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PRESENTS MADE TO THE ROYAL SOCIETY From August 1784 to June 1785; WITH The NAMES of the DONORS. Presents. Donors. 1784. Aug. 12. Oeuvres de Charles Bonnet. Tom. VI. VII. VIII. Neufchatel. 1782, 1783. 4° The Author. —— Essay II. on the Nature and Principles of Public Credit. St. Augustine, East Florida. 1784. fol. S. Gale, Esq. Nov. 4. Description géométrique de la France. Par M. Cassini de Thury. Paris. 1783. 4° The Author. —— Rapport des Commissaires chargés par le Roi de l'examen du Magnétisme Animal. Paris. 1784. 4° The Authors. —— Tableau méthodique des Minéraux. Par M. Daubenton. Paris. 1784. 8° The Author. —— Lettre sur les Expériences des Frictions glaciales pour la guérison de la Peste. Par M. D. Samoïlowitz. Paris. 1781. 8° The Author. —— Lettre à l'Académie de Dijon avec réponse à ce qui a paru douteux dans le Mémoire sur l'Inoculation de la Peste. Par M. D. Samoïlowitz. Paris. 1783. 8° The Author. 1784. Nov. 4. Réponse a M. Gormand, sur la question: "Si les Caustères, peuvent être quelque pré- servatif contre la Peste pendant ses ravages." Par M. D. Samoilowitz. Die bestimmung der Gestalt und Grösse der Erde: von F. W. Gerlach, Wien. 1782. The original Astronomical Observations made in the course of a Voyage to the Northern Pacific Ocean, by Capt. James Cook, Lieut. James King, and Mr. William Bayly. London. 1782. Annals of Agriculture. By Arthur Young, Esq. London. 1784. A Treatise on the Diseases of Children. By Michael Underwood, M. D. Lon- don. 1784. Nov. 11. Dell' Architettura Dialogi: di Ermene- gildo Pini. Milano. 1770. Offervazioni mineralogiche su la Miniera di Ferro dell' Isola d'Elba: di E. Pini. Milano. 1777. Mémoire sur des nouvelles Cristallisations de Feldspath. Par E. Pini. Milan. 1779. Hermenegildi Pini de Venarum metallica- rum excoctione Vol. I. et II. Mediolani. 1779, 1780. Memoria mineralogica sulla Montagna e sui contorni di S. Gottardo: di E. Pini. Milano. 1783. Descrizione di un Pantaulo: di E. Pini. Milano. 1783. Della maniera di osservare nei Monti la dis- posizione degli Strati: di E. Pini. Dell' Elevazione dei principali Monti della Lombardia Austriaca: di E. Pini. Offervazioni mineralogiche sulla Montagna di S. Gottardo: di E. Pini. Mémoires et Obervations de Chimie. Par M. de Fourcroy. Paris. 1784. Observations sur la Cure de la Gonorrhée. Trad. de l'Anglois de M. S.F. Simmons; The Author. The Author. The Commissioners of Longi- tude. The Author. The Author. The Author. The Author. The Author. The Author. The Author. The Author. The Author. The Author. The Author. The Translator. 1784. par Gabriel Masuyer. Montpellier. Nov. II. Medical Communications. Vol. I. London. 1784. Observations on the late Contests in the Royal Society. By Andrew Kippis, D.D. London. 1784. Dec. 9. An Essay on the Use of the Red Peruvian Bark. By Edward Rigby. London. An Essay on the uterine Hemorrhage which precedes the Delivery of the full-grown Fœtus. By E. Rigby. Lond. An Astronomical MS. in the Persian Language. 16. Description des Projets et de la Construction des Ponts, &c. Par M. Perronet. Tom. I. II. Paris. 1782, 1783. fol. Description of a Method of taking the Differences of Right Ascension and Declination with the Reticule Rhomboide of Dr. Bradley. By H.E. Bath. An Enquiry into the various Theories and Methods of Cure in Apoplexies and Palpitations. By B. Chandler, M.D. Canterbury. 1785. A meteorological Journal kept at Fort William, Calcutta. MS. Jan. 13. A Treatise on Time. By W. Watson, jun. M.D. London. 1785. The London Medical Journal. Vol. V. London. 1785. An Essay on Comets. By Andrew Oliver, jun. Salem, New-England. 1772. Feb. 3. Meteorological Journals kept at Nain, Okkak, and Hoffenthal, in Labrador. MS. An Account of the Musical Performances in Commemoration of Handel. By C. Burney, Muf. D. London. 1785. Observations sur la Physique, sur l'Histoire naturelle, et sur les Arts. Par M. l'Abbé Donors. The Society for promoting Medical Knowledge. The Author. The Author. The Author. Major Pierson. The Author. Sir Henry C. Englefield, Bart. The Author. S. F. Simmons, M.D. The Rev. Professor Williams. The Rev. Mr. La Trobe. The Author and the Musical Society. The Editors. 1785. Rozier, et par M. J. A. Mongez lejeune. Tom. XXV. Paris. 1784. 4° Feb. 24. An Inquiry how to prevent the Small-Pox, &c. By John Haygarth, M. B. Chester. 1784. 8° Mar. 10. Remarks on morbid Retentions of Urine. By C. Brandon Trye. Gloucester. 1774. 8° 17. A Portrait of the Elector Palatine Duke of Bavaria. — Quatrième Lettre du Chev. Rosa sur ses Découvertes Physiologiques (translated from the Italian) MS. fol. — Commentarii de Rebus in Scientia naturali et Medicina gestis. Vol. XXV. Lipsiae. 1782. 8° — Connoissance des Temps, pour l'Année 1787. Par M. Jeaurat. Paris. 1784. 12° — Mémoire sur une Machine propre à creuser et curer les Canaux. Rivières ou Ports. Par les Freres F. et A. Eckhardt. 4° — Succinct Account of the Advantages of Mills with inclined float-board Wheels. By Mr. A. G. Eckhardt. fol. April 7. The Theory and Practice of Aerostation. By Tiberius Cavallo. London. 1785. 8° — Observations on the Use of Opium in removing symptoms supposed to be owing to morbid irritability. By Alexander Grant. London. 1785. 4° — Opuscules de Pierre Richer de Belleval. Nouvelle Edition; par M. Broussonet. Paris. 1785. 8° — Lettre sur l'Antiméphitique. Par M. Janin de Combe-Blanche. Vienne. 1783. 8° — Seconde, troisième, et quatrième Lettres à M. Cadet. Par M. Janin de Combe-Blanche. Vienne. 1783, 1784. 8° — L'Homme noyé dans une Fosse, a-t-il péri par le Méphitisme? Lettre par M. Janin de Combe-Blanche. 8° Donors. The Author. The Author. His most serene Highness the Elector Palatine. The Marquis de Hautefort. Mr. Philip Hurlock. The Author. M. A. Eckhardt. The Author. The Editor. The Author. The Author. The Author. 1785. April 7. Preuves que l'Homme s'est noyé dans la fosse; et que le Méphitisme n'a pas causé sa mort. Lettre par M. Janin de Combe-Blanche. 8° Nouvelles Expériences qui confirment celles qui ont été annoncées dans l'Antiméphitique. Par M. Janin de Combe-Blanche. 8° Réponse au Discours de M. O-Rian sur le Magnétisme Animal. Par M. Janin de Combe-Blanche. Genève. 1784. 8° 14. Relief from accidental Death. By Alexander Johnson, M.D. London. 1785. 28. Three Registers of a Pocket Chronometer. By Count De Bruhl. 4° A Memoir on some Improvements in Bookbinding. By M. Anisson le fils (in French) MS. fol. May 5. An Essay on the Nature and Cure of the Phthisis pulmonalis, second edit. By Thomas Reid, M.D. London. 1785. 8° Reports of the Humane Society for the years 1783 and 1784. 8° Account of a Machine constructed for the purpose of deepening and scouring Canals, Rivers, and Ports. By the Brothers F. and A. Eckhardt. fol. 12. Lettres I. II. III. IV. V. VI. sur l'Architecture. Par M. Viel de Saint-Maux. Bruxelles. 1779, 1780. Paris. 1784. 8° 26. Dissertatio Botanica de Sida. Auct. A. J. Cavanilles. Paris. 1785. 4° Observations de M. l'Abbé Cavanilles sur l'Article Espagne de la Nouvelle Encyclopédie. Paris. 1784. 8° Parallèle entre le Magnétisme Animal, l'Électricité, et les Bains medicinaux. Par M. L***. Paris. 1785. 8° Mémoire sur la Décomposition de l'Air atmosphérique par le Plomb. Par M. Luzuriaga. Paris. 1784. 8° Vol. LXXV. Ttt Presents. 1785. May 26. Essays of Reform on the System of the Finances of Great-Britain. By J. Van Der Hey. Vol. I. London. 1785. 4° Reports of the Commissioners appointed to examine, take, and state the Public Accounts of the Kingdom. By John Lane. Vol. II. London. 1785. 4° June 2. Ionian Antiquities. London. 1769. fol. H. M. Marcard Beschreibung von Pyrmont. I. Band. Leipzig. 1784. 8° Mathematical Tables. By Charles Hutton, LL.D. London. 1785. 8° Jacobi Dickson Fasciculus Plantarum cryptogamicarum Britanniae. Londini. 1785. 4° Reflexions on the Study of Nature: translated from the Latin of Linnæus. London. 1785. 8° Donors: The Author. The Commissioners. Society of Dilettanti. The Author. The Author. The Author. J. E. Smith, Esq. AN INDEX TO THE SEVENTY-FIFTH VOLUME OF THE PHILOSOPHICAL TRANSACTIONS. A. ACTINIA. See Barbadoes. Air, Experiments on, by Henry Cavendish, Esq. p. 372. The diminution of the air by the electric spark depends upon the conversion of phlogisticated air into nitrous acid, ibid. Description of the apparatus made use of (tab. XV.), ibid. Fig. 1, 2, and 3. explained, p. 373. Method of forcing the electric spark through the tube, p. 374. Experiments, when the electric spark was passed through common air, included between short columns of a solution of litmus, ibid. When lime-water was used instead of the solution of litmus, ibid. With impure dephlogisticated air, p. 375. Observations on the results of those experiments, ibid. When air was confined by soap-lees, 375—377. Experiments to determine what degree of purity the air should be of, in order to be diminished the most readily, and to the greatest degree, p. 376. Precipitation of a solution of silver by phlogisticated nitre, p. 377. General reasoning upon all the experiments, p. 378—380. Method of preparing the soap-lees, and dephlogisticated air, used in these experiments, p. 380. Quantities of each used therein, p. 381. Experiment to determine whether all the phlogisticated air of the atmosphere is of the same nature, p. 381—382. See Phlogisticated Air. Another cause of the diminution of air by the electric spark, p. 382—384. No phlogiston communicated by the electric spark, p. 384. Air and Water, Experiments and observations relating to, by the rev. Joseph Priestley, LL.D. p. 279. Opinions of Mr. Cavendish, Mr. Watt, and M. Lavoisier, concerning decomposed air, p. 280. The author's opinion of inflammable air, and fixed air, both which had been first advanced by Mr. Kirwan, ibid. Experiment to ascertain whether any water is produced when the air is made to disappear, p. 281. Other experiments of the same kind, p. 282. A peculiar circumstance attending the melting of cast iron with a burning lens, p. 283. Result of melting cast iron in the bottom of a deep glass receiver, p. 284. Mr. Watt's conclusion thereon, ibid. A new and unexpected appearance which occurred in endeavouring to revive the calx of iron, or a calx saturated with pure air, ibid. Experiments to determine whether fixed air or water would be the produce of combining inflammable and dephlogisticated air, p. 285—287. Observation thereon, p. 287. Results of other experiments with the calx of copper, and precipitate, per se, in inflammable air, p. 288. Reflection on the relation of water to inflammable air, and especially Mr. Cavendish's ideas on the subject, ibid. The powerful attraction that charcoal or iron appear to have for water, when they are intensely hot, p. 289. Experiment to ascertain the influence of unperceived moisture in the production of inflammable air, ibid. M. Lavoisier's method of obtaining inflammable air with an hot iron tube and an hot copper tube, p. 290. Result of experiments made with charcoal, p. 291—296. And of others made with iron, p. 297. Observations thereon, p. 298. See Balloons. Experiment to ascertain the quantity of inflammable air which may be obtained from any given quantity of iron, p. 298. The supposition that water consists of two kinds of air endeavoured to be explained, p. 299. Process of that investigation, p. 300. Theory of that process, p. 301. Analogy between the experiment of the calx of iron imbibing inflammable air, and the iron itself imbibing dephlogisticated air, p. 302. Experiments to prove that phlogiston is a real substance capable of assuming the form of air by means of water and heat, p. 303. Cast iron annealed remarkably different from that which has not undergone that operation, p. 304. Experiment with precipitate per se, ibid. Effects of heating iron in all the different kinds of air, p. 305. And of transmitting steam through a copper tube, to try the effects of spirit of wine, ibid. Charcoal of metals explained, p. 306. General inferences from the principal experiments, ibid. Algol, See Variable Star. Opinion of astronomers very unsettled concerning the change of its light, p. 134. Anderson, Mr. James. See Morne Garou. Animal Flower. See Barbadoes. Animals, preserved in spirits, not so fit for anatomical examination, p. 340. Architecture, &c. Sketches and descriptions of three simple instruments for drawing architecture and machinery in perspective, by Mr. James Peacock, p. 366. Directions tions for placing the machines, &c. ibid. Description of the drawing-board (fig. 1. tab. XIII.), ibid. Use of ditto, p. 367. How to draw all perpendicular lines at once, ibid. Description of the compound-board (fig. 2. tab. XIV.), p. 368. Use of ditto, ibid. The T square, its usefulness, p. 369. Description of the vertical-board (fig. 3. tab. XIV.), p. 368. Use of ditto, p. 370. Artificial Spring, account of one, by Erasmus Darwin, M. D. p. 1. Old disused well near the doctor's house in Derbyshire described, p. 2. St. Alkmund's well, its situation, ibid. A new spring discovered, ibid. Method of preventing the mixture of the old water with the new, p. 3. And of trying the height of the new spring, ibid. New water nearly of the same properties with St. Alkmund's well, p. 4. See Mountains. Increase in quantity and quality, ibid. And why, p. 6. Afa Fœtida, description of a plant yielding it, in a letter from John Hope, M. D. p. 36. General description, ibid—38. The afa fœtida plant not satisfactorily known till Kämpfer described it, p. 36. Letter from Dr. Pallas to Dr. Guthrie, with two of the plants, ibid. One of which planted in the Botanic Garden at Edinburgh, p. 39. The juice seems to be of the same nature with the officinal afa fœtida, ibid. Astronomical Observations, in two letters from M. Francis de Zach, Professor of Mathematics, and Member of the Royal Academies at Marseilles, Dijon, and Lyons, p. 137. Account of his observations of an eclipse of the moon, made with Father le Fevre, Astronomer at Lyons, in the Observatory called an grand College, ibid. State of the sky at the time of making the observation, ibid. Short telescopes preferable to long ones in observing eclipses of the moon, p. 138. In eclipses of the moon no greater exactness than that of a minute can be obtained, ibid. Agreement between the Imperial Astronomer, l'Abbé Hell's observations of the moon's spots made at Vienna, with those made by M. Messier at Paris, ibid. Correspondent altitudes of the sun taken with a quadrant of three-foot radius, in order to adjust the pendulum-clock to apparent time, p. 139. Observations of the moon's eclipse the 18th of March, 1783, p. 142. Father le Fevre's observations with a reflector fifty-five inches focal length, p. 143. Observations of Jupiter's satellites at Marseilles, by M. Saint Jacques de Sylvabellia, p. 144. Observation of the transit of Mercury, Nov. 12, 1782, at Marseilles, by the same, p. 151. and by M. Wallot, at the Royal Observatory at Paris, ibid. Important remark upon the diameter of Mercury, p. 152. Averrboa Carambola, an account of the sensitive quality, in a letter from Robert Bruce, M. D. p. 356. Is a species of sensitive plant, ibid. Is differently affected by being touched in different manners, p. 356, 357. Method of confining the motion to a single leaf, p. 357. Effect of impressing it by puncture, percussion, or compression, ibid. Ditto on sticking a pin into the universal petiolus, p. 358. On making a compression with a pair of pincers on ditto, ibid. On the leaves being blown against each other, or the branches, ibid. Appearance of the leaves when shaded from any disturbing cause in the day-time, p. 359. The leaves naturally perform a more extensive... extensive motion when going to sleep than by external impressions in the day-time, ibid. Effects produced on a leaf by the burning lens, ibid. And the electrical shock, p. 360. Two other species of this genus mentioned by Linnaeus, ibid. B Balloons, the cheapest method of filling them with the lightest inflammable air, p. 297. Barbadoes, effects of the dreadful hurricane there in 1780, p. 334. The actinia, or a species of animal flower, then found in considerable numbers on that coast, p. 335. Barker, rev. Robert, B. D. See Stag's Head and Horns. ——— Thomas, Esq. See Barometer, &c. Barometer, Thermometer, and Rain, Abstract of a Register of, at Lyndon, in Rutland, in 1784. By Thomas Barker, Esq. Also of the Rain at South Lambeth, Surrey; and at Selbourn and Fyfield, Hampshire, p. 481. Base, account of the Measurement of a base on Hounslow Heath, by Major-general William Roy, p. 385. Introduction, ibid.—390. The author's acknowledgements of the assistance of several scientific gentlemen, p. 389. 391. 417. 425. Particularly of the worthy President of the Royal Society, p. 425. 458. Choice of the base, tab. XVI. p. 390. First tracing of the base, and clearing of the ground, tab. XVI. p. 391. Soldiers preferred to country labourers, and why, ibid. A detachment encamped near Hanworth Summer-house, ibid. Clearing of the first section of the base, p. 392. Tracing of the second and third sections, p. 393. Half the soldiers quartered in the neighbouring villages to clear the third section, while the remainder smoothed the second, ibid. Instruments made use of in the first and second measurements, p. 394. Steel chain, tab. XVII. ibid. Construction of the chain, ibid. Alteration of the chain, p. 395. Deal rods, tab. XVIII. p. 397. Different opinions concerning the best method of applying rods in measurement, p. 398. Measuring rods and standard rod described, p. 399. Brass standard scale, and method of laying off the lengths of the deal rods, p. 401. Major-General Roy's scale compared with the Society's standard, p. 402. Manner of ascertaining the length of the deal rods with it, p. 403—405. Chests for holding the deal rods and standards, p. 405. Stands for the measuring rods, tab. XVIII. and XIX. p. 406. Method of drawing a line through the air, parallel to the common surface from station to station, in equal distances of 200 yards or 600 feet, as in the figure at the top of tab. XVIII. p. 407. Nature of the moveable stands (towards the right-hand in tab. XVIII. and XIX.) explained, p. 408. Plans of the two tables (towards the right-hand in tab. XVIII.) explained, ibid. Plan of one of the square tables (towards the left-hand of tab. XVIII.) with the ends upon the second and third rods upon it in contact explained, p. 409. Mr. Smeaton's deal platforms, standing on pickets driven into the ground, and properly levelled (tab. XIX.) described, p. 410. Boning telescope and rods, tab. XVIII. p. 411. Method of tracing the line of 200 yards, &c. from one fixed hand to the other, ibid. Boning telescope telescope described, ibid. Boning rods, and their use, described, p. 412. Cup and tripod for preserving the point upon the ground, where the measurement was discontinued at night, and resumed next morning, p. 412. Difference between measuring with a rod of twenty feet, and with rods of twenty feet three inches, p. 412. Brass cup used on these occasions described, p. 413-415. Nature of the tripod (tab. XVIII.) explained, p. 413. Method of suspending the plummet from any part of the deal rods indifferently, p. 414. Wheels for terminating, in a permanent manner, the extremities of the base, tab. XVII; ibid. Mr. Myne's improved machines for certainly referring to the same point on any occasion of correcting or repeating the work (represented in tab. XVIII.), p. 415. Rough measurement of the base with the chain, and determination of the relative heights of the stations by means of the telecopic spirit level (tab. XVI. and XVII.), p. 416. The first measurement of the south-east section of the base completed in three hours and a half, p. 417, 418. The same section re-measured, with the probable cause of the variation, p. 418. The operation with the chain suspended, and why, p. 419. Description of a hold-fast for the rear-end of the chain, invented by Col. Pringle (represented by two elevations adjoining in tab. XVII.), ibid. The operations resumed by measuring twice with the chain forwards and back again the second section of the base, ibid. The level of the first and second section of the base taken, with an account of the spirit-level made use of, p. 420. The first general table relating to the levels of the base explained, ibid. p. 421. Col. Calderwood's method of computing the difference between the hypothenusal distances of 600 feet each, and the reduced base distances, p. 420. Tracing of the base with the transit instrument, p. 421, 422. Consequence of delaying the use of that instrument, p. 422. Levels of the third section taken, and the rough measurement thereof with the chain completed, p. 422, 423. Result of the examination of the length of the chain in different temperatures, p. 423. Descent from the lower end of the base to the surface of the Thames at Hampton, p. 424. Measurement of the base with the deal rods, p. 425. Method of performing that operation, p. 426. Difference of measuring by coincidences and contacts accounted for, p. 427. The two first hypothenuses re-measured, with the result, p. 428. Their Majesties prevented by the weather from seeing the nature of the operations, p. 429. Method of discovering the error of the chain at each station, p. 429. Inconveniences occurring from the humid and dry state of the atmosphere, &c. p. 430. See Expansibility. Different comparisons of the rods with the standard, and the result, p. 433, 433. Near agreement between the result by the deal rods, and that furnished by the rough measurement with the chain, accounted for, p. 433. Measurement with the deal rods finished, ibid. Expansion of the deal rods, p. 434—436. See Riga Redwood, Deal Rods. Mr. Ramden's observations of the different expansions, p. 435. Operations on Hounslow-Heath totally suspended, p. 438. Comparison made in the beginning of September at Spring Grove, when the rods were in their dry or contracted state, and the remeasure- ment of the same space the next morning, when, being left out on purpose, they had contracted all the humidity they could, p. 439, 440. Description of the glass rods, ultimately used to determine the length of the base, tab. XIX. p. 441—449. The case containing the tube described, p. 441. Manner in which the middle of the tube is made fast to the middle of the case, p. 442. Fixed and moveable ends of the tube described, p. 443. Fixed and moveable apparatus described, p. 444—447. Mahogany lid on the top of the case described, p. 447. Method of ascertaining the length of the glass rods, p. 448. Disposition of the stands for the double measurement with the chain and glass rods; description of the apparatus then applied to the ends of the chain; and ultimate continuation of the measurement with the glass rods alone, tab. XVII. and XIX. p. 449. Reasons for rejecting the deal rods, ibid. Commencement of the operation for the double measurement, p. 450—453. Apparatus attached to the first end of the chain, p. 451. Ditto for the last end (to the right-hand side of tab. XVII.), p. 452. Comparison of the contraction of steel and glass, with the error of the chain in defect, p. 454. Farther experiments with the chain given up, and why, p. 455. His Majesty honours the operation with his presence, p. 456. Equation of the deal rods and of the glass rods, on 3100 feet, ibid. Difference over-rated in the expansion of the 560 deal rods, p. 457. Measurement with the glass rods completed, p. 458. Equation of the 1370 deal rods and of the 1370 glass rods, with the difference over-rated in the total expansion of the deal rods, p. 459. Conjecture concerning the cause of the estimated and real expansion of the deal rods, ibid. p. 460. Description of the microscopic pyrometer, used for determining by experiment the expansion of the metals concerned in the measurement of the base, tab. XX. p. 461—472. The microscopic pyrometer (tab. XX.) described, p. 462—472. Use and description of the fixed microscope, p. 466. Ditto of the micrometer, p. 467. Use of two eye glasses in microscopes, p. 468. Scale of the pyrometer explained, p. 469. Account of the experiments with the pyrometer, p. 472—476. Ultimate determination of the base on Hounslow Heath, p. 476—478. General table of the base, shewing the relative heights of the stations above the south-east extremity near Hampton Poor house, the reduction of the hypotenuses, and the correction for the temperature of the glass rods, whereby the true length is obtained in the heat of 62 degrees, p. 479. Table of the expansion of metals, deduced from experiments made with the microscopic pyrometer in 1785, p. 480. Bladk, Mr. See Specific Gravities. Bouguer. See Specific Gravities. Bredon, Leicestershire, observations on the lime-mountain there, p. 4. Brook, Mr. See Vacuum. Bruce, Robert, M.D. See Averrhoa Carambola. Burning Mountains. See Morne Garou, Caribbee Islands. C. Calderwood, Calderwood, Col. See Bafe. Caribbee Islands, reasons for supposing a communication between the burning mountains in them and the volcanos on the high mountains in America, p. 30. Shocks of earthquakes frequent near them, ibid. Cavendish, Henry, Esq. See Air. Combustion, Observations and Experiments on the Light of Bodies in a State of, by the Rev. Mr. Morgan, p. 190. Data to be attended to, ibid. Conclusion drawn from them, ibid. Manner in which the rays of light escape, when decomposed by heat, p. 191. Observations on the flame of a candle, p. 192. The best mode of shewing the escape of some rays by that degree of heat which will not separate others till increased, p. 193. Mr. Melvill's mode of examining bodies whilst on fire, ibid. Besides the increase or decrease of heat, there are other modes of retarding or accelerating the combustion of bodies, p. 194. Singularities in the colours of different flames accounted for, p. 195. Singular phenomenon attending a burning body explained, p. 196. Imperfection in Sir Isaac Newton's definition of flame, p. 197. Experiments on electric light, p. 198—206. General deductions useful in procuring any degree of certainty in any hypothesis, p. 198. Observations on phosphoric light, p. 208. Mr. Wilson's theory of the slow combustion of shells, ibid. Objections to that theory, p. 209—211. Postscript by Dr. Price, p. 211. Construction of the Heavens, on the, by William Herschel, Esq. p. 213. Two opposite extremes to be avoided, if we hope to make any progress in an investigation of this delicate nature, ibid. Theoretical view of the universe, p. 214. Formation of nebulae, ibid. Objections considered, p. 216. Optical appearances considered, p. 217—219. Result of observations, p. 219. The theoretical view of the universe, p. 214. Shewn to be perfectly consistent with facts, p. 220. I. Table of star-gages, p. 221—240. Problem, the stars being supposed to be nearly scattered, and their number, in a field of view of a known angular diameter being given, to determine the length of the visual ray, p. 241. The same otherwise, p. 243. We inhabit the planet of a star belonging to a compound nebula of the third form, p. 244. Difference between a crowd and a cluster of stars, p. 246. Use of the gages, p. 250. Table II. p. 252. Section of our sidereal system, p. 253. The origin of nebulous strata, p. 254. An opening in the heavens described, p. 256. Phenomena at the poles of our nebula, p. 257. Enumeration of very compound nebulae or milky ways, p. 258. Some very remarkable nebulae pointed out, ibid. Several extended nebulae described, p. 260—262. A perforated nebula or ring of stars, p. 263. Planetary nebulae, p. 263—266. D. D'Alembert. See Rotatory Motion. Darwin, Dr. Erasmus. See Artificial Spring. Deal Rods, table of the expansion of, with observations, p. 437. Are improper for very accurate measurement, p. 438. De la Lande. See Wires. De Luc, Mr. See Specific Gravities. Double Stars. Catalogue of, by William Herschel, Esq. p. 40. Method of pointing out those stars in this collection which are not in Mr. Flamstead's Catalogue, p. 41. and of applying it, ibid. Precaution to be observed where other stars are very near those to be pointed out, p. 42. The observer should be furnished with Flamstead's Coelestial Atlas, which must have the stars marked from the author's Catalogue, p. 43. Precaution in relation to examining the closest of the double stars, ibid. All the observations in this Catalogue are supposed to be made with a power of 460, unless marked otherwise, p. 45. Method of taking the measures of the distances, ibid. See Micrometer. Catalogue of double stars, p. 47. First class, ibid.—p. 65. Second class, p. 65—78. Third class, p. 78—90. Fourth class, p. 91—105. Fifth class, p. 105—118. Sixth class, p. 118—126. Additional errata to the Catalogue of Double Stars in vol. LXXII, p. 126. See Variable Star. E. Eagle-stone. See Router. Earthquakes. See Caribbee Islands. Eclipses. See Astronomical Observations. Equatorial Micrometer, Mr. Smeaton's recommended, p. 348. Euler, M. Leonhard. See Rotatory Motion. —— M. John Albert. See Ditto. Expansibility, observation on that of glass, with Mr. Cumming's pyrometer, p. 431. See Deal Rods. F. Ferguson. See Friction. Fix'd Air and Water appear to consist of the same ingredients, p. 296. See Air. Fordyce, George, M. D. See Weight. Friction, on the Motion of Bodies affected by, by the Rev. Samuel Vince, A. M. of Cambridge, p. 165. This branch of natural philosophy, notwithstanding its importance. portance to the practical mechanic, has been, of all others, the most neglected, ibid. Musschenbroeck's, Helfham's, and Ferguson's opinions of the law by which the motions of bodies are retarded by friction, p. 166. Euler's theory not true, ibid. Experiments to determine different properties of friction, ibid. p. 167. The friction of hard bodies in motion is a uniformly retarding force, p. 169. Experiments to determine whether friction, *ceteris paribus*, varies in proportion to the weight or pressure, p. 170—172. Observations thereon, ibid. Experiments proving that the friction of a body does not continue the same when it has different surfaces applied to the plane on which it moves, but that the smallest surface will have the least friction, p. 170—175. Result of the author's examination into the nature of the experiments which have been made by others, p. 176. Theory established upon the principles already deduced, p. 178. Prop. I. to find the time of descent and the number of revolutions of a cylinder, or that circular section of a body on which it rolls down an inclined plane in consequence of its friction, ibid. Cor. 1. p. 179. Cor. 2. ibid. Cor. 3. ibid. Cor. 4. p. 180. Cor. 5. ibid. Prop. II. the body being projected on an horizontal plane, with a given velocity, to determine the space through which the body will move before it stops, or before its motion becomes uniform, p. 181. Case I. ibid. Case II. p. 182. Case III. p. 184. Definition of the centre of friction, p. 186. Prop. III. to find the centre of friction, ibid. Prop. IV. given the velocity with which a body begins to revolve about the centre of its base, to determine the number of revolutions which the body will make before all its motion be destroyed, p. 187. Prop. V. to find the nature of a curve described by any point of a body affected by friction, when it descends down any declined plane, p. 188. G. Goodricke, John, Esq. See Variable Star. H. Hales, Dr. mistake of his, p. 271. Heat, diminishes the attractions of cohesion, chemistry, magnetism, and electricity, p. 364. Hell, Abbé. See Astronomical Observations. Helfham. See Friction. Herschel, William, Esq. See Double Stars, Construction of the Heavens. Home, Mr. Everard. See Marine Animal. Hope, John, M.D. See Asa Fataida. Hunter, John, Esq. See Marine Animal. I. Jalbip, in Lancashire, manner of digging for water there, p. 6. K. Kirwan, Richard, Esq. See Specific Gravities. L. Landen, Mr. John. See Rotatory Motion. Larkell river, has not the property of incrustation, p. 354. Lavoisier, M. See Air and Water. Leach, has no anus, p. 341. Le Fevre. See Astronomical Observations. Lightfoot, Rev. John. See Motacilla. M. Machinery in Perspective. See Architecture. Marine Animal, Description of a new one, in a Letter from Mr. Everard Home, Surgeon, to John Hunter, Esq.; with a Postscript by Mr. Hunter, containing anatomical Remarks upon the same, p. 333. Reasons for believing this animal to be a nondescript, ibid. Where and when found, p. 334. See Barbadoes. By whom first observed, p. 335. Description of, ibid.—339. Postscript, by John Hunter, Esq., p. 340—343. See Animals. Anatomical division of the animal, p. 340. Its stomach and intestine described, p. 341. Differs materially from most animals with tentacula, ibid. See Leach, Polypi, Univalve Fish. Manner of voiding its excrements, p. 342. Enquiry into the manner of increasing its shell, ibid. Where most probable to be found, p. 343. Explanation of the figures, tab. XI. fig. 1. p. 344. Fig. 2. ibid. Melvill, Mr. See Combustion. Messier, M. See Astronomical Observations. Metors, are probably owing to an accumulation of electricity, p. 278. Micrometer, improvement in Messrs. Nairne and Blunt's, p. 46. See Base. Microscope. See Base. Morgan, Rev. Mr. See Combustion. —— Mr. William. See Vacuum. Morne Garou, a Mountain in the Island of St. Vincent, Account of, with a Description of the Volcano on its summit, in a Letter from Mr. James Anderson, Surgeon, p. 16. Difficulties in exploring the interior parts of the mountain, ibid. Which has also been mentioned to have had volcanic eruptions from it, ibid. Of which, on examination, several indications appeared, p. 17. The author's friendly reception at Mr. Maloune's (where he lay) about a mile from the mountain, ibid. Arrives at the bottom of the mountain, attended by two negroes of Mr. Maloune's and a boy, p. 18. After climbing a rock, forty feet high, they come to some clear ground, belonging to a Mr. Gasco, ibid. Who receives them kindly, p. 19. See West Indies. Return to Mr. Gasco's, being unable to get forward, p. 20. Description and situation of his hut, ibid. Difficulties Mr. Anderson encountered in his second attempt, p. 21. Arrives at the bottom of a very high precipice, ibid. His dangerous situation on gaining the top, p. 22. Meets four negroes from Mr. Maloune's, with provisions, p. 23. Discovers a ravine by which he might have gained the summit of the mountain with little difficulty, ibid. After a most disagreeable night on the mountain, gets a sight of the summit, p. 25. With a description of it, ibid. Two negroes leaving him, and the rest refusing to proceed, he is forced to return, p. 25, 26. Sets out again, accompanied by Mr. Fraser, and attended by two negroes, p. 26. Finds some beautiful plants and moss (of which he saw none else in the West Indies) in great abundance, ibid. Gains the summit, with a description of the awful appearance of the excavation there, p. 27, 29. Burning mountain at the bottom thereof described, p. 27. Various minerals found on all parts of the mountain, p. 28. Author's reasons for supposing it has but lately begun to burn, ibid. Two chalybeate lakes on the sides of the crater, and a conjecture on the manner of their being supplied, ibid. Singular motion of the clouds on the mountain, p. 29. See Caribbee Islands. References to the figure, p. 31. Motacilla, Account of an English Bird of that Genus, supposed to be hitherto unnoticed by British Ornithologists, observed by the Rev. John Lightfoot, p. 8. Generic characters, ibid. Marks evincing it to be of the species of Motacilla, p. 10, 11. Named after the Linnaean manner, p. 11. Sepp the only author who can be suspected of noticing this bird, p. 12. Which may not improperly be denominated the Reed Wren, ibid. Its haunts, ibid. Its food and note, p. 13. Its nest, ibid. Materials and situation of its nest, ibid. Number and description of its eggs, p. 14. Conjectured to be a migrating bird, ibid. Mountains, theory of the formation of, p. 4—7. Myne, Mr. See Bate. N. New England white-wood. See Riga red-wood. Newton, Sir Isaac. See Combustion. Nitre, when much phlogisticated, is capable of making a precipitate with a solution of silver, p. 378. P. Peacock. Peacock, Mr. James. See Architecture, &c. Phlogisticated Air, whether many different substances are not in reality confounded together under this name, p. 381. Phlogiston. See Air. Phosphoric Light. See Combustion. Pigott, Edward, Esq. See Variable Stars. Polypus, has no anus, p. 341. Price, Dr. See Combustion. Priestley, Rev. Joseph. See Air, and Water. Pringle, Col. See Base. Pyrometer. See Base. Rain. See Barometer, &c. Ramfden, Mr. his curious beam compasses, p. 402. See Base. His easy and simple way of obtaining the scale of his pyrometer, p. 471. Reed-wren. See Motacilla. Richmond, in Surrey, method of boring for water there, p. 6. Riga Red-wood, more susceptible of the effects of moisture than New-England white wood, p. 435. Rotatory Motion. Of the Rotatory Motion of a Body of any Form whatever, revolving, without Restraint, about any Axis passing through its Center of Gravity, by Mr. John Landen, p. 311. When the axis, about which a body is made to revolve, is not a permanent one, the centrifugal force of its particles will disturb its rotatory motion, &c. p. 312. To determine in what track, and at what rate, the poles of such momentary axis will be varied, not an uninteresting proposition, ibid. The solutions of that problem by M. Leonhard Euler, M. D'Alembert, and M. John Albert Euler, rectified by the author, ibid. Difference between him and the above gentlemen concerning the angular velocity and the momentum of rotation, p. 313. How to find a parallelopipedon that being by some force or forces made to revolve about an axis, with a certain angular velocity, shall move exactly in the same manner as any other given body, if made to revolve with the same force, about an axis passing through its centre of gravity, p. 315. Tab. X. fig. 1. explained, ibid. Method of finding how a parallelopipedon will revolve about successive momentary axes passing through its center of gravity, p. 318. Fig. 2. and 3. explained, p. 318. 322. Fig. 4. ditto, p. 321. Fig. 5. ditto, ibid. Errors of M. Euler pointed out, p. 327, 328. To which M. D'Alembert's seem nearly similar, p. 328. Router, or Eagle-stone mountain in the Peak, its volcanic origin, p. 5. Roy, Major General William. See Base. S. Scobenus Lithofermos, a species of grass in the West Indies, p. 15. Sensitive Plant. See Averrhoa Carambola. Sepp. See Motacilla. Shells. See Combustion. Smeaton, Mr. See Equatorial Micrometer, Base. Specific Gravities, Remarks on, taken at different Degrees of Heat, and an easy Method of reducing them to a common Standard, by Richard Kirwan, Esq. p. 267. Usefulness of a comparative view of the weights of equal volumes of water, &c. ibid. A capital advantage derivable from a table of specific gravities, ibid. Instrument for making experiments described, p. 268. Table of specific gravities, p. 269. Remarks and observations by Bouguer, Mr. Bladh, Mr. De Luc, &c. p. 270. Advantages of this method pointed out, p. 271. Stag's Head and Horns, Account of, found at Alport, in the Parish of Youlgreave, in the County of Derby. In a Letter from the Rev. Robert Barker, B.D. p. 353. Place and manner of discovering them, ibid. Not supposed to belong to a very old animal, p. 354. Are of the throstle-neft species, &c., see Throstle-neft Horns. Conjecture how they were deposited where found, ibid. See Larkell. Dimensions of the horns found at Alport, p. 355. Ditto of a large pair of throstle-nefts horns, ibid. Ditto of the horns of a seven-years old stag, ibid. Summation of Infinite Series, Supplement to the Third Part of the Paper on, in 1782, by the Rev. S. Vince, M.A., p. 32. Sylvabelle, M. Saint Jacques. See Astronomical Observations. T. Telescopes. See Astronomical Observations, Wires. Tentacula, animals with tentacula consist of an almost infinite variety, p. 343. Terebella, a double-coned one, found by Mr. Cordiner, at Bamff, in Scotland, p. 343. Thermometer. See Barometer, &c. Throstle-neft Horns, described, p. 354. Tuft, a kind of stone, described, p. 353. U. Vacuum, Electrical Experiments made in order to ascertain the non-conducting Power of a perfect one, &c. by Mr. William Morgan, p. 272. Conclusion drawn from Mr. Walmsley. Walsh's experiments in the double barometer tube, not universally admitted, ibid. Account of the author's experiments to determine its truth or fallacy, ibid. Tab. IX. fig. 1. explained, ibid. Account of various electrical experiments, p. 274, 276. Mr. Brook's method of making mercurial gages, p. 276, 277. See Meteors. Variable Star, Observations on a new one, in a Letter from Edward Pigott, Esq. p. 127. Use of verifying stars supposed to be variable, ibid. Variation of the star n Antinoi very similar to that of Algol, though not exactly the same in any particular, ibid. Changes undergone by n Antinoi, p. 128. Order of the stars to which it was compared, ibid. Greater difference between the brightness of many stars in twilight and moon-light, or the least hazy air, than in a dark and clear sky, ibid. Journal of observations of n Antinoi, p. 129. Natural method of obtaining a point of comparison for settling its periodical changes, p. 131. Computations (the rough length of a single period being found) to obtain greater exactness, p. 132. Method of determining the time when n Antinoi was between its least and greatest brightness, ibid. Observations on its decreasing brightness in 1783 compared with corresponding ones made in 1784, p. 134. Results of those comparisons, ibid. Account of several attempts to determine the relative brightness of stars, p. 135, 136. Observations on a new one, by John Goodricke, Esq. p. 153. The star β Lyrae discovered to be variable, ibid. Eight points of its variation in twelve days and nineteen hours, p. 154. Its relative brightness at its obscuration in the third and seventh points, ibid. p. 161. Magnitudes of the stars to which it was compared during the progress of its variation, p. 155. Series of observations of its brightness and magnitude, ibid. Observations thereon, p. 161. Calculation of the times of the middle of its obscuration in the third point, p. 162. Remarks thereon, ibid. Mr. Herschel reckons β or γ Lyrae amongst those stars which he supposes to have undergone an alteration, p. 163. Vince, Rev. Samuel, M. A. See Summation of Infinite Series, Friction. Univalve Fish, their internal formation, p. 342. W. Wallot, M. See Astronomical Observations. Walsh, Mr. See Vacuum. Watt, Mr. See Air and Water. Weight, An Account of some Experiments on the Loss of, in Bodies on being melted or heated. By George Fordyce, M.D. p. 361. Several experiments made by the Doctor, which not being contradictory, are not worth laying before the Society, ibid. Account of a conclusive one in determining the loss of weight in ice when thawed, and on being heated, ibid. p. 363. Conjectures of the cause of the acquisition of weight on water's being converted into ice, p. 363. Method to determine which is true, ibid. Experiment to ascertain whether there is matter absolutely light; or which repels repels instead of attracting other matter, p. 364. See Heat. Conjecture on the increase of the weight of ice on being cooled, ibid. West Indies, difficulty of going through the woods there, p. 19. Wilson, Mr. See Combustion. Wires, A Description of a new System of, in the Focus of a Telescope, for observing the comparative Right Ascensions and Declinations of celestial Objects; together with a Method of investigating the same, when observed by the Rhombus, though it happen not to be in an equatorial Position, by the Rev. Francis Wollaston, LL.B., p. 346. The author twice disappointed in attempting to ascertain the right ascensions and declinations of the stars he had laid down, p. 346, 347. The rhombus is very good in theory, but seldom true enough to be depended on, p. 347. A very small error in observing the passage of a star makes a very material difference in the result, ibid. Trial with a square placed angularly, which seems to answer better, ibid. See Equatorial Micrometer. Tab. XII. fig. 1. explained, p. 347. Properties and advantages of the square preferably to the rhombus, p. 348. Method of rectifying the erroneous position of the instrument by the formula given by M. De la Lande in his Astronomy, p. 349. Formula constructed by the author's son, for investigating the comparative right ascensions and declinations of stars, ibid. Application of the formula, p. 351. How to deduce the angle of deviation from the true equatorial position in the new system of wires, p. 352. Wollaston, Rev. Francis, LL.B. See Wires. Z. Zach, Francis de. See Astronomical Observations. FROM THE PRESS OF J. NICHOLS. VOL. LXXV.