Front Matter

ADVERTISEMENT. The Committee appointed by the Royal Society to direct the publication of the Philosophical Transactions, take this opportunity to acquaint the Public, that it fully appears, as well from the council-books and journals of the Society, as from repeated declarations, which have been made in several former Transactions, that the printing of them was always, from time to time, the single act of the respective Secretaries, till the Forty-seventh Volume: the Society, as a body, never interesting themselves any further in their publication, than by occasionally recommending the revival of them to some of their Secretaries, when, from the particular circumstances of their affairs, the Transactions had happened for any length of time to be intermitted. And this seems principally to have been done with a view to satisfy the Public, that their usual meetings were then continued for the improvement of knowledge, and benefit of mankind, the great ends of their first institution by the Royal Charters, and which they have ever since steadily pursued. But the Society being of late years greatly enlarged, and their communications more numerous, it was thought adviseable, that a Committee of their members should be appointed to reconsider the papers read before them, and select out of them such, as they should judge most proper for publication in the future Transactions; which was accordingly done upon the 26th of March 1752. And the grounds of their choice are, and will continue to be, the importance and singularity of the subjects, or the advantageous manner of treating them; without pretending to answer for the certainty of the facts, or propriety of the reasonings, contained in the several papers so published, which must still rest on the credit or judgment of their respective authors. It is likewise necessary on this occasion to remark, that it is an established rule of the Society, to which they will always adhere, never to give their opinion, as a body, upon any subject, either of Nature or Art, that comes before them. And therefore the thanks, which are frequently proposed from the chair, to be given to the authors of such papers, as are read at their accustomed meetings, or to the persons through whose hands they receive them, are to be considered in no other light than as a matter of civility, in return for the respect shewn to the Society by those communications. The like also is to be said with regard to the several projects, inventions, and curiosities of various kinds, which are often exhibited to the Society; the authors whereof, or those who exhibit them, frequently take the liberty to report, and even to certify in the public newspapers, that they have met with the highest applause and approbation. And therefore it is hoped, that no regard will hereafter be paid to such reports, and public notices; which in some instances have been too lightly credited, to the dishonour of the Society. CONTENTS OF VOL. LXVIII. PART I. I. A LETTER from Sir William Hamilton, K. B. F. R. S. to Sir John Pringle, Bart. P. R. S. giving an Account of certain Traces of Volcanos on the Banks of the Rhine. page 1 II. Of the Heat, &c. of Animals and Vegetables. By Mr. John Hunter, F. R. S. p. 7 III. The Force of fired Gun-powder, and the initial Velocities of Cannon Balls, determined by Experiments; from which is also deduced the Relation of the initial Velocity to the Weight of the Shot and the Quantity of Powder. By Mr. Charles Hutton, of the Military Academy at Woolwich. Communicated by Samuel Horsley, LL.D. Sec. R. S. p. 50 IV. A new Case in Squinting, by Erasmus Darwin, M. D. F. R. S.; communicated by Thomas Astle, Esq. F. R. S. p. 86 V. A Cure of a Muscular Contraction, by Electricity. By Miles Partington, in a Letter to William Henly, F. R. S. p. 97 VI. An VI. An Account of a large Stone near Cape Town. In a Letter from Mr. Anderson to Sir John Pringle, Bart. P. R. S.; with a Letter from Sir William Hamilton, K. B. F. R. S. to Sir John Pringle, on having seen pieces of the said Stone. p. 102 VII. A Letter from Nathaniel Polhill, Esq. Member of Parliament for the Borough of Southwark, to Mr. John Belchier, F. R. S. on Mr. Debray's Improvements in the Culture of Bees. p. 107 VIII. An improved Method of tanning Leather. By David Macbride, M. D. communicated by Sir John Pringle, Bart. P. R. S. p. 111 IX. Observations on the Population and Diseases of Chester, in the Year 1774. By J. Haygarth, M. D. p. 131 X. An Account of some Electrical Experiments, by Mr. William Swift, in a Letter to John Glen King, D. D. F. R. S. p. 155 XI. An Account of the Island of Sumatra, &c. By Mr. Charles Miller. Communicated by Edward King, Esq. F. R. S. p. 160 XII. A Meteorological Diary, &c. kept at Fort St. George in the East Indies. By Mr. William Roxburgh, Assistant-surgeon to the Hospital at the said Fort. Communicated by Sir John Pringle, Bart. P. R. S. p. 180 XIII. Experiments upon Air, and the effects of different kinds of Effluvia upon it; made at York. By W. White, M. D. F. S. A. Communicated by John Fothergill, M. D. F. R. S. p. 194 XIV. An XIV. An Account of the Earthquake which was felt at Manchester and other Places, on the 14th Day of September, 1777. In a Letter from Mr. Thomas Henry, F. R. S. to William Watson, M. D. F. R. S. p. 221 XV. Sundry Papers relative to an Accident from Lightning at Purfleet, May 15, 1777. 232 XVI. On the Arithmetic of Impossible Quantities. By the Rev. John Playfair, A. M. Communicated by the Rev. Nevil Maskelyne, D. D. F. R. S. and Astronomer Royal. p. 318 XVII. Reflections on the Communication of Motion by Impact and Gravity. By the Rev. Isaac Milner, M. A. Fellow of Queen's College, Cambridge. Communicated by Anthony Shepherd, D. D. F. R. S. and Plumian Professor at Cambridge. p. 344 XVIII. Observations on the Limits of Algebraical Equations; and a general Demonstration of Des Cartes's Rule for finding their Number of affirmative and negative Roots. By the Rev. Isaac Milner, M. A. Fellow of Queen's College, Cambridge. Communicated by Anthony Shepherd, D. D. F. R. S. and Plumian Professor at Cambridge. p. 380 XIX. Journal of a Voyage to The East Indies, in the Ship Grenville, Capt. Burnet Abercrombie, in the Year 1775. By Alexander Dalrymple, Esq. F. R. S. Communicated by the Hon. Henry Cavendish, F. R. S. p. 389 XX. An Essay on Pyrometry and Areometry, and on Physical Measures in general. By John Andrew De Luc, F. R. S. p. 419 XXI. Extract of a Register of the Barometer, Thermometer, and Rain, at Lyndon, in Rutland. By Thomas Barker, Esq. Communicated by Sir John Pringle, Bart. P. R. S. p. 554 XXII. Journal of the Weather at Montreal. By Mr. Barr. Communicated by Richard Saunders, M. D. F. R. S. p. 557 XXIII. Extract of Meteorological Observations made at Hawkhill, near Edinburgh. By John M'Gouan, Communicated by Sir John Pringle, P. R. S. p. 562 XXIV. Extract of a Meteorological Journal for the Year 1777, kept at Bristol, by Samuel Farr, M. D. p. 567 XXV. Journal of the Quantity of Rain that fell at Holme, near Manchester, from 1765 to 1769; and at Barowby, near Leeds, from 1772 to 1777. By George Lloyd, Esq. F. R. S. p. 571 A Meteorological Journal kept at the House of the Royal Society, by Order of the President and Council. p. 573 PHILOSOPHICAL TRANSACTIONS, OF THE ROYAL SOCIETY OF LONDON. VOL. LXVIII. For the Year 1778. PART II. LONDON, PRINTED BY J. NICHOLS, SUCCESSOR TO MR. BOWYER; FOR LOCKYER DAVIS, PRINTER TO THE ROYAL SOCIETY. MDCCCLXXIX. CONTENTS OF VOL. LXVIII. PART II. XXVI. An Account of the Island of St. Miguel. By Mr. Francis Maffon, in a Letter to Mr. William Aiton, Botanical Gardener to His Majesty. Communicated by Joseph Banks, Esq. F. R. S. page 601 XXVII. An Account of a remarkable Imperfection of Sight. In a Letter from J. Scott to the Rev. Mr. Whisson, of Trinity College, Cambridge. Communicated by the Rev. Michael Lort, B. D. F. R. S. p. 611 XXVIII. An Account of Baptisms, Marriages, and Burials, during Forty Years, in the Parish of Blandford Forum, Dorset. Communicated by Richard Pulteney, M. D.: F. R. S. p. 615 XXIX. Part of a Letter from Matthew Guthrie, M. D. of Petersburg, to Dr. Priestley, F. R. S. on the Antiseptic Regimen of the Natives of Russia. p. 622 XXX. Astronomical Observations made in the Austrian Netherlands in the Years 1773, 1774, and 1775. By Nathaniel Pigott, Esq. F. R. S. Foreign Member of the Academies CONTENTS. Academies of Brufels and Caen, and Correspondent of the Royal Academy of Sciences at Paris. p. 637 XXXI. Observations on the Scurvy. By Charles De Mertans, M. D. Dated Vienna, Jan. 14, 1778. p. 661 XXXII. Comparison between Sir George Shuckburgh and Colonel Roy's Rules for the Measurement of Heights with the Barometer; in a Letter to Col. Roy, F. R. S. from Sir George Shuckburgh, Bart. F. R. S. p. 681 XXXIII. An Account of the Calculations made from the Survey and Measures taken at Schehallien, in order to ascertain the mean Density of the Earth. By Charles Hutton, Esq. F. R. S. p. 689 XXXIV. An Account of the Blue Shark, together with a Drawing of the same. By W. Watson, jun. M. D. F. R. S. p. 789 XXXV. A Description of the Exocetus Volitans, or Flying Fish. By Thomas Brown, Surgeon, near Glasgow. Communicated by Dr. Fothergill, F. R. S. p. 791 XXXVI. Reasons for dissenting from the Report of the Committee appointed to consider of Mr. Wilson's Experiments; including Remarks on some Experiments exhibited by Mr. Nairne. By Dr. Musgrave, F. R. S. p. 801 XXXVII. Experiments on Electricity, being an Attempt to shew the Advantage of elevated pointed Conductors. By Mr. Edward Nairne, F. R. S. p. 823 XXXVIII. On the Use of an Amalgam of Zinc, for the Purpose of electrical Excitation, &c. By Bryant Higgins, M. D. in a Letter to Richard Brocklesby, M. D. F. R. S. p. 861 XXXIX. XXXIX. Chemical Experiments and Observations on Lead Ore. By Richard Watson, D.D. F.R.S. in a Letter to Sir John Pringle, Bart. P.R.S. p. 863 XL. Description of a most effectual Method of securing Buildings against Fire, invented by Charles Lord Viscount Mahon, F.R.S. p. 884 XLI. A Method of finding, by the Help of Sir Isaac Newton's binomial Theorem, a near Value of the very slowly-converging infinite Series $x + \frac{x^2}{2} + \frac{x^3}{3} + \frac{x^4}{4} + \frac{x^5}{5} + \ldots$ when $x$ is very nearly equal to 1. By Francis Maseres, Esq. F.R.S. Curfitor Baron of the Exchequer. p. 895 XLII. A Method of extending Cardan's Rule for resolving one Case of a Cubick Equation of this Form, $x^3 - qx = r$, to the other Case of the same Equation, which it is not naturally fitted to solve, and which is therefore often called the irreducible Case. By Francis Maseres, Esq. F.R.S. Curfitor Baron of the Exchequer, p. 902 XLIII. Account of the Advantages of a newly-invented Machine much varied in its Effects, and very useful for determining the perfect Proportion between different Moveables acting by Levers and Wheel and Pinion. By Mr. Le Cerf, Watch-maker at Geneva; Communicated by Lord Viscount Mahon, F.R.S. p. 950 XLIV. New Experiments upon the Leyden Phial, respecting the Termination of Conductors. By Benjamin Wilson, Esq. F.R.S. p. 999 XLV. Observations on the Solar Eclipse which happened June 24, 1778. By Mr. William Wales, F.R.S. and Master of the Royal Mathematical School in Christ's Hospital. p. 1013 XLVI. XLVI. An Eclipse of the Sun June 24, 1778, observed at Leicester. By the Rev. Mr. Ludlam, Vicar of Norton, near Leicester; communicated by the Astronomer Royal. p. 1019 XLVII. A ready Way of lighting a Candle, by a very moderate Electrical Spark. By John Ingenhouzsz, M. D. F. R. S. p. 1022 XLVIII. Electrical Experiments, to explain how far the Phenomena of the Electrophorus may be accounted for by Dr. Franklin's Theory of positive and negative Electricity. By John Ingenhouzsz, M. D. F. R. S. p. 1027 XLIX. Observations and Experiments tending to confirm Dr. Ingenhouzsz's Theory of the Electrophorus; and to shew the Impermeability of Glass to Electric Fluid. By William Henly, F. R. S. p. 1049 L. Track of His Majesty's armed Brig Lion, from England to Davis's Streights and Labrador, with Observations for determining the Longitude by Sun and Moon and Error of common Reckoning; also the Variation of the Compass and Dip of the Needle, as observed during the said Voyage in 1776. By Lieutenant Richard Pickersgill, late Commander of the said Vessel; communicated by Nevil Maskelyne, D. D. F. R. S. and Astronomer Royal. p. 1057