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. I. The Croonian Lecture. On the Structure and Uses of the Membrana Tympani of the Ear. By Everard Home, Esq. F. R. S. page 1 II. On the Method of determining, from the real Probabilities of Life, the Values of Contingent Reversions in which three Lives are involved in the Survivorship. By William Morgan, Esq. F. R. S. p. 22 III. Abstract of a Register of the Barometer, Thermometer, and Rain, at Lyndon, in Rutland, for the Year 1798. By Thomas Barker, Esq. p. 46 IV. On the Power of penetrating into Space by Telescopes; with a comparative Determination of the Extent of that Power in natural Vision, and in Telescopes of various Sizes and Constructions; illustrated by select Observations. By William Herschel, LL.D. F. R. S. p. 49 V. A second Appendix to the improved Solution of a Problem in physical Astronomy, inserted in the Philosophical Transactions for the Year 1798, containing some further Remarks, and improved Formulae for computing the Coefficients A and B; by which the arithmetical Work is considerably shortened and facilitated. By the Rev. John Hellins, B. D. F. R. S. and Vicar of Potter’s Pury, in Northamptonshire. p. 86 VI. Account of a Peculiarity in the Distribution of the Arteries sent to the Limbs of slow-moving Animals; together with some other similar Facts. In a Letter from Mr. Anthony Carlisle, Surgeon, to John Symmons, Esq. F. R. S. p. 98 VII. Outlines of Experiments and Inquiries respecting Sound and Light. By Thomas Young, M. D. F. R. S. In a Letter to Edward Whitaker Gray, M. D. Sec. R. S. p. 106 VIII. Observations on the Effects which take place from the Destruction of the Membrana Tympani of the Ear. By Mr. Astley Cooper. In a Letter to Everard Home, Esq. F. R. S. by whom some Remarks are added. p. 151 IX. Experiments and Observations on the Light which is spontaneously emitted, with some Degree of Permanency, from various Bodies. By Nathaniel Hulme, M.D. F.R.S. and A.S. p. 161 X. Account of a Series of Experiments, undertaken with the View of decomposing the Muriatic Acid. By Mr. William Henry. Communicated by the Right Hon. Sir Joseph Banks, Bart. P. R. S. p. 188 XI. On a new fulminating Mercury. By Edward Howard, Esq. F. R. S. p. 204 APPENDIX. Meteorological Journal kept at the Apartments of the Royal Society, by Order of the President and Council. THE President and Council of the Royal Society adjudged, for the year 1799, the Medal on Sir Godfrey Copley's Donation, to the Rev. John Hellins, B.D. F.R.S. for his improved Solution of a Problem in physical Astronomy, &c. printed in the Philosophical Transactions for the year 1798, and his other mathematical papers. XII. On double Images caused by atmospherical Refraction. By William Hyde Wollaston, M. D. F. R. S. - p. 239 XIII. Investigation of the Powers of the prismatic Colours to heat and illuminate Objects; with Remarks, that prove the different Refrangibility of radiant Heat. To which is added, an Inquiry into the Method of viewing the Sun advantageously, with Telescopes of large Apertures and high magnifying Powers. By William Herschel, LL. D. F. R. S. - p. 255 XIV. Experiments on the Refrangibility of the invisible Rays of the Sun. By William Herschel, LL. D. F. R. S. - p. 284 XV. Experiments on the solar, and on the terrestrial Rays that occasion Heat; with a comparative View of the Laws to which Light and Heat, or rather the Rays which occasion them, are subject, in order to determine whether they are the same, or different. By William Herschel, LL. D. F. R. S. p. 293 XVI. Chemical Experiments on Zoophytes; with some Observations on the component Parts of Membrane. By Charles Hatchett, Esq. F. R. S. - p. 327 XVII. On the Electricity excited by the mere Contact of conducting Substances of different kinds. In a Letter from Mr. Alexander Volta, F. R. S. Professor of Natural Philosophy CONTENTS. in the University of Pavia, to the Rt. Hon. Sir Joseph Banks, Bart. K. B. P. R. S. - - - p. 403 XVIII. Some Observations on the Head of the Ornithorhynchus paradoxus. By Everard Home, Esq. F. R. S. - p. 432 CONTENTS. XIX. Experiments on the solar, and on the terrestrial Rays that occasion Heat; with a comparative View of the Laws to which Light and Heat, or rather the Rays which occasion them, are subject, in order to determine whether they are the same, or different. Part II. By William Herschel, LL.D. F.R.S. p. 437 XX. An Account of the Trigonometrical Survey, carried on in the Years 1797, 1798, and 1799, by Order of Marquis Cornwallis, Master-General of the Ordnance. By Captain William Mudge, of the Royal Artillery, F.R.S. Communicated by his Grace the Duke of Richmond, F.R.S. p. 539