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 advisable, 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. LXXVIII. PART I. I. Of the Methods of manifesting the Presence, and ascertaining the Quality, of small Quantities of Natural or Artificial Electricity. By Mr. Tiberius Cavallo, F. R. S. Page 1 II. The Croonian Lecture on Muscular Motion. By George For- dyce, M. D. F. R. S. p. 23 III. An Account of a Mass of native Iron, found in South-America. By Don Michael Rubin de Celis. Communicated by Sir Joseph Banks, Bart. P. R. S. p. 37 IV. Frigorific Experiments on the Mechanical ex- pansion of Air, explaining the Cause of the great Degree of Cold on the Summits of high Mountains, the sudden Condensa- tion of aerial Vapour, and of the perpetual Mutability of atmospheric Heat. By Erasmus Darwin, M. D. F. R. S.; com- municated by the Right Honourable Charles Greville, F. R. S. p. 43 V. Some Observations on the Heat of Wells and Springs in the Island of Jamaica, and on the Temperature of the Earth below the Surface in different Climates. By John Hunter, M. D. F. R. S.; communicated by the Hon. Henry Cavendish, F. R. S. p. 53 VI. A Table of the mean Heat of every Month for Ten Years in London, from 1763 to 1772 inclusively. By William Heberden, M. D. F. R. S. and A. S. p. 66 VII. On Centripetal Forces. By Edward Waring, M. D. F. R. S. Professor of Mathematics at Cambridge. p. 67 VIII. Experiments on local Heat. In a Letter from James Six, Esq. to the Rev. Francis Wollaston, LL.B. F. R. S. p. 103 IX. Observations on the Manner in which Glass is charged with the electric Fluid, and discharged. By Edward Whitaker Gray, M. D. F. R. S. p. 121 X. Experiments on the cooling of Water below its freezing Point. By Charles Blagden, M. D. Sec. R. S. and F. A. S. p. 125 XI. Experiments and Observations relating to the Principle of Acidity, the Composition of Water, and Phlogiston. By Joseph Priestley, LL.D. F. R. S. p. 147 XII. Some Observations on the Irritability of Vegetables. By James Edward Smith, M. D. F. R. S. p. 158 XIII. An Account of Experiments made by Mr. John McNab, at Albany Fort, Hudson’s Bay, relative to the Freezing of Nitrous and Vitriolic Acids. By Henry Cavendish, Esq. F. R. S. and A. S. p. 166 APPENDIX. Translation of Don Michael Rubin de Celis’s Letter to the Royal Society, relative to a Mass of native Iron, found in South-America. p. 183 A Meteorological Journal kept at the Apartments of the Royal Society, by Order of the President and Council. p. 191 THE PRESIDENT and COUNCIL of the ROYAL SOCIETY adjudged, for the Year 1787, the Medal on Sir Godfrey Copley's Donation, to JOHN HUNTER, Esq. F. R. S. for three Papers which were printed in the last Volume of the Philosophical Transactions. CONTENTS OF VOL. LXXVIII. PART II. XIV. OBSERVATIONS on the Natural History of the Cuckoo. By Mr. Edward Jenner. In a Letter to John Hunter, Esq. F. R. S. Page 219 XV. Of the Temperament of those musical Instruments, in which the Tones, Keys, or Frets, are fixed, as in the Harpsichord, Organ, Guitar, &c. By Mr. Tiberius Cavallo, F. R. S. p. 238 XVI. Description of a new Electrical Instrument capable of collecting together a diffused or little condensed Quantity of Electricity. By Mr. Tiberius Cavallo, F. R. S. p. 255 XVII. On the Conversion of a Mixture of dephlogisticated and phlogisticated Air into nitrous Acid, by the electric Spark. By Henry Cavendish, Esq. F. R. S. and A. S. p. 261 XVIII. Experiments on the Effect of various Substances in lowering the Point of Congelation in Water. By Charles Blagden, M. D. Sec. R. S. and F. A. S. p. 277 XIX. Additional Experiments and Observations relating to the Principle of Acidity, the Decomposition of Water, and Phlogiston. By Joseph Priestley, LL.D. F. R. S. With Letters to him on the Subject, by Dr. Withering, and James Keir, Esq. p. 313 XX. On the Probabilities of Survivorships between Two Persons of any given Ages, and the Method of determining the Values of Reversions depending on those Survivorships. By Mr. William XXI. An Account of a remarkable Transposition of the Viscera. By Matthew Baillie, M.D. In a Letter to John Hunter, Esq. F.R.S. p. 350 XXII. On the Georgian Planet and its Satellites. By William Herschel, LL.D. F.R.S. p. 364 XXIII. Experiments on the Formation of Volatile Alkali, and on the Affinities of the Phlogisticated and light Inflammable Airs. By William Austin, M.D. Fellow of the College of Physicians; communicated by Charles Blagden, M.D. Sec. R.S. p. 379 XXIV. Some Properties of the Sum of the Divisors of Numbers. By Edward Waring, M.D. F.R.S. p. 388 XXV. Experiments on the Production of artificial Cold. By Mr. Richard Walker, Apothecary to the Radcliffe Infirmary at Oxford. In a Letter to Henry Cavendish, Esq. F.R.S. and A.S. p. 395 XXVI. A Description of an Instrument which, by the turning of a Winch, produces the Two States of Electricity without Friction or Communication with the Earth. In a Letter from Mr. William Nicholson to Sir Joseph Banks, Bart. P.R.S. p. 403 XXVII. Abstract of a Register of the Barometer, Thermometer, and Rain at Lyndon in Rutland, with the Rain in Hampshire and Surrey, in 1787. Also some Account of the Annual Growth of Trees. By Thomas Barker, Esq. Communicated by Thomas White, Esq. F.R.S. p. 408 XXVIII. On the Era of the Mahometans, called the Hejera (هجرة), By William Marsden, Esq. F.R.S. and A.S. p. 414