Port. | | -41°40' | 295°06' | 1833. | FitzRoy. | -17°50' + 0°16' | -17°34' | Pozos Point. | | -40°49' | 295°06' | 1833. | FitzRoy. | -17°40' + 0°16' | -17°24' | Port San Antonio. | | -40°08' | 295°33' | April 1833. | FitzRoy. | -16°53' + 0°16' | -16°37' | At sea. | | -48°46' | 295°36' | Jan. 1834. | FitzRoy. | -19°18' + 0°15' | -19°03' | At sea. | | -42°14' | 295°38' | 1833. | FitzRoy. | -17°45' + 0°17' | -17°28' | Entrance Point. | | -42°58' | 295°41' | 1833. | FitzRoy. | -17°50' + 0°17' | -17°33' | Point Ninfas. | | -42°35' | 295°42' | 1833. | FitzRoy. | -17°50' + 0°17' | -17°33' | Pyramid. | | -42°53' | 295°53' | 1833. | FitzRoy. | -17°50' + 0°17' | -17°33' | Nuevo Head. | | -41°09' | 296°05' | 1833. | FitzRoy. | -17°40' + 0°17' | -17°23' | Belen Bluff. | | -42°03' | 296°12' | 1833. | FitzRoy. | -17°50' + 0°17' | -17°33' | Norte Point. | | -42°46' | 296°24' | 1833. | FitzRoy. | -17°50' + 0°17' | -17°33' | Delgado Point. | | -42°30' | 296°25' | 1833. | FitzRoy. | -17°50' + 0°17' | -17°33' | Valdes Port. | | -40°48' | 297°02' | 1833. | FitzRoy. | -17°00' + 0°17' | -16°43' | Del Carmen Fort. | | -41°02' | 297°15' | 1833. | FitzRoy. | -17°40' + 0°17' | -17°23' | Negro River. | | -45°12' | 297°37' | Dec. 1832. | FitzRoy. | -17°25' + 0°24' | -17°01' | At sea. | | -40°52' | 297°42' | 1833. | FitzRoy. | -17°00' + 0°20' | -16°40' | Raza Point. | | -49°29' | 297°45' | May 1836. | Vaillant. | -19°36' + 0°09' | -19°27' | At sea. | | -49°39' | 297°48' | Mar. 1837. | Du Petit-Thouars. | -17°00' + 0°07' | -16°53' | At sea. | | -40°36' | 297°51' | 1833. | FitzRoy. | -16°30' + 0°18' | -16°12' | Rubia Point. | | -40°46' | 297°54' | Dec. 1832. | FitzRoy. | -15°26' + 0°20' | -15°06' | At sea. | | -40°27' | 298°00' | Aug. 1833. | FitzRoy. | -16°16' + 0°18' | -15°58' | At sea. | | -40°27' | 298°06' | 1833. | FitzRoy. | -16°30' + 0°18' | -16°12' | Snake Bank. | | -45°26' | 298°18' | May 1836. | Vaillant. | -16°52' + 0°12' | -16°40' | At sea. | | -40°52' | 298°23' | Aug. 1833. | FitzRoy. | -16°42' + 0°18' | -16°24' | At sea. | | -47°30' | 298°27' | May 1836. | Vaillant. | -16°16' + 0°12' | -16°04' | At sea. | | -42°16' | 298°28' | Dec. 1832. | FitzRoy. | -16°12' + 0°22' | -15°50' | At sea. | | -43°56' | 298°35' | Dec. 1832. | FitzRoy. | -16°40' + 0°22' | -16°18' | At sea. | | -44°30' | 298°42' | Dec. 1833. | FitzRoy. | -18°14' + 0°20' | -17°54' | At sea. | | -43°14' | 298°43' | Dec. 1832. | FitzRoy. | -16°20' + 0°22' | -15°58' | At sea. | | -41°17' | 298°47' | Aug. 1833. | FitzRoy. | -14°23' + 0°21' | -14°02' | At sea. | | -45°30' | 298°58' | Mar. 1837. | Du Petit-Thouars. | -15°42' + 0°11' | -15°31' | At sea. | | -43°27' | 300°01' | Dec. 1833. | FitzRoy. | -15°46' + 0°26' | -15°20' | At sea. | | -42°44' | 300°29' | May 1836. | Vaillant. | -14°10' + 0°15' | -13°55' | At sea. | | -42°34' | 301°06' | Dec. 1833. | FitzRoy. | -16°01' + 0°30' | -15°31' | At sea. | | -43°05' | 302°50' | Mar. 1837. | Du Petit-Thouars. | -14°10' + 0°14' | -13°56' | At sea. | | -40°30' | 303°07' | May 1836. | Vaillant. | -10°57' + 0°18' | -10°39' | At sea. | | -41°56' | 304°55' | Mar. 1837. | Du Petit-Thouars. | -14°20' + 0°14' | -14°06' | At sea. | | -40°24' | 306°42' | Feb. 1837. | Du Petit-Thouars. | -12°05' + 0°14' | -11°51' | At sea. | | -41°41' | 306°48' | Feb. 1837. | Du Petit-Thouars. | -13°12' + 0°14' | -12°58' | At sea. | | -44°04' | 307°25' | April 1830. | Erman. | -13°40' + 0°49' | -12°51' | At sea. | | -48°49' | 10°16' | Mar. 1843. | Ross. | +24°32' - 0°30' | +24°02' | At sea. | | -48°13' | 10°29' | Mar. 1843. | Crozier. | 23°56' - 0°30' | 23°26' | At sea†. | | -48°27' | 10°51' | Jan. 1845. | Moore and Clerk. | 24°50' - 0°47' | 24°03' | At sea†. | | -44°45' | 13°19' | Jan. 1845. | Moore and Clerk. | 26°34' - 0°47' | 25°47' | At sea†. | | -46°24' | 13°34' | Jan. 1845. | Moore and Clerk. | 25°54' - 0°47' | 25°07' | At sea†. | | -43°36' | 13°47' | Mar. 1843. | Crozier. | 26°40' - 0°30' | 26°10' | At sea†. | | -43°28' | 14°32' | Mar. 1843. | Ross. | 28°18' - 0°30' | 27°48' | At sea†. | | -40°15' | 14°35' | Jan. 1845. | Moore and Clerk. | 27°40' - 0°45' | 26°55' | At sea†. | | -41°51' | 15°03' | Mar. 1843. | Crozier. | 27°05' - 0°30' | 26°35' | At sea†. | | -41°38' | 15°12' | Mar. 1843. | Ross. | 28°40' - 0°30' | 28°10' | At sea†. | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | -53° 33' | 287° 34' | 1834. | FitzRoy. | -23° 35' + 0° 03' | -23° 32' | Crosstide Cape. | | -53° 31' | 287° 35' | 1834. | FitzRoy. | -24° 00' + 0° 03' | -23° 57' | St. Jerome Point. | | -54° 35' | 287° 38' | 1834. | FitzRoy. | -25° 00' + 0° 03' | -24° 57' | West Furies. | | -53° 33' | 287° 41' | 1834. | FitzRoy. | -24° 06' + 0° 03' | -24° 03' | Bachelor River. | | -54° 24' | 287° 42' | 1834. | FitzRoy. | -24° 30' + 0° 03' | -24° 27' | North Cove. | | -54° 02' | 287° 45' | 1834. | FitzRoy. | -24° 00' + 0° 03' | -23° 57' | Bowles Island. | | -53° 11' | 287° 47' | 1834. | FitzRoy. | -23° 45' + 0° 03' | -23° 42' | Gidley Islet. | | -54° 38' | 287° 48' | 1834. | FitzRoy. | -25° 00' + 0° 03' | -24° 57' | East Furies. | | -54° 34' | 287° 48' | 1834. | FitzRoy. | -25° 00' + 0° 03' | -24° 57' | Tusuck Rock. | | -54° 25' | 287° 49' | 1834. | FitzRoy. | -24° 30' + 0° 03' | -24° 27' | Mount Skyring. | | -54° 39' | 287° 53' | 1834. | FitzRoy. | -24° 40' + 0° 03' | -24° 37' | Cape Schomburgk. | | -54° 36' | 287° 55' | 1834. | FitzRoy. | -24° 40' + 0° 03' | -24° 37' | Astrea Island. | | -53° 42' | 287° 59' | 1834. | FitzRoy. | -24° 04' + 0° 03' | -24° 01' | Gallant Port. | | -54° 42' | 288° 05' | 1834. | FitzRoy. | -24° 34' + 0° 04' | -24° 30' | Townshend Harbour. | | -53° 05' | 288° 07' | 1834. | FitzRoy. | -23° 56' + 0° 04' | -23° 52' | Inglefield Island. | | -53° 55' | 288° 10' | 1834. | FitzRoy. | -23° 40' + 0° 04' | -23° 36' | San Antonio. | | -53° 49' | 288° 21' | 1834. | FitzRoy. | -23° 50' + 0° 04' | -23° 46' | Cape Holland. | | -54° 46' | 288° 23' | 1834. | FitzRoy. | -24° 30' + 0° 04' | -24° 26' | Cape Desolation. | | -52° 39' | 288° 29' | 1834. | FitzRoy. | -23° 00' + 0° 04' | -22° 56' | FitzRoy Passage. | | -52° 39' | 288° 30' | 1834. | FitzRoy. | -23° 34' + 0° 04' | -23° 30' | Bennett Point. | | -54° 56' | 288° 32' | 1834. | FitzRoy. | -24° 15' + 0° 04' | -24° 11' | Castlereagh Cape. | | -55° 03' | 288° 37' | 1834. | FitzRoy. | -24° 20' + 0° 05' | -24° 15' | Nicholson Rocks. | | -55° 47' | 288° 41' | 1834. | FitzRoy. | -24° 10' + 0° 05' | -24° 05' | Catherine Island. | | -55° 54' | 288° 42' | 1834. | FitzRoy. | -23° 20' + 0° 05' | -23° 15' | Cape Froward. | | -54° 23' | 288° 43' | 1834. | FitzRoy. | -23° 50' + 0° 05' | -23° 45' | King Island. | | -54° 59' | 288° 50' | 1834. | FitzRoy. | -24° 16' + 0° 05' | -24° 11' | Doris Cove. | | -54° 24' | 288° 52' | 1834. | FitzRoy. | -24° 57' + 0° 05' | -24° 52' | Warping Cove. | | -55° 04' | 288° 52' | 1834. | FitzRoy. | -24° 16' + 0° 05' | -24° 11' | Hat Isle. | | -54° 24' | 288° 53' | 1834. | FitzRoy. | -24° 00' + 0° 05' | -23° 55' | Tarn Cape. | | -57° 35' | 288° 54' | Apr. 1842. | Crozier. | -25° 16' - 0° 02' | -25° 18' | At sea†. | | -55° 08' | 288° 58' | 1834. | FitzRoy. | -24° 15' + 0° 05' | -24° 10' | Treble Island. | | -53° 47' | 289° 02' | 1834. | FitzRoy. | -23° 40' + 0° 06' | -23° 34' | Cape San Isidoro. | | -53° 21' | 289° 02' | 1834. | FitzRoy. | -23° 26' + 0° 06' | -23° 20' | Point St. Mary. | | -53° 38' | 289° 02' | 1834. | FitzRoy. | -23° 40' + 0° 06' | -23° 34' | Port Famine Observatory. | | -53° 38' | 289° 05' | 1834. | FitzRoy. | -23° 00' + 0° 06' | -22° 54' | Point Santa Anna. | | -52° 55' | 289° 12' | 1834. | FitzRoy. | -23° 30' + 0° 06' | -23° 24' | Porpoise Point. | | -52° 47' | 289° 14' | 1834. | FitzRoy. | -23° 29' + 0° 06' | -23° 23' | Packet Harbour. | | -53° 44' | 289° 17' | 1834. | FitzRoy. | -23° 20' + 0° 06' | -23° 14' | Quoin Head. | | -52° 42' | 289° 23' | 1834. | FitzRoy. | -23° 50' + 0° 06' | -23° 44' | Oazy Harbour. | | -52° 49' | 289° 23' | 1834. | FitzRoy. | -23° 50' + 0° 06' | -23° 44' | Elizabeth Island. | | -52° 50' | 289° 25' | 1834. | FitzRoy. | -23° 58' + 0° 06' | -23° 52' | Santa Martha Island. | | -54° 54' | 289° 31' | 1833. | FitzRoy. | -24° 14' + 0° 06' | -24° 08' | Stewart Harbour. | | -53° 20' | 289° 32' | 1834. | FitzRoy. | -23° 00' + 0° 06' | -22° 54' | Cape Monmouth. | | -53° 01' | 289° 33' | 1834. | FitzRoy. | -23° 00' + 0° 06' | -22° 54' | Point Gente Grande. | | -52° 56' | 289° 37' | 1834. | FitzRoy. | -23° 20' + 0° 06' | -23° 14' | Quarter-Master Island. | | -53° 27' | 289° 47' | 1834. | FitzRoy. | -23° 20' + 0° 06' | -23° 14' | Cape Bongainville. | | -52° 39' | 289° 47' | June 1834. | FitzRoy. | -23° 30' + 0° 06' | -23° 24' | Gregory Bay. | | -50° 11' | 289° 50' | Apr. 1834. | FitzRoy. | -21° 00' + 0° 06' | -20° 54' | Junction of Chalia Stream with Santa Cruz. | | -55° 22' | 289° 51' | 1834. | FitzRoy. | -24° 10' + 0° 06' | -24° 04' | Mary Point. | | -52° 45' | 289° 52' | Jan. 1834. | FitzRoy. | -23° 38' + 0° 06' | -23° 32' | At sea. | | -55° 23' | 290° 00' | 1834. | FitzRoy. | -24° 04' + 0° 06' | -23° 58' | March Harbour. | | -55° 27' | 290° 12' | 1834. | FitzRoy. | -24° 00' + 0° 06' | -23° 54' | Nativity Cape. | | -55° 24' | 290° 15' | 1834. | FitzRoy. | -23° 50' + 0° 06' | -23° 44' | Broken Mount. | | -52° 37' | 290° 15' | 1834. | FitzRoy. | -22° 40' + 0° 06' | -22° 34' | St Philip's Bay. | | -58° 58' | 290° 19' | Mar. 1837. | Du Petit-Thouars. | -25° 38' + 0° 03' | -25° 35' | At sea. | MDCCCXLIX. ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | Between the latitudes of $-50^\circ$ and $-60^\circ$ (continued). | | $-52^\circ 27'$ | $290^\circ 32'$ | 1834. FitzRoy. | $-22^\circ 30'$ | $+0^\circ 06'$ | $-22^\circ 24'$ | Orange Cape. | | $-52^\circ 15'$ | $290^\circ 36'$ | 1834. FitzRoy. | $-22^\circ 40'$ | $+0^\circ 06'$ | $-22^\circ 34'$ | Magalhaens Strait. | | $-55^\circ 51'$ | $290^\circ 40'$ | 1834. FitzRoy. | $-24^\circ 10'$ | $+0^\circ 06'$ | $-24^\circ 04'$ | Ildefonso Isles. | | Feb. 1834. FitzRoy. | $-24^\circ 40'$ | $+0^\circ 10'$ | $-24^\circ 30'$ | At sea. | | $-50^\circ 56'$ | $290^\circ 54'$ | 1834. FitzRoy. | $-21^\circ 30'$ | $+0^\circ 11'$ | $-21^\circ 19'$ | Coy Inlet. | | $-50^\circ 51'$ | $290^\circ 55'$ | 1834. FitzRoy. | $-21^\circ 30'$ | $+0^\circ 11'$ | $-21^\circ 19'$ | Redondo Cape. | | $-54^\circ 26'$ | $290^\circ 57'$ | 1834. FitzRoy. | $-22^\circ 50'$ | $+0^\circ 08'$ | $-22^\circ 42'$ | Admiralty Sound. | | $-51^\circ 33'$ | $291^\circ 01'$ | 1834. FitzRoy. | $-21^\circ 47'$ | $+0^\circ 11'$ | $-21^\circ 36'$ | Gallegos River. | | $-55^\circ 36'$ | $291^\circ 02'$ | 1834. FitzRoy. | $-24^\circ 00'$ | $+0^\circ 08'$ | $-23^\circ 52'$ | Mount Beaufoy. | | $-52^\circ 26'$ | $291^\circ 03'$ | 1833. FitzRoy. | $-22^\circ 30'$ | $+0^\circ 13'$ | $-22^\circ 17'$ | Magalhaens Strait. | | Jan. 1845. Sulivan. | $-21^\circ 54'$ | $-0^\circ 10'$ | $-22^\circ 04'$ | Gallegos River. | | $-51^\circ 36'$ | $291^\circ 04'$ | Jan. 1834. FitzRoy. | $-22^\circ 40'$ | $+0^\circ 12'$ | $-22^\circ 28'$ | Cape Possession. | | $-52^\circ 17'$ | $291^\circ 04'$ | 1833. FitzRoy. | $-22^\circ 00'$ | $+0^\circ 13'$ | $-21^\circ 47'$ | Cape Fairweather. | | $-51^\circ 32'$ | $291^\circ 05'$ | 1833. FitzRoy. | $-24^\circ 40'$ | $+0^\circ 14'$ | $-24^\circ 26'$ | Diego Ramirez Isles, N. and S. Rocks. | | Jan. 1833. FitzRoy. | $-21^\circ 00'$ | $+0^\circ 13'$ | $-20^\circ 47'$ | Broken Cliff Peak. | | $-56^\circ 28'$ | $291^\circ 17'$ | 1833. FitzRoy. | $-22^\circ 00'$ | $+0^\circ 13'$ | $-21^\circ 47'$ | Magalhaens Strait. | | $-52^\circ 31'$ | $291^\circ 18'$ | 1833. FitzRoy. | $-20^\circ 54'$ | $+0^\circ 11'$ | $-20^\circ 43'$ | At sea. | | $-50^\circ 15'$ | $291^\circ 29'$ | 1833. FitzRoy. | $-22^\circ 36'$ | $+0^\circ 13'$ | $-22^\circ 23'$ | Dungeness Point. | | Apr. 1834. FitzRoy. | $-20^\circ 54'$ | $+0^\circ 13'$ | $-20^\circ 41'$ | Keel Point. | | $-59^\circ 24'$ | $291^\circ 35'$ | 1833. FitzRoy. | $-22^\circ 30'$ | $+0^\circ 11'$ | $-22^\circ 19'$ | Virgin's Cape. | | $-50^\circ 07'$ | $291^\circ 37'$ | 1833. FitzRoy. | $-22^\circ 54'$ | $+0^\circ 13'$ | $-22^\circ 41'$ | Entrance Mount. | | May 1834. FitzRoy. | $-23^\circ 50'$ | $+0^\circ 11'$ | $-23^\circ 39'$ | Middle Cove (Wollaston Island). | | $-52^\circ 20'$ | $291^\circ 38'$ | 1833. FitzRoy. | $-23^\circ 40'$ | $+0^\circ 13'$ | $-23^\circ 27'$ | Murray Narrow. | | $-50^\circ 09'$ | $291^\circ 40'$ | 1833. FitzRoy. | $-22^\circ 40'$ | $+0^\circ 11'$ | $-22^\circ 29'$ | Cape San Sebastian. | | Feb. 1834. FitzRoy. | $-23^\circ 45'$ | $+0^\circ 13'$ | $-23^\circ 32'$ | Button Island. | | $-55^\circ 35'$ | $291^\circ 31'$ | 1833. FitzRoy. | $-23^\circ 56'$ | $+0^\circ 13'$ | $-23^\circ 43'$ | False Cape Horn. | | $-55^\circ 01'$ | $291^\circ 46'$ | 1833. FitzRoy. | $-23^\circ 40'$ | $+0^\circ 13'$ | $-23^\circ 27'$ | Cape Webley. | | Feb. 1834. FitzRoy. | $-21^\circ 40'$ | $+0^\circ 12'$ | $-21^\circ 28'$ | At sea. | | $-53^\circ 19'$ | $291^\circ 50'$ | 1833. FitzRoy. | $-23^\circ 50'$ | $+0^\circ 13'$ | $-23^\circ 37'$ | Pack Saddle Island. | | $-55^\circ 05'$ | $291^\circ 53'$ | 1833. FitzRoy. | $-23^\circ 56'$ | $+0^\circ 13'$ | $-23^\circ 43'$ | Orange Bay. | | $-55^\circ 43'$ | $291^\circ 54'$ | 1833. FitzRoy. | $-20^\circ 54'$ | $+0^\circ 11'$ | $-20^\circ 43'$ | Port Santa Cruz. | | $-55^\circ 16'$ | $291^\circ 54'$ | 1833. FitzRoy. | $-23^\circ 30'$ | $+0^\circ 10'$ | $-23^\circ 20'$ | Lort Point. | | Jan. 1834. FitzRoy. | $-23^\circ 50'$ | $+0^\circ 10'$ | $-23^\circ 40'$ | Vauverlandt Islet. | | $-52^\circ 07'$ | $291^\circ 55'$ | 1833. FitzRoy. | $-23^\circ 50'$ | $+0^\circ 10'$ | $-23^\circ 40'$ | Sunday Cape. | | Feb. 1833. FitzRoy. | $-24^\circ 20'$ | $+0^\circ 10'$ | $-24^\circ 10'$ | West Point. | | $-55^\circ 24'$ | $291^\circ 56'$ | 1833. FitzRoy. | $-24^\circ 12'$ | $+0^\circ 10'$ | $-24^\circ 02'$ | At sea. | | $-55^\circ 31'$ | $291^\circ 57'$ | 1833. FitzRoy. | $-24^\circ 30'$ | $+0^\circ 15'$ | $-24^\circ 15'$ | Cape Spencer. | | Apr. 1834. FitzRoy. | $-23^\circ 41'$ | $-0^\circ 05'$ | $-23^\circ 46'$ | St. Martin's Cove. | | $-50^\circ 05'$ | $291^\circ 57'$ | 1833. FitzRoy. | $-24^\circ 23'$ | $+0^\circ 15'$ | $-24^\circ 08'$ | St. Martin's Cove. | | Dec. 1832. FitzRoy. | $-22^\circ 00'$ | $+0^\circ 15'$ | $-22^\circ 15'$ | Cape Peñas. | | Oct. 1842. Ross. | $-22^\circ 22'$ | $+0^\circ 10'$ | $-22^\circ 12'$ | At sea. | | Dec. 1832. FitzRoy. | $-23^\circ 00'$ | $+0^\circ 10'$ | $-22^\circ 50'$ | Clay Cliff Narrow. | | May 1834. FitzRoy. | $-23^\circ 45'$ | $+0^\circ 10'$ | $-23^\circ 35'$ | Cape de Roos. | | $-52^\circ 16'$ | $292^\circ 30'$ | 1834. FitzRoy. | $-24^\circ 38'$ | $-0^\circ 05'$ | $-24^\circ 43'$ | At sea†. | | Sept. 1842. Ross. | $-24^\circ 00'$ | $+0^\circ 11'$ | $-23^\circ 49'$ | Cape Horn. | | $-55^\circ 59'$ | $292^\circ 44'$ | 1834. FitzRoy. | $-23^\circ 05'$ | $+0^\circ 11'$ | $-22^\circ 54'$ | At sea. | | Feb. 1834. FitzRoy. | $-22^\circ 00'$ | $+0^\circ 11'$ | $-21^\circ 49'$ | | | $-53^\circ 18'$ | $292^\circ 45'$ | 1834. FitzRoy. | $-21^\circ 31'$ | $+0^\circ 15'$ | $-21^\circ 16'$ | | | Dec. 1832. FitzRoy. | $-19^\circ 58'$ | $-0^\circ 05'$ | $-20^\circ 03'$ | At sea†. | | Nov. 1842. Crozier. | $-23^\circ 25'$ | $+0^\circ 16'$ | $-23^\circ 09'$ | Goree Road. | | Jan. 1833. FitzRoy. | $-23^\circ 20'$ | $+0^\circ 13'$ | $-23^\circ 07'$ | Cape Rees. | | $-55^\circ 05'$ | $292^\circ 59'$ | 1834. FitzRoy. | $-23^\circ 30'$ | $+0^\circ 13'$ | $-23^\circ 17'$ | Deceit Islets. | | Dec. 1832. FitzRoy. | $-21^\circ 35'$ | $+0^\circ 16'$ | $-21^\circ 16'$ | At sea. | | $-52^\circ 06'$ | $293^\circ 02'$ | 1834. FitzRoy. | $-23^\circ 42'$ | $+0^\circ 14'$ | $-23^\circ 28'$ | Terhalten Island. | | May 1836. Vaillant. | $-22^\circ 35'$ | $+0^\circ 09'$ | $-22^\circ 26'$ | At sea. | ### TABLE XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | -55°18' | 293°13' | 1834. | FitzRoy. | -23°4' +0°14' | -23°26' | Lennox Harbour. | | -55°48' | 293°15' | 1834. | FitzRoy. | -23°0' +0°14' | -22°46' | Barneveldt. | | -55°17' | 293°24' | 1834. | FitzRoy. | -23°30' +0°14' | -23°16' | Fifty Point. | | -55°48' | 293°37' | Feb. 1834. | FitzRoy. | -23°31' +0°15' | -23°16' | At sea. | | -54°57' | 294°13' | 1834. | FitzRoy. | -22°50' +0°14' | -22°36' | Aguirre Bay. | | -50°42' | 294°15' | Dec. 1832. | FitzRoy. | -20°41' +0°18' | -20°23' | At sea. | | -56°46' | 294°30' | Apr. 1842. | Crozier. | -20°26' -0°06' | -20°32' | At sea†. | | -56°49' | 294°31' | May 1836. | Vaillant. | -24°11' +0°09' | -24°02' | At sea. | | -54°39' | 294°46' | Dec. 1832. | FitzRoy. | -22°50' +0°19' | -22°31' | Cape San Vicente. | | -51°18' | 294°46' | Dec. 1832. | FitzRoy. | -20°26' +0°19' | -20°07' | At sea. | | -54°48' | 294°46' | Dec. 1832. | FitzRoy. | -22°48' +0°19' | -22°29' | Good Success Bay. | | -54°41' | 294°53' | 1834. | FitzRoy. | -22°50' +0°15' | -22°35' | Cape San Diego. | | -54°48' | 295°15' | 1834. | FitzRoy. | -22°00' +0°15' | -21°45' | Middle Cape. | | -54°54' | 295°15' | 1834. | FitzRoy. | -22°40' +0°15' | -22°25' | Cape St. Bartholomew. | | -54°53' | 295°18' | 1828. | Foster. | -20°32' +0°32' | -20°00' | Franklin Bay. | | -54°48' | 295°19' | 1828. | Foster. | -23°33' +0°32' | -23°01' | Crossley Bay. | | -55°42' | 295°20' | Nov. 1842. | Crozier. | -24°19' -0°08' | -24°27' | At sea†. | | -55°39' | 295°23' | Nov. 1842. | Ross. | -23°41' -0°08' | -23°49' | At sea†. | | -54°47' | 295°27' | 1828. | Foster. | -21°13' +0°32' | -20°41' | Flinders Bay. | | -53°54' | 295°32' | Mar. 1837. | Du Petit-Thouars. | -20°10' +0°07' | -20°03' | At sea (2). | | -54°49' | 295°38' | 1828. | Foster. | -21°43' +0°32' | -21°11' | Port Parry. | | -54°42' | 295°42' | 1834. | FitzRoy. | -22°30' +0°15' | -22°15' | Cape Colnett. | | -50°15' | 295°45' | Apr. 1834. | FitzRoy. | -19°52' +0°15' | -19°37' | At sea. | | -54°50' | 295°47' | 1828. | Foster. | -22°26' +0°32' | -21°54' | Grant Bay. | | -54°39' | 295°54' | 1834. | FitzRoy. | -22°30' +0°15' | -22°15' | New Year Islands. | | -54°46' | 295°57' | 1834. | FitzRoy. | -22°30' +0°15' | -22°15' | Port Cook. | | -54°46' | 295°58' | 1828. | Foster. | -22°15' +0°32' | -21°43' | Observatory. | | -54°43' | 296°17' | 1828. | Foster. | -22°30' +0°32' | -21°58' | Cape St. John. | | -51°57' | 296°36' | Mar. 1837. | Du Petit-Thouars. | -20°16' +0°07' | -20°09' | At sea. | | -55°41' | 296°47' | Sept. 1842. | Crozier. | -24°12' -0°07' | -24°19' | At sea†. | | -53°47' | 297°01' | May 1836. | Vaillant. | -19°56' +0°16' | -19°46' | At sea. | | -50°56' | 297°04' | May 1836. | Vaillant. | -20°38' +0°10' | -20°28' | At sea. | | -50°44' | 297°17' | Mar. 1837. | Du Petit-Thouars. | -19°28' +0°08' | -19°20' | At sea. | | -51°43' | 298°43' | 1834. | FitzRoy. | -20°18' +0°20' | -19°58' | Ship Harbour, Falklands. | | -51°42' | 298°43' | Jan. 1845. | Sullivan. | -19°29' -0°19' | -19°48' | New Island, Falklands. | | -52°01' | 299°00' | Feb. 1845. | Sullivan. | -19°58' -0°19' | -20°17' | Reef Harbour. | | -55°29' | 299°03' | Oct. 1842. | Ross. | -24°33' -0°11' | -24°44' | At sea†. | | -55°32' | 299°12' | Oct. 1842. | Ross. | -21°46' -0°11' | -21°57' | At sea†. | | -51°21' | 299°18' | 1834. | FitzRoy. | -20°24' +0°19' | -20°05' | Stephen's Port, Falklands. | | -51°21' | 299°21' | Jan. 1844. | Sullivan. | -18°29' -0°14' | -18°43' | Hope Harbour, Falklands. | | -51°32' | 299°31' | Nov. 1844. | Sullivan. | -19°07' -0°17' | -19°24' | Whale Cove. | | -52°03' | 299°44' | 1834. | FitzRoy. | -20°00' +0°17' | -19°43' | Port Edgar. | | -54°32' | 299°53' | Oct. 1842. | Crozier. | -22°30' -0°09' | -22°39' | At sea†. | | -51°21' | 299°56' | 1834. | FitzRoy. | -19°35' +0°17' | -19°18' | Port Egmont, Falklands. | | -51°21' | 299°56' | Apr. 1844. | Sullivan. | -18°47' -0°14' | -19°01' | At sea†. | | -54°53' | 299°59' | Oct. 1842. | Ross. | -21°19' -0°09' | -21°28' | At sea†. | | -52°21' | 300°15' | Feb. 1844. | Sullivan. | -18°35' -0°13' | -18°48' | Owen Road, Falklands. | | -55°58' | 300°16' | Apr. 1830. | Erman. | -19°41' +0°30' | -19°11' | At sea. | | -55°07' | 300°19' | Sept. 1842. | Crozier. | -21°56' -0°09' | -22°05' | At sea†. | | -51°20' | 300°30' | Apr. 1844. | Sullivan. | -18°20' -0°15' | -18°35' | Tamar Harbour, Falklands. | | -52°09' | 300°35' | Feb. 1844. | Sullivan. | -18°18' -0°15' | -18°33' | Bay of Islands. | | -52°21' | 300°40' | 1834. | FitzRoy. | -19°50' +0°17' | -19°33' | Bull Road. | | -52°22' | 300°41' | 1834. | FitzRoy. | -19°42' +0°17' | -19°25' | Porpoise Point. | | -53°04' | 300°51' | Nov. 1842. | Ross. | -19°57' -0°09' | -20°06' | At sea†. | 2 h 2 ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | Between the latitudes of $-50^\circ$ and $-60^\circ$ (continued). | | $-52^\circ 12'$ | $300^\circ 56'$ | 1834, FitzRoy. | $-19^\circ 30'$ | $+0^\circ 18'$ | $-19^\circ 12'$ | Adventure Sound. | | $-51^\circ 33'$ | $300^\circ 57'$ | Nov. 1844, Sullivan. | $-17^\circ 56'$ | $-0^\circ 16'$ | $-18^\circ 12'$ | Port San Carlos, Falklands. | | $-52^\circ 16'$ | $301^\circ 06'$ | April 1842, Ross. | $-16^\circ 29'$ | $-0^\circ 09'$ | $-16^\circ 38'$ | At sea. | | $-52^\circ 14'$ | $301^\circ 09'$ | April 1842, Crozier. | $-18^\circ 25'$ | $-0^\circ 09'$ | $-18^\circ 36'$ | At sea. | | $-54^\circ 43'$ | $301^\circ 12'$ | Nov. 1842, Crozier. | $-21^\circ 29'$ | $-0^\circ 09'$ | $-21^\circ 38'$ | At sea. | | $-52^\circ 01'$ | $301^\circ 22'$ | Dec. 1843, Sullivan. | $-18^\circ 14'$ | $-0^\circ 15'$ | $-18^\circ 29'$ | Seal Cove, Falklands. | | $-51^\circ 48'$ | $301^\circ 50'$ | July 1844, Sullivan. | $-16^\circ 52'$ | $-0^\circ 18'$ | $-17^\circ 10'$ | Pleasant Island. | | $-51^\circ 31'$ | $301^\circ 51'$ | Mar. 1843, Sullivan. | $-17^\circ 26'$ | $-0^\circ 13'$ | $-17^\circ 39'$ | Port Louis, Old Settlement. | | $-51^\circ 31'$ | $301^\circ 53'$ | Jan. 1844, Sullivan. | $-17^\circ 16'$ | $-0^\circ 16'$ | $-17^\circ 32'$ | Port Louis. | | $-51^\circ 22'$ | $301^\circ 53'$ | Aug. 1842, Ross. | $-17^\circ 36'$ | $-0^\circ 10'$ | $-17^\circ 46'$ | Port Louis. | | $-51^\circ 32'$ | $301^\circ 53'$ | 1834, FitzRoy. | $-19^\circ 00'$ | $+0^\circ 21'$ | $-18^\circ 39'$ | Port Louis. | | $-51^\circ 30'$ | $302^\circ 06'$ | Mar. 1833, FitzRoy. | $-18^\circ 43'$ | $+0^\circ 24'$ | $-18^\circ 19'$ | At sea. | | $-51^\circ 35'$ | $302^\circ 10'$ | 1834, FitzRoy. | $-19^\circ 00'$ | $+0^\circ 22'$ | $-18^\circ 38'$ | Berkeley Sound, Falklands. | | $-51^\circ 41'$ | $302^\circ 10'$ | Nov. 1844, Sullivan. | $-17^\circ 18'$ | $-0^\circ 19'$ | $-17^\circ 37'$ | Stanley Harbour. | | $-52^\circ 04'$ | $302^\circ 47'$ | Dec. 1842, Ross. | $-17^\circ 49'$ | $-0^\circ 11'$ | $-18^\circ 00'$ | At sea†. | | $-52^\circ 54'$ | $302^\circ 57'$ | Sept. 1842, Crozier. | $-21^\circ 38'$ | $-0^\circ 11'$ | $-21^\circ 49'$ | At sea†. | | $-52^\circ 46'$ | $303^\circ 12'$ | Dec. 1842, Crozier. | $-19^\circ 18'$ | $-0^\circ 11'$ | $-19^\circ 29'$ | At sea†. | | $-52^\circ 50'$ | $303^\circ 12'$ | Dec. 1842, Ross. | $-18^\circ 20'$ | $-0^\circ 11'$ | $-18^\circ 31'$ | At sea†. | | $-56^\circ 53'$ | $303^\circ 21'$ | May 1846, Bérard. | $-18^\circ 16'$ | $-0^\circ 25'$ | $-18^\circ 31'$ | At sea. | | $-55^\circ 05'$ | $303^\circ 22'$ | Sept. 1830, Erman. | $-18^\circ 58'$ | $+0^\circ 30'$ | $-18^\circ 28'$ | At sea. | | $-53^\circ 50'$ | $303^\circ 49'$ | Dec. 1842, Crozier. | $-19^\circ 57'$ | $-0^\circ 11'$ | $-20^\circ 08'$ | At sea†. | | $-53^\circ 56'$ | $303^\circ 52'$ | Dec. 1842, Ross. | $-17^\circ 20'$ | $-0^\circ 11'$ | $-17^\circ 31'$ | At sea†. | | $-53^\circ 55'$ | $304^\circ 18'$ | Sept. 1842, Ross. | $-18^\circ 12'$ | $-0^\circ 08'$ | $-18^\circ 20'$ | At sea†. | | $-54^\circ 05'$ | $304^\circ 26'$ | Sept. 1842, Crozier. | $-20^\circ 49'$ | $-0^\circ 08'$ | $-20^\circ 57'$ | At sea†. | | $-54^\circ 12'$ | $305^\circ 15'$ | Sept. 1842, Crozier. | $-17^\circ 03'$ | $-0^\circ 08'$ | $-17^\circ 11'$ | At sea†. | | $-55^\circ 45'$ | $305^\circ 17'$ | Dec. 1842, Crozier. | $-19^\circ 43'$ | $-0^\circ 08'$ | $-19^\circ 51'$ | At sea†. | | $-55^\circ 46'$ | $305^\circ 17'$ | Dec. 1842, Ross. | $-18^\circ 40'$ | $-0^\circ 09'$ | $-18^\circ 49'$ | At sea†. | | $-55^\circ 15'$ | $305^\circ 39'$ | May 1846, Bérard. | $-17^\circ 19'$ | $-0^\circ 20'$ | $-17^\circ 39'$ | At sea. | | $-54^\circ 33'$ | $306^\circ 13'$ | May 1846, Bérard. | $-14^\circ 14'$ | $-0^\circ 20'$ | $-14^\circ 34'$ | At sea. | | $-56^\circ 36'$ | $306^\circ 38'$ | Dec. 1842, Ross. | $-17^\circ 35'$ | $-0^\circ 09'$ | $-17^\circ 44'$ | At sea†. | | $-56^\circ 54'$ | $306^\circ 41'$ | Dec. 1842, Crozier. | $-19^\circ 13'$ | $-0^\circ 09'$ | $-19^\circ 22'$ | At sea†. | | $-58^\circ 25'$ | $308^\circ 00'$ | Dec. 1842, Crozier. | $-17^\circ 44'$ | $-0^\circ 09'$ | $-17^\circ 53'$ | At sea†. | | $-58^\circ 29'$ | $308^\circ 13'$ | Dec. 1842, Ross. | $-17^\circ 45'$ | $-0^\circ 09'$ | $-17^\circ 54'$ | At sea†. | | $-59^\circ 28'$ | $308^\circ 20'$ | Dec. 1842, Crozier. | $-21^\circ 05'$ | $-0^\circ 09'$ | $-21^\circ 14'$ | At sea†. | | $-59^\circ 54'$ | $308^\circ 28'$ | Dec. 1842, Ross. | $-17^\circ 49'$ | $-0^\circ 09'$ | $-17^\circ 58'$ | At sea†. | | $-52^\circ 52'$ | $309^\circ 34'$ | May 1846, Bérard. | $-14^\circ 02'$ | $-0^\circ 20'$ | $-14^\circ 22'$ | At sea. | | $-57^\circ 30'$ | $351^\circ 40'$ | Mar. 1843, Crozier. | $+10^\circ 29'$ | $-0^\circ 25'$ | $+10^\circ 04'$ | At sea†. | | $-57^\circ 33'$ | $352^\circ 04'$ | Mar. 1843, Ross. | $12^\circ 11'$ | $-0^\circ 25'$ | $11^\circ 46'$ | At sea†. | | $-57^\circ 16'$ | $352^\circ 52'$ | Mar. 1843, Crozier. | $11^\circ 11'$ | $0^\circ 25'$ | $10^\circ 46'$ | At sea†. | | $-57^\circ 06'$ | $352^\circ 53'$ | Mar. 1843, Ross. | $13^\circ 06'$ | $-0^\circ 25'$ | $12^\circ 41'$ | At sea†. | | $-56^\circ 12'$ | $354^\circ 46'$ | Mar. 1843, Crozier. | $12^\circ 05'$ | $-0^\circ 25'$ | $11^\circ 40'$ | At sea†. | | $-56^\circ 15'$ | $354^\circ 56'$ | Mar. 1843, Ross. | $13^\circ 13'$ | $-0^\circ 25'$ | $12^\circ 48'$ | At sea†. | | $-54^\circ 11'$ | $359^\circ 08'$ | Mar. 1843, Ross. | $16^\circ 58'$ | $-0^\circ 25'$ | $16^\circ 33'$ | At sea†. | | $-54^\circ 18'$ | $359^\circ 38'$ | Mar. 1843, Crozier. | $14^\circ 39'$ | $-0^\circ 25'$ | $14^\circ 14'$ | At sea. | | $-59^\circ 02'$ | $4^\circ 09'$ | Jan. 1845, Moore and Clerk. | $17^\circ 30'$ | $-0^\circ 45'$ | $16^\circ 45'$ | At sea†. | | $-55^\circ 29'$ | $5^\circ 54'$ | Jan. 1845, Moore and Clerk. | $21^\circ 23'$ | $-0^\circ 45'$ | $20^\circ 38'$ | At sea†. | | $-53^\circ 52'$ | $6^\circ 12'$ | Jan. 1845, Moore and Clerk. | $21^\circ 24'$ | $-0^\circ 45'$ | $20^\circ 39'$ | At sea†. | | $-52^\circ 56'$ | $7^\circ 53'$ | Jan. 1845, Moore and Clerk. | $23^\circ 46'$ | $-0^\circ 45'$ | $23^\circ 01'$ | At sea†. | | $-51^\circ 47'$ | $9^\circ 34'$ | Jan. 1845, Moore and Clerk. | $23^\circ 37'$ | $-0^\circ 45'$ | $22^\circ 52'$ | At sea†. | | $-50^\circ 45'$ | $10^\circ 18'$ | Jan. 1845, Moore and Clerk. | $23^\circ 55'$ | $-0^\circ 45'$ | $23^\circ 10'$ | At sea†. | Between the latitudes of $-60^\circ$ and $-70^\circ$. | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | $-64^\circ 40'$ | $302^\circ 07'$ | Jan. 1843, Crozier. | $-24^\circ 07'$ | $0^\circ 00'$ | $-24^\circ 07'$ | At sea†. | | $-64^\circ 39'$ | $302^\circ 36'$ | Jan. 1843, Ross. | $-22^\circ 14'$ | $0^\circ 00'$ | $-22^\circ 14'$ | At sea†. | ### TABLE XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|---------|-----------|-----------------------|-----------------------|------------------------|----------| | | | | | | | | | | Between the latitudes of $-60^\circ$ and $-70^\circ$ (continued). | | $-64^\circ 40'$ | $302^\circ 40'$ | Jan. 1843. | Crozier. | $-24^\circ 05'$ | $0^\circ 00'$ | $-24^\circ 05'$ | At sea†. | | $-64^\circ 38'$ | $302^\circ 49'$ | Jan. 1843. | Ross. | $-23^\circ 03'$ | $0^\circ 00'$ | $-23^\circ 03'$ | At sea†. | | $-64^\circ 41'$ | $302^\circ 52'$ | Jan. 1843. | Crozier. | $-23^\circ 52'$ | $0^\circ 00'$ | $-23^\circ 52'$ | At sea†. | | $-64^\circ 32'$ | $302^\circ 55'$ | Jan. 1843. | Crozier. | $-23^\circ 38'$ | $0^\circ 00'$ | $-23^\circ 38'$ | At sea†. | | $-64^\circ 19'$ | $303^\circ 03'$ | Jan. 1843. | Ross. | $-21^\circ 53'$ | $0^\circ 00'$ | $-21^\circ 53'$ | At sea†. | | $-64^\circ 44'$ | $303^\circ 10'$ | Jan. 1843. | Ross. | $-21^\circ 13'$ | $0^\circ 00'$ | $-21^\circ 13'$ | At sea†. | | $-64^\circ 44'$ | $303^\circ 10'$ | Jan. 1843. | Ross. | $-21^\circ 48'$ | $0^\circ 00'$ | $-21^\circ 48'$ | At sea†. | | $-64^\circ 20'$ | $303^\circ 12'$ | Jan. 1843. | Crozier. | $-23^\circ 45'$ | $0^\circ 00'$ | $-23^\circ 45'$ | At sea†. | | $-64^\circ 38'$ | $303^\circ 30'$ | Jan. 1843. | Crozier. | $-23^\circ 05'$ | $0^\circ 00'$ | $-23^\circ 05'$ | At sea†. | | $-64^\circ 31'$ | $303^\circ 38'$ | Jan. 1843. | Ross. | $-22^\circ 53'$ | $0^\circ 00'$ | $-22^\circ 53'$ | At sea†. | | $-64^\circ 05'$ | $303^\circ 47'$ | Jan. 1843. | Ross. | $-22^\circ 05'$ | $0^\circ 00'$ | $-22^\circ 05'$ | At sea†. | | $-64^\circ 15'$ | $303^\circ 49'$ | Jan. 1843. | Ross. | $-21^\circ 07'$ | $0^\circ 00'$ | $-21^\circ 07'$ | At sea†. | | $-64^\circ 11'$ | $303^\circ 50'$ | Jan. 1843. | Crozier. | $-22^\circ 43'$ | $0^\circ 00'$ | $-22^\circ 43'$ | At sea†. | | $-64^\circ 26'$ | $303^\circ 52'$ | Jan. 1843. | Ross. | $-22^\circ 44'$ | $0^\circ 00'$ | $-22^\circ 44'$ | At sea†. | | $-64^\circ 05'$ | $303^\circ 55'$ | Jan. 1843. | Crozier. | $-22^\circ 21'$ | $0^\circ 00'$ | $-22^\circ 21'$ | At sea†. | | $-64^\circ 23'$ | $304^\circ 00'$ | Jan. 1843. | Ross. | $-22^\circ 43'$ | $+0^\circ 03'$ | $-22^\circ 40'$ | At sea†. | | $-64^\circ 06'$ | $304^\circ 03'$ | Jan. 1843. | Ross. | $-21^\circ 10'$ | $+0^\circ 03'$ | $-21^\circ 07'$ | At sea†. | | $-64^\circ 16'$ | $304^\circ 05'$ | Jan. 1843. | Ross. | $-22^\circ 25'$ | $+0^\circ 03'$ | $-22^\circ 22'$ | At sea†. | | $-64^\circ 33'$ | $304^\circ 05'$ | Jan. 1843. | Crozier. | $-22^\circ 23'$ | $+0^\circ 03'$ | $-22^\circ 20'$ | At sea†. | | $-64^\circ 24'$ | $304^\circ 10'$ | Jan. 1843. | Ross. | $-21^\circ 10'$ | $+0^\circ 03'$ | $-21^\circ 07'$ | At sea†. | | $-64^\circ 04'$ | $304^\circ 11'$ | Jan. 1843. | Crozier. | $-22^\circ 40'$ | $+0^\circ 03'$ | $-22^\circ 37'$ | At sea†. | | $-64^\circ 17'$ | $304^\circ 17'$ | Jan. 1843. | Crozier. | $-22^\circ 22'$ | $+0^\circ 03'$ | $-22^\circ 19'$ | At sea†. | | $-64^\circ 04'$ | $304^\circ 18'$ | Jan. 1843. | Ross. | $-21^\circ 02'$ | $+0^\circ 03'$ | $-20^\circ 59'$ | At sea†. | | $-64^\circ 19'$ | $304^\circ 20'$ | Jan. 1843. | Ross. | $-21^\circ 36'$ | $+0^\circ 03'$ | $-21^\circ 33'$ | At sea†. | | $-64^\circ 00'$ | $304^\circ 22'$ | Jan. 1843. | Crozier. | $-22^\circ 54'$ | $+0^\circ 03'$ | $-22^\circ 51'$ | At sea†. | | $-63^\circ 47'$ | $304^\circ 31'$ | Dec. 1842. | Crozier. | $-22^\circ 19'$ | $+0^\circ 03'$ | $-22^\circ 16'$ | At sea†. | | $-64^\circ 17'$ | $304^\circ 42'$ | Jan. 1843. | Crozier. | $-21^\circ 51'$ | $+0^\circ 03'$ | $-21^\circ 48'$ | At sea†. | | $-64^\circ 01'$ | $305^\circ 00'$ | Feb. 1843. | Ross. | $-21^\circ 01'$ | $+0^\circ 03'$ | $-20^\circ 58'$ | At sea†. | | $-63^\circ 49'$ | $305^\circ 00'$ | Dec. 1842. | Ross. | $-22^\circ 27'$ | $+0^\circ 03'$ | $-22^\circ 24'$ | At sea†. | | $-64^\circ 03'$ | $305^\circ 18'$ | Jan. 1843. | Crozier. | $-22^\circ 02'$ | $+0^\circ 03'$ | $-21^\circ 59'$ | At sea†. | | $-64^\circ 12'$ | $305^\circ 20'$ | Feb. 1843. | Crozier. | $-21^\circ 51'$ | $+0^\circ 03'$ | $-21^\circ 48'$ | At sea†. | | $-62^\circ 54'$ | $305^\circ 41'$ | Dec. 1842. | Ross. | $-20^\circ 52'$ | $-0^\circ 02'$ | $-20^\circ 54'$ | At sea†. | | $-64^\circ 20'$ | $306^\circ 00'$ | Jan. 1843. | Crozier. | $-21^\circ 40'$ | $+0^\circ 02'$ | $-21^\circ 38'$ | At sea†. | | $-62^\circ 39'$ | $306^\circ 12'$ | Dec. 1842. | Crozier. | $-21^\circ 30'$ | $-0^\circ 02'$ | $-21^\circ 32'$ | At sea†. | | $-62^\circ 00'$ | $307^\circ 52'$ | Dec. 1842. | Crozier. | $-20^\circ 25'$ | $-0^\circ 02'$ | $-20^\circ 27'$ | At sea†. | | $-62^\circ 18'$ | $308^\circ 03'$ | Dec. 1842. | Ross. | $-19^\circ 03'$ | $-0^\circ 02'$ | $-19^\circ 05'$ | At sea†. | | $-62^\circ 20'$ | $308^\circ 12'$ | Dec. 1842. | Crozier. | $-21^\circ 21'$ | $-0^\circ 02'$ | $-21^\circ 23'$ | At sea†. | | $-64^\circ 10'$ | $309^\circ 30'$ | Feb. 1843. | Crozier. | $-19^\circ 14'$ | $-0^\circ 02'$ | $-19^\circ 16'$ | At sea†. | | $-64^\circ 41'$ | $316^\circ 00'$ | Feb. 1843. | Crozier. | $-15^\circ 43'$ | $-0^\circ 06'$ | $-15^\circ 49'$ | At sea†. | | $-64^\circ 36'$ | $316^\circ 05'$ | Feb. 1843. | Ross. | $-13^\circ 41'$ | $-0^\circ 06'$ | $-13^\circ 47'$ | At sea†. | | $-64^\circ 50'$ | $316^\circ 40'$ | Feb. 1843. | Crozier. | $-15^\circ 01'$ | $-0^\circ 06'$ | $-15^\circ 07'$ | At sea†. | | $-64^\circ 38'$ | $316^\circ 57'$ | Feb. 1843. | Ross. | $-13^\circ 32'$ | $-0^\circ 06'$ | $-13^\circ 38'$ | At sea†. | | $-64^\circ 04'$ | $318^\circ 29'$ | Feb. 1843. | Crozier. | $-13^\circ 59'$ | $-0^\circ 10'$ | $-14^\circ 09'$ | At sea†. | | $-65^\circ 06'$ | $318^\circ 57'$ | Feb. 1843. | Ross. | $-12^\circ 49'$ | $-0^\circ 10'$ | $-12^\circ 59'$ | At sea†. | | $-63^\circ 58'$ | $321^\circ 43'$ | Feb. 1843. | Crozier. | $-10^\circ 13'$ | $-0^\circ 16'$ | $-10^\circ 29'$ | At sea†. | | $-63^\circ 57'$ | $322^\circ 00'$ | Feb. 1843. | Ross. | $-9^\circ 11'$ | $-0^\circ 16'$ | $-9^\circ 27'$ | At sea†. | | $-62^\circ 38'$ | $328^\circ 00'$ | Feb. 1843. | Crozier. | $-7^\circ 30'$ | $-0^\circ 16'$ | $-7^\circ 46'$ | At sea†. | | $-62^\circ 41'$ | $328^\circ 27'$ | Feb. 1843. | Ross. | $-6^\circ 09'$ | $-0^\circ 16'$ | $-6^\circ 25'$ | At sea†. | | $-62^\circ 20'$ | $330^\circ 30'$ | Feb. 1843. | Ross. | $-4^\circ 41'$ | $-0^\circ 16'$ | $-4^\circ 57'$ | At sea†. | | $-62^\circ 09'$ | $332^\circ 38'$ | Feb. 1843. | Crozier. | $-3^\circ 43'$ | $-0^\circ 16'$ | $-3^\circ 59'$ | At sea†. | | $-62^\circ 06'$ | $333^\circ 43'$ | Feb. 1843. | Ross. | $-3^\circ 48'$ | $-0^\circ 25'$ | $-4^\circ 18'$ | At sea†. | | $-62^\circ 00'$ | $333^\circ 44'$ | Feb. 1843. | Crozier. | $-2^\circ 42'$ | $-0^\circ 25'$ | $-3^\circ 07'$ | At sea†. | | $-61^\circ 55'$ | $333^\circ 48'$ | Feb. 1843. | Ross. | $-3^\circ 41'$ | $-0^\circ 25'$ | $-4^\circ 06'$ | At sea†. | | $-61^\circ 32'$ | $335^\circ 33'$ | Feb. 1843. | Crozier. | $-0^\circ 34'$ | $-0^\circ 25'$ | $-0^\circ 59'$ | At sea†. | | $-61^\circ 36'$ | $336^\circ 20'$ | Feb. 1843. | Ross. | $-0^\circ 42'$ | $-0^\circ 25'$ | $-1^\circ 07'$ | At sea†. | | $-70^\circ 43'$ | $343^\circ 12'$ | Mar. 1843. | Crozier. | $2^\circ 01'$ | $-0^\circ 23'$ | $1^\circ 38'$ | At sea†. | ### Table XII. (Continued.) | Lat. | Long. | Date. | Observer. | Observed Declination. | Correction for Epoch. | Corrected Declination. | Remarks. | |------|-------|-------|-----------|-----------------------|-----------------------|------------------------|----------| | -70°50'34"34" | Mar.1843,Ross. | 3°03' -6°23' 2°40' | At sea†. | | -62°18'34"34" | Feb.1843,Crozier. | 3°01' -0°25' 2°36' | At sea†. | | -62°24'34"38" | Feb.1843,Crozier. | 5°00' -0°25' 4°35' | At sea†. | | -62°52'34"33" | Feb.1843,Ross. | 4°49' -0°25' 4°24' | At sea†. | | -64°48'34"16" | Feb.1843,Ross. | 5°11' -0°25' 4°46' | At sea†. | | -69°42'34"20" | Mar.1843,Crozier. | 1°35' -0°23' 1°12' | At sea†. | | -69°13'34"55" | Mar.1843,Ross. | 3°25' -0°23' 3°02' | At sea†. | | -64°29'34"02" | Mar.1843,Ross. | 4°19' -0°25' 3°54' | At sea†. | | -64°06'34"15" | Mar.1843,Crozier. | 5°15' -0°25' 4°50' | At sea†. | | -64°14'34"15" | Feb.1843,Crozier. | 5°01' -0°25' 4°36' | At sea†. | | -66°10'34"40" | Mar.1843,Crozier. | 5°25' -0°25' 5°00' | At sea†. | | -68°30'34"50" | Mar.1843,Crozier. | 3°51' -0°25' 3°26' | At sea†. | | -68°10'34"45" | Mar.1843,Crozier. | 5°18' -0°25' 4°53' | At sea†. | | -68°08'34"10" | Mar.1843,Crozier. | 3°48' -0°25' 3°23' | At sea†. | | -61°16'34"56" | Mar.1843,Ross. | 8°49' -0°25' 8°24' | At sea†. | | -61°16'34"00" | Mar.1843,Crozier. | 7°07' -0°25' 6°42' | At sea†. | | -65°01'34"04" | Feb.1843,Crozier. | 6°34' -0°25' 6°09' | At sea†. | | -65°08'34"50" | Feb.1843,Ross. | 7°35' -0°25' 7°10' | At sea†. | | -67°12'35"36" | Mar.1843,Crozier. | 6°43' -0°25' 6°18' | At sea†. | | -66°00'35"00" | Mar.1843,Crozier. | 8°47' -0°25' 8°22' | At sea†. | | -66°40'35"39" | Mar.1843,Ross. | 8°54' -0°25' 8°29' | At sea†. | | -61°12'9"30" | Feb.1845,Moore and Clerk. | 20°29' -0°40' 19°49' | At sea†. | | -62°03'12"45" | Feb.1845,Moore and Clerk. | 22°07' -0°40' 21°27' | At sea†. | | -61°54'16"40" | Feb.1845,Moore and Clerk. | 23°11' -0°40' 22°31' | At sea†. | | -61°49'19"13" | Feb.1845,Moore and Clerk. | 26°16' -0°40' 25°36' | At sea†. | | -62°05'20"58" | Feb.1845,Moore and Clerk. | 28°05' -0°40' 27°25' | At sea†. | ### CONTENTS. - Introduction .................................................................................................................. 173 - Observations employed:— - A. Sea Observations, uncorrected for the Ship's Magnetism ........................................... 175 - B. Sea Observations, corrected for the Ship's Magnetism .................................................. 176 - C. Land Observations, on Coasts and Islands ..................................................................... 176 - Discussion of the Corrections for the Ship's Magnetism .................................................... 177 - Arrangement of the Observations in Groups ......................................................................... 195 - Table of the Declination in 1840 at the intersection of every 5° of Latitude and Longitude ........ 202 - Table of Secular Change ....................................................................................................... 203 - Comparison with M. Gauss's General Theory ....................................................................... 204 - General Table of the observations employed in the Map arranged according to Latitude and Longitude... 207