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PRESENTS MADE TO THE ROYAL SOCIETY From November 1781 to July 1782; WITH The NAMES of the DONORS. Donors. Presents. 1781. Nov. 8. Acad. of Sciences at Paris. Histoire de l'Academie Royale des Sciences pour 1772, part II. 4° Acad. of Sciences at Berlin. Memoires de Mathematique et de Physique, tom. VIII. 4° Royal Acad. of Sciences at Stockholm. Nouveaux Memoires de l'Academie Roy. des Sciences et Belles Lettres pour 1778. 4° Mr. Hope. Transactions of the Royal Academy of Sciences at Stockholm for 1780 4° Augustus Broussonet, M.D. Torberni Bergman Opuscula Physica et Chemica, tom. II. 8° Mr. Tiberius Cavallo. The Second and Third Parts of the Nineteenth Volume of the Transactions of the Academy of Sciences at Haerlem. 8° Assemblee Publique de la Soc. Roy. des Sciences de Montpellier. 4° On the Nature and Properties of Air and other permanently elastic Fluids. 4° Donors Donors. 1781. Nov. 8. Mr. John Hunter. William Black, M. D. M. le Comte de la Cépede. L'Abbé Gerard de Soulavie. M. le Baron de Marivetz. Mr. Vandermonde. Caf. Gomez Ortega. Mr. Jeaurat. 15. Society of Antiquaries. Dec. 6. Mr. Phil. Hurlock. 13. Mr. Raper. Dean of Exeter. 1782. Jan. 10. The Margrave of Brandenburg Anspach. Prefects. A practical Treatise on the Diseases of the Teeth. 4° Medical and Political Observations on the Small Pox. 8° Essai sur l'Electricité, 2 vols. 8° Histoire Naturelle de la France Meridionale, 2 vols. 8° Physique du Monde, par M. le Baron de Marivetz et M. Gouffier, tom. II. 4° Systeme D'Harmonie applicable à l'Etat actuel de la Musique. 4° Instruccion sobre el Modo mas fugero y Economico de transportar Plantas vivas por mar y tierra á los países mas distantes. 4° Connoissance des Temps pour l'Année 1783. 8° Archæologia, vol. V. 4° A Print from an ancient Picture in Windsor Castle, together with a Description of the same, by John Topham, Esq. Commentarii de Rebus in Scientia Naturali et Medicina gestis, 6 vols. 8° A Meteorological Journal, kept at Canton in China, from July 1771 to Dec. 1774. 4° A MS. entitled, The Life of Confucius, being a translation from Chinese into Italian, by Louis Poviot. 8° Poems, supposed to have been written at Bristol in the XVth Century, by Thomas Rowley, Priest; with a Commentary, in which the Antiquity of them is considered and defended. 4° C. C Schmidel. Vorstellung einiger merkwürdigen Versteinerungen. 4° Icones Plantarum et Analytis Partium. fol. Conradi Gesneri Opera Botanica edidit C. C. Schmidel. fol. Fossilium Metalla et Res Metallicas concernentium Glebae suis coloribus expressæ. 4° Donors. Donors. 1782. Jan. 10. The Margrave of Brandenburg Anspach. Presents. Ad. Lud. Wirfing, Marmora et adfines aliqui Lapides coloribus suis expressae. 4° Petr. Sim. Pallas, Novae species Quadrupedum & glirium ordine. 4° C. I. Trew, Amoenissimorum Florum Imagines, edidit J. M. Seligman. fol. C. Nic. Jenty Demonstratio uteri pregnantis mulieris, cum foetu ad partum maturi. fol. I. C. D. Schreber. Abbildung der Saugthiere, 4 parts. 4° I. C. D. Schreber. Beschreibung der Graesser nebst ihren Abbildungen, part I. and II. fol. I. F. Charpentier. Mineralogische Geographie der Chursachischen Lande. 4° F. C. Gunther. Samlung Von Nefter und Eyerne verschiedener Vögel, part I. fol. I. F. Esper. Nachricht von neuentdeckten Zoolithen. fol. Beschaffigungen der Berlinischen gesellschaft Naturforschender Freunde, 4 parts. 8° Der Naturforscher, 14 parts. 8° Tables of the Product and Powers of Numbers, by Charles Hutton, LL.D., fol. Memoires sur les Observations Meteorologiques faites à Franeker en Frise l'Année 1779. 8° Reliquiae Houftounianae seu Plantarum in America Meridionali à Gul. Houston, M. D. R. S. collectarum Icones. 4° A Topographical Description of such Parts of North America as are contained in an annexed Map of the middle British Colonies in N. America. fol. Memoires de Chimie, tom. I. 8° Assemblee Publique de la Société des Sciences de Montpellier. 4° Two Chinese books; the one being an Account of the Island of Japan; the other, Maps of the late Conquests of the Chinese towards Thibet. fol. Board of Longitude. I. H. Van Swinden. Jan. 17. Sir Joseph Banks, Bart. Mar. 7. Thomas Pownall, Esq. Mr. I. A. Chaptal. Augustus Broussonet, M. D. Mr. Lance, Super-cargo at Canton. Donors. Donors. 1782. April 11. Sir William Hamilton. Francesco Grifelini. Mr. Thomas Henry. 25. M. De Cazeaux. Mr. Bemetzieder. Mr. Mesmer, Physician at Vienna. May 2. William Jones, Esq. The Anonymous Translator. Mr. G. Herbiniaux, Surgeon at Bruxelles. 9. Academy of Sciences at Brussels. 16. Gilbert Thompson, M. D. Royal Academy of Sciences at Paris. Mr. Jeaurat. Presents. A Supplement to the Campi Phlegræi, being an Account of the great Eruption of Mount Vesuvius, in August 1779. Lettere Odeporiche, tom. I. 4° Essays Physical and Chemical, by Mr. Lavoisier; translated from the French by Mr. Thomas Henry. fol. Essai sur l'Art de Cultiver la Canne et d'en extraire le Sucre. 8° Nouvel essai sur l'Harmonie. 8° Methode et Reflexions sur les Leçons de Musique. 8° Precis Historique des faits Relatifs au Magnetisme Animal, Six Copies. 8° Lettre d'un Medecin de la Faculté de Paris à un Medecin de Londres. Ouvrage dans lequel on prouve contre Mr. Mesmer que le Magnetisme Animal n'existe pas, Three Copies. 8° Observations sur le magnetisme Animal, par M. D'Eslon, Two Copies. fol. The Mahomedan Law of Succession to the Property of Intestates, in Arabic, with a verbal Translation and explanatory Notes, by William Jones, Esq. 4° The Inferno of Dante, translated into English. 4° Traité sur divers Accouchemens laborieux et sur les Polypes de la Matrice, 2 vols. 8° Memoires de l'Academie Imperiale et Royale des Sciences et Belles Lettres de Bruxelles, tom. II. et III. 4° Memoire sur les Maniere d'elever les Abeilles, par M. Zeghers. 4° Memoirs of the Life, and a View of the Character, of the late Dr. John Forthergill. 8° Memoires des savans étrangers pour les années 1777 et 1778. 4° Memoirs sur les Lunettes Diplantidiennes ou à double Image et sur les Objectifs et les Oculaires Achromatiques. 4° Donors. Donors. 1782. June 6, Charles Burney, M. D. 13. Dr. Block, of Berlin. Thomas Pennant, Esq. Francis Milman M. D. Nic. Charles Molitor. Mr. John Nichols. Presents. A general History of Music, from the earliest Ages to the present Period, vol. II. 4° Six Numbers of a new Natural History of Fishes, and a Dissertation on the Intestinal Worms. 4° A Journey from Chester to London. 4° An Enquiry into the Source from whence the Scurvy and putrid Fevers arise. 8° The miscellaneous Philosophical Writings of Dr. Ingen-houz, translated into German by Nicolas Charles Molitor. 8° Biographical and Literary Anecdotes of Mr. William Bowyer, Printer, F. A. S. and of many of his learned Friends. By John Nichols, his Apprentice, Partner, and Successor. 4° AN INDEX TO THE SEVENTY-SECOND VOLUME OF THE PHILOSOPHICAL TRANSACTIONS. A. ABERRATION of the fixed stars. See Velocity of the Rays of Light. Taken in its enlarged sense, depends on the relative velocities of light and of the telescope, p. 59. Acids. See Saline Substance, Inflammable Air. Aerial acid. See Fixed Air. André (Mr. William). See Monoculus Polyphemus. Angles. Two things necessary for measuring extremely small ones with accuracy, p. 82. Animal creation. See Vegetable Kingdom. Argillaceous bodies. Subject to a diminution of their bulk by fire, p. 308. Gage for measuring that diminution, p. 310. Attractive powers. See Saline Substances. Aurora Borealis. See Electricity. B. Barker, Thomas. See Rain. Barometer. See Rain. Bernoulli. See Thermometer. Bills of Mortality. See White, York. Their importance to the community, p. 35. Births and burials. See York. Black, Dr. See Phlogiston. Bradley, Dr. See Velocity of the Rays of Light, Fixed Stars. Part of a letter from him to Dr. Halley, on a new discovered motion of the fixed stars, p. 84. Brook, Abraham. See Electrometer. C. Calcareous earth. See Saline Substances. Canton, Mr. See Electricity. Cavendish, Lord Charles. See Thermometer. Collision of Bodies. Mr. Smeaton's new fundamental experiments upon, p. 337. Intended as a supplement to his tract on mechanic power, p. 338. Reason for now pursuing the same subject, ibid. The laws of collision are principally of three kinds, p. 338. Considerations on two bodies, equal in weight or quantity of matter, striking one another, p. 339. et seq. Description of the machine for collision, p. 347. For trials on elastic bodies, p. 349. For trials on non-elastic soft bodies, p. 350. Colours. See Fire. All eyes or lights are not equally adapted for distinguishing them, p. 308. Cornish porcelain clays. See Fire. Crellii, D. Laurentii. Nova experimenta chemica quae ad peniorem acidi e pinguedine eruti cognitionem valere videntur, p. 8—34. D. De la Lande. See Fixed Stars. Double stars. See Fixed Stars. Steps of vision preparatory to viewing double stars, p. 100. See Telescopes. Catalogue of double stars, by Mr. Herschel, p. 112. Introductory remarks, ibid. The general distribution of the subject, with terms used to express the comparative sizes, and observations on the colours of stars, ibid. p. 113. Some particular terms and contractions explained, p. 114. First class of double stars, p. 115. Second ditto, p. 122. Third ditto, p. 129. Fourth ditto, p. 136. Fifth ditto, p. 142. Sixth ditto, p. 150. Postscript, p. 157. Mr. Mayer, in his "De novis in caelo sidereo phænomenis," has given a pretty large list of double stars, some of them the same with those in Mr. Herschel's catalogue, ibid. Mr. Herschel's reason for using glasses with much higher powers than those used by Mr. Mayer, p. 158. Neither Mr. D. Mayer's instruments, nor his method, were adequate to his purpose, ibid. Difference between Mr. Mayer's calculation and Mr. Herschel's accounted for, p. 159. Reasons for using the expression double star in a few instances preferably to Comes, Companion, or Satellite, p. 161. Doubts. See Herschel. Earth of alum, or argillaceous earth. See Saline Substances. Electricity. Of the method of rendering very sensible the weakest natural or artificial electricity, by Mr. Alexander Volta, p. vii. [See the original Italian, p. 237.] Advantages of his electrophorus in investigating atmospherical electricity, ibid. Ordinary conductors are never entirely void of electricity, ibid. Description and management of the electrophorus, viii. et seq. When proper to use that apparatus, and when not, xi. Use and advantages of imperfect conductors, xii. Marble slabs or boards preferable to all other planes, for imperfect conductors, ibid. Not every sort of marble equally proper, xiii. Metal plates, by means of varnish, may be used instead of marble, ibid. Advantages of a varnished plate above the common electrophorus, xiv. Other planes may be substituted, with equal advantage, instead of marble or metal, ibid. Mr. Canton's assertion, that stronger signs of electricity may be obtained at the time of an aurora borealis than at any other, confirmed, p. xv. Better method than Mr. Cavallo's of discovering the electricity of certain bodies, p. xvii. The electric spark obtained from the evaporation of water, p. xviii. xxix. And from various effervescences, which produce inflammable, fixed, and nitrous airs, xix. The metal plate has a much greater capacity for holding electricity in one case than in others, ibid. The intensity of electricity must be inversely proportional to the capacity of the body electrified, p. xx. The capacity of conductors is not in proportion to the surface in general, but to the surfaces which are free, or uninfluenced by an homologous atmosphere, p. xxi. What the author means by a conjugate conductor explained, ibid. Various experiments in confirmation of the author's assertions, ibid. et seq. Why an electrified body parts with its electricity easier, and from a greater distance, when a pointed conductor than when a flat or globular one is presented to it, p. xxv. Usefulness of Mr. Cavallo's small or second condenser, p. xxviii. Electrometer. Account of a new one, by Mr. Abraham Brook, p. 384. Explanation of the plate, ibid. Method of making the divisions, p. 386. And of graduating the instrument, ibid. Its advantages above those in use, p. 387. Electrophorus. See Electricity. Equation. A new method of finding the equal roots of an equation by division. By the Rev. John Hellins, p. 417—425. Etna, Mount. See Rain. A slight earthquake there, preceded by a remarkable column of smoke, p. v. Eye-glass. See Optics. F. Fire. The force of it can only be justly ascertained by its effect on some known body, p. 307. Method of producing distinct colours and shades from calces of iron compounded with clay by different degrees of fire, ibid. The Cornish porcelain clays best for supporting the intensity and measuring the degrees of fire, p. 309. Method of preparing them for thermometric purposes, ibid. Fitzgerald, Keene. His experiments with Chinese hemp seed. See Hemp Seed. Fitzgerald, Mr. See Thermometer. Fixed air, or the aerial acid. Is capable of existing in two states, p. 195. Cannot be separated from any substance in a concrete state, and why, p. 196. See Electricity, Saline Substances, Sulphur. Fixed Stars. On the parallax of, by Mr. Herschel, p. 82. Difficulty of ascertaining the distance of the fixed stars, and from what causes, p. 82. See Angles. The noble method pointed out by Galileo, and first attempted by Hook, Flamsteed, Molineux, and Bradley, of taking distances of stars from the zenith that pass very near it, though it failed with regard to parallax, has been productive of the most noble discoveries of another nature, p. 84. Remarks upon Bradley's method of finding the parallax, p. 85, 86. De la Lande concludes that the question about parallax is resolved, and why, p. 85. Difficulties attending the method of zenith distances, p. 86. The method taken by Mr. Herschel to find the parallax, p. 87. See Telescopes. Which is free from every error the former is liable to, and by which the annual parallax, if it should not exceed the tenth part of a second, may still become visible, and be ascertained at least to a much greater degree of approximation than it ever has been done, p. 89, et seq. See Optics. High powers of magnifying absolutely necessary in the research of the parallax of the fixed stars, p. 95. Two different ways used by Mr. Herschel in settling the distances of double stars, p. 99. With his method of clasping them, p. 100, et seq. General postulata respecting the theory of the annual parallax of double stars, &c. p. 104, et seq. General observation on the time and place where the maxima of parallax will happen, p. 111. Flamstead. See Fixed Stars. G. Galileo. See Fixed Stars. Gioeni, Count de. See Rain. Gorshock, William. His register of the Parish of Holy Cross. See Holy Cross. Hamilton, H. Hamilton, Sir William. See Iron Works. Hearing, Account of the organ of, in fish, by John Hunter, Esq. p. 379. When Mr. Hunter first observed this organ, p. 380. Nothing more easy than the exposure of this organ of fish in general, ibid. Its description and situation in different fish, p. 381. et seq. Much more simple in fish than in the superior orders of animals, ibid. An experiment, shewing that sounds affect them much, p. 383. Heat. See Thermometer. Heckingham. See Lightning. Hellins, rev. John. See Equation. Hemp seed, Chinese. Surprising vegetation of some seeds sown two months after the proper season, p. 47. Description of the plants, ibid. Manner of preparing the plants for the production of hemp, ibid. Description of the plants when stripped, p. 48. Amazing weekly increase in length, ibid. Great advantages expected from the cultivation of this plant, through the patronage of the Society for the Encouragement of Arts, &c. ibid. Herzschel, William. A paper to obviate some doubts concerning the great magnifying powers used by him, p. 173. His present method of determining those powers, p. 175. His former method of determining those powers, ibid. Description of a camera-eye-piece, made for that operation, p. 176. Advantages and inconveniencies attending each method, ibid. See Fixed Stars, Double Stars, Lamp-Micrometer. Holy Cross, Salop. Extract of the register of the parish of, p. 53. An actual survey made in the year 1780, p. 54. Diseases and Casualties from 1770 to 1780, p. 55. Number of inhabitants actually surveyed every five years for thirty years, ibid. Reasons of the increase and decrease of the inhabitants in particular years, ibid. p. 56. An account of the marriages in this parish can be of no use in political arithmetic, and why, p. 56. And the public register is too general for such purposes, p. 57. Hook. See Fixed Stars. Hunter, John. See Hearing. I. Infinite series. A new method of investigating the sums of, by the rev. Samuel Vince, M. A. p. 389. Part I. containing a new and general method of finding the sum of those series which De Moivre has found in one or two particular cases; but whose method, although it be in appearance general, will, upon trial, be found absolutely impracticable, p. 390—401. Part II. containing the summation of certain series, the last difference of whose numerators become equal to nothing, p. 401—407. Part III. containing observations on a correction which is necessary in investigating the sums of certain series by collecting two terms into one, with its application to a variety of cases, p. 407—416. Inflammable air. See Phlogiston. The origin and nature of explained, p. 196—197. Is that very principle which alone is truly inflammable, as has been shewn by Mr. Volta, p. 197. Is also the principle which reduces metallic earths to a metallic state, and gives them their metallic splendour, p. 199. Is the substance which, with vitriolic acid, forms sulphur, p. 200. Acids cannot be the basis of inflammable air, and why, p. 202. Neither can earths or respirable air, p. 203. Different experiments on inflammable air, with observations, p. 204. et seq. The reason why inflammable air mixes so easily with water, and phlogiston, supposed to be the same substance, constantly repels, and is repelled by it, p. 209. Effects produced by Dr. Priestley, by melting the calces of iron, copper, lead, and tin, in inflammable air by means of a burning glass, p. 210. See Electricity. Ingen-houz, Dr. John. See Vegetable Kingdom. Inhabitants. Two methods of calculating the number of, in any place, where a numerical survey cannot be obtained, p. 39. Remarkable coincidence between those two measures, p. 40. Iron works. An account of some scoria from, which resemble the vitrified filaments described by Sir William Hamilton, p. 50. Filaments from Mount Vesuvius and the volcano in the Isle of Bourbon, described, ibid. See Slag, Smelting Houses. Sir William's opinion concerning the formation of those filaments, p. 51. K. King-crab. See Monoculus Polyphemus. Kirwan, Richard. See Saline Substances, Sulphur. Kraft, Mr. See Thermometer. L. Lamp-micrometer. Description of, and the method of using it, by Mr. William Herschel, p. 163. The natural imperfections of the parallel wire-micrometer, ibid. The lamp-micrometer, which is free from all those imperfections, and has the advantage of a very enlarged scale, described, p. 165. Its use, p. 167. Capable of great improvement by the application of wheels, pinions, &c., p. 168. The application of this instrument explained, p. 169. And exemplified, p. 170. The measures of this micrometer not confined to double stars only, but may be applied to any other objects that require the utmost accuracy, p. 177. Leibnitz, Leibnitz. Has attempted demonstrations of the law of refraction from principles very different from Sir Isaac Newton, p. 59. Lightning. Proceedings relative to the accident by, at Heckingham, p. 355. Letter from the Board of Ordnance to Sir Joseph Banks, P. R. S. ibid. Extracts from the minutes of the Council of the Royal Society, p. 356. Report of the Committee to the President and Council, p. 357. Description of the House of Industry at Heckingham, ibid. Dimensions of its principal parts, p. 359. Description of the conductors affixed to the chimneys, ibid. With their positions and respective terminations, p. 360. et seq. Time and manner of the lightning's setting fire to the building, p. 366. Its effect on different parts thereof, p. 367. et seq. Dimensions and description of the stable, p. 370. et seq. Three balls of fire observed to fall at the time of the accident, p. 377. The clouds at Norwich were negative on the day of the accident, ibid. Lloyd, George. See Rain. M. Magnesia, or muriatic earth. See Saline Substances. Magnifying. See Optics, Telescopes, Doubts. Marine acid air. See Saline Substances. Why it acts so feebly on oil, spirits of wine, &c. p. 236. Mayer, Mr. See Double Stars. Metallic Earths. See Inflammable earths. Meteorological Journal, p. 285. Micrometer, the parallel wire one. See Lamp micrometer. Mineral alkali. See Saline Substances. Mr. Turner, by a peculiar process, extracts it in the greatest purity from common salt, p. 188. Mineral substances. Analysis of two; viz. the Rowley-rag-stone and the Toad-stone, by William Withering, M. D. p. 327. Particulars concerning the conduct of the processes explained, p. 328. See Rowley-rag-stone, Toad-stone. Mobecau, Mons. His method of calculating the number of inhabitants in a place, without a numerical survey, p. 39. Molineux. See Fixed Stars. Monoculus Polyphemus (or King-crab) Linnæi. A microscopic description of the eyes of, by Mr. William André, Surgeon, p. 440. Has in reality four eyes, though they have been looked on as only two, ibid. Which are immoveable, p. 441. And consist of two small and two large ones, ibid. Description of the large ones, p. 442. And of the small ones, p. 443. Monstrous births. See Torlefs. More, Samuel. His account of some scoria from iron works, &c. p. 50. See Iron Works. Vol. LXXII. N. Newton, Sir Isaac. See Velocity of the Rays of Light, Leibnitz. Nitrous air. See Saline Substances, Electricity. Nollet, Abbé. His excellent method of discovering the errors occasioned by the inequalities on the inner surface of the glass of thermometers, p. 79. O Optics. Too much has hitherto been taken for granted in that science, p. 91. The position, "that we gain nothing by magnifying too much," considered, p. 92. et seq. Superiority of the single eye-glass to the double, in point of light and distinctness, p. 95. Optic pencil. Observations on, p. 96. P. Parallax of the fixed stars. See Fixed Stars. Perpetual motion. The idea of, a contradiction in terms, p. 354. Petit, Mr. See Sulphur. Phlogiston. See Saline Substances. The nature of it explained, p. 195. Can never be produced in a concrete state, single and uncombined with other substances, ibid. The causes of inflammable air and specific fire, which are different states of phlogiston, explained, according to the discoveries of Dr. Black, p. 196. See Fixed Air, Inflammable Air. Population. From Mr. Wales's "Inquiry into the present State of it in England and Wales," and different numbers of these Transactions, appears to be in a general and progressive state of improvement, p. 35. Precepts. List of, p. 445. Priestley, Dr. See Saline Substances. By his new analysis has produced the volatile alkali free from the aërial acid and water in the form of air, p. 191. See Inflammable air. R. Rain. Account of a new kind of rain at Mount Etna, by the Count de Gioeni, i. Various conjectures concerning the cause of, ibid. Methods of analysing it, to determine its origin, ii, iii. Which appears to be volcanic, iii. Not hurtful to animals or vegetables, iv. Its great extent accounted for, ibid. Table of the quantity of rain which fell near Barrowby near Leeds, by George Lloyd, Esq. p. 71. 71. Extract of a register of the barometer, thermometer, and rain, at Lyndon in Rutland, by Mr. Barker, p. 281. Refraction. Law of, explained, p. 58. Relazione di un a nuova pioggia, scritta dal Conte de Gioeni abitante della 3a reggione dell' Etna, p. 1. Rowley-rag-stone. See Mineral Substances. Where found, p. 329. Its more obvious properties, p. 330. Experiments on, ibid. Conclusions from those experiments, p. 332. Might probably be used advantageously as a flux for calcareous iron ores, p. 333. S. Saline Substances. Continuation of the experiments and observations on the specific gravity and attractive powers of various saline substances, by Mr. Kirwan, p. 179. Some mistakes in Mr. Kirwan's last paper rectified, ibid. Tables constructed in consequence thereof, p. 182. et seq. The quantity of pure acids taken up at the point of saturation, by mineral alkali, examined, p. 188. Ditto by the volatile alkali, according to the experiments of Dr. Priestley, p. 191. Ditto by calcareous earth, p. 192. Ditto by magnesia or muriatic earth, p. 193. Ditto by earth of alum or argillaceous earth, p. 194. Ditto by phlogiston, p. 195. Of the quantity of phlogiston in nitrous air, p. 211. Of the quantity of ditto in fixed air, p. 213. Nature and origin of fixed air examined, ibid. Various opinions concerning, and experiments made on, different kinds of air, p. 213—229. Mr. Kirwan's account thereof approved by Dr. Priestley, p. 230. Of the quantity of phlogiston in vitriolic air, p. 231. Method of pursuing that inquiry, ibid. Of the quantity of phlogiston in sulphur, p. 233. Of the quantity of ditto in marine acid air, p. 235. Table, shewing the solubility or insolubility of, in alcohol, by Dr. Withering, p. 336. Six, Mr. James. See Thermometer. Slag, or vitrified cinder. How produced, p. 51. Smeaton, John. See Collision of Bodies. Smelting houses. The large furnaces used there present a most striking resemblance of the eruption of a volcano, p. 51. Specific fire. See Phlogiston. Specific gravity. See Saline Substances. Showers of, thought by the ancients to have been miraculous rains, discovered to be volcanic, ii. Their being mixed with water accounted for, p. iv. Sulphur. See Inflammable Air, Saline Substances, Method of estimating the quantity of fixed air produced during its combustion, p. 233. All the attempts hitherto made to determine its constituent parts evidently defective, p. 234. Its specific gravity when weighed in water by Mr. Kirwan, and in oil by Mr. Petit, p. 235. Tables. See York, Holy Cross, Rain, Doubts, Saline Substances. Telescopes. Amazing improvements in the construction of, p. 89. Double start of excellent use in trying them, p. 101. Estimations made with one telescope cannot be applied to those made with another; nor can the estimations made with different powers of magnifying, though with the same telescope, be applied to each other, p. 102. Thermometer. Account of an improved one, by Mr. James Six, p. 72. Inconvenience attending the thermometers in common use, ibid. Which Van Swinden, Mr. Kraft, Lord Charles Cavendish, Mr. Fitzgerald, &c. have endeavoured to remedy, ibid. Description of Mr. Six's, p. 73. Which in some respects resembles those of Mr. Bernouilli and Lord Charles Cavendish; but differs in the essential property of shewing how high the mercury had risen in the observer's absence, p. 74. How that difference is effected, ibid. How to rectify this thermometer after an observation, without disturbing the mercury, p. 75. Method of depositing it, without hanging up, and of preventing the mercury shifting its place in the spirits within the tube, p. 76. And of making this thermometer a mercurial one, ibid. Other inconveniencies attending the common thermometers removed by this, p. 77. Mr. Six's different methods of constructing his thermometers, p. 78. Method of adjusting the divisions on the scale to the inequalities of the tubes, p. 78. See Nollet, Rain. An attempt to make one for measuring the higher degrees of heat, from a red heat up to the strongest that vessels made of clay can support, by Mr. Josiah Wedgwood, p. 305. Uses to which a measure for the higher degrees of heat may be applied, p. 306. Inconveniencies arising from the want of it, ibid. See Fire. Manner of constructing the thermometer, p. 308. Observations which occurred in using this thermometer, p. 311—322. Analysis of the clay of which the thermometric pieces are formed, p. 323—326. Toad-stone. See Mineral Substances. The mode of its stratification fully and accurately described, by Mr. Whitehurst, of Derbyshire, p. 333. Its more obvious properties, ibid. Experiments on, ibid. Conclusions from those experiments, p. 335. Torlise, John. His account of a monstrous birth in the East Indies, p. 44. Turner, Mr. See Mineral Alkali. Tweer. A term used in smelting iron, explained, p. 51. V. Van Swinden. See Thermometer. Vegetable kingdom. Some farther considerations on the influence of, on the animal creation, by John Ingen-housz, p. 426. Account of several experiments, demonstrating, that vegetables diffuse through our atmosphere, in the sun-shine, a conti- nual shower of beneficial truly vital air, ibid. p. 433. Observations thereon, p. 433—438. Benefits to be drawn from this new discovery, p. 438. Vegetation, uncommon. See Hemp Seed. Velocity of the rays of light. An experiment proposed for determining, by the aberration of the fixed stars, whether the rays of light, in pervading different media, change their velocity according to the laws which result from Sir Isaac Newton's ideas concerning the cause of refraction, and for ascertaining their velocity in every medium whose respective density is known, p. 58. See Leibnitz, Refraction. Proofs that the aberrations in a telescope filled with a dense fluid will precisely agree with that of Dr. Bradley's, only in the case of the rays moving swifter in the medium than in air, in the ratio assigned by Sir Isaac Newton, and that this same effect of aberration will itself be a proof of light being so accelerated within the telescope, p. 60. et seq. Propositions concerning the viewing a subject, when the dense fluid within the telescope is confined by object-glasses of any figure, p. 65. et seq. Vince, rev. Samuel. See Infinite Series. Vision. See Double Stars. Vitriolic acid. See Inflammable Air, Saline Substances. Volatile alkali. Saline Substances, Priestley. Volcanos. See Iron Works, Smelting Houses. Marine salt the basis, or one of the chief and most abundant menstrua, which excite the effervescence of, iv. The appearance of lightnings in their eruptions explained, xxxiii. Volta, Mr. See Inflammable Air, Electricity. W. Wales, Mr. See Population. Wedgwood, Josiah. See Thermometer. White, Dr. William. His observations on the bills of mortality at York, p. 35. See York. Wilson, Patrick. His proposed experiment by the aberration of the fixed stars, &c. See Velocity of the Rays of Light. Withering, Dr. William. See Mineral Substances, Saline Substances. Y. York. Observations on the bills of mortality at, p. 35. Table of the births and burials there from Aug. 5, 1728, to Aug. 5, 1735, p. 37. Of births and burials there from Jan. 1, 1770, to Dec. 1, 1776 inclusive, p. 38. Of births and burials there, with the proportion of males and females, annually, from January 1, 1770, to Dec. 31, 1776, p. 39. Of the mortality of the seasons there, ibid. Probable number of inhabitants in that city, p. 40. Decrease of the deaths there from 1735 to 1776, p. 41. The diseases there chiefly of the inflammatory kind, p. 42. Inoculation, the improved method of treating several disorders, and of managing infants, the general causes of the increasing population and healthiness there, ibid. The improvements in the streets, buildings, &c. have contributed to the salubrity as well as beauty of that city, p. 43. The number of plates in this volume is XVI.