University of California. Berkeley c^i£f&£^ /^ f^*£li ^^ i^0:kii^ j /^ "■p.|-2> ^^^^myftP r Sw. ^^^^^^K^' rai THE PHILOSOPHICAL TRANSACTIONS OF THE JRIOYAL SOCIETY OF LONDON, FROM THEIR COMMENCEMENT, IN 1665, TO THE YEAR 1800; WITH NOTES AND BIOGRAPHIC ILLUSTRATIONS, BY chari.es hutton, ll.d. f.r.s. george shaw, m.d. f r.s. f.l.s. richard pearson, m.d. f.s.a. VOL. X. FROM 1750 TO 1755. LONDON : PRINTED BY AND FOR C. AND R. BALDWIN, NEW BRTDGE-STREET, BLACK KR I »R> 1809. r/i /'^C4^d/, ILOAN STACK CONTENTS OF VOLUME TENTH. . WARD, Ancient Roman Inscri|iiion. . 1 Fa. Hallerstein, Astron. Observations at Pekin 'i J. Martyn, an Aurora Australis 3 Chr. Maire, Observations of Eclipses .... 4 J. Bartrani, Dragon-fly of Peiinsylvaiiia . . ibid Alb. Haller, Experiments on Respiration. . 5 Fa. Gaubil, Geography of the Chinese. ... 6' Apothecaries, Catalogue of 50 Plants .... 7 Dr. Miles, Green Mould on Firewood. ... 8 H. Baker, on small Plants and Seeds .... ibid M. Grischow, on a Solar Eclipse 9 Alb. Haller, the Course of the Semen. . . . ibid J. Martyn, an Aurora Borealis 12 Dr. Miles, an Aurora Borealis ibid Wm. Watson, Electrical Experiments .... ibid L. Euler, the Orbits of the Planets l6" Apothecaries, Catalogue of .50 Plants .... 18 J. Lock, Inundation near Keswick ibid Mr. Chalmers, Extraordinary Fireball .... !<) M. Nollet, on Italian Electricity 20 J. Barde, Fracture in the Arm 28 J. Bartrara, May-flies of Pennsylvania .... ibid Apothecaries, Catalogue of :' 0 Plants .... 29 Dr. Layard, Imposthume in the Stomach. . ibid Edw. Wright, Irregular Tide in the Forth. . 31 Jos. Warner, Tumour in the Bladder .... 32 Ld. Macklesfield, Solar and Lunar Cycles, the Epact, and on Easter 33 Biographical Notice of Earl Macklesfield. . ibid Dr. Starr, Morbus Strangulatorius 43 Dr. Hales, on the Purging Waters 48 J. Ward, on Boze on Medals 50 Rob. Mare, Travels through Italy 52 D. E. Baker, Account of a Dwarf 53 Rob. More, gathering Manna at Naples . . ibid Dr. Huxham, on the Northern Lights. ... 54 Dr. Starr, a Horse bitten by a Mad Dog . . ibid Job. Baster, of a monstrous Fetus 57 Dr. Pringle, Substances resist. Putref. 57, 73, 84 Biographical Notice of Sir John Pringle 57 J. Ward, Ancient Greek Inscription 62 H. Baker, on several Aurorae Boreales .... 6'3 Gowan Knight, on his Mariner's Compass. . 64 J. Smeaton, Improvements of the same . . 67 Biographical Notice of Mr. John Smeaton ibid Dr. Mortimer, on a curious Fish 70 Dr. Burton, Excrescence in the Womb. ... 71 J. Catlin and J. Short, a Lunar Eclipse . . 72 Jos. Piatt, curious Spheroidal Stone 77 Arth. Dobbs, Economy of Bees 78 J. Robertson, Log. Tang, and Merid. Line 89 Biographical Notice of Mr. John Robertson 89 G. M Bose, of a Lunar Eclipse 94 Dr. Miles, Heat of the Weather ibid Wm. Arderon, on the same subject ibid Dr. Bevis and J. Short, a Lunar Eclipse . . 95 J. EUicott, Height of Rockets' Ascent ... . g6 Wm. Watson, Platina, a New Semi-metal g7 Dr. Brownrigg, on the same 98 Dr. W. lleberden, a large Human Calculus 103 Biographical Notice of Dr. Wm. Heberden ibid Dr. Cha. Lytileton, Petrified Iiisect 105 voii. X. a IMve Dr. Mortimer, on the same subject 106" a curious Spheroidal Stone 107 various Accounts of Earthq. 10« Wm. Smith, of a Fire-ball in the Air 124 H. Baker, on the same 126 Dr. Sledman, Thermomet. Observations . . ibid The. Simpson, on Infinite Series 127 Dr. Bayly, Bark in the Small-pox 131 J. Canton, on Artificial Magnets ibid Biographical Notice of Mr John Canton. . ibid Peter Gabre, an Aurora Borealis 134 P. CoUinson, on the Cancer Major ibid Horace Walpole, his Di^ea.se of the Stone . 135 Biographical Notice of Horace Walpole . . ibid M. Nollet, on the Grotto de Cani 137 Rev. Patr. Murdocke, the Moon's Apogee. . 138 M. Herissant, Poison of Lamas & Ticunas 144 Tho. Deh)enham, Bones of a Fetu; extracted 153 Dr. Donati, Discoveries on Coral 154 Dr. Parson, on the Phocoe Marina: 161 Dr. de Castro, on an Iliac Passion l64 P. Wargentin, Magnetic Variation 1 65 Biographical Notice of Peter Wargentin . . ibid Mr. Freeman, Ruins of Herculaneum I66 Dr. Parsons, on Hermaphrodites 170 — — — on a very small Monkey .... 17 1 Antiquities found at Herculaneum 172 Dr. Bevi.s, Occultation of Venus 174 Ja. Short, curious Appearances in the Moon 1/5 Apothecaries, Catalogue of 50 Plants .... 176" Wm. Watson, on the Sex of Flowers .... ibid J. Harrison, a small Species of Wasps. ... 182 Dr. Cole, on Mr. Bright the Fat Man I84 Dr. Stedman, Etfects of White Henbane. . 185 Wm. Watson, Remarks on the same 186 Fra. Blake, Esq. on Steam-engine Cylinders 187 Biographical Notice of Francis Blake, Esq. ibid Ja. Short, Occultation of Venus I89 Wm. Watson, on Franklin's Electricity . . ibid Biographical Notice of Dr. Franklin ibid Capt. Ellis, on Hales's Ventilators ; also the "I'emperature and Saltness of the Sea. ... 195 Tho. Percival, on Roman Stations, Sec 197 Wm. Watson, on Winkler's Elect. Exper. ibid —— Bp. of London's Garden . . 200 Ph. C. Webb, of an inverted Iris 201 Dr. Huxham and Mr. Tripe, on a Body found in a Vault 202 L. Euler, Motion of the Moon's Apogee . . 203 Dr. Alston, on Lime-water, &c 204 M. le Cat, a New Trocart ibid M. GeofFroy, Vitrum Antimonii Ceratum. . 207 J. Browning, on a Dwarf 209 Rd. Dunthorne, on Comets ibid B. Franklin, Effects of Lightning 21^ M. le Cat, Excrescences of the Bladder .. 214 Wm. Watson, on the Cinnamon Tree. .. . 217 Dr. Cha. Morion, on Muscular Motion . . 219 Biographical Notice of Dr Charles Morton ibid R. Supple, Eruption of Vesuvius 220 J. Short, on a Lunar Eclipse ibid Fa. Hallerstein, Letter from China ibid M le Cat, Hernias with Sacks 221 Jos. Palmer, Effects of Lightning 223 Ja. Dodsoti, on Bills of Mortality ibid Biographical Notice of Mr. James Dodson ibid M. le Cat, Dissection of a Rupture 227 Wm. Watson, Medical Electricity ibid Ja. Short, on Serson's Horizontal Top 22^ Dr. T. Heberden, on the Pike of Teneriffe 230 , on the Weather in Madeira 232 W. Van IT:'zen, Quant, of Rain at Leyden 233 Tho. Percival, on a Double Child ibid Wm. Watson, on Electricity in Vacuo. . . . ibid Fa. Halle.stein, Astron. Observ. at Pekin . . 238 Dr. Mackenzie, Plague at Constantinople. . 239 Apothecaries, Catalogue of 50 Plants .... 242 Wm. Watson, on Medical Electricity ibid Jos. Warner, a Case of the Empyema .... 244 Eruption of Mount Vesuvius 245 Dr. Wilbraham, of an Hydrophoby ibid J. Smeato'.i, Improvement of the Air Pump 247 W. Watson, Aphyllon and Dentaiia Hepl. 250 Dr. Bond, Machine for striking Whales .. 251 J. Smeaton, on the Steam-engine 252 Dr. Parsons, on the Shells of Crabs 254 F. Blake, Splier. Trigon. reduced to Plane 255 M. Peyssonni'l, Treatise on Coral 257 Rd. Brooke, on Inoculation 268 Horace Walpole, his Case of the Stone . . 269 J. Parker, Eruption of Vesuvius 270 Jos. Warner, Stone in the Bladder ibid Rev. B. Ray, in a Water-spout 271 J. EUicott. Influ. of Heat & Cold on Clocks ibid J. Smeaton, New Tackle of Pulleys 278 Wm. Dixon, some Vegetable Balls 280 Rev. H. Kenroy, Copper Springs of Wicklow ibid Dr. Maty, Inoculation at Geneva 282 Biographical Notice of Dr. Maty ibid Dr. Parsons, on Corals, Corallines, &c. . . ibid Dr Mackenzie, Plague at Constantinople. . 283 J Short, Efi'ects of Heat & Cold on Clocks ibid Biographical Notice of John Harrison .... 284 Henry Eeles, on the Cause of Thunder . . 287 Dr. T. Hope, on Couching a Cataract .... ibid M. Mazcas, Analogy of Lightning and Elect. 289 M. Nollet, Electricity from the Clouds. . . . 295 M. Mylius, on the same subject 298 M. Faget, on the French Styptic ibid B. Franklin, the Electrical Kite 301 Wm. Watson, Exper. on Thunder Clouds 303 Mr. Brown, Inoculation at Salisbury ibid Dr. Henry, an extraordinary Wind ibid J. Short, on Frisi's Figure of the Earth 305 Rev. G. Costard, Eclipse foretold by Thales 310 Dr Hosiy, Ca.se of Bones softened, &c. . . 313 Fra. Drake, on a Roman Altar 3l6 Dr J. Ward, on the same Altar ibid Dr. J. Pringle, on the Jail Fever 318 Rev. Wm. Borlase, Islands of Scilly 324 Wm. Watson, making Sea-water Fresh . . 327 Sig. Paderni, Antiquities at Herculaneura. . 328 M. Clairaut, on Frisi's Figure of the Earth ibid Rev. Wm. Borlase, Storm of Thunder 335 Dr. Henry, Copper Springs at Wicklow . . 338 J. Robertson, Log. Lines on Gunter's Scale ibid CONTENTS. Page Vii^c John Dollond, Improvement of Telescopes 341 Biographical Notice of John Dollond .... ibid Wm. Watson, Therm. Observ. in Siberia, . 344 Apothecaries, Catalogue of 50 Plants .... 345 J. Ellis, Remarkable Coralline ibid Henry Baker, uncommon Fossils 347 Dr. Ward, on Boze's History of the Emperor Tetricus 349 Wm. Watson, on the Flora Siberica 351 P. Miller, Spondyl. Vulgare Hirsutum 355 Rev. G. Costard, on Zenophon's Eclipse . . 356 Sam. Sharp, Extraction of the Crystalline . . 357 Dr. Hume, Fish and Flesh pres. in Lime-wa. 358 J. Short, Invention of a new Micrometer. . ibid Serv. Savery, on his new Micrometer .... 359 J. Dollond, to Measure small Angles 364 J. Bond, Copper Springs at Wicklow .... 366 Dr. Bevis, Gascoigne Inventor of Microscope 369 J. Short, on the Transit of Mercury 370 Wm. Watson, on Nollet's Electricity .... 372 J. Browning, the Population of Bristol. . . . 379 Dr. Stukely, Eclipse predicted by Thales. . 380 Dr. Pocock, Giant's Causeway, Ireland 3S2, 383 Wm. Kersseboom, on Mortuary Tables . . ibid M. D'Incar\'ille, Observations on China. . . 387 T. Melville, Different refrangibility of Light 390 Mr. Short, Remarks on the same 393 Jos. Warner, Operation for the Empyema. . 394 Ja. Dodson, Inf. Series and Logarithms. . . 396 Dr. Lining, the Rain at Charlestown 40O Da Costa, on a Fossil found at Dudley. ... 401 Ja. Short, Euler's Theorem for Aberrations, ibid J. Dollond, on the same 402 Mr. Euler, on the same 403 Dr. Pringle, Softening, &c. of the Bones. . 406 Dr. Bevis and Ja. Short, Astron. Observats. 408 J. Ellis, a Cluster Polype, found at Greenland. 409 M. Gaubil, Observations at Pekin. ... 411, 412 Wm. Shervington, Transit of Mercury. .. 414 Ja. Simon, Weather Sec. at Dublin ibid Sam. Sharp, on Opening the Cornea ibid Dr. Ward, Roman Inscription at Bath 419 Benj. Wilson, Electrical Experiments. . . . 420 J. Canton, Electrical Experiments 421 M. Boss, on the vegetable Byssus 425 Wm. Watson, Remarks on the same ibid Ja. Short, Obs. on the Transit of Mercury. 426 Dr. R. Simson, on Converging Fractions. . 430 M. Mazeas, Electricity of the Air 434 Ja. Silvab'elle, Equinoxes, Nodes, &c 436 Geo. Costard, Age of Homer and Hesiod. . 440 Dr. T. Birch, on Nollet's Electricity 446 Biographical Notice of Dr. Thomas Birch. . ibid Rev. Jos. Spence, Herculaneum Antiquities 447 Ja. Dodson, Annuities and Survivorships. . 448 Geo. Edwards, Pennsylvania Pheasant. . . . 450 Biographical Notice of Mr. George Edwards, ibid J. Ellis, Particular Species of Coralline. . . 453 Wm. Arderon, on the Severe Cold Weather. 454 M. de L'Isle, Observations of the Planet Mars 455 J. Ferguson, on his Eclipsareon 456 Dr. Miles, on the Severe Cold Weather. . ibid Apothecaries, Catalogue of 50 Plants ibid J. Smeaton, to Measure a Sh4)'s Way. , , . ibid Page J. Chevalier, Eclipses observed at Lisbon. . 46"l J. Short, Observations on the same ibid J. Doliond, Instrument foi Small Angles. . Mi'i Da. E. Baker, Earthquake in Yorkshire. . . 40'9 John Landen, Properties of the Circle. . . . ibid Biographical Notice of Mr. John I.»-inden. . ibid Dr. Robert Watson, a Disease of the Skin. 475 Sam. Sharp, Agaric to Stop Bleedings. . . . 478 Jos. Warner, on the same subject. . . 479. 480 J. Smeaton, a New I'yrometer, &c 482 J. Martyn, on the Sex of Holly 486 Wm. Watson, on the same subject 487 Dr. T. Heberden, the Weather in Madeira. 488 Dr. Parsons, Archimedes" Burning Mirrors. . 488 Mr. Jacob. Elephants Bones in Sheppy I. . 4^;) J. Ellis, the Corallines on Oysters, &c. . . . 4i)() C. Paderni, Antiquities of Portici 4.')3 Wm. Lewis, Experiments on Platina 495 Biographical Notice of Mr. Wm. Lewis. . . ibid J. Swinton, on Palmyrene Inscriptions. . . . o'2'Z Dr. Lining, Electrical Kite Experiment. . . ibid Wm. Watson, Death of Professor Richman. 525 J. H. Winkler, Electrical Experiments. . . 529 Wm. Hirst, on a Fireball at Hornsey 530 M. Clairaut, Refrangibility of Light ibid J. Canton, Electrical Experiments 5 52 Dr. C. Hart, Medical Electricity 534 Dr. Brakenridge, Population of London. . . 535 Wm. Watson, Large Calculus in a Mare. . 541 Guitavus Brander, on the Belemnites .... 542 Wm. Watson, on Agaric, to stop Bleeding. .'-46" J. Warner, and B. Glooch, on the same .... ibid M. Bonnet, on Inoculation 548 Dr. Mackenzie, Earthq. at Constantinople, ibid C. Paderni, Discoveries at Herculaneum. . 549 Sir James Gray, on the same 551 Dr. Ste. Hales, to keep Water and Fish with Lime-water ibid Dr. Huxliam, Observations on Antimony. . 554 Wm. Watson, on Mr.Tull's Castrating Fi.sh. ibid W. Mountain & J. Dodson, Variation Chart. 556 Chr. Hce, on Moving Machines 558 Tho. Simpson, Isoperimetrical Problems. . . 56o Dr. Huxham, Effects of Lightning ibid Edw. Spry, Case of a Morbid Eye 56l H. Baker, on the Distempered Skin 562 Js. Jaraineau, Eruption of Vesuvius 563 Wm. Watson, Styptic Agaric Plant ibid Pe. Ascanius, Mountain of Iron Ore 564 Rd. Guy, Extraordinary Case of a Child. . . 565 Ja. Latterman, Agaric of Oak 566 La Fosse, Powder of Lycoperdon ibid Dr. Parsons, Lycoperdon Styptic ibid Dr. Miles, Thermometrical Observations. . ibid Dr. Oliver, Dropsy Cured by Sweet Oil. .. ibid J. Chevalier, Eclipses of Jupiter's Satellites. 567 M. Le Cat, Malignant Fevers at Rouen. . . ibid Death of Professor Richman of Petersburg. 574 Biographical Notice of Professor Richman. . 577 Dr. Ward, a Roman Inscription at Malton, ibid Apothecaries, Catalogue of 50 Plants 579 Tho. Simpson, Advantage of taking Means, ibid Ja. Ford, Agaric, &c to stop Bleedings. . ibid Ja. Porter, Remarks on Constantinople. , . 5S0 cont'ents. iii Page Tho. HoUis, Herculaneum Antiquitiea. . . . 584 On the same subject 58() Ja. Porter, Earthquakes at Constantinople. . .587 H. Eeles, Vapour, Wind, Weather, &:c. . ibid Dr. Parsons, on a Petrified Echinus 5.')4 M. Mazeas, on Toxicodendron ibid Ph. Miller, on the same C^G Dr Brakenridge, Probabilities of Life. . . . 598 Dr. Parsons, a Sheep with a Horn under the Throat 601 M. Daviel. Cancer of the Eye-lids, &c. . . 6"02 Dr. Ward, on four Roman Inscriptions. . . . 606 Israel Mauduit, American Wasps Nest. . . ()07 Magist. of Mascali, Eruption of Etna 6O8 Mr. Farrington, Chart-fish in Wales 609 J. Wathen to Restore Hearing ibid J. A. Schlosser, Action of Quicklime 6 12 J. Needham, part of the Intestines cut out. ibid Dr. Brocklesby, Sensibility and Irritability of some parts of Animals 61 3 Dr. Nicholls, Worms in Animal Bodies.. 616" Dr. T. Brady, on some Polype Insects. ... 61 7 Mr. Porter, Astron. and I'hys. Observations. 61 8 Dr. Fleming, the Fetus nourished by the Liquor A'nnii 61.V Wm. Thornhill, on Agaric to stop Blood , . 621 J. M. S. Barbosa, a Lunar Eclipse ibid Dr. Brakenridge, Population of England. . . ibid Dr. Ward, on two Roman Inscriptions. . . . 6'2i> Fr. Byam, Impression of a Fish in a Stone, and the Rain at Antigua 628 Arthur Pond, on the same Impression. . . . ibid G. Brander, Effects of Lightning 62Q Benj. Franklin, Electrical Experiments. . . . ibid , Electrical Observations. . . 6'32 W. Child, Effects of Lightning at Dorking. 634 Dr. Hales, Blowing Air through Distillations. ( 35 , on Ventilating Ships 641 , the same to cure lU-tasted Milk. 642 T. Barker, on the Comet expected in 175.S. 045 Biographical Notice of Thos. Barker, Esq. ibid Extraordinary Agitation of Waters, by J. Robertson, p. 647. By P. C. Webb, p. 647. By Dr. Adee, p. 649. By John Hodgson, p. 649. By W. Tempest, p. 649. By Dr. Pringle, p. 649. By Henry Mills, p. 650. By Dr. Birch, p. 6)0. By Mr. Thomlinson, p. 651. By R. Philips, p. 651. By Cap. Clarke, p. 651. By Dr. J. Blair, p 651. By Ld. Viscount Parker, p. 652. By Dr. Huxham, p. 652. By W. Borlase, p. 653. By Jos. Steplin, p. 655. By M.D. Hant, p. 655. By M. AUamand, p. 655. Rev. Mr. Bullock, the Earthquake Nov. I . 1755, in the Lead Mines Derbyshire. . . 656 Mr. Wolfall, the same Earthq. at Lisbon. . ibid Dr. J. M. Sacchetti, the same at Lisbon. . . 659 J. Latham, on the same at Lisbon ibid Mr. Stoqueler, the same at Lisbon 660 On the same Earthquake at Oporto 66 1 On the same at Madrid 662 Benj. Bewick, the same at Cadiz ibid Don Ant. d"Ulloa, the same at Cadiz ibid a 2 IV CONTENTS. (Jencial Fowke, the same in Barbary Dr. Tho. Heberden, the same at Madeira. . Cha. Chambers, the same at Madeira M. Trembley, Earthq. at Geneva, Dec. 9. J. Hyde, Earthq. at Boston, Nov. 18, 1755. C. Colden, the same at New York The same in Pennsylvania Dr. Alex. Russel, four Fishes at Aleppo. . . . Biographical Notice of Dr. Alex. Russel. . . Dr. J. A. Schlosser, Coral-like Substance. . J. Ellis, Remarks on the same Jos. Warner, Diseased Knee-joints Wm. Pye, Description of Manilla Dr. J. Wall, on the Malvern Waters Edw. Spry, on the Man who Swallowed Melted Lead at the Burning of Eddystone Lighthouse Dr. Huxham, on the same case Chr. Warwick, on Injecting Claret, &c. while Tapping C. Pade'ni, Antiquities at Herculaneum. . . Dr. R. Watson, Remarks on the same. . . . C. Paderni, on the same subject Dr. Whytt, Earthquake at Glasgow, &c. . . M. Bonnet, Earthquake in Swisserland . . . M. AUemand, Earthquake in Holland Tho. Pennant, CoroUoid Fossil Bodies Biographical Notice of Tho. Pennant, Esq. Sir Hans Sloane, Account of Inoculation. . Page Pag« 663 Sir Tho. Kilpatrick, Extra. Agitation of the 66+ Water in a Lake near Dumfries 692 665 Lord Anson, Irregularities of the Tides in 666 the Thames 695 ibid Rob. Dingley, on the same 694' 667 Dr. Brownrigg, on Dr. Hales's New Method ibid of Distillation ibid ibid Mrs. Belcher, Extra. Motion of the Waters ibid in the Lake Ontario 695 670 M. Grovestius, Earthquake in Holland 696 67 1 M. Allemand, on the same ibid ibid Dr. Pringle, Earthquakes at Brussels ibid 673 Edw. Matthews, Sinking of a River ibid ibid Dr. Pringle, Agitation of Waters in Scotland 69? Edw. Wright, Microscopical Observations 698 Dr. Hart, Paralytic Arm cured by Electr. . 700 ibid Dr. Peyssonnel, Observations in Guadaloupe 701 676 Sam. Warren, Earthquake at Dover, &c. . . 703 Abr. Trembley, Basaltes in Germany. . . . ibid ibid , Donati's Essay on the Natural 679 History of the Adriatic Sea 704 685 J. Swinton, on a Parthian Coin ^ 706 686 Apothecaries, Catalogue of .'^0 Plants ibid 687 Dr. Donati, Earthquakes at Turin 707 ibid Jesuits, Earthquakes at Brigue ibid ibid Condamine, Herculaneum Antiquities j 688 Structure of the Earth 709 ibid Dr. Peyssonnel, Currents of the Sea 710 ('90 Geo. Edwards, a kind of Crocodile 712 'JHE CONTENTS CLASSED UNDER GENERAL HEADS. Class I. Mathematics. 1 . Arithmetic, Annuities, Political Arithmetic. Annuities and Survivorship, Dodson 443 Population of London, Brakenridge 535 Advantd'ge of taking Means, Simpson .... 579 Probabilities of Life, Brakenridge 598 Population of England, Brakenridge 621 Bills of Mortality, Ja. Dodson 223 Log. Lines on Scales, J. Robertson 338 Population of Bristol, J. Browning 379 Mortuary Tables, Wm. Kersseboora 383 Infinite Series and Logarithms, Dodson . . 396 Converging Fractions, Dr. Simson 430 U. Algebra, Analysis, Fluxions. Infinite Series, Tho. Simpson. 127 Isoperimetrical Problems, Simpson 560 3. Geometry, Surveying, &c. Spherical Trigonometry reduced to Plane, Properties of the Circle, J. Landen 469 Fra Blake 255 Isoperimetrical Problems, Simpson 360 Class 11. Mechanical Philosophy. Dynamics. 203 Equinoxes, Nodes, &c. Silvabelle ." 436 305 Moving Machines, Chr. Hee 558 328 1. On the Moon's Apogee, L. Euler Figure of the Earth, J. Short On the same, by M. Clairaut 2. Astronomy, Astron. Observ. at Pekin, Fa. Hallerstein. . Observation of Eclipses, Chr. Maire A Solar Eclipse, M. Grischow Orbits of the Planets, L. Euler Solar and Lunar Cycles, Epact, Easter, &c. Ld. Macclesfield The Mariner's Compass, G. Knight On the same, by Mr. John Smeaton Chronology, Navigation. 2 A Lunar Eclipse, Catlin and Short 72 4 Log. Tang, and Merid. Line, Robertson . . 89 9 A Lunar Eclipse, G. M. Bose 94 16 Bevis and Short 95 Moon's Apogee, P. Murdocke 138 33 Occultation of Venus, Dr. Bevis 174 64 Curious Appearance of the Moon, Short . . 175 67 Occultation of Venus, J. Short 189 CONTENTS. Page The Moon's Apogee, L. Euler 203 On Comets, Richard Dunthorne 209 On a Lunar Echpse, J. Short 220 Observations in Gliina, Hallerstein ibid Horizontal Top, J. Short .' 229 Astron. Observ. at Pekin, ITallerslein .... 238 Eclipse predicted by Thales, Costard 310 Zeiiophon's Eclipse, G. Costard 356' Transit of Mercury, J. Short 370 Eclipse predicted by Thales, Stukely 380 Astron. Obser\'. Bevis and Short 408 Observations at Pekin, Gaubil +11,412 Transit of Mercury, Sher\ inton 414 On the same, by J. Short 426 3. Pneumatics. On the Air-pump, J. Smeaton 247 Elasticity of the Air, M. Mazeas 4. Optics, Alusic. Equinoxes, Nodes, &c. Silvabelle Age of Homer and Hesiod, Costard Observations on Mars, de L'Isle Eciipsareon, J. Ferguson Measuring a Ship's Way, Smeaton .... Eclipses at Lisbon, J. Chevalier Obsen'ations on the same, J. Short .... To take small Angles, J. Dollond Eclipses of Jupiter's Satellites, Chevalier , Advantage of Means, Simpson Astron. and Phys. Observ. Porter , A Lunar Eclipse, Barbosa Comet ex|)ected 1758, Tho. Barker . . . . , On the same Theorem, J. Dollond . . . On the same again, L. Euler Instrument for small Angles, Dollond . Archimedes' Burning Mirrors, Parsons. Refrangibility of Light, Clairaut Microscopical Observations, Wright. . . 5. Electricity, Magyietism, Pyrotecliny, Thermometry, &c. Improvement of Telescopes, Dollond .... 341 Measure of small Angles, Dollond 36"4 Gascoigne Inventor of Microscope, Bevis. . 369 Refrangibility of Light, T. Melville 390 Remarks on the same. J. Short 393 Euler's Theorem for Aberrations, Short . . 401 Electric.ll Experiments, Wm. Watson 12 Italian Electricity, M. NoUet 20 Mariner's Compass, Gowan Knight 64 Improvements of the same, J. Smeaton . . 67 Thermometer Observations, Stedman .... 126 Artifici.il Magnets, J. Canton 131 M.ignetic Variations, P Wargentin l65 On Franklin's Electricity, Wm. Watson . . 189 Winkler's Electrical Experiments, Watson 197 Effects of Lightning, B. Franklin 212 Medical Electricity, Wm. Watson 227, 242 Electricity in Vacuo, Wm. Watson 233 Analogy of Lightning and Electric. Mazeas 289 Electricity from the Clouds, M. NoUet 295 On the same subject, M. Mylius 298 The Electrical Kite, B. Franklin 301 Experiments on Thunder Clouds, Watson. . 303 Therm. Obser\'. in Siberia, Watson 344 On NoUet's Electricity, Watson 372 Electrical Experiments, B. Wilson ^ J. Canton Electricity of the Air, M. Mazeas On NoUet's Electricity, Dr. T. Birch . . New Pyrometer, &c. J. Smeaton Archimedes's Burning Mirrors, Parsons Electrical Kite Experiment, Dr. Lining. . , Death of Professor Richroan, Watson . . , Electrical Experiments, J. H. Winkler. . , , J. Canton Medical Electricity, Dr. C. Hart Variation Chart, Dodson and Mountain. . . . Effects of Lightning, Dr. Huxham Thermometer Observations, Dr. Miles. . . . Death of Professor Richman of Petersburg Effects of Lightning, G. Brander Electrical Observations, B. Franklin Paralytic Arm cured by Electricity, Hart. . Class III. Natural History. I. Zoology. 4 A small species of Wasp, J. Harrison . Cluster Polype at Greenland, J. Ellis . Pennsylvania Pheasant, Geo. Edwards . Charr-fish in Wales, Farrington Fishes at Aleppo, Dr. A. Russel A kind of Crocodile, Geo. Edwards . . , Dragon-fly of Pennsylvania, Bartram . . . Travels through Italy, Rob. More 52 A Curious Fish, Dr. Mortimer 70 The Cancer Major, P. CoUinson 134 Phoca: Marinae, Dr. Parsons 161 A very small Monkey, Dr. Parsons 171 2. Botany Catalogue of 50 Plants, Apothecaries, 7; 18; Vegetable Balls, Wm. Dixon 29; 176; 242; 345; 456; 579; 706. ~ ~ ~" "" '"" Of White Henbane, Dr. Stedman 185 Remarks on the same, Wm. Watson .... 186 Bp. of London's Garden, Wm. Watson . . 200 The Cinnamon Tree, Wm. Watson 2!7 Aphyllon and Dentaria Hept. Watson .... 250 The Flora Siberica, Wm. Watson Spondyl. Vulgare Hirsutum, Miller . . The Vegetable Byssus, M. Bose . . . . Remarks on the same, Wm. Watson The Sex of Holly, J. Marty n On the same subject, Wm. Watson. . Page 436 440 455 456 ibid 461 ibid 462 567 579 6I8 621 645 434 402 403 462 488 530 698 420 421 434 446 482 488 522 525 529 532 534 556 560 566 574 629 632 700 182 409 450 609 6Gr 712 280 351 355 425 ibid 486' 487 VI CONTENTS. Curious Spheroidal Stone, Jos. Piatt Platina, a new Semi-metal, Wra. Watson On the same, Dr. Brownrigg Petrified Insect, Dr. Cha. Lyttleton On the same. Dr. Mortimer Curious Spheroidal Stone, Mortimer Discoveries on Coral, Donati Treatise on Coral, Peyssonnel Copper Springs of Wicklow, Kenroy Corals, Corallines, &c. Dr. Parsons. ... . Copper Springs of Wicklow, Dr. Henry . Remarkable Coralline, J. Ellis Uncommon Fossils, Henry Baker Copper Springs of Wicklow, J. Bond . . . Giants' Causeway in Ireland, Dr. Pocock 382 Mineralogy. Page Pase 77 A Fossil found at Dudley, Da Costa 401 97 A Species of Coralline, J. Ellis 453 98 Elepluint's Bones in Sheppy Isle, Ellis .... 489 105 On the Belemnites, G. Brander 542 106' Mountain of Iron Ore, P. Ascanius 564 107 A Petrified Echinus, Dr. Parsons 594 154 On Toxicodendron, M. Mazeas ibid 257 On the same. Ph. Miller 596" 280 Impression of a Fish on a Stone, Byam . . 6'28 282 On the same, Arthur Pond 628 338 A Coral-like Substance, Schlosser 670 345 Remarks on the same, J. Ellis 671 347 Coralloid Fossil Bodies, T. Pennant 688 366 Basaltes in Germany, Trembley 703 , 383 Adriatic Natural History, Trembley 704 4. Geography and Topography Chinese Geography, Fa Gaubil 6 Oporto Earthquake Keswick Inundation, J. Lock 18 Earthquakes in various places, Mortimer . . 108 The Grotto de Cani, M. NoUet 137 Vesuvius Eniption, R. Supple 220 Pike of Teneriffe, Dr. T. Heberden 230 Eruption of Mount Vesuvius 245 On the same, J. Parker 270 Figure of the Earth, Ja Short 305 Scilly Islands, Wni. Borlase 324 Figure of the Earth, M. Clairaut 328 Giants' Causeway in Ireland, Pocock, 382, 383 Observations on China, D'lncarville 387 Observations at Pekin, Gaubil 411,412 Earthquake in Yorkshire, H. Baker 469 Weather, &c. in Madeira, Dr. T Heberden 488 Sheppy Isle, Elephant's Bones, Jacob .... 489 Constantinople Earthquake, Mackenzie . . 548 Vesuvius Eruption, Jamineau 563 Constantinople Remarks, Porter 580 ■ Earthquakes, Ja. Porter . . 587 Etna Eruption, Magistrates of Mascali . . . 6O8 Madrid Earthquake Cadiz Earthquake, Bewick, &c Barbary ditto, Fowke Madeira ditto, Heberden, &c 664 Geneva ditto, Trembley Boston ditto, J. Hyde New-York ditto, Colden Pennsylvania ditto Manilla, Description of, Wm. P)'e Glasgow Earthquake, Dr. Whytt Dumfries, Motion of Waters, Kilpatrick . . Holland ICarthquakes, AUemand, &c Brussels ditto. Dr. Pringle Sinking of a River, Matthews Scotland, Motion of the Waters, Pringle. . Guadaloupe Observation*, Peyssonnel Dover, &c. Earthquake, Warren Germany Basaltes, Trembley Adriatic Natural History, Trembley Turin Earthquakes, Donati Brigue ditto. College of Jesuits Herculaneum Antiquities, Condamine .... Structure of the Earth, Condamine Derbyshire Earthquakes, Bullock 656 Lisbon Earthquakes, Wolfall 656 On the same, by Latham, &c 659, 660 5. Hydrology. Irregular Tides in the Forth, Wright 31 Robertson, &c. 647, 649, 650, 651, 652, To Sweeten Sea-water, Wm. Wat'ion 327 653, 655, 673, 692, 693, 694, 695, 697, Extraordinary Agitation in the Waters, by 710. Class IV. Chemical Philosophy. 661 662 662 6«3 665 6(i(i ibid 667 ibid 673 687 692 696 ibid ibid G97 701 703 ibid 704 707 ibid 709 ibid On Purging Waters, Dr Putrefaction, &c. Dr. Pringle 57, 7S, 84 Poison of Lamas and Ticunas, Herissant. . 144 Sweetening Sea-water, Wra. Watson .... 327 Lime-water preserves Flesh, &c. Hume . . 358 On the same, by Dr. Hales 551 J . Chemistry. Hales 48 On Antimony, Dr. Huxham 554 Action of Quicklime, Schlosser b'jo Ventilating Distillations, Hales 635 ■ Ships and Milk, Hales 641, 642 Malvern Waters, Dr. Wall 673 Aurora Borealis, J. Martyn, Dr. Miles, 3, 12 Fireball, Mr. Chalmers 19 Aurora Borealis, Dr. Huxham, H. Baker, 54, 6'3 Heat of the Weather, Dr. Miles, W Arderon, 94 Various Earthquakes, Mortimer 108 Dr. Hales's Distillation, Brownrigg 694 2. Meteorology. Fireball in the Air, Wm. Smith 124 ( )n the same, Henr)' Baker 126 .Aurora Borealis, P. Gabre 134 All Inverted Iris, Ph. C. Webb 2OI Elfects of Lightning, Franklin, Jos P.ilmer 2 1 2,223 Westher in Madeira, Heberden The Rain ;U Leyden, Van Hazen A Waterspout, B. Ray Cause of Ihunder, Hen. Eeles Lightning and Electricity, Mazeas Electricity in the Clouds, Nollet. Mylins.2y5, The Electrical Kite, Frnnklin Thundi.'r-clouds, VVai Wiitsou Extraordinary Wind, Dr. 1 lenry Thunder-storm, Win. Borlase CONTENTS. Vll Pa^e Fagt 238 Rain at Charlestown, Dr. Lining 400 233 Weather, Sc. at Dublin, J. Simon 41+ 27 1 Severe coldWeatlier, Arderon, Dr. Miles, 454,5+6' 2S7 Electrical Kite, Dr. Lining 522 289 Death of Professor Richman, Watson .... 525 2.9'> Fire-ball at Hornsey, Wm. Hurst 530 301 Effects of Lightning, Dr. Huxham 560 303 Vapour, Wind, Weather, &c. Eeles 587 ibid Eftects of Lightning, G. Brander 6"29 335 at Dorking, Wm. Child 6'34 On Respiration, Haller 5 Course of the Semen, Haller 9 May-flies of Pennsylvania, Bartram 28 Alorbus Strangulatorius, Dr. Starr 43 Of a Dwarf. D. E. Baker 53 A Monstrous Fetus, Job Baster 57 Econoniv of Bees, A. Dobbs 78 On the Cancer Major, P. Gabre 134 On Hermaphrodites, Dr. Parsons 170 Mr. Bright the Fat Man, Dr. Cole 184 A Corpse found in a Vault, Huxham .... 202 Class f\ Physiology. 1. Physiolog!/ of Animals. On a Dwarf, J. Browning 209 Muscular Motion, Dr. Morton 219 A Double Child, Tho. Percival 233 Shells of Crabs, Dr. Parsons 254 Corallines on Oysters, &c. Ellis 490 TuH's Castrating Fish, Wm. Watson 554 A Sheep with a Horn under its Throat .... 6'01 Sensibility and Irritability, Brock 6"l3 Worms in Animal. Bodies, NichoUs 6\6 Polype-Insects, Dr. Brady 6l7 Fetus nour. by the Liq. Amnii, Dr. Fleming 619 1. Physiology of Plants. Green Mould on Fire-wood, Dr. Miles. ... 8 Vegetable Balls, Wm. Dixon 280 Small Plant? and Seeds, H. Baker 8 The Sex of Holly, J. Martyn, W.Watson 486,487 Manna at Naples, R. More 53 American Wasps' Nest, Mauduit 007 3. Medicine. On Purging Waters, Dr. Hales 48 A Horse bitten by a Mad Dog, Starr ... 54 Bark in the Small-pox, Dr. Bayly 131 Disease of the Stone, Walpole' 135, 26'9 Poison of Lamas and Ticunas, Herissant . . 144 Effects of White Henbane, Dr. Stedman . . 185 Remarks on the same, Wm. Watson .... 1 86 Lime-water, &c. Dr. Alston 204 Fracture in the Arm, J. Barde 28 Imposthume in the Stomach, Layard .... 29 Tumor in the Bladder, Warner 32 Excrescence in the Womb, Dr. Burton . . 71 A I/arge Human Calculus, Dr. Heberden . . 103 Disease of the Stone, Walpole 135 Bones of a Fetus Extracted, Debenham . . 1 53 The Iliac Passion, De Castro l64 A New Trocart, Le Cat 204 Excrescences of the Bladder, Le Cat 214 Hernias with Sacks, Le Cat 221 Dissection of a Rupture, Le Cat 227 Case of the Empyema, Warner 244 On Inoculation, Rd. Brooke 268 Case of the Stone, Walpole 269 Stone in the Bladder, Jos. Warner 278 Inoculation at Geneva, Dr. Maty 282 Couching a Cataract, Dr. Hope 287 On the French Styptic, M. Paget 298 Inoculation at Salisbury, Brown 303 The Bones Softened, &c. Dr. Hosty 313 Extracting the Crystalline, S. Sharp 357 Operation for the Empyema, Warner .... 39 1. The Bones Softened, &c. Dr. Pringle .... 406 Plague at Constantinople, Mackenzie 239, 283 A Hydrophoby, Dr. Wilbraham 245 Case of Softened Bones, &c. Dr. Hosty .. 313 The Jail-fever, Dr. Pringle 318 Disease of the Skin, Dr. R. Watson 475 Medical Electricity, Dr. Hart 534 Malignant Fevers at Rouen, Le Cat 567 Paralysis cured by Electricity, Dr. Hart . . 70O Surgery. Opening the Cornea, S. Sharp 414 A Disease of the Skin, Dr. R. Watson .... 475 Agaric to stop Bleedings, S. Sharp 478 On the same, J. Warner 479, 480 Large Calculus in a Mare, Watson 541 Agaric to stop Bleeding, Wm. Watson . . 546 On the same, Warner and Gooch 546 Inoculation, Bonnet 543 Of a Morbid Eye, Edw. Spry 561 The Distempered Skin, H. Baker 562 Styptic Agaric Plant, Wm. Watson 563 Extraordinary Case of a Child, Gay 565 Agaric of Oak, J. Latterraan ^QQ Lycoperdon Styptic, \ja Fosse, Parsons .... 566 Agaric Styptics, 8fc. Ja. Ford 579 Cancer of the Eye-lids, &c. Daviel 602 To restore Hearing, J. Wathen 609 Intestines cut, J. Needham 612 Agaric Styptic, Wm. Thornhill 621 Diseased Knee-joints, Jos. Warner 67 1 The Man that swallowed Melted Lead, Spry 673 On the same Case, Dr. Huxham djd Injections while Tapping, Warwick 676 Account of Inoculation, Sir Hans Sloane , , 69O Till CONTENTS, Class VI. The Arts. 1 . Mechanical. Pajic Hige Clocks affected by Heat and Cold, Short . . 283 A New Micrometer, Ja. Short 358 , Serv. Savory 359 Ascent of Rockets, J. Ellicott 96' Steam-Engine Cylinders, Fra. Blake 187 Hales's Ventilators, Capt. Ellis 1 95 Machine to strike Whales, Dr. Bond .... 251 The Steam-Engine, J. Smeaton 252 Clocks affected by Heat and Cold, EUicot 27 1 New Tackle of Pulleys, J. Smeaton 278 2. Chemical. Action of Rockets, Ellicott g6 Vitrum Antimonii Ceratum, Geoffroy 3. Antiquities. To measure Small Angles, Dollond SG* Gascoigne, Inventor of Micros. Bevis .... 36'9 To measure a Sliip's Way, Smeaton 456 Small Angles, Dollond 462 207 A Roman Inscription, Dr. Ward 1 Boze on Medals, Dr. Ward 50 Greek Inscription, Dr. Ward 62 Herculaneum Ruins, Freeman 166 Antiquities 172 Roman Stations, &c. Tho. Percival 1 97 A Roman Altar, Fra. Drake & Dr. J. Ward 3 16 Herculaneum Antiquities, PadernI 328 The Emperor Tetricus, Dr. Ward 349 Inscriptions at Bath, Dr. Ward 419 Age of Homer and Hesiod, Costard 440 Herculaneum Antiquities, Spence 447 Class VII. Biography ; Page Page 693 Dollond, John 341 187 Edwards, Geo. ... 450 446 Franklin, B 189 Portici Antiquities, Padenii +93 Palmyrene Inscriptions, Swiuton 522 Herculaneum Antiquities, Sir James Gray 551 Roman Inscription at Malta, Ward 577 Herculaneum Antiquities, T. Hollis 584 On the same Subject 586 Roman Inscriptions, Ward 606, 626 Herculaneum Antiquities, Paderni . . 549, 679 Remarks on the same. Dr. R. Watson .... 685 On the same Subject, Paderni 686 A Parthian Coin, J. Swinton 706 Anson, Ld. , Blake, Fra. . . . Birch, Dr. Tho. Barker, Tho. . . Canton, John . . Dodson, Jas. . . . 645 Heberden, Dr. W. 103 131 Harrison, John .. 284 223 Landen, John 469 Herculaneum Antiquities, Condamine or. Account of Authors. Page Lewis, Wm 495 Robertson. John. . Macclesfield Ld. 33 Ricbman Morton.Dr.Cha. 219 Russel, Alex.. Maty, Dr 282 Smeaton, John . . Pringle, Sir J. . 57 Walpole, Hor. . . Pennant, Tho. . 688 Wargentin, P 709 Page 89 577 6&1 67 135 163 REFERENCES TO THE PLATES IN VOLUME X. Plate I,Fig.I,p. 11; 11,12; III, IV, V, VI, 70; VII,V1II,51; IX to XIV, 105; XV to XVIII, 106; XIX to XXII. 107. p. 108. I, 126, II, III, 132; IV, V, VI, 133; VII, 134; VIII, 138; IX, X, 140; XI, XII, XIII, 164. I to XVIII, 154 to 160. Letter A to r, 159. I, 188; II, 204; III, IV, V, 205; VI to X, 217; XI, 253; XII to XIV, 256; XV, 296. I to IV, 272; V, 379. I, 307 ; II, 350; III, VI, 347; VII, 360 ; VIII, 401. Letter a to c .346. 1,359; 11,360; IlltoV, 361; VI, VII, 362; VIII, 364; IX, 437; X, XI, 483. Letter a to n, 41 1 Letter a to k, 453. I, II, 473; III, IV, 474; V, 526; VI, 528; VII, 529; VIII. 530, IX, 558; X, 628; I to VII, 491. p. 52 Z. I, II, 532; III, IV, 533; V to XVI, 545. XV, .. I to VII, 617; VIII to X, 644; XI to XIV, 668. XVI, . . Letter a to d, 67 1; fig. I to XII, 688 ; XIII, 699; XIV, 712. II, .. III, .. IV, .. V, .. VI, .. VII, . . vm, ., IX, .. X, , . XI, .. XII, ., XIII, . XIV, Errata.— Page 51, line 34, for fig. 3, 4, read fig. 7,8; 1. 3:., for fig. 10, read fig. 7 ; p. 106, 1. 1 1, for fig, 9, read 15 ; p. 180,1. 10, for pi. fl, r.pl. 5,1.27, for fig. H, r. fig. b, 1. 37, for fig. d, r. fig. n: p. 348, 1. 11, fr. bot. for fig. 1,2, r. fig. 3, 4 ; p. 359, 1. 5, fr- bot. for pi. lo read pi. 9; p. 401,1. 14, for fig. 8, pi. 9, read fig. 8, pi. 8; p. 522,1. 25, for pi. 14, read pi. )8. THE PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON; ABRIDGED, Remarks by Mr. John fVard, F. R. S. on an Ancient Roman Inscription, in the Possession of Richard Rawlinson, LL. D., F. R. S. found in that part of Italy which formerly belonged to the Sabines. N° 494, p. 293. This inscription is cut in a small brass plate. Tlie words of the inscription, as they stand on the plate, with some account how and where it was found, were formerly published by Fabretti. They are as follow: FLORAE •ti plavtivs drosvs MAG II V. S. L. M. The plate, and the inscription on it, so exactly agree with this account of Fa- bretti, as to leave no doubt of their being the same with those described by him. The present possessor of the plate purchased it at Rome, in Jan. 1720, n. s. At which time a small brass label was fixed to it, containing the following words cut in capital letters, ex regiis Christina thesavris. The words of the inscription may be read at length, with the proper supple- ments, in the following manner: Florae Tiberius Plautius Drosus, pagi magister anni secundi, votum solvit libens merito. The goddess Flora was thought by the Romans to preside over fields and trees, and therefore they addressed to her to favour them with prosperous and fruitful seasons. It appears from passages of Varro, referred to by Fabretti, that she was first a Sabine deity, and introduced at Rome by king Tatius in the time of Romulus, many ages before the institution of the Floralia. For that festival was not observed till the year of the city 513, when the expence of it was ordered VOL. x. B '2 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. to be paid out of the fines levied on those persons, who had converted the public lands to their own use, for feeding their cattle. Ti, the two first letters of the prenomen of the person mentioned in the in- scription, are the usual abbreviation of Tiberius; as a single t is of Titus. plavtivs, which follows, denotes the family name, and often occurs in Ro- man writers, as also on coins, where it is sometimes written Plotius, and at other times Plutius. DROSvs, the cognomen, he does not remember to have seen so spelt elsewhere, but he doubts not of its being the same as Drusus, which is frequently met with. For thus, as was just now observed, his family name is written three several ways, Plautius, Plotius, and Plutius. MAG. II. according to the explication given above, are an abbreviation of the words magister secundi, which stand for pagi magister anni secundi, was the whole to be expressed at length. The word pagus signifies a division or large portion of land, not much unlike what we call a shire or county. That the characters n. stand for anni secundi, the date of the time, during which this Drosus had then held that office, is confirmed by several inscriptions published by Gruter. In one of which we have mag. anni. v; in another MAGisTRi. anni. VI; and in two others mag. anni. primi, where the word denoting the time is expressed at length. As these different ways therefore of expressing the time relate to persons, who all bore that title, though not the same office, as appears by the inscriptions, they plaij;ily show in what sense those characters are to be taken here. The concluding letters v. s. l. m. which stand for votum solvit libens merito, contain the usual form of dedicating votive monuments. But the thing dedicated is not mentioned here, which was most probably a statue or an altar ; and probably the latter, from the number of such inscriptions in Gruter, and other collectors of ancient monuments, taken from altars. Observations of the Comet seen at Pekin in 1 748. jilso of an Occultation of Mars by the Moon, Dec. 6, 1747 ; and a Conjunction of Mars and f^eniis in March 1748; also a Conjunction of Jupiter and Venus Jan. 1, 1748. By the Rev. Father ^ug. Hallerstein. N° 494, p. 305. From the Latin. April "26, 1748, about 3 in the morning, this comet was first seen from the observatory at Pekin, in China; when the place of it was rudely taken, viz. in 18° of ^, with 27° north lat. Its head was equal to a star of the 3d order, and the tail about 1° long. Other observations, when the weather was favourable, were as follow. April 27, 2'' morn... 21° 10'^ long 31° 35'n lat. 28, 2 25 15 36 0 29} 2 29 10 40 O VOL. XLVI.] l-HILOSOPHICAL TRANSACTIONS. 3 The comet was seen several times after, till the 18th of June; chiefly among several unknown small stars ; but in its progress it passed just by the star y in Cepheus. Dec. 6, 1747, vvas an occultation of the planet Mars by the moon; viz. at 5*" 34™ 34* true time, Mars entered under the moon's obscure limb, and wholly disappeared. At 6*^ 46™ 2' the planet emerged from under the moon. March 15, 1748, at 6** 28", Mars and Venus were observed, in exact con- junction, almost touching, being nearly equal both in longitude and latitude. Jan. f, 1748, was observed a conjunction of Jupiter and Venus. At S'' 15™ 4P their distance was 1° 3' 49", Venus being 50' 35" more south, and 2™ 52' of time more west than Jupiter. An Observation of the Comet oflTAS, and some other Astronomical Observations made at Pekin. By Father Antony Gaubil. From the Latin. N° 494, p. 31 6. These observations nearly agree with those of F. Hallerstein preceding. From June 2 to 7 J the right ascension of the comet increased 6° and some minutes, and the declination decreased 55'. In the conjunction of Mars and Venus 1748, March 15*^ S*" 10"", he observed the distance of the western limbs of the planets to be J ' 29". Some eclipses of Jupiter's satellites were observed as below ; viz. True Time. Oct. 13<* g^ 40™ 30* Emersion of the 3d satellite. Ditto of the 1st. Total immersion of the 3d. Emersion of the 2d, doubtful. First emersion of the 2d, Nov. 7 8 52 59 First emersion of the 1st. Of an Aurora Aiistralis, seen Jan. 23, 1749-50, at Chelsea. By John Marty n, F.R.S. N°494, p. 319. Jan. 23, 1749-50, about half after 5 in the evening, looking to the s.s.w., Mr. M. thought he saw a reddish light about the planet Venus, which then shone exceedingly bright. Being suspicious of some fire in the neighbourhood, he went immediately to a window on the stair-case, where he saw a reddish light, which shone with such exceeding brightness, that the lustre of the fine constella- tion of Orion was almost effaced. He then went to a window facing the n.n.e. where he presently saw a very broad band of crimson light, like that which he observed from the same window, March 18, 1738-9; an account of which is printed in the Phil. Trans. N°46l. But in the former the red band was bounded on the north by streams of a greenish blue ; whereas the band now observed B 2 13 sextile or leap years, as they would otherwise have been; and consequently omitting the intercalary days, which, according to the Julian account, should have been inserted in the month of February in those years. But at the same time they ordered that every 400th year, consisting of a number of entire hun- dreds, divisible by 4, such as 1600, 2000, 2400, 2800, &c. should still be considered as bissextile or leap years, and of consequence that one day should be intercalated as usual in those years. This correction however did not entirely remove the error: for the equinoxes and solstices still anticipate l'' 53™ 20' in every 400 Gregorian years. But that difference is so inconsiderable as not to amount to 24 hours, or to one whole day, in less than 5082 Gregorian years. Of the Lunar Year, Cycle of IQ Years, and the Epact. — The space of time * This nobleman had been a pupil of the celebrated Wm. Jones, Esq. vice-president of the Royal Society, who was father of the no less celebrated Sir Wm. Jones, chief judge in India. Earl M. was elected president of the Royal Society about the year 1751, on the resignation of Martin Folkes, Esq. His lordship was greatly instrumental in procuring the introduction of the New or Gregorian stile into use in this country, which took place in 1752. And he died ia the year 1764 . VOL. X. F 34 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. between one mean conjunction of the moon with the sun and the next following, or a mean Synodical month, is equal to 29'' 12^ 44" 3' 2* 56', according to Mr. Pound's tables of mean conjunctions. The common lunar year consists of 12 such months. The intercalary or embolimaean year consists of 13 such months. In each cycle of 19 lunar years, there are 12 common, and 7 intercalary or em- bolimaean years, making together 235 synodical months. It was thought, at the time of the general council of Nice, which was holden in the year of our Lord 325, that IQ Julian solar years were exactly equal to such a cycle of IQ lunar years, or to 235 synodical months ; and therefore that at the end of IQ years, the new moons or conjunctions would happen exactly at the same times as they did 1 9 years before: and on this supposition it was, that some time afterwards, the several numbers of that cycle, commonly called the golden numbers, were prefixed to all those days in the calendar, on which the new moons then happened in the respective years corresponding to those num^ bers ; it being imagined, that whenever any of those numbers should for the future be the golden number of the year, the new moons would invariably happen on those days in the several months, to which that number was prefixed. But this was a mistake : For 19 Julian solar years contain 6939"* 18*' O™ 0» O* Whereas 235 synodical months contain only 6939 16 31 56 30 And are therefore less than I9 Julian solar years by O 1 28 3 30 This difference amounts to a whole day very nearly in 310.7 years, the new moons anticipating, or falling earlier, by 24 hours in that space of time, than they did before: and therefore now in the year 1750, the new moons happen above 4-^ days sooner, than the times pointed out by the golden numbers in the calendar. In order therefore to preserve a sort of regular correspondence between the solar and the lunar years, and to make the golden numbers, prefixed to the days of the month, useful for determining the times of the new moons, it would be necessary, when once those golden numbers should have been prefixed to the proper days, to make them anticipate a day at the end of every 310.7 years, as the moons will actually have done ; that is to set them back one day, by prefixing each of them to the day preceding that against which they before stood. But as such a rule would neither be so easily comprehended or retained in me- mory, as if the alteration was to be made at the end or at the beginning of com- plete centuries of years ; the rule would be much more fit for practice, and keep sufficiently near to the truth, if those numbers should be set back 9 days in the space of 2800 years ; by setting them back one day, first at the end of 400 years, and then at the end of every 300 years for 8 times successively : by which they would be set back, in the whole, 9 days in 2800 years. After which they must YOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 35 again be set one day back at the end of 400 years, and so on, as in the preceding 2800 years. By which means the golden numbers would always point out the mean times of the new moons, within a day of the truth. It is plain however that the lunar year will have lost one diiy more than ordi- nary, with respect to the solar year, whenever the new moons shall have antici- pated a whole day ; as they will have done at those times, when it is necessarj' that the golden numbers should, by the rule just now given, be set back one day : and consequently the epact, for that and the succeeding years, must ex- ceed by an unit the several corresponding epacts of the preceding 1 Q years. For the epact is the difference, in whole days, between the common Julian solar and the lunar year ; the former being reckoned to consist of 365, and the latter of only 354 days. If therefore the solar and the lunar year at any time should commence on the same day, the solar would, at the end of the year, have exceeded the lunar by 1 1 days ; which number 1 1 would be the epact of the next year : 22 would be the epact of the year following, and 33 the epact of the year after that, the epacts increasing yearly by 1 1 . But as often as this yearly addition makes the epact exceed 30, those 30 are rejected as making an intercalary month, and only the excess of the epact above 30 is accounted the true epact for that year. Thus when the epact would amount to 31, 32, 33, 34, &c. the 30 is rejectetl, and the epact becomes 1, 2, 3, 4, &c. Since therefore the lunar year will have lost a day more than ordinary, in re- spect of the solar year, whenever it is necessary to set the golden numbers one day back, as before observed ; it follows, that the epact must at the same time be increased by a unit more than usual ; the difference between the solar and the lunar year having been just so much greater than usual. That is, 12 must be added, instead of 1 1 , to the epact of the preceding, in order to form what will be the epact of the then present year. Which addition of a unit extraordinary to one epact, will occasion all the subsequent epacts (which will follow each other in the usual manner, each exceeding the foregoing by U) to be greater by 1, than their respectively corresponding epacts of the preceding IQ years. If therefore, instead of the golden numbers, the epacts of the several years were prefixed, in the. manner the Gregorians have done, to the days of the ca- lendar, in order to denote the days on which the new moons fall in those years of which those numbers are the epacts ; there would never be occasion to shift the places of those epacts in the calendar ; since the augmentation by 1 extraor- dinary of the epacts themselves would answer the purpose, and keep all tolerably right. Thus in a very easy method may the course of the new moons be pointed out, either by the golden numbers, or by the epacts, according to the Julian account or manner of adjusting the year, which goes on regular and uniform without any variation. t2 36 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. But the regulating these things for those who use the Gregorian account, is an affair of more intricacy ; and for them it will require more consideration to determine, when the epacts are to be more than ordinarily augmented, and at what, times they are to continue in their usual course ; nay, to know when they are not only not to be extraordinarily augmented, but also when they are to be diminished by a unit, by increasing one of them by 10 only instead of 11 as usual : and this happens much oftener with the Gregorians, than the increasing one of them by 12 instead of 1 1. For in every Gregorian solar year, whose date consists of any number of entire hundreds not divisible by 4, it is supposed that the equinox has anticipated one whole day ; and therefore 1 day, that which ought to be the intercalary one, is omitted ; and consequently the preceding solar year, where one day was lost, exceeded the lunar year by lO days only, instead of 1 1 . In order therefore to adapt the before-mentioned rule to the Gregorian ac- count, and to know in what years the epacts should either be extraordinarily augmented or diminished, and the golden numbers should either be set back- wards or forwards in the calendar ; the following rules and directions must be observed. First, that in the years 1800, 2100, 2700, 3000, &c. where the number of entire hundreds is divisible by 3, but not by 4, the Gregorian solar, as well as the lunar year, will have lost a day ; and consequently the difference between them will be the same as usual : therefore in those years there must be no alter- ation, either in the epacts or the golden numbers ; but the former must go on in the same manner, and the latter stand prefixed to the same days in the calen- dar, for another, as they did for the last 100 years. 2dly. The like will happen in the years 2000, 2800, 3200, &c. where the number of entire hundreds is divisible by 4, but not by 3 : for neither the Gre- gorian solar nor the lunar year is to be altered ; and therefore the epacts must go on, and the golden numbers stand, as they did before. But 3dly, in the years 2400, and 36oo, whose number of entire hundreds is divisible both by 3 and 4, the Gregorian solar year goes on as usual, and the lunar year has lost a day. The difference therefore between them being 12, the epact of the preceding year must be augmented by that number instead of 11, in order to form the epact of the then present year; by which a new set of epacts will be introduced, exceeding their precedent corresponding epacts by 1 : and the golden numbers must be set 1 day back in the calendar. 4thly and lastly, in the years IQOO, 2200, 2300, 2500, &c. where the num- ber of hundreds is divisible neither by 3 nor 4 ; the Gregorian solar. year having lost one day, and the lunar none, the difference between them being only 1 o ; VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 37 that number only, and not 11, is to be added to the epact of the preceding, to form the epact of that, the then present year , by which a new set of epacts will be introduced, all less by one than their precedent corresponding epacts : and the golden numbers nmst be set a day forwarder in the calendar ; that is, be prefixed to the day following that against which they stood in the precedent hun- dred years. This method would preserve a sort of regularity between the solar and the lunar years ; and, by means of the rules and directions before mentioned, the days of the new moons might be pointed out, either by the golden numbers or by the epacts, placed in the calendar for that purpose ; according to the Julian account for ever, and according to the Gregorian account till the year 4199 in- clusive, after which there must be some little variation made in the 4 last precepts or rules; but it would be to little purpose now, to attempt the framing of a new set of rules for so distant a time. The Gregorians have chosen to make use of the epacts to determine the days of the new moons, and follow pretty nearly the niles prescribed above ; except that they order the epacts to have an additional augmentation of a unit 8 times in 2500 years, beginning with the year 1 800, as at the end of 400 years ; to which 400 years if there be added 3 times 700, or 2100 years, the period of 2500 years will be completed in the year 3Q00. After which they do not make their extra- ordinary augmentation of a unit in the epacts, till at the end of another term of 400 years ; which defers that augmentation from the year 4200 to the year 4300. And this is the reason that the rules above delivered will require a vari- ation in the year 4200 ; whereas it is directed in this paper that the epacts should be augmented, or (which is the same thing) the golden numbers be set back in the calendar Q times in 2800 years. This arises from the Gregorians supposing, that the difference between 19 solar and as many lunar years, would not amount to a whole day in less than 312^ years ; whereas it has appeared above, that it would amount to a whole day in 310.7 years. But though the rule prescribed in this paper comes much nearer the truth, yet the error in either case is very in- considerable, being so small as not to amount to a whole day in many thousand years; and therefore is not worth regarding. Of fading Easter. — From what has been said, a method may be obtained for fixing, with sufficient exactness, the time of the celebration of the feast of Easter, which is governed by the vernal equinox, and by the age of the moon nearest to it. The former of which, when once rightly adjusted, may, (by the corrections mentioned in that part of this paper which relates to the solar year) be made to continue to fall at very near the same time with, or at most not to differ a whole day from the true equinox : and the same rules and directions which, as before shown, would without any great error, point out the times of the first day of the 38 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. moon, would with equal certainty point out the 14th, 15th, or any other: and thus the times of the oppositions, or the full moons, might be as well marked out, as those of the conjunctions or the new moons. The method now used in England, for finding the 14th day of the moon, or the ecclesiastical full moon, on which Easter depends, is by process of time be- come considerably erroneous : as the golden numbers, which were placed in the calendar to point out the days on which the new moons fall in those years of which they are respectively the golden numbers, now stand several days later in the same than those new moons really happen. Which error, as before ob- served, arises from the anticipation of the moons since the time of the council of Nice: and as the vernal equinox has also anticipated 11 days since that time; neither that equinox, nor the new moons, now happen on those days on which the church of England supposes them so to happen. When pope Gregory the 13th reformed the Julian solar year, he also made a correction as to the time of celebrating the feast of Easter, by placing the epacts (which he directed to be used for the future instead of the golden numbers) much nearer to the true times of the new moons, than the golden numbers then stood in the old calendar : he says, much nearer to the true times ; because in fact the epacts, as placed by him, were not prefixed to the exact days on which the new moons then truly fell. And this was done with design, and for a reason which it is not material to the purpose of this paper to mention. But the church of England, and that of Rome or the Gregorians, still agree in this ; that both of them mark (the former by the golden numbers, and the latter by the epacts corresponding to them) the days on which their ecclesiastical new moons are supposed to happen: and that 14 th day of the moon inclusive, or that full moon, which falls upon, or next after, the 1 1 st day of March, is the Paschal limit or full moon to both : and the Sunday next following that limit, or fiill moon, is by both churches celebrated as Easter-day. But the 21st of March being reckoned, according to the Gregorian account or the new style, 1 1 days sooner than by the Julian account or the old style, which is still in use among us ; and their ecclesiastical new moons being 3 days earlier than those of the church of England; it happens that though the church of England and that of Rome often do, yet more frequently they do not, celebrate the feast of Easter on the same natural day. It might however be easier for both, and could occasion no inconvenience, now that almanacs, which tell the exact times of the new moons, are in most people's hands; if all the golden numbers and epacts now prefixed to those days of the calendar, in our book of Common Prayer, and in the Roman breviary, on which the respective ecclesiastical new moons happen, were omitted in the places where they now stand; and were set only against those I4th days of the moon. TOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. SQ or those full moons, which happen between the 2 1st day of March and the 18th of April, both inclusive. Since no 14th day or full moon, which happens before the 21st of March, or after the 18th day of April, can have any share in fixing the time of Easter. By which means the trouble of counting to the 14th day, and the mistakes which sometimes arise from it, would be avoided. We do as yet in England follow the Julian account or the old style in the civil year; as also the old method of finding those moons on which Easter depends, both of which have been shown to be very erroneous. If therefore this nation should ever judge it proper to correct the civil year, and to make it conformable to that of the Gregorians, it would surely be advise- able to correct the time of the celebration of the feast of Easter also, and to bring it to the same day on which it is kept and solemnized by the inhabitants of the greatest part of Europe, that is, by those who follow the Gregorian ac- count. For though their method of finding the time of Easter is not quite ex act, but is liable to some errors: yet all other practicable methods of doing it would be so too; and if they were more free from error, they would probably be more intricate, and harder to be understood by numbers of people, than the method of determining that feast either by a cycle of epacts, as is practised by the Gregorians, or by that of IQ years or the golden numbers, in the manner proposed in the following part of this paper: and it is of no small importance, that a matter of so general a concern, as the method of finding Easter is, should be within the reach of the generality of mankind, at least as far as the nature of the thing will admit. For which reason, in case the legislature of this country should, before the year IQOO, think fit to make our civil year correspond with that of the Grego- rians, and also to celebrate all the future feasts of Easter on the same days on which they celebrate them; this last particular might be easily effected, without altering the rule of the church of England for the finding of that feast; and this only by advancing the golden numbers, prefixed to certain days in the calendar, 8 days forwarder for the new moons, or 21 days forwarder for the 14th days or full moons, than they now stand in our calendar. In order to explain this, it must be observed, that the Gregorian account, or the new style, is 1 1 days forwarder than the Julian account or the old style, which we still make use of; that is, the last day of any of our months, is the nth day of their next succeeding month. If therefore their ecclesiastical new moons fell on the same days with those of the church of England, the golden number 14, which now stands against the last day of February in our, that is the Julian calendar, should, when we should have adopted the Gregorian calendar be prefixed to the 1 1th day of March. But since their ecclesiastical new moons happen 3 days earlier than our ecclesiastical new moons at present do; so much 40 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. should be deducted from those 1 1 days, by which the golden numbers ought otherwise to be advanced; and the golden number 14 should not be placed against the 11th, but the 8th day of March; which being reckoned the first day of the moon, if we count on to the 14th day of the same inclusive, that would be found to fall on the 21st day of March; on which day the Gregorian paschal limit or full moon will happen, when the golden number is 14. And the like course should be taken with the rest of the IQ golden numbers ; which ought to be placed 8 days forwarder than they now stand, if they are to point out the new moon; or 21 days forwarder than they are at present, if they are to mark the 14th day of the moon, or the full moon ; the latter of which, as has been shown, would be more eligible, than to prefix those numbers to the days on which the new moons happen. Thus may the rule and method now used in the church of England, be most easily adapted to show the time of Easter, as it is observed by the Gregorians, till the year IQOO; at which time, and at the other proper succeeding times, if the golden numbers in the calendar shall either be advanced or set backward a day, according to the foregoing rules and directions for that purpose, they will continue to show the new or the full moons of the church of Rome, or the Gre- gorian calendar, with great exactness, till the year 4199: when, as has been already mentioned, there must be a little variation made in those rules and direc- tions. There is however one exception to those general rules and directions, which will be taken notice of in the next paragraph. On these principles is framed the table accompanying this paper, and showing, by means of the golden numbers, all the Gregorian paschal limits or full moons, from the reformation of the calendar, &c. by pope Gregory, to the year 41 99 inclusive. Which space of time is there divided into 1 6 unequal portions or periods; at the beginning of each of which, all the golden numbers, when once they shall have been properly placed in the calendar, must either be advanced or set back 1 day, with respect to the place where they stood in the preceding period, agreeably to the foregoing rules; except those numbers which shall happen to stand against the 4th and 5 th of April, to show the paschal new moons, or against the 17th or 18th of the same month to mark out the paschal full moons; both which numbers at some times, and only one of them at others, must keep the same place for that which was allotted to them in the immediately pre- ceding period. In order to determine at what times, and on what occasions, this exception is to take place; let it be observed, that in the months of January, March, May, and some others in our present calendar, as well as in the table above-mentioned, some of the golden numbers stand double or in pairs, and follow one the other immediately: while others, on the contrary, generally stand single and by them- VOL. XLVI.J PHILOSOPHICAL TRANSACTIOMS. 41 selves. Now, when any of those pairs, or two numbers which usually accom- pany each other, happen, in pursuance of the foregoing rules, to be prefixed the one to the 4th and the other to the 5th of April for the new moons, or the one to the 17 th and the other to the 1 8th of April for the paschal limits or full moons; and when any of those numbers, which generally stand single, are pre- fixed, according to the said rules, to the 5th of April for the new moons, or to the 18th for the full moons; in these cases those pairs or single numbers that are so situated, must not be set forward, or advanced at the beginning of the next period, but must keep their places during another period, if the foregoing rules direct all the golden numbers to be advanced a day; which must be com- plied with in respect to all the other golden numbers, except those so situated as above. Instances of which may be seen in the table, under the respective periods beginning with the years 19OO, 2600, 3100, and 3800. But if, in conformity to the foregoing rules, all the golden numbers are to be set one day backward, those pairs or single numbers, though situated as above-mentioned, must not keep their places, but must move one day backward, like all the other golden numbers; as they may be seen to do in the periods beginning with the years 2400 and 3600. VOL. X. G 4'2 PHILOSOPHICAL TRANSACTIONS. [anno 1750. A Table showing, by means of the golden numbers, the several days on which the Paschal limits or full moons, according to the Gregorian account, have already happened, or will hereafter happen ; from the reformation of the calendar a.d. 1582, to the year 41 99 inclusive. Golden Numbers from the Year 1583 to 1699, anc" I so on to 4199, all inclusive. Paschal full Moons. 1583 1700 1900 2200 2300 2400 2500 2600 2900 3100 3400 3500 3000 3700 3800 4100 Days of the to to to to to to to to to to to to to to to to Month, and 1699 i»99 21.Q9 2299 6 2399 17 2499 2599 2899 3099 9 3399 3499 I 3599 12 36'99 1 3799 12 4099 4J99 4 Sund. letters. 3 14 6 17 Mar. 21. c , 3 14 6 . 6 17 , 9 1 1 12 , .... 22. D 11 3 14 , 14 . 6 17 . '9 . 9 , 1 12 23. E , 11 , 3 14 3 14 , 6 17 . 9 • 9 , 1 24. F 19 , U , 3 3 14 , 6 17 17 , 9 25. G 8 19 11 U , 3 14 . 6" 17 6 17 '9 . . . . 26. A , 8 19 , 11 , u , 3 14 , 6 . 6 17 27. B 16 8 19 19 . 11 , 3 14 . 14 6 17 28. c 5 I'e . 8 19 8 19 , 11 . 3 14 3 14 6 .... 29. D , 5 16 , ■ 8 , 8 19 , 11 3 . 3 14 . ... 30. E 13 , 5 16 , 16 , 8 19 . 11 . 11 , 3 14 .... 31. F 2 13 , 5 16 5 16 8 19 • 11 . 11 3 Apr. 1. G , 2 13 . 5 , 5 16 . 8 19 , 19 11 .... 2. A 10 . 2 13 , 13 , 5 16 , 8 19 8 19 , 11 .... 3. B , 10 , 2 13 2 13 , 5 16 , 8 . 8 19 , . . . . 4. c 18 10 , 2 . 2 13 , 5 16 , 16 , 8 19 . . . . 5. 0 7 18 , 10 • 10 , 2 13 , 5 16 5 16 , 8 .... 6. E 7 18 , 10 , 10 2 13 , 5 , 5 16 . ... 7. F 15 , 7 18 , 18 , 10 , 2 13 , 13 5 16 8. G 4 15 7 18 7 18 10 , 2 13 2 13 , 5 . . . . 9. A 4 15 , 7 . 7 18 10 2 • 2 13 , 10. B 12 , 4 15 , 15 . 7 18 , 10 . 10 , 2 13 11. C 1 12 4 15 4 15 , 7 18 . 10 10 2 .... 12. D 1 12 4 4 15 . 7 18 18 , 10 , .... 13. E 9 , 1 12 . 12 , 4 15 , 7 18 7 18 10 . ... 14. F 9 . 1 12 1 12 , 4 15 . 7 7 18 , 15. G 17 9 . 1 , 1 12 4 15 15 . 7 18 .... 16. A 6 17 17 9 9 , , 12 12 4 15 4 15 15 7 .... 17. B 14 6 6 17 9 17 9 9 1 1 12 4 12 4 4 15 . . . . 18. c ... Ii9. D ... 20. E .... 21. F 22. G . .. 23. A 24. B 25. c To find the day on which the Paschal limit or full moon fells in any given yearj look, in the column of golden numbers belonging to that period of time in which the given year is contained, for the golden number of that year ; over-against which, in the same line, continued to the column entitled Paschal full moons, you will find the day of the month, on which the Paschal limit or full moon happens in that year. And the Sunday next after that day is Easter day in that year, according to the Gregorian account YOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 43 0/ the Morbus Strangulat onus. By John Starr, M.D. N° 495, p. 435. Dr. S. mentions, that there had been raging in the neighbourhood of Liskard for some time previous to Jan. 10, 1749, (the date when this account was written) a disease formidable in its advances, and fatal in its consequences, viz. an occult an- gina, called with some propriety morbus strangulatorius. Dr.Fothergill's sore throat with ulcers, and Dr. Cotton's St. Alban's scarlet fever, &c. are in his opinion but its shadows. None practising in those parts have reason to boast their success in attempting its cure. The way to cure disorders is first to know them. Where the deviations of nature are hidden, where we cannot discern how and in what manner the distressed functions suffer, the art of healing must have its difficulties. The sudden, and indeed unexpected death of some patients greatly alarmed him* He concluded the cause deeper than at first imagined. The case herewith sent, confirmed his conjecture. It is extraordinary and uncommon. Does (he asks) medical history afford its like? it is possible it may, but it had not fallen within the compass of his reading, or study. Tulpius's Observation, lib. iv. cap. ix. falls vastly short of it. The morbus strangulatorius, with great propriety and justice thus denominated, had a few years before reigned in several parts of Cornwall with great severity. Many parishes had felt its cruelty, and whole families of children, whence its contagious nature was but too evident, had, by its successive attacks, been swept off. Few, very few, had escaped. The disorder did not appear with the same train of symptoms in every subject. On the contrary, a vast difference was ob- servable; but then whatever, or how various soever, the symptoms might be, there was a certain degree of malignity, or signs of a putrid disposition of the juices, in all. Some, he was informed, had had corrosive pustules in the groin, and about the anus, eating quick and deep, and threatening mortification, even in the be« ginning. Others after a few days illness had numbers of the worst and deepest petechiae break out in various parts of their body. Such he had not seen. Many on the first attack had complained of swellings of the glands, as tonsils, parotids, submaxillary and sublingual glands, but frequently of no great importance. A few, from an internal tumour, had a large external oedematous swelling of the subcutaneous and cellular tunic, from the chin down to the thyroid gland, and up the side of the face. One such he was concerned with, the tumour broke in the fauces ; but, instead of a laudable pus, some ounces of a coftee-coloured ex ceedingly fetid matter were spit off. The man recovered. As respiration only suffered here by pressure, he rather chose to call this a malignant angina, than the true morbus strangulatorius. Not a few early in the disorder had gangrenous sloughs formed in their G 2 44 PHILOSOPHICAL TRANSACTIONS. [aNNO J750. mouths, and perhaps so early in some, that the disorder was scarcely complained of, till the slough was formed, so quick had it been in its progress. Others again, without any of the preceding symptoms, had only complained of a slight pain in swallowing, succeeded with a hot flesh, feverish pulse, never quick and weak, but as to the stroke quick, and sufficiently full and strong, a short, low, becking, hoarse cough, the patient generally so hoarse as to be difficultly under- stood after a day or two's illness, which sooner or later, for he never could ob- serve any certain period, was productive of a difficult, noisy, and strangulating respiration. These last, especially the former of them, he esteems as the pathog- nomonic symptoms of the real morbus strangiilatorius : the above-mentioned were rather symptomata causae, quam morbi. He had not mentioned a foetor oris, which, when it happened, was usually an early symptom, because, though some had it, others had it not. This respiration, however agonizing it appeared, had, especially in the begin- ning, its remissions and exacerbations. Its cause could not of course be perma- nent. He took it to be owing to a lodgement of some matter in or about the glottis, and larynx, through which the inspired air is obliged to pass ; while this matter was capable of being expectorated, and happened to be coughed off, the breathing for a time became free, and the patient' was delivered from the utmost seeming distress ; but, on its recollection, which, if the progress of the disorder could not be stopped, never failed to happen, this symptom again occurred, and the patient either died suddenly, or being worn out, or quite dispirited, sank away gradually, or, falling into convulsions, in these expired. He was called to a girl of 5 years old. Her tongue was quite clean ; she could move it every way as in health. Nothing morbid was seen in her mouth, or indeed fauces: she had a trifling pain in swallowing, it was felt on depressing the epiglottis for the passing the bole, not sufficient to prevent her from eating bread and butter, biscuit, figs. It was on the 4th day of her disorder she had the strangulating respiration, with a cough exceedingly hoarse. After the use of a stimulating gargle, &c. her cough became stronger, and she threw off a large quantity of white rotten flesh, or membranes, mixed with a slimy adhesive matter; her respiration became so easy, that she seemed to ail nothing. In 3 hours it grew again difficult, and gradually increased till it arrived at its former violence. Those about her fancied there was somewhat in the passage which ought to come off: the child gargled, and provoked her cough as far as she was able, but in vain. Her agonies increasing, she said, as well as she was able " I shall be choaked," and in a few minutes died. This case shocked Dr. S., being satisfied, that somewhat very extraordinary and uncommon could only occa- 'Sion so sudden, and seemingly, violent a death. He had frequently examined the matter those patients had at times spit. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 45 Though there was some difference in various subjects, yet he never once saw a well-digested or concocted phlegm, or mucus: on the contrary, the greatest part was of a jelly-like nature, glary, and somewhat transparent, mixed with a white opaque thready matter, sometimes more, sometimes less, resembling a rotten membranous body or slough. Such a slough he had seen generated on the skin of one of these patients in the neck and arm, where blisters had been before ap- plied. The blisters had been dressed with colewort leaves, and ran but little; but, contiguous to them, small red pustules, not exceedingly fiery, arose, which, sweating plentifully in a few hours, became quite white; these, hourly enlarging their bases, united, and covered a large surface, fresh pustules arising in the adjacent parts. This white surface had the aspect of an oversoaked membrane, which, being oversoaked, was become absolutely rotten. The part blistered, if not quite, was in effect dry, and the flux from the slough was incredibly great. If he mistook not, clothes 10 times double, the child's shift, a double bed-gown, were wet quite through, and a large spot was seen in the bed of some hands breadth, and this in a very few hours. He scratched the slough with his nail ; it separated with ease, and without being felt by the child. What , his nails took off afforded the same appearance with the matter of the spittle before-mentioned. Hence, he thought, he saw sufficient reason to convince him that the disorder in the larynx and aspera arteria was similar to this, generated in the same manner, and arising from the same internal cause; and supposing this conjecture true, the production of every symptom seems easy to be accounted for. Dea 1748, while the morbus strangulatorius was at Liskard, a child here and there had red pustules, not unlike the above, which broke out in the nape of the neck, and threw off a surprising quantity of thin transparent ichor, vastly glutinous when dry. These were easily cured in the beginning, if managed aright; but, being drawn with colewort leaves, or poulticed according to the direc- tion of our old female practitioners, the above mentioned slough was soon gene- rated. Dr. S. was desired to look on a poor person's child in this unhappy situa- tion, who, with little intermission for near 2 days, had bled profusely at the nose; her pulse was almost gone; the bleeding was with difficulty stopped; but, being quite exhausted, in about 6 hours she sunk in a faint fit. The slough had spread from shoulder to shoulder, extended full a third down her back, and seemed very thick. All treated in the above manner died. Scarifying af- forded no relief. Now, though this was not properly the morbus strangulatorius, yet he appre- hends it was analogous to it, and produced from the same cause; and it is likely, had the anatomical knife been employed, what was seen on the back of one might have been discovered in the aspera arteria of the other. There is a cir- cumstance which adds to the probability of this opinion, viz. in one or more in- 46 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. stances, these different disorders appeared in different subjects, in the same family, at the same time. What he had hitherto said, did not demonstrate the case to be as represented, but the following history throws the strongest light on this dark, mysterious affair, renders the disorder, by its consequences affrightful, even shocking to tlie imagination, accounts for its too common fatality, and must prove the great difficulty of the cure, if in itself possible, unless attempted with judgment in the very beginning. Dec. 11,. 1749, he was called to the son of Mr. Kitto, an honest and deserv- ing farmer in the parish of St. Eve, a lad aged 10^ years. This was the 7th day of his illness. His first complaints were, a pain in swallowing, not great; a cough, hoarse, vexatious, like an incipient catarrh, a pain on coughing shot into his ears. This was still felt at times; a thin ichor ran from his mouth, in great plenty, supposed to be a quart, or 3 pints daily. His pain in swallowing was now so trifling, that the Dr. saw him drink a considerable draught without removing the vessel. He was now so hoarse that he could scarcely be heard. His cough was rough, low, short, and ineffectual; breathed with much straitness and noise, especially in inspiration ; the wheezing or rattling might be heard at a great dis- tance, was always worse during a coughing fit, or for a short time after. When he spit by the cough, it was glary, but glutinous; a whitish rotten sort of stuff would sometimes accompany it ; its quantity never great. Examining his mouth, he could move his tongue every way without the least pain; forward it was clean, but behind a little furred. Depressing it with a spa- tula, a white body was seen on the velum pendulum palatinum and tonsils. Dr. S. desired Mr. Scotchburn, a surgeon present, to examine with his forceps, if this body adhered firmly to the velum, or was loose ; on trial he found it strongly adhered. The lad complained of no pain on his taking hold of it. The circum- ambient parts of a somewhat deeper red than natural; his breath stinking, and highly offensive. He was but little thirsty, pulse quick, but sufficiently strong; slept but little; what sleep he had was disturbed; he breathed much better up than in bed; here he was always in danger of suffocation, and feared it. After pronouncing a prognostic disagreeable to himself, and all concerned, the Dr. ordered the slough, as he then thought it, to be well rubbed once in 3 hours a mixture acuated with spir. sal. marin. by means of a silver probe armed with cotton, after which, an astringent, detergent, antiseptic gargle was to be fre- quently used, and a cordial mixture to be taken at proper intervals. After rubbing with the probe, &c. twice, and gargling often, in a violent fit of coughing with a deal of slimy filthy stuff from the pipe of the lungs, an irre- gular membrane separated from the velum palatinum. It was really the external and mucous coat of the part, was not rotten like a slough, but retained, though VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 47 dead, its membranous structure, was strong, would bear liandling, and stretch- ing without breaking. It was at first thick, having its fibres and cavities soaked with a very viscid and slimy matter, which, by washing in water, leaked off, when the membrane became evidently thinner. The lad immediately, it seems, breathed better, without that noise and wheezing heard before, and was less hoarse; not, he thinks, from the separation of the membrane, but from that load of filth discharged at the same point of time from the distressed respiratory passages. But, as usual, this relief did not prove lasting. In li hour the noisy respi- ration began anew, his hoarseness increased, and his cough, though short and low, was busy and vexatious; now he appeared as if quite strangled, and in the agonies of death; now he would again revive; for a few days he was interchange- ably in these different states; at length his father perceiving somewhat in his mouth which he thought thick phlegm, thrust in his finger and thumb, and, taking hold of it, drew it out. It was a hollow bag, as he thought, filled with rot and corruption, for a considerable quantity ran out of it. It was, when full, he said, as thick as his thumb, and of many inches in length. The agonies of the child, during these moments, were not to be expressed; his face was livid or black; but, being freed from this burthen, he soon revived, smiled, and said, " now I am easy." Being put to bed, he soon slept, and continued to have short naps for 2 hours. Dr. S. got to the house, being sent for in the beginning of the lad's extremity, a few minutes after the affair was thus concluded. The account greatly surprised him; but he was more surprised, when, on sight, he found the supposed bag was the mucous coat of part of the larynx, the whole aspera arteria, with the grand division of the bronchial ramifications. He spread it on paper, for the conveniency of carriage, being some miles from home, and thence took its like- ness with great exactness. There was something bloody visible about its middle. It was more rotten and tender than the former, also somewhat thicker, excepting where it belonged to the branches of the bronchia. What sweated from it was as sticking as bird-lime. It is probable this morbid affection ran through the whole bronchia ; for the ends plainly discovered a laceration ; consequently much more remained to be separated and discharged. He now complained of soreness in the pipe, and pointed to the first and second eosta, as the place of its termination. His inspiration was now free, soft, but short; his pulse was become a little more frequent and weaker. Examining his mouth, no ulcer or wound was discernible in that part of the velum, &c. It was smooth, clean, and looked only like a new skin not quite hardened. While the Dr. was in the house, he spit off" another membrane of an irregular figure, thin- ner than either of the former, but more than sufficient to cover a crown-piece. 48 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. It came from the fauces. After this he was informed he brought off with diffi- culty another tubular membrane of some length ; and whenever he had strength to expectorate, little bits of the same were observed mixed with a very slimy mucus. He lived 2 1 hours after the second coat was drawn from him, and died in the end somewhat suddenly, though in his perfect senses. Dr. S. adds, that he never saw one in this disorder attacked with a delirium.* Of the Strength of several of the principal Purging Waters, especially of that of Jessop's fVell. By the Rev. Ste. Hales, D. D. and F. R. S. IViih a Letter from Swithin Adee, M. D., F. R.S. on the Virtues of the said [Fell, N° 495, p. 446. An account of the several quantities of sediment which were found in a pound Avoirdupois of the following purging waters, evaporated away to dryness, in Florence flasks, cut to a wide mouth; viz. Marybone fields, near London, 24 grains. Peter-street brewhouse, Westminster, 27; Ebsham 34; Scarborough 40; — And it was found nearly the same by Dr. Shaw and Dr. Short: a little more or less according to the wetness or dryness of the seasons, y.,- of this in calcareous matter; the rest, mostly what is called nitrous salts, on account of the oblong crystals which it shoots into. — Dog and Duck, Lambeth 40-^ grains; Kilbum, 4 miles from London, in the way to Edgeware 43; Acton 44; Cheltenham, Gloucestershire, 60. Dr. Short found the following proportions in Cheltenham water, viz. — Sept. 1738, calcareous sediment -r4.-5- of 74 grains; Dec. 1738, -^of42; July 1739, TT "^ 70 ; He says it is the best and strongest nitro calcareous water in England, very bitter, having only a little subtile impalpable earth, mixed with its salt. Cobham well, a mile south of Church Cobham, Surrey, once 68 grains, ano- ther time 60 grains. Jessop's well, on Stoke Common, in Mr. Vincent's manor, about 3 miles southward of Claremont, Surrey, Sept. 11, 1749, after long dry weather, 82 grains in a pound of the surface water; Oct. 16, after a considerable quantity of rain, the surface water yielded but 60 grains. Nov. 21, the surface water yielded 65 grains. This great inequality of the strength of the surface-water put him upon trying whether the water at the bottom of the well, near the springs, were stronger than the surface-water. And he found that the lower water yielded 82 grains, the surface-water only 48 grains; and it was the same on a second evaporation of * The case last described was evidently a case of cynanche trachealis or croup ; but some of the preceding observations in Dr. Starr's paper, seem to relate to the cynanche maligna or gangrenous sore throat. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 40 those waters. Hence we see how much stronger the water near the bottom is, than at the surface ; even when the preceding rains have been but moderate ; for they had not as yet been sufficient to raise the springs in this country much. Hence we see that the stronger lower water may easily be come at by means of a pump ; as also, that the upper land springs, soon after rains, make the water near the surface weaker : but, in long dry weather, when there are no land- springs, the surface-water, and that at the bottom, are nearly of an equal strength : for it requires time for the saline mineral virtue to be equally diffused through a mass of that depth of water, whose upper part is incessantly weakened by a land-spring of fresh water. Hence we see how adviseable it is, in order to keep out the land-springs, to dig a narrow trench some feet depth, round the well, to be filled with stiff clay well rammed. The mineral virtue in this water seems to be much like that of Cheltenham, in its shooting into very bitter, regular, oblong crystals, which are, on that ac- count, called nitrous; though they are not a true nitre; for neither these, nor those of Cheltenham, will deflagrate or flash in touch-paper, nor on burning charcoal, as true nitre will do; some of which will retain their form and firmness for 1 7 months after being crystallized ; whereas the crystallized salts of several other purging waters have crumbled, and in a great measure wasted away in much less time : a greater proportion of the salts of Jessop's well shoot into oblong crys- tals, than those of Cheltenham , and its water also gives a stronger green tinc- ture, with violet-flowers. The purging quality resides chiefly in these crys- talline salts, and a small proportion of common salt ; some of which there is in all these mineral waters. The proportion also of its earthy calcareous matter, is but -pf.,- part of it ; which, like that of Cheltenham, is but little, in comparison of the much greater quantity of it in other purging waters : it is also soft and impalpable, like that of Cheltenham, and not harsh and coarse, as it is in some other purging waters. And as the quantity of purging salt in this water is considerably greater than in any other, so it is found by experience, that proportionably a less quantity of it suffices, which makes it sit the better on the stomach. It is also observed to exhilarate those who take it. It was observable of the sediment of several of these waters, that when dried, and while hot, there ascended plenty of invisible volatile salt fumes, so pungent that the nose could not bear them. Hence we may reasonably conclude, that the waters which abound most with purging salts, such as those of Jessop's well, should be proportionably preferable to weaker waters, which are strengthened by boiling half away ; by which not only the more subtile active parts are evapo- rated ; but those that are left are decompounded, and formed into new grossed combinations ; as are also the calcareous particles, which are so fine as to pass VOL. X. H 50 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. the filter before evaporation, but not after it. This was the reason which in- duced him to examine, by various repeated trials, and to give an account of the superior strength of Jessop's well water, above all others that he had examined or heard of. When Jessop's well was cleaned, Oct. l6, 1/49, after a considerable quantity of rain, after about half a foot depth of black muddy filth was taken out, then the natural fat sandy-coloured clay-bottom appeared ; through several parts of which the water oozed up at the rate of l6o gallons in 24 hours. The water which then came fr-esh from the spring gave a weak blush with galls ; but when put into bottles it did not do so next day ; a sign that there is some degree of steel in it. It was very observable, that the man who stood about 3 hours bare-legged in this well-water to clean it, was purged so severely for a week, that he said he would not venture, on any account, thus to clean the well again. And it was the same with another man, who cleaned the same well about ] 2 years since. And he was credibly informed by a merchant, that being in a warehouse in Egypt to see senna baled up, it had the like purgative effect on him. To get a satisfactory account of the efficacy of these waters, he desired Dr. Adee of Guildford, who has long prescribed them to his patients, to give his opinion of them ; which he did as follows. I have found very advantageous and uncommon effects from the use of the waters of Jessop's well. Some of my patients, who have drank them steadily and cautiously, have been cured of obstinate scurvies. As I had a long time ago reason to think there was a fine volatile spirit in them, I obliged some to drink them for a course of time at the well as an alterative, with very happy conse- quences. When I have ordered them as a purge, they have worked verj- smartlv, but have not dispirited. I am glad to have it in my power to confirm your sentiments by my own observations ; and am satisfied these waters, if con- tinued a proper time, and taken in a proper manner, may be rendered very be- neficial to mankind. Abstract of a Discourse intitled. Reflections on the Medals of Pescennius Niger, and on some Circumstances in the History of his Life ; written in French by Mr. Claude Gros de Boze, Keeper of the Medals in the French King's Cabinet, &c. and sent by him to Dr. Mead, who communicated it to this So- ciety. By John Ward, R. P. G., F.R.S. N° 495, p. 452. The learned author begins his discourse with observing, that no medals of the Roman emperors, who reigned during the high empire, are more rare, than those of Pescennius Niger ; that they are somewhat scarcer in silver, than in brass ; and that it is the general opinion of antiquaries, there is not one extant TOL. XLVI.3 PHILOSOPHICAL TRANSACTION. 51 in gold, though there have been counterfeits : as he shows from the account of several authors on such coins. In the years 1726 and 1727 he received accounts of one and the same gold medal of Pescennius, as brought from 4 different quarters ; first from Spain, then from Sicily, afterwards from Malta, and lastly from England. But he found it to be false, as all others had done, who had seen it. It had been cast from a silver one of that prince, on the reverse of which is the figure of the goddess Hope ; with the inscription of bonae spei, which is the most common of any. Those in the cabinets of Arschot and Saxe Gotha have likewise the same reverse, and doubtless from the same origin. And the like disappointment attended several other accounts. At length in July 1748, Mr. de Boze had fresh encouragement to pursue his inquir}' ; which he did with greater attention, and better success, than before. A barefooted Carmelite of the convent of Paris shewed him a letter, which he had received from one of his own order at Marseilles, who lately arrived from the Levant, where he had been employed as a missionary. His correspondent acquainted him, that he had a gold medal of Pescennius, which the curious at Marseilles were desirous to purchase, and had offered him a considerable sum for it ; but as he hoped to get more at Paris, especially if it was not in the king's cabinet, he desired him to let him know that, as also what value Mr. de Boze put upon it. His answer was, that he would certainly give a good price for it, if it was ancient ; but that he could offer nothing, till he had seen it. The owner therefore brought him the medal, which was fair, well preserved, and free from any thing, which might occasion the least suspicion ; so that he valued it considerably higher, than what had before been offered, and immediately pur- chased it for the king. Soon after he shewed it to the greatest connoisseurs and most curious persons at Paris, who were charmed with the sight of so valuable and unexpected a medal in the royal cabinet. And many both natives and foreigners being de- sirous of a draught of it, he ordered it to be engraved ; together with a Greek medallion in silver, no less rare in its kind, of the same emperor, which is also in the same cabinet, having been purchased at London by Mr. Vaillant of Mr. Falkner, father of Sir Everard. A print of both these pieces accompanies this paper. See fig. 3, 4, pi. i. The gold medal, fig 10, has on one side the head of Pescennius Niger crowned with laurel, with this legend, imp caes c pesc niger ivstvs avg. And on the reverse, the goddess Concord, represented by a female figure standing, with a diadem on her head, one of her hands elevated, and a double horn of plenty in the other ; and round the figure only the word concordia. For the letters pp placed below in the field, on the 2 sides of the figure, being the usual abbre- H 2 52 THILOSOPHICAL TRANSACTIONS. |^ANNO 1750. viation of pater patriae, are to be considered as part of the inscription sur- rounding the head of Pescennius. ^ Letter from Robert More, Esq.; containing several Curious Remarks in his Travels through Italy. N° 495, p. 464. Mr. M. thinks that travellers do not seem sufficiently to have considered the force and effects of steam, which may be formed by springs of water falling on a vast surface of the fluid lava, but talk too much of sulphur, deceived by the com- plexion of a salt that covers the ground in some places there. In the Solfatara he held a cold iron in the vent, and there ran down it a stream of water. When he went down into the crater on the top of Vesuvius, it was full of smoke. Yet he did not perceive it suffocating but thought it steam. What the guides call sul- phur, when he got it home, ran per deliquium. At Arienzo, a village half way to Beneventum, are coppice-woods, from which they make manna. They are of the tree which our gardeners call the flowering ash. The manna is procured by wounding the bark at the season, and catching the sap in cups: it begins to run (they used the scripture term piovere, i. e. to rain) the beginning of August ; and, if the season proves dry, they gather it 5 or 6 weeks. The king has a great revenue from it ; yet the tree grows as well in England. The fire among the snows, on the Apennines, he imagined to be of the same sort with that about a little well at Brosely* in Shropshire; of which the Society has had an account ; the same as of the foul air sent them from Sir James Low- ther's-|- coal pits ; and the like made by a gentleman with filings of iron and oil of vitriol. The flame when he saw it, was extremely bright, covered a surface of about 3 yards by 1, and rose about 4 feet high. After great rains and snows, they said, the whole bare patch, of about Q yards diameter, flames. The gravel, out of which it rises, at a ver)' little depth, is quite cold. There are 3 of these fires in that neighbourhood ; and there was one they call extinct. He went to the place to light it up again, and left it flaming. The middle of the last place is a little hollowed, and had in it a puddle of water : there were strong ebullitions of air through the water. But that air would not take fire; yet what rose through the wet and cold gravel flamed brightly. Near either of these flames, removing the surface of the gravel, that below would take fire from lighted matches. • See Pbilos. Trans. N" 482.— Orig. + N* 482, N°442.— Orig. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 58 Extract of a Letter from Mr. fVilliam Arderon, F.R.S. Containins, an Account of a Lhvarf; ivith a Comparison of his Dimensions with those of a Child under A Years old. Dated Norwich, May 12, 1750. By David Ershint Baker. N° 405, p. 467. John Coan, a dwarf, was born at Twitshall in Norfolk, in the year 1728, and has been shewn in this city for some weeks past. Mr. A. weighed him April 3, 1750, and his weight, with all his cloaths, was no more than 34 pounds. He likewise carefully measured him, and found his height, with his hat, shoes, and wig on, to be 38 inches. His limbs are no larger than a child of 3 or 4 years old : his body is perfectly straight : the lineaments of his face answerable to his age ; and his brow has some wrinkles in it, when he looks attentively at any thing. He has a good complexion, is of a sprightly temper, discourses readily and pertinently considering his education, and reads and writes English well. His speech is a little hollow, though not disagreeable ; he can sing tole- rably, and amuses the company that come to see him, with mimicking of cock's crowing, which he imitates very exactly. In 1744 he was 36 inches high, and weighed 27 -^Ib. His father says, when about a year old he was as large as children of that age usually are, but grew very little and slowly afterwards. On receiving the account of this little man, a * child of 3 years and not quite 9 months old, son of the late very worthy William Jones, Esq. f. r. s. was measured and weighed. This boy, though very lively and handsome, is no way remarkable for his size ; and therefore his dimensions and weight, compared with the dwarf's, may give a tolerable idea of the real smallness of the dwarf. The weight of the dwarf, with all his cloaths on, was no more than 34lb. The child's weight, with its cloaths likewise on, was 361b. The height of the dwarf, with his shoes, hat, and wig on 3Q^ inches ; the height of the child, without any thing on his head 37-Jg. inches ; and so propor- tionably in all the other dimensions. Concerning the Method of gathering Manna near Naples. By Robert More, Esq. N°495, p. 470. At Arienzo, a town between Naples and Benevento, he found an ash cop- pice, of 8 or 10 years growth, from which they collect manna. It seemed to have been tapped 2 years for that purpose ; the branches had been barked each year about an inch broad, and 2 feet high ; but he was told this was done by an inch at a time. They place a cup at the bottom of the wound, which they empty every 5 days ; • This child it would seem, must have been that celebrated character. Sir Wro. Jones, chief judge in India. 54 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. and the liquor becomes manna. They formerly let it dry on the tree; but the present way keeps it cleaner. The manna begins to run (they say in the scrip- ture style to rain) the beginning of August ; and if the season proves dry, they gather it 5 or 6 weeks. The king of Naples has so large a revenue from it, that he is extremely jealous of it, and during the season he guards the woods by Sbirri, who even fire on people that come into them, and he makes the stealing of the liquor death. Mr. M. believes it to be what our gardeners call the flowering ash ; the complexion of the bark and bud agrees with one of them he had in his garden at Lindley. The man who shewed the wood said it bore a pretty flower in the spring. At Pisa, in the physic garden, they shewed that tree in bloom as the manna-ash. The tree is indeed common enough in that neighbourhood : the Italians call it Orno. A botanist at Rome said it was the ornus ofiicinarum.* A physician at Benevento to the same purpose, that it was the ornus used in me- dicine. Observations on the Northern Lights, seen Feb. 15 and \Q, 1749-50. By -John Huxham, M. D., F. R. S. N° 495, p. 472. Feb. 15, 1749-50, in the evening there was a very vivid northern light, which darted forth several beautiful, crimson, and fiery-coloured rays ; wind n w b n 1, barometer 30. 2 ; 50 minutes past 8 a surprizingly bright and exceedingly white arch, about the breadth of a common rainbow, appeared in the heavens, ex- tending nearly from east to west ; it reached within 5 or 6 degrees of the western horizon, and ended about 8 or 10 above the eastern. It passed exactly between Castor and Pollux, and directly over Aldebaran, which appeared plainly through it. Near the top of the arch several very lucid, white, short, vibrating columns were attached to it ; none of them seemed above 6 or 7 degrees long, and did not appear to communicate in the least with the aurora borealis. About 9*^ 12™ the arch vanished ; but several white, bright, corruscating nubeculae remained here and there in the zodiac for 1 2 or 15 minutes longer. The aurora borealis continued more or less till midnight. Feb. 16, about 7 p- m. was another aurora borealis, though not quite so fiery and luminous as that of the night before : it continued till near 11. At S'' 56"^ p. m. exactly, such another arch appeared, very nearly of the same extent and direction, but not altogether so broad or lucid. This at first also passed be- tween the 2 bright stars of Gemini, but declined more and more to the south- ward, till it was 2 or 3 degrees to the south of Pollux. Its western limb, about 9, passed through the north shoulder of Orion : it quite disappeared about 10 or 12 minutes after. Of a Horse bitten by a Mad Dog. By John Starr, M. D. N" 495, p. 474. Dec. 1, 1745, a neighbour's large mastift'dog, mad, broke out in the night • Fraxinus Ornus, Lin. a more particular account of which is given in the 6oth vol. of these Trans. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 55 from the place where he was too carelessly confined ; and, by a rotten back win- dow, entered Dr. S.'s stable, fell upon his horse, and bit him in many places, as the shoulder, breast, and right nostril ; which was indeed much torn. He bled largely. The town being early alarmed by this mad dog, and the horse being found loose, his collar broke to pieces, wounded in many places, and much blood scattered up and down the stable, it was too justly concluded the dog had fallen upon him. According to Desault's method, and what Dr. James said, in a letter Dr. S. had from him on another occasion, would effectually prevent the ill consequences of this bite ; he immediately ordered the wounds to be well rubbed with a mer- curial ointment, ex axung. pore. jvj. argent, viv. jij. About §ij. were at times expended. Next morning he was bled 2lb. or more ; after which he gave him in milk* lichen ciner. terrest. 3vj. pip. nig. 5iiij. 5 mornings successively; which he repeated at the end of a fortnight for 4 mornings more. As the pulv. antilyssus was not in our shops, and no one in town knew the lichen but himself, he went with his servant Sunday forenoon, the day of his horse's misfortune, to seek it. What he found was, he fears too young ; for it seemed just coming from the earth, and the leaves were scarcely one third as large as its full growth. He got what he hoped might be sufficient ; and, after cleansing, perhaps too hastily dried it at the fire, that it might be ready for use the next day. The wounds healed up soon, without any other application ; and the horse fed uncommonly hearty after a day or 2, during which the fright had made him uneasy and fretful, and seemed to improve considerably in every respect. He omitted riding him for 20 days ; but about the 20th rode him 2 short journeys only. He travelled chearful and brisk, and he took care not to heat him. He saw him every day, but could in no respect discover any thing amiss. Dec. 25, two days before the full moon, his servant told him, that in the morning he trembled much on entering the horse-pool, and refused to drink at the watering trough ; but in the evening drank heartily at another well. This alarmed him ; but considering that horses frequently refuse to drink there, and that he drank in the evening, he was somewhat easy ; but ordered the servant if he refused next morning drinking at one, to try him at the other ; and if he refused at both, to let him immediately know it. Dec. 26, as soon as he entered the horse-pool, he trembled all over in a most surprizing manner, and would by no means attempt to drink. The servant im- mediately returned with him. Dr. S. ordered him to be led into a small pool of rain water which stood in the court. The trembling returned ; every muscle * See these Trans. N" 237, p. 49, anno 1697.— Orig. 56 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. was strangely agitated ; he looked as if he were melancholy on the water, smelt to it, but would not touch it. Being put into the stable, a bucket of pure clean water was brought to him; he eagerly thrust his mouth into the water, but, endeavouring to suck it, a convulsion seized him. Dr. S. was now satisfied he had a true aquae pavor. He was bled to about 3 pints, musk 3 ft. cinnab. ant. jj. made into a ball with cons, anthos was given him. In bleeding he once snapt at the smith, though well known to him, having shod him for years : and indeed this was the only time he attempted to bite any one. In about 1 hours after the musk was given him, Dr. S. offered him with his own hands about 2 gallons of white water warm : he drank it off without the least difficulty or hesitation. Had he dissolved in it 2 oz. of nitre, he had (he thinks) done well. Had the quantity of musk at first given been greater (for Dr. James writes, that he gives the above quantity of the best musk in a watchfulness remaining after a febrile delirium is removed,) or had Dr. S. now again repeated the same ball, he was apt to think the horse might have been saved (this being the Ton- quin method, even after the appearance of the hydrophobia ;) for he was as yet quiet and tractable. He went to him as usual, handled him, and he behaved as in his former health; he ate both hay and oats heartily. In the evening, about 9 o'clock, more of the white water was offered him, but he drank none. Dec. 27. This night the madness increased much ; for he had bitten the manger as far as he could reach, and made it quite ragged. In the morning he frequently bit his breast where the wound had been ; and when he happenol to take hold, violently drew up the skin with his teeth. Both these things he did during the day at times, but most in the morning. Dr. S. put a tub of water before him ; he greedily ran his nose into it ; but, endeavouring to drink, a dreadful convulsion seized him, which sometimes drew his buttock to the ground; at others his back was so hollowed with it, that his belly was brought almost down on the litter. During the convulsion he would groan in an affecting man- ner ; and frequently cry out. As soon as the convulsion was over, he repeated his endeavours to drink with the same cruel event ; and would, he believed, had the water stood before him, have repeated it the whole day. He still eat his allowance of hay and oats ; but when not eating, he was con- tinually thrusting out his tongue, and working with his lips, as if to moisten and cool them. His tongue was exceedingly dry, and of a blackish brown colour on the surface. As he eat oats. Dr. S. sometimes lamented he had not mixed turpeth. mineral, with them. He tried him with water about Q at night ; every thing was as in the morning ; only the convulsion was stronger, if possible, and more excruciating ; for he groaned deeper, louder, and in a more affecting tone. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 57 His breath was exceedingly hot ; it came from his nostrils like smoke from a chimney top ; he expanded his nostrils as if he had been violently running ; and the steam was visible for more than a yard distance. Dec. 28. This night he broke his collar in pieces, broke down the partition by which he was separated from the place of Dr. S.'s other horse, traversed the stable, attempted to get out ; in order to which he beat down the under half of the stable door; however, in the morning, being spoken to by the servant, he neighed, immediately went to his place, where he stood biting his breast and manger almost continually. His look was now become wild and furious, and about 10 o'clock Dr. S. ordered him to be shot. P. S. Dr. S. observed he was always worse, every symptom being aggravated at the time the moon came to the meridian ; which again, as the day declined, in some degree abated. Of a Monstrous Fetus without any Distinction of Sex. By Job Baster, Acad. Ca-s., F.R.S. N°495, p. 479. A woman about the 7th month of her pregnancy, was delivered of a monstrous child. The head was not of the natural round figure, but pointed at the top. The right arm was well formed; but the radius and ulna of the left much shorter. There was no appearance of any genital parts or anus : but instead the skin lay in rolls, with much fat. From the middle of the belly proceeded one foot only, ending as it were in one toe, but without a nail. Experiments on Substances Resisting Putrefaction. By John Pringle,* M.D., F.R.S. N''495, p. 480. Having been led to make some experiments and remarks on putrefaction, from the accident of having had an uncommon number of putrid distempers under his * Dr. (afterwards Sir) J. Pringle was descended from a good family in Scotland, where he was born in 1707. He studied first at St. Andrew's, next at Edinburgh, and afterwards at Leyden, where he attended the lectures of the celebrated Boerhaave, and took his degree of m. d. there in 1730. Not long afterwards he returned to Edinburgh. Here in 1734 he was appointed joint pro- fessor of moral philosophy with Mr. Scott. Through the recommendation of Dr. Stevenson, he was appointed, in 1742, physician to the Earl of Stair, who had the command of the British army that was destined to co-operate with the allies in Flanders. This was the foundation of our author's sub- sequent celebrity and fortune. He was afterwards made physician-general to the British forces in the Low Countries, and physician also to the Duke of Cumberland, whom he attended in his expe- dition against the rebels in Scotland. His services as army-physician ceasing at the peace of Aix-la- Chapelle, Dr. P. occupied himself in writing his Observations on the Jail Fever, and in making ex- periments on septic and anti-septic substances, which he communicated to the r. s., and for which he was honoured with the Copleian medal. In 1752 he published his great work, the result of long and diligent observation while he was attached as physician to the land forces, entitled Observations on Diseases of the Army. This work has gone through numerous editions, and its value is too well VOL. X. I SfS PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. care in the hospitals of the army, Dr. P. ventured to lay before the Society what he had found somewhat different from the common opinion, as well as some facts, which, as far as he knew, had not been mentioned before. 1. Finding it a received notion, that bodies by putrefaction became highly alkaline, he made the following experiments, to inquire how far this was the iactl The serum of human blood putrefied, made, with a solution of sublimate, first a turbid mixture, and afterwards a precipitation. This is one of the tests of an alkali, but scarcely to be admitted here ; since the same thing was done with recent urine (of a person in health), which is never accounted alkaline. The same serum did not tinge the syrup of violets green ; and made no effervescence when the spirit of vitriol was poured on it. He made the experiment twice on portions of different serum, both highly putrid; and once on water, in which corrupted flesh had been some time infused ; and the most he could find was, that, having given the syrup previously a small reddish cast with an acid, this colour was rendered fainter, but not destroyed by the putrid humours; and as to the effervescence, having dropped the spirit of vitriol into these liquors unmixed, and also diluted with water, the mixture was quiet, and only a few air bubbles established to need commendation here. It may be remarked however that in the treatment of scene disorders lie resorted too freely to venesection, his partiality for which was doubtless to be ascribed to the precepts of Boerhaave. In 1758 he was admitted a licentiate of the Lond. Coll. of Phys. Two or 3 years afterwards he was appointed physician to the queen's household. In 1763 he was made physician extraordinary to her majesty, and in the same year he was elected a fellow of the Lond. Coll. of Phys. In 1766 he was raised to the dignity of a baronet. He had been chosen f. r. s. in 1745. After he had been one of the council of that learned body for several years, he had the honour in 1772, of being called to the president's chair. In this situation he delivered, for a succession of years, some admirable discourses, on presenting Sir G. Copley's gold medal to those members who had distinguished themselves by the communication of important improvements and discoveries in science. These discourses were after- wards printed at the request of the r. s. They are 6 in number, and were delivered on presenting the aforesaid medals to Dr. Priestley, Mr. Walsh, Dr. Maskeleyne, astronomer royal, Mr. Mudge, and Dr. Charles Hutton, mathematical professor at Woolwich, for their respective papers. The medal for Captain Cook was assigned to him while he was out on his 3d voyage of discovery (1776), from which he never returned. About !: years after his elevation to the presidency of the k.s. Sir J. Pringle was appointed physician extraordinary to the king ; and various foreign academies had elected him one of thefr members. In the midst of these honours his health began to decline, insomuch that in 1778, finding the situation of president of the tt.s. to be attended with much inconvenience and fatigue; he felt himself under the necessity of resigning the chair, and was succeeded in that honourable situation by Sir Joseph Banks. After this Sir J. P. went to Scotland, and resided some time at Edinburgh ; but deriving no benefit from this change, he again removed to London, whero he died in 1782, being then in the 75th year of his age. Had Sir J. Pringle's merits been confined to his profession, he would still have held a conspicuous place in the list of British physicians ; but he possessed a mind capable of mastering more than one "branch of science ; and if he was justly celebrated for his skill in physic, he was equally entitled to distinction for his acquirements in philosophy. It is this union of general science with professional jskill, that gives a physic ian the fairest title to respect and reward. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. SQ appeared on shaking the glasses. On the whole, though there were some marks of a latent alkali in the putrid serum, they were so very faint, that one drop of spirit of hartshorn in a quantity of water equal to that of the putrid liquors, showed more of an alkali than 20 drops of any of the other. 2. It has been a maxim, that all animal substances, after putrefaction, being distilled, send forth a great quantity of volatile salt in the first water ; but Mr. Boyle (Nat. Hist, of Human Blood, vol. iv. p. 178, fol. ed.) found that this held good only in urine ; and that in the distillation of the serum of human blood putrefied, the liquor which first came over had little strength, either as to its smell or taste, and did not at first effervesce with an acid. And here it may be observed, that the chemists have generally applied those properties they discover in urine, to all the humours indifferently; whereas in fact there is a great diver- sity. For some animal substances, such as urine and bile, soon putrefy ; the saliva and the white of an egg slowly. Yet those that soonest corrupt do not always arrive at the highest degree of putrefaction. Thus the bile is soon corruptible, but the rankness of it is not to be compared to that of flesh; and the white of an egg is not only much less disposed to putrefy than the yolk, but, when corrupted, yields a different and less offensive smell. And it seems particular to stale urine to contain an alkaline salt, which, without distillation, makes a strong effer- vescence with acids : whereas most other animal humours putrefied, though of a more intolerable fetor, yet contain less volatile salt, less extricable, and not effer- vescing with acids. But what makes the difference between stale urine and other putrid substances still more specific, is its inoffensiveness with regard to health ; while the steams of most other corrupted bodies are often the cause of putrid and malignant diseases. Now, on finding in urine a much greater quantity of volatile salt, and that more easily separable than in any other humour, and that stale urine is the least noxious of putrid animal substances, so far then from dreading the volatile al- kali as the deleterious part of corrupted bodies, from this instance we may rather infer it to be a sort of corrector of putrefaction. 3. Daily experience shows how harmless the volatiles are, both when smelled to, or taken in substance ; but still there remains a prejudice, as if these salts, being the produce of corruption, should therefore hasten putrefaction ; not only in distempers where these salts are unwarily taken, but also in experiments out of the body. Now, as to the effects arising from the internal use of them, little can be said, unless the kind of disease was precisely stated. For supposing they were by their nature disposed to promote putrefaction ; yet if that is already begun, from a languor of circulation, and obstruction, then may the volatiles, by their stimu- lating and aperient quality, be the means of stopping its progress: and on the i1 60 PHILOSOPHICAL TKANSACTIONS. [aNNO 1750. Other hand, though they were really antiseptic, yet if the humours are disposed to corrupt from excess of heat or motion, these very salts, by adding to the cause, may augment the disease. So that, on the whole, it will be the fairest criterion of the nature of these volatiles, to inquire, whether out of the body they accele- rate or retard putrefaction. In order to decide this question. Dr. P. made repeated experiments of joining both the spirit and salt of hartshorn to various animal substances ; and had con- stantly found, that so far from promoting putrefaction, they have evidently hin- dered it ; and that with a power proportioned to their quantity. The trials have been made with the serum of the blood, and also with the crassamentum, after it had been dried by keeping. He once separated the thick inflammatory' crust of pleuritic blood from the rest of the mass ; and dividing it, he put one portion into distilled vinegar, the other into spirit of hartshorn ; and after keeping the infusions above a month in the middle of summer, he found the piece which lay in alkaline spirit as sound as that in the acid. Another time he put in one phial about H oz of an equal mixture of ox's gall and water, with 100 drops of spirit of hartshorn ; and in another as much of the gall and water without any spirit. The phials, being corked, were set by a fire, so as to receive about the degree of animal heat ; by which in less than 2 days, the mixture without the spirit be- came putrid, but the other was not only then, but after 2 days longer, un- tainted. He afterwards infused 2 drs. of the lean of beef with 2 oz. of water and J- a dr. of salt of hartshorn. Another phial contained as much flesh and water, with a double quantity of sea-salt : in a 3d was the flesh and water only, to serve by way of index. These phials were placed on a lamp-furnace, in a heat varying be- tween 94 and 104 degrees of Fahrenheit's scale. About 18 hours after infusion the contents of that phial which served as an index, were rank; and in a few hours more that with the sea-salt was also putrid ; but the flesh with the volatile alkali was sound, and continued so after standing 24 hours longer, in the same degree of heat : and that the smell of the hartshorn might occasion no decep- tion, the piece of flesh was washed from the salt, and still smelled sweet. About the same time he took 3 pieces of fresh beef, of the same weight as above ; and laying 2 of them in gallypots, he covered one with saw dust, and the other with bran : but the 3d piece being strewed with salt of hartshorn powdered he put into a 4-oz. phial which had a glass stopper. They were all 3 placed in the outside of a window exposed to the sun ; and the weather being warm, on the 3d day the flesh in the gallypots began to smell ; on the 4th were putrid. Next day the phial was examined ; when the flesh was washed from the salt, and found quite sweet. It was then dried and salted again with hartshorn ; and having stood in the house some weeks longer in sultry weather, it was looked at a second time, and observed to be as sound as before ; neither was the sub- \OL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 6l stance at all dissolved, but was of such a consistence as might be expected from common brine.* And lest it might be suspected, that the flesh in the gallypots by being more exposed to the air than that in the phial, became sooner putrid, he afterwards inclosed flesh in phials, as that with the hartshorn, and found the confinement rather hasten the putrefaction. Now, by these and many other experiments of the kind, finding that volatile alkaline salts not only do not dispose animal substances to putrefaction out of the body, but even prevent it, and that more powerfully than common sea-salt, we may presume that the same taken by way of medicine, will, caeteris paribus, prove antiseptic; at least we cannot justly suppose them corrupters of the hu- mours more than fermented spirits or sea-salt ; which taken in immoderate quan- tities may raise a fever, and thus accidentally be the occasion of corruption. 4. He had likewise made several experiments with the fixed alkaline salts, which have no less antiseptic power than the volatile. The trials were made both with the lie of tartar and salt of wormwood. But here we must not confound a dis- agreeable smell of such mixtures, with one that is really putrid ; nor the power those lixivials have of dissolving animal substances, with putrefactioni 5. From these experiments it was natural to conclude, since acids by them- selves were amongst the most powerful antiseptics, and the alkaline salts were likewise of that class, that the mixtures of the two to saturation would resist pu- trefaction little less than the acid alone. But in the trials he made on flesh with a spiritus mindereri, composed of vinegar saturated with salt of hartshorn, and also with the juice of lemons saturated with the salt of wormwood, he found the antiseptic virtue considerably less than when either the acids or alkalis were used singly. 6. As for the comparative virtues of these salts on flesh, he found 4. oz. of lemon-juice saturated with 1 scr. of the salt of wormwood resisted putrefaction, nearly as much as 15 grains of nitre ; but when the trial was made with ox's gall, 2 drs. of this mixture were more antiseptic than 1 scr. of that salt. Again, nitre compared with the dry neutral salts, weight for weight, is more antiseptic than any, in preserving flesh he had yet tried. Crude sal ammoniac came next to it and even exceeded it in the experiment with ox's gall. After these the sal diure- ticus, tartarus solubilis, and tartarus vitriolatus, seemed to have nearly the same power. He had mixed vinegar with a large quantity both of chalk and crabs-eyes, in order to neutralize it ; but, though seemingly saturated, by the effervescence ceasing, it still retained an acidity, and was found much more antiseptic than • The same piece after being kept dry a twelvemonth, was untainted, and as firm as at first. — Orig. 62 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. lemon juice neutralized with the salt of wormwood ; though this last acid be considerably stronger than vinegar. 7. Thus far have we considered the common neutral salts; which, however powerful in resisting putrefaction, are inferior to some resinous substances, and even some vegetables which he had tried. Thus myrrh, *in a watery menstruum was found at least 1 2 times more antiseptic than sea-salt. Two grains of cam- phor, mixed with water, preserved flesh better than 6o grs. of that salt : and he imagined, could the camphor be kept from flying ofi^, or concreting to the sides of the phial, that i gr. or even less, would have sufficed. An infusion of a few grs. of Virginian snake-root in powder, exceeded 12 times its weight of sea-salt. Camomile flowers have nearly the same extraordinary quality. The Jesuits' bark has it also ; and if he had not found it so strong as the two substances last men- tioned, he imputes that in part to his not being able to extract its embalming parts in plain water. Now vegetables possessing this balsamic quality are the more valuable, in that, being usually free of acrimony, they may be taken in much greater quantities than either spirits, acids, resins, or even the neutral salts. And as in the great variety of substances answering this purpose, there may be also some offensive or useful qualities annexed, it may not be amiss perhaps to review some part of the materia medica for this end. He adds, that, besides this extraordinary power in preserving bodies, he had discovered in some of these substances a sweetening or correcting quality, after putrefaction had actually begun. But these experiments he should lay before the Society some other time ; with a table of the comparative force of salts, and some further remarks on the same subject. y4n Attempt to explain an Ancient Greek Inscription, engraven on a Curious Bronze Cup with 2 Handles, and published with a Draught of the Cup by Dr. Pocoche, in his Description of the East, vol. ii. part 1, p. 207- By John IVard, F.R.S. N''495, p. 488. The diameter of the cup on the inside is about 13^ inches ; and the inscrip- tion is placed round the upper side of the rim. As jto the circular form of the inscription, we read in Pausanias of an instance not very much unlike this. Iphitus king of Elis is said to have restored the Olympic games, during which all hostilities ceased among the several states of Peloponnesus. Throwing the discus or quoit was one of the exercises performed in those games, and the discus of Iphitus was deposited in the temple of Juno at Olympia ; on which the cessation of arms, always observed at that solemnity, being engraved, was then publicly read. Which inscription, as the historian ob- VOL. XLVI.] PHILOSOFHICAL TRANSACTIONS. 68 serves, was not cut in straight lines, but in the form of a circle. This inscrip- tion Mr. Ward thinks may be thus read in the common Greek characters: M N A BAZIAErS M10PAAATHS EmATftP T012 ENTOS TOr TrMNAZIOr Em ATOPISTAIS rrA vel rotA aie2C2E. In Latin thus: Monumentum dedit Rex Mithridates Eupator Eupatoridis in gymnasio [vel intra gymnasium] Gypha [vel Gupha] servavit. The letters M N A stand by themselves over the rest, which are placed below them in the form of a circle. And the situation of these 3 letters shows over what words of the circular part they are placed. Abstracts of several Observations of Aurora Boreales lately seen. By Mr. Henry Baker, F.R.S. N° 405, p. 499. On Tuesday, Jan. 23, 1750, some unusual appearances were observed in the sky, at London, and the towns about it, by thousands of people during the whole evening, of which some accounts were laid before the r.s. And as ap- pearances of the like kind were observed in the heavens, the same evening, at great distances from London, the following is a description of what was seen at the city of Norwich by Mr. Wm. Arderon, f.r.s.; and also of what was observed at Wells (a little sea-port town in the same county of Norfolk, about 30 miles nearly due north from Norwich) by Mr. Joseph Sparshal, and sent by him to Mr. Arderon. This wonderful aurora began at 6 o'clock in the evening, at Norwich, with a blackish cloud in the n. e., out of which sprang up a streak of scarlet-coloured rays, of a surprizing beauty and vividness. This presently extended to within a few degrees of the s.w. horizon, passing directly through the zenith, and so con- tinuing near a quarter of an hour, when red and yellow columns began to rise upwards from every quarter. At 7 o'clock a black cloud rose up in the s.e. and quickly took a semicircular form, with light yellowish vapours ascending out of its upper edge, and representing a glory of an uncommon brightness. At 8 o'clock the black cloud was dispersed, but the yellow glory remained ; and round that sprang up another circle of red, which made the whole appear very tre- mendous. The reddish streams, as well as this last mentioned circle were sometimes s6 dense, that even stars of the first magnitude could not be seen through them. On Tuesday Jan. 23, the air at W^ was clear and serene during the great- 64 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. est part of the day, with a fresh breeze of wind at s.s.e. which terminated in an evening extremely remarkable for appearances in the heavens of an uncommon aurora borealia. At 15 minutes past 5, Mr. Sparshal noticed the foot of an arch, which formed an angle of about 10° with the n.e. part of the horizon. This arch shot out pointed streams like pyramids, of a fiery red colour, which generally ascended within a few degrees of the zenith, then vanished, and were immediately succeeded by others, from the n.e., where the principal magazine seemed to be. They continually shifted towards the e. and s.w. with sudden flashings and dartings ; but towards the west the appearances seldom altered. At 30 minutes past 5, a luminous stream, of a bright flame-colour, shot up on the N. side of the fiery arch, which still kept somewhat of that form, though fre- quently interrupted by shooting flashes from the n. e. At 40 minutes past 5, there appeared suddenly in the n.e. an elliptical corona, of an amazing bright- ness, elevated about 9° above the horizon, and having its longest diameter parallel to it. There shot up perpendicularly from this streams resembling columns of fliime intermixed with others of bright red. And so on, for various ' other curious appearances. At the beginning of these lights the mercury stood at 29.9, but quickly fell to 29.8. The wind at s.e. During part of the time there was an uncommon motion in the magnetic needle. And this evening were seen several of those meteors called falling stars ; particularly some which, on taking fire, left a long train of sparks behind them. Description of a Mariner s Compass contrived by Gowin Knight, M.B., F.R.S. N° 495, p. 505. Almost all the compasses on board merchants' ships have had their needles formed of 2 pieces of steel wire ; each bent in the middle, so as to make an ob- tuse angle ; and their ends, being applied together, make an acute one ; so that the whole represents the form of a lozenge ; in the centre of which, and of the card, is placed the brass cap. Mr. M. procured 20 cards, with needles of this kind fixed to them ; and after touching them with a pair of large bars, he tried each of them, with the same cup and pin, by drawing them aside 90° from the true point, and then seeing where they would rest. He found them all to vary more or less, either to the east or west ; and some of them as far as 8°. Few of them came to the same degree twice together ; and when they did, that was never the true point. In short, they not only varied from the true direction, but from each other, and from themselves. He then tried, by drawing them gently aside, how far he could make them stand from the true point, without returning ; and found they might frequently be made to do it at the distance of o VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 65 a whole point on either side. One of them, which generally varied 6 or 7 de- grees to the east, being drawn the same way, would stand at l6°. All these irregularities are owing to the structure of the needle : for the wires, of which it is composed, are only hardened at the ends ; and that is done by making the ends red-hot, and quenching them in water : if all these ends are not equally hard, or if one end be hardened higher up than the other, when they come to be put together, in fixing them to the card, that end which is hardest will destroy much of the virtue of the other ; by which means the hardest end will have most power in directing the card, and must consequently make it vary towards its own direction. If you retouch these wires when fixed to the card, the error will still remain ; for that wire which is best hardened will always be- come the strongest. ; The wires being disposed in the form of a lozenge is the reason why these' cards had so little force, that they might be made to stand at the distance of se- veral degrees, on either side the point from which they were drawn. For all magnetical bodies receive an additional strength by being placed in the direction of the earth's magnetism, and act proportionably less vigorously when turned out of it. So that, when such needles are drawn aside from their true point, 2 of the parallel sides of the lozenge will conspire more directly than before with the earth's magnetism ; and the other 2 will be less in that direction : by which means the first 2 sides will very much impede its return ; and the latter 2 will have that impediment to overcome, as well as the friction, by their own force alone. The needles that are used on board the men of war, and some of the larger trading ships, are made of one piece of steel, of a spring temper, and are broad towards the ends, but tapering towards the middle, where a hole is made to re- ceive the cap. At the ends they terminate in an angle greater or less, according to the skill or fancy of the workman. Now, though the worst of these are infi- nitely preferable to those of wire, yet the best of them are far fi-om being perfect. Every needle of this form has 6 poles instead of 2. There h one at each end, 2 vv'here it becomes tapering, and 2 at the hole in the middle. This is owing to their shape ; for the middle part being very slender, it has not substance enough to conduct the magnetic stream quite through from one end to the other. All these poles appear very distinctly, when examined with a glass that is sprinkled over with magnetic sand. Yet this circumstance does not hinder the needle from pointing true; but as it has less force to move the card, than when the magnetic stream moves in large curves from one end to the other, it is certainly an imperfection. Two needles, that were quite straight, and square at the ends, were found to VOL. X. K (U ..jr.v i|£i) oji4^„ oni 66 VHILOSOPHICAL TRANSACTIONS. [aNNO 1/50. have only 2 poles; but about the hole In the middle the curves formed of steel-dust were a little confused. These always came exactly to the same point, after vi- brating a long time ; and if drawn ever so little on one side, would return to it again without any sensible difference. We may therefore conclude, that a re- gular parallelopiped is the best shape for a needle, as well as the simplest ; with the holes for the caps as small as can well be contrived ; or if it can be made to answer the purpose without any hole at all, it will be still more perfect. Yet the common shape has one advantage which this has not : for being made broad at the ends, and slender in the middle, its weight is removed as far as possible from the centre : on which account, if it once points true, the friction at the centre cannot so easily put it in motion ; and its vibrations, when in motion, will be slower ; so that their limits may be more nicely observed, and the middle point between them is that where it would stand, if at rest. Being unwilling to part with these advantages, Mr. K. contrived a light circle of brass, of the same diameter with the card, which will supply a weight acting at the greatest distance from the centre of motion, and also serve to support the card ; which may now be made of thin paper, without any thing to stiffen it. So that the extraordinary weight of the brass ring is compensated in a great mea- sure by the lightness of the card. This ring is of service in another respect ; for being fixed below the card, and the needle above it, the centre of gravity is placed low enough to admit of the cap being put under the needle ; by which the hole in the needle becomes unnecessary ; and the latter being placed above the card, renders it easier to be touched with a pair of bars. Having thus completed the needle and card to his satisfaction, what chiefly remained, was to contrive such a cap and point as will have the least friction and be most likely to continue in a state of perfection. The caps in use are either of brass, a mixed metal, like that of a reflecting telescope, crystal, or agate. The first 2 will only admit of brass points, and the latter are rather too expensive for common use. He therefore thought of trying glass caps : he had 3 of them made by a' glass-blower, 2 of which he got polished : they were all set in brass, so as to screw into the same needle, which had also one of agate fitted to it. He compared them with that of agate, by trying with each of them how many vibrations the same card and needle would make, when drawn aside Q0°, on the same point ; which was a very small sewing needle. The number of vibrations with the agate cap, on the first trial, were 39, then 37, then 39 again ; with one of the glass caps it made 23, and then 20. This difference from the agate cap was so great, that he concluded the point must be damaged, and therefore chose a finer ; on which the same glass cap made 4 1 vibrations; then 43; and another glass cap made 47, and the next time 43. But the agate cap with this point made 51, 57, and 58 vibrations. The unpolished VOL. XLVI.] PHILOSOPHICAL TKANSACTIONS. 67 glass cap performed much the same with the others. He had 1 of them polished again by Mr. Smeaton; and in company with him repeated the same experi- ments ; but with no better success. The agate cap made always many more vi- brations than the glass one ; and generally with the latter the number diminished by repeated trials ; whereas with the agate cap it usually increased. These experiments made him lay aside the glass caps, and put him on think- ing how agate ones might be made with as little expence as possible. With this view he got a cap turned of ivoiy, in such a manner as to receive a small bit of agate at the top. This being ground concave, and polished on that side, where it formed the apex of the hollow cone in the cap, was capable of answering the purpose as well as if the whole had been agate, and was much lighter. These caps may be made cheap enough for common use ; and if good at first cannot easily be impaired. For a point, he chose a common sewing needle, and contrived to fix it in such a manner as to be taken out with the greatest ease, and replaced by another, if necessary ; by which means an excellent point may be always had with little trouble or expence. Common needles, when well tempered, have all the quali- fications that can be desired for the purpose intended. The smallest are strong enough to bear the weight of a card ; and are neither so soft as to be liable to bend, nor so hard and brittle as to break ; and the}' are generally better pointed than any that a common workman could pretend to make extempore. The specimen of the improved compass, shown to the Society, was made by Mr. Smeaton, a gentleman whose uncommon skill in the theory and practice of mechanics has enabled him to execute whatever Mr. K. proposed in such a man- ner as always to exceed his expectations : and not only so, but Mr. S. added a considerable improvement of his own. By a very simple contrivance he made the same instrument capable of serving the purposes of an azimuth and amplitude compass ; and that in a manner much preferable to any thing hitherto contrived; the description and use of which he has drawn up himself, for the perusal of the Society, as follows. On some Improvements of the Mariner s Compass, in order to render the Card and Needle proposed by Dr. Knight, of General Use. By John Smeaton, * Philosophical Imtrument-maher. N" 495, p. 513. The cover of the wooden box being taken off, the compass is in a condition to be used in the bittacle, when the weather is moderate : but when the sea runs •John Smeaton, a celebrated engineer, was born 1724, at Austhorpe, near Leeds j wherp. also he died in 1792, in the 69th year of his age. Mr. S. seems to have been born an engineer. The originality of his genius, and the strength of his understanding, appeared at a very early age. His K 2 68 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. high, as the inner box is hung very free on its centres, the better to answer its Other purposes, it will be necessary to slacken the milled nut, placed on one of the axes that supports the ring, and to tighten the nut on the outside that cor- responds to it. By this means the inner box and ring will be lifted up from the edges, on which they rest, when free ; and the friction will be increased, and that to any degree necessary to prevent the too great vibrations ; which otherwise would be occasioned by the motion of the ship. To make the compass useful in taking the magnetic azimuth, or amplitude of the sun and stars, as also the bearings of head-lands, ships, and other objects at a distance ; the brass edge, designed at first to support the card, and throw its weight as near the circumference as possible, is itself divided into degrees and playtliings were not those of children, but the tools men work with ; and he had always more amuse- ment in observing artificers work, and asking them questions, than in any thing else. Continually occupied in such pursuits, Mr. S. acquired, at 18 years of age, an extensive set of tools, and the art of working in most of the mechanical trades ; which he continued to work with occasionally to the end of his life. Mr. Smeaton's father being an attorney, he thought of bringing up his son to the same profession. Accordingly he was s«nt up to London in 1742 -, where after some time employed in tliat line, find- ing that the practice of the law did not suit the bent of his genius, as he used to express it, he wrote a strong memorial on the subject to his father, whose good sense, from that moment, left Mr. S. to pursue the bent of his genius in his own way. After this, Mr. S. continued to reside in London, where, before the date of the above paper, 1750, he had commenced philosophical instrument maker, which he continued to exercise for some time, and formed an acquaintance with most of the ingenious men of that time. In 17J3 Mr. S. was admitted f. r.s., and in 1759 he was honoured with the Society's gold medal, for his paper on the natural jxjwers of water and wind, to turn mills, and other machines de- pending on a circular motion. From about 1753 or 1754 Mr. S. seems to have practised as an engineer ; soon after which he undertook to rebuild the Edystone light-house, which he completed with stone in 1759. In 1764 he was appointed one of the receivers of the forfeited Derwentwater estate, applied to the uses of Greenwich hospital; which office beheld till 1777, when he resigned it in favour of Sir John Turner, a son of the Earl of Sandwich, then first lord of the admiralty. After this, Mr. S. going into full employment as an engineer, it would be endless to attempt to particularize all the great works he so ably conducted, as mills, wheels, engines, levels, canals, bridges, harbours, &c. in all which he was equally eminent. Particularly he saved from immediate destruction London bridge, after the opening of its great arch. Indeed as a civil engineer Mr. S. was perhaps unrivalled, certainly not excelled by any one. Astronomy was also, for amusement, a fa- vourite pursuit of Mr. S., and he made several curious instruments nf this kind for his friends, as well as for himself; with which, to the time of his death, he continued to make many observations. The chief of Mr S.'s publications, was his History of Edystone Lighthouse. Besides which, many of his reports and memorials on the different works he was concerned in, were occasionally printed in his life-time; as well as an ajlditional volume of the same since his death. He had also inserted in the Philos. Trans, a considerable number of valuable papers, both mechanical and astronomical, in most of the volumes from the year 1750 to 1776. A much larger account of this ingenious and worthy man may be seen in Dr. Hutton's Dictionary, from which the above particulars are extracted ; ot in the account of his life prefixed to the volume of his reports above mentioned. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 6p' halves ; which may be easily estimated into smaller parts if necessary. The di- visions are determined by means of a cat-gut line stretched perpendicularly with the box as near the brass edge as may be, that the parallax arising from a different position of the observer may be as little as possible. Under the card are 2 small weights, sliding on 1 wires, placetl at right angles to each other ; which, being movetl nearer to or farther from the centre, counterbalance the dipping of the card in different latitudes, or restore its equilibrium, where it happens by any other means to be got too much out of level. There is also added an index at the top of the inner box, which may be put on and taken off at pleasure, and serves for all altitudes of the object. It consists of a bar, equal in length to the diameter of the inner box , each end being fur- nished with a perpendicular stile, with a slit parallel to the sides. One of the slits is narrow, to which the eye is applied, and the other is wider, with a small catgut stretched up the middle of it, and from thence continued horizontally from the top of one stile to the top of the other : there is also a line drawn along the upper surface of the bar. These four, viz. the narrow slit, the hori- zontal catgut thread, the perpendicular one, and the line on the bar, are in the same plane, which disposes itself perpendicular to the horizon, when the inner box is at rest, and hangs free. This index does not move round, but is always placed on so as to answer the same side of the box. When the sun's azimuth is desired, and his rays are strong enough to cast a shadow, turn about the wooden box, till the shadow of the horizontal thread ; or, if the sun be too low, till that of the perpendicular thread in one stile, or the light through the slit in the other, fall on the line on the index bar, or vi- brate to an equal distance on each side of it, gently touching the box, if it vibrate too far : obsei-ve at the same time the degree marked on the brass edge by the catgut line. In counting the degree for the azimuth, or any other angle reck- oned from the meridian, make use of the outer circle of figures on the brass edge ; and the situation of the index bar, with regard to the card and needle, will always direct on what quarter of the compass the object is placed. But if the sun do not shine out sufficiently strong, place the eye behind the narrow slit in one of the stiles, and turn the wooden box about, till some part of the horizontal or perpendicular thread appear to intersect the centre of the sun, or vibrate to an equal distance on each side of it ; using smoked glass next the eye, if the sun's light be too strong. In this method another observer will be generally necessary to note the degree cut by the nonius, at the same time the first gives notice that the thread appears to split the object. From what has been said, the other observations will be easily performed ; only in the case of the sun's amplitude, take care to number the degree by the help of the inner 70 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. circle of figures on the card, which are the coinplements of the outer to go, and consequently shew the distance from east or west. The azimuth of the stars may also be observed by night ; a proper light serving equally for one observer to see the thread, and the other the degree on the card. It may not be amiss to remark further, that in case the inner box should lose its equilibrium, and consequently the index be out of the plane of a vertical circle, an accurate observation may still be made, provided the sun's shadow be distinct : for, by observing first with one end of the index towards the sun, and then the other, a mean of the 2 observations will be the truth. Fig. 3, pi. 13, is a perspective view of the compass, when in order for ob- servation. The point of view being the centre of the card, and the distance of the eye 1 feet; ab is the wooden box; CD are two milled nuts; by means of which the axes of the inner box and ring are taken from their edges, on which they move, and the friction increased, when necessary ; e f is the ring that sup- ports the inner box ; g h is the inner box ; and i is one of its axes, by which it is suspended on the ring ef; kl is the magnet or needle ; and m a small brace of ivory, that confines the cap to its place. See fig. 4. The card is a single varnished paper, reaching as far as the outer circle of figures, which is a circle of thin brass, the edge being turned down at right an- gles to the plane of the card to make it more stiff; o is a catgut line drawn down the inside of the box; for determining the degree on the brass edge; pqrs is the index bar, with its 1 stiles and catgut threads ; which being taken off from the top of the box, is placed in two pieces, t and v, notched properly to receive it ; w is a place cut out in the wood, serving as a handle. Fig. 4 is the card in piano, with the needle fixed on it ; being one third of the diameter of the real card. Fig. 5 is a perspective view of the backside of the card; where ab represents the turning down of the brass edge ; c is the under part of the ivory cap; d and E are the '2 sliding weights to balance the card; and f and g, 2 screws that fix the brass edge, &c. to the needle. Fig. 6 is the pedestal that supports the card, containing a sewing needle, fixed in 2 small grooves to receive it, by means of the collet c, in the manner of a port-creyon. At d the stem is filed into an octagon, that it may be the more easily unscrewed. Description of a Fish* shown to the Royal Society by Mr. Ralph Bigland, March 11, 1749-50 : drawn up by C. Mortimer, M. D., Sec. R.S. N°495, p. 518. This fish is smooth skinned, has no scales, nor teeth. It has one erect fin on • This fish is the Zeus Luna. /in. Si/st. Nat. Gmel. the Opah Pennt. Brit. Zool. VOL XliVI,} PHILOSOPHICAL TRANSACTIONS. fl on its back, which arises below its neck, and runs within a little of its tail. On each side about the middle, between its back and belly, behind the gills is a fin : from the bottom and middle of its belly, a little forward of the vent, arise 2 fins : from behind the vent runs one fin, within a little of the tail : the tail-fin is large and forked. Its eyes are large ; the irides are scarlet, encompassed with a circle of a gold colour verged with scarlet. Its nostrils are placed above its eyes. The back, and upper part of the body quite to the tail, is of a dark blue, or violet colour ; these, and the sides of the body, which were of a bright green, are all speckled with oblong white spots ; the chaps are of a pale red ; the nose, gills, and belly, of a silver colour ; and all the fins of a bright scarlet. It was 3 feet 7 inches long, and 3 feet 10 inches round in the thickest part, and weighed 82 pounds. Its mouth is small : its tongue thick, almost like a human tongue in shape, but rough, and thick-set with beards or prickles, which pointed backwards ; so that any thing might easily pass down, but could not easily slip back again ; while these might serve instead of teeth for retaining its prey or food. Its gills resemble those of a salmon. Its body grows very taper towards the tail ; and, fi"om being compressed to 10 inches thick, becomes near the tail almost round, and about 3 inches thick. The whole shape of this fish much resembles the sea-bream ; but it differs in size, being much larger, and in not having teeth nor scales. The fin standing erect on the back, has some aculei next the neck, and rises up 8 inches ; but in the middle diminishes to 1 inch ; and near the tail rises again to about 3 inches. The belly-fin opposite to this spreads 3 inches near the tail, and diminishes towards the vent. The tail- fin is forked, and spreads 12 inches. The gill-fins are g inches long, and 3 wide at their basis. The 2 belly-fins were 1 1 inches long, and 3 wide at their basis. It seems to be a new species offish, not yet described by any author: ^ but on the coast of Guinea is known by the name opah. Mr. Bigland said, that, on opening it, all its bowels would have gone into a quart mug ; that the flesh of the fore part was firm, and looked like beef, and the hinder part like fine veal ; that the bones were like those of quadrupeds ; particularly the shoulder blades, which resembled those of sheep. On the Extirpation of an Excrescence from the Womb. By John Burton of York, M. D. N° 495, p. 520. The wife of one Chapman, a whitesmith, at Selby, 10 miles from York, up- wards of 7 years since, lay in of her last child, and had a tolerable easy labour : soon after which, she had v/hat she called the fluor albus, that continued ever since, and increased on her ; insomuch that she says, she has sometimes had such a discharge as to wet the place she sat on through all her clothes. For some months before Dr. B. was concerned for her, she began to com- 74 PHILOSOPHICAL TRANSACTIONS. [anNO 1750. plain of a pain and weight in the uterus ; which increased as the substance grew in bulk. ; and at last the excrescence was so large as to appear outwards, and then it grew very fast. The patient consulted her midwife, who thought the womb had come out ; but was so prudent as not to do any thing ; and desired they would call in better advice. Accordingly they sent for Mr. Fell, an eminent man-midwife and surgeon in this city ; who, not having met with a case like that, desired Dr. B. also to go and see her , which was in December last (1749.) The substance not only filled, but extended, the entrance into the vagina. Dr. B. introduced a finger into the passage, and soon found the ex- crescence to be less in bulk there, than what appeared without the body. He followed the substance till he reached the os uteri, which he found chiefly filled up with the neck or smallest part of this substance, leaving only a small part of the OS tincae to be perceived on the left side, obliquely towards the back. He . tried to penetrate the os tincaa with the end of his finger, but could not ; how- ever, he so far opened it, as to let out a sort of bloody ichor, which was a little offensive in smell. Hence, and from other inquiries, he concluded that she had an ulcer just within the os uteri, from the edge of which the fungus or ex- crescence grew. The patient complained of a pain in the uterus and back, was very faint, and frequently was provoked to vomit, with a feeble pulse, and sometimes sweat. On consultation it was thought proper to tie a ligature as high up within the vagina as the surgeon could reach : which being done, and some internal me- dicines being ordered, they left her. And 4 or 5 days after, the excrescence dropped off" at the ligature. Tlie patient afterwards, in part, recovered her strength ; though she was not in a good state of health, and her fluor albus, as she called it, was still trouble- some to her. The excrescence was very solid, of a dark liver colour, and, while adhering to the uterus, was quite insensible. When cut in two, it resembled the solid substance taken out of cancers. The Eclipse of the Moon, June 8, 1750, observed in Surry -street in the Strand. By Mr. John Catlin and Mr. James Short, F. R. S. N° 496, p. 523. About half an hour after 9 o'clock, the clouds clearing away, they saw the moon then totally eclipsed ; though considerably brighter on the east than on the west side ; by which -they found that she was then past the middle of the eclipse. They then observed the Emersion, or end of total darkness, at Q^ 45" O' End of the eclipse at 10 51 30 VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 73 Continuation of the Experiments on Substances Resisting Putrefaction. By John Pringle, M.D., F.R.S. N° 496, p. 525. I . Three pieces of the lean of fresh beef, each weighing 2 drs. were put se- parately into wide mouthed phials. Two ounces of cistern-water were added to each ; in one were dissolved 30 grs. of sea-salt ; in another 60 ; but the 3d con- tained nothing but flesh and water. These bottles were little more than half full ; and, being corked, were placed in a lamp furnace, regulated by a ther- mometer, and kept about the degree of human heat. About 10 or 12 hours after, the contents of the phial without salt had a faint smell ; and in 3 or 4 hours more were putrid.* In an hour or 2 longer the flesh with the least salt was tainted ; but that which had most, remained sweet above 30 hours after infusion. This experiment was often repeated with the same result, making allowance for variations of the degree of heat. The use of this experiment was for making standards, forjudging of the septic or antiseptic strength of bodies. Thus, if water with any ingredient preserved flesh better than without it, or better than with the additions of the salt, that ingredient might be said to resist putrefaction more than water alone, or with 30 or 60 grs, of sea-salt. But if, on the other hand, water, with any addition, promoted corruption more than when pure, the substance added was to be reckoned a septic, or hastener of putrefaction. The following experiments were therefore all made in the same degree of heat with the quantity of flesh, water, and air, as above specified; together with such septic or antiseptic substances, as afterwards mentioned, and were all compared with the standards. But whereas the least quantity of salt preserved flesh little longer than plain water. Dr. P. always compared the several antiseptic bodies with the greatest quantity of salt ; so that whenever any substance is said to oppose putrefaction more than the standard, he means more than 60 grs. of sea-salt. He began with examining other salts, and compared them in the same quan- • tity with the standard ; which being of all the weakest, he supposed it equal to unity, and expressed the proportional strength of the rest in higher numbers in the following table. A Table of the Comparative Powers of Salts in resisting Putrefaction. Sea-salt 1 Tartar, vitriolated 2 Sal gemmae. 1 -|- Spiritus mindereri 2 • It is to be observed, that these pieces were all entire ; but when they are beat to the consistence of a pap, with the same quantity of water, the putrefaction then begins in less than half the time mentioned here. — Orig. VOL. X. L 74 PHILOSOPHICAL TRANSACTIONS. |_ANNO 1750. Tartarus solubilis 2 Salt of hartshorn 4+ Sal diureticus 2+ Salt of wormwood 4 + Crude sal ammoniac. 3 Borax 12+ Saline mixture 3 Salt of amber 20+ Nitre 4+ Alum 30+ In this table the proportions are marked by integral numbers ; it being hard, and perhaps unnecessary, to bring this matter to more exactness ; only to some the sign + is added, to shew that those salts are stronger than the number in the table by some fraction ; unless in the last 3, where the same sign imports that the salt may be stronger by some units.* The tartar vitriolated is rated at 2 ; though more than 30 grs. of it was taken to equal the standard : but per- ceiving it was not wholly dissolved, an allowance was made accordingly. On the other hand, as part of the hartshorn flies off, its real force must be greater than what appears by the table. The salt of amber is likewise volatile ; and as 3 grs. of it were found more preservative than 6o grs. of sea-salt ; it may therefore be much more than 20 times stronger. This is indeed an acid salt ; but as the acid part of it is inconsiderable, this high antiseptic power must be owing to some other principle. The sp. minder, was made of common vinegar and salt of harts- horn ; the saline mixture of salt of wormwood saturated with lemon juice. The alkaline part in either of these mixtures with water only, would have resisted with a power of 4 + ; so that the acid added rendered these salts less antiseptic ; viz. the sp. minder, by a half, and the saline mixture by a 3d part : which was a circumstance very unexpected. Next he proceeded to try resins and gums, and began with myrrh. As part of this substance dissolves in water, 8 grs. were made into an emulsion ; but most of it subsiding, he could not reckon on a solution of more than 1 or 2 grs. which nevertheless preserving the flesh longer than the standard, we may account the soluble part of myrrh perhaps about 30 times stronger than sea-salt. Aloes, asa fetida, and the terra japonica, dissolved in the same manner as myrrh, like it subsided, and with the same antiseptic force. But gum ammoniac and sagapenum shewed little of this virtue : whether it was that they opposed putrefaction less, or that all the antiseptic principle fell with the grosser parts to the bottom. Three grains of opium dissolved in water did not subside, and resisted putrefaction better than the salt. But more air than usual was gene- rated, and the flesh became tenderer than with any of the stronger antiseptics. * Five grs. of borax was the smallest quantity compared with sea-salt ; but holding out so much longer, he suspected 3 grs. would have been sufficient} in which case the force of this salt was to be estimated at 20 : a singular instance of the strength of salt not acid. One grain of alum was weaker than 60 grs. of sea-salt; but 2 grs. were stronger. The power therefore of alum lies between 30 and 60 ; but it seemed nearer the first number. — Orig. AOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. JS Of all the resinous substances, camphire resisted most ; 2 grs. dissolved in 1 drop of sp. of wine, 5 grs. of sugar, and 2 oz of water, exceeded the standard; though during the infusion most of the camphire flew off', swam at top, or stuck, to the phial. Suppose only the half lost, the remainder is at least 6o times stronger than salt ; but if, as he imagined, the water suspended not above a 10th part, then ciimphire will be 300 times more antiseptic than sea-salt. That nothing might be ascribed to the minute portion of the spirit, used in this ex- periment, he made another solution of camphire in a drop or 2 of oil, and found this mixture less perfect, but still beyond the standard. 4. He made strong infusions of camomile-flowers, and of Virginian snake- root ; and finding them both greatly beyond the standard, he gradually lessened the quantity of these materials, till he found 5 grs. of either impart a virtue to water superior to 6o grs. of salt. Now as we cannot suppose these weak infusions contained \ gr. of the embalming part of these vegetables, it follows, that this must be at least 1 20 times more antiseptic than common salt. He also made a strong decoction of the bark, and infused a piece of flesh in 2 oz. of it strained; which flesh never corrupted, though it remained 2 or 3 days in the furnace, after the standard was putrid. In this time the decoction became gradually limpid, while the grosser parts subsided : by which it appears, that a most minute portion of the bark intimately mixed with water (perhaps less than of the snake-root, or camomile-flowers) is possessed of a very extraordinary antiseptic force. Besides these, pepper, ginger, saffi-on, contrayerva-root, and galls, in the quantity of 5 grs. each, as also 1 0 grs. of dried sage, of rhubarb, and the root of wild valerian,* separately infused, exceeded 6o grs. of salt. Mint, angelica, groundivy, senna, green tea, red roses, common wormwood, mustard, and horse-radish, were likewise infiised, but in larger quantities, and proved more antiseptic than the standard. And as none of these can be supposed to yield in the water above 1 gr. or 2 of the embalming principle, we may consider them all as very powerful resisters of putrefaction. Further, he made a trial with a de- coction of white poppy-heads, and another with the expressed juice of lettuce, and found them both above the standard. By these specimens we may now see how extensive antiseptics are ; since, be- sides salts, fermented spirits, spices, and acids, commonly known to have this property, many resins, astringents, and refrigerants, are of the number ; and even those plants called anti-acids, and supposed hasteners of putrefaction ; of which class horse-radish is particularly antiseptic. And indeed after these trials, • Though the experiment was only made with 10 grs. of the powder of this root, yet con- sidering how long that quantity resisted putrefaction, we may reckon the valerian among the strongest antiseptics.^-Orig. l2 76 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. he expected to find all dissolvable substances endowed with some degree of this quality; till on further experiments, he perceived some made no resistance, and others promoted corruption. But before entering on that part of the subject, he deems it proper to relate some other experiments more nearly connected with the preceding. 5. Having seen how much more antiseptic these infusions were than sea-salt, he then tried whether plants would part with this virtue without infusion. For this purpose, having 3 small and thin slices of the lean of beef, he rubbed one with the powder of the bark, another with snake-root, and a third with camo- mile flowers. It was in the heat of summer, yet, after keeping these pieces for several days, he found the flesh with the bark but little tainted, and the other 2 quite sweet. The substance of all the 3 was firm , particularly that with the camomile, which was so hard and dry, that it seemed incorruptible. Why the bark had not altogether the same effect, was probably owing to its close texture. 6. He had also made some attempts towards the sweetening of corrupted flesh, by means of mild substances ; because distilled spirits, or strong acids, the only things known to answer this intention, were of too acrid and irritating a nature to be thoroughly useful, when this correction was most wanted. As for salts, besides their acrimony, it is well known that meat once tainted will not take salt. A piece of flesh weighing 1 drs. which in a former experiment had become putrid, and was therefore very tender, spongy, and specifically lighter than water, was thrown into a few ounces of the infusion of camomile-flowers, after expressing the air, to make it sink in the fluid : the infusion was renewed twice or thrice in as many days ; when, perceiving the faetor gone, he put the flesh into a clean bottle, with a fresh infusion ; and this he kept all the summer, and had it then by him, quite sweet, and of a firm texture.* In like manner he had been able to sweeten several small pieces of putrid flesh, by repeated affusions of a strong decoction of the bark ; and he constantly observed, that not only the corrupted smell was removed, but a firmness restored to the fibres. Now, since the bark parted with so much of its virtue in water, it was na- tural to think it would still yield more in the body, when opened by the saliva and bile ; and therefore it was by this antiseptic virtue it chiefly operated. From this principle we might account for its success in gangrenes, and in the low state of malignant fevers, when the humours are so evidently putrid. And for inter- mittents, in which the bark is most specific, were we to judge of their nature, from circumstances attending them in climates and seasons most liable to the distemper, we should assign putrefaction as a principal cause. They are the • This piece was kept a twelvemonth in the same liquor, and was then firm and uncor- rupted.— Orig. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. ff great endemic of all marshy countries, and rage most after hot summers, with a close and moist state of air. They begin at the end of summer, and continue through autumn ; being at the worst, when the atmosphere is most loaded with the effluvia of stagnating water, rendered more putrid by vegetables and animal substances that rot in it. At such times all meats are quickly tainted ; and dysen- teries, with other putrid distempers, coincide with these fevers. The heats dis- pose the humours to acrimony ; the putrid effluvia are a ferment ; and the fogs and dews, so common to those climates, stop perspiration, and bring on a fever. The more these causes prevail, the easier it is to trace this putrefaction of humours. The nausea, thirst, bitter taste of the mouth, and frequent eva- cuations of putrid bile, are common symptoms and arguments for what is ad- vanced. We shall add, that in moist countries, in bad seasons, the intermit- tents not only begin with symptoms of a putrid fever, but, if unduly managed, easily change into a putrid and malignant form, with livid spots and blotches, and mortification of the bowels. But, as a thorough discussion of this question might carry him too far from the present subject, and be unseasonable here, he refers it to its proper place, and only remarks, that whatever medicines (be- sides evaqjiations and the bark) have been found useful in the cure of intermit- tents, they are, so far as he knows, all highly antiseptic ; such are myrrh, cam- phire, camomile-flowers, wormwood, tincture of roses, alum with nutmeg, vi- triolic or strong vegetable acids with aromatics. Thus far are only related experiments on flesh, or the fibrous parts of animals ; he next intends to shew what effects antiseptics have on the humours ; for though from analogy we may conclude, that whatever retards the corruption of the solids, or recovers them after they are tainted, will act similarly on the fluids ; yet, as this does not certainly follow, he judged it necessary to make new trials ; which, with some experiments on the promoters of putrefaction, the reverse of the former, will be given hereafter. Concerning a Flat Spheroidal Stone having Lines Regularly Crossing it. By Mr. Joseph Piatt, of Manchester. N° 496, p. 534. A man found a stone at Ardwick, 7 feet deep, near this town, in driving a slough through some gret stone. It is what is called a nodule, of a close, com- pact, smooth matter ; was incrustated with coarser earth, or soft stone ; is 3 inches and a half diameter ; formed not unlike one of the echini marini ; except the papillas or small protuberances, which it wants. It had 4 white seams, about the thickness of a horse-hair, which quarter the stone very correctly. The angles are exactly the same, and correspond so well, that it would require thp nicest mathematical head and hand to draw the like. 78 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. On Bees, and their Method of Gathering IVax and Honey. By Arthur Dobbs, Esq. N° 496, p. 536. The only 2 things in which Mr. Dobbs differs from M. Reaumur, are, thpt he apprehends Mr. R. says, the bees range from flowers of one species to those of another, while they are gathering one load ; so that the farina, or crude wax, loaded on their legs, is from different species of flowers ; which is contrary to what Mr. D. observed. The other thing that he differed from him in is, that he says the wax is formed in the bee, from the crude wax, or farina (so far Mr. D. agrees with him :) but by his observations, he says, after digestion it is dis- charged upwards by the mouth ; whereas, by Mr. D.'s observations, it is the faeces, husks, or shells of the farina or crude wax, after digestion, discharged by the anus. As to the first, says Mr. Dobbs, I have frequently followed a bee loading the farina, bee-bread, or crude wax, on its legs, through part of a gr^at field in flower ; and on whatever flower it first alighted and gathered the farina, it con- tinued gathering from that kind of flower ; and passed over many other species of flowers, though very numerous in the field, without alighting on, or loading from them ; though the flower it chose was much scarcer in the field than the others : so that if it began to load from a daisy, it continued loading from the same, neglecting clover, honeysuckles, violets, &c. ; and if it began with any of the others, it continued loading from the same kind, passing over the daisy. So in a garden, on the wall-trees, I have seen it load from a peach, and pass over apricots, plumbs, cherries, &c. yet made no distinction between a peach and an almond. Now M. Reaumur, in his memoir on the bee's making honey, mentions Aristotle's observation of the bee's loading or gathering from one species of flower without changing; not quitting a violet to gather fi-om a cowslip ; which he says is not justly founded; for he has observed frequently a bee on a large border gathering from flowers of different species. If M. Reaumur only means that, when the bee gathers honey, it takes it indifferently from any flower, I can say nothing against it; but, if he intends it to mean the bee's loading the farina on its legs, then my observation directly contradicts it. What further confirms my observation is this, that each load on the legs of a bee, is of one uniform colour throughout, as a light red, an orange, a yellow, a white, or a green, and is not on different parts of the load of a different colour ; so that as the farina of each species of flowers, when collected together, is of one uniform colour, the presumption is, that it is gathered from one species. For, if from different kinds, part of the load might be of one colour, and part of another. TOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 7Q Another observation to confirm the same fact is, that bees, in the height of the season, return to their hives with loads of very different magnitudes, some having loads as large as small shot, while others have very small loads ; it cannot be conceived that this difference is from the inactivity or sloth of the bee in col- lecting its load, but rather from the scarcity of the flowers, on which it first began to load. Now, if the facts be so, and my observations true, I think that Providence has appointed the bee to be very instrumental in promoting the increase of ve- getables ; but otherwise, might be very detrimental to their propagation ; and at the same time they contribute to the health and life of their own species. From the late improvement made by glasses, and experiments made, in ob- serving the works of nature, it is almost demonstrable, that the farina on the apices of flowers, is the male seed ; which entering the pistillum or matrix in the flower, impregnates the ovum, and makes it prolific. It is often necessary to have wind and dry weather to waft this farina to the pistillum, and from flower to flower, to make the seed prolific : and we find in wet seasons, that grain, nuts, and fruit, are less prolific, by the farina's not being properly conveyed to the pistillum ; and also in very hot dry weather, from clammy honey-dews, or, more properly sweet exudations from the plants themselves, which clog the farina, and cause blasts and mildews. Now if the farina of specifically different flowers should take the place of its own proper farina in the pistillum, like an unnatural coition in the animal world, either no generation would happen, or a monstrous one, or an individual not capable of further generation. Now if the bee is appointed by Providence to go only, at each loading, to flowers of the same species, as the abundant farina often covers the whole bee, as well as what it loads on its legs, it carries the farina from flower to flower, and by its walking on the pistillum and agitation of its wings, it contributes greatly to the farina's entering into the pistillum, and at the same time prevents the heterogeneous mixture of the farina of different flowers with it ; which, if it strayed from flower to flower at random, it would carry to flowers of a dif- ferent species. Besides these visible advantages, it may be of great benefit to thdr own species and society ; for, as this farina is the natural and constant food of the bees, during one half of the year, and from this digested, as accurately observed by M. Reaumur, is the bouillee and jelly formed; which is lodged for the food of the young bees, till they become nymphae : it is also necessary that its stores should be lodged in the cells adjoining to the honey, for their winter provision ; without whicii, M. Reaumur observes, they would be in danger of dying of looseness, their most dangerous malady. It seems therefore highly reasonable to believe, that different kinds of farina 80 - PHILOSOPHIC A.L TRANSACTIONS. [aNNO 1750. may have different physical qualities : so that, by making collections of the same kind in each cell, they may have proper remedies for themselves against ailments we have no knowledge of, which otherwise they would not have, if they were filled at random from all kinds of flowers. These further advantages, directed to them by Providence, seem to add weight to my observations, and are a pre- sumptive proof that they are true. The only thing, besides the former, in which my observations differ from M. Reaumur, is in the manner the wax is made and emitted by the bee. I absolutely concur with him, that the wax is formed by digestion in the bodies of the bees, and is emitted by them, and then becomes wax ; and that it is almost impracticable to form wax any other way, unless the wax extracted from the myrtle-berries in America by boiling be an exception from it. By M. Reaumur's observations, he forms his opinion, that after the bee has fed upon the farina, or bee-bread, and it has passed through the first stomach (which is the reservoir where the honey is lodged, from whence it is discharged upward by its mouth into the cells) it is conveyed into the second stomach ; and yet, when there, great part of it continues in its spherical or oval form, still undigested, as viewed by him with his glasses ; and consequently must be conveyed further, before it be thoroughly digested, and the particles broken ; yet this he supposes is reconveyed upwards through both the stomachs, and is emitted by its mouth ; and he forms his judgment from his observation, that the bee, when working, and finishing the cells, nips with its teeth the wax, where it is too thick, or wrong laid ; and has observed a motion of its tongue as it were smoothing or laying on more materials, which he thinks must be then discharged fi-om the stomach by its mouth. What makes me disagree from him in his opinion and observations, is from the remarks I have made, that the faeces of the bee discharged by the anus, after the farina is digested, is the true wax. We may with truth believe, that the farina, which is the male seed of all vegetables, consists of a spirit or moving principle, floating in a sweet oil, surrounded by an exterior coat or shell, in which is that monade that impregnates the grain or fruit, and makes it prolific ; that on separation or digestion, this spirit and sweet oil becomes the nourish- ment of the bee ; which spirit is of the same nature with the animalcules in se- mine masculino of animals, and becomes the animal spirits in the bee and other animals ; and perhaps the true honey is the sweet oil included in the farina : and as all vegetables abound with these vegetable vivifying atoms, since from many every bud is capable of increasing each species, so the true honey breaking through its shell by great heat, occasions those honey-dews observed in hot weather on the leaves and flowers of most vegetables ; which is no more than an exudation from the leaves and blossoms of these vessels that break with the heat; VOL. XLVI.] PHILOSOPHICAL TKANSACTIONS. 81 besides those that appear on the apices of flowers, which afterwards impregnates the fruit. Of this inner substance of the farina, diluted with water, after digestion, is formed the bouillee and jelly, which the bees discharge upward by the mouth, into the cells, to nourish the young bees till they become nymphae ; while the husk, or outer coat is discharged by the anus, and becomes the genuine wax. I have frequently, when bees have been swarming, had them alight on my hands andcloaths; and many, at different times, have discharged their faeces on them : this I have taken off, and found it of the consistence of warm wax, with the same glutinous adhering quality, not crumbling like the farina. I have also distinguished it by the smell to be wax; but it had a heavier stronger smell, as it was fresh and warm from the bee. What further confirmed me in this fact, was from my observation of the bees when working up their comb in a glass hive; where I have constantly seen (and must believe it impossible not to be observed by so accurate an observer as M.' Reaumur) that several bees, soon after one another, have by hasty steps, walked along a comb then forming, for the length of 2 or 3 cells, bending their tails to the comb, and striking it with a wriggling motion from side to side, in a zigzag way ; which I was convinced was discharging their faeces, or the wax, against the border of the cells, as they ran along, and repeated it as long as they had any to discharge, and then quit it ; which is the reason why the outer border of the cells is so thick and strong : immediately afterwards, other bees came along the cells, and with their fore feet raised up the borders like paste, and thinning it, while other bees were ripping off with their teeth, and pruning away any irregular excrescences, so as to make the divisions of the cells vastly thinner than the borders or edges, which were always thick and strong, from the discharging the faeces or wax upon them. M. Reaumur has very justly observed that, besides the 3 transparent smooth eyes which the bee has placed in a triangle between the antennae on the top of its head, the bee has also on each side of its head and eye, or rather a multitude of eyes, formed by a number of distinct lenses each surrounded with short hairs, which are confirmed to be eyes, both from Swammerdam, and his own experi- ments to determine it ; and that, notwithstanding these lenses are lined with a dark opaque substance, yet they assist so miich their vision, that when darkened by paint laid over them, the bees could not find their way to their hive, though at a small distance, but soared directly upwards ; nor could they find their way when the 3 smooth eyes were darkened. But there is one observation, which I don't find he has made, which may have de- termined the garden bees to make almost all their cells imperfect hexagons. The ob- servation is this ; that these opaque eyes on each side of the head, consist of many VOL. X. M 81 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. lenses, each of which is a perfect hexagon ; and the whole eye, when viewed in a microscope, appears exactly like a honeycomb : now as the eyes, composed of these hexagonal lenses, are in full view to the other bees, does it not seem that Providence has directed them so as to be a pattern set before them, for the bees to follow in forming their combs ? It is not also reasonable to believe, from the disproportion of the convexity between the 3 smooth transparent eyes, and the lenses of the dark, rough eyes, that they are appointed for different purposes ? Why may it not be thought that the lenses are great magnifiers to view things near at hand, and by many reflections to convey light into the dark of hives, where light is still necessary ; and that the 3 other eyes are to observe objects at a great distance, so as to conduct them abroad to fields at a distance, and back again to their hives ? I agree with M. Reaumur in the form and use of the fang or tromp of the working bee, and of the use of the mouth within the teeth of the bee ; so that it does not suck, but laps or licks with its rough fang or tromp, like a dog. But I have never observed the bee nipping or breaking open the apices of flowers, to let out the farina, when it is not fully blown or open ; but have often with pleasure observed the bee gathering the farina on its fang, by licking it off the apices, and laying it on the first pair of legs, which convey it to the second pair, and these lodge it on the pallet of the third pair, with surprizing briskness ; so that, by the time the second pair has lodged it on the third pair, the bee has gathered more, and lodged it on the fore legs ; so that all are in constant motion. From the curious observations made by M. Reaumur, on the structure and behaviour of the queen or mother bee, the drone or male bee, and the working or mule bee, which is of neither sex ; from the queen bee's being so exceedingly prolific, as to lay from 30 to 40000 eggs of working bees in a season ; besides the eggs of 800 male bees, and of 8 or 10 queen or mother bees ; and from the coldness of the male bee who so long resists the caresses of the queen or female bee ; and also from the indefatigable labour and economy of the working bee, to nourish the young bees, make up the combs, and lay in stores of farina and honey for winter ; I think very good reasons may be given why the queen should have a seraglio of some hundreds of male bees ; and why the working bee should destroy the males, when no longer necessary to impregnate the eggs of the mother bee. It is evident, from the economy of the garden bee, that Providence has ap- pointed that they should share their store with mankind, by making them so in- dustrious in every climate, as to provide, in tolerable seasons, a store of honey and wax, double of what is necessary for their subsistence during the winter, and of combs for the queen's laying her eggs in spring, before new work can be made. VOL. XLVI.J PHILOSOPHICAL TKANSACTIONS. 83 From the vast number of eggs which the queen lays in a season, it is absolutely necessary that she should have a great store of male sperm, to impregnate her eggs ; and as the eggs are not sensibly large in her body for 6 months after her coition with the males, who die, or are killed, in August, and she does not begin to lay from that time till February or March ; it is therefore necessary that she should have a great store of male sperm within her, to impregnate all the eggs she lays from that time, till June or July, when young drones or males are hatched, who are not designed for her use, but for the young queens, who go oft' with the swarms, or for the young queen who succeeds the old one in the old hive ; since the drones are great feeders, and no workers ; and are of no use, but to give a sufficient store of sperm to the mother bee ; as the work- ing bees have so many enemies to deprive them of their store, they cannot be maintained during the winter, even if their life should last so long ; and as it is probable that each male has but one act of coition with the queen, as they are so cold, and take so much caressing before they act, and, by M. Reaumur's observation, die soon after the act is over, when probably their whole store of sperm is exhausted in that act, as soon as the queen has got as much sperm lodged in the proper reservoir, as is sufficient to impregnate all her future eggs, the males are no longer of use ; and if those who have acted die, those who have not, being of no further use, are killed by the working bee, out of economy to save their winter store, when probably by nature they could live but few days more ; as we find the silk-worm moth dies soon after the eggs are laid, as well males as females. It seems therefore necessary that the queen should breed so many males as, by one act of coition from each, may impregnate all her eggSj and that the working bee should dispatch them, as soon as that is over, and a Store is lodged. There are 2 vessels described by Swammerdam in the mother- bee ; one of which is placed between the two lobes of the ovarium, which he supposes to be a bladder to contain air ; the other is a spherical vessel, seated close by the common duct, in which the eggs fall from the lobes of the ovarium, which he supposes is to ooze out a juice to moisten the eggs in their passage. I take one of thescj, but most probably the last, to be the reservoir and repository of the male sperm, wherein it is lodged from the act of coition, till the eggs are enlarged, and pass through the adjoining duct from the 1 lobes of the ovarium. Since the preservation and increase of bees are evidently beneficial to the pub- lic, I approve very much of M. Reaumur's instructions in driving bees from a full hive into an empty one, in case it can be done time enough to have new work, sufficient for the queen to lay her eggs in in spring ; since they can be fed at very little expence, if care be taken to keep them in a middle state of stupefaction, neither too hot nor cold, during the winter : but I approve nmch M 2 84 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750, more of his castrating or sharing the combs with the bees, by taking the combs best stored with honey, and leaving those having the nymphae and bee-bread; but think, in taking the combs, a safer and easier way may be taken, than he directs: his method is to stupefy the bees with smoke, to oblige them to croud together in the crown of the hive, and then turning up the hive, and cutting out the combs filled with honey. Now I think, that turning up the full hive, and setting an empty hive upon it, and driving the bees into it, is preferable to smoking; for then a very few bees will remain in the full hive, and those few may be stupefied, and the bees in the empty hive being put on a table, the combs may be taken out and selected at leisure, without hazard; and afterwards the empty hive may be turned up, and their old hive set over them, so that they will go up without scruple into their former hive, and repair their work, by making new combs: and if the queen had not quitted the old hive, as is often the case, then they would return to their queen, and the society would not be lost, as is sometimes the case, in driving into an empty hive. Further Experiments on Substances Resisting Putrefaction ; with Experiments on the Means of Hastening and Promoting it. By John Pringle, M. D., F. R. S. N° 496, p. 550. 1 . Decoctions of wormwood and of the bark, also infusions of camomile- flowers, and of snake-root, these preserved yolks of eggs, not only several days longer than water did alone, but also when a good quantity of sea-salt was added to it. Dr. P. likewise found that salt of hartshorn preserved this substance better than 4 times its weight of sea-salt. 2. Ox's gall was kept some time from putrefaction by small quantities of ley of Tartar, spirit of hartshorn, crude sal ammoniac, and the saline mixture, and still longer by a decoction of wormwood, infusions of camomile-flowers, and of snake- root; by solutions of myrrh, camphor, and salt of amber; all were separately mixed with gall, and found more antiseptic than sea salt; and seemingly in pro- portion to their effects on flesh. Only nitre failed; which, though 4 times stronger than sea salt in keeping flesh sweet, is inferior to it in preserving gall, and remarkably weaker than crude sal ammoniac: which again is somewhat less powerful than nitre in preserving flesh. The nitre was soon opened by the gall, and emitted a vast quantity of air, which rose as from a fermenting liquor: and when this happened, the gall began to putrify. But the saline mixture gene- rated no air, and opposed the putrefaction of gall more than it did that of flesh. 3. The last trial was with the serum of human blood, which was preserved by a decoction of the bark, and an infusion of snake-root, nor with less efficacy than flesh. But saffron and camphor were not here above a 4th part so antiseptic VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 85 as before ; whether it be that they are less preservative of this humour, or, as he suspects, that they were not well mixed. Nitre acted nearly with its full force, being about 4 times stronger than sea-salt; it generated some air, but much less than it did with the gall. No other humour was tried; but from these specimens, addal to the former experiments, we may conclude, that whatever is preservative of flesh, will be generally antiseptic, though perhaps not always with equal force. 4. Having already shown how putrid flesh might be sweetened, he concludes this part of his subject with a like trial on the yolk of an egg. A portion of this, being diluted with water, stood till it corrupted; when a few drops were put into a phial with 1 ounces of pure water, and about twice as many drops were mixed with a strong infusion of camomile-flowers. At first both phials had some degree of a putrid smell ; but being corked, and kept a few days near a fire, the mixture with plain water contracted a strong fetor, while the other smelled only of the flowers. Thus far he has related the experiments made with antiseptics; by which it ap- pears, that besides spirits, acids, and salts, we are possessed of many powerful resisters of putrefaction, endued with qualities of heating, cooling, volatility, astriction, and the like, which make some more adapted than others to particular indications. In some putrid cases, many proper antiseptics are already known: in others they are wanting. We are yet at a loss how to correct the sanies of a cancerous ulcer ; but from such a multitude of antiseptics, it is to be hoped some may be found at last adequate to that intention. It may be further remarked, -that as different distempers of the putrid kind require different antiseptics, so the same disease will not always yield to the same medicine. Thus the bark will fail in a gangrene, if the vessels are too full, or the blood sizy ; but if the vessels are relaxed, and the blood resolved or disposed to putrefaction, either from a bad habit, or the absorption of putrid matter, then is the bark a good specific. With the same caution are we to use it in wounds, viz. chiefly in cases of absorbed matter, which infects the humours, and induces a hectic fever. But when in- flammatory symptoms prevail, the same medicine increasing the tension of the fibres, and siziness of the blood, a state directly opposed to the other has such consequences as might be expected. By the success of the bark in so many putrid cases, it should appear that as- triction had no small share in the cure. And indeed the very nature of putre faction consists in a separation or disunion of the parts. But as there are other cases, in which astringency is less wanted, we may find in contrayerva-root, snake-root, camphor, and other substances, a highly antiseptic power, with little or none of the other quality. And since several of these medicines are also dia- phoretic, their operation is thereby rendered more successful. Dr. P. comes now to the last thing proposed, which is, to give an accotmt of '#5 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. some observations made on substances hastening or promoting putrefaction ; an inquiry not less useful than the former. For, setting aside the oftensive idea commonly annexed to the word, we must acknowledge putrefaction to be one of the instruments of nature, by which many great and curious changes are brought about. With regard to medicine, we know that neither animal nor vegetable substances can become aliment, without undergoing some degree of putrefaction. Many distempers proceed from a deficiency of this action. The crises of fevers seem to depend on it; and perhaps even animal heat, according to a late inge- nious theory.* But, in the prosecution of this subject, he had met with very few real septics; and found many substances, commonly accounted such, of a quite opposite na- ture. The most general means of accelerating putrefaction is by heat, moisture, and stagnating air; which being sufficiently known and ascertained, he passed over, without making any particular experiment on those heads. Lord Bacon, (vide Nat. Hist. cent. iv. exper. 330,) as well as some of the chemists, has hinted at a putrid fermentation, analogous to what is found in vegetables; and this hav- ing so near a connection with contagion. Dr. P. made the following experiment, for a further illustration of this matter. 5. In the yolk of an egg, already putrid, a small thread was dipped, and a small bit of this was cut oft' and put into a phial, with half of the yolk of a new- laid egg diluted with water. The other half, with as much water, was put into another phial, and both being corked, were set by the fire to putrefy. The result was, that the thread infected the fresh yolk, for the putrefaction was sooner perceived in the phial that contained it, than in the other. But this ex- periment was not repeated. In this manner the putrefaction of meat advances quicker in a confined than a free air ; for as the most putrid parts are also the most fugitive ; they incessantly issue from a corruptible substance, and disperse with the wind; but in a stagna- tion of air, they remain about the body; and by way of ferment excite it to corruption. 6. As for other septics, recited by authors. Dr. P. found none of them answer the purpose. The alkaline salts have been considered as the chief putrefiers. But this is disproved by experiments. Of the volatiles it may be indeed observed, that though they preserve from the common marks of putrefaction, with a force 4 times greater than that of sea-salt ; yet, in warm infusions, a small quantity of these salts will soften and resolve the fibres, more than water does by itself. They also hinder the coagulation of blood , and when taken by way of medicine, ♦ An Essay on the Cause of Animal Heat, by J. Stevenson, m. d. Vide Medical Essays, vol. y. — Orig. VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 87 thin and resolve it, but are not therefore septics. For so little do these salts putrefy, or even resolve the fibres, when applied dry, that he had kept, since the beginning of June last, notwithstanding the excessive heats, a small piece of flesh in a phial, preserved only with salt of hartshorn, at present perfectly sound, and firmer than when first salted. 7. From the specimens he had of the antiscorbutic plants, it is likewise probable that none of that tribe will prove septic. Horse-raddish, one of the most acrid, is a very powerful antiseptic. And though carrots, turnips, garlick, onions, celery, cabbage, and colewort, were tried, as alcalescents, they did not hasten, but somewhat retarded the putrefaction. 8. The case was different with such farinaceous vegetables as were examined, viz. white bread in infusion, decoctions of flour, barley, and oatmeal; for these did not at all retard putrefaction: but, after it was somewhat advanced, they checked it by turning sour. By a long digestion the acidity became considerable ; which, by conquering the putrescency of the flesh, and generating much air, did not ill represent the state of weak bowels, which convert bread, and the mildest grains, to such an acid, as prevents a due resolution and digestion of animal food.* g. He examined cantharides, dried vipers, and Russian castor, all animal sub- stances, and therefore most likely to prove septic. The flies were tried both with fresh beef, and with the serum of human blood: the vipers only with the former: but neither of them hastened putrefaction. And as for the castor, so far from promoting this process, that an infusion of 12 grs. opposed it more than the standard salt. 10. After finding no septics where they were most expected, he discovered some which seemed the least likely; viz. chalk, the testacea, and common salt. 20 grs. of crabs'-eyes prepared, were mixed with 6 drs. of ox's gall, and as much water, into another phial was put nothing but gall and water, in the same quan- tity with the former; and both being placed in the furnace, the putrefaction began much sooner where the powder was than in the other phial. He infused afterwards in the lamp furnace 30 grs. of prepared chalk, with the usual quantity of flesh and water; and observed, that the corruption not only began sooner, . but went higher by this mixture; nay, what had never happened before, that in a few days the flesh resolved into a perfect mucus. The experiment was repeated with the same effect ; which being so extraordinary, he suspected some corrosive substance had been mixed with the powder; but, for a trial, a lump of chalk * It is to be remarked that, in making this experiment. Dr. P. did not then attend to a fermenta- tion that ensued, and which was the cause of the acidity. This kind of fermentation between ammal and vegetable substances, being hitherto overlooked, is set forth in the next paper. — Orig. . 88 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. being pounded, 30 grs. of it proved fully as septic as the former. The same powder was compared with an equal quantity of salt of wormwood, and care was taken to shake both the mixtures alike: but after 3 days warm digestion, the salt had neither tainted nor softened the flesh, while the chalk had rotted and con- sumed that which was joined to it. Nor were the effects less of the testaceous powders of the dispensary. Egg-shells in water resisted putrefaction, and pre- served the meat longer firm than plain water.* 1 1 . To try whether the testacea would also dissolve vegetable substances, he infused them with barley and water, and compared this mixture with another of barley and water, without the testacea. After a long maceration by a fire, the plain water swelled the barley, became mucilaginous and sour; but that with the powder kept the grain to its natural size, though it softened it, made no muci- lage, and remained sweet. 1 1. Nothing could be more unexpected than to find sea-salt a hastener of pu- trefaction. But the fact is thus: 1 dr. of salt preserves 2 drs. of fresh beef, in 2 oz. of water, above 30 hours, uncorrupted, in a heat equal to that of the human body ; or, what amounts to the same, this quantity of salt keeps flesh about 20 hours longer sweet than pure water ; but ^ dr. of salt does not preserve it above 2 hours longer. This experiment has been already mentioned. Now he after- wards found, that 25 grs. have little or no antiseptic virtue; and that 10, or 15, or even 20 grs. manifestly both hasten and heighten the corruption. -f- It is moreover to be remarked, that in warm infusions with these smaller quantities, the salt, instead of hardening the flesh, as it does in a dry form, in brine, or even in solutions, such as our standard, it here softens and relaxes the texture of the meat, more than plain water, though much less than water with chalk, or the testaceous powders. Many inferences might be made from this experiment: but he only mentions one. Salt, the indispensable seasoner of animal food, has been supposed to act bv an antiseptic quality, correcting the too great tendency of meats to putrefac- tion. But, since it is never taken in aliment beyond the proportion of the cor- rupting quantities in these experiments, it would appear that salt is subservient to digestion, chiefly by a septic virtue; that is, by softening and resolving meats; an action very different from what is commonly believed.:}; * The trial was made with a coarse powder of this substance, but not repeated. — Grig. t The most putrefying quantity of salt, with this proportion of salt and water, is about 10 grs. —Grig. I According to later physiologists, salt in small quantities proves subsen'ient to digestion, by its stimulant action on the stomach; in the same manner as spices and other kinds of seasoning do. vol,. XLVI.] PHILOSOPHICAL TRANSACTIONS. 6Q On the late Dr. Hnlley's Demonstration of the Analogy of the Logarithmic Tangents to the Meridian Line, or Sum of the Secants. By Mr. John Robert- son* F.R.S. N"496, p. 559. Dr. Halley, in this tract, N" 219, Philos. Trans, seems to have had 2 points chiefly in view, first, to prove, that the divisions of the meridian line in a Mer- cator's chart, were analogous to the logarithmic tangents of the half-complements of the latitudes. 2dly. To find a rule by which the tables of meridional parts might be computed from Brigg's, or the common logarithmic tangents. The former of these the Doctor has clearly and elegantly proved, but lie has given rather too few steps to show as clearly the investigation of the latter. Article 1 . If the circumference of a circle be divided into any number of equal parts, by as many radii; and a line be drawn from the circumference cutting those radii, so that their parts intercepted between this line and the centre be in a continued decreasing geometric progression ; then will that intersecting line be a curve, called the proportional spiral, and will intersect those radii at equal angles. This will be evident, by supposing the radii so near to each other, that the inter- cepted parts of the spiral may be taken as right lines; for then there will be a series of similar triangles, each having an equal angle at the centre, and the sides about those angles proportional. 2. The same things still supposed: the parts of the circumference of the circle reckoned from any one point, may be taken as the logarithms of the ratios be- * John Robertson, f.r.s. the author of this paper, was born in the year 1712; and though he was at first placed out in a trade, yet he must soon have quitted it, as in the title of his first book, a Complete Treatise on Mensuration, in 1739, he is stiled teacher of the mathematics. In this line, as a private teacher, he continued several years, till in 1754 he was appointed master of the Royal Mathematical School in Christ's Hospital ; in which year also he published the first edition of his Elements of Navigation. The year following however he left Christ's Hospital, in consequence of an Admiralty appointment to be first master of the Royal Naval Academy at Portsmouth; soon after which, he published his treatise on mathematical instruments. In 1766, through the petty cabals of the second master, he was dismissed from his situation by the first lord of the Admiralty; on which he returned to London, where, in the latter part of that year, or early in the next, l)e was appointed clerk and librarian to the Royal Society; an employment which he respectably held to the time of his death, in Dec. 1776, at 64 years of age. Besides the three publications above-mentioned, which were all excellent of their kind, particu- larly the navigation, and have gone through numerous editions ; he had many ingenious papers in- serted in the Philos. Trans, from the 46th to the 60th volume. Mr. R. was a person of very honour- able character and conduct, being greatly respected by the more learned and best characters among the members of the Royal Society; on most occasions his opinions in the council were much regarded- and he had the honour to be one of the committee chosen to inspect and report on the government's powder magazine at Purfleet, concerning its damage and security from lightning. In his mode of teaching, and arranging the materials in his publications, he was remarkably neat and methodical • a habit which he probably in some measure acquired in imitation of his good friend and master Wm Jones, Esq. many of whose papers, on his demise, passed into the hands of Mr. Robertson which were afterwards sold by auction, along with the valuable library of the latter, after his death. VOL. X. N go PHILOSOPHICAL TRANSACTIONS. [aNNO 1730. tween the corresponding rays of the spiral. — For those rays are a series of terms in a continued geometric progression; and the parts of the circumference form a series of terms in arithmetic progression. Now the terms of the arithmetic series being taken as the exponents of the corresponding terms in the geometric series, there will be the same relation between each geometric term and its corre- lative, as between numbers and their logarithms. And hence the proportional spiral is also called the logarithmic spiral. 3. That proportional spiral, which intersects its radii at angles of 43 degrees, produces logarithms that are of Napier's kind. — For, if the ditterence betweeiv the first and second terms in the geometric series was indefinitely small, and the first division of the circumference was of the same magnitude; then may that part of the spiral, intercepted between the first and second radii, be taken as the diagonal of a square, two of whose sides are parts of those radii ; therefore the spiral which cuts its rays at angles of 45°, has a kind of logarithms belong- ing to it, so related to their corresponding numbers, that the smallest variation between the first and second terms in the geometric series, is equal to the loga- rithm of the second term, a cypher being taken for the logarithm of the first. But of this kind are the hyperbolical logarithms, or those first made by their inventor the Lord Napier: consequently the logarithms to that spiral which cuts its rays at angles of 43°, are of the Napierian kind. 4. The rhumb-lines on the globe arc analogous to the logarithmic spiral. — For every oblique rhumb cuts the meridian at equal angles; and it is a property in stereographic projections, that the lines in it intersecting each other, form angles equal to those which they represent on the sphere. Therefore a projection of the sphere being made on the plane of the equator, the meridians will become the radii of the equator, and the rhumbs intersecting them at equal angles, will become the proportional spiral. Hence, the arcs of the equator, or the differ- ences of longitude reckoned from the same meridian, are as the logarithms of those parts of the corresponding meridians, intercepted between the centre and rhumb-line. ) 5. A sea chart being constructed, in which the meridians are parallel to each other, and the lengths of the degrees of latitude increase in the same proportion as the meridional distances decrease on the globes, will constitute a Mercator's chart, in which, besides the positions of places having the same proportions to each other, as on the globes, the rhumb lines will be represented by right lines. — For none but right lines can cut at equal angles several parallel right lines. 6. The divisions of the meridi:m line on a Mercator's chart, are the same as a table of the differences of longitude answering to each minute, or small differ- ence of latitude on the rhumb line making angles of 45° with the meridians. — For, in such a chart, the parallels of latitude are equal to the equator, and are at right angles to the meridians; and therefore a rhumb of 45° cuts the meri- VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. Ql dians and parallels of latitudes at equal angles; consequently between the inter- section of any meridian and parallel, and a rhumb cutting them at 45°, there must be equal parts of the meridian and jjarallel intercepted; now, on tlie equa- tor, or parallels of latitude, are reckoned all the successive differences of longi- tudes; and on the meridians the successive meridional differences of latitudes, or the divisions of the nautical meridian; therefore on the rhumb of 43°, the suc- cessive differences of longitude are equal to the corresponding divisions of the nautical meridian. 7. The tangents of the angles which different rhumbs make with the meri- dians, are directly proportional to the differences of longitudes made on those rhumbs, when the meridional differences of latitudes are equal ; or, are recipro- cally proportional to unequal meridional differences of latitudes on those rhumbs, when the differences of longitudes are equal. — For the meridional difference of latitude, is to the difference of longitude, as radius is to the tangent of the angle of the course, or of the angle which the rhumb makes with the meridian. Therefore, when the meridional differences of latitudes are equal, the differences of longitudes are as the tangents of the courses ; but when the differences of longitudes are equal, the meridional differences of latitudes are reciprocally as the tangents of the courses. 8. The logarithmic tangents of the half-complements of the latitudes, are analogous to the lengthened degrees in the nautical meridian line, in a Mercator's chart. — For, in the stereographic projection of the sphere on the plane of the equator, the latitudes of places are projected by the half-tangents of the com- plements of those latitudes; which half-tangents are the rays of a proportional spiral. Now, if a series of successive latitudes be taken on any rhumb, the corresponding differences of longitudes will be logarithms to the rays of the spiral, or to the tangents of the half-complements of those latitudes; therefore the dif- ferences of longitudes are as the logarithmic tangents of the half-complements of the latitudes; but, art. 6, the lengthened degrees on the nautical meridian are as the differences of longitudes on the rhumb of 45°; consequently the loga- rithmic tangents of the half-complements of latitudes are as the lengthened de- grees on the nautical meridian. Corol. 1. When the angle between the rhumb line and the meridian is equal to 45°, then the longitudes of places on that rhumb are expressed by logarithms of Napier's kind; whose corresponding numbers are natural tangents of the half-complements of the latitudes to arcs expressed in parts of the radius. Carol. 2. Hence, to any two places on a rhumb of 45°, the difference of longitude, or the meridional difference of latitude, is equal to the difference of the Napierian logarithmic tangents of the half-com]jlements of the latitudes of those places, estimated in parts of the radius. Corol. 3. As there may be an indefinite variety of rhumbs, and therefore avS N 2 g2' PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. many different kinds of logarithms, consequently every species of logarithms has its peculiar rhumb, distinguishable by the angle it makes with the meridian : therefore, among these there are 2 kinds, to which the differences of longitudes are the differences of the logarithmic tangents of the half-complements of lati- tudes, estimated in minutes of a degree; one of them belonging to Napier's form of logarithmic tangents, and the other to Briggs's, or the common loga- rithmic tangents. 9. The common logarithmic tangents are a table of the differences of longi- tudes to every minute of latitude, on the rhumb line making angles with the meridians of 51° 38' Q". — For, let z represent the meridional difference of lati- tude between 2 places on the rhumb of 45"; or its equal, the difference between the logarithmic tangents of the half-complements of the latitudes of those places, estimated either in parts of the radius, or in minutes of a degree. Then, As the circumference in parts of the radius = 62831,853 &c : To the circum- ference in minutes of a degree = 2160O :: So is a meridional difference of lati- tude in parts of the radius = z : To a meridional difference of latitude in mi- nutes of a degree, = 0,34377468 &c. X z. ■ Whose corresponding rhumb is different from that which z belonged to; and the angle which this rhumb makes with the meridian, will be found by the fol- lowing analogy from art. 7- — As the meridional difference of latitude on one rhumb = 0,34377^68 &c. z : To the meridional difference of latitude on a rhumb of 45°, = z :: So is the natural tangent of the rhumb of 45°, = 10000 : To the natural tangent of the other rhumb, = 29088,821 &c. Which tangent answers to 71° l' 42"; and this is the angle that the rhumb line makes with the meridians, on which the differences of the logarithmic tan- gents of the half-complements of the latitudes, in Napier's form, are the true differences of longitudes estimated in sexagesimal parts of a degree. Now Na- pier's logarithms being to Briggs's, as 2,30258 &c. is to 1 ; therefore, 2,30258 &c. : 1 :: 29088,821 &c. : 12633,114 &c.; which is the tangent of 51° 38' Q"; and in this angle are the meridians intersected by that rhumb, on which the dif- ferences of Briggs's logarithmic tangents of the half-complements of the lati- tudes are the true differences of longitudes corresponding to those latitudes. 10. The difference between Briggs's logarithmic tangents of the half-comple- ments of the latitudes of any two places, is to the meridional difference of lati- tude in minutes between those places, in the constant ratio of 1263,3 Sec. to 1 ; or of 1 to 0,0007915704 &c. — For Briggs's logarithmic tangents are as the dif- ferences of longitudes on the rhumb (a) of 51° 38' Q"; whose natural tangent is 1263,3 &c. The nautical meridian is a scale of longitudes on the rhumb (b) of 45°, by art. 6, whose tangent being equal to the radius, may be expressed by unity. And the differences of longitude to equal differences of latitudes on different rhumbs, TOL. XLVI.] PHILOSOPHICAL TBANSACTIONS. 93 being to each other as the tangents of the angles those rhumbs make with the meridians. Tlierefore, as the tangent of a (51° 38' Q") = 1,2633 &c : To the tangent of b (45°) = 1,0000 : So is the difference of longitudes on a, or the ditt'erence between the logarithmic tangents of the half co-latitudes of two places : To the difference of longitudes on b, or the meridional difference of latitudes of those places. And hence arise the rules which are given in nautical works, for finding the meridional parts by a table of common logarithmic tangents. This curious discovery of Dr. Halley's, joined to that excellent thought of his, of delineating the lines, showing the variation of the compass, on the nautical chart, are some of the very few useful additions made to the art of navigation within the last 130 years; for if, beside these, we except the labours of that in- genious artist Mr. Richard Norwood, who improved the art by adding to it the manner of sailing in a current, and "by finding the measure of a degree on a great circle, the theory of navigation will be found nearly in the same state in which it was left by that eminent mathematician Mr, Edward Wright; who, about the year l600, published the principles on which the true nautical art is founded; and showed, what does not appear to have been known before, how to estimate a ship's true place at sea, as well in longitude as in latitude, by the use of a table of meridional parts, first made by himself, and constructed by the constant addition of the secants, and which differs almost insensibly from such a table made on Dr. Halley's principles, contained in the preceding articles. Mr. R. concludes this discourse with an article which, though it be somewhat foreign to the preceding subject, yet, as it was discovered while he was contem- plating some part of it, and perhaps is not exhibited in the same view by others, it is annexed in this place; which is, to demonstrate this common logarithmic property, that the fluxion of a number divided by that number, is equal to the fluxion of the Napierian logarithm of that number. Let BEG be a logarithmic spiral, cutting its ^^ rays at angles of 45°: then, if ae be taken as a » •■ ''/V M number, bc will be its Napierian or hyperbolic \ -^ ^f.// \ '■■ logarithm. Also, let CD express the fluxion of tVc'"' ''X/^ / \ \ the logarithm bc ; then the corresponding \/r' / I ■ fiiixion of the number ae, will be represented ^^v\ / I '■ by FG, or its equal fe; as the angles feg and Bv""*"^ I "• FGE are equal. Now, ac : cd :: ae : (ef =) fg. \ ^ tcT'^D Therefore cd = — X ab. And if ab be taken \ | • AE \ I ■• as the unit or term from whence the numbers \l .". _ En. ' I'F begin: then CD = — . Q. E. d. >v": *' AE ^V 45 17 40 30 39 38 39 11 39 46 94 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. Observation of the Total Lunar Eclipse, June I9, 1750, N.s. at Witlemberg. By G. M. Base, Prof, of Philos. N° 496, p. 570. The end of the shadow, by corrected time, as follows : 11^ 40™ 37' End according to Mr. Bose himself. . . according to a friend. . . by the projection of a friend. , , by the corrected calendar of Leipsic. . . by the Connoisance des temps. . . by the Ephemeris of Manfredi. On the Heat of the Weather at Tooling, in July and September last. [1750] By the Rev. Henry Miles, F.R.S., D.D. N° 496, p. 571. The morning at 4, July 11, had nothing remarkable : at 2 p.m. the heavens mostly clear, and no indications of a storm ; the barometer having fallen but -pf-j- inch since 4 a.m. it then stood at 30, 20. the thermometer at &7-L, and before .3 p.m. at 88^, which is the hottest temperature of the air he ever knew. At 4 p.m. was very distant thunder; soon after it came a little nearer, and was one continued murmur, without any perceivable intermission for great part of an hour : the lightning accompanying it, not much. The wind was nearly s.w. and dark clouds passed by on each side till they united in the n. forming one of the blackest clouds he ever saw, over the city, as near as he could guess. They had not one drop of rain, nor did there fall either rain or hail for near 3 miles to the N. of the place towards London : a few hail-stones it seems fell in some parts ofClapham. The barometer fell little, and the thermometer no more than usual at that time of the evening. Mr. Canton writes that his thermometer in Spital square (of the same construction, and kept too in the open air) fell no less than 17 degrees. At 4 a.m. Sept. 2, the wind being easterly, and blowing strong, accompanied with several short showers of rain, the barometer being at 29.97, the thermo- meter abroad stood at 61 : a degree of heat exceeding any he had taken notice of during the whole summer at that time of the morning. On the Hot JVeather in JulyllbO, dated Norwich July 23. By Mr. fVm. Jrderon, F.R.S. N°49(), p. 573. For 12 days past, the weather was at Norwich the most excessive ever known. The beginning of this heat was on July 8th ; when, though the whole day was cloudy, the ground was so uncommonly hot, that Mr. A. could not bear to walk on it long together without much uneasiness ; and many others were sensible of VOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. (JS the same inconvenience. On the 11th, which was the hottest day of all, the thermometer in the sun's rays stood 1 1° above the heat of human blood ; and in the shade only 8° below it. The distance between freezing and the heat of hu- man blood being divided into 100 parts. An inch of tallow, -i\ of an inch in diameter, liquefied in the sun in less than 30 minutes. A piece of resin, -^ of an inch in diameter, became so soft as to be liable to take any impression in the same time. About 3 o'clock in the afternoon, when the sky is clear, is the hottest part of the day ; but clouds mostly came on about that time on these days. Several horses dropped down dead under their masters, overcome by this violeqt heat. j4 Total Eclipse of the Moon, observed Dec. 2, 1750, in the Morning in the Strand, London, about 5' of Time West of St. PauCs, and 27' West of the Roijal Observatory at Greenwich. By Dr. Bevis and Mr. James Short, F. R. S. N° 496, p. 575. A sensible penumbra (Dec. 1) at 16" 32'" O^ The eclipse judged to begin at ]6 36 50 Total immersion at 17 36 5 The moon begins to emerge 1 9 14 33 The moon was now got so low, and day-light so far advanced, that no more phases could be observed with any degree of certainty. These observations were made with a reflecting telescope, that magnified 40 times, and a refracting tele- scope, which magnified 1 2 times , and the times were the same through these 2 telescopes ; for the air was exceedingly clear, and the shadow well defined, the penumbra being scarcely sensible. Here follows a computation, made from Dr. Halley's tables, by Mr. John Catlin, of Guy's hospital ; and sent to Mr. Short the day before the eclipse. Beginning of the moon's eclipse. (Dec. 1)... 16** 44™ 31* Immersion at 17 42 45 Emersion at I9 20 37 End at 20 18 51 Hence it appears, that the eclipse began about 8 minutes sooner than the com putation from Dr. Halley's tables gave it ; but the computation which Mr. Brent made and published some time before the eclipse happened, was within a minute of the time observed ; and this exactness he imputes to his leaving out 3 of the 7 equations of the moon, published by Sir Isaac Newton in his theory of the moon. An Account of some Experiments, made by Benjamin Robins, Esq. F.R.S., Mr. Samuel Da Costa, and several other Gentlemen, in order lo discover the Height 96 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750, lo luhich Rockets may be made to ascend, and to what Distance their Light may he seen. By Mr. John Ellicott, F.R.S. N° 496, p. 578. Soon after the exhibition of the fire-works in the Green Park, on occasion of the late peace, Mr. Robins communicated to the Society an account of the height to which several of the rockets there fired were observed to rise. In this account, after having given a short description of the instrument with which the heights were measured, he observes, that the customary height to which the single or honorary rockets, as they are styled, ascended, was about 465 yards : that 3 of them rose to about 550 yards ; and the greatest height of any of those fired in the grand girandole was about 60O yards. He further observed, that supposing rockets are made to ascend 600 yards, or more than a third of a mile, it follows, that if their light be sufficiently strong, and the air not hazy, they may be seen in a level country at above 50 miles distance ; and that, from the nature of the composition, and the usual imperfect manner of forming them, he was of opi- nion that rockets were capable of being greatly improved, and made to reach much greater distances. Mr. Robins not having been able to obtain any certain account to what dis- tance any of these rockets were actually seen, and considering the great use that might be made of rockets in determining the position of distant places, and in giving signals for naval and military purposes, he resolved to order some rockets to be fired at an appointed time, and to desire some of his friends to look out for them at several very distant places. The places fixed on for this purpose, were, Godmarsham in Kent, about 50 miles distant from London ; Beacon-hill on Tiptery-heath in Essex, at about 40 miles ; and Barkway, on the borders of Hert- fordshire, about 3S miles from London. Mr. Robins accordingly ordered some rockets to be made by a person many years employed in the royal Laboratory at Woolwich ; to which some gentlemen, who had been informed of Mr. Robins's intentions, added some others of their own making. The 27th of September, 17^9, at 8 in the evening, was the time ap- pointed for the firing of them ; but, through the negligence of the engineer, they were not let off till above half an hour after the time agreed on. There were in all a dozen rockets fired from London-field at Hackney ; and the heights were measured by Mr. Canton, Mr. Robins being present, at the distance of about 1200 yards from the post from whence the rockets were fired. The great- est part of them did not rise to above 400 yards ; one to about 500, and one to 600 yards nearly. A letter received the next day from the Rev. Dr. Mason, of Trinity college, Cambridge, who had undertaken to look out for them from Barkway on the borders of Hertfordshire, informed, that he plainly saw 4 rise, turn, and spread; XXTL. XLVI.] PHILOSOPHICAI, TRANSACTIONS, QJ He judged they rose about one degree above the horizon, and that their lights were strong enough to have been seen much farther. From Essex Mr. R. was informed, that the persons on Tiptery-heath saw 8 or Q rockets very distinctly, at about half an hour past 8 ; and greatly to the east- ward of these 5 or 6 more. The gentlemen from Godmarsham in Kent having waited till above half an hour past 8, without being able to discern any rockets, they fired half a dozen ; which, from the bearings of the places, were most pro- bably those seen to the eastward by the persons on Tiptery-heath ; and if the situations, as laid down in the common maps are to be depended on, at about 35 miles distance. The engineer being of opinion that he could make some rockets, of the same size as the former, that should rise much higher, Mr. Robins directed him to make half a dozen. These last were fired the 12th of October following, from the same place, and in general they rose nearly to the same heights with the foregoing ; excepting one which was observed to rise 6qo yards. The evening proved very hazy, which rendered it impossible for them to be seen to any consi- derable distance. Among some rockets fired in the last spring, there were two made by Mr. da Costa of about 3-l inches diameter, which were observed to rise, the one to about 833, the other to QIS yards. At a second trial, made some time after, there was one made by Mr. da Costa, of 4 inches diameter, which rose to 1 1 QO yards. The last trial was made the latter end of April 1750, when 28 rockets were fired in all, made by different persons, and of different sizes, from 1^ inch diameter to 4 inches ; the most remarkable of each size were as follows : one of 1 -^ inch rose to 743 yards ; one of 2 inches to 659 ; one of 2^ inches to 880 ; another of the same size, which rose to IO71 ; one of 3 inches to 1254 ; one of 34. inches to llOQ; and one of 2 inches, which, after having risen to near 700 yards, turned, and fell very near the ground before it went out. These were all made by Mr. da Costa. Besides these, there was one of the rockets of 2-l inches in diameter, which rose to 784 yards, and another made by Mr. Banks of the same size to 833. After allowing for possible errors, it still appears certain that several of these rockets rose to 1000 yards, one to 1 100, and another to 1200 yards, or double of any of those fired in the Green Park. Several Papers concerning a new Semi -metal, called Platina. Communicated to the R.S. by Mr. Wm. IVatson* F.R.S. N° 496, p. 584. * As this appears to have been the first printed account of this new metal, it has been judged to be due to the memory of those who communicated it to reprint it nearly in the original form. VOL. X. O gS^ PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. Extract of a Letter from William Brownrigg, M.D., F. R. S. to Wm. Watson, F.R.S. Dated Whitehaven, Dec. 5, 1750. p. 584. Dr. B. here communicates an account of a semi-metal called platina di Pinto ; which, so far as he knew, had not been taken notice of by any writer on mine- rals. Presuming therefore that the subject was new, he requested the favour to have this account laid before the r. s. The experiments related were several of them made by a friend, whose exactness in performing them, and veracity in relating them, he could rely on : however, for greater certainty, he should him- self repeat them. Memoirs of a Semi-metal called Platina di Pinto, found in the Spanish West Indies, p. 585. Though the history of minerals, and other fossil substances, has been dili- gently cultivated, especially by the moderns ; yet it must be acknowledged, that among the vast variety of bodies which are the objects of that science, there still remains room for new inquiries. Gold is usually esteemed the most ponderous of bodies; and yet he had seen, in the possession of the late professor Gravesande, a metalline substance, brought from the East Indies, that was specifically heavier than gold, by at least a 20th part.* Mercury, next to gold, is commonly said to be the heaviest body; yet mercury was greatly exceeded in specific gravity by a semi-metal -|- brought from the West Indies, of which he had presented specimens to the r. s. This semi-metal seems more particularly to deserve attention, as it is endued with some very singular qualities, which plainly demonstrate that certain general theorems, though long established, and universally received by the metallurgist, yet do not hold true in all cases, and ought not to be admitted into their arts, without proper limitations and restrictions. For instance, that gold and silver may be purified from all heterogeneous substances by coppellation, is a proposition that all assayers and refiners have long thought true and undeniable; yet this proposition ought not to be received by those artificers, without an exception to the semi-metal here treated of; since, like those nobler metals, it resists the power of fire, and the destructive force of lead in that operation. This semi-metal was first presented to him (Dr. Brownrigg) about Q years pre- • This metalline substance, in the possession of Gravesande, though brought from the East In- dies, (indirectly from commercial intercourse by the Spaniards with South America) was probably the very metal here treated of, viz. platina (now called platinum), of which the specific gravity in its purest state is 23.000, while that of gold is only 19.3. ■\ Wrongly termed a semi-metal, but at that time taken for such, as the means of reducing it to i reguline and malleable state were then unknown. rOL. XLVI.] PHILOSOPHICAL TRANSACTIONS. 99 ceding the above date, by Mr. Charles Wood, a skilful and inquisitive metallur- gist, who met with it in Jamaica, whither it had been brought from Carthagena in New Spain. And the same gentleman had gi'atified Dr. B.'s curiosity, by making further inquiries concerning this body. It is found in considerable quan- tities in the Spanish West Indies, and is there known by the name of platina di Pinto. The Spaniards probably call it platina, from the resemblance in colour that it bears to silver. It is bright and shining, and of a uniform texture ; it takes a fine polish, and is not subject to tarnish or rust ; it is extremely hard and compact ; but like Bath-metal, or cast iron, brittle, and cannot be extended under the hammer. * ./ The Spaniards do not dig it in the form of ore, but find it in dust, or small grains, as were herewith presented to the r.s. Whether they gather it in a pretty pure state, as brought to us, or wash it, like gold-dust, from among sand, and other lighter substances, was to him unknown : however, it is seldom col- lected perfectly pure ; since, among several parcels of it that he had seen, he constantly observed a large mixture of a shining black sand, such as is found on the shores of Virginia and Jamaica, which is a rich iron ore, and answers to the magnet. It has also usually mixed with it some few shining particles of a golden colour, which seem to be a substance of a different nature. It is very probable that there is great plenty of this semi-metal in the Spanish West Indies ; since trinkets made of it are there very common. A gentleman of Jamaica bought 5 lb. of it at Carthagena for less than its vreight of silver ; and it was formerly sold for a much lower price. When exposed by itself to the fire, either in grains, or in larger pieces, it is of extreme difficult fusion; and has been kept for 2 hours in an air-furnace, in a heat that would run down cast iron in 15 minutes: which great heat it endured without being melted or wasted ; neither could it be brought to fuse in this heat, by adding to it borax, and other saline fluxes. But the Spaniards have a way of melting it down, either alone, or by means of some flux ; and cast it into sword- hilts, buckles, snufi'-boxes, and Other utensils. When exposed to a proper degree of fire, with lead, silver, gold, copper, or tin, it readily melts, and incorporates with these metals ; rendering the mixture, like itself, extremely hard and brittle. Having been melted in an assay-furnace, on a test with lead, and with it ex- posed to a great fire for 3 hours, till all the lead was wrought off, the platina was afterwards found remaining at the bottom of the test, without having suffered any alteration or diminution by this operation. A piece of platina was put into strong and pure aqua fortis, and with it placed • Not in its native or crude state j but when properly purified, it may be extended under the hammer. o a 100 PHILOSOPHICAL TRANSACTIONS. [aNNO 1750. in a sand-heat for 12 hours: the platina, when taken out of the aqua fortis, was found of the same weight as when put into it ; being in nowise dissolved or cor- roded by that menstruum. It had been reported, that this semi-metal was specifically heavier than gold ; * but having weighed several pieces of it hydrostatically in a nice assay-balance, he found one of these pieces was to that of water exactly as 1 5 to 1 . Another piece, that seemed to be cast very open and porous, he found in gravity to water only as 13.91 to 1 : though this last-mentioned piece, could it have endured the ham- mer as well as gold, might probably have been reduced to a considerably greater degree of solidity than that of the first-mentioned specimen. For the purest gold is seldom found, after fusion, to come up to its true specific weight, till it has been brought up to its greatest degree of solidity under the hammer. He also weighed an equal mixture of gold and platina, which he found nearly as ponderous as gold itself; the specific weight of this mixture being to that of water as 1 9 to 1 . It had been reported, that the Spaniards had sometimes been tempted to adul- terate gold with platina, as the mixture could not be distinguished from true gold by all the ordinary trials : but the gold thus adulterated was, on a nicer examination, found hard and brittle, and could not be separated from the platina, and rendered ductile and pure, either by cementation, or by the more ordinary operations with lead and antimony. In order therefore to prevent this fraud, the king of Spain commanded that the mines of platina should be stopped up ; so that this semi-metal is now much scarcer than formerly. From the foregoing account it appears, that no known body approaches nearer to the nature of gold, in its most essential properties of fixedness and solidity, than the semi-metal here treated of; and that it also bears a great resemblance to gold in other particulars. Some alchemists have thought that gold differed from other metals in nothing so much as in its specific gravity ; and that, if they could obtain a body that had the specific weight of gold, they could easily give it all the other qualities of that metal. Let them try their art on this body; which, if it can be made as ductile as gold, will not easily be distinguished from gold itself. On the whole, this semi-metal seems a very singular body, that merits an exacter inquiry into its nature than has yet been made; since it is not altogether improbable that, like the magnet, iron, antimony, mercury, and other metallic substances, it may be endowed with some peculiar qualities, that may render it of singular use and importance to mankind. ♦When thoroughly purified, it is specifically heavier than gold, weighing 23.000 j whereas the specific gravity of gold is only 19.3. . , VOL. XLVI.]^ PHILOSOPHICAL TKANSACTIONS. 101 The 3d communication on this interesting subject is from Mr. Watson, who says, that this platina di Pinto is likewise called in America, Juan Blanco. It is not mentioned in any author he has met with, except Don Antonio d'Ulloa, who, in the History of his Voyage to South America, vol. ii. b. 6, ch. 10, which he has here extracted, and translated from the Spanish, when giving an account of the gold and silver mines in the province of Quito, and of the various methods of separating these metals from other substances, with which they are combined, says, that " in the territory of Choco there are gold mines, in which that metal is so disguised and enveloped with other mineral substances, juices, and stones, that, for their separation from the gold, they are obliged to use quick- silver. Sometimes they find mineral substances, which, from their being mixed with platina, they chuse to neglect. This platina is a stone (piedra) of such re- sistance, that it is not easily broken by a blow on an anvil. It is not subdued by calcination; and it is very difficult to extract the metal it contains even with much labour and expence." In the before-mentioned work, ch. 11, the same author, when speaking of the remaining works of the Indians of old, says, " the specula wrought out of stones, which are found in the places of worship of the Indians, are of 2 kinds, in regard to the matter of which they are made : one of these is called piedra de Inga, the other piedra de Gallinazo. The first of these is smooth, of a leaden colour, and not transparent ; they are usually found wrought of a circular figure: one of the surfaces is plain, and as smooth as though it were made of a kind of crystal ; the other surface is oval, or rather somewhat spherical, and not so much burnished as the plain one. Though they vary in their size, they are commonly from 3 to 4 inches in diameter; but he has seen one that was a foot and a half in diameter. Its principal surface was concave, and. much augmented the size of objects, for its polish was in as great perfection as though it had been worked by a dextrous artist in these times." " This stone has certain veins, or hair-like appearances, on its surface ; by which it is rendered less fit for a speculum, and is apt to break in these veins in receiving any blow. Many are persuaded, or at least suspect, that the matter of these is a cast composition ; and though there are some appearances of this being so, they are not sufficiently convincing. In this country there are gullies (que- bradas) where the mineral of them is found rough, and from whence some are always taken ; but these are not now wrought for those purposes f &c. as before ; p being in this case = sum of all the quantities «, P, y, S, &c. a = the sum of all their squares ; r = the sum of their cubes, &c. &c. Carol. A. — Since a, P, y, S, &c. are the roots of the equation, z" — bz*"' + ex"-* — DS""', &c. = 0 ; it follows, that, if b, c, d, e, &c. be given , the sum of those roots (p) ; the sum of their squares (q), and the sum of their cubes (r) &c. will also be given from the foregoing equations : whence will be had p = B a = + PB — 2c R = — PC + OB + 3d S = -|- PD — GC + RB — 4e T = — PE + an — RC + SB + 5f &c. &c. where the law of continuation is obvious. These values are the same with those given (without demonstration) by Sir Isaac Newton, in his Universal Arithmetic, for finding when some of the roots of an equation are impossible. Pfob. 1. — To find a series expressing the value of (1 + ?)- X (1 + ~Y X (1 + '-)' X (1 + jV, &c. By putting u = (1 + ^)"', w = (1 + ^)", &c.; and proceeding as in the last problem ; there will be had - = !^ X (1 - - 4- "' - 4 &c.) VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 131 &C. &C. Whence, making suming A + Bar + cr' + dt^ + E'^*> &c. to express the series sought, the several values of a, b, c, d, &c. will be exhibited by the very equations brought out in the resolution of the preceding problem. F", On the Use of the Bark in the Small-pox. By Geo. Bayly, M. D., p. 27. An account is here given of a gentlewoman of a fat, corpulent habit, who at the age of 73 had the small-pox in the natural way. During the first 3 days of the eruption the patient went on well ; but on the 8th day the pustules were at a stand ; they sunk in, and her life was despaired of. At this period Dr. B. di- rected blisters to be applied to the legs, and prescribed 3SS. of the powder of Peruvian bark, and a few grains of serpent. Virginiana every 3 hours ; by the use of which the pustules were made to rise and brought to a maturation. The bark and serpentaria were afterwards given in decoction. By a long continuance of these medicines (with the use of the lancet once, and with the help of occa- sional purges) the patient was restored to health. To this is subjoined the case of a healthy young man, who, in July 1 746, had the small-pox by inoculation. The eruption came on at the right time ; but, 3 or 4 days after, in dressing the incisions, 3 or 4 purple spots were observed about them, which occasioned Dr. B.'s being called in. The pustules, which were very numerous, were here and there livid, and in the arms and thighs of a dark colour, tending towards a mortification. He immediately prescribed 353. of bark to be given, and repeated once in 3 hours ; which was accordingly done for 1 1 days successively ; during which time he took 47 doses of bark, viz. in all, 3 oz. wanting -i- a dr. VI. A Method of v\,aking Artificial Magnets without the Use of, and yet far su- perior to, any Natural ones. By John Canton,* M. A., andF. R. S. p. 31. Procure a dozen bars ; 6 of soft steel, each 3 inches long, one quarter of an * Mr. Canton, a very ingenious natural pliilosopher, was born at Stroud, in Gloucestershire, 17I8; where his father, a broadcloth weaver, at a proper age put him to learn his own business. But young C. having at school acquired some knowledge in the elementary branches of mathematics, and a taste for philosophical subjects, he spent his time by stealth in reading books of that kind. His singular habits and early acquirements procured him the notice of several learned men, and among others the Rev. Dr. Henry Miles of Tooting, who prevailed on the father to permit the young man to come up to London to try his fortune there ; which he accordingly did in 1737, when S2 132 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751, inch broad, and Vt of an inch thick, with two pieces of iron, each half the length of one of the bars, but of the same breadth and thickness ; and 6 of hard steel, each 54- inches long, half an inch broad, and -J^ of an inch thick, with 2 pieces of iron of half the length, but the whole breadth and thickness of one of the hard bars : and let all the bars be marked with a line quite round them at one end. Then take an iron poker and tongs, or 2 bars of iron, fig. 2, pi. 3, the larger they are, and the longer they have been used, the better ; and fixing the poker upright between the knees, hold to it near the top one of the soft bars, having its marked end downward, by a piece of sewing silk, which must be pulled tight with the left hand, that the bar may not slide : then grasping the tongs with the right hand a little below the middle, and holding them nearly in a ver- tical position, let the bar be stroked by the lower end, from the bottom to the top, about 10 times on each side, which will give it a magnetic power sufficient to lift a small key at the marked end : which end, if the bar was suspended on a point, would turn toward the north, and is therefore called the north pole, and the unmarked end is, for the same reason, called the south pole of the bar. Four of the soft bars being impregnated after this manner, lay the other two, (fig. 3) parallel to each other, at the distance of about one-fourth of an inch, between the two pieces of iron belonging to them, a north and a south pole against each piece of iron : then take 2 of the 4 bars already made magnetical, he articled himself for i years as an assistant to Mr. Watkins, master of the academy in Spital-square : on the expiration of which period, in 1742, he was taken into partnership with that gentleman, whom he afterwards succeeded in the school, and there continued till the time of his death, in 1772, In the 54th year of his age. Mr. C. being a man of very genteel and modest behaviour, he gained the respect and acquaintance of the most eminent philosophers of his time ; with whom he ardently entered on the pursuit and improvements of the then fashionable topics in philosophy ; as electricity, magnetism, lightning, &c. in many branches of which he made considerable improvements and discoveries. In 17-1-9 he was engaged, with his friend Mr. Robins, and Mr. Ellicot, in making experiments on the height to which rockets can ascend, and the distance at which their light can be seen. His paper above printed, on making artificial magnets, procured his election as a fellow of the a. s. and the present of their gold medal : and the same year he was complimented with the degree of m. a. by the university of Aberdeen. And in 1751 he was chosen one of the council of the r. s. an honour which was twice repeated afterwards. In 1752 he, first of any person in England, verified Dr. Franklin's hypothesis of the similarity of electricity and lightning, by drawing electric fire from the clouds during a thunder storm. Next year also he communicated to the r. s. another discovery of this kind, viz. the negative and positive states of electricity among the clouds; a discovery also just made in America by Dr. Franklin. In 1 762 Mr. C. communicated his curious experiments on the compressibility of water; for which he was a 2d time honoured with ttie r. s.'s gold medal. Num- berless other ingenious papers were written by Mr. C. and published in the Philos. Trans, as well as several other periodical works : a particular account of which, and many other circumstances in Mr. Canton's life, may be seen in Dr. Hutton's Dictionary of Philosophy and Mathematics, VOL. XLVir.] PHILOSOPHICAL TRANSACTIONS. J 33 and place them together, so as to make a double bar in thickness, the north pole ol" one even with the south pole of the other ; and the remaining 2 being put to these, one on each side, so as to have 2 north and 2 south poles together, separate tlie north from the south poles at one end by a large pin, and place them perpendicularly with that end downward, on the middle of one of the parallel bars, the 2 north poles towards its south, and the 2 south poles to- wards its north end : slide them backward and forward 3 or 4 times the whole length of the bar, and removing them from the middle of this, place them on the middle of the. other bar as before directed, and go over that in the same man- ner ; then turn both the bars the other side upward, and repeat the former ope- ration : this being done, take the 2 from between the pieces of iron, and placing the 2 outermost of the touching bars in their stead, let the other 2 be the outer most of the 4 to touch these with : and this process being repeated till each pair of bars have been touched 3 or 4 times over, which will give them a considerable magnetic power, put the half dozen together after the manner of the 4 (fig. 4,) and touch with them 2 pair of the hard bars, placed between their irons at the distance of about half an inch from each other : then lay the soft bars aside ; and with the 4 hard ones let the other 2 be impregnated (fig. 5) holding the touching bars apart at the lower end near -^ of an inch, to which distance let them be separated after they are set on the parallel bar, and brought together again before they are taken off: this being observed, proceed according to the method described above, till each pair has been touched 2 or 3 times over. But as this vertical way of touching a bar will not give it quite so much of the mag- netic virtue as it will receive, let each pair be now touched once or twice over, in their parallel position between the irons (fig. 6) with 2 of the bars held hori- zontally, or nearly so, by drawing at the same time the north of one from the middle over the south end, and the south of the other from the middle over the north end of a parallel bar ; then bringing them to the middle again without touching the parallel bar, give 3 or 4 of these horizontal strokes to each side. The horizontal touch, after the vertical, will make the bars as strong as they can possibly be made : as appears by their not receiving any additional streno-th, ' when the vertical touch is given by a greater number of bars, and the horizontal by those of a superior magnetic power. This whole process may be gone through in about half an hour, and each of the larger bars, if well hardened,* may be * The smith's manner of hardening steel, whom Mr. C. chiefly employed, and whose bars have constantly proved better than any he could meet with beside, is as follows : having cut a sufficient quantity of the leather of old shoes into very small pieces, he provides an iron pan, a little exceedino- the length of a bar, wide enough to l.iy two side by side without touching each other or the pan, and at least an inch deep. This pan he nearly half fills with the bits of leather, on which he lays the two bars, having fastened to the end of each a small wire to take them out by : he then quite fills 134 PHILOSOPHICAX TRANSACTIONS. [aNNO 1751. made to lift 28 Troy ounces, and sometimes more. And when these bars are thus impregnated, they will give to a hard bar of the same size, its full virtue ia less than 2 minutes : and therefore will answer all the purposes of magnetism in navigation and experimental philosophy, much better than the loadstone, which is well known not to have sufficient power to impregnate hard_ bars. The half dozen being put into a case (fig. 7) in such a manner, as that 2 poles of the same denomination nmy not be together, and their irons with them as one bar, they will retain the virtue they have received . but if their power should, by making experiments, be ever so far impaired, it may be restored without any foreign assistance in a few minutes. And if, out of curiosity, a much larger set of bars should be required, these will communicate to them a sufficient power to proceed with, and they may in a short time, by the same method, be brought to their full strength. f^lf. An Aurora Borealis observed at the Hague, Feb. 27, N. S. 1750. By Peter Gabre, J. K. D. Phys. Astron. et Math. From the Latin, p. 3Q. This very luminous aurora borealis was in the form of an iris, the extremities of which extended from the eastern horizon to the west, and its top towards the south near the zenith, rising near 80° above the horizon. Its breadth at the vertex was about 2°, but narrowed to cusps at the two extremities. The middle of the arc emitted a strong white light ; but weaker towards the sides. Fill. Further Observations on the Cancer Major. By Mr. Peter CoUitison, F.R.S.y p. 40. That the cancer major, and all species of crabs, cast their shells, is certain ; but at what season of the year, or how frequently, is not exactly to be deter- mined ; but it is believed to be annually at the beginning of the summer, sooner or later, according to the greater or less strength of the crab. There is in the under part of the shell a suture in the form of a crescent, which retains a part of the shell of the same figure. At the time of casting the old shell, this suture opens, and leaves a space sufficient for drawing out the whole body ; after which the thorax drops its breast-plate, and then the legs quit their crustaceous coverings. The carcase now is left inveloped with a soft skin like wet parchment. In this helpless state the crab is incapable of moving, but it lies at the bottom of the sea, between the rocks, till its new shell ac- quires a sufficient hardness and consistence, fit for its defence, and its limbs grow strong enough to bear its weight, and carry it about, to perform its ne- the pan with the leather, and places it on a gentle flat fire, covering and surrounding it with char- coal. The pan being brought to somewhat more than a red heat, he keeps it so about half an hour, and then suddenly quenches the bars in a large quantity of cold water. — Orig. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 185 cessary functions; while the old shell is left in two parts, that which covered the body in one part, and that which covered the breast and legs, in another. It happens sometimes that the shell hardens prematurely. In this case the poor animal is made a prisoner, being so cramped, that he cannot disengage himself from his hiding-place, till found by the fishermen, and set at liberty by moving the stones from about him. It is surprizing to consider how a creature can live long confined without any aliment, and yet increase in its dimensions But that the crab will subsist without a sensible decay in the fishermen's pen- pots,* for the space of some months, is very certain. The more healthy and thriving a crab is, the more frequently he casts his sheH. But, if he becomes sickly and wasting, the old shell remains on him, till such time as he recovers strength and vigour to cast it. When the fishermen take a crab, that is not in a good condition, they return it into the sea, and often mark it on the back with a sharp-pointed iron, or top of a knife ; and this mark not only remains on the old shell, as long as it continues on, but is found in the same manner impressed or serrated on the new shell ; a very strange and surprizihg phenomenon, but I am assured it is fact. If a crab receives a small wound in the very extremity of the claw, he generally bleeds to death, or pines away by slow and insensible leaking of the vital moisture. But if he receives any considerable wound or hurt, that gives him pain, he instantly throws off the offending member, and all is safe, and a new limb soon succeeds to make it again perfect. The leg is always thrown off at the same joint ; the blood is stopped by the membrane, that lines that articulation, contracting itself in the form of a purse. If a crab be brought near the fire, he throws off the legs, which feel a pain- ful heat. In like manner if a crab be thrown into hot water, he casts off all his legs together. For which reason, when they are to be boiled, they put them into the pot in cold water, and let it warm very slowly, till the creature gradually die. The lobster casts its shell much in the same manner as the river crayfish, which are a species of fi-esh water lobsters. JX. An Account of the Right Hon. Horace fValpole,'\- clraivn up by Himself. Dated April 1750. p. 43. Mr. W. here states, that Lord Barrington having heard of his complaint, • These are cages in the sea, made with willow-twigs to keep the crabs in. — Orig. + Brother to the celebrated statesman Sir Robert Walpole, and uncle to the late Horace Walpole (Lord Orford). He died in 1737. From his earliest years (observes Mr. Coxe in his Memoirs of VOL. X. s 4 136 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. sent him the 5th vol. of the Edinb. Medical Essays, containing Dr. Whytt's account of the good effect which the taking of soap and limewater had had in cases similar to his; with ingenious reflections and directions relating to that cruel disease, and the remedy for it. He read them with great satisfaction, and would have immediately fallen into that method, but his relations, touched with the fatal effects, which Dr. Jurin's lixivium* had had on the late Lord Orford, would not suffer him to follow his own inclinations. But while he had a severe fit upon him, he was visited by the Earl of Morton, who, on hearing what was his disorder, gave him an account of the powerful benefit and entire cure, which Mr. Summers had found in voiding the stone, that had tormented him for many years, by adding lime-water to the soap, which he had taken for some time without any success. This example, by the encouragement of Mr. Graham, his apothecary, fixed his resolution to follow that method; and accordingly before he left the town, he often perused Dr. Whytt's Essay relating to the stone. In March 1 747-8, he began at first with taking every day -i^ oz. of Alicant soap, made up into pills with the syrup of marshmallows, and drank upon it about a pint of lime-water made of oyster-shells ; mixing a spoonful of milk with it, and drinking a spoon- ful after it, to take away the nauseousness of the tastes. On the road as he went into the country in May 1 748, he had a most severe fit at Newport, making bloody water, with frequent interruptions at short in- tervals, attended with violent pains, which continued on him to such a degree, that he could not endure the horses to go more than a foot-pace for about 70 miles, till he came home. After his arrival there he was tolerably well for some days; but the least motion in a coach, or even in walking, brought the dis- order upon him. He was always entirely easy when he lay in bed, but was ob- liged, when he got up, to take his couch ; and could not venture to move fitjm thence but on necessary occasions. In the mean time he continued to take the soap and lime-water, which by degrees he increased so far, as to take at different Sir Robert Walpole, vol. i. p. IS4) he had been trained to business, under Stanhope, in Spain ; under Carleton, when chancellor of the exchequer, and secretary of state ; under Townshend, at the con- gress of Gertruydenberg, and during the negociation for the Barrier Treaty in 1710. At the acces- sion of George I., he was appointed secretary to Lord Townshend, and afterwards secretary to the treasury; and, as envoy to the states general, had conducted with great skill and ability the compli- cated negociations which took place at the Hague in 1715 and 17l6. In 1722 he was deputed as en- voy to the Hague, which post he filled with great credit and dignity, and was particularly noticed by George 1. as a man of business and address. * In the medical practice of the preseiit day neither the lixivium here mentioned, nor lime- water (both which, but particularly the first of the two, possess a causticity which proves hurtful to the stomach,) are prescribed in calciJous affections j but in their stead the so called soda-water, in which the alkaline salt is rendered mild by super-saturation with the carbonic acid, (fixed air,) in which state it does not injure the stomach, and may be safely continued a great length of time. VOL. XLVII.J PHILOSOPHICAL TRANSACTIONS. 137 times 1 oz, of soap, and 3 pints of lime-water, every day, observing a very re- gular diet. After some months he found himself extremely easy in his ordinary motions ; but he never ventured to walk far, nor go at all in a wheel-carriage, keeping himself as quiet as he could, till he should be obliged to go to par- liament. Just before he left the country, Mr. Ranby made him a visit; and though he had felt no pain nor symptom of his disease for some time, he advised him not to hazard going to town by any means, unless it were in a litter. However, having caused an easy voiture to be made, he undertook the journey in it the 20th of November 1748, which was regulated by the horses going no faster than a gentle walk, and only 20 miles a day. The cold weather, and the tediousness of creeping so slow, made the coachman sometimes fall into a trot, which he perceived, but finding no inconvenience, did not check his pace. The set stages were observed only the last 2 days, and particularly the last day the coachman drove from Harlow to Whitechapel as full a trot as the horses could well go at any time ; and he felt not the least disorder. He took a chair at Whitechapel, and all that winter made use of nothing else, and continued extremely well'; but, about 2 months after his coming to town, he found some small uneasiness in making water, and in 2 or 3 days he voided with his urine something of a flat shape about the size of a silver penny, covered with a soft white mucus, which, when it was dry, was plainly of a stony substance ; and after that had never been troubled with the least symptom of that cruel disorder -. And he found himself so well in the country last year, that, contrary to the advice of all his friends, he undertook in his coach a journey to Chatsworth in Derbyshire from his house in the countr}', at least l6o miles, to pay a visit to the Duke of De- vonshire, the horses going as round a trot as they could conveniently, according to the road; and the last 10 or rather 15 miles, from Hardwicke to Chatsworth» a most rugged and rocky way, they neither spared themselves nor the horses. The great shocks on the stones broke the springs of the coach, but gave him not the least uneasiness, and he had ever after continued, with respect to his former disorder, as well as ever he was in his life ; but he had now and then voided, after he had sat a great while in the House of Commons, some re gravel. X. Extract of the Observations maae in Italy, by the j4bbt! Nollet, F. R. S. on the Grotta de Cam. Translated from the French by Thomas Stack, M. D. F. R. S., p. 48. This celebrated grotto is described in numerous books of travels, &c. Dogs exposed to the gas emitted from this cavern are thrown into a state of asphyxia, from which, however, they soon recover on being brought into the open air. VOL. X. T 138 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. XL A Letter from the Rev. Patrick Murdocke, F. R. S. concerning the Mean Motion of the Moon's Apogee, to the Rev. Dr. Robert Smith, Master of Trin. Coll. Camb. p. 62. A warm dispute arose lately at Paris between M. de BufFon and M. Clairaut ; the latter pretending that the Newtonian law of attraction is inconsistent, with the motion of the moon's apogee ; and that its quantity ought not to be expressed by - of the distance, but by two, or perhaps more, terms of a series, as \ •\- — ; which new doctrine M. Clairaut had got inserted in the memoirs of the Aca- demy, and M. de BufFon had followed him close with another memoir, confuting it. At first it was impossible to judge of the validity of M. Clairaut's reasoning, because he kept his calculus a profound secret. But an absurd consequence of his new law of attraction occurred as soon as M. de BuiFon mentioned the thing, that, " if we should put the attraction, expressed by his two terms, of an assumed quantity g, and resolve the equation, there would necessarily arise 1. different values of the distance x, for the same attractive force." Suspecting therefore, that some error must have slipt into M. Clairaut's reasonings (as he himself afterwards found there had), Mr. M. tried whether, by an arithmetical calculation from Sir Isaac Newton's propositions only, the motion in question might not be accounted for. By Mr. Walmesley's ingenious treatise on the same subject, it appears that however M. Clairaut's hypothesis is given up, yet a notion still prevails as if Sir Isaac Newton's propositions, con- cerning the motion of the apsides were mere mathematical fictions, not applicable to nature. The following calculation however of Mr. M. shows the contrary. Of the mean Motion of the Moons Apogee, according to Sir Isaac Newton. The rule given by Sir Isaac Newton, in the Qth section of his first book, is to this purpose : 1. That, supposing the common law of attraction, and that a central body t attracts the body p, fig. 8, pi. 3, revolving round it in an orbit nearly circular, with a force as unity ; if to this be added a constant force, whose ratio to the former is expressed by c ; then the angular velocity of the body p, in an immove- able plane, will be to its angular velocity, reckoned from the apsis of its orbit, 1 -I- c in the subdublicate ratio of 1 -f- c to 1 -j- 4 c, or as \/ :^—-r ^'^ unity. And there- fore, if a represent any arc described by the revolving body in an immoveable plane, then a X V' will be the corresponding arc in its orbit, reckoned from the apsis. And their difference a x {s/ £ — - — 1), willbethe regress of the apsis. But if the force of the central body t be diminished by some constant VOL. XLVII.] VHILOSOPHICAL TRANSACTIONS. ISQ force as c, then the sign of c is changed in these expressions ; and the direct motion of the apsis will be a X (1 — V^TZl — )• 2. And hence, if some foreign variable force, added to, or subtracted from, the central force of attraction, produce a given motion of the apsis, retrograde or direct ; it is easy to find a constant force as c, which should produce the same motion. 3. Let s represent the sun, at an immense distance, t the earth, (supposed, for the present, at rest) p the moon's place in her orbit adbc, in which c, d, are the quadratures, a, b, the syzygies : then if pk, parallel to ab, and cutting tc in K, be produced till kl is double of pk ; and lm parallel to pt meet ab pro- duced in M ; LM and mt will represent the disturbing forces of the sun, by which the moon is urged in the directions pt, mt. See Princip. lib. i. prop. 66, and lib. iii. prop. 25, 26. And if tr be made perpendicular to lm, the force mt shall be resolved into two forces as rt and mr ; of which the latter, mr, taken from LM, reduces the disturbing force, in the direction pt, to their difference lr. 4. Put now pt (= lm) =: 1 ; pk, the sine of the arc PC =s: and then tm (= PL = 3s): MR :: 1 : .«; that is, MR = 3*^, and lr, the disturbing force in the direction pt, is as 1 — 3*^. When cp, the moon's distance from the quadra- ture, is an arc of 35° 15' 52", in which case 1 — 33* = O, / and r coincide ; and the disturbing force vanishing, the line of the apses becomes stationary. But if the moon's distance from her quadrature be still greater, as at v, then jaj exceeds (*x; and their difference xj is a force represented by — (1 — 3j^), acting in the di- rection ttt. This force, at the syzygies, is double of to. 5. Hence, and from § 1, it follows; that c being the sun's disturbing force in the direction ct, at the quadrature ; at any other point, as p, it will be + c X (1 — Ss"^)- And that writing for c the variable quantity c- x (1 — 3i^), and A for the fluxion of the arc cp, the fluent of a X V ^-—: ~ f,\ will ecive 1 + c X ( 1 — 3«') ° the motions of the apsis. 6. The quantity c being , } gf-° ^ of the earth's mean attractive force at the moon ; by computing as above, it will be found, that while the moon moves from c to p, through an arc of 35° 15' 52", the total regress of the apsis is to the arc cp, as .005404 {= n) to unity ; and that the sum of its direct motions, while the moon moves from p to a, is to the arc j&A, as .0105707 (= n) to unity. It will be found likewise, by the inverse operation hinted in § 2, that putting k — .00362552, and k = .OO69611 ; + k and — k are forces, which acting constantly, the one from c to p, the other from p to a, would produce the same motions of the apsis. 7. The quantities h and k might have been found, pretty near the truth, only T 2 ■ • 140 PHILOSOPHICAL TRANSACTIONS, [aNNO 1751. by summing the ordinates 1 Z. R? or 1 — 3s\ on the arc A : in which case we should have had k = c X .648869 = .00370g'25, and k = c X 1.24018 = .006939 : and the motions thence computed would not have been much dif- ferent from their just quantity. This however is mentioned, not as if the me- thod itself were sufficiently exact ; but to show that if hereafter, in cases where the limits of the forces are incomparably narrower, we shall, instead of summing the momenta, make use of a mean force determined in a like manner, there is no sensible error to be apprehended. 8. Hitherto we have considered the body t, round which p revolves, as qui- escent ; and it is thus that authors have always considered it : though the case in nature, to which they meant to apply Sir Isaac Newton's rule, is widely different. The earth and moon revolve about their common centre of gravity; their dis tances from which being inversely as their masses, and the forces, by which either is attracted by the other, as also the forces of the sun to disturb their motions, being in the same ratio; it follows that the earth, in her motion round the common centre of gravity, will suffer disturbances every way similar to those of the moon. And the whole motion of the apsis of the moon's orbit, resulting from the two disturbing forces, will be nearly the double of what either of them could produce separately, round a fixed centre. 9. To determine this, we may conceive the earth as revolving in an orbit al- ready in motion from the sun's disturbing force on the moon; the retrograde motion of the orbit, while the earth moves from c to p, being n X cp; and the direct motion, for the rest of the quadrant, being n X />a ; hence it will follow, that the disturbing force, = k, affects the earth's motion through an arc of her orbit equal to cp X (1 -f- w); and the force — k acts through the arc pA X (1 -f n). And the motions of the apsis being in the same ratios, if r be the regress of the apsis of the moon's orbit (determined as in ^ 6) and p its progress ; the regress of the apsis of the earth's orbit will be r X (1 + ")> and its direct motion, J!j X (1 — n). That is, the whole motions of the apsis, resulting from the sun's action on the earth and moon together, will be (r =) r x (2 + n), and {p =) p X (2 — n); and the motions to be ascribed to either arc, r X (1 4- i-n), and /> X (1 — ^n). — Now p, found as above, being 2082'''.9 and N = .0105707, p is 4143". 8. And the same way, R = 1375".7- whose differ- ence p — R multiplied by 4, that is, 4 X 2768" = IIO72" = 3° 4' 32", is the direct motion of the apsis in a revolution. First correction for the moons variation. Fig. Q. — 10. In the foregoing cal- culation, it is supposed, that the moon's orbit is nearly circular, more nearly indeed than it possibly can be, even abstracting from its excentricity. For though the moon had been projected with a direction and force to make her describe a circle round the earth, as eol, the action of the sun would have changed this VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 141 orbit into an oval, as oadbc; whose greatest diameter, passing through the qua- dratures CD, is to the least, as 70Vt to 69^. The reason and determination of which we have in Princip. lib. iii, prop. 26, 28. 11. That this action of the sun, and the figure resulting from it, must lessen the mean motion of the a{X)gee, is easily shown. For let p be the moon's place in her orbit, w hen the apsis is stationary ; and eol the circle of her mean motion, cutting the orbit very near tne octant o, and pt in 0; then the accele- rating forces of the earth at p and o, being inversely as the squares of pt and ot, and the sun's disturbing force at the points p, 0, being in the simple direct ratio of the same lines; ot being given, the ratio of the sun's disturbing force at the point p, to the earth's accelerating force at the same point, that is, the quantity c in the theorem, will be as the cube of the distance pt; and, a fortiori, in every point of the orbit, from the quadrature c to p, will exceed the mean force at o, and its effect in producing a retrograde motion of the apsis will be greater. For the remaining part of the quadrant, where the motion of the apsis is direct, the force c is indeed greater than its mean quantity from p to o; but, through the whole octant oa, it is continually decreasing as the cube of the dis- tance from T ; hence, on the whole, that force, and its effect, from p to a, fall short of their mean quantities at o. Seeing therefore the direct motion is dimi- nished, and the retrograde increased; their difference, that is, the direct motion in the quadrant cpa will be diminished. But this mean motion will be diminished somewhat also from the inequable description of the areas (in prop. 26, lib. iii) ; on which account, the cubes of the distance pt must be every where increased, or diminished, in the duplicate ratio of the moments of time in which a given small angle is described, to the mean moment at the octant.* 12. By computing from these principles, it will be found: 1. That the angle CTP, which was of 35° 15' 52* in the circle, will, ift the oval orbit, be dimi- nished to 34° 43' 34". 2. That the ratio of the mean of the cubes of the moon's distances in the arc cp, to the cube of the mean distance, will be ex- pressed by 1.0239] 6 {= g), and the like ratio, in the arc pa, by .9852467 (= h). 3. Multiplying therefore the forces k and — k, found in ^6, hy g and • To express the distance pt by « the sine of the angle ctp, in an ellipsis not very eccentric; from any point p draw pk an ordinate to the axis cd, and meeting the circumscribed circle in m; draw likewise m/' perpendicular to tp produced. Then putting to = 1, ta = d, ■ ' = ii« !i'i\m 'ji»iiw (Siswtma mofl )yn.\/-\ l62 PHILOSOPHICAL TRANSACTIONS. [aNNO 175 J. ture round the neck : the fore-feet of these are five-fingered, with nails, like the common seal. Their size, as to the utmost growth of an adult, is also very different. That before described, was 7^- feet in length ; and, being very young, had scarcely any teeth at all. This in town is but about 3 feet long, is very thick in proportion, and has a well-grown set of teeth ; which, in a great measure, shows this to be about its full growth. The manati is also a phoca, and is one of those species which grows to a prodigious size. The great skin, in the museum, is that of a manati ; which seems to agree with the other species of this family, in every es- sential part, except broad bifid webs, instead of webbed feet : and Peter Martyr gives an account of one of these, which was 35 feet long, and 12 thick. The docility of this seal in town is, with reason, much admired, as a thing unusual and strange to us ; but it appears, from Dr. Charleton, that in his time it was not uncommon for the seamen and fishers to catch some of these creatures sleeping, on the coasts of Cornwall and the Isle of Wight, and bring them to be so tame, as to get money by showing them, and their performances : and he adds, that the people of the former place call the larger kinds about that coast soils, and the smaller seals. But the story told by the above author Martyr, of that great manati, shows how capable these creatures are of being rendered very familiar ; and how susceptible of impressions, though they really seem as unfit for any kind of education as any other whatever. This author describes the manati very fully; and then tells this remarkable story: " A governor, in the province of Nicaragua, had a young manati, which was brought to him, to be put into the lake Guanaibo, which was near his house ; where he was kept during 26 years, and was usually fed with bread, and such- like fragments of victuals, as people often feed fish with in a fish-pond. He be- came so familiar, by being daily visited and fed by the family, that he was said to excel even the dolphins, so much celebrated by the ancients for their docility and tameness. The domestics of this governor named him Matto ; and at whatever time of the day they called him by that time, he came out of the lake, took victuals out of their hands, crawled up to the house to feed, and played with the servants and children; and sometimes 10 persons together would mount upon his back, whom he carried with great ease and safety cross the lake." All that is here mentioned of the docility of this manati, does not much sur- pass that of this seal in town. He answers to the call of his keeper, and is ob- servant of his commands ; takes meat from his hand, crawls out of the water, and stretches at full length, when he is bid ; and when ordered returns into the water ; and in short stretches out his neck to kiss his keeper, as often and as long as required. These are marks of a tractableness, which one could hardly expect from animals, whose mien and aspect promise little, and indeed whose VOL. XLVII."! PHILOSOPHICAL TRANSACTIONS. 1 63 place of abode, being for the most part inaccessible, prevent their being fami- liarized to any commerce with men, except by mere chance. The teeth are very well preserved in the skin of the manati in the museum : they are l6 in the upper, and 14 in the under jaw; and of these, 4 are between the canine teeth of the upper, and 2 between those of the under jaw. They are all conical from the gums ; the canine teeth are 1 in each jaw ; being an inch and half long each, and of the same form with the rest ; and they all bend a little backwards by a small curve in themselves. Nor have the very back teeth of all the least resemblance to the molares of other animals. The walrus or mors, is another species of phoca, and differs very little in shape and parts from the other species of this genus ; except that the 2 canine teeth of the upper jaw are of a prodigious size, like the great teeth of an elephant. There are some species of this genus of the phoca, which never grow to above a foot long ; and there are of all sizes at full growth from these to the manati and walrus. The skins of every species have short hair, and their colours are variegated from the straw-colour and yellow to the deepest brown and black. They are sometimes regularly brindled, sometimes curiously spotted ; sometimes in brown clouds on a yellow ground, like that of a pied horse ; and sometime* the brown or black occupies the greater part of the skin, having less of the yel- low : and in short even those of the same species are as variously spotted or clouded as the hounds in the same pack ; and it is probable, that in unfrequented islands and countries, other species of this tribe are yet undiscovered. But it must be observed, that where no other difference, but the variegation of the colour, appears among them, that is, in their size, proportion, teeth, or extre- mities, they are no more to be accounted different species, than cows having va- rious changes in the distribution of the clouds or spots on their skins. In the first chapter of the second book of Lord Anson's Voyage, is described an animal under the name of the sea-lion. This history may be applicable to other species of phocae ; and by this description, as well as the figures exhibited in the book, what are counted sea-lions, are manatis. Linneus ranks this genus of animals with those of his 2d order of quadrupeds : and indeed with great propriety, however injudicious it may lately have been thought : for though none of this tribe can use the posterior extremities to raise themselves up, or stand upon them, as on legs and feet; yet they swim and guide themselves in the water with them ; for which they claim the title of pal- mipedes, or webbed feet ; for they have no similarity with fins. If it be objected, that these animals would come more naturally under his class of amphibia ; we may assert, that he had 2 very good motives for ranking them Y 2 l64 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751, with quadi-upeds. First, he had our great Ray for his director, who has him- self done the same thing: and, secondly, he found, that though these creatures are really amphibious, yet the commanding characters, by which he has, with great sagacity, distinguished his classes, prevail here to give them a place rather among the quadrupeds than the amphibia. This great naturalist divides the animal kingdom into 6 classes, and each class into 6 orders. Each order is again divided into different genera, and each genus again has its different species. The phoca then is the 6th genus under the 2d order of the quadrupedia ; which order is that he calls ferae.* M. de la Condamine, in the account of his voyage down the River of the Amazons, describes an animal, which doubtless is a species of the phoca. See figs. II, 12, 13, pi. 3. XVI. Of an Iliac Passion, from a Palsy of the large Intestines. Communicated to Dr. de Castro, F. R. S. Translated from the Latin, by Tho. Stack, M. D., F. R. S. p. 123. A merchant, aged 70, who had been accustomed to hardships from his in- fancy, was, for the last 6 years, subject to rheumatic pains ; but considering his disorder as the effect of old age, he rejected all medical advice. In these cir- cumstances it happened that he was suddenly set upon by a party of soldiers, who with severe threatenings turned him out of his house, and took possession of it : which so terrified him, that he was seized with a violent belly-ach ; and his agony so overpowered him, that he fell on the ground half dead, and at the same time voided blood by the anus. Afterwards he was much subject to the gripes all the ensuing winter, which he took no care of. During this time he suffered much from costiveness, till March 1747, when he was seized with severe pains about the navel ; and though he had clysters of several sorts given him, not one of them could be made to pass. He was feverish and thirsty, with a white moist tongue, and could not sleep. He was blooded as much as he could well bear ; and the blood did not appear in- flammatory. He was treated with laxative medicines, antiphlogistic fomenta- tions, to ease the gripings, and give a free passage ; but nothing took effect for 7 days together. On the 8th he began to break wind, retain the clysters, discharge some little faeces, and to sleep, though not quietly; and on the Qth to make turbid urine. But these promising appearances were but of short duration ; for on the 1 1 th his belly was so bloated, that he seemed tympanitic ; and an acute pain, which he • Dr. P. here refers to the tenth edition of the Systema Naturae of Linneus. VOL. XLVII.] VHXLOSOPHICAL TRANSACTIONS. J 65 had in the hypogastric region, darted up towards the midriff on the right side : and now the mucus of the intestines came away with the clysters. He had bad sweats, and made foul urine, without sefliment. On the 15th a consultation was held ; and as his thirst and fever were abated, and the medicines hitherto prescribed for opening a passage, and taking down the swelling, of the belly, which seemed ready to burst, had proved ineffectual, it was agreed to make him swallow 6 oz. of crude quicksilver, with oil of sweet almonds, and syrup of violets ; and soon after to throw in several purging clvsters. In 9 hours a passage was opened, and he voided much black liquid excrement, without the least grain of quicksilver. A little after that, he vomited much ; and in what he threw up there plainly appeared excrements, and globules of mercury. This was soon followed by thirst, a little slow fever, very troublesome gripings, no sleep, red high-coloured thick urine, in very small quantities, breaking of wind without any ease, vomiting of every thing he took, great weakness, and partial sweats in the forehead and breast. Under these symptoms he languished to the 20th day, and then died. The appearances, on dissection, were these: the omentum was consumed; and the colon was inflamed in several places, and so distended with wind, that it nearly filled the whole abdominal cavity. Its ligaments or bands were so tho- roughly effaced, that there was not the least sign of them remaining. The caecum was so stretched, as to occupy the whole capacity of the pelvis ; and that part of it, which is touched by the thick gut, was gangrened, and perforated with a small opening. Having cleared it of the excrements, there were no inter- nal rugae at the insertion of the ileum, nor any traces of the valve of the colon, or of its braces, to be observed. For it was quite smooth on the inside, as well as the colon, by the destruction of the cellules, which it has in a natural state. The quicksilver was dispersed all over the cavity of the abdomen, in such quan- tities, that it was easy to perceive, that none had been discharged by stool. Every thing else contained within both the cavities, was in its natural condition. XVII- On the Variation of the Magnetic Needle. By Peter Wargtnlin,* Sec. of the Royal j^cad. of Sciences in Sweden. BVom the Latin, p. 126. Dr. Halley suspected that there was some correspondence between the aurora borealis and the magnetic needle. And Celsius and Hiorter found by experi- ments that the needle was greatly disturbed, and unsteady, whenever the north- * Peter Wargentin was a Swedish mathematician, but chiefly distinguished as an astronomer, and particularly for his tables for computing the eclipses of Jupiter's satellites, which have been much used by astronomers. He was born in 1717, and died at the observatory at Stockholm in 1783, at 6()' years of age. \66 PHILOSOPHICAL TRANSACTIONS., [aNNO 1751. em lights rose to the zenith or passed southward, so as that the declination seemed to follow the motion of the light, and in a very few minutes of time would sometimes vary 3 or 4 degrees. M. Wargentin has also, by observations in Feb. 1730, like as Graham, Celsius, and others, observed before, found that there is a diurnal variation of the needle backward and forward : so as that from 7 in the morning till 2 afternoon, the needle declined more and more to the west by -f or -}- part of a degree ; after which it gradually returned again, so as by 8 at night to be nearly the same as it was at 8 in the morning. After this it is nearly at rest during the rest of the night, except some small motion to the west about midnight. And this diurnal variation never fails, but is constant and almost regular, unless when it is impeded by the northern lights. This he observed constantly from the 1st of February to the 15 th, on which last day an aurora borealis appeared, and deranged the needle so, as in 10 minutes time, about 10 at night, it shifted 20' to the west, and in another ten minutes returned thirty-seven minutes to the east. But on the lights disappearing, the needle settled at rest. And thus it continued in its regular diurnal vibrations, till Feb. 28, when it was again disturbed by another appearance of the northern lights, so as to cause the needle to vibrate irregularly between 6° 50' and 9° l' of west variation. And on the 2d of April, from a like cause, it differed from itself little less than 5°, shifting irregularly and frequently backward and forward, be- tween 4° 56' and Q° 55'. Xf^IlL Abstract of a Letter, dated May 2, 1750, from Mr. Freeman at Naples, relating to the Ruins of Herculaneum.* p. 131. About 7 or 8 years ago, the discovery of Herculaneum was much spoken of, which was reported to have been swallowed up by a violent eruption of Mount Vesuvius, according to the last accounts, in the first year of the reign of Titus, 79 years after Christ. The situation of this city is at the foot of Vesuvius near the sea, and just at one end of the village of Portici, the summer residence of the king of Naples ; and probably a great part of the city is under the said village. You are first conducted down a narrow passage, scarcely wide enough for 2 persons to pass ; and in a gradual slope, to the depth of about 65 feet perpen- dicular. Here is shown a great part of the ancient theatre, a building in the form of a horse-shoe. That part where the spectators sat, is visible, and consists of 18 rows of broad stone seats, one above another, in a semicircular form. At proper distances within the circuit of the seats, through the whole range, from bottom to top, are little narrow flights of steps, by which the spectators might come to, or go from, their seats commodiously, without crouding. These steps * See some former accounU of these ruins, vol. viii, p. 435 — 138, vol. ix, p 36'.' of these Abridg- ments. TOL. XLVII.^ PHILOSOPHICAL TRANSACTIONS. idjfl or stairs also lead up, in a straight line, to a sort of gallery, several feet wide, which ranges all round the outside of the theatre, and is called the precinct ; above which there are other stairs, which lead to a second. By this precinct it is judged, that the theatre, with the orchestra, must be about 52 or 53 feet diameter. Going round the theatre, are seen several large square pilasters, equally distant from each other ; and which supported the whole edifice. These pilasters are of a thin compact red brick, adorned with marble cornices. The pavement of this theatre must have been very beautiful, by the different coloured marble, that has been taken out of it, and some that remain. In short, by the broken pieces of cornices, mouldings, and carved work, and the many fragments of pillars, &c. which have been found within and without the theatre, it appears to have been a most magnificent edifice. There are 2 principal gates to the theatre, with inscriptions on the architraves, which are taken out, and placed in the king's palace, among the other curiosities. There is another opening, distant from that which leads to the theatre, by which they have made a way into some houses. Here they seem to have dug infinitely more than about the theatre ; for one may ramble, as in a labyrinth, for at least half a mile. Among the things that have been dug out of either of the two places, are many parts of broken horses, with part of a triumphal car or chariot, all of gilt bronze ; and which, they say, was placed over one of the gates of the theatre. Two equestrian statues, which were found on each side of one of the said gates, and they suppose fronting a street that led to the theatre. Those, they say, were erected in honour of the 2 Balbis, father and son, who were bene- factors to the Herculaneans. One of these statues cannot be repaired ; the other, which happened to be better preserved, is well repaired, and is set up under the piazza in the gate-way of the king's palace at Portici. This is a most beautiful statue, and is considered to be one of the best in the world. Not far from it, at the bottom of the palace stair-case, are fixed a beau-< tiful statue of the emperor Vitellius, very perfect and entire ; one of Nero, with a thunderbolt in his hand ; one of Vespasian ; one of Claudius ; one of Grermani- cus ; and 2 beautiful statues, sitting. There are many others, of marble, and of bronze, all larger than life ; and even some gigantic, or colossal ; many without heads, or arms, and others so destroyed as never to be repaired. Of busts, there are some very beautiful, as that of Jupiter Ammon, Neptune, Mercury, Juno, Ceres, Pallas, &c. In the apartments of the palace is a vast number of little statues, many of which are extremely beautiful : also a great number of little idols, tripods, lachrymatories, and many vases curiously wrought. Among these. 1 68 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. is a whole loaf of bread burnt to a coal ; which they will not suffer any one to touch. It is covered with a glass bell, through which are perceived letters on . the loaf, which possibly were the baker's mark. There are many other valuable curiosities locked up in the king's closet, and private apartments ; such as medals, intaglios, and cameos. Of the pictures, some were taken out of a temple near the theatre, others from the houses. They have all preserved their colours to admiration, which are very lively. They are painted in fresco, and were sawed out of the walls, with much trouble and care ; and are now fixed, with binding mortar, or cement, in shallow wooden cases, to prevent their breaking, and varnished over, to preserve their colours. You must think, that these pictures are not alike valuable, otherwise than from their antiquity ; some doubtless have been done by good hands, others by bad, as one sees by the works of those now-a-days. There are two as large as life. One of these pictures, they say, represents Theseus. The figure is naked, and holds a snnall club in his hand : between his legs lies a Mi- notaur, the posture of which produces a most admirable foreshortening. There stand about him also three little boys, one of which kisses his right hand, an- other embraces his left arm, and the third his left hand ; all extremely well ex- pressed. The other picture is of the same size as the former, and composed of many figures as large as life. A woman sitting with a wand in her hand, and crowned with flowers : on one side of her stands a basket of pomegranates, grapes, and other fruit : near her is a little satyr or fawn, playing on one of the ancient instruments, of 6 or 8 tubes, joined together in a row. There is a lusty naked man standing by her, with his face turned somewhat towards her, with a short black beard. He has a bow, a quiver of arrows, and a club. In the same piece is another woman, who appears talking to the first ; she is crowned with ears of com. There is also a hind giving suck to a boy, which they say represents the story of the discovery of Telephus. Another picture represents a winged Mer- cury, with a child sitting across his neck, near whom is a woman sitting, and taking Mercury by the hand. This, we were told, was supposed to be Bacchus carried to nurse. Another piece represented Jupiter embracing Ganymede. In another is a hunt of stags and swans. Three others, in each a Medusa's head. Another, representing two heads of imaginary animals. A beautiful one, re- presenting 1 of the muses, one playing on the lyre, the other with a mask on her head. Another, with a lion, a wood, and distant views. In another, various centaurs, buildings, &c. In another, a stag ; over which is a bird flying, and seeming to beak at him. Two other small pictures of a dolphin. Another with architecture, and distant views. One with a peacock. Another with a temple, adorned with various pillars. There have been also found two large cornucopias of bronze gilt, a large VOt. XLVII.] PHILOSOPHICAL TRANSACTIONS. 16Q round shield of metal, 2 metal dishes, several lachrymatories of glass, others of earth ; 4 large candlesticks of bronze, a large, metal vase with a handle ; many others of earth, curiously wrought ; the foot of a lion most curious, but in marble, and which supported a marble table ; a beautiful mascharron of metal, having the face of a cat, with a mouse in her mouth. There is also a very fine medallion, extremely well preserved, with a bas relief on both sides ; on one is a woman, near whom is a man naked killing a hog ; on the reverse is an old man, naked to his waist, sitting and playing on 2 pipes, which he holds in his hands. There is also another odd piece in bas relief, which represents a green parrot, drawn in a chariot, and driven by a green grasshopper, which sits on the box, as coachman. There are many baskets and cases full of diftbrent things, all jumbled together ; such as kitchen utensils, locks, bolts, rings, hinges, and all of brass. Things, that were of iron, were totally eaten up with rust. When the workmen came to any thing of that sort, it mouldered to dust as soon as they touched it ; occasioned doubtless by the dampness of the earth, and the many ages during which it lay buried. There were found many vases, and crystal bottles full of water ; but that might penetrate through the earth, and fall into them, if not close stopped : also a sort of standish, or inkhorn, in which were found many stylets or pens, with which they wrote in those days. When it was first taken out, they say the ink had not only its natural colour, but that it was yet capable of tinging : it is very dry now. There were eggs found quite whole, but empty ; also nuts and almonds ; grain of several sorts, beans and pease, burnt quite black. Many other sorts of fruit were found burnt quite to a coal, but whole and entire. - Mr. F. declares that he cannot be of the opinion of some, who assert that this city was suddenly swallowed up, which implies that the earth must have opened, and formed a pit to receive it. His opinion is, that it was overwhelmed with the boiling matter issuing from the mountain, at the time of the eruption ; because most things were found upright, chiefly the buildings. That it was not a sudden overwhelming, and that the inhabitants had time to escape with their lives, though not with their goods, is proved, by their not finding dead bodies, where they have hitherto dug. It is said that some human bones were found, though few. Very little money or plate has been found, or any other portable thing of great value ; which is another proof that the inhabitants were not destroyed. Doubtless before the violent eruption came on, the people for some days might perceive such tokens and signs, as could not but alarm them, and put them on their guard ; as at the eruption which happened in 1737, before it burst forth for some days, the inhabitants of Portici, and the adjacent villages, all retired ; being by some signs apprised of the event. The matter (called the lava) it seems is not of the same quality nor substance VOL. X. Zf "•'{ J«i*i-* i 170 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. all the \v:iy through the body of it; for in descending to the theatre, the sides of the passage at the entrance were a sort of mold, 8 or 10 feet thick; after which appeared stone of a blackish or dark grey colour, to the thickness of about 3 or 4 feet; then another layer of sandy earth, under which was a layer of the same sort of stone, and thus it continues stratum superstratum, to the bottom. The theatre and the houses seem all to have been filled with earth. In general, this stone is very hard and heavy, and the whole city of Naples is paved with it. Some of it will bear a fine polish, and of which they make snuff-boxes. XIX. Of the Hermaphrodite shown in London. By J. Parsons, M. D., F. R. S. p. 142. She was a French girl about 18 years old, and the true description of her pu- denda was as follows: What was mistaken for a penis, and had at first sight f;aused the deception, was the clitoris, grown to an inordinate size. The pre- puce of this was continued down on each side, to form the nymphae; under these the natural urethra was in its proper place, as in all females, and just under this was a natural vagina. This vagina was concealed by a skin growing up from the perinaeum, and continued to the labium of each side quite over it; which, if snipped with scissars, would lay the orifice of the vagina bare, and show the person a perfect female, having only this morbid size of the clitoris. This was really the fact, which any one might have been satisfied of, by passing a finger down under this skin to the perinaeum, when he would meet the orifice of the vagina, and find it as perfect as that of any other woman of the same age. The vagina being thus covered, and the clitoris thus large, it was no wonder, that she should at first sight be taken for a male by the vulgar; but it would seem a little too careless in any of the faculty to be so deceived. However if we consider the following observations, we shall find it no such strange affair, as it now seems to the world: nor is it new to find people imagine that, since this mistaken penis is imperforate, the urethra is preternatural ly directed to appear under it, without considering it to be a true female urethra, in its natural place. Dr. P. on the 30th of April, 1741, laid before the Society 7 or 8 female foetuses, fi-om about 6 to somewhat more than 7 months growth. Each of these had its clitoris larger in proportion than the present girl, or any other he had ever seen; which is the case with all female foetuses, during the greatest part of the time of gestation. And this is nature's common rule all over the world. Now it is impossible that so many hermaphrodites should be formed at once, since we have so few instances among the European nations of those so reputed; though they are common enough in Asia and Africa, in all those places especially that are nearest the equinoctial line, where the non-naturals themselves conduce much to the general relaxation of the solids in human bodies, and consequently to this unseemly accretion of that part. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 171 Now as the female foetus iiicreiises in the uterus in a natural way, the neigh- bouring parts of the pudenda grow more in proportion than the clitoris, drawing away the integuinents from it, whereby it becomes by degrees less conspicuous; and at length, as the child grows up, it is shrunk between the labia, and remains always covered, as it is now the common appearance in our women. But when it continues its growth, together with the neighbouring parts in the same pro- portion, which all female foetuses have it in, maintaining its first proportional size, the person, when grown up, is called by the vulgar a hermaphrodite; since the natural structure of this part is in a great measure like that of a penis virilis. Nor is its largeness in a foetus much to be wondered at, since there are other very similar cases in the same body, as the gland thymus and glandulae renales; both which, as the child grows larger, diminish in their proportion. These macroclitorideas are so numerous among many nations of Asia and Africa, that the ancients, Albucasis especially in his 71st chap, informs us of the necessary operation and method of cure, which he terms cura tentiginis, finding the part so called inconvenient from its largeness. Nor was this knowledge con- fined to men of science alone among the Egyptians and Ethiopians, and Angolans; for all parents know, when the child has these parts longer than ordinary, and they cut or burn them ofl^, while girls are very young, and at the same time never entertain the least notion of the existence of any other nature besides the true female, in those children who are thus deprived of that part. The learned De GraafF was well acquainted with this, and gives his approbation of the operation, as highly necessary, as well as decent: " estque hujus partis chirurgia orientalibus tam necessaria quam decora." It has been said too, that this girl in town had not the least appearance of breasts; but those who reported this, must surely have never seen the breasts of the women of any other nation but our own. On the contrary, she had as large breasts as any French girl of her age, and as good a nipple. Besides she was a thin girl, and small of her age ; and really among our own young women, when they are spare and small in stature, it will be hard to find any with breasts more conspicuous than hers, if so much. Dr. P. had considered this subject more at large in his Critical Inquiry into the Nature of Hermaphrodites, to which the reader is referred. XX. Of a very small Monkey.* Communicated by Jumen Parsons, M. D. F.R.S. p. 146. It is, from the tip of the nose to the root of the tail on the edge of the spine, * This aoimal is the timia iacchus of Linnxus. Striated monkey. Pennant. It is a native of South America. Z'2 172 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. only 7-^ inches; and the tail, from its root to the extremity, is Q inches; its face about an inch long; and hardly 4 of an inch broad at the eyes, where it is broadest. Its weight is about 44 oz. The face is naked, and of a flesh-colour; the eyes black, having no white part visible; the ears are thin, large in propor- tion, and of a dark colour ; and are surrounded each with a grove of very white hairs ; between which the hairs of the neck are blackish, and so are the 4 extre- mities; the rest of the body and tail is a mixture of dusky and yellow, so as to compose a dark olive; the hairs of the body are exceedingly soft, and each hair is parti-coloured, dusky at the root, then a little yellowish, then dark, and then yellowish again, somewhat like the soft feathers of partridges. The fingers are slender, each having 3 joints; they are 5 on each extremity, and are pointed by nails rather resembling the claws of birds, than those of human bodies; which is common to most other species of the cercopitheci. XXI. Abstract of a Letter from Naples, concerning Herculaneum, containing an Account and Description of the Place, and what has been found in it. p. 150. The entrance into Herculaneum is described to be down a narrow passage, cut with a gradual descent; and towards the bottom into steps, and the city is sup- posed to lie about 60 feet under the surface of the ground. Those who go down into it, carry each of them a wax taper, and are preceded by a guide. It is supposed that besides the earthquake, which swallowed up this town, it was also at the same time overwhelmed with the burning lava, which ran down from mount Vesuvius, during the eruption. And accordingly all the passages into it are cut through this lava; which is a very hard substance, like stone, of a slate colour, and said to be composed of various kinds of metals and glass ; which indeed is manifest in the appearance of it. The streets of Naples are paved with the same lava; but it seems to be of a much more soft and sandy substance in Herculaneum, than in the places where they dig it for use. The appearance of this city would greatly disappoint such, as should have raised their expectation to see in it spacious streets and fronts of houses ; for they would find nothing but long narrow passages, just high enough to walk upright in, with a basket on the head ; and wide enough for the workmen, who carry them, to pass each other, with the dirt they dig out. There is a vast number of these passages, cut one out of another; so that one might perhaps walk the space of 2 miles, by going up every turning. Their method of digging is this : whenever they find a wall, they clear a pas- sage along the side of it. When they come to an angle they turn with it; and when they come to a door or a window, they make their way into it. But when they have so done, they are far from finding themselves in a spacious room, or VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 178 open area; for all the rooms and places they have yet found, are so filled with lava, that it sticks on to the sides of the walls; and they can advance no farther than as they can make their way by digging ; which is such labour, that when they cease to find any thing worth their search, they fill up the place again, and begin to dig elsewhere. By which means no place is quite cleared. Conse- quently it does not appear how many stories high the houses may be ; nor is any thing to be seen over head but lava. In this are vast numbers of burnt beams, that seem to have been joists of floors ; though they are now little more than black dust; and where they are quite mouldered away, one may plainly see the grain of the wood imprinted on the lava, so close did it stick. A skeleton was found in a door-way, in a running attitude; with one arm ex- tended, which appeared to have had a bag of money in the hand of it, for the lava had taken so exact an impression of the man, that there was a hole under the hand of the extended arm ; which hole was apparently the impression of the bag, and several pieces of silver coin were found in it. This man therefore must have had notice enough of the danger, to endeavour to secure his treasure; though he must have been instantaneously encompassed with liquid fire, in at- tempting it. No manuscripts have yet been found; but they have met with some few inscriptions on marble, but none of any consequence, or which serve to give new light on any point of antiquity. The writer proceeds next to give some account of the paintings, and observes that, much the greatest part of them are little better than what you will see on an alehouse wall. They are all painted on plaster, which has been very carefully separated from the wall, in as large pieces as possible. These pieces are now framed, and there are above 1500 of them, but not above 20 that are tolerable. The best of them are 3 large pieces; one of which is a sort of history piece, containing 4 figures, with some expression in their faces; but even these best, if they were modern performances, would hardly be thought worthy of a place in a garret. There are about a dozen little pieces, of women dancing, centaurs, &c. the attitudes of which are very genteel, and the drawing pretty, but the shading is mere daubing. The colouring is allowed to be surprisingly fresh and well preserved, considering how long it has been done, but the painters seem to have been masters of only a few simple colours, and those not very good. The red is the brightest and best. The lava was found sticking to all the painting; which, some think, has helped to preserve it. The paint is liable to be rubbed off; to prevent which inconvenience, they have slightly varnished it. The designs of the greatest part of these paintings are so strange and uncouth, that it is almost impossible to guess what was aimed at. Much of it looks like such Chinese borders and ornaments as we see painted on skreens. There are 174 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. numbers of little figures dancing on ropes; a few small bad landscapes; and some very odd pieces, either emblematical, or perhaps only the painter's whim. Of which last the writer gives two specimens; one, of a grashopper driving a parrot, the other, of a vast great head, in the midst of what seems to have been intended for a green field encompassed with a hedge. The rest of this paper is only a repetition of that in art. 1 8 preceding, on the same subject. XXI I. An Occultation of the Planet Fisntis by the Moon in the Day time, ob- served at Mr. Short's, in Surrey street, London, April \6, 1751, O. S. By Dr. John Btvis. p. ISQ. The whole matter in this business was to direct a tube so, as to find out Venus a little before her ingress, and to manage the instrument so, as also to have sight of her at the instant of her egress. And knowing that Mr. Short is never un- provided with one or more instruments exceedingly well adapted to this and other purposes, the same that he has described in Phil. Trans. N° 493 ; which, for its easy removal from place to place, may be considered as a sort of portable obser- vatory. Dr. B. intimated his intention to him the evening before; who was so kind as to set up two of the said instruments, which he found rectified, and ready for observation, when he visited him the. next morning. One of these, placed near his clock, he intended for his own use, and the other was for the Doctor. The air was of itself clear; but the wind, being in the north-east quarter, brought such drifts of smoke, as much impaired the distinctness of Venus, which however looked round. Several minutes before Dr. B. expected it, the figure of the planet was manifestly altered; on which he called out to Mr. Short to hasten to his instrument, which he did, though too late. The total ingress was at 10*' 39"" 30* by the watch. From his first perceiving the change of the figure, to the entire ingress, could not be a full minute. He observes, that not a glimpse of the moon, then not 1 days old, could be discerned; so that the business of securing Venus, at the instant of her emer- sion within the field of the telescope, over which she passed in about 2™ 10*, depended entirely on a due management of the screw, which gave motion both to the equatorial or horary plate, and to the telescope. A little after 1 1 he brought the point of the hour circle, answering to Venus, to the index, and might then have seen her near the middle of the field, had she already emerged. Every 1 minutes after he was careful to turn the screw so much, as to be sure of keeping her within the field. At length setting his eye to the instrument imme- diately after one of these operations, he perceived her quite emerged and round: VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. \f;S this was at 1 1** 13"' 15^ by the watch, which still kept exact pace with the clock; and his eye had not been removed more than a minute. Venus passed the meridian in the transitory at l*" 37"" 55' afternoon by the clock: the sun passed this day at ll'^ 57'" 27% and yesterday, the 15th, at ll'' 57"" 28^; whence it is easy to reduce all to apparent time, as follows: Total ingress of Venus 1751, April 15'^ '22^ 42'" 2' Her total emersion 15 23 15 47 Her meridian transit l6 1 40 29 Now, supposing the whole disk to have taken up one minute, as it seemed thereabout, both in the ingress and egress, the middle of the occultation must have been 15 22 58 24-1- And the duration, with respect to the centre of Venus .... 33 45 P. S. Mr. John Canton sent notice that he observed the occultation of Venus by the moon last Tuesday, at his house in Spital-square, and found the immer- sion at 10'' 42*" 20" a. m. emersion at ll'' 15"" 40*. XXIII. Of a remarkable ^"fppearance in the Moon, Jjjril 22, 1751. By James Short, F.R.S. p. 164. In N° 396 of the Phil. Trans, there is an account of an observation made on an uncommon appearance of the lunar spot called Plato in the nomenclature of Riccioli's and Grimaldi's "Selenography, and Lacus niger major in that of Heve- lius. Signor Bianchini, to whom we owe this communication, says, that it was the 16th of August, 1725, N. s. about an hour after sun-set, when he took his observation with a dioptric telescope, of 1 10 feet, made by the famous Campani, the air being very serene, and the moon, as he says, speaking of the same phe- nomenon in his book of Venus, a day past the first quarter: so that the said spot then lay in the common section of light and darkness. The mountainous oval margin, with which it is surrounded, was brightly illumined with the sun's rays; but the plain bottom looked darkish, as having not yet received his light. There was however extended along its area, from end to end, a track of reddish light, as if a beam had been admitted through some perforation in that side of the margin, which was then exposed to the sun. M. Bianchini proposes the so- lution of this matter in two different ways: first, by supposing an aperture in the margin, as just now mentioned: or secondly, by conceiving the moon to have an atmosphere, and that thereby the rays passing near the summit of the margin might be so refracted as to be thrown on the plain area or bottom. Mr. S. having lately had an opportunity of observing something of the same nature himself, he here lays it before the Society, with a conjecture concerning its cause. Monday, April 22, 1751, o. s. being at Marlborough house, and having directed the great reflector to the moon, he perceived a single streak of 176 PHILOSOPHICAL TRANSACTIONS. [anNO 1751. light projected along the flat bottom of the spot Plato; and from what he was then able to recollect of Bianchini's narrative, he doubted not but that it was of the same kind with that he saw, and which he had so often looked for in vain. By the position of the spot on the disk, and the shadow of the mountains on the west side of it, we should not have expected to have seen any light on the bottom. Soon after he discerned another streak of light extended along the bottom, parallel to the first, but somewhat lower, which in a very short time was evidently divided into two. He sought in vain for such a perforation, as that hinted at in the other account; but through the great magnifying power of this instrument, he was able to discover a gap or notch in the mountains to the westward, which abutted against the first streak or stream, and pursuing the object with great attention, he also perceived a similar gap in the direction of the lower streak; but though this streak was divided into two, he was not able at any rate to find out another notch, by which to account satisfactorily for the whole appearance; which he would have considered as solved, could such a one have been discerned in a right situation. XXIV. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the Royal Society by the Company of Apothecaries for the Year 1750, pur- - suant to the Direction of Sir Hans Shane, Bart. p. ^66. [This is the 29th presentation of this kind, completing the number of 1450 different plants.] XXV. Observations on the Sex of Flowers. By W. ffatson, F. R. S. occasioned by a Letter on the same Subject, by Mr. My litis of Berlin, p. 169. i Extract of Mr. Mylius's Letter to Mr. Watson, dated at Berlin, Feb. 20, 1750-51. — " The sex of plants is very well confirmed by an experiment which has been made on the palma major foliis flabelliformibus. There is a great tree of this kind in the garden of the royal academy. It has flowered and born fruit these 30 years; but the fruit never ripened, and when planted, it did not vege- tate. The palm-tree, as you know, is a planta dioecia; that is, one of those in which the male and female parts of generation are on different plants. We having therefore no male plant, the flowers of our female were never impregnated by the farina of the male. There is a male plant of this kind in a garden at Leipsic, 20 German miles from Berlin. We procured from thence in April 1749 a branch of male flowers, and suspended it over our female ones, and our experiment succeeded so well, that our palm tree produced more than 100 per- fectly ripe fruit; from which we have already 11 young palm trees. This expe- riment was repeated last year, and our palm tree bore above 2000 ripe fruit. As I do not remember a like experiment, I thought convenient to mention it to VOL XLVII.] PHILOSOPHICAL TRANSACTIONS. 177 you; and, if you think, proper, be pleased to communicate it to the Royal Society." In pursuance of his correspondent's desire, Mr. Watson lays this account be- fore the Royal Society, which he thinks very curious ; not on account of its no- velty, or of its confirming the sex of plants, which is now sufficiently esta- blished; but on account of the male and female palm-tree's flourishing so com- pletely in such high latitudes as those of Leipsic and Berlin. The impregnation of the female palm tree by the male has been known in the most ancient times. Herodotus, when speaking of the palm tree, says, " that the Greeks call some of these trees male, the fruit of which they bind to the other kind, which bears dates: that the small flies, with which the male abounds, may assist in ripening the fruit; for, says this author, the male palm tree pro- duces in its fruit small flies, just as the fig tree does." The very remote age, in which Herodotus wrote, sufficiently apologizes for his believing, that what was really brought about by the farina foecundans of the male flower, was to be attri- buted to the insects frequently found in it, and which perhaps very often do carry this farina from the male to the female. They had seen the effects of caprifica- tion in fig trees by these insects, and were misled by the analogy. They are here translated small flies ; but they had a particular appellation given them by Hero- dotus, Aristotle, and Theophrastus, who call them 4"ii'- Pliny, in his history, when treating of caprification, which is almost a translation from Theophrastus, calls them culices, Linneus ichneumones, and Tournefort moucherons. Theo- phrastus, in his account of the palm tree, gives the very process mentioned by our correspondent. " They bring together, says he, the males and the females, which causes the fruit to continue and ripen on the trees. Some, from the simi- litude of this to what happens in fig trees, call it caprification; and it is per- formed in the following manner: while the male plant is in flower, they cut off a branch of these flowers, and scatter the dust and down in it on the flowers of the female plant. By these means the female does not cast her fruit, but pre- serves them to maturity." Pliny also mentions the like process. Among more modern authors, Prosper Alpinus, gives at large the manner of the impregnation of the female palm tree by the male, for the purposes before-mentioned. We have also copious accounts of the same process by Tournefort, Kaempfer, and Ludwig. As Kaempfer was an eye-witness, his account of this matter is most to be depended on. Mr. W. observes, that though the ancients distinguished rightly, in deter- mining the true sexes of the palm tree, it is the only plant in which they have not erred. Though they called plants of the same genus, or of others very nearly related to it, male and female, it was on an imaginary, a false principle: and that usually taken from their size, the difference of their leaves, or the figure of VOL. X. . A A 178 PHILOSOPHICAL TRANSACTIONS, [aNNO J751. tlieir fruit; and what therefore they have denominated male and female, must not with the modern exactness be rigorously considered as such. Thus Aristotle, after having taken notice that there was the distinction of male and female ob- servable in plants, says, " that the male plant is more rough and strong, the fe- male more weak and fruitful." And Theophrastus, when speaking of the male and female pine tree, says, " that the Macedonians have trees nearly related to pines, of which the male is of shorter growth, and has harder leaves; that the female is taller, and has its leaves softer and more fleshy." He says, on his own authority, " that the wood of the male pine is hard, that of the female more soft." Pliny also in his history gives a like reason for his distinguishing the sex of the pine: he says further, in another part of the valuable monument he has left us, " that the most expert naturalists assert, that every tree, and every herb, which the earth produces, has both sexes;" but this is to be understood in the manner just mentioned; and so likewise is the distinction among the more mo- dern botanists in their denominations of several plants, such as veronica, eupa- torium, anagallis, tilia, paeonia, balsamita, filix, quercus, orchis, laureola, abro- tanum, com us, polygonum, equisetum, mandragora, and others, which are termed imaginarily male and female; as the discovery of the real sex of plants was reserved for the accuracy of the present age. Besides the before-mentioned erroneous principle, from which the ancients, as well as some more modeiTi authors, determined the sex of plants, there is yet another, and that is, a deno- mination of plants from their sex, which is absolutely false; and in order to elu- cidate this position, and to show at the same time in what the sex of plants really consists. Mr. W. premises, that it is in the flowers of vegetables only that the parts subservient to generation are produced. Simple flowers, to use this term in opposition to the compound flowers of the botanists, are either male, female, or hermaphrodite. By male flowers, he means those which are possessed only of those organs of generation analogous to the male parts of animals; and these are what former botanists have denominated stamina and apices, but are since named more properly by Linneus, filamentum and anthera. The female flower is only endowed with parts like those which perform the office of generation in females; and these are the pistillum and its appurtenances, which, by Linneus, with his accustomed accuracy, are divided into three parts, viz. the germen, stylus, and stigma. The hermaphrodite flower, which constitutes the great bulk of the vegetable creation, is possessed of all these parts in itself, and is itself thus capable of propagating its species without any foreign assistance; which, by many incontestible experiments, it has been found neither the male nor female flower simply is able to do. Much the greater number of plants, as just hinted, have hermaphrodite flowers; but there are some which have both the male and female flowers growing from the same root. Such are mayz, or Indian corn, VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 179 nettles, box, elm, birch, oak, walnut, beech, hazel, hornbeam, the plane tree, pine, fir, cypress, cedar, the larch tree, melons, cucumbers, gourds, and several others. In many of these, though the male and female flowers are at consider- able distances, the farina foecundans, which Providence, on account of its being liable to be spoiled by rain, or dissipated by winds, has provided in great abun- dance, is conveyed to the female by means of the atmosphere. It is this class of vegetables, and the following, the quantity of the produce of which is much more precarious than those plants which have hermaphrodite flowers ; as the im- pregnation of these last may be performed within their own calyx; whereas the fonner must necessarily commit their farina to the circumambient air. It is for this reason that if, during the time of the flowering of these plants, the weather is either very wet or stormy, their produce of fruit is very inconsiderable, from the spoiling or hasty dissipation of the male farina. Thus, independent of frosts, the fniit of the nut and filberd tree is most numerous in those years, in which the months of January and February are the least stormy and wet, as at that time their flowers are produced. For the same reasons, a stormy or wet May destroys the chesnuts; and the same weather in July prodigiously lessens the crop of mayz or Indian corn, as its spikes of male flowers stand lofty, and at a considerable distance from the female. In like manner a judgment may be formed of the rest of these. Some of the more skilful modern gardeners put in practice, with regard to melons and cucumbers, the very method mentioned by Theophrastus 200O years ago, in regard to the palm tree. As these plants, early in the sea- son, are in this climate confined to frames and glasses, the air, in which they grow, is more stagnant than the open air, by which the distribution of the farina foecundans, so necessary towards the production of the fruit for the propagation of the species, is much hindered ; to obviate which, they collect the male flowers when fully blown, and presenting them to the female ones, by a stroke of the finger they scatter the farina foecundans in them, which prevents the falling of the fruit immaturely. Besides the vegetables before-mentioned, which bear male and female flowers on the same root, there are others, which produce these oigans on different roots: in the number of these are the palm-tree, (the more particular subject of this paper,) hops, the willow-tree, misletoe, spinach, hemp, poplar, French and dog's mercury, the yew-tree, juniper, and several others. Among these, the valisneria of Linneus, as to the manner in which its male flower impregnates the female, is one of the most singular prodigies in nature. The manner of this operation is figured by Micheli, in his Nova Plantarum Genera, and described by Linneus, in the Hortus Clifibrtianus. As that elaborate and expensive work is in very few hands, Mr. W. here gives a short account of it. The valisneria grows in rivulets, ditches, and ponds, in many parts of Europe. A A 2 180 VHILOSOPHICAL TRANSACTIONS. | ANNO 1751. The male plant, which is continually covered with water, has a short stalk, on the top of which its flowers are produced. As this top never reaches the sur- face of the water, the flowers are thrown off" from it, and come unopened to the surface of the water ; where, as soon as they arrive, by the action of the air, they expand themselves, and swim round the female flowers, which are blown at the same time. These last have a long spiral foot-stalk, by which they attain the surface of the water, and remaining there in flower a few days, are impreg- nated by the male flowers detached from the stalk at the bottom. This opera- tion seems to be thus directed, as the farina foecundans could not exert its effects in so dense a medium as water; and we find that even the hermaphrodite flowers of water-plants, such as those of potamogiton, renunculus aquaticus, hottonia, and nymphasa, never expand themselves till they reach the surface of the water. But to return : it was not possible for Mr. W. without premising these things, to make evident what he just now mentioned, in regard to the falsely denomi- nating the sexes of plants ; as it is to this last class that the wrong application has been made by botanical writers. This error seems to have been first in- troduced as early as Dioscorides, and has been continued through a great va- riety of writers, even to our own time. It is most certain, that those plants, which produce the seed, ought to be considered as females ; but it happens that in the French and dog's mercury, the seeds are produced in the female plants by pairs ; and these are contained in a capsule, which was thought to resemble the scrotum of animals; and from this testiculated appearance they called these plants males, and the others females. Thus, for example, Dioscorides, when treating of mercurialis, or what we here call French mercury, says, " the seed of the female is produced in bunches, and is copious ; that of the male grows near the leaves ; it is small and round, and disposed in pairs like testicles." Do donaeus, Lobel, Delechamp, John and Caspar Bauhin, Morrison, Tournefort, and Boerhaave, in their several works, have followed Dioscorides, and have de- nominated the seed-bearing plant of this kind, the male ; and the other, the fe- male. Fuchsius and John Bauhin likewise call the cynocrambe or dog's mer cury, which bears fruit, the male ; and the spiked one with male flowers only, the female. This mistake is observable in hemp, hops, and spinach. We observe that the operations of nature are carried on most usually by cer- tain general laws, from which however she sometimes deviates. Thus almost all plants have either hermaphrodite flowers, or male and female flowers, grow- ing from the same root, or male and female flowers from different roots : but there are a few of another class, which fi-om the same root furnish either male and hermaphrodite flowers, or female and hermaphrodite flowers. Of this kind are the mulberry-tree, the musa or plantain-tree, white hellebore, pellitory, ar- rachj the ash-tree, and a few others. But of this class the empetrum or berry- VOL. XLVII.^ PHILOSOPHICAL TRANSACTIONS. 181 bearing heath is the most extraordinary ; as of this are found some plants with male flowers only, others with both male and female flowers separately, and still others with hermaphrodite flowers. What Pere Labat mentions in his Voyage a r Afrique Occidentale should likewise be taken notice of here. This author, after having laid down the difierent methods of impregnating the female palm- tree by the male, says, that this process is not absolutely necessary for the pro- duction of dates ; for being at Martinico, he there saw growing by an old con- vent near the place, where they anchored, a palm-tree bearing dates, though the only one of its kind which was thereabouts. Whether it was male or fe- male, he did not pretend to determine, but was certain, that there then was none, nor had been any, within 2 leagues of the place where it grew. He doubts indeed whether this tree bearing fruit did not proceed from the farina foecundans of the male cocoa tree, which is a species of palm, and which grew in abundance near the tree that bore dates : but he observes, that the stones of these dates did not vegetate, and that those who were desirous of propagating date-trees, were obliged to plant the Barbary dates ; as he believed the others had not the germ proper to produce the tree. From this account it is very ob- vious, that the palm-tree here mentioned, was a female, in which though the fruit ripened, it was in such a state of imperfection, as not to be able to propa- gate its species. In this manner we have eggs furnished by hens without a cock ; but these eggs produce no chickens. What this father says of the female palm- tree's bearing fruit without the assistance of the male, Mr. Miller says, has been fully confirmed to him by several persons : and John Bauhin, an author of great credit, describes and figures the whole fructification of a palm-tree, which he saw growing at Montpelier, and which not only produced branches of male flowers, but also female ones bearing dates. Mr. Ray many years after tells us in his history of plants, that at Montpelier he saw this very remarkable tree men- tioned by John Bauhin. This variety in the fructification of the palm-tree, sin- gular as it may seem, has been likewise observed in some few others. The learned Jungius, in his Doxoscopia, mentioning that class of trees which are male and female in different parts of the same tree, says, " that trees of this kind, when they have for many years, produced flowers without fruit, afterwards pro- duce fruit without flowers. This, he thinks, should be further inquired into." This, since Jungius's time, has been done, and it has been found, that some- times some of the trees of this class are wholly male, while young ; but as they advance in age, they have flowers of both sexes, and afterwards become entirely female. This fact Mr. Miller has frequently himself observed in the mulberry- tree ; and the Chevalier Rathgeb, a gentleman excellently well versetl in what- ever relates to vegetation, has observed, that a large lentiscus, or mastich-tree 182 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. near his garden, had for 30 years produced only male flowers, but that for 3 years past it had produced plenty of fruit. The foundation of the discovery of the real sex of plants, which is of no less importance in natural history, than that of the circulation of the blood in the animal economy, was laid by the members of this learned Society ; though much of the honour due to them is attributed by foreigners to the late ingenious Mons. Vaillant of Paris : and this may have arisen from our language not being gene- rally understood on the rx)ntinent. Sir Thomas Millington, sometime Sedleian lecturer of natural philosophy at Oxford, as we see by our worthy member Dr. Grew's anatomy of plants, seems first to have assigned a more noble purpose to the stamina and apices of flowers, than that which had been attributed by pre- ceding writers, and by Mons. Tournefort afterwards; viz. that of secreting some excrementitious juices, which were supposed hurtful to the embryos of the fruit. Sir Thomas conjectured, and rightly, " that the stamina and apices served as the male for the generation of seed." This hint, which was afterwards adopted by Mr. Ray, in the preface to his Sylloge Stirpium Exterarum, Dr. Grew carried farther, as we find by his works ; and it was followed by Camerarius, professor at Tubingen: but our member Mr. Morland, afterwards pursued this inquiry much higher, as we see by his memoir published in the Phil. Trans. N° 287. After these, Messrs. Vaillant and Geofiroy illustrated and strengthened these discoveries by very curious experiments; so that now nothing seems wanting for the confirmation of the truth of this doctrine. So much for the discovery of the sex of plants in general, on which Linneus has founded his system of botany, at present so much and so well received. Whoever therefore would consider minutely the structure of flowers, and the al- most infinite variety of the number and disposition of their parts, may consult Linneus's Philosophia Botanica lately published, where this subject is treated in a very copious and instructive manner, XXPI. On a small Species of fVasps.* By Mr. John Harrison of Cambridge, in New England, p. 184. About the 28th of May, Mr. H. discovered hanging to the roof on the inside of a green-house (which was of wood) something about the size of a child's farthing ball, in shape like a Provence rose full grown, before it opens, that is, a round bottom, ending in a blunt point , at which point was a round hole, large enough for insects (something less than a wasp) to go in and out at. He soon perceived that it was the work of insects, a small species of wasps. They have 6 legs, * See a pretty good representation of nests of this kind in the 6th vol. of Reaumur's Hist, of Insects, pi. 19. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 183 black near tlie body, then yellow, ending in cinnamon colour. Some have 6 or 7 rings, of a bright yellow colour round the tail part, with small hollows or in- dents on the upper parts. The divisions between the rings are of" a bright jet colour ; the face is yellow ; on the head are 2 horns. These insects are very in- dustrious in making their nest. The top is fastened to the ceiling, and formed of many round coverings, one within another, yet not touching each other, by the 8th of an inch. Probably this space is left to make the cells, in which they lay their eggs. Their manner of working is curious, and as it is principally perfomied exter- nally there is an opportunity of seeing every circumstance of the operation, which is carried on with as much application, and perhaps more skill and contrivance than the honey-bees, who are beholden to a hive or hollow tree, &c. to fabricate their combs in ; whereas these little animals are the sole builders of the outer walls, as well as the interior parts of their dwellings. They range about for the materials, but with all his endeavours Mr. H. could never observe from whence they were collected ; only that they bring a little lump of dark-coloured paste between their fore legs, about the size of a radish seed. This they carry first to the inside of the covering, which they are about to finish, and stay near half a minute, probably to work some of it on that side ; then they return with the greatest part, to enlarge it on the outside, which they execute in a most dextrous manner, by taking the paste from between their legs with their mouths, (which open cross ways to their body) and fixing it on the edge of the covering, working backwards, for about an inch at a time in length, and then spread and smooth it with their horns. This is all performed in about 2 minutes, and they are seldom more than 5 days in finishing a whole cover. Their number is only between 20 and 30. They seem not at all hurtful ; and are so intent on their business, that if 3 or 4 people at a time are looking within so many inches of their nest, they neither attack them, nor forbear to carry on the public work, which comes to be about 5 inches diameter, and about 4 deep. They continued their work till they had finished J 5 coverings one over another, and began 3 more, which they never completed. About the l6th of August there was a cessation of their usual industry. There was only one or two in a day at work, which continual to the 26th, when they quite gave over adding any more to their nest. Since that, he could only see one or two going in and out once or twice a day, for about a fortnight after. In that time he observed 2 of these insects come out of their nest, of an extraordinary size, at least one-third larger than those that built the nest. These seem, and doubtless are, the parents or queens appointed by the all-wise Creator for continuing their species, as their sluggishness has a near analogy to the queen-bees, that are sometimes seen to 184 PHILOSOPHICAL TRANSACTIONS. [anNO 1751. come to the mouth of the hive, without any other seeming business than to take the air, and show themselves, and then return into the hive again. About the 6th or 7th of September, he saw the last ; none were afterwards seen (Dec. 22). If these insects may be compared to hornets, which they most resemble, in their making and hanging up of their nest, the queens will only survive, and each in the next spring be the founder of a new colony. The common wasps are under the same regulation. The males die at the approach of winter, and leave but few females to survive them. This is wonderfully contrived to prevent the in- crease of such noxious animals ; whereas the bees, so beneficial to mankind, survive the winter, unless robbed of their honey, which is their support during that season. In the spring, finding none of the insects appeared, Mr. H. took down the nest, which he found had been quite deserted. XXFIl. Concerning Mr. Bright, the Fat Man at Maiden in Essex. By T. Cole, M.D. Dated Chelmsford, Jprd \Q, 1751, p. 188. Mr. Edward Bright, grocer, of Maiden in Essex, died there the 10th of November 1750, in the 30th year of his age. He was a man so extremely fat, and of such an uncommon bulk and weight, that there are very few, if any, such instances to be found in any country, or on record in any books. He was descended from families greatly inclined to corpulency, both on his father's and his mother's side. He was always fat from a child, yet strong and active, and used much exercise, not only when a boy, but till within the last 2 or 3 years of his life, when he became too unwieldy. He could walk nimbly, having great strength of muscles, and could not only ride on horseback, but would some- times gallop after he became between 30 and 40 stone weight. He used to go to London about his business, till the journey (40 miles) became too great a fatigue to him ; so that he left it off some years before he died. In the last year or two he could walk but a little way, being soon tired, and out of breath. At 124- years old he weighed 144 pounds ; and before he was 20 he weighed 24 stone or 336 pounds. The last time he was weighed, about 13 months before he died, his weight, exclusive of his clothes, was 41 stones and 10 pounds, or 584 pounds. What it exactly was at the time of his death, cannot be told; but as it was manifestly increased smce the last weighing, if we take the same propor- tion by which it had increased for many years on an average ; viz. about 2 stone a year, and only allow 4 pounds addition for the last year, on account of his moving about but little, while he continued to eat and drink as before, this will bring him to 44 stone or 6l6 pounds neat weight. As to his measure, he was 5 feet 94- inches high. His body round the chest just under the arms measured 5 feet 6 inches, and round the belly 6 feet 1 1 VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 185 inches. His arm in the middle of it was 2 feet 2 inches about, and his leg 2 feet 8 inches. He had always a good appetite, and when a youth used to eat somewhat re- markably ; but toward the end of his life, though he continued to eat heartily, and with a good relish, yet he did not eat more in quantity than many other men of good appetite. Though he did not take any liquor to an intoxicating degree, yet perhaps on the whole he drank more than might have been advisable to a man of his very corpulent disposition. When he was a very young man, he was fond of ale and old strong beer ; but afterwards his chief liquor was small beer, of which he commonly drank about a gallon in a day. In other liquors he was extremely moderate, when by himself, sometimes drinking half a pint of wine after dinner, or a little punch, and seldom exceeding his quantity; but when he was in company, he did not confine himself to so small an allowance. He enjoyed for the most part as good health as any man, except that in the last 3 years, he was 2 or 3 times seized with an inflammation in his leg, attended with a little fever ; and every time, with such a tendency to mortification, as to make it necessary to scarify the part. But by the help of scarifications and fo- mentations, bleeding largely once or twice in the arm, and purging, he was always soon relieved. He married when 22 or 23 years old, and lived a little more than 7 years in that state ; in which time he had 5 children born, and left his wife with child of the 6th, near her time. His last illness, which continued about 14 days, was a miliary fever. It began with pretty strong inflammatory symptoms, a very troublesome cough, great difficulty of breathing, &c. and the eruption was extremely violent. His body began to putrify very soon after he was dead ; so that notwithstanding the wea- ther was cool, it became very offensive the next day before a coffin could be made. The coffin was 3 feet 6 inches broad at the shoulders, 2 feet 3^ inches at the head, 22 inches at the feet, and 3 feet I4 inch deep. '' XXFIII. The Effects of the Hyoscyamus Albus* or White Henbane. By Dr. J. Stedman, late Surgeon Major to the Regiment of the Royal Grey Dragoons. p. 194. In the month of August 1748, while the Greys were cantoned in the village of Vucht near Boisleduc in Dutch Brabant, 5 men and 2 women of that regiment having eaten of the leaves of the hyoscyamus albus, shred and boiled in broth, were soon after seized with a giddiness and stupor, as if drunk. Dr. S. saw them • The plant here mentioned was, as Mr. Watson afterwards remarks, the hyoscyamus iiiger, Linn, or common henbane ' VOL. X. Bb • J86 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. about 3 honrs after eating of it ; and then 3 of the men were become quite in- sensible, did not know their comrades, talked incoherently, and were in as high a delirium as people in the rage of a fever. They all had low irregular pulses, slavered, and frequently changed colour: their eyes looked fiery, and they catched at whatever lay next them, calling out that it was going to fall. They complained of their legs being powerless. He mixed what ipecacuanha he had with him in warm water, and made them drink it ; and afterwards threw in as much warm water and oil, as he could prevail with them to swallow. Those who were not insensible vomited freely, and were relieved by it. Two of the 3 affected with delirium, though they drank great quantities, did not vomit, but had profuse sweats, and passed plenty of urine, by which they were likewise somewhat relieved. The 3d of these was obstinate, and could not be prevailed on to do any thing. The symptoms with him continued longer, and were more violent. He was so restless, that though he could not walk, 2 of his comrades were not able to keep him in a chair. Next morning they had no other com- plaint than people commonly have after great drinking ; but afterwards (though the danger seemed over) some of them complained of feebleness and a weight at their stomachs ; others, of gripes, stitches, headach ; and all of them were ver- tiginous at times. These complaints continued above a month after the accident. One of the women had her hands stiff and swelled; whether from the action of the vomit, or the force of the poison, he knew not. The man who gathered these leaves in mistake for another plant, said, that from the nearest conjecture he could make, there might be from 15 to 20 leaves, boiled in about 10 quarts of water. They did not eat half of that quantity, and the poison began to dis- cover itself with some of them in half an hour. This seemed to be the hyoscy- ainus major albus of Caspar Bauhin. It is easily known by its large duskish bell-fiower ; but if not in the flower, the remarkably noisome smell of the leaf, somewhat narcotic, if once known, will ever after discover it. Some time before this accident, some of the horses had been put into an orchard, where they cropped the branches of these trees, and in about 4 hours, without any previous symptom of disorder, dropped down, and after a struggle of a minute or two died. This was probably about the time that the juice entered the blood. Remarks by Mr. Wm. IVatson, F.R.S. — On reading the above paper, Mr. Watson observed, that the effects could not arise from the hyoscyamus albus, or white henbane, as Dr. Stedman imagines ; that plant, from the concurrent tes- timony of the best botanical writers, not being found so far north as Brabant : but the mischief was done by the hyoscyamus niger, or black henbane, which grows plentifully there, as well as almost all over Europe in uncultivated places, and by the sides of roads. The white on the contrary is sown in gardens, and VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 18? not found spontaneous in higher latitudes than the southern parts of France. Dr. Stednian's description demonstrates likewise that the above plant was the hyoscyamus nigcr, as he says, that ' it is known by its duskish bell-flower.' The flower of black henbane is of that hue, being of a yellow colour interspersed with veins of purple ; whereas the flower of the white henbane is of a pale yellow colour. This error arises from the improper denomination imposed on many plants by the ancients, and which has been preserved even since the revival of letters ; which, to one not very well acquainted with botany, is liable to mislead. Thus, in the case before us, the leaves of the black henbane are very little less white than those of the white ; but this denomination took its rise from the difr ferent colour of their seeds. In such cases therefore, without being well ac- quainted with the specific difference of each plant, before it ripens its seed, it is not a little difficult to distinguish them one from the other. This specific dif- ference will be best furnished by the leaves. Thus in the henbane, the leaves of the white are placed on long footstalks ; those of the black have none, but the lower extremity of the leaf surrounds the stalk. XXIX. The best Proportions for Steam-engine Cylinders, of a Given Content, considered. By Francis Blake * Esq. F.R.S. p. 197. The steam-engine, for draining of mines, is a master-piece of machinery, a very capital contrivance in the works of art, and meriting our attention for fur- ther improvements. The prodigious vessel of water to be kept always boiling, when only an inconsiderable part of it is employed in the work, savours too little of the frugality of nature, which we ought ever to imitate. But waving that now, what Mr. B. inquires into here, and endeavours to regulate, is the propor- tion of the cylinder's altitude and base ; which has not been hitherto noticed. It is evident, in the first place, from a general law of mechanics, that the content of the cylinder remaining the same, the quantity of water discharged at each lift will in all cases be equal, by only changing the distance of the centre of the piston from the fulcrum of the balance. It will be granted also that the excess of the column of atmosphere, above that of the water, is a weight on the piston, driving it to a depth of about 5 feet, by the present construction, within the cylinder ; acceleratedly till friction and an impediment from the steam, which remains in the cylinder even after the jet d'eau, and is increased in elasticity while its bounds are diminished, shall equal the accelerative force ; and that then again the piston is retarded the rest of the way. It may be convenient to re- * Francis Blake, Esq. a gentleman of great fortune, and a very learned map, was the father of tl|e present Sir Francis Blake, Bart, of Twizel Castle in the county of Northunjberland, also a learned and very respectable characier. . , ,5^"" 4 B B 2 188 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. mark too, that if the rarefaction be so complete, that the descent would be greater than the construction admits of, the retardation is augmented by a brachium of the balance pressing on springs. But to say nothing of friction here, we can, notwithstanding this diminution of force by the remainder of steam within the cavity of the cylinder, demonstrate the ratio of the velocities, and the times of descent of the pistons, in cylinders of unequal altitudes, to be exactly the same as if the resistance was nothing ; whence we shall without difficulty arrive at some conclusion in this matter. MN is the working part of a steam engine cylinder, of the usual height, equal in diameter to a shorter one m n, fig. 1, pi. 6; and the rarefaction in both of them being supposed the same, AG=aq, RQ=rq, and AR=ar, may represent the ex- cess of the atmosphere's weight above the column of water, the resistance to the pistons from the remainder of steam, and the effective force, respectively, e. g. at the beginning of the descent. Take then every where ak: ak:: an: an, and at all similar positions the resistance b c of m n and force k c on its piston, will be equal to the resistance b c of m n and force k c on its piston ; and by what Sir Isaac Newton has demonstrated (Book 1, Prop. 39,) of the descent of bodies, we have y^akcr: ^akcr:: celerity in k: celerity in k. But these areas being evidently as the corresponding parallelograms kq and kq, and these again as their heights, the celerities generated are in the subduplicate ratio of ak: ak, as if the resistance had been nothing ; and by an obvious enough reasoning from the said proposition, the times also appear to be in the above-mentioned ratio ; which ratio is not any way varied, though the resistance prevails from the inter- secting points o. Now, to apply what has been said to the business in hand ; if t w be a cylinder of equal content with the cylinder mn, the quantity of water delivered by both will, as a consequence of the fundamental law of mechanics observed above, be the same at each lift : but the cylinder t w is no higher than n m, and ex hypoth. their rarefactions are equal ; therefore by what has been proved with regard to the times, the time of the piston's descent in t w, will be to that of the piston's descent in mn:: y^Ew: \/an; whence in any given time the broad cylinder t w will perform more than the longer one m n of equal content, and that in the ratio of their diameters; for fe^ X ew = ma^ X an ex hypoth. andEw: an:: ma'^: et% consequently v'ew: v'an:: ma: te. The friction too is diminished with the slowness of the motion, and because the periphery in- creases in a less ratio than does the area of a circle. The result of the whole then is in favour of the broad cylinder ; and still the broader the better ; for unless some mechanical considerations should limit the problem, it is evident in a geometrical sense, that there is no limitation. A disadvantage might arise perhaps to the effect of the jet d'eau from thus increas- VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 189 ing the breadth ; which howevec would probably be remedied by a number of these jets : but be that as it may, it is certain, that to augment the diameters, and diminish the lengths of the smaller kind of cylinders, now used, could have no such inconvenience, nor fail of being attended with an augmentation of force. XXX. Mr. John Bradley s Observation of the Occultation of Fenus by the Moon. Communicated by Mr. James Short, F.R.S. p. 201. Mr. Gael Morris having favoured Mr. Short with the observation of the late occultation of Venus by the moon, taken at Greenwich with great exactness by Mr. John Bradley, he laid the same before the Royal Society, in order to show its very near agreement with those phases, which Dr. Bevis observed at his house in Surry-street, allowing for the difference of meridians. Apparent time. 1751 April 15, 22*' 41"" 45' The first contact; doubtful to 1 second. 42 18 Quite immerged. 23 15 3 6-1- Began to emerge. 16 8-1^ Wholly emerged. 16, 1 39 12 Venus passed the meridian. XXXI. An Account of Mr. Benjamin Franklins* Treatise, intitled. Expert- ments and Observations on Electricity, made at Philadelphia in America. By JVm. Watson, F.R.S. p. 202. Mr. Franklin's Treatise, lately presented to the Royal Society, consists of 4 letters to his correspondent in England, and of another part intitled, ' Opinions * Dr. Benjamin Franklin, one of the most celebrated philosophers and politicians of the 1 8th cen- tury, was born at Boston in North America, in the year 1706. His father was a tallow-chandler there, and young Franklin was taken from school at 10 years of age to assist him in that business. But after two years spent in this situation, he was apprenticed to an elder brother, then a printer in Boston, who in 1721 began to print a newspaper there j the copies of which our author was sent to distribute, after having assisted in composing and printing it. On this occasion, our young philoso- pher enjoyed the secret and singular pleasure of being the much admired author of many essays in this paper ; a circumstance which he had the address to keep a secret, even from his brother himself j and this when he was only 15 years of age. The frequent ill usage from his brother produced a separation between them, when our author, at 17 years of age, withdrew privately to New York, and thence to Philadelphia, where he worked with a printer a short time. Here he was much noticed by Sir Wm. Keith, governor of the pro- vince, who advised him to go to England to purchase printing materials, to commence the business on his own account in Philadelphia, promising to advance him the money, and send him letters of credit to London for that purpose. This promise however was never fulfilled, and Mr. F. was thus thrown upon London at 18 years of age, without either money, friends, or credit. He soon found employment however as a journeyman printer j and after continuing about 18 months in this station; he returned to Philadelphia in 1726, along with a merchant of that town, as his clerk. But his IQO PHILOSOPHIC A.L TKANSACTIONS. [anNO 1751. and conjectures concerning the properties and effects of the electrical matter arising from experiments and observations.' master dying the same year, be again applied to the printing business, and soon after set up a print- ing house himself. About the same time Mr. F. selected, and assembled together, a few youths like himself, of a literary and philosophical turn of mind, forming a club or society, to meet on certain days to converse on such subjects, to read books, and to write useful essays. Their collection of books gradually increased, and at length advanced to a public library. The other colonies, sensible of its advantages, began to form similar plans ; and hence originated the libraries at Boston, New- York, Charlestown, &c. ; that of Philadelphia having since become equal to any in Europe. About 1728 or 1729, young Franklin set up a newspaper in Philadelphia, which proved very pro- fitable, and otherwise useful, as affording an opportunity of making himself known as a political writer. He now became a public man ; his talents began to be generally known, and in consequence he was appointed successively to the offices of printer to the House of Assembly, clerk to the Gene- ral Assembly of Philadelphia, and post-master, and at length a member of the general assembly itself. In 1738 he formed the first fire-company there, to prevent and extinguish fires in houses, &c. also insurances from the same ; plans which still exist, and were soon imitated by other persons and in other places. In 1744, during a war between France and England, the French and Indians falling on the back settlements, by Mr. F.'s exertions a body of 10,000 volunteers were raised for their de- fence and security. Pursuits of a different nature next occupied his chief attention for some years. Being always much addicted to the study of natural philosophy ; and the discovery of the Leyden experiment in electri- city having rendered that science an object of general curiosity ; Mr. F. applied himself to it, and greatly distinguished himself in it. By his experiments he made a number of important discoveries and proposed ingenious theories to account for various phenomena ; which have since been generally adopted. His observations he communicated, in a series of letters, to his friend Mr. Collinson in England, by whom they were published; the first of which is dated March 28, 1747. In these he makes known the power of points in drawing and throwing off the electric matter, on which he afterwards founded his celebrated method of securing buildings from the stroke and damacre of thun- der and lightning, having previously proved experimentally the identity of electricity and the matter of lightning : on similar principles too he explained the aurora borealis. In the year 1749 he proposed a plan of an academy, to be erected in the city of Philadelphia, as a foundation for posterity to found a seminary of learning, more extensive and suitable to future cir- cumstances; and in 1750 three of the schools were opened, viz. the Latin and Greek school, the mathematical school, and the English school. This foundation .soon after gave rise to another more extensive college, incorporated by charter in 1755, which is now in a veiy flourishing condition. In this last year, when he returned to London, he met wiUi the greatest respect from all learned men: he was elected f.r.s., and had the honour of the Society's gold medal for his philosophical discoveries ; he had also the degree of doctor of laws conferred on him by different universities. But at this time, by reason of the war which broke out between England and France, he returned to America, and interested himself in the public affairs of that country, with most effectual benefit. In 1757 he was again sent to England as agent for the province of Pennsylvania, Massachusetts, Mary- land, and Georgia; after remaining here 5 years, he returned to America in 176"2, where he received public thanks for his faithful services. In 1764 he again returned to England as a provincial agent, where he remained many years. In 17(56 he was examined before the House of Commons relative to the state of America, particularly as to the stamp net, which was soon after repealed. But the troubles were now beginning, and the British government seemed resolved to accelerate rather than divert the storm. Dr. F. remained in Europe till 1775, and then returned to his native country. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. IQl- The 4 letters, the last of which contains a new hypothesis for explaining the several phenomena of thunder-gusts, have either in the whole or in part been before communicated to the k. s. It remains therefore now only to lay before the Society an account of the latter part of this treatise, as well as that of a letter, intended to be added to it by the author, but which arrived too late for publi- cation with iL This ingenious author, from a variety of well adapted experiments, is of opi- nion, that the electrical matter consists of particles extremely subtle, since it can permeate common matter, even the densest metals, with such ease and freedom, as not to receive any perceptible resistance. Electrical matter, according to him, differs from common matter in this, that the parts of the latter mutually attract, and those of the former mutually repel each other ; hence the divergency in a stream of electrified effluvia: * but that, though the particles of electrical matter do repel each other, they are strongly attracted by all other matter. From these 3 things, viz. the extreme subtilty of the electrical matter, the mutual repulsion of its parts, and the strong attraction between them and other matter, arises this effect, that when a quantity of electrical matter is applied to a mass of common matter of any size or length within our observation (which has not already got having first endeavoured in vain to dissuade the ministry from their coercive measures. His fame stood as high in the political as it had done in the scientific world. He became an active member of the new legislative assembly, and America is indebted for the formation of its constitution to this virtuous and enlightened philosopher. After this important service he was sent ambassador to France, to negociate an alliance with that country, in which he was completely successfiil. He also acted as one of the plenipotentiaries for his country in signing the treaty of peace with England in 1783. Two years after, he returned again to America, and received from his grateful countrymen those honours and distinctions which he had so justly merited. At length, after rendering to mankind the most essential benefits as a natural and moral philosopher, the infirmities of age and sedentary employments increasing fast upon him, he became more and more afflicted with the gout and the stone, till the time of his death, which happened the 17th of April 1790, at 84 years of age. To record Dr. Franklin's numerous discoveries and experiments, with the many useful institutions founded by his means, and the other curious transactions of his long and valuable life, would require an ample volume : and indeed a posthumous volume has been published, drawn up by himself, but containing only about half the term of his life ; which leaves a general wish that the remainder of such interesting memoirs may one day see the light. Dr. F. was author of very numerous tracts and essays on various branches of natural philosophy, as well as on politics and miscellaneous subjects, which have been published in different forms. His diction was easy, natural, and flowing; and his conversation at once amusing and instructive. His temper and manner lively, innocent, playful, interesting. His character leading and persuasive, not commanding. Among his playfellows, while a boy, be was always the captain, leader, and conductor ; among men o!' all descriptions, in maturer age, he was the life and soul of every com- pany. • As the electric stream is observed to diverge very little, when tlie experiment is made in vacuo, this appearance is more owing to the resistance of the atmosphere, that to any natural tendency ia the electricity itself. W. W. — Orig. 1Q2 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. its quantity) it is immediately and equally diffused through the whole. Thus common matter is a kind of sponge to the electrical fluid ; and as a sponge would receive no water, if the parts of water were not smaller than the pores of the sponge ; and even then but slowly, if there was not a mutual attraction between those parts and the parts of the sponge ; and would still imbibe it faster, if the mutual attraction among the parts of the water did not impede, soiijg force being required to separate them ; and fastest if, instead of attraction, there were a mutual repulsion among those parts, which would act in conjunction with the attraction of the sponge : so is the case between the electrical and common mat- ter. In common matter indeed there is generally as much of the electrical as it will contain within its substance : if more is added, it lies without upon the sur- face,* and forms what we call an electrical atmosphere ; and then the body is said to be electrified. It is supposed, that all kinds of common matter do not attract and retain the electrical with equal force, for reasons to be given hereafter , and that those called electrics per se, as glass, &c. attract and retain it the strongest, and con- tain the greatest quantity. We know that the electrical fluid is in common matter, because we can pump it out by the globe or tube ; and that common matter has near as much as it can contain ; because, when we add a little more to any portion of it, the additional quantity does not enter, but forms an elec- trical atmosphere ; and we know that common matter has not generally more than it can contain ; otherwise all loose portions of it would repel each other, as they constantly do when they have electric atmospheres. The form of the electrical atmosphere is that of the body which it surrounds. This shape may be rendered visible in a still air, by raising a smoke from dry resin dropped into a hot tea-spoon under the electrized body, which will be at- tracted and spread itself equally on all sides, covering and concealing the body. And this form it takes, because it is attracted by all parts of the surface of the body, though it cannot enter the substance already replete. Without this attrac- tion it would not remain round the body, but be dissipated in the air. The atmosphere of electrical particles surrounding an electrified sphere is not more disposed to leave it, or more easily drawn off" from any one part of the sphere than from another, because it is equally attracted by every part. But that is not the case with bodies of any other figure. From a cube it is more easily drawn at the comers than at the plane sides, and so from the angles of a body of any other form, and still most easily from the angle that is most acute ; and for this * The author of this account is of opinion, that what is here added, lies not only without upon the surface, but penetrates with the same degree of density the whole mass of common matter, upon which it is directed. — Orig. Vol. xlvii.] philosophical transactions. 1Q3 reason points have a property of drawing on, as well as throwing off the electri- cal fluid, at greater distances than blunt bo. creased heat, and again lays it down at the command of the will, is the immediate mechanical cause, by which the muscle does instantly contract, and is again re- laxed, at the command of the will. ^Tience it would appear that muscular voluntary motion is performed merely as a sensation, (Hartley Conjecturae de Sensu, &c.) extremely acute, and under the nicest management of the will ; which explains its velocity in a great measure. ^LVllI. An Account of the Eruption of Mount Fesuvius, Jrom its first Be- ginning to the 28th of October 1751, in a Letter from Mr. R. Supple, p. 315. TTiis communication is rendered unnecessary, 6rom a more particular account being grven at p. !245 of this volume. XL IX. Of the Lunar Eclipse which happened Nov. 21, 1751 ; observed by Mr. James Short, F. R. S. in Surry-street. p. 317. The weather was exceedingly tempestuous, and the sky overcast with clouds, 80 that the following times cannot be depended on to less than 2 minutes. Penumbra very visible at 7^ 58" 0» Beginning of the eclipse at. 8 6 O End of the eclipse at 11 6 O The quantity of this eclipse seemed about the middle to be larger than accord- ing to all the tables. The Transit of the moon over the meridian. Preceding limb passed the meridian at 12'' 5" 18* Subsequent limb passed the meridian at 12 7 50 Mr. Pound observed a similar eclipse at Wanstead, just two sarotic periods before this, and has described it in the Philos. Trans. N° 347, and makes the following remark, " This eclipse is the more considerable, as happening very near the moon's perigee, and therefore usefld to veri^' her anomaly ; as also to limit the greatest diameter of the shadow of the earth, and consequently the pa rallax of the moon. This may be very properly compared with that of the 19th of October 1697, whose middle was at 7"^ -Al" p. m. at London, and the quantity the same as now." It may be added to Mr. Pound's remark above, that this eclipse happened nearer to the moon's perigee, than that which he observed in the year 1715, and therefore more proper for verifying the moon's anomaly, and limiting the greatest diameter of the shadow of the earth. L. A Letter from the Reverend Father Augustin Hallerstein, of the Society of Jesus, Pres. of the Astron. Col. at Pehin in China, to Dr. Mortimer, Sec. R. S. Dated Pekin, Sept. 18, N. S. 1750. p. 31 9. This letter contains no real or usefiil information ; but only complaints of the missionaries' vrant of means and instruments and information, &c VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 221 LI. On Hernias with Sacks. By Mons. le Cat, F. R.S. Jrom the French, by Tho. Stack, M. D., F. R. S., p. 324. A Hernia by Rupture, having nevertheless a Sack. — In giving a private course of operations to his English pupils, on the body of a lad of 18 years old, M. le Cat discovered this hernia. The aponeurosis of the musculus obliquus extemus ran over the whole tumor, and entirely covered it. At the anterior and lateral internal part of this tumor was the ring lengthened into the shape of a perpen- dicular button-hole ; which had nothing to close it but a cellular lamina, which covered all this bag, being a continuation of the cellular membrana adiposa. Through this button-hole appeared the cellular coat, with which the peritonaeum furnishes the spermatic vessels. The intestine occupied the rest of this bag ; and at the bottom was contained the testicle, which consequently had never taken the way of the ring to come out of the belly, as it usually does ; but having passed on one side, it had gradually pushed out the aponeurosis of the musculus obliquus extemus ; and the intestine having followed it, and broke the true la- mina of the peritonaeum, they had in concert formed this elongation. At least this is the most natural explanation he could give of this singularity. That the testicles are originally in the belly, is a fact sufficiently known. He had dis- sected foetuses, in which he found them there, near the bladder. It is pretty common to feel them in the rings in children ; and he had found them there even in lads of upwards of 20 years old. A Hernia having Tico Sacks. — Continuing the above-mentioned course, he lOund in the body of a bachelor of 48 years of age, a rupture with a double herniary sack, the first of which was formed by the expansion of the aponeurosis of the obliquus extemus, as in the preceding observation, excepting that this expansion was only on the outer side, that the ring was in its usual place, that the bottom of the bag formed by this expansion had some empty spaces, where the expansion was wanting. In short, the bag was neither so complete, nor so thick as that of the foregoing observation ; but on the other hand, there was a 2d bag, formed as usual by the true lamella of the peritonaeum. Another Sort of Duplicity of the Herniary Sack. — A coachman about 65 years of age, had a rupture of long standing, of the strangulation of which he had al- ready cured him in 1 748. Having taken off his truss, in order to get it mended, he was seized with strangulation the IQth of Feb. 1750. After applying all the remedies prescribed in such cases without success, he was obliged to perform the operation on the 21st at 8 in the evening. Having laid the bag open in the usual manner, which contained a little watery humour, he was much surprized at discovering within this bag a second bag, or pocket, which could be nothing else, but either a second hemiary bag, or an incomplete hernia ; that is, a por- tion only of one side of an intestine elongated, and come down through the ring. The number of considerable blood-vessels on this pocket, its thickness and fibrous 222 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. texture seemed to evince the latter. But first, on pressing this bag, all its con- tents returned into the abdomen ; 2dly, the patient assured him, even at the in- stant, that his rupture had kept up since its reduction in 1748 ; and he found this bag adhering, not only to the first bag, but also attached by old and strong adherences to the testicle and spermatic vessels ; and it was impossible that this state should be the effect of 3 days of strangulation. However, as the patient might possibly have deceived him in his account ; and it was dangerous to open a bag which had too near a resemblance with the gut of an incomplete hernia, he came to a resolution, which equally suited the 2 suspected cases. He sepa- rated the testicle and spermatic vessels from this sack, and pushed back this pocket, or second bag, into the belly. The patient having died on the Qth day after the operation, they found that the pocket which had given them so much uneasiness, and which he had re- duced into the belly, was really a herniary sack formed by the true peritonaeum ; and therefore that the first sack must have been either an interior aponeurotic lamina of the abdominal muscles, or the cellular membrane thickened by the long duration of the hernia and its strangulations. The considerable thickness of the true or second sack renders this notion very probable. He says that the first sack must have been formed by an interior aponeurotic lamina, and not from an exterior one, like that of the first observation ; because, in this opera- tion, he had freed the ring, in his usual manner, above this first sack, and with- out opening it. Then he passed the grooved catheter over this sack, under the aponeurosis or pillar of the musculus obliquus externus : and therefore this sack could not be a continuation of this external aponeurosis, but that of some more inner lamina, or of the cellular membrane of the very peritonaeum, separated from the true lamina by the serosities which they found in it. Two other observations are subjoined : 1*/. A Natural Blind Duct, being a Production of the True Lamina of the Peritona-um by the Rings. — In the dead body of a woman, 46 years old, he found this duct of the thickness of a goose-quill, being a production of the true lamina of the peritonaeum stretched out by the rings ; of which Swammerdam and Nuck dispute the discovery, and Blancard denies the existence. What made him discover this, was, that its extremity was widened into the shape of a bubble as large as the top of a finger, and full of a watery humour. This woman had never had a hernia, nor even the least tendency towards one. 2d. Strictures and Carnosities in the Urethra. — Nothing is more common at this day than to hear people assert, that strictures and carnosities of the urethra are mere chimeras ; that the bodies of persons, who were thought to have these strictures and carnosities, had been opened, and that none of these had been found. He himself has made this observation, and he inferred thence, that there were urethras, in which a phlogosis, a fungous inflation gave occasion to VOL. XLVH.] PHILOSOPHICAL TRANSACTIONS. 223 the deception, being taken for strictures and carnosities : but if he had drawn this general inference, that of all the urethras, where these strictures and car- nosities are thought to be found, not one has any thing in them, he should have been deceived, and would now make his recantation. One of his boarders preparing to perform the operation of cutting on the dead body of a bachelor, aged 45, the sound could not pass ; the pupil forced, and made a false passage. Mr. le Cat opened this canal, and found, 1st, that a simple small stile could not pass into the urethra, by pushing it from the glans towards the prostate ; but that it passed, by pushing it from the prostate towards the glans ; 2dly, a little before the place, where the bulb becomes less thick, and begins to surround the urethra, that is, about a large finger's breadth from its beginning, there was a stricture entirely like that which Dr. Willis discovered in the upper longitudinal sinus of the dura mater ; 3dly, some few lines lower down was a caruncle, or a fleshy firm bump, of the size of a pea ; and below this bump, the urethra was extremely straightened ; 4thly, the basis of this camosity formed a kind of valve, and there he found the false passage, that went into the substance of the bulb. LII. On the Effects of Lightning at South-Moullon in Devonshire. By Joseph Palmer, Esq. p. 330. On Thursday June 6, 1751, about 3 o'clock in the afternoon, (that day, and some others before, having been extremely hot and sultry, and the wind pretty strong in the south-east) a flash of lightning, attended with an uncommon thunder-clap, which immediately followed or rather accompanied it, fell on the windows and walls of the church and steeple of South-Moulton in Devon, greatly damaging them. Many stones in the walls, &c. were broken and splin- tered in an extraordinary manner ; also much damage done to the bells and iron spindles, and the church clock stopped. In the adjoining fields the ground was much torn up, as if ploughed, and an oblique hole made of about 3 feet deep. LIIL An Improvement of the Bills of Mortality. By Mr. J. Dodson.* p. 333. There has lately been a scheme proposed for amending the form of the bills of mortality of London, in a pamphlet called " Observations on the Past Growth and Present Stite of London," by Mr. Corby n Morris, who has enumerated many excellent purposes to which it may be applied, but has omitted to mention * Mr. Dodson was an ingenious and very industrious mathematician, and the autlior of several use- ful books ; but we have found few or no particulars of his life. He was some time master of the Royal Mathematical School in Christ's Hospital, London. His publications chiefly were, 1. Anti- logarithmic Canon, folio, 1742. 2. The Calculator, a collection of useful tables, large 8vo, 174.7. 3. Mathematical Repository, being a collection of analytical questions and solutions, in 3 vols. Svo,, Ann. 1748, 1753, 1755. 224 MilLOSOPHlCAL TRANSACTIONS. [aNNO 1751. that of giving a greater degree of certainty to the calculations of the values of annuities on lives ; a benefit too considerable to be passed by silently. The pre- sent possessors of entailed estates are, in common law, justly called tenants for life. Marriage-settlements generally convey the reversion of a considerable part of the bridegroom's estate to the bride, for her natural life after his decease ; to which two things all the freehold estates in these kingdoms are liable : and if to these be added the great number of copyholds determinable on lives ; the great quantities of church, college, and other lands, leased on lives, and the estates possessed by ecclesiastical persons of all degrees ; we shall find that the values of the possessions and reversions, of much the greatest part of the real estates in these kingdoms, will one way or other depend on the value of lives. Likewise the incomes annexed to all places, civil and military, all pensions, and most cha- ritable donations, are annuities for life. The interest or dividends of many per- sonalities in the stocks have been, by the wills of their possessors, rendered of the same kind ; besides which, there are some annuities on lives which have been granted by the government, and have parliamentary security for their pay- ment ; and others that have been granted by parishes, in consequence of acts of parliament made for that purpose. After this summary view of the extensive property, vested in annuities on lives, it would be very easy to name a great variety of circumstances, in which the computations of the values of 1, 2, or more lives, will become necessary to those persons who do not chuse to have their property determined by customs which seem to have been established merely for want of good methods of calcu- lation. The advantages attending the determination of those things by calculation, rather than by custom, being therefore considered as evident, it may seem strange that, notwithstanding many of these tenures have subsisted from the very origin of private property in these kingdoms, yet we do not meet with so much as an attempt towards computing their values, till that of the late justly cele- brated Dr. Halley, by the assistance of the bills of mortality of Breslaw in Silesia, which was soon followed by Mr. De Moivre's truly admirable hypothesis, that the decrements of life may be esteemed nearly equal, after a certain age. It has been the opinion of some authors, that, since his hypothesis was originally de- rived from the Breslaw observations, it cannot be near so well adapted to the in- habitants of these kingdoms, as what has been derived from the bills of morta- lity of London. But this argument does not, Mr. D. conceives, appear to be conclusive; 1st, because those bills, as hitherto kept, are not well adapted to answer this purpose ; 2dly, because the manner in which the inhabitants of Lon- don, and those of most of the country towns and villages, live, their occupations, diet, and diversions, nay the very air they breathe, are as different, as those of VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 225 Lonclon and Breslaw can possibly be ; and consequently so must the times of their dissolution. All which has been, with a great deal of clearness, evinced by the gentleman above quoted ; 3dly, because those persons who suppose that Mr. De Moivre's hypothesis has its foundation peculiarly in the Breslaw obser- vations, are greatly mistaken : for Mr. D. having lately been endeavouring to discover some further helps to the speedy valuation of lives, he found that, on the contrary, if tlie London observations had been then in Mr. De Moivre's hands, he might as justly have derived his hypothesis from them. For the same thing, which Mr. De Moivre mentions, concerning the equal annual decrease in a certain number of persons, happens in the table of the Lon- don observations ; and the like happens in other instances, to be met with in the London observations, as published by different authors. Add to this, that having calculated the value of an annuity on a life of 10 years of age, by both tables, and also by the hypothesis, Mr. D. finds it to turn out thus : By the Breslaw tables of observations 17-7237 years purchase. By supposing the decrements of life equal. . . , 16.8814 By the London tables of observations , 16.3907 From which there seems to be some reason to conclude, that the hypothesis (as it gives an answer less than the Breslaw, and greater than the London obser- vations) may be the best method of the three. And it is further remarkable, that the result by the hypothesis, is nearer to that by the London, than to that by the Breslaw observations. However, if the argument for using the London observations has any force at all, the computation of the value of each person's life must be made from observations drawn from the bills of mortality, kept at the place of his or her residence : and therefore it is, that Mr. D. contributes as much as he can, to preserve a sufficient number of good bills of mortality. There seeins to be an objection, both to the hypothesis, and to the observations ; for it is well known that females, especially at two periods of their life, are ob- noxious to fatal disorders not incident to the other sex, nor distinguished in the present bills of mortality ; and consequently neither the tables of observations nor the hypothesis (which is derived from them) will render the calculations of the values of lives sufficiently certain ; unless there be a periodical distinction of sexes in those bills : as it would probably appear, if such a distinction had been introduced, that there is a wide difTerence between the values of a male and fe- male life of the same age. But there will be a great inconvenience, in rejecting the hypothesis, which none of these gentlemen have remedied ; viz. the prolix and laborious compu- tation hitherto directed for finding the values of lives from tables of observations; whereas, by the hypothesis, as its author justly observes, more can be con- VOL. X. G G '226 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. eluded in a quarter of an hour, than can be performed in a quarter of a year, by any method which the others have demonstrated. Whence it may be pre- sumed, that the hypothesis will continue to be used, till better methods are substituted instead of those derived from it. When the bills of mortality digested into a proper form, shall have been kept a convenient time in every city or considerable town, and also in every hundred, or other proper division of the country ; then, and not till then, the hypothesis may be tried by the facts that will appear from the bills, and be confirmed or re- jected accordingly. Indeed Mr. D. is almost persuaded, from what has been above remarked, that the hypothesis will, in general, appear to be the nearer the truth, the more those bills of mortality shall be in number, and the correcter they are kept. He proceeds therefore to mention those alterations which he thinks may be of advantage, in the form of the bills of mortality, in every part of these kingdoms, over and above those mentioned by Mr. Morris, in the before-quoted pamphlet. J . That there be a distinction made on the face of the bills of mortality, between the persons who were born in the place where such bills were kept, and those that were not. This will be effected with a very little trouble, if the searchers of each parish be instructed to ask the question of the friends of the deceased, and annex the answer to their report. This precaution will facilitate many of the good purposes proposed by Mr. Morris ;' and particularly with re- gard to fixing the values of lives, it will enable the persons who shall apply the bills to calculation, to draw their conclusions only from the lives that were both begun, and ended, in or near the same place ; the want of the possibility of doing which is the principal objection to the London bills, as hitherto kept ; 2, that there be a distinction, with regard both to age and disease, made on the face of the bills, between the sexes ; and that one case be added to the list of diseases ; viz. complaints peculiarly incident to the female sex. This will not only solve the difficulty above started, but also answer many purposes in political arithmetic, as well as to the sagacious physician ; 3, that a further division be made in time ; for whereas Mr. Morris's scheme exhibits no age between 40 and 50, Mr. D. proposes, that the numbers dying between 40 and 45, and between 45 and 50, should be particularized in the bills ; the design of this being to fix the periods that are fatal to the fair sex, with more certainty. These alterations, together with those proposed by Mr. Morris, being made, the yearly bill of mortality for London, will appear as in a specimen which Mr. D. annexed, and according to which form nearly such tables are often kept. VOL. XLVir.] PHILOSOPHICAL TRANSACTIONS. 227 Hl^. Concerning the Dissection nj a Rupture. By Mons. Le Cat. Translated from the French, by Tho. Stacli, M. D., F. R. S. p. 341. Mr. le Cat here mentions, that when he sent the remarks on the singular hernia of Catherine Guillematre, (Phil. Trans. N". 46o) he had already made some fruitless attempts to cure her, but had not then lost all hopes of success. He imagined, that a long use of emollient cataplasms might restore suppleness to the intestine which constantly kept out of the belly, and was turned inside out, because it was the portion continuous to the cascum, colon, rectum, and anus, which could be of no use, but much incommoded the patient by this ex- traordinary situation. But all his trials were of no avail, though they were car- ried so far as to render this gut quite bloody : its long exposure to the air made it become too thick and hard ; and at the same time so robust or insensible, that all these vigorous applications made no bad impression on the rest of the animal economy. In fine, Catherine Guillematre quitted the hospital without any other benefit but that of having afforded M. le Cat and his colleagues an opportunity of instructing themselves. From that time he had no news of this woman till the 6th of May, 1750; when he was informed, that her body actually lay in the dead ward, and that she died in the hospital of old age and a broken constitution, as much as of any disease. He was extremely curious to embrace this opportunity of having ocular de- monstration of the probable conjecture, which he had made in this woman's life- time, and a confirmation of his having solved the enigma arising from this sin- gular hernia ; which, on opening the body, was accordingly confirmed. Lf^. //« Account of Dr. BohadscKs Treatise, communicated to the Royal So- ciety, entitled Dissertatio Philosophico-Medica de Utililate Electrisationis in Curandis Morbis, printed at Prague., 175 J . Extracted and translated from the Latin by Mr. Wm. fVatson, F.R.S. p. 345. The author of this treatise, Dr. Bohadsch, was a Bohemian, a very learned gentleman, who, while he was in England about 2 years before, was frequently at the meetings of the r. s., and was very conversant with, and much esteemed by many of that body, from whom he received very great civilities. He was more particularly taken notice of by his grace the late Duke of Richmond, whose loss we yet lament. This treatise, from its title, promises only an account of the advantages of electrization in medicine: but this is not the whole of which it treats ; it exhibits also a series of observations of the effects of electricity on both solid and fluid bodies, on animals in a state of health, as well as on the distempered. GO 2 / 228 PHILOSOPHICAL TKANSACTIONS. [aNNO 1751. Our author first takes notice that electricity, being continued for some hours, lessens the weight of the body electrified. He exemplifies this first on fluid bodies ; two equal portions of which, before electrizing, he accurately weighs ; and then the diflference between these 2 portions, one of which has been electrized between 4 and 5 hours, and the other, though in the same room, not electrized at all, is attributed to the operation of the electric eflfluvia, viz. 4 oz. of river water exposed in a glass vessel of 4 inches diameter were electrized 5 hours, and lost in their weight 8 grains. But 4 oz of river water, in the same kind of glass, but not electrized, lost in the same time only 3 grains. And so of other fluids, less or more. Also each lost more by electrizing in a tin vessel, than in a glass one. When the vessels were narrower, all the fluids lost proportionally less. And when the opening was nothing, or close stopped, the evaporation was no thing by electrization. Hence our author concludes, 1 . That electricity augments the natural evapo ration of liquors, unless those of a viscous kind, as oil of olives, which from their tenacity lose nothing of their weight. 2. That electricity increases the evaporation of liquors in proportion as they are more or less volatile. 3. That electricity operates most in those vessels, which are most permeable to its efliu- via, viz. in vessels of metal more than those of glass. 5. That the effects of electrizing are not observed in vessels closely stopped. He afterwards put to the trial several substances of a more solid form. And from these experiments he observes, that the electricity diminishes the weight of solid bodies, only if these are impregnated with humours liable to evaporate : and therefore it is only on the fluids in them that the electricity operates. Dr. B. then exhibits some experiments made by persons of credit, to discover, whether electricity would accelerate the growth of plants ; and from several trials he found that it did. There then follows a series of experiments, which prove, that electricity augments the transpiration of animals. He proceeds to give a theory of those distempers in which electricity seems to have the greatest eflects. He confines himself however more particularly to the hemiplegia ; of which dis- temper he gives the history, corresponding with what we find in the best medical writers. He likewise gives the usual method of cure, and shows that the at- tempts of relieving this malady by electricity, nearly square intentionally with the remedies most celebrated in practice. That the electrical sparks and commotion produce the same efifect, though in a more powerful manner, as warm sulphu- reous baths, frictions, sinapisms, stinging with nettles, &c. generally made use of in the cure of this distemper. This reasoning does very well in theory ; but Mr. W. would have been glad to have seen it justified by practice, and his own observations. But instead of these, our author contents himself with giving over VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 229 again the lying stories of Pivati, &c. He finishes this dissertation, by deducing several conclusions from what he has premised, which are as follow : 1. That electricity may be advantageously applied to medicinal purposes. 2. That it augments the natural transpiration of animals. 3. That this acceleration of transpiration in men is through the exhaling capillary vessels, and not through the subcutaneous glands. 4. That the nervous fluid may be called the electrical fluid. 5. That the nerves subservient to sensation are not different from those subservient to motion. 6. That the immediate cause of the hemiplegia is the immeability of the nervous fluid through the nerves. 7. That of all other dis- tempers the hemiplegia seems most properly the object of electricity. 8. That it may be of use also in intermitting fevers. Q. That a palsy in the left side of the body is owing to the right side of the brain, and vice versa. 10. That anger, the parent of immerous evils, is sometimes useful to paralytics. ] 1. That as long as the paralytic limbs are rigid, it is an argument, that the bursal ligaments of the joints, and the sheaths of the tendons, are deficient in the fluid adapted by nature for their lubrication. 12. That every species of palsy does not arise from • the nerves being either obstructed or compressed. Lf^I. Of a Horizontal Top. invented by Mr. Serson By Mr. James Short, F.R.S. p. 352. , The horizontal top, the invention of Mr. Serson, who was unfortunately lost in his majesty's ship the Victory, is pretty well known. This ingenious person found, that when this top is set a going in the proper way, its upper side, which is polished, about 2 minutes after it was set up, moved in such a manner, as to give a true horizontal plane ; and that this plane was not at all disturbed by any motion or inclination you give the box, in which it is placed, and therefore might be proper to be used aboard a ship ; by which means seamen might be enabled to take the altitude of the sun or stars, in order to find their latitude, even though they cannot see the horizon in thick hazy weather. Some gentlemen were of opinion, that the air had some share in the cause of this horizontality. Mr. Short therefore applied to Mr. Smeaton, who had the best air-pump he ever saw, all of his own invention and construction. Having set the top a going, they put a receiver over it, and immediately exhausted the air. By repeated trials it had been found that the top, when set a going in the open air, played or spun during the space of 35 minutes of time, from the instant of its being set up till it had lost the circular motion : but they found, that in the exhausted receiver it playal or spun during the space of 2 hours \6 minutes, preserving a perfect horizontality for the space of 4 of an hour ; and therefore, that the air has no share at all in the cause of its horizontality, but that the air is a great impediment to its motion. 230 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. LVII. Observations made in going up the Peak ofTeneriffe. By Dr. Thomas Heberden, and communicated by IVm. Heberden, M.D., F.R.S. p. 353. At 1 o'clock in the afternoon they set out from the villa or town of Orotava, about 6 leagues distant from the peak of Teneriffe. The weather was cloudy ; and before they had travelled quite a league, they found themselves surrounded by a very thick mist or fog, which lasted about a league : all which time they travelled among gardens and woods of pine-trees, after which they came to an open country ; the soil very dry ; here and there a single pine-tree, and some few Spanish broom-plants ; some loose stones, as large as a butt ; others, which seemed to have been burned, and are supposed to be cast out from the volcano of the peak. The sky very clear, and the thick mist, which they had passed through, now seemed a sea of ash-coloured clouds below them. Having tra- velled 1 leagues on this soil, they arrived at 8 o'clock in the evening at the Falda del Pico, or foot of the peak. Here they we;-e obliged to leave their horses ; the road, by reason of its steepness and loose sandy soil, being impassable to them. At half a league's distance they baited under some large rocks, called La Estancia de los Ingleses, or the English baiting-place, being first used as such by some of our countrymen in ascending the peak. Here they rested all night, making fires to temper the air, which they found very cold. When the morning drew near, they proceeded on their journey, ascending for a quarter of a leao-ue the same soil (but more steep and loose) till they arrived at some large rocks of mal- payses (or stone burnt by a volcano) ; among which, as the ground was more firm, they walked with less trouble, or rather climbed, being frequently obliged to make use of their hands to help them forward. Having gone about a quarter of a league in this manner, they arrived at the famous cave of Teyde. It is sur- rounded on all sides (or rather buried) with large mal-payses, orvolcanian rocks, between which you discover the entrance about 6 feet high, and 4 feet wide. The cave seems to be about 15 feet wide at the entrance; the extremity they could not discover. From its entrance to the surface of the water, which covers the bottom, seems to be about 12 or 14 feet. The top and sides of the cave are of smooth stone. The bottom is covered with ice or snow ; above which is a body of water about half a yard deep. This cave is the grand reservoir of snow of the island, whence they are supplied, when their common reservoirs, which they prepare for cooling their liquors, fail them. At somewhat more than a quarter of a league's distance from the cave, they came to a plain of sand ; from the middle of which arises a yellowish pyramid of sand or cinders, which the inhabitants call La Pericosa, and we the Sugar-loaf; around the base of which perspire vapours incessantly. The sugar-loaf is about an 8th part of a league to the top, which \%. very difficult of ascent, occasioned VOL. XLVII.] VHILOSOPHICAL TRANSACTIONS. 231 by the loose soil, and steepness of the road. About 8 o'clock, in the morning they gained the summit or caldera. It is about 12 or 15 feet deep: the sides, sloping down to the bottom, form a concavity, or crater, resembling a truncated cone, with its base uppermost. The crater seems nearly circular; its diameter about 40 fathom. The ground is very hot; and from near 20 spiracula, as from so many chinmeys, \ou perceive a smoke or vapour of a strong sulphureous smell. The whole soil seems mixed or powdered with brimstone, which forms a beautiful coloured surface. One of the rocks forms a sort of vault or nich ; against which the vapour con densing produces what the inhabitants call azufre de gota, or drop brimstone. The nich, against which the vapour is condensed, is of a greenish colour, spark ling with yellow like gold. The same colour you perceive on almost all the stones thereabout. A small part of the Sugar-loaf is white like lime ; and there is another less part, whose internal substance seems a sort of red clay, and whose superticies is covered with a salt. In the middle of one of the rocks was a hole, about 2 fingers breadth in dia- meter, whence proceeded a noise like a great body of liquor boiling very strongly; and one of the company burnt his hand by applying it to the spiraculum at 4 of a yard distance. This Sugar-loaf is covered with snow the greatest part of the year. The snow was lying on it from October 1742 to June 1743. The different accounts of various authors concerning the height of this famous peak would have induced one less inquisitive than Mr. H. to satisfy his curiosity, by examining its real altitude : for which end, between 3 and 4 o'clock in the afternoon of a very serene day, when not a cloud appeared, either on the sum- mit, or in the whole atmosphere, (to prevent any accidental refraction) having pitched on a plain along the sea-side for a horizontal stand, and measuring tri- gonometrically a base sufficiently corresponding to the angles with the greatest accuracy, he observed the height to be 2566 fathoms, or 3 miles, wanting only 74 fathoms. Two subsequent observations by himself, as well as 2 ante- cedent ones some years before by John Crosse, Esq. the British consul, served only to confirm his opinion of the justness of this observation. Though the body of the mountain is covered with clouds, the peak is gene- rally seen above them quite clear ; but sometimes the contrary happens ; the whole body of the mountain without a cloud, and only the summit of the peak covered with a thick white cloud, as with a cap. This is often observed in the finest weather ; when the Spaniards say, El Pico tiene su sombrerillo puesto ; i. e. • The Peak has put his little hat on ;' and think it a certain sign of rain. During 6 or 7 years, that Dr. H. lived in the villa of Oratava, as he had a continual sight of the peak, he several times observed the above phenomenon, and did not remember one instance in which the prediction of rain failed. 232 PHILOSOPHICAL TRANSACTIONS. [anno 1751. LFIIl. Observations of the Weather in Madeira, made by Dr. Thos. Heberden, and communicated by Wm. Heberden, M.D., F.R.S. p. 357. The thermometrical observations are made with Fahrenheit's thermometer, and the calculations deduced from 2 observations daily ; at 7 o'clock in the morn- ing, and at 3 in the afternoon. The same method of calculation is to be under- stood of the barometer. The rain fell through a funnel J 5 inches in diameter. The Lestc, Levant, or hot winds, are very troublesome. The remedy is, to keep within doors. October 1749, comparing 2 of Fahrenheit's thermometers together, one of them exposed on the north side of his house to the open air, the other within doors, the difference was as follows: Hour, Lest6, Oct, 20, 10, 12, 4 Madeira, Anno 1749. Therm, within-doors. 73, 7^, 77 Therm, exposed to the air. 81,82,77 Anno 1750. Barometer. 1 Thermometer. Barometer. Thermometer. | Mean Greatest ' Least M. H. G. H L. H. Mean Greatest Least M- H- G. H L H Height. Height Height. Height. Height. Height. Jan. 29.195 29-8 29.4 64. 68 62 Feb. 29.692 2975 29-5 63.8 Gl 61 March 29.81 30.2 29.8 64.66 70 61 29.12 29.65 29-3 66.5 71 61 April 30.075 30.2 I29.8 60.7 68 64 29285 29.4 29.1 66.45 68 65 May 2955 30.1 29.6 66.53 ii9 65 29-775 299 29-5 66.25 68 65 June 30.017 30.15 29.75 68.75 72 64 29.875 30.1 29-5 69.06 72 6 July 30.027 30.1 2995 74.58 75 72 29.887 29-95 29-8 73. 75 71 Aug. 30.013 30.1 29.95 75.07 77 74 29.386 30.1 29-75 75.4 78 72 Sept. 30.054 30.15 29.85 76.53 78 72 29.915 30.05 29-7 74.93 77 72 Oct. 29.841 30. 29.7 72.2 77 68 '29797 29-9 29-5 73.87 77 70 Nov. 29.68 30. 29.55 68.6 73 I37 29.875 30.05 29-55 70.825 76 67 Dec. 29.675 29-9 129.4. 164.9 68 62 29-843 30.2 29.7 66.27 74 64 An Account of the quantity of Rain, which has fallen in the Island of Madeira. The Years 1749 and 1750, were such dry years, that the corn was destroyed, and the fruit-trees suffered much, particularly the peach-trees, the fruit either falling to the ground while green, or, if it remained longer on the tree, being full of white worms. Anno 1747. 1748. 1749. 1750. Inch Dec. Inch Dec. Inch Dec. Inch Dec. January 20.525 8.600 2.097 7.150 February .485 10.958 1.203 1.771 March 4.339 5.241 932 1.123 April .528 .722 .777 .039 May .353 5.290 1.087 June 1.321 .420 .113 .226 July .200 .176 August .018 2.700 .003 September .540 .810 .855 1.682 October .010 3.303 1.512 6.601 November 5.181 2.654 3.059 5.611 December 7.351 1.500 6.527 1.882 Totals 40.851 37.508 22.365 27.351 VOL. XLVII.T PHILOSOPHICAL TRANSACTIONS. 233 LIX. Extract of a Letter from Mr. fVillem Fan Hazen to Mr. Philip Miller, F.R.S. concerning the Quantity of Rain, which fell at Leyden in the Year 1751. p. 360. During the course of the year 1751, it rained at Leyden no less than l63 days ; and the quantity of rain which fell was 4 ] inches. LX. Of a Double Child. By Thomas Percival, Esq. p. 36o. This uncommon child was born January 1732, at Hebus near Middleton, 5 miles from Manchester. The child, or children if they may be so called, are both females. The one is a perfect healthy looking fine girl. The imperfect one adheres to the perfect one by the cartilago ensiformis, by a cartilaginous substance 4 inches in circumference. The body seems to be of a soft fleshy sub- stance of very little regularity : it has no head nor neck, nor any respiration : from the upper parts of its body come out two short arms. , On the right, which is the longer, are 4 fingers, but no thumb ; on the left, which is very short, its hand is very deficient, and on it are only 2 fingers. The thighs, legs, and feet, are the most perfect, though the legs have only one bone in them. It has no vertebrae of the back or loins. The os sacrum, as well as the os pubis, imperfectly ossified. All its joints are very rigid and stiff. It has no anus, but passes off its water in the natural way. Its sternum is very imperfect ; and it has no clavicula. It seems insensible of pain, not removing its arms or legs, if laid in an uneasy posture. LXI. On the Phenomena of Electricity in Vacuo. By Mr. fVm. ffatson, F.R.S. p. 362. From a comparison of experiments in electricity made in vacuo, with those already made in open air, it appears that our atmosphere, when dry, is the agent by which, with the assistance of other electrics per se, we were enabled to accu- mulate electricity in and upon non-electrics ; that is to communicate to them a greater quantity of electricity than these bodies naturally have. That, on the removal of the air, the electricity pervades the vacuum to a considerable distance, and manifests its effects on any non-electric substances, which terminate that vacuum ; and that by these means, originally-electric bodies, even in their most perfect state, put on the appearance of non-electrics, by becoming themselves the conductors of electricity. The experiments treated of in this paper must be considered to have been made in a vacuum by Mr. Smeaton's air-pump, that rarefies lOOO times. The elec- trical machine, with its prime conductor, need here no particular description ; but that of the glass, in which the vacuum was made, should be more minutely VOL. X. H H 234 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. considered. It consisted of a glass tube nearly 3 feet in length, and of almost 3 inches in diameter. A ring of brass, exactly fitting this tube, was cemented to both its extremities, into each of which was screwed a hollow brass cap, nearly of an hemispherical figure. Into the top of one of these caps was adapted a brass box of oiled leathers, through which was admitted a slender brass rod of a length sufiicient to reach within 8 inches of the other extremity of the tube. Into the top of the other brass cap was fastened a brass rod, like the former, only of 8 inches in length. Thus the extremity of one of these brass rods might at pleasure, with- out letting in the air, be made to touch the other ; and for the better observing what difference in effect would arise from an increase of surface, a small brass circular plate was made to screw into each of these extremities. The intent of being able to bring the extremities of these rods near together, and to separate them again to what distance you pleased, was, that it might without difficulty be determined, whether, and to what distance, the electrical fluid would ma- nifest itself in vacuo, farther than in air of the same density with the external. The tube then thus fitted, and made dry both within and without, was placed in a cylinder of brass, of about 2 inches long, and of a diameter just sufficient to admit the brass cap before mentioned ; and round the rim of this brass cylinder, to prevent the ingress of air, was adapted a narrow piece of wet leather. These being placed on the plate of the air-pump, which stood upon cakes of wax, a piece of wire passed from the prime conductor to the long brass rod, at the other extremity of the tube, and by these means, on setting the electrical machine in motion, the long brass rod in the tube was electrified. When the brass plate at the bottom of this rod was placed near, or even at the distance of 2 inches from the plate of the other rod, the brushes of electrical fire were seen passing from the periphery of the upper plate to that of the lower, and every part of the air pump snapped on the touch of any one standing on the floor, and gave the other usual signs of the accumulation of electricity. But, as these plates were made to recede from each other, this effect grew less and less ; so that when they were removed 5 or 6 inches from each other, no snaps could be drawn from the air- pump ; as the dissipation of the electric fluid was now as easy from every part of of the prime conductor, as from the upper brass plate in the tube. On exhausting this tube, and electrizing as before, the air-pump still standing upon cakes of wax, the electrical fire was not only seen to pass from one plate to the other at the distance of 5 inches, but the same effect ensued at the greatest distance, to which in the tube the brass plates could be drawn. Being therefore desirous to see a further effect, and to avail himself of the whole length of this tube, Mr. W. took from the inside of it the short brass rod, to which the lower brass plate was fixed, and fastened this plate at the very bottom of the tube into V. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 235 the cap. The consequence was, that the electricity, meeting with scarcely any resistance, passed from the top to the bottom of the tube, and electrized the air- pump as before : and it was a most delightful spectacle, when the room was dark- ened, to see the electricity in its passage; to be able to observe, not, as in the open air, its brushes or pencils of rays an inch or 2 in length, but here the co- ruscations were of the w hole length of the tube between the plates ; viz. 32 inches, and of a bright silver hue. These did not immediately diverge as in the open air, but frequently, from a base apparently flat, divided themselves into less and less ramifications, and resembled very much the most lively coruscations of the aurora borealis. At other times, when the tube has been exhausted in the most perfect man- ner, the electricity has been seen to pass between the brass plates in one con- tinued stream of the same dimensions throughout its whole length ; and this, with a subsequent observation, seems to demonstrate, that the cause of that very powerful repulsion of the particles of electrical fire one to the other, which we see in open air, is more owing to the resistance of the air than to any natural tendency of the electricity itself; as we observe that its brushes from blunt bodies, when the electricity is strong, diverge so much, as to form, when seen in the dark, an almost spherical figure. This figure seems therefore to arise from the electricity's endeavouiing to insinuate itself between the particles of air. The figure that an elastic fluid of less density must form, when let loose, and equably compressed by one more dense and more elastic, must necessarily approach to that of a sphere. On admitting a very small quantity of air into the tube, these phenomena dis- appeared ; not so much from the small quantity of air admitted, as from the vapours which insinuated themselves with it. These lined the sides of the glass, and conducted the electricity imperceptibly from one end of the tube to the other. These experiments seem to evince, that however great the vacuum could be made, the electrical coruscations would pervade it through its whole length. Hence it appears that our atmosphere, when dry, is the agent by which we are enabled to accumulate electricity on non-electrics: as in the experiment before us, on the removal of it, the electricity passed off into the floor through a vacuum, of the greatest length we have hitherto been able to make, became visible in this vacuum, and manifested itself by its effects on the air-pump, being the non-electric substance, which terminated that vacuum ; whereas, when the air is not taken away, the dissipation of the electricity is from every part of the prime conductor. We see here also, contrary to what we have found hitherto, that an originally-electric body, viz. a dry glass tube, puts on the appearance of HH 2 236 PHILOSOPHICAL TRANSACTIONS. [aNNO]751. a noii-electric, by becoming itself the conductor of electricity, that is, by its keeping out the air, and suffering the electricity to pervade the vacuum. Mr. W. was desirous of knowing, for the further illustration of his proposi- tions, whether the Leyden experiment could be made through the vacuum. For this purpose he made the before-mentioned exhausted tube part of the circuit, so necessary to this experiment. In this experiment it is absolutely necessary that the whole quantity, or nearly so, of the accumulated electricity, should be dis- charged in the same instant of time. Accordingly on making the experiment, at the instant of the explosion, a mass of very bright embodied fire was seen to jump from one of the brass plates in the tube to the other ; but this did not take place when one of the plates was farther distant from the other than 10 inches. When the distance was greater, the fire then began to diverge, and lose part of its force ; and this force diminished in proportion to its divergency, which was nearly as the distance of the 2 plates. The difficulty however of applying the Torricellian vacuum to these experi- ments has been happily got over by Lord Charles Cavendish, our worthy vice- president. This noble lord, who to a very complete knowledge of the sciences joins that of the arts, and whose zeal for the promotion of true philosophy is exceeded by none, has applied it in the following manner, and his lordship put his apparatus into Mr. W.'s hands. This apparatus consisted of a cylindrical glass tube of about -^ of an inch in diameter, and of 7-^ feet in length, bent somewhat like a parabola in such a manner, that 30 inches of each of its extre- mities were nearly straight, and parallel to each other, from which an arch sprung, which was likewise of 30 inches. This tube was carefully filled with mercury ; and each of its extremities being put into its basin of mercury, so much of the mercury ran out, until, as in common barometrical tubes, it was in equilibrio with the atmosphere. Each of the basins containing the mercury was of wood, and was supported by a cylindrical glass of about 4 inches in dia- meter, and 6 inches in length ; and these glasses were fastened to the bottom of a square wooden frame, so contrived, as that to its top was suspended by silk lines the bent tube filled with mercury ; so that the whole of this apparatus with- out inconvenience might be moved together. The Torricellian vaccuum then occupied a space of about 30 inches. In making the experiment, when the room was darkened, a wire from the prime conductor of the common electrical ma- chine communicated with one of the basins of mercury, and any non-electric touching the other basin, while the machine was in motion, the electricity per- vaded the vacuum in a continued arch of lambent flame, and as far as the eye. could follow it, without the least divergency. That the electricity was not furnished from the glasses employed in these ope- A OL. XLVII.] PHILOSOPHICAL TRANSACTIONS, 237 rations, nor from the circumambient air, Mr. W. had heretofore, in his com- munications on this subject, endeavoured to evince. He had shown, that elec- tricity is the effect of a very subtil and elastic fluid, occupying all bodies in con- tact with the terraqueous globe: and that every where, in its natural state, it is of the same degree of density; and that glass and other bodies, which we deno- minate electrics per se, have the power, by certain known operations, of taking this fluid from one body, and conveying it to another, in a quantity sufficient to be obvious to all our senses ; and that, under certain circumstances, it was pos- sible to render the electricity in some bodies more rare than it naturally is, and by communicating this to other bodies, to give them an additional quantity, and make their electricity more dense; and that these bodies will thus continue until their natural quantity is restored to each ; that is, by those, which have lost part of theirs, acquiring what they have lost; and by those, to which more has been communicated, parting with their additional quantity. Both one and the other of these is, from the elasticity of the electric matter, attempted to be done from the nearest non-electric: and when the air is moist, this is soon accomplished, by the circumambient vapours, which here may be considered as preventing in a very great degree our attempts to insulate non-electric bodies. But these matters he had copiously treated of in his former communiaitions on this subject. If therefore the beforementioned principles are true, and if the electricity is not furnished by the globe in its rotation, nor by the air, it ought to be visible in the vacuum of the before-described glass tube, in its ingress to the frame of the electrifying machine, if this machine, and the man who turns its wheel, are supported by electrics per se; and if, during this operation, the electricity, as fast as furnished, is taken off by a bystander, or otherwise, from the prime con- ductor; as under these circumstances the vacuum is the only passage open to its progress, and from its elasticity the electricity should protrude itself through it. And from experiment this is the case; for on a piece of wire being connected with the end of the long brass rod, or with the brass cap at the upper extremity of that tube, and the other end of the wire fastened to any part of the frame of the electrifying machine, and this last put in motion, the electrical coruscations • are seen to pass as before, from one of the brass plates contained in the tube to the other ; and to continue, unless the air insinuates itself, as long as the ma- chine is in motion. If, under these circumstances, the hand of a person stand- ing on the floor be brought near the sides of the glass, the comscations will direct themselves that way in a great variety of forms, extremely curious to behold. This experiment therefore, in which the electricity is seen, without any preter- natural force, pushing itself on through the vacuum by its own elasticity, in order to maintain the equilibrium in the machine, which had lost part of its 238 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. natural quantity of electricity by the present operation. Mr. W. considers as an experimentum crucis of the truth of the doctrines here laid down; viz. not only that the electricity is furnished by those bodies hitherto called non-electrics, and not by the electrics per se;* but also, that we are able to add to, or take from, that quantity of electricity, naturally adherent to bodies. By what denomination shall we call this extraordinary power .!■ from its effects in these operations, shall we call it electricity ? from its being a principle neither generated nor destroyed; from its being every where and always present, and in readiness to show itself in its effects though latent and unobserved, till by some process it is produced into action, and rendered visible; from its penetrating the densest and hardest bodies, and its uniting itself to them, and from its immense velocity; shall we, with Theophrastus, Boerhaave, Niewentyt, Gravesande, and other philosophers, call it elementary fire.'' or shall we, from its containing the substance of light and fire, and from the extreme smallness of its parts, as passing through most bodies we are acquainted with, denominate it, with Rom- berg and the chemists, the chemical sulphureous principle, which, according to the doctrines of these gentlemen, is universally disseminated? We need not indeed be very solicitous in regard to its denomination; certain it is, that the power we are now treating about is, besides others, possessed of the properties before-mentioned, and cannot but be of very great moment in the system of the universe. LXIL Extracts of Father Augustin Hallersteins Astronomical Observations made at Pekin in 1746 and 1747 . By Dr. Bevis. p. 376. These are observations of the appulses and occultations of the planets and fixed stars, made by the Jesuits at Pekin. They are not made with much accu- racy, and are now of little or no use to science. * Since the communication of this paper to the Royal Society in February 1752, viz. in the suc- ceeding summer, the truth of this doctrine is put out of all doubt by the discovery made in France, in consequence of Mr. Franklin's hypothesis, of being able, by a proper apparatus, to collect the electricity from the atmosphere during a thunder-storm, and to apply it to the usual experiments, which demonstrates, that the matter of thunder and lightning and that of electricity are one and the same. That the electricity did not proceed from the glass, or other electrics per se, as they had been usually called, Mr. W. first discovered in the year 1746'. See Phil. Trans, vol. xliv, p. 713, and explained further vol. xlv, p. 9^, et seq. and though the electric matter may be taken from the atmosphere during a storm of thunder, or even when it is only charged with what are usually called thunder clouds, that is, when the atmosphere is replete with heterogeneous phlogistic matter, yet it must not be considered as coming from pure dry air, which, as I before mentioned, I conceive to contain in its natural state scarcely any of the electric matter, and is the agent, by which we are en- abled to communicate electricity to other bodies. — Orig. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 239 LXIII. Extracts of several Letters of Mordacb Mackenzie, M. D. concerning the Plague at Coiistantinople. By Dr. Clephane, F. R. S. p. 384. Before he transcribes his friend Dr. Mackenzie's letters relating to the late plague at Constantinople, Dr. C. premises a few particulars concerning the plague in general, as he finds them scattered here and there in Dr. Mackenzie's former letters to him on that subject. In a letter dated March 24, 1749, Dr. M. observes that, in his time the plague, whether at Constantinople, Smyrna, or any other part of the Levant, had been mostly sporadic, seldom epidemical. That therefore the articles in our news- papers, which so often mention the plague raging violently, are almost always false. At Constantinople, and all over the east, people shun the plague, and the infected, as much as we do; and every body, physicians as well as others, who have been with the sick, or in places infected, are all obliged to perform 40 days quarantine. The Armenians and priests are the only people who attend them; and they only to give them necessaries at a distance, or to perform the last functions of the church : and this the priest is obliged to do by his religion. The European plagues are much more violent than the eastern : those being really the Thucydidian, which sweep all away ; while these are only gentle corrections to put us in mind of mortality. The Doctor, in another letter, finds fault with the method used in England to prevent infection by shipping; " for, to what purpose (says he) keep ships in Sandgate creek for weeks, and even months, without landing and serening the goods? I hope you will allow, there is little to be feared from the bodies of men, who get in gooti health from Smyrna to England, which voyage is seldom per-, formed in less than 7 or 8 weeks ; which I presume will be thought too long for infection to remain in the blood without producing some effect. Therefore as all the danger is from the goods or cargo, greater care ought to be taken of this and less of the men. Your nation differs much from Italy or Marseilles, where a ship may, and often does, arrive in 8 days; for which reason, though it be necessary to look after the men, as well as the goods, still however they make a great distinction. You make none." It is observable, that from the beginning to the status or acme of the disease, they almost all die, afterwards its violence begins to abate, and about the end of the season most people recover. The symptoms of the distemper are chiefly, irregular fits of heat and cold; shiverings; violent head-ach, and retchings, for the first 3 or 4 days; great anxiety about the praecordia, &c. both before and after the eiiiptions, a wild staring countenance; sweats for the most part about the head and breast only, at the same time the extremities cold; a dry parched yellow furred tongue. The more violent those symptoms are, the greater the 240 PHILOSOPHICAL TRANSACTIONS. [anNO 1751. danger. Some are delirious, and raving ; others to a great degree stupid and dull; both these are fatal appearances. Some die in 5 or 6 days; some outlive 20 days, and then die: some walk the streets for many days, and afterwards die. Bleeding at the nose is reckoned a salutary sign. A swelling in the throat is a common symptom: for which if you bleed, it proves almost always fatal: for it is so far from abating this symptom, that after it a greater difficulty of breathing ensues, and the patient seldom survives it above 3 or 4 hours. The medical writers are divided as to the expediency of bleeding in the plague, some contending for it warmly, others as warmly condemning it. The Doctor distinguishes between the different stages of the distemper, and says, that as in the beginning, during the ebullition, bleeding may be of some service, so when the disease is advanced, and especially after the eruptions, it will prove fatal, as well as purging, or any other violent evacuation. A moderate diaphoresis ought always to be kept up. To the buboes, parotides, &c. they commonly apply a roasted fig with some white sugar powdered : and this they reckon the best sup- purative. They do not open the tumours, but leave them to break of them- selves. They give the sick cold water to drink, and order the cool regimen quite through the distemper. Abstract of Dr. Mackenzie's first Letter concerning the late Plague at Constan- tinople. Dated Constantinople, July 13, 1751. " We have at present the most violent plague, that has been at Constantinople in my time, by all reports. They are all taken the same way, with a shivering and vomiting, a violent head-ach, thirst and fever, of which they die the 3d or 4th day, rather in a stupor than a delirium ; and such as have the misfortune to te near the infected person, are taken in 7 or 8 days, though there are already many instances to the contrary. The Greeks and Armenians suffer most, next to them the Jews. The Turks suffer less in proportion than other nations." Dr. Mackenzie to Dr. Clephane, F. R. S. Dated Constantinople, Nov. 23, 1751. " During the 20 long years I have lived in this country, here and at Smyrna, there has scarcely been a year, excepting 3, in which the plague did not threaten, more or less; and in all that interval I observed no other difference in the seasons, than that the winters might begin more early, and continue somewhat longer, and with greater rigour ; though, by my thermometers, this difference never exceeded 5 or 6 degrees; which is no great difference here, where the south and north winds make a difference of from 15 to 20 degrees in 24 hours : so that I cannot see any other apparent cause of the virulency of the disease this year, besides the occasion of greater communication. In the months of February. March, April, and May last, the distemper was so strong at Cairo, as appears by letters from the English consul there, that no doors were opened for 3 months. In the VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 241 mean time there arrived here in May last 4 ships laden with Cairo goods, which goods and men being landed, they spread the infection over all the city at once, after which, one conveyed it to another by contact. The only apparent cause of the virulency in this case, is 4 ships arriving from Cairo, instead of 1 of 2, at the same time; and if you please, you may add to this some little difference of the seasons, mentioned in my letter to Dr. Mead, and a greater quantity of cucumbers, melons, and fruit, than usual, on which the poorer sort of people feed. However I do not believe the number of the dead anywise equal to common report, for the reasons following: The Turks have no bills of mortality; but they reckon, that in and about Constantinople there are consumed daily 20,000 killows of flour. Every killow is reckoned to weigh 20 oques, and every oque is equal to 400 drachms, and ] 6o drachms thought sufficient for a person for 24 hours, or one complete day, taking men, women, and children together. Therefore one killow makes bread enough for 50 persons per day; but the consumption of bread in the months of July, August, and September, was 3000 killows short; from which it is concluded, that 3000 x 30 = 150,000 must have died of the plague, without making any allowance for the great number of people, that run away to Prusa, Nicomedia, Adrianople, the islands, and such as must have died of other diseases in 3 months in a populous city of a million of souls, by the calculation of 20,000 killows per day. Next I must observe to you, that there are two vulgar errors with regard to the plague established in this country. They say that a plague which begins early, ends soon; which is false; for, in the year 1735, the plague began at Smyrna the 15th of February pretty hot, so that all the houses in Frank-street were shut up in February, and it continued till the latter end of November. Another vulgar error is, that the heat kills the plague at Smyrna, and the cold at Constantinople; which is very true with regard to Constantinople, but very false with regard to Smyrna; for proof look back to the year 1735, when the vigour of the malady showed itself most in the months of June and July, though so very hot, that some people were said to die of the heat in going from the town to the villages near it, so that it is very certain the heat does not kill the plague at Smyrna, as is generally thought and said." Dr. Mackenzie to Dr. Mead, F.R.S. Dated Constantinople, Oct. 2Q, 1750. " This is the only summer since I have been in Turkey that I can say we have been without any plague. The air was very temperate, no heavy rains, but high winds at N. e. from which point ouretesian winds blow, commonly called milhem in the Turkish language. Fruits have not been so plenty, or of such a good quality as usual; few fevers of the intermittent kind, but not so regular as usual VOL. X. 1 1 '242 VHILOSOPHICAL TRANSACTIONS. [aNNO 1751. in their symptoms ; for they were seldom attended with any head-ach, the tongue not much charged, and the urine seldom made any sediment of the lateritious kind; and if they were not taken in time, a yellow jaundice came upon them the 6£h or 7th day: and in the beginning of the fever, the patient seldom vomited bile as usual, but rather a pituitous matter." Dr. Mackenzie to Dr. Mead. Dated Constantinople, Nov. 13, 1751. " I remember to have written to you my sentiments of this distemper some years ago; and from all the observation I could make in the interval, I have no reason to change my opinion, viz. that it is brought from Cairo commonly ; and that when once a house or ship is infected, it is very difficult to eradicate the animalcula, semina, effluvia, miasmata, or whatever name is proper for the reliques or remains of it, which getting once into a nidus, lodge there: Condensed by the cold during the winter, and when rarefied by a certain degree of heat, they act on bodies which have a disposition, as women and children mostly, and so spread by contact only, without communicating any malignancy to the am- bient air. Otherwise very few could escape: whereas we found this last time, and on all such occasions, that whoever kept their doors shut, ran no risk, even if the plague were in the next house ; and the contact was easily traced in all the accidents which happened among the Franks. The patients were this year sick at stomach, and troubled with vomiting and nausea for 3 or 4 days after they were infected, and before the eruption of the buboes, carbuncles, or tokens; and in about 4 days more after the eruptions they died, or showed good symp- toms of recovery, such as, the fever, with all its symptoms, decreasing; the eruptions tending to maturation and suppuration, the nausea ceasing, and some appetite beginning." LXIV. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the Royal Society by the worshipful Company of Apothecaries for the Year 175], pursuant to the Direction of Sir Hans Sloane, Bart. By J. Wilmer, M. D. p. 396. This is the 30th presentation of this kind: completing to the number of 1 500 different plants. LXV. Of Dr. Bianchims Recueil d^ Experiences faites a Fenise sur la Medecine Electrique. By Mr. William Watson, F. R. S. p. 399. The account of this work indeed may be now thought less necessary, as, since the Abbe Nollet's journey to Italy, and our want of success here in our attempts to do the like, every body has considered what the Italians printed on the transmission of odours through the pores of glass, and on the subject of VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 243 medical electricity, as too hasty a publication. Mr. Winkler, however, from Leipsic, sent to the ScK:iety, long since these publications, some tubes and globes, whicli he said had transmitted odours by electrifying. What he con- jectured the glasses would do, fell infinitely short of what he first gave out; but even after the most careful trials, and complying with his instructions most scru- pulously, we were disappointed in our expectations. The gentlemen concerned in conducting these experiments, published by Dr. Bianchini, divided them into 3 classes. The first class contains a series of expe- riments made with tubes and globes containing odoriferous or other substances, in order to observe, when these were closely stopped, whether the odorous, as well as other effects of the substances included, would pervade the glass. The second class includes experiments made with tubes and globes, which have no- thing within them ; but the persons electrified hold in their hands, or sometimes place under their naked feet, odoriferous, purging, or even the most poisonous substances, in order to observe, whether the persons electrified in this manner would be sensible of the effects of these substances. The third class gives a series of experiments different from the two former,^ in which the substances before-mentioned are mixed with the water, as in making the experiment of Leyden. From these experiments we are to discover, whether from receiving the shocks from these bottles, the person is sensible of the effects in his body of the substances contained in them. But after many numerous and accurate trials of all these, on several persons, no such effects were felt by them. There ap- pears, through the whole course of the experiments contained in this work a great deal of care and accuracy. They were made by persons fully acquainted with the manner of employing their apparatus, and many of the experiments were several times repeated. After what has been done here at London, at Paris, and at Wirtemberg, with the like success, these experiments cannot, to unprejudiced persons, but be conclusive, that the extraordinary accounts from Italy and Leipsic, had no foun-- dation in fact ; and that no method has yet been discovered, by which from elec- tricity the powers of medicines could be made to insinuate themselves into the' human body. This conclusion, however, does not, nor is meant to operate, against the ad- vantages said to be gained by electricity itself. So subtil and so elastic a fluid admitted in a large quantity into our bodies, as, from undoubted experience, it greatly heats the flesh, and quickens the pulse, may, more especially when assisted by the expectation of success in the patient, in particular cases be attended with very great advantages. I I 2 244 ' PHILOSOPHICAL TRANSACTIONS. [anNO 1751. LXVI. The Case of the Operation of the Empyema, successfully performed by Mr. Joseph JVarner, F.R.S. and Surgeon to Guy^s Hospital, p. 407. Thomas Hines, aged IT, was admitted into the hospital, Dec. IQ, for a pain in his right side, and cough; which he had laboured under for 3 weeks. He was immediately put under the physicians care; but notwithstanding all proper methods used for his relief, his disorder increased till Jan. 13 following, when Mr. W. was consulted. On inquiry, he found him afflicted with the following symptoms, a quick, low pulse, frequent cough, and difficulty of breathing, which last symptom was greatly increased on lying on his left side, or on sitting upright. He appeared greatly emaciated, his countenance very pallid or sallow. The right side of the thorax was somewhat enlarged; the integuments were visibly thickened, but without the least discoloration, or perceivable fluctuation. However, being per- suaded from the foregoing symptoms, that there probably was an extravasated fluid underneath, he advised the operation, which was accordingly done on the spot, in the following manner: The patient being conveniently seated, he made an incision of about 3 inches long, with a knife, between the 10th and 11th rib, counting from above, and at about 4 inches distance from the vertebrae. The direction of the incision was agreeable to the course of the ribs, and on being made nearer to the superior edge of the 1 1th rib, than to the inferior edge of the 10th rib, the intercostal artery by that means escaped being wounded. On dividing the intercostal muscles, very near 20 oz. of matter were discharged, after which he introduced his finger through the wound into the cavity of the thorax, but found no adhe- sion of the lungs. Whence he conjectured that this- abscess was originally formed in the cellular membrane of the pleura, which had at length made its way into the cavity. What seemed to corroborate this conjecture, was that the violent symptoms, which happened on lying on the sound side, or on sitting up- right, did not occur till within a week before his application to him. From the moment the matter was discharged, he found immediate ease, his respiration became quiet ; his fever and cough gradually abated, till in about 6 weeks he became perfectly well in all respects, and was accordingly dismissed the hospital. The discharge from the wound continued in considerable quantities for the first fortnight ; during which time the wound was kept properly open with tents ; but when the discharge was no more than what might be expected fi-om any superfi- cial wound of the same size, all tents were disused, and superficial applications only made use of. TOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 245 LXVII. Of the Eruption of Mount Vesuvius in Oct. 1751, written at Naples, Jan. 15, 1752, N. S. p. 409. After the usual phenomena of smoke and flame, and bellowings, &c. there, on the 25th of October, in a place called Atrio del Cavallo, on the east side of the, mountain, a fiery fluid, like melted glass in a furnace, burst out, or rather seemed to boil over, which ran down the declivity of the mountain with great velocity and force, carrying along with it large stones, gravel, calcined earth, &c. In fi hours time it ran 4 miles, and covered vast tracts of fine land; destroyed many farm-houses, villas, and vineyards. The reason why it does so much mis- chief is, that it spreads itself, where the ground is plain, and covers in some places above an acre in breadth; but where there is a hollow ground, it forms a current river, making banks of its own substance, by cooling and hardening towards the edges; and when this current happened to be opposed by a rising ground, (the high banks of the cooling lava preventing its passage on either side) it formed high mountains of lava of 50 or 6o feet; till at last, by the weight and force of the red-hot river flowing incessantly from the bocca above, it burst out from under this new hill, and forming a second fiery river, pro- ceeded down the country, destroying all where it came. It was shocking to see trees, and vines loaded with fruit, floating on this river of fire. And, to our great astonishment, though we plainly saw the fluidity and rapid current of this matter, yet was it so impenetrable, that no weighty body would sink in it; nor did a sharp heavy iron instrument, thrown at it with great force, make the least impression on it, but, remaining on it a few minutes, it became red-hot like the lava. Nor could the pious procession and liquefaction of St. Januarius's blood on the spot put a stop to the destructive inundation; for it has run for these 2 months past, and runs a little still. LXFIII. Of an Hydrophoby. By The. mihraham, LL.D., F.R.S. p. 412. On March 29, 1752, Isaac Cranfield, a waterman, about 30 years of age, was received into the infirmary in Westminster, with an hydrophobia on him. He had been that morning with Mr. Heathfield, one of the surgeons to that infirmary, for advice; who being informed of that remarkable symptom, asked him, if he had not been lately bitten by. a dog? he answered, no. But his wife, who was with him, put him in mind, that he had received a wound from a dog about 9 months before. This he presently recollected : and said, it was a strange dog he met with at a public-house, that, as he was going to stroke him, gave him a little bite in the hand.. The same day, about one o'clock. Dr. Coxe, Dr. Watson, and Dr. W. met together to consult on his case. When he came to be examined, he repeated to them the manner of his being bitten, as Just mentioned ; and said further, that 246 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. he no sooner found himself hurt, but he gave the dog such a blow with a poker, as laid him dead on the spot. The wound, being slight, soon healed up, and he thought no more of it ; and he enjoyed good health till about 2 o'clock the Thursday morning before, when he was seized with a violent sickness and vomit- ing. The day following he continued very ill, and particularly felt an unusual pain, whenever he attempted to drink. Friday and Saturday that symptom grew worse ; and on Sunday he could not swallow the least quantity of liquor, with- out the utmost misery. This was the day they saw him. He looked somewhat wild in his eyes ; but in his discourse discovered no signs of madness. His pulse was extremely quick, but not weak and depressed. They examined his fauces, and found an inflammation. They desired him to give them an opportunity to see how he could bear an attempt to get down some liquid. He readily con- sented. He chose to sit down on the floor, then took a cup of water in his own hand, and put it to his mouth. The moment the liquor reached his throat, he suddenly sprung up on his feet, and ran about the room in the most violent agony that can be conceived. It must be observed, that he could get down small quantities of food that was solid, all the time this symptom was upon him. He informed them he had been let blood twice the day before he came to them. They agreed to take from him 12 oz. more, and to give him 1 gr. of extract. Theb. every hour, till there appeared some signs of stupor from the me- dicine. They also ordered him a clyster of decoct, furfuris with nitre. The blood was found next day not differing from that of a person in health. The extract was made up in pills of ] gr. each, which he could swallow without dif- ficulty. Dr. W. saw him again at 8 o'clock at night, at which time he had taken 5 grs. of opium, but did not appear to be in the least affected by it, being much in the same state he had left him in at one. He had had the clyster twice, but no stool either time. He went on with the pills till he had taken 15 grs. but no effect could be perceived from them. He passed the night in great anxiety, being for the most part on his legs, and at times light-headed. A good deal of frothy saliva was discharged from his mouth. About 8 o'clock in the morning he died. A few minutes before he expired, he said, that he was sen- sible he was going to die; and expressed much concern for the loss which his wife and children would have of him. That day they had him opened. The lungs were found full of blood. Water in the pericardium in the usual quan- tity. The blood in both ventricles of the heart fluid. The oesophagus without any morbid appearance. (Vide Boerhaave Aphor. 1140.) The aspera arteria full of such frothy substance as came from his mouth. The stomach filled with liquor, notwithstanding the small quantity he had drank since Wednesday evening. No other parts were examined. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 8,47 LXIX. Improvements made in the Air Pump. By Mr. S. Smeaton, p. 415. The chief causes of imperfection in the common pumps arise, first, from the difliculty in opening the valves at the bottom of the barrels ; lA\y, from the pis- ton's not fitting exactly, when put close down to the bottom ; which leaves a lodgment for air, that is not got out of the barrel, and proves of bad effect. In regard to the first of these causes; the valves of air-pumps are commonly made of a bit of thin bladder stretched over a hole generally much less than one tenth of an inch diameter ; and to prevent the air from repassing between the bladder and the plate, on which it is spread, the valve must always be kept moist with oil or water. It is well known that at each stroke of the pump, the air is more and more rarefied, in a certain progression, which would be such, that an equal proportion of the remainder would be taken away, were it not aftected by the impediments just mentioned: so that when the spring of the air in the re- ceiver becomes so weak, as not to be able to overcome the cohesion of the blad- der to the plate, occasioned by the fluid between them, the weight of the bladder, and the resistance that it makes by being stretched, the rarefaction cannot be carried further, though the pump should still continue to be worked. It is evident, that the larger the * hole is, over which the bladder is laid, a proportionably greater force is exerted on it by the included air, in order to lift it up ; but the aperture of the hole cannot be made very large, because the pres- sure of the incumbent air would either burst the valve, or so far force it down into the cavity, as to prevent its lying flat and close on the plate, which is abso- lutely necessary. To avoid these inconveniences as much as possible, instead of one hole, Mr. S. made use of 7? all of equal si^ie and shape ; one being in the centre, and the other six round it : so that the valve is supported at proper dis- tances, by a kind of grating, made by the solid parts between these holes : and to render the points of contact, between the bladder and grating, as few as possible, the holes are made hexagonal,' and the partitions filed almost to an edge. As the whole pressure of the atmosphere can never be exerted on this valve, in the construction made use of in this pump ; and as the bladder is fastened in four places instead of 2, the breadth of the hexagons are made -^ of an inch ; so that the surface of each of them is more than Q times greater than usual. But as the circumference of each hole is more than 3 times greater than common, and as the force that holds down the valve, arising from cohesion, is, in the first moment of the air's exerting its force, proportionable to the circum- ference of the hole ; the valve over any of these holes will be raised with 3 times more ease than common. But as the raising of the valve over the centre hole is * If we examine the force, that air rarefied 140 times can exert in a common valve through a hole of one tenth of an inch diameter, we shall find it not to exceed 0' grains at a medium. — Orig. 248 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. assisted on all sides by those placed round it ; and as they all together contribute as much to raise the bladder over the centre hole, as the air immedietely acting under it ; on this account the valve will be raised with double the ease, that we have before supposed, or with a 6th part of the force commonly necessary. It is not material to consider the force of the cohesion, after the first instant : for after the bladder begins to rise, it exposes a greater surface to the air underneath, which makes it move more easily. He has not brought into this account the force that keeps down the valve, that arises from the weight of the bladder, and the resistance from its being stretched ; for he conceives these as small in compa- rison of the other. But supposing all those difficulties to be absolutely overcome, the other defect mentioned in the common construction, would hinder the rarefaction from being carried on beyond a certain degree. For as the piston cannot be made to fit so close to the bottom of the barrel, as totally to exclude all the air ; as the piston rises, this air will expand itself; but still pressing on the valve, according to its density, hinders the air within the receiver fi-om coming out : hence, were this vacancy to equal the 150th part of the capacity of the whole barrel, no air could ever pass out of the receiver, when expanded 1 50 times, though the piston was constantly drawn to the top ; because the air in the receiver would be in aequilibrio with that in the barrel, when in its most expanded state. This I have endeavoured to overcome, by shutting up the top of the barrel with a plate, having in the middle a collar of leathers, through which the cylindrical rod works, that carries the piston. By this means, the external is prevented from pressing on the piston ; but that the air, that passes through the valve of the piston from below, may be discharged out of the barrel, there is also a valve ap- plied to the plate at the top, that opens upwards. The consequence of this con- struction is, that when the piston is put down to the bottom of the cylinder, the air in the lodgment under the piston will evacuate itself so much the more, as the valve of the piston opens more easily, when pressed by the rarefied air above it, than when pressed by the whole weight of the atmosphere. Hence, as the piston may be made to fit as nearly to the top of the cylinder, as it can to the bottom, the air may be rarefied as much above the piston, as it could before have been in the receiver. It follows therefore, that the air may now be rarefied in the receiver, in duplicate proportion of what it could be on the common prin- ciple ; every thing else being supposed perfect. Another advantage of this construction is, that though the pump is composed of a single barrel,* yet the pressure of the outward air being taken oft' by the • It is obvious that these improvements will equally obtain, whether the pump is conslnicled with a single or double barrel. — Orig. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. J4g upper plate, the piston is worked with more ease* than the common pumps with two barrels : and not only so, but when a considerable degree of rarefaction is desired, it will do it quicker ; for the terms of the series expressing the quan- tity of air taken away at each stroke do not diminish so fast, as the series an- swering to the common one. Having found the gages that have been hitherto made use of, for measuring the expansion of the air, very unfit to determine in an experiment of so much nicety ; Mr. S. therefore contrived one of a different sort, which measures the expansion with certainty, to much less than the 1000th part of the whole. It consists of bulb of glass something in the shape of a pear, and sufficient to hold about a half a pound of quicksilver. It is open at one end, and at the other is a tube hermetically closed at top. By the help of a nice pair of scales, he found what proportion of weight a column of mercury, of a certain length, contained in the tube, bore to that which filled the whole vessel. By these means he was enabled to mark divisions on the tube, answering to a 1000th part of the whole capacity, which being of about one tenth of an inch each, may by estimation be easily subdivided into smaller parts. This gage, during the exhausting of the receiver is suspended in it by a slip-wire. When the pump is worked as much as shall be thought necessary, the gage is pushed down, till the open end is im- merged in a cistern of quicksilver placed underneath : the air being then let in, the quicksilver will be driven into the gage, -f- till the air remaining in it be- comes of the same density with the external ; and as the air always takes the highest place, the tube being uppermost, the expansion will be determined by the number of divisions occupied by the air at the top. The degree, to which he has been able to rarefy the air in experiment, has generally been about 1000 times, when the pump is put clean together: but the moisture that adheres to the inside of the barrel, as well as other internal parts, on letting in the air, as in the succeeding trials worked together with the oil, which soon renders it so clammy, as to obstruct the action of the pump on a fluid so subtile as the air is, when so much expanded ; but in this case it seldom fails to act on the air in the receiver, till it is expanded 500 times : and this he found it to do, after being frequently used for several months without cleaning. He also generally found it to perform best the first trial at each time of using ; • Because, though the pressure of a column of air, equal to the diameter of the piston-rod, still presses on it, yet as there is only the friction of one piston, and that not loaded with the weight of the atmosphere; the friction of the leather against the side of the barrel, and that of the rack and wheel, is much less: so that, notwithstanding the addition of friction in the collar of leathers, that of the whole will be less. — Orig. + The bulb of the gage may be emptied of its quicksilver, without taking that out of the tube ; and the tube being held horizontal, the column of mercury in it will have no power to contract or expand the air at the top — Orig. VOL. X. K K 250 PHILOSOPHICAL TRANSACTIONS. [anNO 1751. though nothing had been done at it from the time preceding ; which after a great many trials made with this view, he also attributes to the moisture of the air mixing with the oil. Mr. S. also endeavoured to render the pneumatic apparatus more simple and commodious, by making this air-pump act as a condensing engine at pleasure, by singly turning a cock. This not only enables us to try any experiments under different circumstances of pressure, without changing the apparatus, but renders the pump a universal engine, for showing any effect that arises from an alteration in the density or spring of the air. Thus, with a little addition of apparatus, it shows the experiments of the air-fountain, wind-gun, &c. This is done in the following manner : the air above the piston being forcibly driven out of the barrel at each stroke, and having no where to escape, but by the valve at the top ; if this valve be connected with the receiver, by means of a pipe, and at the same time the ^alve at the bottom, instead of communicating with the receiver, be made to communicate with the external air, the pump will then perform as a condenser. The mechanism is thus ordered. There is a cock with 3 pipes placed round it, at equal distances. The key is so pierced, that any 2 may be made to com- municate, while the other is left open to the external air. One of these pipes goes to the valve at the bottom of the barrel ; another goes to the valve at the top, and a third goes to the receiver. Thus, when the pipe from the receiver, and that from the bottom of the barrel, are united, the pump exhausts : but turn the cock round, till the pipe from the receiver, and that from the top of the barrel, communicate, and it then condenses. The third pipe in one case dis- charges the air, taken from the receiver into the barrel ; and in the other lets it into the barrel, that it may be forced into the receiver. LXX. Of /Jphyllon and Dentaria Hepiaphyllos of Clmius, omitted by Mr. Ray. By Mr. fVilliam Watson, F. K. S. p. 428. Mr. Watson presented to the Society some specimens of 2 plants, then in flower, which he said were not frequently found in England. One of them was the anblatum of Cordus, or aphyllon of John Bauhin. This plant is deno- minated squamaria by Rivinus, and dentaria crocodylia by Tabernaemontanus. Linneus, in the Flora Suecica, calls it lathraea caule simplicissimo, corollis nu- tantibus, labio inferiore trifido. Mr. Ray, in his Synopsis Plantarum Anglias, takes notice of its being found near Dorking in Surrey, but the plant now pre- sented was collected near Harefield in Middlesex, The other plant offered was the dentaria heptaphyllos baccifera of Caspar Bauhin, or dentaria tertia baccifera of Clusius. This plant is treated of by Lin- neus, in the Hortus Cliffbrtianus, and by Van Royen, in the Florae LeydensiS VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 251. Prodromus, under the appellation of dentaria foliis inferioribus palmatis, summis simplicibus. This plant, which is frequently met with on the continent of the northern parts of Europe, has been but lately discovered to grow in England, and that only in one place ; viz. in a wood not far from Harefield in Middlesex, where it was first discovered by Mr. Blackstone, an ingenious apothecary in Fleet-street. This is one of those few plants omitted by the late Mr. Ray in his excellent Sy- nopsis, which are to be found natives here ; and, from their great scarcity, it is not wonderful that they were unobserved by that great naturalist. LXXl. Of a Machine for Killing Whales. By John Bond, M. D. p. 420. Whales being of the same structure internally with quadrupeds, must come frequently to the surface of the water to breathe ; and when they expel the rare- fied air from their capacious lungs, through a narrow tube, which protrudes above the upper jaw, they occasion a great noise, which the fishers term the blowing of the whales. This noise alarms the fishers, who are waiting for that signal ; on which they furnish a boat with necessa'-y instruments, and row quietly towards the whale. The harpooner, as they call him, sits rowing in the head of the boat, and observes certain silent signals, which the boat-steerer gives him, to inform him that he is near enough to strike the whale. Then the harpooner takes the harpoon in both hands, and darts it into the whale ; which, as soon as struck, plunges directly to the bottom, and moves with such prodigious velocity, that the rope which follows the harpoon often cuts deep grooves in the boat, and a man stands ready with an ax to cut the rope, if it does not run freely from the coil. The whale being hurt by the harpoon, stays longer than usual under water, till the blood, by the violent motion of the body, is collected about the heart, and consequently obstructed in the head ; the nervous influx is interrupted, the swimming bladder relaxed, and the whale becomes languid, and rises to the top to breathe fresh air where it rests for some time, to recruit its exhausted spirits ; which the fishers observing, row up and dispatch the whale with long lancets. It appears ft"om this account, that the greatest difficulty consists in making the rope fast to the whale, by means of the harpoon ; which is barbed in the common form of a dart, and is generally 20 oz. weight, and about 2 feet long, with a small stalk of flexible iron, and a socket at the end, about which the rope is spliced with a shaft of wood put into it, so that they cannot throw it any dis- tance with any degree of certainty ; therefore are never sure of darting a whale, till they are within a yard, or directly above her ; and there they are so much afraid of being dashed to pieces, that they often miss good opportunities, though they seldom meet with any so tame. They frequently see 40 whales within 30 kk2 252 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. yards of Uieir boats, but cannot strike one, unless it be sleeping, or suckling its young ones. Hence the bad success, and necessity of giving a premium to in- demnify the adventurers. Hence we also see that a machine, which would pro- ject a harpoon 30 yards with sufficient force and proper direction, must give a chance for taking 30 whales for one in the common way. Several machines have been proposed to answer this end, but have all proved abortive. The crossbow was tried, but was too weak, and subject to break with the frost in those cold climates. Gunpowder was next applied, it is said with no better success ; for, besides the difficulty of applying it to throw those heavy bodies in the form of darts, especially such as must carry a rope along with them, it frightens all the whales from the place, where it is fired, either by the light, or by the explosion, which it poduces ; perhaps both ways ; but probably more by the sound than the light ; for in the summer time there is in those parts a continual day for several months, so that a flash would not be remarkable. The machine which he recommends instead of those, is the ancient Balista, which is accurately described in the 13th chapter of Polybius, translated into French by Mons. Folard, who has nicely distinguished it from the catapulta, with which most of the ancient historians have confounded it, though these ma- chines had distinct offices ; for the catapulta threw vast masses of metal and stone in a parabolic curve, and the balista projected darts, some of 6o lb. weight, in a horizontal direction. The projectile power of both these machines de- pended on twisted ropes, which moved a lever placed in their centre. In the catapulta this lever moved vertically, and threw off globular bodies, as above- mentioned ; but in the balista there were 2 levers, which moved horizontally, and acted like a cross-bow. The force of this machine may be increased to any necessary degree, by multiplying the number of springs or ropes, and increasing the length of the lever, which turns the windlace, that draws back the cross cord, or in other words charges it. It has all necessary motions, and is contrived to stand on a pedestal in the head of a boat. It is so simple, that any person may learn how to use it in a short time; and when once it is successfully applied, we shall be no longer obliged to the instruction of the Dutch, who reckon it their interest to obstruct our success in every useful branch of trade. LXXII. An Engine for raising Water by Fire ; being an hnprovement of Sa- verys Construction, to render it capable of working itself, invented by Mr. De Moura of Portugal, F. R. S. described by Mr. J. Smeaton. p. 43(j. This engine consists of a receiver, a steam and an injection-cock ; a suction and a forcing-pipe, each furnished with a valve ; with a boiler, which, on ac- count of its bulk and weight, is not sent with the rest ; but, as it may be of the common globular shape, and having nothing particular in its construction, a de- TOL. XLVII.] PHILOSOPHICAL TBANSACTIONS. ^33 scription of it will not be necessary, as also the rest of these parts already men- tioned being essential to every machine of this kind, a further account of them may be dispensed with. What is peculiar to this engine, is a float within the receiver, composed of a light ball of copper, which is not loose in it, but fas- tened to the end of an arm, made to rise and fall by the float, while the other end of the arm is fastened to an axis ; and consequently, as the float moves up and down, the axis is turned round one way or the other. This axis is made co- nical, and passes through a conical socket , which last is soldered to the side of the receiver. On one of the ends of the axis, which projects beyond the socket, is fitted a second arm, which is also moved backward and forward by the axis, as the float rises or falls. By these means, the rising or falling of the surface of the water within the receiver, communicates a correspondent motion to the outside, in order to give proper motions to the rest of the geer, which regulates the open- ing and shutting of the steam and injection-cocks ; and serves the same purpose as the plug-frame, &c. in Newcomen's engine. The particular construction and relation of those pieces will better appear by the figure and references, than can be done by a general description. AB fig. 11, pi. 6, is an arm, which is fastened to a b, a conical axis, which goes through a conical socket in c, a triangular piece soldered to the receiver. This piece has this shape, to give liberty to the arm to rise and fall, that carries the float on the inside, d e is a small cistern, soldered to the receiver ; which, being kept full of water, keeps the axis and socket air-tight. This cistern is constantly kept full of water, by means of a small leakage through the wooden pegc, which follows the packthread cd to the cistern, e is a small weight to counterpoise the float within, f is a slider ; which being set nearer to, or farther from, the axis, will rise or fall a greater or less space, as may be required ; and is fastened by the screw g. This slider is furnished with a turn-about, h i, which is also fastened by a screw and nut at the end i, and sei-ves to adjust the length of F G G H, a chain, which gives motion, by means of the shorter chain k 1, to I K L, the balance, which opens and shuts the cocks ; and moves on the small axis L. G G are two pulleys, supported by two arms, that are fastened to the side of the receiver, and give the chain a proper direction in order to move the balance, mn is the steam-cock; the end n being supposed to be detached from a pipe, that gives it communication with the boiler, o is the injection-cock, whose key is turned by the arm o m. p a is the injection-pipe, communicating between the forcing-pipe above the valve, and the top of the receiver, r s is the arm, by which the key of the steam-cock is worked, i k two rollers annexed to the balance, which, by striking on the arm r s, open and shut the steam-cock, as the balance is moved backward and forward, r n o is the steam-cock's key- tail, which is furnished with two small rollers, n, o, which open and shut the 254 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. injection-cock, by acting on the arm o m in such a manner, that when the steam cock, is opened, the injection is shut, and vice versa, x is a bell of advice which, moving along with the balance, continues to ring as long as the engine is at work, v is a cock, which serves to discharge the air from the receiver, and is opened by hand when necessary, w is a weight sufficient to raise the balance to a perpendicular position, when it is inclined to the right, and also to overcome the friction of the float, axis, pulleys, chain, &c. To put the engine in motion, press down the arm a b, which will bring the balance over to the right side, and in its motion will open the steam-cock, and shut the injection ; set open the cock at v, that the air may be discharged by the entrance of the steam into the receiver. This done, shut that cock, and let go the arm ; the weight w will bring over the balance to the left, and in its mo- tion shut the steam-cock, and open the injection ; this presently condensing the steam into water, in a great measure leaves a vacuum in the receiver. Things remain in this situation, till the pressure of the atmosphere has caused the water to mount through the suction-pipe into the receiver, where, as its surface rises, it causes the float to ascend ; and, depressing the arm a b, raises the balance till it has passed the perpendicular ; and in its descent, which is done by its own gravity, the roller k lays hold of the arm r s, again opens the steam-cock, and shuts the injection. The receiver being now almost filled with water, the ba- lance cannot return, till the surface of the water in it subsides, and suffers the float to descend. This is performed by the elasticity of the steam ; which, at the same time that it fills the receiver, drives out the water through the forcing-pipe; and when the surface is descended so low, as to suffer the weight w to bring the balance beyond the perpendicular towards the lefl, it then falls of its own accord, and in falling the roller i lays hold of the arm r s, shuts the steam-cock, and opens the injection, as before. When the engine is to be stopped, observe when the balance lies to the right, to turn round the arm o m of the injection-cock, so that the tail of the steam- cock may miss it in the next motion ; so that at the same time that the receiver is filled with steam, and the steam-cock shut, the injection not being opened, the motion will stop for want of it. LXXIIL Concerning the Shells of Crabs. By Dr. Parsons, F. R. S. p. 439. Dr. P. had no doubt of the animal's casting his shell at certain seasons ; he only wanted to be satisfied, that the old exuviae were those of the soft crab ; which the mutilated claw assured of, however difficult it might be to conceive the manner of the animal's quitting it. The manner of his acquiring a new limb is in nowise different from that of his obtaining a succeeding new shell ; which is from a latent organization of the part ready for being indurated in due time. TOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 255 after the discharge of the old one ; when and not before, the testaceous matter has room for its secretion through its proper emunctories. It is in every circum- stance analogous to all the other animals which annually cast their integuments ; and, in its soft state, resembles that of a hen's egg before the testaceous matter is secreted by the glands of the membrane ; being soft and flexible : for this matter of all crustaceous animals, as well as of the eggs of fowls, is always suc- cessive to the entire formation of the membrane under it ; nor are the glands ca- pable of admitting the minima of the testaceous matter, till they have grown into a state proper for that purpose. Hence it may be concluded that the crab, the lobster, or other such animals, which had this property, are at first furnished with this membrane entire, and sufficient to be a defence against the violence of the agitated waves, and the rolling of sand, gravel, or other bodies, that might prove hurtful even before it can grow hard. This seems to be the method or- dained by the Creator for the preservation of every animal, however differing in other little circumstances. The snake, adder, lizard, or any other kinds, which we see endowed with this property, have the new skin entire under the shrivelled, falling, old one ; and it is, no doubt, the case with crabs, lobsters, and other crustaceous animals. In order to throw a little more light on this matter, it may not be disagreeable to observe the manner of the induration of the surfaces of the shells of eggs. It has been supposed that these consist of a nmcus indurated on the surface of the membrane : but this is not the case. The particles of the shelly matter are solid, though never so minute, and are carried with the fluids of the animal to the membrane, now ready to receive them into the ducts of its glands ; and are thence thrown into such order in the cellules of the external surface, as to ac- quire a structure no less firm in proportion, than bricks laid on one another ; and as capable of bearing any fair pressure, as a well built arch. When they are thus hardened and complete, they may be rendered as soft and flexible, by being macerated in vinegar, as if the shelly particles had never been placed on them. And this is not because the matter is quite dissolved; for a vegetable acid is not capable of making a total dissolution of it ; but the minute angles are destroyed, and the particles (which were before fixed like wedges to each other, to which they were inevitably guided in the secretion by the very structure of the receiving cellules of the membrane) are become round, by the destruction of their angles, and admit of being rolled in some measure on one another, so as in the whole to yield to the natural flexibility of the membrane. LXXjy. spherical Trigonometry reduced to Plane. By Francis Blake, Esq., F.R. S. p. 441. It is observable, that the analogies of spherical trigonometry, exclusive of the 256 PHILOSOPHICAL TRAKSACTION9. [aNNO 75 J. terms cosine and cotangent, are applicable to plane, by only changing th ex- pression, sine or tangent of side, into the single word side : • so that the lusi- ness of plane trigonometry, like a corollary to the other, is thence to be inlrred. And the reason of this is obvious ; for analogies raised not only from the onsi- deration of a triangular figure, but the cur\'ature also, are of consequence ;iore general ; and though the latter should be held evanescent by a diminution t the surface, yet what depends on the triangle will nevertheless remain. These tings may have been observed ; but on revising the subject, it further occurrd to Mr. B., and he takes it to be new, that from the axioms of only plane tripno- metry, and almost independent of solids, and the doctrine of the sphen- the spherical c-ases are likewise to Ix; solvctl. Suppose, first, that the 3 sides of a spherical triangle, abd, fig. 12, pi. (iare given, to find an angle a; which case will lay open the method, and lead t(the other cases, in a way that a|)pears the most natural. It is allowed that thean- gents, ae, af, of the sides, ad, ab, including an angle, a, make a plane agle equal to it ; and it is evident that the otiKr side, db, determines the angle inde by the secants ce, cf, at c the centre of the sphere ; whence the distance, ef, be- tween the tops of those secants, is given by case the fifth of obli(]ue plant; ri- angles, which, with the aforesaid tangents, reduces it to case the 6th of obliue plane triangles also-f-: and thus this 1 1th case of oblique triangles, so intricte hitherto, becomes perfectly easy. The 12th case is reducible to the 11th, nd the rest, whether right-angled, or oblique, we are authorised to considei ;is reducible to right-angled triangles, whose sides are not quadrants, but eitcr greater or less than such. Conceive therefore, now, in a right-angled sphenal triangle, gkh, fig. M, that the tangent, gm, and secant cm, of either leg, p., is already drawn ; and in the point, m, of their union, draw a perpendicular, il, to cm, the secant, directly above the other leg, viz. a perpendicular to the pine of the secant and tangent, that it may be perjiendicular to both (Eucl. 4, 1 ) ; for then will the tangent, gl, of the hypothenuse, gh, drawn from the saie point, which that of the leg was, constantly terminate in the perpendicular lie, that the radius and- tangent may make a right angle (Eucl. 18, 3.) Whei'-e these tangents, g m, gl, and the perpendicular line, m 1, together with thee- cants, c m, c I, will evidently form two right-angled plane triangles, g m 1. c ni ; and to one or other of these the spherical cases are easily transferred. Thu.«. in the spherical triangle, gkh, the hyjx)thenuse, g h, base, g k, and angle, at the base, be the parts given and required, when any two are given, the tlic may be determined by means of a plane triangle ; and at a single operation. Vt * See M. de la Caille's remark at the end of the spherical trigonometry prefixed to liin ElemeiittL. XLVII.] PHILOSOPHICAL TRANSACTIONS. JSJ hve, for instance, in the right-angled plane triangle, g m 1, formed as above, ti: base g m, and hypothenusc g 1, to find, by lase the 5th of right-angled plane dangles, the angle included, which is the same as on the sphere. And then if •fc base gk, the angle g at the base, and the perpendicular k h, be the spherical pits given and required: or if the angles g and h, and the hypothenuse g h, be te parts given and required, we liave only that former proportion of the hypo- tenuse and base, and angle at the base, in the triangles p n d, d p g, fig. 13, btained by the complements, to transfer to the plane. But secondly, suppose ke spherical proportion is of the 3 sides, any 2 being given, the 3d may be also nrnd at a single ojx.«ration, in the 2d right-angled plane triangle c m 1, formed 8 above. We have, for instance, the hypothenuse and base, c 1, cm, viz. the ecant of the spherical hypothenuse and base g h, g k, to find, by the 5th of jght-angled plane triangles, the angle, c, at the centre, which is the measure 4" k h, the side that was sought. And then again, if the hypothenuse, one eg, and the opposite angle, be the spherical parts given and required ; or if the wo angles and a It^ be the parts given and required, we have only the former )roportion of the three sides in the triangles, p n d, d r o, obtained by the com- plements, to transfer to the plane. Whence, the 6 proportions of right-angled spherical triangles being comprehended in this method, it is fully demonstrated, tiiat all the cases of these triangles are so to be resolved. The same might be deduced without the method of complements, but neither 11 so short nor satisfactory a way, and it shall therefore be omitted, LXXV. Of a Manuscript Treatise presented to the Royal Society, intitled, A Treatise on Coral, and several other Productions furnished by the Sea, in order to illustrate its Natural History. By the Sieur de Peyssonnel, M. D. &fc. Extracted and translated from the French, by Mr. William Watson, F. R. S. p. 445. This curious treatise, containing upwards of 400 quarto pages in ms, was trans- mitted to the R. s. fr'om Guadaloupe, where the author resided as physician botanist. It is the result of the observations of above 30 years. It is divided into 2 parts ; the first relates to coral only, and is subdivided into 1 0 chapters ; to which is subjoined a catalogue of the remedies and compositions, as well chemical as ga- lenical, in which coral is an ingredient. The 2d part is subdivided into 8 rlis- sertations, each of which has for its object some production of the sea ; and the whole tends to evince, that as well coral, as the other marine bodies here speci- fied, are produced by animals, viz. different kinds of urtica marina et purpura. To these the author has added a complete index, referring to every thing taken notice of in the whole work. This work is the result of a great number of very curious obsei-vations VOL. X. L L 258 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. and inquiries, and has for its object a part of natural history not hitherto well known. The first chapter of the work contains the opinions of the ancients concerning coral, and the observations made on it since their time ; among which are the opinions of Peireskius, Boyle, Piso, Boccone, Venette, the Comte de Marsigli, and those of M. de Peyssonnel himself In the 2d is an examination, whether coral is a plant, or a congelation ; in which are included 1 extracts, one from M. Tournefort's Elements of Botany, and the other from the Memoirs of the Royal Acad, of Sciences. The 3d chapter exhibits new observations, from which are discovered the urticae marinae and purpurae, which form coral ; where likewise are explained the formation and mechanism of this marine production. In the 4th chapter we find new chemical observations on the distillation of coral, which tend to prove that coral is the production of insects.* In the 5th are exhibited the de- finition, etymology, colours, and different sizes of corals, and of the insects inhabiting them. The 6th shows the places where they fish for coral, and the manner of fishing for it. In the 7 th we have the manner of working upon, and of polishing coral, and the commerce with it. The 8th, Qth, and 10th chapters give the chemical preparations of coral, its virtues and uses in medicine, when variously prepared. The subjects of the 8 dissertations of the 2d part of this work, are the several species of vermicular tubes found in the sea, the madrepores, millepores, litho- phytes, corallines, sponges, the various shell-fish, which inhabit the sea without changing their place, and the formation and mechanism of these several substances. This then is the general scope of our author ; and though every part of his work deserves to be considered, Mr. W. on account of the space usually allowed to works of this nature, confined himself to such parts only, as seemed most to merit the attention of the r. s. It had b<'en long the received opinion, that coral was soft in the sea, and was hardened by the air on taking it out of the water ; and the learned Mr. Boyle was not willing to quit this opinion. But as experiments are the only way of assuring ourselves of the truth, Boccone, for this purpose, went to sea in one of the coral-fishers vessels, and by plunging his arm into the water had an oppor- tunity of examining the coral, as they were fishing it up, before it came into the air. He invariably found it hard, except at its extremities ; where, on pressing it between the nails of the fingers, it furnished a small quantity of a milky fluid, resembling in some degree the juice of spurge or sow-thistle. Boccone observes further, that he saw several furrows under the bark of the coral, which terminate at the extremities of the branches, about which one might clearly see several small holes of the form of a star, which he imagines are destined for the produc- * Improperly called insects, being the production of worms. VOL. XLVII.j PHILOSOPHICAL TRANSACTIONS. 259 tion of branches. Venette's account of coral in his treatise of stones is much the same as Boccone's. The Count de Marsigli, in a letter to the Ahhi Bignon, in the year 1706, takes notice that, in order to give the most exact account of the production of coral, he wanted to be assured, whether the milky juice before mentioned was found there both in winter and summer, which was a matter of dispute even among the coral-fishers. For this purpose he went in winter for a few days to sea with the coral-fishers, and made several important discoveries in the nature of coral. He sent the Abbe Bignon an account of some branches of coral, which he found covered with flowers, and which was a thing unknown even to the coral-fishers themselves. These flowers were about a line and a half in length, supported by a white calyx, from which proceeded 8 rays of the same colour. These were of the same length, and of the same distance one from the other, and formed a star-like appearance. These bodies, which the Count de Marsigli imagined were flowers, M. Peyssonnel afterwards discovered to be the insects in- habiting the coral. As to the fact, whether the coral furnished a milky juice in winter as well as in summer. Count de Marsigli observed, that in December he found the milky juice between the bark of coral and its substance, in the same manner as he did in the month of June preceding. M. de Peyssonnel was unwilling that the idea, which the ingenious discovery of the Count de Marsigli had given, in regard to the flowers of coral, should be lost; and therefore, being at Marseilles in the year 1723, he went to sea with the coral-fishers. Being well apprised of what Marsigli had observed, and the manner of his making these observations, as soon as the net, with which they bring up the coral, was near the level of the water, he plunged a glass vessel in it, into which he conveyed some branches of coral. Some hours after, he ob- served that there appeared a number of white points on every side of this bark. These points answered to the holes, which pierced the bark and formed a circumscribed figure with yellow and white rays, the centre of which appeared hollow, but afterwards expanded itself, and exhibited seve- ral rays resembling the flower of the olive-tree ; and these are the flowers of coral described by Marsigli. Having taken this coral out of the water the flowers entered into the bark, and disappeareil ; but being again put into the water, some hours after they were perceptible again. He thought them not so large as the Count de Marsigli mentions, scarcely exceeding in diameter a large pin's head. They were soft, and their petals disappeared when they were touched in the water, forming irregular figures. Having put some of these flowers on white paper, they lost their transparency, and became red as they dried. He observed, that these flowers grew from the branches in every direction, from broken ones, as well as from those which were whole ; but their number lessened L L 2 260 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. towards the root ; and after many observations he determines that what Marsigli took for flowers were truly insects [worms.] Coral is equally red in the sea as out of it; and this redness is more shining when just taken out of the water, than even when it is polished. The bark of coral, by being dried, becomes somewhat pale. The extremities of its branches are soft, to the length of 5 or 6 lines ; they are filled with a whitish juice tending to yellow. The coral-fishers said, that in the month of May this juice some- times appeared on the surface of the bark ; but this, notwithstanding great atten- tion, our author could not observe. The body of coral, though hard, seems to give way a little when pressed between the fingers ; and being broken at different distances, when just taken from the water, there always came from it a small quantity of milky juice through certain tubes, which appeared to be destined to- wards the bark. Having inquired of the fishers in what direction the coral grew in the sea, they acquainted him, where the depth of the sea permitted them to dive, that they had found it growing sometimes perpendicularly downwards, sometimes horizon- tally, and sometimes upwards. Having verified these observations during the 8 days he staid with the fishermen, he adds, that he had never found any pores perceptible in the substance of the coral ; that there issued forth less milk from the large branches, than from the smaller ones ; and that the first was harder and less compressible. The bark of coral covers the whole plant from the root to the extremities of the smallest branches. It will peel off"; but this is only when just taken out of the water. After it has been exposed for a short time to the air, you cannot detach it from the body of the coral, without rubbing it to powder. This bark appears pierced with little holes, which answer to small cavities on the substance of the coral. When you take off a piece of this bark, you observe an infinite quantity of little tubes, which connect the bark to the plant, and a great number of little glands adhering to these tubes ; but both one and the other do not dis- tinctly appear, except when they are full of juice. It is from these tubes and glands that the milky juice of coral issues forth. Besides these, you see in vari- ous places the bark push itself outwards, where the substance of the coral is hollowed, and formed into the little cells, taken notice of by Boccone and Mar- sigli. In these you see little yellowish bodies, of the length of half a line, which terminate at the holes in the bark ; and it is from these that the flowers appear. Our author has found branches of coral, which, having been broken, have fallen on other branches, have fastened themselves there, and have thus conti- nued to grow. He has found, when a piece of stone, or shells, or other hard bodies, have offered themselves between the ramifications of coral, that it has expanded itself over them, and inveloped them in its substance. He has seen VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 26l- pieces of coral growing upon detached pieces of rock, glass bottles, broken pots, and other substances, .from which the plant could receive no nourishment. It has been said by great authority, that coral grows from the rocks perpendicularly downwards ; but our author has seen some growing to a round flint, which must necessarily have vegetated upwards, like most other plants. M. de Peyssonncl proceeds to examine, whether coral is a plant, according to the general opinion, or a petritication or congelation, according to some ; and after exhibiting the various arguments delivered in support of these, he concludes, that coral, as well as all other stony sea-plants, and even sponges, are the work of difterent insects, particular to each species of these marine bodies, which la- bour uniformly according to their nature, and as the Supreme Being has ordered and determined. The coral-insect, [worm.] which is here called a little urtica, pur- pura, or polype, and which Marsigli took for its flower, expands itself in water, and contracts itself in air, or when you touch it in water with your hand, or pour acid liquors to it. This is usual to fishes or insects of the vermicular kind. When our author was upon the coasts of Barbary in 1 725, he had the pleasure of seeing the coral-insect move its claws or legs ; and having placed a vessel of. sea- water with coral therein near the fire, these little insects expanded them selves. He increased the fire, and made the water boil, and by these means kept them in their expanded state out of the coral, as happens in boiling shell- animals, whether of land or sea. Repeating his obser\'ations on other branches, he clearly saw that the little holes perceptible on the bark of the coral, were the openings through which these insects went forth. These holes correspond with those little cavities or cells, which are partly in the bark, and partly on the sub- stance of the coral ; and these cavities are the niches which the insects inhabit. In the tubes, which he had perceived, are contained the organs of the animal; the glandules are the extremities of its feet, and the whole contains the liquor or milk of coral, which is the blood and juices of the animal. When he pressed this little elevation with his nails, the intestines andwholebcxly of the insect came out mixed together, and resembled the thick juice furnished by the sebaceous glands of the skin. He saw that the animal, when it wanted to come forth from its niche, forced the sphincter at its entrance, and gave it an appearance like a star with white, yellow, or red rays. When the insect comes out of its hole without ex- panding itself, the feet and body of it form the white appearance, observed by Marsigli ; but being come forth, and expanded, it forms what that gentleman and our author took for the petals of the flowers of coral, the calyx of this sup- posed flower being the body of the animal protruded from its cell. The milk before mentioned is the blood and natural juice of the insect, and is more or less abundant in proportion to its health and vigour. When these insects are dead, they corrupt, and communicate to the water the smell of putrid fish. 'i'Q'2. PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. The substance of coral, by a chemical analysis, scarcely furnishes either oil, salt, or phlegm : live coral with its bark furnishes about a 40th part of its weight in these ; but the bark of coral alone, in which are contained these animals, affords a 6th part. These principles resemble those drawn from human scull, hartshorn, and other parts of animals. After the accounts here laid down, we are able to assign the reasons of all the particular facts we observe in coral. We see why a branch of it, broken off and detached from its stem, may flourish. It is because the coral insects, [worms.^ which are contained in its cells, not having been injured, continue their operations : and drawing no nourishment from the stem of the coral, are able to increase, de- tach and separate. How they live and are nourished, is proposed to be explained in treating of the urtica of the madrepora, in which these animals are vastly larger, and appear very distinctly. In each hole or star of the madrepora, on which our author lays the evident proof of his new system, the urtica, placed in the centre of each pore, causes it to increase in every direction by lifting itself farther and farther from the centre of the stone. And in coral, and in the lithophyton, the urtica, being niched in their crusts or barks, deposits a juice or liquor, which runs along the furrows perceived on the proper substance or body of coral, and, stopping by little and little, becomes fixed and hard, and is changed into stone ; and this liquor, being stopped by the bark, causes the coral to increase proportionably, and in every di- rection. In forming coral, and other marine productions of this class, the animals labour like those of the testaceous kind, each according to his species, and their productions vary according to their several forms, magnitudes, and colours. After what has been here laid down, none will surely consider these marine productions as mere plants ; they are truly zoophytes, formed by the labour of the animals, which inhabit them, and to which they are the stay and support. Swammerdam seems to have proceeded very far in these discoveries, as we may see by his 1 Qth letter to Boccone. He goes further, and says, that having with a microscope examined a piece of coral, he found that each particle of it was composed of 10 or 12 angular and crystalline spherules ; and having sawed across a piece of coral, and given it the highest polish, he found, with the microscope, and even without it, that coral from its centre is disposed in strata, which he conjectures are formed by the application of the above-mentioned spherules. M. de Reaumur having been made acquainted with whatM. de Peyssonnel had observed, sent him a letter in the year 1726; where he takes notice, that no one had hitherto considered coral as the work of insects. But it seemed to him dif- ficult to establish this doctrine in the generality of marine productions, as was our author s opinion. That in whatever mode you considered coral and lithophytes. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 2^8 it did not appear possible that they were the constructions of the insects inhabit- ing them. That the only system to be adopted on these matters, was what he mentioned to our author before ; viz. that the bark of these bodies only is a plant properly speaking ; and that this deposits a stony matter, which forms the stalk necessary to sustain it. That then, in his opinion, all the difficulties vanish with regard to the organization of coral. In the course of this work our author mentions, that besides the animals to which coral owes its formation, there are 3 kinds, which he describes at large, which pierce and corrode the coral while in the sea, without preventing its in- crease. Contrary to what has been generally received, and to what even Mar- sigli asserts, coral grows among the rocks, and in the caverns of the sea, open to every exposure. It had always been said, that it never grew in caverns open to the north ; they must always be exposed to the south, at least to the east or west ; but on the coast of Barbary, which lies open to the north, coral is not less frequently found than elsewhere. It is generally observed to grow better and more readily in shallow, than in deep water ; and though they generally fish for it at the depth of 10 or 12 fathom, they sometimes get it, though but sel- dom, at 120. M. de P. then gives the manner of coral-fishing, and describes 2 different machines made use of for this purpose : one for fishing up the coral where the bottom is smooth ; being the same which is described by Grassendi in his life of Peyreskius. The other, which is called in the Provenqal language the salabre, is constructed so as to be employed where the bottom of the sea is rocky and unequal. He takes notice of the great skill and address of the coral-fishers in the management of these machines, as well as their sagacity in finding, at con- siderable distances from the shore, the very places where some time before they have been successful. He observes that all the productions of the sea, of which he treats, have been considered by naturalists sometimes as stones, and some- times as plants. Their stony substance deceived some, their tree-like appearance others ; insomuch that most writers, who have seen these bodies in their cabi- nets, have only considered their figures. They have denominated pora that class of them which seemed pierced with holes. Of these they found some having their holes large ; and these they called madrepora. There is another confusion among writers concerning these bodies : all those which had a tree-like form, whether their surfaces were smooth, without holes, or whether they were rough and unequal with them, were all styled corals. Those of any other form than that just now mentioned, were called madrepora, lithophyton, or alcyonium. It therefore appears necessary to establish some essential characters, to be able to distinguish these different bodies one from another ; but before these marks of distinction are laid down, our author thinks proper to examine what these bodies 264 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. are, and how they are formeci. He proceeds to remark that divers productions are found in the sea of a stony nature. These bodies are always equal, and al- ways the same in their different species : they have the same arrangement of parts, the same essential figure ; and differ in nothing but their outward form, like different vegetables. They are all pierced with holes and pores, which are of the same size and figure, and are of the same disposition in each species ; so that it appears evident that they are all produced from the same matter. But how they are produced, and their mechanism, has been hitherto unknown. When treating of coral, our author has given several observations of other persons relating to it ; but he finds none relating to the madrepora, and the other sea productions. But the knowledge which he had acquired on the nature of coral, conducted him to the discovery, which he made, of the animals that form the madrepora. As this system is new, he thinks it necessary to give hi§ observations, as they enabled him to form it. He defines the madrepora* to be all those marine bodies which are of a stony substance, without either bark or crust, and which have but one apparent opening at each extremity, furnished with rays proceeding from the centre to the circumference. He then takes notice of the means by which he found the madrepora to be the habitation of animals. So early as the year 1719, when his curiosity carried him to the coral fishing on the coast of Pro vence ; and though intent only upon coral, and neglecting to examine any other marine production, he nevertheless observed that the extremities of the madre- pora were soft, and covered with a mucosity, which had a fishy smell. Thence he suspected that they contained some kind of animal ; but his curiosity stopped here. Afterwards, being on the coasts of Barbary, the fishermen brought him, in a barrel of sea-water, one of those madreporas which are called in Provence, fenouille de mer, or sea-fennel. It had been put into the barrel as soon as it was taken out of the sea ; and he observed, that the extremities of this madre- pora were soft and tender, furnished with a transparent mucosity, like that of snails ; these extremities were of a beautiful yellow colour, and were 5 or 6 lines in diameter. In this he saw an animal, resembling the cuttle-fish, polype, or sea-nettle. The body of this fish filled the centre ; its head was placed in the middle of it, and was surrounded by several feet or claws : these feet filled the intervals of the partitions observed in the madrepora, and were at j)]easure brought to its head, and were furnished with yellow paj)illae. Its head or centre was lifted up occasionally above the surface, and often contracted and dilated itself like the pupil of the eye. He had the pleasure of seeing it move distinctly all its claws, as well as its head or centre. We can easily conceive all these motions, from what we have lately seen in the fresh-water polype, discovered by M. Trem- bley : and it is to be observed that the great sea polype (which is found on our A'OL. XLVir.] PHILOSOPHICAL TRANSACTIONS. '2^5 own coasts, and usually called a prule) the animal of the madrepora, that of coral, and the fresh-water polype, scarcely differ except in magnitude ; so that from having seen one, an idea of the rest may easily be formed. And Mr. W. mentions this with the more freedom, as on a visit with M. Trembley in Sussex at the late Duke of Richmond's, he saw the same order and economy observed in the coralline, as is mentioned by M. de Peyssonnel of the coral and madrepora. This phenomenon M. Trembley had discovered some time before ; and having put some fresh collected coralline into a phial of sea-water, brought it to Good- wood ; where after it had been suffered to remain at rest a few hours, by the assistance of a microscope a great number of very small white polypes, exactly in form resembling the fresh water polype, but infinitely less, were seen to protrude themselves from the inequalities of the coralline, each of which served as an ha- bitation for a polype. When the water was still, these animals came forth, and moved their claws in search of their prey in various directions ; but on the least motion of the glass, they instantly disappeared ; as was the case of the coral in- sect described by our author. But to return. The flesh of the animal of the madrepora is so soft, that it divides on the gentlest touch. This soft texture prevented M. de P. from de- taching any one; and he observes that there are in those seas several large spe- cies of urtica, which become pappy on the least touch. He mentions one sort of above a foot in diameter, whose body is as large as a man's head, and which is of a poisonous nature. After the madrepora had been preserved 3 days, the contained animals covered its whole surface with a transparent jelly, which melted away, and fell to the bottom of the water as the animal died ; and both the water and madrepora then had a putrid fishy smell. After having destroyed and consumed all the animals, the extremities of the madrepora became white. Imperatus seems to have bordered upon this discovery, when he says, " that the extremities of the madrepora are soft, of a obscure purplish colour, contain- ing a membranous substance ; whence one might suspect, that it partakes of a sensitive and animal life." Our author made the experiment here laid down on every species of madre- pora, which he found during the 3 months he continued on the coasts of Bar- bary. He observed always the same appearance, allowing some little difference for the colour and size of the animals, the texture of their bodies, and that of the bodies themselves, on which they were produced. From what has been extracted, concerning the coral and madrepora, an idea may be formed of the millepora, lythophyton, corallines, and sponges ; each of which is, according to our author, the habitation of numerous animals, and formed by them. He has given, from his own observations, particular accounts of each of these productions, and divided them into genera and species witli great accuracy ; and VOL. X. Mm- 206 PHILOSOPHICAL TKANSACTIONS. [aNNO 1751. though in common they are the habitations of animals, each species vaiying in form and bulk, and composing its cell in various forms and manners, and of different consistences, constitutes their essential character. As oysters, scallops, muscles, cockles, snails, &c. have a power given them, by the Author of Nature, of forming and enlarging their separate dwellings ; to these bodies, the subjects of this treatise, the same power is given, but in large families. In the madre- pora, its animal occupies the extremity ; in the millepora, the substance ; in corallines and sponges, the void places ; in coral and lithophytes, the cortical parts. Each of these animals, according to their kind, furnish substances dif- fering as much in consistence as in form. That of coral is extremely hard, and compact ; the madrepora and millepora are of a stony, but more loose texture ; the coralline is still more soft ; the lithophyton, of a substance nearer horn than stone ; and the sponge is soft and elastic. We observe a great variety in the operations of nature : the crab, the cuttle- fish, and the sea-spider, are endowed with a testaceous covering ; the esculent sea polype, and others of that class, have no such defence. So most of the animals hitherto noticed in this treatise, have a secure retreat ; but there is a production denominated, by Imperatus, lorica-marina, which has no such con- venience. It is as it were a soft madrepora. It grows at the bottom of the sea, and is a series of circular tubes, of about half an inch long, and 2 or 3 lines in diameter. Each of these, at the end most remote from the centre, is furnished with a sphincter, from which are occasionally protruded the legs or claws of the animal, like those before mentioned. The tubes themselves are likewise at pleasure lengthened and shortened. They are fastened to the rocks by a com- mon broad surface, after the manner of coral and such like marine productions, and are of a coriaceous substance. Hither likewise may be referred the soft lithophyton, usually called the sea-mulberry, and described by our author, which, on observation, exhibits nearly the same phenomena as the preceding. As to our author's opinion concerning the propagation of these animals : he supposes that they spawn as oysters do ; and that their spawn is inveloped in a viscous substance, like that of testaceous and other fish ; and that by this visco- sity it is fastened indifferently to whatever solid body lies in its way, whether it be a rock, glass, broken pots, flint-stones, &c. This viscous matter, coming to stagnate, is changed, according to its nature, into a solid and forms a lamina or stratum, such as is observed at the base of these productions, and ser\-es as it were for their first principle. The egg, inveloped in this viscous substance, is hatched in its proper time, and furnishes the animal, which resembles the sea- polype and other soft fish. These animals have all the necessary organs, and among others a particular gut, which, in the cuttle-fish, is filled with a black liquoif the use of which, according to the vulgar opinion, is that of being poured VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 26/ out at pleasure, to prevent the animal being taken when pursued : but this liquor, according to our author, serves the animals, the subjects of this treatise, with a matter capable of becoming hard ; and furnishes the increase of the body or shell of the animal, which, like other shells, remains always of the same form, and is of a size projx)rtionable to the animal. In the madrepora it lifts itself up under the animal, which always lies upon it ; but in the millepora it increases from the centre as the animal grows larger ; and thus these marine productions grow in just proportions. These animals are nourished without changing their place, like American oysters, which fasten themselves to the roots of the mangles ; or like what has been heretofore called concha anatifera, which fastens itself to old planks. Na- ture has furnished these polypes with claws, which they occasionally protrude from their cells, and seize their prey, as it passes by them ; and thus they are nourished and increase, according to their particular mechanism and construction. There are some species of the polype of the madrepora, which are produced singly, others in clusters. The first of these kinds may arise from the parent animal furnishing only one egg at a time: other species deposit a number of these eggs at the same time ; which, coming to life altogether, are joined in such a manner, that they seem to constitute one and the same body. The millepores grow one upon another ; their little animals produce their spawn, which attaching itself either to the extremity of the body already formed, or underneath it, gives a different form to this production. Hence the various shapes of the millepora, which is composed of an infinite number of the celjs of these little insects, which altogether exhibit different figures, though every par- ticular cellule has its essential form, and the same dimensions, according to its own species. On the whole, we see, that M. de Peyssonnel, if his system is admitted, has made a great alteration in this part of natural history. Naturalists had been divided, whether coral, and the harder productions of the sea, should be consi- dered as plants or stones. Those who considered them as stones, among whom was Dr. Woodward, imagined themselves justified in this opinion from their excessive hardness, and from their specific gravity ; and they were confirmed in this by observing, that if these bodies were calcined, they were converted into lime. Guisonagus, in his letter to Boccone, says positively that coral is not a plant, but a real mineral, composed of much salt and a small quantity of earth : he supposes its form given it by a precipitation, something like that of the arbor Dianae of the chemists. Dioscorides, Pliny, Caesalpinus, Boccone, Ray, Tournefort, and Geof^roy, thought coral to be a plant, from its root being fixed to rocks or stones, as those of trees are to the earth ; and from its sending forth a trunk, which ramified into M M 2 '2.68 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. branches. This opinion was seemingly strengthened by Boccone's observation of the milky juice at the tops and in the cells of coral, and most of all by the Count de Marsigli's discovering, in the year 1706, what he conjectured were the flowers of coral. Both these opinions, countenanced by long time, and great authority, M. de Pcyssonnel has endeavoured to overturn; and to show that these produc- tions were neither stones nor vegetables, but animals ; and that, like oysters, and other shell-fish, nature has empowered them to form themselves a stony dwelling for their protection and support, each according to its kind. Some account of M. de Peyssonnel's discoveries was transmitted by him to the Royal Academy of Sciences at Paris in the year 1727 ; but they were not much attended to, till Mr. Trembley's discovery of the fresh-water polype. This added much to their weight, and occasioned M. de Jussieu, in the year 1741, to visit the sea-coasts of Normandy, in order to satisfy himself of the nature of these marine productions, and his observations confirmed those of M. de Peyssonnel. The sentiments of that great naturalist M. de Reaumur, on this subject, may be seen at large in the preface to the 6th volume of his history of insects. LXXP^I. Concerning Inoculation, in a LeLler from Mr. Rich. Brooke, Sur- geon, to James Parsons, M. D. Secretary to the R. S, for Foreign Corre- spondence, p. 470. / In the year 1747, Mr. B. inoculated a young gentleman in Maryland, then about 20 years of age. He made a slight incision, about an inch in length, on the belly of the biceps muscle. In that he laid the lint impregnated with vari- olous matter, covered with a digestive pledget ; then bound them on with a roller. When he went afterwards to look at the arm, the roller being too slack, he found the pledget and lint were moved to the opposite side from the wound ; the inci- sion itself was but a little discoloured, but the part on which the lint lay, after its removal, was inflamed, and full of red pimples. He was afraid that the gentleman would not be affected with the disorder; but he had the fever, erup- tions, &c. at the usual times. As he had but about 30 pustules in all, he went through the different stages of the disorder without the least threatening symptom. This induced him to try to communicate the disorder without making any incision, only applying the infected lint to the arm, and confining it with an adhesive plaster. The few patients on whom he tried this method were children, and always with success. The absorbent vessels, he believed in young subjects especially, would always take in a sufficient quantity of the matter to contaminate the whole mass of the circulating fluids, and though the density of the pores, or scaly inspissations of the materia perspirabilis, in adults, might in some measure prevent the disorder from being communicated by contact ; yet friction would easily remove that obstacle ; for by this means we might make the cuticle as thin as we please, and the warmth VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 2^9 induced by friction would dilate the mouths of the absorbent vessels, and draw a moderate flux of juices to the part, so that they might take in a sufficient quantity of variolous matter to bring on the disorder,* LXXVIl. A Sequel of the Case of Horace JValpole, Esq. relating to the Stone, since his first Account in April, 1750.-|* p. 472. After having found himself for 1 years together perfectly well, and free from all symptoms of his former disorder, having taken for some time no more than one half of the quantity of soap and lime-water that he had before used; in November 1750, Mr. W. came out of the country in his coach in the usual travelling pace, without the least inconvenience. But having ventured some- times to go in a coach, after he came to town, on the stones, he began at times to feel the symptoms of the same disorder, which on any motion, besides that of going in a chair, even in walking to any degree, increased on him ; and driving only in his chariot through the two parks to Kensington, without going on the stones, he found himself greatly affected, by making frequently and involuntarily water, and sometimes bloody, accompanied with sudden stops, and severe pains. However, taking the precaution of going by water as far as the Old Swan, and being carried from thence in a chair as far as Whitechapel, he ventured in a chariot, fitted up with the best French springs, to go into the country with Mrs. Walpole about midsummer last; but before he had got half way to Epping, though the horses went but a gentle pace, he felt as great uneasiness, attended with the same severe symptoms, as he had ever done; which frequently returned, and continued during the whole journey for 4 days together, with little or no abatement, except while in bed ; whereas formerly, after he had lain some time, he was perfectly easy the whole night. In alighting from the coach, on his ar- rival at his house in the country, he had indeed a cruel fit; but after he had rested one night, and kept himself as quiet as possible for several days, he found himself perfectly well again; and as he never went in a coach, and did not walk much, during his whole stay in the country last year for about 5 months together, he never felt the least symptom of uneasiness. A few days before leaving the country in November last, he took a turn or two round his park in the chariot, free from pain; which encouraged him to undertake a journey to town again in the chariot, by short stages, and gentle driving: and it was performed in 5 days to Whitechapel, without his being sen- sible of the least inconvenience any part of the way ; neither had he felt any since • After the above account was communicated to the Royal Society by Mr. Brooke, the experiment was tried on 4 children by Dr. Conyers at the Foundling Hospitalj but was followed neither by the variolous fever nor eruption in any one of the instances.— Orig. ■\ See p. 135 of this vol. of these Abridgments. 270 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. his arrival in town; and he continued well, taking daily, as he had constantly done from the time he went last into the country, the full quantity of soap and lime-water, as formerly he took. LXXVIII. Part of a Letter from Mr. John Parker, an English Painter at Rome, to his Father at London, concerning the late Eruption of Mount F^esu- vius. Dated Rome, Dec. 20, 1751. p. 474. The eruption lasted about 25 days in all, and broke out of the side of the mountain, preceded by an earthquake, felt all over Naples at the time of the eruption. The mountain in the middle of the crater or cup, which formerly threw out the stones, sunk down, with about a third of the bottom of the said cup. The breadth of the matter it threw out is in some places half a mile over, in the least part near 6o feet; and it has filled a valley about 6o feet deep, and raised a mountain in the same place, of matter and ashes, about 50 feet high; and its whole length from the mouth to where it stopped, is about 5 miles; but it did not arrive at the sea by near 5 miles. The matter, or lava, seems to be composed of iron, antimony, sulphur, and salts, and is not always of the same colour, taste, &c. in every place. The thing I can compare it to most, is the large cinders thrown out of your great iron works, but covered over in many places with the above salts and sulphur. While the lava ran red-hot, a man threw a mass of the cool lava from a height upon it, which, far from sinking into it, rebounded like a ball. Its motion was as slow as the common walk of a man. It broke out in 5 different places. Mr. P. walked on it for about a mile while near 3 feet of the top were cooled; but for many feet underneath as red to the sight as the furnace of a glass-house. It covered and burnt up trees, houses, &c. in short all it found in its way. LXXIX. The Case of a Piece of Bone, with a Stone in the Bladder, success- fully extracted, by Mr. Joseph Warner, F.R.S. and Surgeon to Guy's Hos- pital, p. 475. Eliz. England, aged 48, in all other respects a healthy woman, had been afflicted with the symptoms of the stone in the bladder for about 2 years. After the usual preparation Mr. W. proceeded to the operation in the following un- usual manner: He cut the urethra obliquely upwards on the right side, to about half its length, by introducing a small knife into the groove of the staff, and found very little force requisite to the introduction of the necessary instruments into the bladder, and in the extraction of the stone, &c. On laying hold of the stone it broke; so that only a part of it, about the size of a pigeon's egg, was extracted on the first introduction of the forceps; but at the second time, he extracted a ragged piece of bone, weighing l6gr. Before it was cleansed, its VOL. XLVII.J PHILOSOPHICAL TRANSACTIONS. 271 cavities appeared filled and covered with a mixture of hairy and stony particles; whence he conjectures that it probably was the nucleus of the stone. Nothing remarkable occurred during the cure, but that the patient, ever after the second day from the operation, was capable of retaining her urine, and soon perfectly recovered. LXXX. Of a Water-Sjjout, raised off the Land, in Deeping- Fen, Lincoln- shire. By the Rev. Mr. Benj. Ray, of Cowbit near Spalding, p. 477. May the 5th, 1752, a phenomenon appeared about 7 in the evening, in Deep- ing-Fen, which, from its effects, seemed to be a water-spout, broken from the clouds. A watery substance, as it seemed, was seen moving on the surface of the earth and water, in Deeping-Fen. It passed along with such violence and rapidity, that it carried every thing before it: such as grass, straw, and stubble; and in going over the country bank, it raised the dust to a great height; and when it arrived in the wash, in the midst of the water, and just over against where Mr. R. lived, it stood still for some minutes. This watery substance spouted out water from its own surface, to a considerable height, and with a ter- rible noise. On its second route, it proceeded in a side line into the river, breaking in its passage a fishing-net, and there moved along, till it came to the church, where it again stood a little while, and then made its next passage through the space between the church and the parsonage house, towards Weston hills and Moulton chapel. In its way to these places, it tore up a field of turnips, broke a gate off the hinges, and another into pieces. Those who saw it evaporate, affirm it ascended into the clouds in a long spearing vapour, and at last ended in a fiery stream. There was a mist, like smoke, frequently round it. Three more were seen at the same time in different places. LXXXI. Of Two Methods, by tuhich the Irregularity of the Motion of a Clock, arising from the Influence of Heat and Cold on the Rod of the Pendulum, may be prevented. By John Ellicott, F.R.S. p. 470. The first of these methods consists in a particular construction of the pen- dulum itself, which occurred to him several years before. About the year 1732, an experiment, which Mr. Ellicott made to satisfy some gentlemen, that the rod of a pendulum was liable to be considerably influenced by moderate degrees of heats and cold, led him to consider, that as metals differ from each other in their density, it was highly probable they might also differ from each other in their expansion; and that this difference of the expansions of two metals might be so applied, as in a great measure to remove those irregularities in the motion of a clock, which arise from the effect of heat and cold on the length of a pen- 272 PHILOSOPHICAL TRANSACTIONS. [anNO 1751. dulum. With this view, not long afterwards he contrived the pendulum repre- sented by fig. 1, pi. 7- In which ab represents a bar of brass, made quite fast at the upper part by pins, and held contiguous, at several equal distances, by the screws 1, 2, 3, &c. to the rod of the pendulum, which is a bar of iron; and so far as the brass bar reaches is filed of the same size and shape, and consequently does not appear in the figure; but a little below the end of the brass bar, the iron is left broader, as at dd, for the conveniency of fixing the work to it, and is made of a sufficient length to pass quite through the ball of the pendulum to c. The holes 1, 2, &c. in the brass, through which the shanks of the screws pass into the iron rod of the pendulum, are filed as in the drawing, of a length sufficient to suffer the brass to contract and dilate freely by heat and cold under the heads of the screws; eeee represents the ball of the pendulum; f, f, two strong pieces of steel, or levers, whose inner centres, or pivots, turn in two holes drilled in the broad part of the pendulum rod, and their outer ones in a strong bridge, or cock, screwed on the same part of the rod, but omitted in the draft ; because, when put on, it covers this mechanism ; g, g, are two screws entering at the edge, and reaching into the cavity near the centre of the ball. The ends of these screws next the centre are turned into the form represented in the draw- ing, which, pressing with the weight of the ball against the longer arms of the levers, cause the shorter arms to press against the end of the brass bar at b. Things being in this situation, let us suppose that the rod of the pendulum, and the brass annexed to it, grow longer by heat; and that the brass lengthens more than the iron of the same length ; then the brass, by its excess of dilatation, will press the short ends of the levers downwards at b, and at the same time necessarily lift up the ball, which rests on the long ends of the same levers at f, f, to any proportion necessary; and provided the ends of the screws press on the levers at a proper distance from the centres, the ball will be always kept at the point of suspension, notwithstanding any alteration the rod of the pendulum may be liable to from heat or cold. What this distance ought to be, may very nearly be determined, if the difference of the expansion between the brass and iron bars be known; for the proportion the shorter arms of the levers ought to bear to the longer ones, will always be as the excess of the expansion of the brass is to the whole expansion of the iron, as may be thus easily demonstrated. Let the line ab, fig. 2, drawn perpendicular to the line ef, represent a bar of iron; the line cd a bar of brass; the pricked line bg the expansion of the iron, and dh the expansion of the brass bar, by the same degree of heat; let the line gi be drav/n parallel to the line ef, then will ih represent the difference of the expansion of the two metals; through the points h, g, draw a right line cutting the line ef, as in k; this line may be supposed to represent one of the levers turning on its centre at g, h the point where the brass bar acts on the shorter VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 273 end of the lever, and k the point where the screw acts on the longer end of the lever, which being the place where it intersects the line ef, it is evident the ball of the pendulum will be as much raised by the lever, as it would have been de- pressed by the expansion of the iron ; but the triangle ihg is similar to the triangle bgk ; and therefore as ih, the excess of the expansion of the brass, is to bg, the whole expansion of the iron, so will hg, the shorter arm of the lever, be to gk, the longer arm of the lever. Q. e. d. At Fig. 1 is placed a strong double spring, whose ends pressing against the under edge of the ball, hinder it from bending the brass bar by its forcible action at the point b, which, when the ball is of a considerable weight, it might other- wise be very liable to do. The description here given is exactly agreeable to the original contrivance; and the only alteration he afterwards made in it, consists in placing the screws g, g, within the ball of the pendulum, as represented in fig. 4. But as the success of this contrivance depended entirely on the supposition that metals were expanded differently by the same degree of heat, before putting it in execution, he inquired what experiments had already been made on this subject: when Mr. John Eames put into his hands Mr. Graham's account of his quicksilver pendulum, as it is now commonly called, published in the Philos. Trans. N° 3Q2, which account was introduced by the following paragraph : " Whereas several, who have been curious in measuring of time, have taken notice, that the vibrations of a pendulum are slower in summer than ip winter; and have very justly supposed this alteration has proceeded from a change of length in the pendulum itself, by the influences of heat and cold on it, in the different seasons of the year; with a view therefore of correcting in some degree this defect of the pendulum, I made several trials, about the year 1715, to dis- cover whether there was any considerable difference of expansion between brass, steel, iron, copper, silver, &c. when exposed to the same degrees of heat, as nearly as I could determine; conceiving it would not be very difficult, by making use of two sorts of metals diflfering considerably in their degrees of expansion and contraction, to remedy, in great measure, the irregularities, to which com- mon pendulums are subject. But though it is easily discoverable, that all these metals suffer a sensible alteration of their dimension by heat and cold ; yet I found their differences in quantity, from each other, were so small, as gave me no hopes of succeeding this way, and made me leave off" prosecuting this affair any farther at that time." The reading this paragraph proved at that time sufficient to make him lay aside all thoughts of succeeding in a contrivance founded on principles, which a gentleman of so great abilities, and known accuracy in making experiments, had after trial judged to be insufficient. And it was not till about the latter end of VOL. X. Nn 274 PHILOSOPHICAL TRANSACTIONS. [anNO 1751. the year 1734, that he again resumed them on the following occasion. A gen- tleman desirous to make some experiments concerning the expansion of metals, employed him to make an instrument like one invented by Mr. Muschenbroek for that purpose, which he calls a pyrometer. On looking over Mr. Muschen- broek's experiments, he not only found the difference between the expansion of some of the metals much greater than he expected, but, as he thought (if they were to be depended on) sufficient to answer his former purpose. This led him to consider the structure of the instrument which Mr. Muschenbroek made use of in his trials, and on examination he thought it liable to some objections, which would probably make the result of experiments with it very uncertain. He therefore endeavoured to contrive one of a different construction, that might be more to be depended on. Such an instrument he some time afterwards com- pleted : and though it was not in every respect so accurate as he could wish, he is fully persuaded that such experiments as are carefully made with it, may be depended on, as very near the truth. Having made a great variety of experi- ments with this instrument on bars of different metals, as nearly of the same dimensions as possible, he found, on a medium, their several expansions by the same degree of heat to be as follows: Gold Silver Brass Copper Iron Steel Lead 73 103 95 89 60 56 149. Thus finding so great a difference between the expansion of brass and iron, he immediately determined to make a pendulum after the manner above described, composed of those two metals, and also ordered a clock to be made, with the utmost aire and exactness, with which he intended to make the experiments. These were both finished in the beginning of the year 1738; and having no reason to doubt of success, he showed the pendulum to the late Mr. Machin, and gave him a drawing and description of it, in order to its being communicated to the Royal Society; but objections were made to it, of which the only one that appeared to have any weight was, that it had been found by experiment, that two bars of different metals, screwed together so as to be in contact with each other, would not expand regularly and smoothly, but by jerks. In order to exa- mine into the force of this objection, he directed two bars of equal dimensions to be made, one of brass, the other of iron, of about 2 feet in length, fastened together after the same manner as the two rods of the pendulum, which he intended to place so, that, by acting very near the centre of an index of a con- siderable length, even the smallest alteration in the bars would be made sensible, and by the motion of the index, he should be able to form a judgment, whether the rods moved regularly and freely, or not ; but before this was put into execu- tion, he contrived, by fastening the two bars to the back plate of a clock, not only to make them answer the end above proposed, but at the same time to VOL. XtVII.J PHILOSOPHICAL TRANSACTIONS. 275 lengthen or shorten a pendnlum of a common construction, in such a manner, as sufficiently to correct the irregularities arising from the influence of cold or heat upon it. The manner of applying them is represented in fig. 3, In which, aaaa represent the back plate of the clock, bbb a triangular piece of brass, screwed by two screws, through the slits cc, to the plate, yet so that it may be drawn backward or forward by means of the screw at d ; ef is a brass bar, about 2 feet in length, made fast at the bottom, by a screw and two pins at f, to an iron one of equal dimensions, to which it is likewise screwed by the screws l , 2, 3, &c. after the same manner as the rod of the pendulum already described. The iron bar is fastened at the upper end of the triangular piece of brass, nearly under that part of the brass bar marked e; gh is a strong brass or iron lever, moveable on a centre at g, and is supported by the upper end of the brass bar; ii is the cock, on which, in a common clock, the pendulum is hung; kk, part of the rod of the pendulum, whose spring passing through a fine slit in the cock ii, is fastened to a stud rivetted into the lever at 1. The slit in the cock must be made so close, as to prevent the spring from having any lateral motion in it. From this description it is evident, that if the brass bar expand more than the iron one, it will raise up the lever, and consequently the pendulum, which is fastened to it; and as the length of the pendulum is only from the centre of oscillation to the under part of the slit, through which the spring passes, the pendulum will be thereby shortened; and by making the point of the brass bar to act on a proper part of the lever (to which it is capable of being adjusted by means of the screw d) the pendulum may be shortened to whatever degree shall be necessary. To prevent the pendulum from bending the bars, which it would be liable to do, if the ball of the pendulum was of any considerable weight, the end of the lever, farthest from its centre of motion, is hooked to the end of a chain, which is wound about and fastened to a small pulley at m. On the same arbor, to which this pulley is fixed, is fastened another pulley, of a much larger diameter, to which is hung, by a silk line, the weight or counterpoise n. By means of this counterpoise, any part of the weight of the pendulum may be taken off from pressing against the brass bar. And if, on the end of the arbor to which the pulleys are fixed, an index be placed, so as to point to a graduated circle, the least motion of the lever will not only be easily perceived, but also whether that motion is uniform and regular, or not. And on having, some time after, made a clock with this contrivance added to it, he found the index not only to move very sensibly, but very regularly, and never, that he could perceive, by jerks. And he doubts not, but, when the [xiint of bearing of the brass bar on the lever NN 2 27<5 FHILOSOPHICAL TRANSACTIONS. [aNNO 1751. is once well adjusted, it will be found to lengthen or shorten the pendulum to as great a degree of exactness, as any other method whatever. The method he took for adjusting the longer arms of the levers of the pen- dulum to the shorter ones, is represented in fig. 4. To a strong post, fixed to the wall, is fastened a small shelf, supported by two brackets a, b. In the middle of this shelf is fastened a wire, by the screw e; to the end of which the pen- dulum is to be hung. Below this shelf, at the distance of about 40 inches, is placed the index cd, turning freely on a centre; the length of the index is 50 inches. At the distance of half an inch, on a part of the index produced be- yond the centre, is placed a steel pm; and in the back of the pendulum, as near the centre of oscillation as may be, is drilled a hole to receive this pin ; when the pendulum is hung on the wire against the post, and the wire is screwed higher or lower by the screw e, till the pin resting against the upper part of the hole (which is filed into a proper shape for that purpose) keeps the index nearly in a horizontal position. Below the bottom of the pendulum is placed a second index fg, exactly like the former, except that it is kept in a horizontal position by the screw k, bearing against the end of the iron rod. When the experiment is to be made, the pendulum is first put into a box, and gradually heated by a large fire, to a considerable degree, being often turned, that every part may be equally exposed to the fire. And having continued shut up in the box for some time after it is removed from the fire, that the two rods may be heated as uniformly to the same degree as possible, the pendulum is hung on the wire, and the two indexes made to stand nearly in a horizontal position. The two graduated plates h, i, are then slid on a wire, till the divisions in each marked o are pointed to by the indexes. As the pendulum cools, the lower index will be seen gradu- ally to descend; but if the ends of the two screws, in the ball of the pendulum, act on proper parts of the levers, the upper index will continue in the same place. If the ends of the screws be either too far ofi^, or too near the centres of the levers, the index will either rise or descend; and by comparing the number of divisions it has varied, with those which the lower index has varied, a near estimate may be made, how much the screws require to be altered; and, in a very few trials, they may easily be adjusted to a very great exactness. In order to make an actual trial how far this contrivance of the pendulum will answer the end proposed, it is necessary, that the clock, to which the pendulum is fitted, be made with great exactness, and entirely to be depended on; for otherwise the experiments will be verv uncertain, as he found in the clock he first made use of. In order to render this clock as perfect as possible, he made it in several respects difl^erent from the common ones, in hopes of removing some imperfec- tions he apprehended they were liable to. But as in this attempt he fell into an ▼OL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 377 error, which it was a considerable time before he discovered, his making the trial was thereby greatly retarded. And in order to prevent others from falling into the like mistake, he gives the following short account of it. In a common clock, the pendulum is usually hung by a spring to a cock on the back plate of the clock, while the wheel and pallets, by which the pendulum is kept in motion, are placed in the middle of the frame ; and the pendulum is moved by a piece of steel, called the crutch, riveted to one end of the arbor, to which the pallets are fastened. This disposition of the pieces he apprehended liable to some considerable objections : to remedy which, he contrived to fix the pallets to the upper part of the pendulum itself, above the centre of motion ; and, in order to make the pendulum vibrate as freely as possible, it was made to turn on two steel points, and was hung in the middle of the frame, exactly under the swing-wheel, and so as to vibrate in the same plane with it. By this means he was in hopes, that it would have moved with much greater freedom and regularity, than when hung after the common method ; and on trial it was found to move with so great freedom, that a pendulum of above 20 pounds weight, when hung in its place without the clockwork, and made to vibrate through an arch of 2 degrees, was found to make above 1200 vibrations, before it had lost half a degree, and was observed to have a sensible motion above 20 hours afterwards ; and the clock, when first put together, was kept going, for several days, by a weight of only 1 1 ounces, hung to the end of a single line. But it was not long before he discovered, that this great freedom made it liable to be considerably affected by the least motion. A remarkable instance of this he communicated to this Society, which was published in the Philos. Trans. N° 453. But the greatest objection to this method was, the points being subject to wear ; and he found that the least alteration in them would occasion the clock to vary much more than he could have imagined. To remedy this inconvenience, he made the pendulum to move upon edges, like those on which the beam of a pair of scales turns ; but he found these likewise liable to wear, though not in so short a time as the points ; so that, after much time spent in making several experiments, in order to remedy this inconvenience, he found himself obliged to lay this method wholly aside, and to hang the pendulum on a spring, as usual. This alteration being made, he found that the clock went very regular ; and, after a sufficient trial, he was fully satisfied the pendulum would answer his expec- tations. But, fearing lest he might be thought prejudiced in favour of his own invention, he engaged the Rev. Mr. Professor Bliss to make trial of it ; and ac- cordingly, in the beginning of the year 1750, he sent to him, at Oxford, a clock for that purpose ; and in January last he received from him a letter, giving his opinion of it, of which the following (so far as relates to the clock) is an exact copy. 278 PHILOSOPHICAL TKANSACTIONS. [aNNO 1751. " SIR, " I have now had thorough trial of the clock ; and am perfectly satisfied that your pendulum takes oft' the effect of heat and cold, as well as either the gridiron- pendulum (as it is commonly called) or the quicksilver pendulum ; and this upon •sufficient trial for near 2 years. It has this advantage of both the fore-mentioned ones, that it may, by lengthening or shortening the levers, be easily adjusted to the exact proportion of the difference of the iron and brass, which neither of those kinds is capable of, without very great trouble and difficulty. I was in- deed prejudiced against the method of doing it by levers, as I had heard the late Mr. Graham say, that he had tried levers in different ways, that he found they did not work regularly and freely, but by jerks. However, in your method I am satisfied, by the fullest experience, that they succeed as well as either of the other sorts, or perhaps any other kind that may be invented hereafter," Before concluding, he observes that, in the year 1 748, he made a model of a contrivance to be added to a pocket-watch, founded on the same principles, and intended to answer the like purpose, as the pendulum above described. And, at a meeting of a council of the Society, on Feb. 15th last, he produced a watch which he had made for a gentleman, with this contrivance added to it, and also the model, by which was shown what effect a small degree of heat would have upon it. LXXXTI. Of a Neiv Tackle or Combination of Pulleys. By Mr. John Smeaton, p. 404. The axis in peritrochio, and the compound pulley, are the only mechanic powers which can with convenience be applied for moving large weights, when the height to which they are intended to be raised is considerable. The ex- cellence of the former is, their working with little friction ; that of the latter, in their being easy to be moved from place to place, and applied extempore, as oc- casion requires. The present method of arranging pulleys in their blocks may be reduced to 2. The first consists in placing them one by the side of another on the same pin ; the other in placing them directly under one another, on separate pins. But in each of these methods an inconvenience arises, if more than 3 pulleys are framed in one block. For, according to the first method, as the last line, by wliich the draught is made (or, as it is commonly called, tlie fall of the tackle) must necessarily be on the outside pulley or shieve ; the difference of their friction will give it so great a tendency to pull the block away, that as much will be lost by the rubbing of the shieves against the block, on account of its obliquity, as will be got by increasing the number of lines. The 2d method is free from this objection ; but, as the length of the two VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 279 bhx^ks, taken together, must be equal to the sum of the diameters of the 6 pulleys, besides the spaces between for the ropes, and the necessary appendages of the framing, when more than 3 pulleys are in each block, they run out into ^ich an inconvenient length, as to deduct very considerably from the height to which the weight might otherwise have been raised : so that, on those accounts, no very great purchase can be made by the common tackles of pulleys alone. In order therefore to increase its power, sometimes a 2d tackle is fixed on the fall of the first ; but here it is obvious, that whatever be the power of the 2d tackle, the height to which the weight might otherwise have been raised by the first, will be less, in the same proportion, as the purchase is increased by the 2d. Again, very frequently the fall of the first tackle is applied to an axis in peri- trochio, which increases the purchase very commodiously without the inconve- niences last-mentioned ; but then the machine is rendered cumbersome, and con- sequently less fit for a moveable apparatus. All those impediments Mr. S. has avoided, by combining the two methods, above described, in one. The pulleys are here placed in each block in 2 tiers ; several being on the same pin as in the first method, and every one having another under it, as in the 2d; as also that, when the tackle is in use, the 2 tiers that are the most remote from each other, are so much larger in diameter than those that are nearest, as to allow the lines of the former to go over the lines of the latter without rubbing. From this construction arises a new method of reeving the line on the shieves : for here, whatever be the number of shieves, the fall of the tackle will always be on the middle shieve, or on that next the middle, according as the number of pulleys on each pin is odd or even. To do this, the line is fixed to some convenient part of the upper block, and brought round the middle shieve of the larger tier of the under block, from thence round one of the same sort next to the centre one of the upper block ; and so on till the line comes to the outside shieve, where the last line of the larger tier falls on the first shieve of the smaller, and being reeved round those, till it comes at the opposite side, the line from the last shieve of the smaller tier again rises to the first of the larger, whence it is conducted round till it ends on the middle shieve of the upper block on the larger tier ; as will appear more plain, by inspection of figure 5, pi. 7- In this method all the lines are clear of one another, and the blocks are kept parallel. The model which he showed the Society, and from which he made the draught, is a composition of 20 shieves, 5 on each pin. With this model, which may easily be carried in the pocket, he had raised 600 weight. But with a tackle of this sort, properly executed in large, one man will easily raise a ton. 280 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. and a greater number in proportion. He had tried several numbers of shieves as far as 36 ; but 20 seemed to be the largest number that will answer well in practice. A very commodious tackle of 1 2 might be executed in wood, in the same manner that common blocks are made. In constructing a tackle of 20 for 3 tons, the larger tier of shieves should not be less than 8 inches, the running line need not be thicker than half an inch diameter, and the iron pins need not be so thick- LXXXIII. On some Vegetable Balls. By IVm. Dixon, Esq. F. R. S. of Lover- sail near Doncaster in Yorkshire, with Remarks on them by Mr. IVilliam Watson, p. 498. These balls seem to be plants of a very particular kind. They were taken up in a fresh- water lake, on a large common in the East Riding of Yorkshire, about 12 miles west of Hull. The lake is from 100 to 200 acres in size, according to different seasons, and empties into the Humber ; which is pretty salt, and has sometimes infected it a little at very high tides. The water is very bright, and the bottom in many places is quite covered with these balls, like a pavement, at different depths. These now sent were about 6 inches under water ; and many are left quite dry every summer. On this communication Mr. Watson observes, that the vegetable here mentioned, he has never seen before ; neither had he been able to find it described in any of the botanic writers he consulted. The matter of which it is composed, is that of a conferva ; and should therefore have had a place under that genus in Dillenius's Historia Muscorum. They are of a deep green mossy colour, are hollow, of an irregularly spherical figure, and of different sizes, from an inch an half to 3 inches in diameter. They are co- vered with very short villi externally, and the thickness, from their external to their internal surface, is about a quarter of an inch ; their texture is most com- pact the nearest to the surface. He denominates them globose conferva. Mr. Ray, in his History of Plants, vol. 1. p. 83, describes a plant, which he found in Sicily, something like this now sent by Mr. Dixon. LXXXIV. Of the Copper-Springs in the County of IVichlow in Ireland. By the Rev. Henry Kenroy, D. D. p. 500. These mines lie in the southern part of the county of Wicklow, on each side of the river Arklow, and about 7 miles west from the town of that name, among hills that rise to the height of small mountains. The mine, which was formerly wrought, is that of Ballymurtogh, on the south bank of the river. It yielded vast profit to the undertakers; but it has been disused for some years past. This is amply compensated by the far richer mines of Crone-Bawn, on the north side of this river. VOL. XLVII.] PHILOSOPHICAL TRAWSACTIOWS. 281 Crone-Bawn is a hill of 2 miles in circumference, and about 1000 feet in height, in the form of a large inverted bowl. The bowels of this hill are full of rich mines. But the principal works lie on the east side, about halfway up the hill, where several shafts are sunk, fk>m 50 to 70 fathoms deep. The first mi- neral met with is an iron stone. Beneath this they arrive at a lead ore, which seems mixed with clay, yet yields a large quantity of lead, and some silver. Under this lies a rich rocky silver ore, which sparkles brightly, and yields 73 ounces of pure silver out of a ton of ore, besides a great quantity of fine lead. Having pierced some fathoms through this, they arrive at the copper ore ; which is very rich, and may be pursued to a vast depth. In order to carry off the water from the mines, there are levels carried on a great way under ground, from the lower part of the hill. Out of these levels issue large streams of water, most strongly impregnated with copper. An ac- cidental discovery, which happened not long ago, is likely to make these streams more beneficial than all the rest of the mines. Some of the workmen having left an iron shovel in the stream, found it some weeks after incrusted with cop- per, insomuch that they thought it converted into copper. This gave the hint of laying bars of iron in these streams, which is done in the following manner : Oblong pits are dug 1 0 feet long, 4 wide, and 8 deep : the bottom laid with smooth flags ; the sides built up with stone and lime, with wooden rude beams across the pits to lay the iron bars on. Chains of these pits are continued along the stream, as far as the directors please ; for the water never abates of its qua- lity, if it were conveyed from pit to pit through a thousand. Soon after the iron bars are laid in these pits, they contract a copper rust, which by degrees entirely eats away the iron. The copper, which is in the water, being thus continually attracted and fixed by the iron, subsides to the bottom of the pit. To hasten this dissolution, the iron bars are sometimes taken up, and the rust rubbed off them into the pit. In the space of 1 2 months the whole bar is commonly dis- solved, if the iron be soft ; for steel or hard iron will not do. The stream is then Jurned off the pits ; and the men with shovels throw up the copper, which lies on the flag at the bottom, like reddish mud. This mud, being laid in a heap, as soon as dry becomes a reddish dust. It is then smelted into copper. This being the apparatus, the product is thus. One ton of iron in bars pro- duces a ton and IQi cwt. of this copper mud or dust. Each ton of this mud produces, when smelted, l6cwt. of the purest copper, which sell at lOl. per ton more than the copper which is made of the ore. There are about 500 tons of iron now laid in these pits ; and the proprietors may, with proportionable advantage, lay in many thousands. The water that runs from these mines, VOL. X. O o 281 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. enters the river Arklow on New Bridge ; and is of so corrosive a nature, that no fish can live in this large river from hence to the sea. LXXXF. Extract of a Letter to Dr. Maty* F. R. S. from Geneva, con- cerning the Introduction and Success of Inoculation in that City. p. 503. In September 1750, the practice of inoculating the small-pox was first intro- duced into Geneva. The example was set by a young lady ; and was, the next year, followed in the hospital of foundlings, where it was admitted by an order of the governors, and authorized by the magistrates. Their method of doing it was generally the same as that now commonly used in England ; whence instructions were sent to Geneva, when they first began to inoculate. Yet 3 persons were inoculated in a new manner. These were blistered slightly, by means of a small vesicatory applied to that part of the arm, where the incision is usually made. The blister occasioned by this plaster was opened, and a pledget dipped in the pocky matter was applied to the excoriated part. In one instance the incision was made only in one arm ; the success of which was the same, as when it had been made in both. Some pocky matter was made use of, which had been kept 3 weeks ; and some that had even been kept 4 months, without any apparent difference in the effects from that which was fresh ; unless it was owing to this, that, in one instance, the small-pox came out 4 days later than the usual time. The experience, which they have hitherto had in Geneva, has suggested to them a conjecture, that the incision ought to be made deeper when the matter has been kept some time. All who have yet been inoculated in Geneva, have recovered ; and the far greater number of them have had but an inconsiderable number of pustules. LXXXVI. A Letter from James Parsons, M. D., F. R. S. to the Rev. Mr. Birch, Sec. R. S. concerning the Formation of Corals, Corallines, &c. p. 505. [As it is now perfectly well ascertained that corals and corallines are really the fabrication, or at least the natural and necessary accompaniments, of animals of the polype tribe, this paper may be considered as of no importance.] * Dr. MaUhew Maty, an eminent physician, was born in Holland in 1718, and took his doctor's degree at Leyden. In ] 740 he settled in England ; and in 1750 he comraenced a work, published every 2 months, called Journal Britannique, which gave an account of the chief productions of the English press. In 1758 he was elected f. r. s. and in 1765 he succeeded Dr. Birch, as Secretary to that learned body. He died in 1776', leaving one son, the Rev. Paul Henry Maty, who also was afterwards Secretary of the r. s. Dr. Maty was likewise one of the librarians of the British Mu- seum J and he wrote the Memoirs of the Earl of Chesterfield, prefixed to that nobleman's miscella- neous works, in 2 vols. 4to, VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 283 LXXXVII. A farther Account of the late Plague at Constantinople, in a Letter from Dr. Mackenzie, of the 23d of April, 1752. p. 514. As a corollary to his former account sent to Dr. Mead, Dr Mackenzie sub- joins that, on January 3, 1732, there was an accident of the plague, when the thermometer was at 53. Jan. 24, another accident, therm. 62. Jan. 26, an accident at Buiukdere, therm. 51. Feb. 8, accidents at Cassim, Pacha, and Phanar, therm. 52. Feb. 10, an accident in Galata, therm. 55; patient re- covered. Feb. 15, another accident in the same house, therm. 53. March 8, an accident in Galata, therm. 56 ; and not one accident afterwards, though at the above date the thermometer was at 50, and had been at 44 the l6th instant ; so that they had great hopes to get clear, if no infection should be conveyed to them from any other quarter. Prosper Alpinus observes, that the etesian winds at Cairo remove the plague entirely ; so that they fear nothing after these winds begin. And Dr. M. was assured that all the plagues which had been at Smyrna and Constantinople for the last 20 years, had been most violent during the season of the etesian winds; still allowing that were it not for the etesian winds, the plague would be more violent in the hot months. LXXXFIII. A Letter of Mr. James Short, F. R. S. to the Royal Society, con- cerning the Inventor of the Contrivance in the Pendulum of a Clock, to pre- vent the Irregularities of its Motion by Heat and Cold. p. 517. Soon after the invention of pendulum-clocks, justly ascribed to the celebrated Huygens, it was found that they were liable to considerable inequalities in their motion ; which were imagined to rise from the pendulum, in its vibrations, de- scribing an arc of a circle , and consequently that the larger vibrations must be slower than the shorter ones. In order to remedy this imperfection, Mr. Huygens wrote a treatise, called Horologium oscillatorium, a piece of geometry which does honour to the last century, in which he demonstrates, from the pro- perties of the cycloid, that the vibrations of a pendulum, moving in a cycloid, would be performed in equal times, even though the vibrations were unequal. Pendulums therefore were made to vibrate in a cycloid ; but great inequalities were still observed in the motion of clocks. We do not read of any attempts after this, to regulate the motion of clocks till the year 1720, when Mr. George Graham delivered into the Royal Society a paper, which is published in the Phil. Trans. N" 392, in which he says, that it having been apprehended, that the inequalities in the motion of clocks arose from a change of length in the pendulum, by the influences of heat and cold, he, about the year 1715, made several trials, in order to discover, whether there 002 •284 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. was any considerable difference of expansion between brass, steel, iron, silver, &c. when exposed to the same degrees of heat ; conceiving that it would not be very difficult, by making use of two sorts of metals differing considerably in their degrees of expansion and contraction, to remedy in great measure the irregula- rities, to which common pendulums are subject. He says also, that from the experiments he then made, he found their differences so small, as gave him no hopes of succeeding that way, which made him leave off prosecuting this affair any more at that time : that, some time after, having observed an extraordinary degree of expansion, by heat, in quicksilver, he thought of a proper manner of applying a column of it to the pendulum of a clock, in order to prevent the in- equalities arising from its different lengths by the effects of heat and cold; which succeeded accordingly, and is what is now called Mr. Graham's quicksilver- pendulum. Mr. Graham, in the same paper, takes notice, that, though the pendulum of a clock was to remain invariable, yet there would still be some irre- gularities in the motion of the clock, arising from the friction of the different parts of the clockwork, and from the different degrees of foulness. In the year 1725, Mr. John Harrison,* of Barrow in Lincolnshire, made se-. vera! experiments on wires of different metals, to find their different degrees of expansion and contraction : for he thought, that by a proper combination of wires of two different metals, differing considerably in their expansion and con- traction, he might be enabled to keep the centre of oscillation of a pendulum al- ways at the same distance from the point of suspension. In consequence of these experiments, he made a pendulum consisting of one steel wire, at the end of which is the ball or weight, and on each side of this wire 4 wires alternately brass and steel, so disposed and contrived, as to raise the pendulum the same quantity as it is lengthened by heat, and to let down the pendulum in the same proportion as it is raised by cold. He made also a drawing of a clock, in which the wheels are disposed in a different manner from those then in use ; which drawing Mr. S. has seen, signed by himself in the year 1725. Two of these clocks with pendulums, as described above, were finished in the year 1726. In these clocks Mr. Harrison has made a particular sort of pallets, so as to be al- most entirely free from friction ; for though he had thus happily succeeded in his * Mr. John Harrison, an ingenious clockmaker, was born in l693, at Foulby in Yorkshire, and bred to his father's business, that of a carpenter. Having a good mechanical turn, particularly for wheelwork, he constructed some wooden clocks, the accuracy ofwhich was so much admired, that in 1728 he came to London with a drawing of a timekeeper, which he showed to Dr. Halley, who recommended him to Mr. Graham, from whom he received great encouragement to prosecute his design. In 1735 he visited London again with a complete machine, with which he was sent on a voyage to Lisbon by the board of longitude, to make trial of its properties. From that time he went on improving hislnvention, and at length received the reward of more than 20,0001. allowed by parliament for the discovery of the longitude. He died in 1776", at 83 years of age. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 285 contrivance to prevent the inequalities in the motion of the clock, arising from the different lengths of the pendulum by the effects of heat and cold, yet he found there were considerable errors still remaining, occasioned by the friction of the pallets, as in the common way. He also suspended the pendulum on the wall of the house, entirely independent of the clock, and clock-case : for he had ob- served considerable alterations in the going of the clock, when the pendulum is suspended as in the common manner. His pendulum vibrates in an arc of about 15 degrees, with a ball of about 3 lb. between cycloidal checks, which he him- self found were necessary; though he had never heard of Huygens's book, till after he had made them. He has also disposed the force of his pendulum-wheel on the pendulum, by his sort of pallets, in such a manner, that the vibrations of the pendulum will not be aflected by the different resistance of the air. On the whole, this clock is made in such a manner, as to be almost entirely free from friction ; in consequence of which he uses no oil, and therefore there is no ne- cessity ever to clean the clock. When he settled in London, he sent for one of these clocks from the country, and set it up in his house in Orange-street, in the year 1739, where it has stood ever since, and in all that time has never va- ried above one minute from the truth. He can depend on it to a second in a month. About the year 1729, Mr, Harrison made his first machine for measuring time at sea, in which he likewise applied this combination of wires of brass and steel, to prevent any alterations by heat and cold. In 1746, he went on board one of his majesty's ships of war with this machine to Lisbon, and returned, where this machine was publicly shown. Since that time, he has made two more of these machines or clocks for keeping time at sea, in both which he has like- wise this provision, to prevent the effects of heat and cold. An account of these and of the many contrivances which Mr. Harrison has made use of in them, for answering their intended purpose, and an account of the success of his voyage to and from Lisbon, is contained in a speech of the President Martin Folkes, Esq. on his delivering to Mr. Harrison the gold medal of Sir Godfrey Copley ; which speech is inserted in the minutes of the Society in 1749. Mr. John Shelton, who was the principal person employed by Mr. Graham in making astronomical clocks, informs, that Mr. Graham, in 1737, made a pendu- lum consisting of 3 bars, viz. one of steel, between two of brass, and that the steel bar acted on a lever, so as to raise the pendulum, when lengthened by heat, and to let it down, when shortened by cold. This lever, which is very strong, rests on a roller, made moveable, so as to adjust the arms of the lever to their true proportion. The whole was made to be as free from friction as possible in such a construction. Mr. Graham made observations, by transits of the fixed stars, of the motion of the clock with this sort of pendulum, and from the ex- 286 PHILOSOPHICAL TRANSACTIONS. [annO 175 J. perience of several years, during which the clock was kept constantly going, he found that the clock was liable to sudden starts and jerks in its motion. Of this he informed Dr. Bradley, Mr. Bliss, Mr. S. and several other gentlemen. This clock still remains in Mr. Graham's house, in the possession of his executors. Mr. S. had been informed, that one Mr. Frotheringham, a quaker, of Lin- colnshire, caused a pendulum to be made, consisting of 2 bars, one of brass, and the other of steel, fastened together by screws, with levers to raise or let down the ball ; and that these levers were placed above the ball. This clock Mr. S. had seen, and was told by the maker, Mr. John Berridge, that the pendulum of it was made in 1738 or 1730, and that the dial-plate of it was engraved at Mr. Sisson's house in 1738 : and this clock is in the possession of Mrs. Gibson, in Newgate-street, who has had it ever since the year 1739- In the Hist, of the Royal Acad, of Sciences at Paris, for 1741, there is a me- moir of M. Cassini, in which he describes several sorts of pendulums for clocks, compounded of bars of brass and steel, and applies a lever to raise or let down the ball of the pendulum, by the expansion or contraction of the bar of brass. He has also given in the same memoir, a problem for finding the proportion which the two arms of the lever should have, to answer the intended purpose ; and also a demonstration of it. In June, 1752, Mr. John Ellicot gave in to the Royal Society a paper, con- taining the description of a pendulum, consisting of 2 bars, one of brass, and the other of iron, fastened together by screws, with 2 levers in the pendulum ball, so contrived as to raise and let down the ball, by the expansion and con- traction of the brass bar ; and also to adjust the arms of the levers to their true proportion.* He says, that he first thought of these methods of applying bars of brass and iron to prevent the irregularities of a clock, arising from the dif- ferent lengths of the pendulum, by the effects of heat and cold, in 1732; and that he put his thought in execution in 1738. In 1743, Mr. S. bought a clock of Mr. Graham, which he had kept going for 2 years before. This clock has a pendulum, compounded of wires of brass and steel, in the manner of Mr. Harrison's combination. It has also a provision in the ball, to adjust the wires, in case they happen to be too long. When Mr. S. first took notice of this contrivance or provision in the ball, he asked Mr. Graham the reason of it ; who told him, that having observed some inequalities in the motion of the clock, he imagined that they arose from the wires being somewhat too long ; and therefore added this contrivance, to adjust the length • He has also given, in the same paper, another constmction of a pendulum to prevent the effects of heat and cold, consisting of 2 bars, one of brass, and the other of iron ; the brass bar acting on a lever, at the end of which is fastened the pendulum, the whole so constructed and contrived, as to raise the pendulum, when it is lengthened by heat, and to let it down, when shortened by cold. — Orig. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 287 of the wires ; but that when he had done this, he found inequalities still re- maining; and therefore justly concluded, that they arose from the difference in the friction of the different parts of the clockwork, occasioned by the differences in the fluidity of the oil, &c. From what has been said above, it appears, that the improvement of clocks, by a contrivance to prevent their inequalities arising from the different lengths of the pendulum, in different seasons of the year, by the effects of heat and cold, was first thought of, and executed, by Mr. George Graham ; and that the ap- plication of wires or bars of two metals, which have different degrees of expan- sion or contraction, to prevent the same inequalities, was also first thought of by Mr. Graham, and first executed by Mr. John Harrison, without the least know- ledge of what Mr. Graham had done before him. LXXXIX. On the Cause of Thunder. By Mr. Henry Eeles, dated Lismore, Ireland, June 18, IJb'i. p. 524. Mr. Eeles's opinion on the cause of thunder is, that it is by electrical explo- sions among the clouds, the fire of lightning and electricity being of the same nature, as had been long before proved by the experiments of Mr. Franklin in America. After the explosion, then the echo of it from the other clouds is the cause of the continued or distant rumbling noise. Mr. E. adds, that he intends afterwards to show, that this fire is a most considerable agent in nature. First, that the ascent of vapour and exhalation is principally owing to it, and that our atmosphere, by that means, is kept more homogeneal than is generally supposed, and fitter for respiration, vision, &c. and that clouds of heterogeneous matter are kept suspended at their usual height merely by this fire. Secondly, that this fire is the cause of the reflection, refraction, and inflexion of light. Thirdly, that it is the cause of that secondary attraction and repulsion, which Sir Isaac Newton has taken notice of. Lastly, he will give some hints of the great use of this fire in animal life, and in vegetation. XC. On Mons. DavieVs Method of Couching a Cataract. By Thomas Hope, M. D. p. 530. Dr. H. states that he had heard of a new method of performing the operation for the cure of the cataract, but did not care to say any thing of it, until he had seen it himself, and had inquired into the success of it. M. Daviel, a surgeon of Paris, was the first who, in 1745, began to put it in practice, and had at last brought it to perfection ; of which he gave a memoir to the Academy of Sci- ences, of 115 operations, 100 of which succeeded. Dr. H. saw him perforin it on 2 persons, of which the following is a description. After having placed the patient in a right light in a chair, he places himself 288 PHILOSOPHICAL TRANSACTIONS. [aNNO 1751. over-agalnst, and somewhat higher than the patient : an assistant holds the head steady, another keeps the upper eye-lid open ; he, with his left hand, keeps open the lower eye-lid. He then takes an instrument like a lancet, of a myrtle- form point, a little crooked upwards, and fixed in a handle, and, making the patient look upwards, he pierces the cornea transparens at its lower circumfe- rence, just where it joins the sclerotica, conveys the point of the instrument between the cornea and iris upwards, beyond the pupil ; he enlarges this open- ing on each side by the same instrument : he then takes out this instnmient, and introduces another of the shape of a narrow lancet, made round at the point, fixed in a handle : with the cutting sides of this he enlarges the opening. Tak- ing out this, he introduces a pair of crooked scissars, enlarges the opening on each side by different snips, always as near as he can to the circumference of the cornea transparens, till he has made the opening round two-thirds of the cornea transparens : he then takes out the scissars, and, with a small instrument like an ear-picker, he raises the cornea, and having in his right hand a cataract-needle, broader and stronger than the common, and pointed like a lancet, he cuts the capsula of the crystalline through the pupil ; then, pressing gently the globe of the eye with his finger from below upwards, the crystalline slips out of the cap- sula, and drops out of the eye. On the first puncture, the aqueous humour coming out, the cornea and iris join together : and it requires great dexterity, and a very steady hand, to introduce the instruments so as not to wound the iris, which would endanger the eye. Though the operation lasted above 2 minutes, the patient never complained of any pain ; and said he felt nothing but a tickling. By which it appears the cor- nea is not much more sensible than the nail of one's finger. And this operation, which seems so cruel to a by-stander, does not give so much pain as couching in the usual manner. It is to be preferred to couching in many respects. It may be performed at all times, and in all kinds of cataracts, whether they are come to maturity or not. It also avoids many inconveniencies and accidents, which often baffled the success of the best operations ; such as the rising again of the cataract, violent defluxions and inflammations, which often destroyed the eye, the hurting of the vitreous humour, which seldom failed in couching, &c. In both the operations, which Dr. Hope saw, the patient, immediately after^ could distinguish all large objects in the room. M. Daviel says, that he has found by experience, that all those instruments are necessary : and as to the extent of the incision, he says that he seldom makes it above one-half of the circumference of the cornea transparens; and that a smaller opening would not suffice to let the crystalline slip out easily ; the dia- meter of which, in general, not being above a line less than that of the cornea, and in some cases within half a line, insomuch that, in order to make it pass VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 289 through the pupilla, he has been obliged to give a snip of the scissars to the iris, which he says is attended with no bad consequences. In answer to what is said, that it has been practised before, and that Taylor formerly performed it, he endeavours to prove, that it never was, excepting in cases where the crystalline had, by some accident, slipt through the pupilla into the anterior chamber. In regard to the operation, there is some mention made of it among the Arabians, as what they had heard of; but the operation is not described particularly any where. One convincing reason, that it never was carried into practice among the ancients, is, that had they made the extraction of the cataracts, they must have found it to be the crystalline humour, and not remained in the error they have all fallen into, that the cataract was a mem- brane formed in the aqueous humour. In regard to Taylor, he may have attempted, but never did carry it into prac- tice ; else he would not have failed to have published it in the numberless productions he has given. Dr. H. knows that, in 1743, he followed him in Edinburgh for 6 months, where he performed above 1 00 operations of the cata- ract by couching ; but never once attempted this way, nor ever mentioned it, but in the case where the crystalline is lodged in the anterior chamber ; which ope- ration has been described in many authors. So that he thinks, Mr. Daviel may be truly said to be the first, who had brought this method into general practice for the cure of a cataract. Dr. H. thinks, the greatest risk one runs in this operation, is the pushing out of the humours of the iris through the opening, which forms a staph)loma ; and he finds this has been the case in some of those that have failed ; and it is not easy to contrive a bandage on that part, to make a compression equal to the re- sistance of the cornea before it was opened. XCI. Letters of the Abbe Mazeas, F.R.S. to the Rev. Stephen Hales, D.D., F.R.S. on the Success of the late Experiments in France, concerning the Ana- logy of Thunder and Electricity. Translated from the French by James Parsons, M.D., F.R.S. Letter 1, dated St. Germain, May 20, 1752, N. S. p. 534. The Philadelphian experiments which Mr. Collinson communicated to the public, having been universally admired in France, the king desired to see them performed. Therefore the Duke d'Ayen offered his majesty his country-house at St. Grermain, where M. de Lor, master of experimental philosophy, should put those of Philadelphia in execution. His majesty saw them with great satis- faction, and greatly ajjplauded Messieurs Franklin and Collinson. These ap- plauses of his majesty having excited in Messieurs de Buftbn, D'Alibard, and De Lor, a desire of verifying the conjectures of Mr. Franklin, on the analogy VOL. X. P P 'igO PHILOSOPHICAL TRANSACTIONS. [anNO 175'2. of thunder and electricity, they prepared themselves for making the expe- riments. * M. d'Alibard chose, for this purpose, a garden situated at Marly, where he placed on an electrical body a pointed bar of iron, of 40 feet high. On the 10th of May, 20 minutes past 2, afternoon, a stormy cloud having passed over the place where the bar stood, those that were appointed to observe it, drew near, and attracted from it sparks of fire, perceiving the same kind of commotions as in the common electrical experiments. M. de Lor, sensible of the good success of this experiment, resolved to repeat it at his house in the Estrapade at Paris. He raised a bar of iron QQ feet high, placed on a cake of resin, 2 feet square, and 3 inches thick. On the 18th of May, between 4 and 5 in the afternoon, a stormy cloud having passed over the bar, where it remained half an hour, he drew sparks from the bar. These sparks were like those of a gun, when, in the electrical experiments, the globe is only rubbed by the cushion, and they pro- duced the same noise, the same fire, and the same crackling. They drew the strongest sparks at the distance of g lines, while the rain, mingled with a little hail, fell from the cloud, without either thunder or lightning ; this cloud being, according to all appearance, only the consequence of a storm, which happened elsewhere. From this experiment they conjectured, that a bar of iron, placed in a high situation on an electrical body, might attract the storm, and deprive the cloud of all its thunder. I do not know. Sir, whether Mr. Franklin's letters were before your conside- ration on earthquakes : if they were, we are obliged to Mr. Collinson for his communication of Mr. Franklin's notions ; if they are not, you deserve the honour of the discovery ; and whoever it be, it is still to the r. s. we owe the communication of this ingenious thought, which the experiments ofM. d'Alibard and M. de Lor have confirmed. These 2 learned men deserve that esteem of our nation which their talents have a long time procured them. Letter 2. Dated St. Germain, June 14, 1752. — M. le Monnier, having prepared to repeat the same experiments, avoided that inconvenience in the resin cakes being wetted by the rain. He placed, in the garden of the hotel de Noailles, a wooden pole, of about 30 feet high, at the end of which was fixed a large glass tube, which received at the other end a long tin pipe ; and this pipe received again, in its turn, a pointed bar of iron, of about 6 feet high. The glass tube was instead of the cake of resin, to hinder the communication of the electricity from the tin pipe to the pole. A wire was carried from the bar of iron, which rested on a silken cord, about 50 paces from the pole ; but rain coming on, the wire was conducted into the house. We perceived the commo- tions of the electrical matter from the first clap of thunder ; it produced sparks, and there were certain intervals, when the commotions were so strong, that they VOL. XLVn.] PHILOSOPHICAL TRANSACTIONS. . , 2gl were accompanied with very sharp pain. It seemed as if the commotion was the greater, the nearer the thunder was to the bar. Letter 3. Dated St. Germain, June 20, 1752. — On the 26th of this month there was a storm at two different times : the 1 st was at 3 in the afternoon, and the second at half after 6. This storm, which came from the south-west, was very inconsiderable : there were but 2 or 3 claps of thunder, either at 3 or at 6 o'clock. ; and there was a considerable interval between the lightning and the clap, which showed that the thunder was at a great distance. Yet the effects of the electricity were very violent, which we attribute to M. le Monnier's ingenious apparatus ; which was as follows : It is certain that the greater the quantity of these bars, the greater is the quantity of electricity furnished by the magazine. In the last experiment there was a tin pipe of 7 feet long, and about 5 inches diameter. It was the 1 st ma- gazine : the 2d consisted of 6 great bars of iron of 6 feet long each, placed in parallel order on glass bottles. All these magazines communicated with the iron wire, that descended from the little bar at the top of the great pole, des- cribed in the last letter. The 26th of this month, at 3 afternoon, very lively sparks were excited, and M. le Monnier set fire to spirits of wine. At 6 o'clock the Abbe M. went up to a proper place, in order strictly to observe the intervals between the commo- tions and the electricity. The clouds extended from the south and west to the zenith of the pole, and the lightning came from a very distant part ; and, in proportion as the clouds came nearer, the electricity was felt with very smart shocks, but without light or regularity ; for sometimes none were felt for 2 or 3 minutes, and it was commonly with every flash of lightning that the commotion was felt. But when the clouds had covered a considerable part of the heavens, the commotions of the electricity succeeded very quickly with noise and sparks ; though the thunder could scarcely be heard, because of its distance. It may hence be judged how strong the commotions would be, if the clouds, which produced the thunder, were nearer the bar. On June 2g there was another storm ; but the Abbe was not present at the experiments made in the garden, being employed in a like experiment in his chamber. He placed at his window, which was about 35 feet from the ground, a bar of iron of 12 feet long, which received a very sharp iron wire of 6 feet high ; the whole advanced into the street, by means of a wooden pole laid pa- rallel to the horizon ; at the end of which was a glass tube filled with resin, to receive the iron rod. The wire that hung from the extremitj' of the pole entered into the chamber, and from thence into a gallery of 30 feet long. The electri- cal magazine was in his chamber, and the iron wire, after several turnings, was again brought thither. He had disposed of this wire in such a manner, that if p p 2 2Q'2 PHILOSOPHICAL TRANSACTIONS. [anNO 1752. tlie stonn should come in the night, or if it happened by day, lie had it in his power to observe all he proposed, without quitting his befl tir his business. The storm came at 5 in the oening ; and though he had not )"et time enough to Ibnn a sufficient magazine of electricity, Ik? had nevertlieless v-er}' satisfectory signs. TIte person who held the iron wire felt a conunotion ; and at the same instant silken ribands were attracted by the electrical niagazinr. There came on a great shower of rain and hail, which wetted tlic resin in the glass tube that supported tl>e bar; ami after tliat tl>ete were no more signs of electricity. T^e same thing happened in the garden ; where the silken cords, which in several places interrupted the communication of tite electrized bodies with the non- elcctrif^, having been wet, sensibly diminished the desirvd efFcct. The electri- city howc\-er was very strong before the rain fell ; and the conunotions wx're felt at about a foot distance : but the storm only passed by, and lasted no more i the whole than 1 or 3 minutes. Letter 4. Dated St. C«rawra, Jul^ \1, I75'2.— M. le Monnier, who per- formed the experimcmts, was oonvinocd that the higii situation, in which the bar of iron was cuinmonly placed, b not abmlutdy necessary to produce the effects of electricity : for a tin spedking trumpet suspeiKled on silken cords, about 5 or 6 feet from tite ground, Hm pcodooed very particular signs of electricity. A man placed on a cake of resin, and holding with his hand a wooden pole, of about 18 fixi long, round which an in»n wire was twisted, was so well electrized while it thuiMiercd, that very lively sparks were drawn from his 6oe and hands. Having taken away the oonxnunication of the electrical magazine with the iron win*, which himg from the great wooden pole (this magazine consisting, as mentioned in tlic last letter, of 6 great bars of iron, placxxl horizontally on glass bottles, about 4 feet from the ground), this magazine was strongly electrized, when the stormy cloud passed in the zenith. A man standing on the electrical cake in the middle of the garden, and simply holding up one of his hands in the air, attracted with the other haiul wcxxi-shav- ings, which were held to him on a piece of lead. Whence it evidently follows, that the matter which is the cause of all the surprizing phenomena, which elec- tricity affbnls us, fills the atmosphere in the time of a storm ; that it j)enetrates us ; that we breathe it with the air ; and tliat the height usually given to the iron bar, only serves to intercept the &r greater quantity of the electrical matter. At the time that M. le Monnier made his experiments, the Abbe, in his turn, trieti to perfect the manner of bringing the electricity into his chamber. He therefore increased tlie length of his wooden pole, which went out of his window, and at the same time that of his iron rod, which was perpendicularly fastened to its end. The greater the lengtli and height that tliese two were, the stronger was tlie electricity in the chamber. TOL. XLTII.^ PHILOSOPHICAL TIAN8ACTIONS. '1^3 Towanls 1 1 in the morning, the heavens began to be covered to the south- west, with stMne claps of thunder and lightning at a gR^at distance. The AbW had just time to go to the garden, where he found tiie Duke d'Ayen, wlio had p(e|Mured ever)- thing for the experiments. An iron wire descended from the top of tlte pole, and rested on the hot-house of the garden : this wire was supportetl by m silken cord, and was tenninatetl by a tin cylinder, of about 3 inches dia- meter, ami 3 feet long. The electricity of this cylinder was such that, when a finger approached it, 'i or 3 very lively sparks at a time were proilucetl, with a iliarkling noise, like that of the nails of one's fingers crackled against each other. Tlien the Duke d'Ayen took the first shrub he met in the hot-house, which happened to be that from which the labdanum is producetl : he placed it with its pot on a cake of resin, and fastened the iron wire to one of its branches. This shrub was instantly electrized, so tliat whitisli sparks issued from every leaf, witli the same kind of crackling just mentioned ; but the trunk of this shrub had a much stronger electricity ; whether at that instant the electricity of the cloud was more stanig, (for it \-aries every moment) or that the force of the whole electricity, expamled through the leaves, became concentrated in the trunk of this shnib. Tlie duke then took one of his silver watering-pots, which was 24 feet high ; he rilled it with water within an inch of the brim, and placed it on the electrical calie, dipping into it a wire of lead, which communicated with that wire which came from the top of the pole. Of all the electricity tried till then, this was incomparably the strongest; there were 20 sparks; and on advancing the ringer towards it, the shock affected the arms and breast with great violence. Letters. Dated Paris, August 1\, 1732. — A phenomenon, which I have always thought worthy of strict obser\'ation, is the diminution of the electricity of tliunder, when rain comes on during the storm. This diminution was re- market! at St. Germain, every time I was a witness to M. le Monnier's experi- ments ; and the same effect is, within this little while, confirmed to me by the learned Mr. Euler, in communicating to me the observations of M. Ludolf. I left St. Germain the 12th of July to come to Paris, at 7 in the evening. At the instant of my arrival, I saw the heavens covered with clouds, and the light- ning foreboded thunder, which soon was heard. I went up into the gallery of the Hotel de Noailles, which is very high, and distant from the neighbouring buildings : my pole was 10 feet high ; at the end of which a glass tube was made fest ; and to this a very sharp iron spire, from the middle of which a wire of about 20 /eet long came down, and rested on a long glass tube fixed to the ba- lustrade, which environed the galler}-. My apparatus was scarcely ready, when it thundered, and the clouds broke by this first clap, and poured down a conti- 294 PHILOSOPHICAL TRANSACTIONS. [anNO 1752. nual large quantity of rain, which lasted near 1 hours, without the least discon- tinuance of the thunder. I felt no commotion in putting my finger towards the wire, nor could I draw any sparks from it. I was on the point of giving it over, when the wire happened to touch the leads and the balustrade of the gallery ; and it instantly produced as many sparks, as it touched places on the balustrade and leads. I then took the wire in my hand, and threw it strongly against the bars of iron ; and as the wire extended, and successively touched the bars, it always produced the same effect. There were prodigious multitudes of these shining sparks, like those produced by the finger in common experiments. I only wanted an electrical magazine to accumulate electrical matter in, which would have produced me all the usual phenomena. The Abbe then communicates the observations that Mr. Ludolf made at Berlin. ] . That the sparks drawn from the wire were half an inch long ; and they caused so horrible a shock, that the entire body of the person who attracted them, was shaken ; but the small sparks produced only a light sensation in the fingers. 1. It is also remarked, that this electricity communicates itself to all bodies else- where, that are susceptible of it, provided they are placed on electrical bodies, while they are made to communicate by a wire. 3. When there was plenty of rain, they scarcely remarked any thing of the force of the electricity, though the lightning and claps of thunder were very strong. 4. At every clap of thunder the electricity seemed extinct, and returned not till after about 30 seconds, and some- times longer. 5. When the wire was surrounded with drops of rain, it was observed that only some of them were electrical, which was remarkable by the conical figure they had ; while the others remained round as before. It was also perceived, that the electrical and non-electrical drops succeeded almost alternately; which made them call to mind a very singular phenomenon, that happened some years ago to 5 peasants, who passed through a corn-field near Frankfort on the Oder in a storm. The thunder killed the 1st, the 3d, and the 5th, without injuring the 2d and the 4th. 6. The storm of the 1st of August was very considerable, with very great rain every minute they remarked 3 or more flashes of lightning ; in the mean time some electrical sparks were observed on the wire. They put upon a chain, which communicated with the wire, a thread, the 2 ends of which hung down ; which showed electricity by mutually repelling each other ; for at every flash of lightning they approached each other suddenly, as if they had been pushed one against the other by some force. 7- Sometimes the electricity con- tinued in the wire with great strength to 45 minutes, after the thunder and lightning had entirely ceased, &c. Conformable to the 6th observation of Mr. Ludolf, the Abbe says he has often observed, that in presenting dust or dried VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. ^QS snufF to the end of a tin cylinder, which hung to the wire in such experiments, this dust was strongly attracted, as soon as the wire showed any signs of electri- city. But when the electrical matter came to be accumulated in this cylinder, the dust was powerfully repelled as by a strong blast, insomuch that the quan- tity of molecules repelled was much greater than of those attracted at the same time. And with respect k) this successive attraction and repulsion, the Abbe men- tions an experiment he was informed of, without knowing that the author of it was Mr. Franklin. The dishes of a pair of scales were suspended to the balance by silken cords ; the two dishes were electrized, and a very sharp needle was presented to one of them. The scales immediately lost their equilibrium ; and that dish under which the needle was held was attracted. The direct contrary happened, when an obtuse or round body, such as a leaden bullet, was put on the point of the needle, for then the dish was repelled. If this experiment be true, it strongly imitates what happens in the clouds, when they are in equilibrio in the atmosphere : and it gives room to conjecture, that it would be much less dangerous to tenninate the tops of steeples with obtuse bodies, than with pointed spires, on which the thunder falls, sooner or later, when they are very high. XCII. On Extracting Electricity from the Clouds. Translated from the French, by the Abbe Nollet, F.R.S. Dated Paris, June 6, 1752. n. s. p. 553. The Abbe, after having taken notice of the discovery of M. d'Alibard in France, in regard to extracting electricity from the clouds during a thunder- storm, in consequence of Mr. Franklin's hypothesis, observes that he is piore interested than any one to come at the facts, which prove a true analogy between lightning and electricity ; since these experiments establish incontestably a truth, which he had conceived, and which he ventured to lay before the public more than 4 years ago. Examine the 4th volume of his Leqons de Physique, p. 314, and you will find what follows : ' If any one should take upon him to prove, from a well connected comparison of phenomena, that thunder is in the hands of nature, what electricity is in ours ; that the wonders which we now exhibit at our pleasure, are little imitations of those great effects which frighten us ; and that the whole depends on the same mechanism ; if it is to be demonstrated that a cloud, prepared by the action of the winds, by heat, by a mixture of exhala- tions, &c. is opposite to a terrestrial object ; that this is the electrized body, and at a certain proximity from that which is not ; I avow that this ideji, if it was well supported, would give me a great deal of pleasure ; and in support of it how many specious reasons present themselves to a man who is well acquainted with electricity ! The universality of the electric matter, the readiness of its action, its inflammability, and its activity in giving fire to other bodies ; its poverty in 296 PHILOSOPHICAL TRANSACTIONS. [aNNO 1752. striking bodies externally and internally, even to their smallest parts ; the re- markable example we have of this effect in the Leyden experiment ; the idea which we might truly adopt in supposing a greater degree of electric power, &c. all these points of analogy, which I have been some time meditating, begin to make me believe that one might, by taking electricity for the model, form to oneself, in regard to thunder and lightning, more perfect and more probable ideas, than what have been offered hitherto, &c.' To demonstrate, that glass is not absolutely impermeable to the electric fluid, the Abbe offers the following experiment : Let the neck of a small thin phial a, fig. 1 5, pi. 6, be placed in that of the receiver b ; and lute it in such a manner, as that the air cannot pass through their joining. Exhaust the receiver, and pour the little phial 3 parts flill of water, and conduct the electricity into it by means of an iron wire, suspended to the conductor. Make the experiment in a dark place, and for the greater surety fix the receiver to the plate of the air- pump, not with wet leathers as usual, but with soft cement. You will see the electric matter pass, as through a sieve, through the small phial into the receiver, and present itself in an infinite number of luminous streams, of extraordinary beauty ; and if you do not take care you will be smartly shocked, as in the Ley- den experiment, by laying one hand on the receiver, and touching the plate of the air-pump with the other. To prove that in the Leyden experiment the electrical virtue, or power of giving a shock, does not reside only in the glass, make the following experiment: Electrize a phial two-thirds full of water ; pour this water into another thin phial, placed on a glass stand ; plunge an iron wire into it, and attempt, while the phial is in one hand, to draw a spark with the other : it is certain that if this is done with a little readiness, you will make the Leyden experiment with this water.* Possibly you may not always succeed with water ; but with mercury, under the same treatment, it never fails. Whence proceeds the power of giving the shock to the second glass, if it is not by means of the water, which it has received ? Electrize a bolt-head of glass, void of air, and sealed hermetically ; you may make use of it for the Leyden experiment, and you will succeed. Is there not then a communication between the exterior and interior surface of the glass ? And is it not evident further, that the electric matter, which is perceived running >vithin like a torrent of fire, passes through the glass ? * Some years ago I showed this experiment to several members of the r. s., and not only produced the Leyden experiment with it, but by pouring the electrized water into a basin, held in one hand of an assistant standing on cakes of wax, who, on his presenting a finger of his other hand to some warm spirit of wine in a spoon, held in the hand of a person standing on the floor, set it on fire. I then considered this experiment as a proof of the electricity being accumulated in the water. W. Wat- son.— Orig. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 207 When you force a hole through a piece of paper or pasteboard, attend to one thing, which I constantly observe. If you electrize the plate of glass, ab, fig. 15, underneath, and that, by means of a thick iron wire somewhat bent, d, you draw the spark through a piece of pasteboard, c, placed on the metal, with which the glass is coated, the hole will appear invariably larger underneath, than on the top of the pasteboard ; and this hole will have an impression at the place where the iron wire shall have been supported. These 1 etFects leave no room to doubt, but that the stroke of fire was directed from the glass to the conduc- tor, E, by the bent iron wire. Besides, if the electric fire proceeds from the upper surface of the glass, which receives the electricity from the under surface, it necessarily follows, that it must have passed through the whole thickness of the plate of glass ; and consequently that the glass is not impenetrable to the electric fluid. The electrical experiments, which have been made here during the thunder, are now sufficiently verified. Dr. le Monnier, assisted by his advantageous situ- ation, has sufficiently experienced, first, that a bar of iron, pointed or not, is electrized during a storm : 2dly, that a vertical or horizontal situation is equally fitting for these experiments : 3dly, that even wood is electrized : 4thly, that by these means a man may be sufficiently electrized to set fire to spirit of wine with his finger, and repeat almost all the usual experiments of artificial electricity ; for thus the Abbe denominates that which is excited by friction. Seeing therefore that these experiments succeeded so well, he attempted them at Paris with a tube of tin, 18 feet in length, and of an inch and half in diame- ter ; half of which tube he put out of the window, while the other half was placed on, and fastened to, silk lines : and though he lived in the lowest part of Paris, and his apartment in the Louvre is covered with an immense building, both in height and extent, at any time when the thunder was but moderate, he per- ceived signs of electricity. The sparks were more frequent after the lightning than after the thunder ; and it even seemed that the clap of thunder put a stop, for a very short time, to the force of the electricity. Mons. Cassini de Thury, who was desirous of observing these effects with the apparatus which they had erected on the terrace of the observatory, made the same remarks ; and he has had a greater opportunity of observing them, because the effects there were more considerable, on account of the situation. He even remarked very evident signs of electricity, though there was neither lightning nor thunder, but only the sky covered with such thick clouds as seemed to fore- bode a storm. Mons. le Roy, a member of the Academy of Sciences, who lives near the Abbe, has repeated also a great number of these experiments and observations VOL. X. Q Q 298 PHILOSOPHICAI«.iTRANSACTIONS. [anNO 1752; by only making use of a pole of wood 25 feet long, about which he turned an iron wire in form of a screw. XCIII. Extract of a Letter from Mr. Mylius of Berlin, to Mr. W. Watson, F.R.S., on the before-mentioned Subject. Dated at Berlin, August 26, 1752. p. 559. March 16 last, at a little past 8 in the evening, we had here a slight earth- quake, which manifested itself by its shaking the ground, the windows, and by opening some doors. This we have had no example of before in our country ; and it was perceived at the same time at Stavanger in Norway. I have made experiments of collecting the electricity, during a thunder-storm, with great success, in company with Professor Ludolf. He had erected an iron bar, of 12 feet long, which was fastened on a pole of wood, 50 feet in height, with 2 tubes of glass covered with tin. The upper end of the iron bar was sharp pointed, and near the lower end was fastened a very long iron wire, which being carried into a summer-house, gave great sparks, as the thunder was approaching ; and these sparks caused sometimes as violent a shock through the body, as the experiment of Leyden. It was also continually observed, that the effects were greatest, when the lightning was nearest ; and that for some moments after the lightning, the effect ceased, but returned and increased by degrees. XCIP . Mans. FageCs Remarks on the Use, &c. of the Styptic, purchased by . his most Christian Majesty. Communicated by James Theobald, Esq. F. R. S. p. 560. About the end of the year 1750, Mr. Brossard, a surgeon from Berry, came to Paris, to propose the use of a remedy, which he had discovered for stopping the blood after amputations, and which he asserted to have found effectual in several amputations of the arms and legs. At his request, some gentlemen of the Academy of Surgery were deputed, in whose presence he was to make some new experiments in stopping the blood on different animals, and in all which he succeeded, by slopping it in the largest arteries after amputation. But the suc- cess of this remedy might yet be considered a little dubious, because in many animals, as in dogs particularly, the great arteries stop of their own accord ; and rarely any dogs die from an haemorrhage, because their blood is more disposed to coagulate, and by that means stop the discharge. For this reason the experiments made on animals not being thought satisfactory, and yet being convinced that no ill effect could follow the application of this remedy on human kind, Mr. Bros- sard was permitted to use it at the Hospital of the Invalids, in an amputation of the leg, which succeeded perfectly well. VOL. XLVIT.] PHILOSOPHICAL TRANSACTIONS. 2Qg Some time after this 2 waggoners were run over by a waggon loaded with stone, and each of them had one leg broken in a miserable manner. These 2 men being brouglit to the Hospital of the Charity, Mons. F. saw no other hopes of success but in amputating the legs ; and therefore he requested Mr. Brossard would be present, and give a proof of this new application, which they applied in the following manner : As soon as the leg was cut oft', he slackened the tourne- quet, to discover the vessels ; and Mr. Brossard applied, on the orifices of the 2 arteries, 2 pieces of his astringent, fastened one on the other with a ribband. After tlie application was made, Mr. F. straitened the tournequet, and passed the 2 ends of the ribband, which was fastened to the upper piece of the astringent, on the stump over the knee, and applied a linen bag, filled slightly with the same astringent in powder, on the whole wound ; and over all applied the com- mon dressings in the like case. After the dressing was finished, he slackened the tournequet, and 2 hours after took it entirely away. Eight and forty hours after this, they took oft' the dressings, and not the least drop of blood followed from the vessels: and they again applied 1 single piece of the astringent on the 2 vessels ; and he dressed the other parts of the wound with pledgets of lint, with common digestive, a styrax plaster, and the usual bandage. The 3d day the astringent fell off" of itself in the time of dressing ; and the patient, after that time, was dressed in the common manner. The same was done to the other patient, after the amputation, as to this. The first of these men died on the 5 th day, and the other on the Qth : but there did not appear, through the whole, the least tendency to an haemorrhage. Thus the remedy fairly produced its effects, as to the stopping the blood. However, in order to determine the manner in which this astringent produces its effects, he examined the blood-vessels of those 2 patients after their death, and found them contracted and straitened, as if they had been tied, and in the largest of them a conical coagulation of the blood, which was an inch and half long : and after having taken out this coagulation, it was with difficulty that he could introduce the point of a very small probe into the orifice of that vessel. The patient, who died on the Qth day, had the arteries contracted in the same manner ; but with this difference, that the coagulation was at least 4 inches long. Mr. Morand has employed this remedy with success in applying it to a wound, made by a sword in the bending of the arm : and Mr. F. himself had made use of it, with great success, on occasions where the temporal and intercostal arteries had been opened. In the last-mentioned cases, he applied only 1 piece of the styptic on the opening of the artery; and this generally fell off^ at the lirst dressing, that is, 48 hours after the application, without th'.i least appearance of an hicmorrhage, or other ill symptoms, which could raise any objection to this styptic i for those patients were all recovered. aa2 300 PHILOSOPHICAL TRANSACTIONS. [aNNO 1752- There had been lately made, at the Hospital of the invalids, 1 experiments of this astringent in amputations ; and in both the success has been equal to all that can be desired. The surgeon, in these cases, used only the 1 pieces, applied one over the other, without using the powder in the bag, as before ; and dressed the whole wound with lint and the common bandage. - Thus then at last there appears to be discovered a remedy beyond our hopes, and which art has never yet equalled. The application of fire was the cruel re- source of the ancients ; and Pare believed himself inspired when he discovered the use of the ligature. But, alas ! how many accidents are there, which arise from the use of those 2 manners, and which too often terminate in the death of the patient ! Happy for us, that those accidents now appear to be no longer to be feared, by the lucky discovery of this styptic, the first experiments of which have so greatly promised success 1 It may be remarked, that, if this astringent succeeded only in coagulating the blood, it had produced nothing extraordinary ; for these coagulations would not have been sufficient to have stopped the haemorrhage, directly after the opera- tion in amputations : but its excellency lies in contracting the arteries so closely, that it hardly lets a little probe into the aperture of the artery, and by this means forms, as it were, a perfect ligature, much more certain than the usual one ; as this is not made in any one point of the cylinder of a vessel. Thus this appli- cation exceeds every thing which has hitherto been produced by the operation of our hands.* • This singularity in the operation of this remedy supposes another in the vessels, which is the great contractility of the fibres of the arteries. These indeed do naturally contract of themselves ; but not to two-thirds of their dia- meter ; nor to that state in which they are straitened by the effect of this as- tringent ; because, by that the whole aperture is almost entirely taken off in the largest vessels ; and it is easy to imagine their effects in the smallest. It may be observed, that it is not in the dead parts of bodies, that this con- traction can be made : it requires the assistance of the vital principle, and operates on the fibres by certain articles contained in it, which dispose the animal body, by its irritation, to shorten its fibres, and reduce the tissue, which they compose, into a less volume. This remedy is nothing else but the agaric of the oak. The best kind of it is found on the parts of oak trees, where the large limbs have been cut off; and it very often resembles a horse-shoe in its shape. This agaric is distinguished into 4 parts: the rind; the 2d part, which is preferable to the other; the 3d part * In a subsequent number of these Trans, we shall take occasion to remark that notwithstanding all that has been advanced in favour of this and other styptics, the best method of stopping a haemor- rhage when a large artery is divided, is to have recourse to a ligature. VOL. XLVII.] PHILOSOPHICAL TRANSACTIONS. 301 serves for the stopping the blood in the smaller vessels, as well as that part which touches the tree. This last was what was powdered, and applied in the little bag, as in the operations of the charity. The 2d part is what Mr. F. makes use of in amputations, cut into pieces. It must be beaten by a hammer till it is soft; and this is its whole preparation. Every part is prepared alike. The best time of collecting it Mr. Brossard has found to be in the autumn, in fine weather, after great heats. XCV. A Letter from Benjamin Franklin, Esq. to Mr. Peter CoUinson, F.R.S. concerning an Electrical Kite. Dated Philadelphia, Oct. 1, 1752. p. 565. As frequent mention is made in the public papers from Europe, of the success of the Philadelphia experiment, for drawing the electric fire from clouds by means of pointed rods of iron erected on high buildings, &c. it may be agree- able to the curious to be informed, that the same experiment has succeeded in Philadelphia, though made in a different and more easy manner, which any one may try, as follows: Make a small cross, of two light strips of cedar ; the arms so long, as to reach to the 4 comers of a large thin silk hankerchief, when extended: tie the corners of the handkerchief to the extremities of the cross: so you have the body of a kite; which being properly accommodated with a tail, loop, and string, will rise in the air like those made of paper; but this, being of silk, is fitter to bear the wet and wind of a thunder-gust without tearing. To the top of the upright stick of the cross is to be fixed a very sharp-pointed wire, rising a foot or more above the wood. To the end of the twine, next the hand, is to be tied a silk ribband; and where the twine and silk join, a key may be fastened. The kite is to be raised, when a thunder gust appears to be coming on, and the person who holds the string must stand within a door, or window, or under some cover, so that the silk ribband may not be wet; and care must be taken, that the twine does not touch the frame of the door or window. As soon as any of the thunder clouds come over the kite, the pointed wire will draw the electric fire from them; and the kite, with all the twine, will be electrified; and the loose filaments of the twine will stand out every way, and be attracted by an approaching finger. When the rain has wet the kite and twine, so that it can conduct the electric fire freely, you will find it stream out plentifully from the key on the approach of your knuckle. At this key the phial may be charged; and from electric fire thus obtained spirits may be kindled, and all the other electrical experiments be performed, which are usually done by the help of a rubbed glass globe or tube, and thus the sameness of the electric matter with that of lightning completely demonstrated. 302 PHILOSOPHICAL TRANSACTIONS. [aNNO 1752. XCFI. A Letter from Mr. W. Watson, F. R. S. to the Royal Society, con- cerning the Electrical Experiments in England on Thunder Clouds. Dattd Dec. 20, J 752. p. 567. After the communications received from several correspondents in different parts of the continent, acquainting us with the success of their experiments last summer, in endeavouring to extract the electricity from the atmosphere during a thunder storm, in consequence of Mr. Franklin's hypothesis, it may be thought extraordinary that no accounts have been yet laid before the Society of our suc- cess here from the same experiments. That no want of attention therefore may be attributed to those here; who have been hitherto conversant in these inquiries, he states, that though several members of the Royal Society, as well as himself, did, on the first advices from France, prepare and set up the necessary apparatus for this purpose, they were defeated in their expectations, by the uncommon coolness and dampness of the air here, during the whole summer. They had at London only one thunder storm; viz. on July 20; and then the thunder was accompanied with rain; so that, by wetting the apparatus, the electricity was dissipated too soon to be perceived on touching those parts of the apparatus which served to conduct it. This in general prevented verifying Mr. Franklin's hypothesis; but Mr. Canton was more fortunate, as appears by the following letter from him to Mr. Watson, dated from Spital-square, July 21, 1752. " I had yesterday, about 5 in the afternoon, an opportunity of trying Mr. Franklin's experiment of extracting the electrical fire from the clouds; and suc- ceeded by means of a tin tube, between 3 and 4 feet in length, fixed to the top of a glass one, of about 18 inches. To the upper end of the tin tube, which was not so high as a stack of chimnies on the same house, I fastened 3 needles with some wire; and to the lower end was soldered a tin cover to keep the rain from the glass tube, which was set upright in a block of wood. I attended this apparatus as soon after the thunder began as possible, but did not find it in the least electrified, till between the 3d and 4th clap; when applying my knuckle to the edge of the cover, I felt and heard an electrical spark; and approaching it a 2d time, I received the spark at the distance of about half an inch, and saw it distinctly. This I repeated 4 or 5 times in the space of a minute; but the sparks grew weaker and weaker ; and in less than 2 minutes the tin tube did not a[)pear to be electrified at all. The rain continued during the thunder, but was consi- derably abated at the time of making the experiment." Mr. Wilson likewise of the Society, to whom we are much obliged for the trouble he has taken in these pursuits, had an opportunity of verifying Mr. Franklin's hypothesis. He informed Mr. W, by a letter from near Chelmsford in, Essex, dated Aug. 12, 1752, that on tluit day about noon, he perceival se- VOL. XLVIII.] PHILOSOPHICAL TKANSACTIONS. 303 veral electrical snaps, during, or rather at the end of, a thunder storm, from no other apparatus than an iron curtain-rod, one end of which he put into the neck of a glass phial, and held this phial in his hand. To the other end of the iron he fastened 3 needles with some silk. This phial, supporting the rod, he held in one hand, and drew snaps from the rod with a finger of his other. This ex- periment was not made on any eminence, but in the garden of a gentleman, at whose house he then was. Dr. Bevis observed, at Mr. Cave's at St. John's gate, nearly the same pheno- mena as Mr. Canton. Trifling as the effects here mentiont^d are, when compared with those which we have received from Paris and Berlin, they are the only ones that the last summer here has produced; and as they were made by persons worthy of credit, they tend to establish the authenticity of those transmitted from our cor- respondents. XCVII. On the Success of Inoculation at Salisbury, By Mr. Brown, Apothe- cary there, p. 570. ^^^, j,^ . From the 13th of August to the beginning of February had been inoculated, in this city and neighbourhood, 422 persons. On 5 or 6 of these it had no effect, though on one the experiment was tried a second time. Of this whole number 4 died ; one of which was a patient of Mr. B.'s, who, he thinks, did not do justice to this method; for the day on which the operation was performed, the patient's blood had been heated violently by exercise, and suddenly chilled again, by putting on clean linen, just before the operation was performed; which he apprehends, was receiving the infection in an inflamed state of blood; but with this he was not the least acquainted, till about 6 hours before the pa- tient's death. END OF THE POKTY-SEVENTH VOLUME OP THE ORIGINAL. /. Of an extraordinary Stream of Wind, which shot through part of the Parishes of Termonomungan and Urney, in the County of Tyrone, on JVednesday, Oct. 11, 1752. Bij JVm. Henry, D.D., Rector of the Parish of Urney. p. 1. Vol. XLVlil. The air for the whole day was serene and calm ; sometimes a gentle breeze from the s.e. About 4 in the afternoon, the sky seemed to open; and there was a flash of lightning from the s.e. Half an hour after, thunder was heard 304 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753, as at a great distance, from the same point. About 5 the sky was a little over- cast with clouds, but the air continued in a dead calm. Suddenly a violent rushing noise was heard; the sky seemed to open, and emitted a flash of light- ning ; but no noise of thunder ; and a stream of wind instantly ensued, the vio- lence of which nothing could resist. This stream of wind, so far as can be traced by its effects, arose from a glin called AUgolan, and continued its course for 3 miles from s. e. to n. w. The violent current of it seemed to be confined to a space about l6 feet in breadth, and the whole body of the air in motion did not exceed 6o feet, as may be com- puted from some of the particulars which happened in the little village of Lisna- cloon in the parish of Termonomungan, and the edge of the parish of Urney. At the distance of a mile to the s. e. of this village, it cut a line through several clamps of turf, which were standing in a bog, and threw down all the clamps in this line. Thence it crossed the river Derge, in the same line, and dashed up the water with great noise and violence. Thence, in the same line, and at the space of half a mile, it took the village of Lisnacloon, carrying away fences, the roofs of houses, and the tops of stacks. It then burst with incredible vio- lence through a cow-house, and cut a passage of l6 feet quite through it, and carried some of the ribs of the house before it 400 yards into the field; the rest of the house was a little ruffled. A woman who was gone into the cow-house a minute before, was knocked down by one of the ribs falling. She declared that it was a dead calm the minute before; when, on a sudden, she saw a flash of lightning, and heard and felt the violent storm, but heard no thunder. A man being in the same field, but out of the line, in which the stream of wind passed, felt no wind, but heard a mighty rushing noise, and saw the timber, thatch, turf, and dust of the houses, fly by him, at the distance of 40 yards. He saw a flight of rooks dashed down in the same field. In this village are se- veral other inhabited houses, both on the north and south sides of the course of this stream, none of which were in the least ruflied. The air continued still among these houses ; and the inhabitants stood astonished, on seeing the sudden devastation so near them. After passing this village, the stream was continued in the same line, but with less violence, to a large hill in the parish of Urney, called Muckle, and on the north side of the hill, at the distance of a mile from Lisnacloon, burst open the door of a weaver, and broke down a web in his loom. As at this last place it entered a large bog, which is extended for 3 miles, it could be traced no farther. The time, in which this stream passed through the village of Lisnacloon, was about 5 minutes. It was succeeded immediately by a torrent of rain. VOL. XLTtll.] PHILOSOPHICAL TRANSACTION'S. 305 //. An Account of a Book, intitled, P. D. Pauli Frisii* Mediolanensis, &c. Disquisitio Mathematica in Causam Physicam Figurte et Magnitudinis Telluris Nostrce. Milan 1752. By Mr. J. Short, F. R. S. p. 5. It may be laid down as a rule in mixed mathematics, " That the determination of no physical quantity be carried further than the observations, or other mecha- nical measures, can bear;" lest there follow this incongruity, of the conclusion being more extensive than the premises. It would be absurd, for instance, in the resolution of a triangle, to compute an angle to the exactness of seconds, or a side to centesms of an inch, when perhaps the instruments used can mea- sure no angle less than 10 minutes, or a side only to the exactness of a foot. The conclusions of arithmetic and geometr}' are indeed rigorously true, but they are only hypothetical; and whenever the quantities, that enter any practical question, can only be measured within certain limits, it would be in vain to look for an answer perfectly accurate. The error of the instrument becomes itself one of the data, and we must content ourselves to find the limits which the quantity sought cannot well exceed, or fall short of, by such rules as Mr. Cotes has given in his excellent treatise on the subject. In like manner, when any physical theory is deduced from observations, its accuracy will still be in proportion to that of the observations on which it is founded. Sir Isaac Newton, in computing the ratio of the earth's axis to its equatorial diameter, confines himself to a reasonable approximation, and to 3 places of figures (229 to 230) ; because, whether that ratio is deduced from the difterent lengths of isochronous pendulums in different latitudes, or from the measurement of distant degrees of a meridian, or from both, the elements of the calculus can scarcely furnish a greater degree of exactness. And of the same judicious caution, we have many other examples in the works of that incompa- rable author. On the other hand, when observations and theories are brought together and compared, nothing can be justly inferred against a theory from its disagreement with the observations, unless that disagreement is greater than can be fairly imputed to the imperfection of instruments, and to the unavoidable mistakes of an observer; especially if the difference should be sometimes in excess, and at other times in defect ; or, as some of the observations should en- tirely vanish. Though these rules, manifestly well-founded, have been followed by all the best writers, our author observes, that several ingenious men, both in France and in Italy, have deviated from them, particularly in treating of the famous question concerning the figure o'f the earth. Some, with Messrs. Clairaut and Bouguer, attributing too much to the observations that have been made, and * Fail] Frisi was born at Milan about the year 1789. ' VOL. X. R R 306 PHILOSOPHICAL TBANSACTIONS. [aNNO 1753. taking them for absolutely exact, have concluded Sir Isaac Newton's reasonings on that subject to be faulty ; while Father Boscowich, a Jesuit at Rome, making them quite loose and uncertain, thinks no argument at all can be drawn from them, concerning the earth's figure : far less in confirmation of the Newtonian theory. In opposition to these two extremes, equally contrary to reason, as they are to each other, Frisi writes the treatise now before us; in the introduction to which he shows, 1 . That, though the ratio of the axis of the earth to its equa- torial diameter is, from M. de Maupertuis' operations in Lapland, and afterwards in France, that of 177 to 178; and by the theory only 229 to 230; yet the difference is no more, than what might arise from a mistake of about 60 toises in the measure of either of the two degrees, that are compared, or of 30 toises in each of them. Or, suppose the measure of the arcs to be exact, the same difference might be owing to an error of 4 or 5 seconds in the astronomical part. And such errors, or others equivalent to them, in a course of so many combined operations, our author considers as difficult to be avoided. But he adds, if the observations of M. de Maupertuis, and his fellow academicians, seem to differ from the theory, those of Messrs. Bouguer and de la Condamine exactly agree with it; according to whom, a degree at the equator, containing 56753 toises, and in latitude 49° 22' 57183 toises, the difference of the axis and equatorial diameter comes out to be -j-J-g • In answer to Boscowich, and those who make no account of the observations, our author allows, that if they were such as Cassini, and some other academicians, made in France, of the measure of a parallel of latitude, they could not be much depended on; that method being liable to several obvious inconveniencies. But he insists that, with the excellent instruments which were used, and considering the distinguished skill of the observers, as well at the polar circle as in France, and at the equator, the error on one degree of the meridian could not exceed 60 or 70 toises, which is a degree of exactness not only sufficient for the deter- mination of the first question, viz. whether the spheroid of the earth is fiat or long; but likewise to found an agreement between the observations and the theory, as near as can be expected or desired. The work itself is divided into 10 chapters: (1) De observationibus circa telluris figuram hactenus institutis. (2) De prin- cipiis et hypothesibus quibusdam. (3) De rotatione corporum, et vi centrifuga. (4) De mutationibus ex motu circulari ortis. (5) De attractione corporum ro- tundorum. (6) De comparatione gravitatis in variis homogeneae sphaeroidis locis. (7) De figura terrae. (8) De gradibus meridian] et parallelorum. (9) De loxo- dromiis nautarum, de parallaxi lunae, et aliis ex eadem theoria pendentibus. (10) De theoriag et observationum consensu. In chap. 1, we have a short history of the inquiries that have been made into VOT. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 30/ the magnitude and figure of the earth, down to the present times; and the pre- ference is justly given to the measurements of Mr. Lat. Toises Norwood in England, a. d. i635, and of the mem- O" O' 56753 bers of the French Academy of Sciences since that 45 0 57100 time. From these he gathers, that within less than 4Q 11 57183 60 or 70 toises, the lengths of a degree of the meri- 53 0 57300 dian are as annexed. &^ 20 57400 Chap. 1 contains an account of the principles on which this theory is founded, viz. the universal gravitation of matter, and the diurnal rotation of the earth. Our author mentions also the hypothesis of the earth's being originally in a fluid state; but rejects it as precarious and improbable. He allows however, that with regard to the present question, it is all one whether it was first a fluid or not, seeing the ocean is circumfused just in the same manner, and to the same alti- tude, as if the whole was still a fluid. Chap. 3 and 4 are employed in the doc- trine of centrifugal forces, and their effect in changing a fluid sphere into the form of an oblate spheroid. In the former of these chapters, the author resolves, as usual, the centrifugal force of a particle into two others; one, that acts directly contrary to the gravitation of the particle; and the other a force in a direction perpendicular to it. And this last he considers again as acting laterally on the contiguous particles impelling them towards the equator. But the quantity of this force, when greatest at the octant, he computes to be only j^^, ^.^ of the force of gravity; and therefore, says he, it may be safely neglected. In fact, after the spheroid is come to be in a permanent state, and all its parts in equili- brio, there is no longer any such- lateral force at all ; it being now entirely satis- fied by the gradual contraction of the earth's axis. The general contents of the following chapters are sufficiently expressed in their titles already given. Nor can we be more particular, without entering into a detail of algebraical operations, which would be improper for this place; and which is the less necessary, as the same things have been treated of by several other authors. This does not however in the least detract from the merit of Frisi, who discovers throughout this work much acuteness and skill, joined with all the candour and ingenuity that become a philosopher. And as he has not yet exceeded his 23d year, it may be expected, that the sciences will one day be greatly indebted to him ; especially as we find him actually engaged in composing a complete body of physico-mathematical learning. But there is in his 6th chapter, a criticism on one of Sir Isaac Newton's de- monstrations, in which we cannot agree with him. And as this demonstration has proved a stumbling-block, not only to Frisi, but to many other learned men, we shall be obliged to consider that part of it, which has been mistaken, at some length, by the help of the scheme, fig. 1, pi. 8. In which let the ellipsis a/>boa, rr2 308 PHILOSOPHICAL TRANSACTIONS. [aNNO 1733. whose axes ab, pq, are in any given ratio, as of m to n, have tlie circles apbq, and APBQ, inscribed and circumscribed to it: and if the figure. revolves on the axis PQ, there will be generated an oblate spheroid a/jb^a, with 1 spheres, the greater circumscribed to the spheroid, and touching it in its equator aba, and the lesser inscribed and touching it in the poles p, q ; the solid content of the spheroid being the first of the 2 mean proportionals between the solidity of the exterior sphere, and that of the interior. But if the figure revolve on the axis ab, there will be generated a prolate spheroid a/jb^a, inscribed in the exterior sphere at the poles a, b ; and circum- scribing the interior sphere at the equator pqp, its solidity being the second of the above mean proportionals. So that if o and p stand for the solidities of the oblate and prolate spheroids, and s, s. for tlie two spheres; s : o : p : s-r— are in the continued proportion of m : n. And s : 7, or o : s :: m^ : n'. As s : * :: m^ : n^. Or we may with Sir Isaac Newton consider the genesis of these solids as follows. 1. Let the sphere apbq be uniformly compressed in the direction of its axis PQ, till that axis is diminished to p^, and the sphere changed into the oblate spheroid. 2. Let this spheroid be equally compressed in the direction of that diameter of its equator, which is perpendicular to pq and ab, or to the plane of the figure; and it will degenerate into the prolate spheroid, whose poles are a and b. 3. Let this last be compressed in the direction of its axis ab, till it is changed into the sphere apbq; and, in each of these compressions, the solid space which the body contains, will be diminished in the ratio of m to 7^. Now, as the determination of the earth's figure depends not only on that of the ratio of the centrifugal force, by which a body tends to recede from the axis of rotation, to the power of gravity ; but also on the decrement of gravitation, arising from the body's being in that rotation actually removed to a greater dis- tance from the centre; it is not enough that we know, from the experiments with pendulums, the centrifugal force at the equator to be about ^4-g- of the force of gravity. We need fiirther two distinct propositions; one to determine the attractive force of a spheroid at its pole ; and the other to determine its at- traction at the equator. The first of these we have in Princip. lib. J, prop, gi, and the second has been supplied by several authors. But Sir Isaac, who seldom does any thing in vain, found that he could, by one of his artifices, make that gist proposition serve likewise to determine the attraction at the equator, by the following argument. Let G be the attraction of the exterior sphere at a; and let the decrement of that attraction, when the sphere is diminished into the oblate spheroid Apsq, be d; and S the decrement of this last attraction, when the oblate spheroid is dimi- nished into the prolate, whose poles are ab; then is d nearly equal to S; the difference of the axes of the generating ellipse being small. For the attractive VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. • 309 matter that is taken away, has, in both cases, the same ratio to the matter that is left; and its position, with respect to that which is left, is in both cases nearly the same ; and therefore the successive attractions will be nearly in continued proportion, g:g — d :g — d ~ S -^. Or multiplying and rejecting c/' as incon- siderable, Gd = G^, and d = S. Thus, if the attractions of the sphere Apsa, and of the prolate spheroid, at its pole A, be 126 and 125 respectively; the attraction of the intermediate oblate spheroid at its equator will be 125-1^: and how nearly this approaches to the truth, may be seen from an exact computation of those attractions. For if the axes of the generating ellipse be JOl and 100, and the attractive force at the surface of the sphere 12(3; the attraction at the pole of the prolate spheroid will be 1 24.9838^ and that at the equator of the oblate 125.5077; which exceeds the arithmetical mean between the two former, only by .0O68 ; that is, by about -rr-r-nr part of the attraction of the oblate spheroid at the equator. This reasoning is more shortly expressed in the Princip. lib. iii, prop, ig, as follows. " Gravitas in loco a in sphaeroidem, convolutione ellipseos ApBg circa axem ab descriptam, est ad gravitatem in eodem loco a in sphaeram centro c radio AC descriptam, ut 125 ad 126. Est autem gravitas in loco a in terrain media proportionalis inter gravitates in dictam sphaeroidem et sphaeram ; propterea quod sphaera, diminuendo diametrum pa in ratione 101 ad 100, vertitur in figuram terrae; et haec figura, diminuendo in eadem ratione diametrum tertiam, quae diametris ap, pa perpendicularis est, vertitur in dictam sphaeroidem ; et gravitas in A, in utroque casu, diminuitur in eadem ratione quam proxime." In which the expression " eadem ratione" occurring a second time has misled F. Frisi and others, to think, that this last ratio is also that of the axes, or of 101 to 100; wheyeas the identity of ratios here asserted, is to be referred only to the words " utroque casu;" the ratio itself being not that of the axes, or of mton; but the half of that ratio (whatever it is found to be by prop. Ql, lib. i) which the attraction of the sphere has to the polar attraction of the inscribed spheroid. This inadvertence, however, of his own, Frisi charges on Sir Isaac Newton ; and files it up, as the 6th of the errors, which he says have been discovered in the Principia. ..." Ita dum stabilitae in IQ lib. 3 proposition! terrestrium axium proportionis fulcimentum et patrocinium quaerimus, aliud in propositione eadem sophisma sese offert, quod eorum, quae in principiis mathematicis Newtoni nacta (i. e. detecta) sunt hactenus, sextum est, &c." But we may take it off the file again; and for the present leave the other 5, till they are considered of at more leisure. In his 10th and last chapter, our author sums up the evidence, and finds that all the good observations that have been made, as well by pendulums as by 310 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. actual mensuration, concur with the theory, in making the ratio of the earth's axis and equatorial diameter to be as 22g to 230. This is indeed a sufficient confirmation of the theory of gravitation : but it must be observed, that the co- incidence is not perhaps quite so perfect as Frisi imagines. That ratio corres- ponds well enough to the exactness to which the first elements of the calculus can be obtained ; the length of a second pendulum, and that of the earth's equatorial diameter, from which the centrifugal force (-g-^) is deduced. But, if we suppose that force to be accurately f-i- and compute more rigorously, we shall find the ratio in question to be very nearly that of 225 to 226 ; agreeing still with the observations as well as can be desired ; and showing, at the same time, the inimitable art of Sir Isaac Newton in the contrivance and use of ap- proximations ; seeing the strictest calculation raises the equator not the third part of a mean geographical mile above what he had found by his method. I sent, says Mr. Short, Frisi's book to my learned friend the Rev. Mr. Mur- dock, who has fully considered the question concerning the figure of the earth ; and who, after having perused the book, and discovered the above mistake of Frisi, sent me the above theorem, and its demonstration. He likewise sent me the following theorems, which, he says, he had communicated to M. de Bre- mond, in the year 1740, when he was translating his treatise on sailing : but M. de Bremond dying soon after, those who had the care of publishing the translation, printed it incorrectly in several places ; particularly the theorems for the prolate spheroid : on which account, he says, if they are thought worth preserving, they may be inserted in the Phil. Trans. Postscript. — Theorems for computing the ratio of the attractive force of a spheroid, at its pole or equator, to that of the inscribed sphere. 2. In a prolate spheriod, the ratio is, ?n Polel-;;^,— ^ +___^3X/:. m' 1 . In an oblate spheroid, the ratio is, 1 m^ Equator j^;^r—[)i X A - ^^— y : ^ Equa. ^tzTT " ^;;rr)i X ^ In which m : 1, as the greater axis of the generating ellipse is to the lesser, A is a circular arc, to the radius 1, whose tangent isV^m^— 1, or its reciprocal if ^2 _ 1 c- 1 . And / is the natural logarithm of -, s being the sine of the arc, whose co-sine is - X V'm^ — 1, and v the versed sine of the same arc. m Note, The first two theorems, by substituting l for '^ ni^ — 1, coincide with those of Mr. Maclaurin for the oblate spheroid, in his dissertation on the tides. HI. Concerning the Year of the Eclipse foretold by Thales. By the Rev. Mr. George Costard, Fellow of fVadham Coll. Oxford, p. 17. Riccioli supposes that the eclipse foretold by Thales happened the year a. c. 585 ; VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 311 and quotes both Theon and Cleomedes in confirmation of the opinion. Theon perhaps had Cleomedes's words in view; but neither of these authors have cir- cumstances enough to determine what eclipse in particular they meant. The passage of Theon is in his chapter concerning the moon's parallax, where he says that Hipparchus, being in doubt whether the sun had any parallax at all, supposed, in the first book of his treatise concerning magnitudes and distances, that the earth, in respect of the sun, was only a point ; whence, by means of an eclipse there set down by him, he framed two distances of the sun, a less and a greater. All then that is here said is, that the eclipse made use of by Hippar- chus, was at the Hellespont ; but at Alexandria in Egypt a little more than 5 digits only. But he has neither given the asra of Nabonassar, the place of the luminaries, nor any one circumstance besides, by which we might form any con- clusion what year this eclipse was in. Cleomedes, who perhaps saw the same treatise of Hipparchus, is as uncircum- stantial as Theon. He says only, that the diameter of the moon's shadow at the earth is something more than 4000 stadia. By the quantity of obscuration he mentions, this seems to have been the same eclipse with that quoted by Theon from Hipparchus ; but as the place of observation in both these authors appears to have been Alexandria in Egypt, it must have been after that place was built. Consequently it was probably observed there by Hipparchus himself, and there- fore could not have been the eclipse foretold by Thales. Besides, if this eclipse was total on the banks of the Hellespont, I know not what reason there is for supposing, that the battle between the Lydians and the Medes was fought there. It should rather seem, that the engagement was on the confines of the two king- doms : consequently in a more southern latitude, and in a longitude more to the east of Alexandria, this eclipse could not have been total ; nor therefore (as He- rodotus said it did) turn day into night. Sir Isaac Newton, in his chronology, likewise supposes the eclipse meant to have been that in May, a. c. 585. But in this perhaps he rather follows others, than adopted it after any examination of his own. That treatise never had the finishing hand of its great author, and it is well known now in what manner it came abroad. According to Riccioli, this eclipse was central at the Hellespont, and at Sardes fell out at 6 in the afternoon ; and therefore is rejected by Mayer, in the Peters- burg acts, as being too late in the day. According to my computation, the apparent time of the true conjunction was at Greenwich, May 28, 4^35"' 15^; the beginning of the general eclipse 2*^3"' 30'; the end of the same 7^ l"" 46\ And by calculating the path of the pe- numbra's centre over the earth's disk, it pretty plainly appears, that the centre of the shadow passed so far from any place, where we can reasonably suppose the 312 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. battle between the Lydians and Medes to have been fought, that this can hardly have been the eclipse mentioned by Herodotus. Father Hardouin, in his chronology of the Old Testament, rejects this eclipse, as not happening, he says, in the reign of Cyaxares, but in that of Astyages ; not on the 4th year of the Olympiad, but a month before it began ; as falling out too late in the day ; the greatest obscuration being scarcely half an hour be- fore sun-set; and not total or central, or 12° 56' digits, as Riccioli makes it, but almost Q. Though Pliny therefore says this eclipse was Olymp. xlviii, 4, and A. V. G. CLx, yet six mss. he observes, in the French king's library, have clxx, and so most printed copies. He thinks therefore, that instead of clxx, the num- ber should be clvii, which he says is Olympiad xlviii, 4, and the year before Christ 597 ; when there was an eclipse of the sun, on Wednesday July the Qth, at 6 o'clock in the morning. This eclipse Petavius also prefers ; though he makes the digits eclipsed only 9,22' : which is strange enough, as it could not have been lay any means the cause of such a darkness as is described by Herodotus. Bu,t F. Hardouin sup- poses, that this battle was fought on the banks of the river Halys in Cappadocia, and in latitude north 40" ; where, says he, this eclipse must have been central and annular. According to Dr. Halley's tables, the year before Christ 597, the apparent time of the true conjunction at Greenwich, was July 8'^ 21^ 50™ 9'; the be- ginning of the general eclipse 19'' 8™ l6% and the end 9'' o'' 49™ 2^ And from the course of the centre of the penumbra, it appears that this eclipse, at Sardes, or any where else where we can suppose this battle to have been fought, could not have been great enough to turn day into night ; and there- fore does not answer the description of Herodotus. Archbishop Usher rejects both these eclipses, as inconsistent with his chrono- logy ; and supposes that intended to have been a.m. 4113, An. Nab. 147, be- fore Christ 601, Olymp. xliv, 4. Sunday July 20 3*' 25™ before noon, digits eclipsed 9. But this also is greatly defective as to quantity. But though this is insufficient for the purpose, yet there was one 2 years before this, or the year before Christ 603, that will be found by good tables entirely satisfactory. Pe- tavius indeed makes the digits eclipsed only 7 -20'; but, according to Dr. Hal- ley's tables, the apparent time of the true conjunction was at Greenwich, May J yd 20^ 42™ l^'- The place of the luminaries V 19° 12', and the moon's lati- tude north 25' 17'. Beginning of the central eclipse. 19^ 13™ 27^ End of the central eclipse 22 3 47 And if modern maps and geographers may be depended on, the centre of the shadow passed over the kingdom of Barca and Africa, and crossed the Mediter- VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 313 ranean between Candia and Cyprus, and then over Antiochetta and Erzroum, and a little to the south of Kars. Which agrees with what is said in the Pe- tersburg Acts, [J. 332. If any allowance is to be made for the moon's accelera- tion, or any other cause, the track here given will be a little different. As Mr. C. cannot make several ancient eclipses, that he has tried, succeed to his mind, without some such supposition, he has done the same with regard to this, viz. 45"", at Mr. Whiston's rate of 1™ in 54 years, or thereabouts. Then agreeably to this he finds, that the centre passed more to the south than the former, and went near Tripoli, Aracta, Nisabin, and Ardbil. It is much to be wished, that Herodotus had told us where this battle was fought ; that by this means we might have known which of these 2 paths to have preferred. However, as he has not, and there is nothing in either of them that is inconsistent with the history, Mr. C. concludes, from a number of other circumstances besides, that this really was the eclipse foretold by Thales. He was not a little pleased on looking into his papers, to find that Bayer and he agi'eed so exactly in the very year, and he was a stranger to what he had said on that subject, till he saw his account in the volume of the Petersburg Acts. If^. The Case of Anne Elizabeth Queriot, of Farts, ivhose Bones were Distorted and Softened. By Ambrose Hosly, M. D. of Paris, p. lQ. Anne Elizabeth Queriot, aged 35, native of Paris, was nian-ied in the year 1746, was brought to bed in 1747, and for the first time complained of great weakness in the small of her back, loins, and thighs, and could scarcely walk. A 2d lying-in, a year after, removed her complaints for about 6 weeks ; after which they returned. In the year 1749, being 2-|- months with child, she was seized with a loss of blood, and miscarried. Two months after, she fell on her left side ; which gave her great pain in the leg, thigh, and hip of that side, and made them swell : but there was neither fracture nor dislocation. Her pains after some time abated ; but the weakness of her limbs continued. She was a 3d time with child, and, in the beginning of her pregnancy, had a 2d fall ; which revived her former pains, and caused new pains all over her body, with a swelling, as before. This confined her to her bed, yet her pregnancy terminated favourably, after which the swelling went off; but her limbs were so weak, that she could not bear upon her feet. In about 6 months after her last lying-in, her pains returned worse than be- fore ; and about the same time, an abundance of white chalky sediment appeared in her urine ; and the fore-finger of her right hand was observed to be distorted towards the little finger : which was the first appearance of the dissolution that ensued. Soon after the lower extremities began to turn upwards gradually, and almost in a parallel line with her body, and continuing, till in 9 months her VOL. X. S 8 314 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. lower limbs were turned upvvards. All the bones were affected, especially the thorax, which had lost its natural form and capacity, and she was altogether mi- serably distorted. This miserable state was attended with exquisite pains ; and, according to the seat of them, the patient used to say, ' Now such a part works.' Sometimes they abated, and then she felt so sore, as not to bear being touched : and during this ease from her pains, a quantity of the aforesaid sediment passed by urine, though little or none in her sufferings. It was quite cretaceous, and, reduced into a fine powder, fermented gently with acids. She could bear no covering, but a few napkins, both from inward heat, and to avoid loading her breast. Not- withstanding her preternatural posture, the evacuations by stool and urine vvere regularly and easily performed. Her flesh seemed dead and oedematous, the skin rough and scaly ; so that a mortification was often apprehended. She had a cough, a laborious respiration, and sometimes a spitting of blood, from the coarc- tation of her breast, all its bones plying inwardly. She was capable of no other motion than turning her head on both sides, stirring her left arm in the shoulder- joint only, and separating her fingers, but not bending them. She had her menses regularly, till about 3 months before her death. She generally had a low fever, inward heat, sweats, and restlessness. Her fever ran very high in August, attended with delirium, headach, raving, and subsultus tendinum. A little before her death, came on a deafness, a dimness of sight, a scalding of her eyes, and a constant dropping ; violent pains in her head ; in short, a great weakness m all the organs, which showed how much the head was then affected. The distortion of her limbs went on so fast in August and September, that almost every 3d day something new was observed ; especially the left foot, during that time, came down gradually near 18 inches from under her ear, where it lay before. It was also observed in August, that her neck grew visibly smaller, the thorax much narrower. And then the napkins, on which she spit, grew black in the washing, and stained as from the mercurial ointment, though Dr. Hosty could not suspect it, as he could not learn she had ever used any mercury. In a month after, he observed the same thing on all the linen, that touched her skin. He got a napkin rubbed with soap, then dried, and afterwards washed. This method had almost taken off the stains, as it does those from the mercurial oint- ment. Her linen stained all the washing, like linen impregnated with it. Those spots appeared on the linen a mixture of a cretaceous matter and grease. Since this remark was made, none of the white sediment was seen. This, and the apparent nature of the stains, made him believe that it was then dis- charged by spittle, and the pores of the skin, and mixed with oily particles of her fluids, which had acquired a quality analogous to that of mercury, of staining all linen. He was also apt to think, that this sediment was the earthy matter. YOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 315 that gives the bones their solidity and liardness, which had been dissolved by the same vitiated quality of the fluids, and evacuated by the emunctories already mentioned. After great sufferings, she died the Qth of November. Her body was opened in the presence of some of the most celebrated anatomists and academicians of Paris. The operation was begun on the left tibia, cutting on the fore part of it, from below the knee to its basis. It was wonderfully altered ; more or less soft in all its length ; in some points entirely dissolved, and its sides not thicker than the gristle of the ear. The spongy substance of its extremities supple, yielding to the least pressure. The reticular matter was quite destroyed. The perone was entirely dissolved in the middle, and only slight marks of its extremities re- mained. Instead of marrow, they found in all the bones a red thick matter, like coagulated blood mixed with grease. The rotula was entire, but very soft and spong)' ; the condyles of the femur the same. All the cartilages were found in their natural state. The head of the humerus was much diminished and flattened ; its middle part very small, pliable softened in all points, yet in some friable. The cubit and radius suffered the same alterations with the humerus. By stretching all her limbs they laid them straight ; but they soon after returned to their former curve. The phalanges of the fingers were not so much softened, but were easily cut, and bent like whale-bone. The femur, vvas rather a fleshy body than a bone ; its cavity was filled with a reddish suet, instead of marrow, which, accumulated in different points, bulged out the fleshy sides. The capa- city of the pelvis was much diminished; the bones, that compose it, were soft- ened, thickened, and contracted. The spine kept its natural form ; the vertebrae , soft and supple. The sternum, and all the cellular bones, seemed solid, but could bend, and were easily cut. The ribs, though softened, were still friable. Some of them, towards the sternum, were doubled over each other. The cla- vicles seemed almost cartilaginous. The shoulder-blades were much thicker than natural, less broad, and entirely disfigured. The 2 protuberances called acro- mion and coracoides almost joined. The skull-bones were easily cut in slices, and were twice as thick as in their natural state. Both plates were joined in one, and no traces at all of a diploe. Their substance abounded with an extremely diluted serum, easily squeezed out by a gentle pressure of the fingers. The su- tures almost obliterated : the bones of the basis and face shared in the calamity. The teeth hard as usual. The dura mater was incorporated with the bones. The brain not softer than ordinary : its right hemisphere was by one third larger than the left ; and hence, perhaps, the weakness of her left side, often manifested by pains, achs, defluxions, heaviness, falls on that side, and every illness which she had from her infancy, beginning in some part of it. When young, she fell ss 2 3l6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. on her head down '2 pair of stairs. The membranes, that separate the 2 hemi- spheres of the brain, were much thicker than commonly. In fine, all her bones were so soft, that the scalpel with very little force ran through the hardest of them : even the rocky apophysis of the ear-bone, so called from its excessive hardness. Nothing extraordinary was found in the viscera ; but their size diminished by the compression, and a universal cachexy. There could be no cause assigned of this woman's disorder, as she gave no signs plain enough to prove either a scurvy, pox, or king's-evil, either heredi- tary, or acquired ; her parents having lived healthy, the one to the age of 80, and her mother being then alive, aged 6o, and in good health. She had 3 children, who died of disorders common to their age. One, 4 years old, died of the measles. This, it is added, is a rare case, but there have been some similar cases, which are cited in the Abridgment of the Phil. Trans, in the remark upon the like case presented to the b. s. by Mr. Silvanus Bevan. This differs from the other ex- amples, by the sediment of the urine, the stain on her linen, the preternatural situation of her limbs. Something very singular was, that she did not blow her nose perhaps once a month, even in her health ; always slept with her mouth opened, and her tongue hanging out. The manner in which such dissolutions of bones are accounted for, in the above-mentioned remark, seems the most rational and satisfactory, that can be given. F. Of a Roman uiltar, with an Inscription on it, lately found at York, and communicated to the Society of Antiquaries by Air. Francis Drake, F. R. S. Also a Brief Explication of the Inscription by John fVard, LL.D., and F.P.R.S. p. 33. This altar was found, with other remains of antiquity, by some workmen, in opening a deep drain down the centre of a large street, called Micklegate, in the city of York. Its height with the pedestal, on which it stands, and which is made hollow to receive it, is 14^- inches. But the breadth varies in several parts of it, according to their different form. On the top is an apex, with a volute on each side, and on the front a pediment over the inscription. It is elegant for the workmanship, and well preserved. Mr. Drake has sent up a draught of it in its just proportion, with the inscription upon it ; as also an- other copy of the inscription, taken off from the stone, by pressing wet paper into the letters, and then delineating both them and the stops with a pencil. The inscription itself in words at length, as Dr. W. thinks it may be read, is as follows : Matribus Africis, Italicis, Germanicis, VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 317 Marcus Minucius ^nde. Jfi miles legionis sexl vulgare hirsutum of Caspar Bauhin and Tournefort; or, what we usually call cow-parsnep. According to Gmelin, the plant in question differs from that species frequently met with in the pastures of Germany and England, only in its being much larger. This difference of size the Russian kind con- stantly preserves, when planted in the botanic garden. What we generally meet with here in England seldom grows higher than 3 feet, whereas the Siberian plant is double that size. Our author has given us a very exact description of it. This plant, which has never yet been applied to any useful purpose in these parts of the world, is of very great importance to the Russians and people of Kamtschatka. They indeed apply it to very different uses; the former distil their brandy :}: from it; the latter dry it to eat in winter. Dodonaeus § relates, that the inhabitants of Poland and Lithuania make a kind of liquor, which the poor people use as beer, from the fermented leaves and seeds of the sphondylium. • Erythronium. Linnaei Hort. ClifF. p. 1 19. Flor. Sibiric. torn. i. p. 39. — Orig. + Heracleum foliolis pimiatifidis. Lin. Hort. ClifF. p. 103. Flor. Sibir. torn. i. p. 213. Sphon- dylium. Rivin. tab. iv. — Orig. J Spiritum ardentem. — Orig. § Dodon. Stirp. Histor. p. 304.— Orig. VOL. XLVIII.^ PHILOSOPHICAL TRANSACTIONS. 355 When Steller, whom Ginelin always mentions with esteem, was at Tobolski in the year 1738, he was intbrmed, that 2 years before they were afflicted there with pestilential carbuncles, which were so contagious as to seize those who approached the person affected. The disease first began in horses and oxen, and afterwards seized the human species. A red spot first was perceptible under the armpits, or in the thigh, attended with great itching; and in a few hours grew to a very large tumour, joined with a burning heat of the part affected; these symptoms were attended with a very acute fever, entire loss of strength, violent pains in the head, and redness of the eyes. An old country practitioner, famous in these parts for his judgment, cured persons labouring under this severe disease in a short time. He used first to the carbuncle the powder of an herb,* of which is given a complete history and figure in this work, made into a thin poultice with dregs -^ of beer; this poultice, gently warmed, was applied to the part af- fected, and the patient confined to his bed, who was at liberty to take whatever nourishment he liked, except milk, brandy, or the flesh of pikes. During this time the patient drank plentifully of a decoction of this herb, collected during the time of its flowering; though the powder, applied as above, was prepaied from the leaves, before the flower-stalk was produced. The carbuncle, fVom this treatment, generally broke in 24 hours, and the symptoms greatly abated. The wound was sprinkled with sal ammoniac, and healed in a short time. This disease affected the cattle in different manners; some suddenly set a running with all their swiftness possible, and continued to do so till they dropped down dead; in others, carbuncles arose, which were dressed by the practitioner before-mentioned with the poultice above-described, mixing a large quantity of the herb with their food: and by this method great numbers were cured. A plant so well recom- mended, and which will grow in our own country, deserves to be better krtown to us. Throughout the whole work the author has shown a complete knowledge of the botanic science, among the first professors of which he is deservedly placed. XXIl. On a Mistake of Professor Gmelin, concerning the Sphondylium f-^u/gare Hirsutum of Caspar Bauhin. By Mr. Philip Miller, F. R. H. p. 153. Mr. Miller here remarks that in the abstract of the Flora Sibirica, which Mr. Watson laid before the Royal Society, it was mentioned, that the inhabitants of • Centaorea squamis ovatis, foliis pinnatis, foliolis decurrentibus, linearibus, scrratis et iiitegrii.' Flor. Sibir. torn. ii. p. 89, tab. 41. y^ Cyanus floridus odoiatus Turcicus, seu orieiitalis major, flore luteo. Hort. Lugd. B.if. p. 211.--J Orig. f Faece cerevisiae; though I am inclined to think yeast is intended, which is usually written floi' cerevisiae, or fermentum cerevisiae. — Orig. 1 35(5 , PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. Siberia ate the stalks of the sphondylium hirsutum C. B. P. But Mr. Miller had great reason to believe that Gmelin mistook the species; for he describes that plant as growing upwards of 6 feet high ; whereas the common sort seldom rises much above half that height. Therefore probably the plant mentioned by Gmelin was that species, which Breyn mentions in his 2d Prodromus, under the title of sphondylium maximum Transilvanicum Ricini folio, the seeds of which Mr. Miller brought from Dr. Boerhaave's garden in the year J 727, where it was gi-owing near the common sort of Caspar Bauhin, and in the same soil and situa- tion was more than twice the height; and the same difference has continued in the growth of both these plants since, in the Chelsea garden; where the large sort constantly rises to a stem, at least a month sooner in the spring than the common sort, and the leaves are much larger, less divided, and not so hairy; so that there can be no doubt of their being distinct species. • The seeds of that species of Breyn Mr. M. had received from Siberia, by the title of sphondylium vulgare, and Dr. Boerhaave told him, he had received the seeds from Austria, Hungary, and Petersburg, by the same name ; so that it is certainly the common sort in those countries. And it is very usual to find many mistakes in the writers on botany ; which has happened from their suppos- ing that the plants, which have been mentioned as common in one country, were the same with those of the country where they inhabited. An instance of this was the parietaria minor ocymi folio. C. B. which is the only species found wild in England ; and so was by all the English botanists taken for the parietaria offi- cinarum et Dioscoridis C, B. which are distinct species. And many "other in- stances might be mentioned. XXIII. Of an Eclipse mentioned by Zenophon. By the Rev. G. Costard, p. 155. The doctrine of eclipses is of great use in history and chronology. The ear- liest account of any in the Greek history is that said to have been foretold by Thales to the lonians, which Mr. C. has already treated of. The next, gene- rally taken notice of by writers, is that in the first year of the Peloponnesian war mentioned by Thucydides. But there is another before, which Mr. C. thinks equally remarkable, deserving some further consideration. It is well known, that Herodotus and other writers make Cyrus to have de- posed Astyages. On the contrary, Zenophon says, that Astyages was succeeded by his son Cyaxares, who left the kingdom to Cyrus by will. The truth, Mr. C. thinks, is, that Cyrus did not depose Astyages, and therefore so far Zenophon is right ; but deposed Cyaxares, in which he was designedly wrong. That he knew the Persians forced the empire from the Medes, appears from some no very obscure hints even in the Cyropagdia itself. After some critical remarks on the situation of certain places mentioned by ancient geographers, and astrono- mical calculations of eclipses adapted to them, Mr. C. finds that the centre of TOL. XLVIII.] fKILOSOPHICAL TRANSACTIONS. 357 the shadow passed over Kerkisia, not improbably, the Carchemish of the prophet Jeremiah, and a little to the north of Bagdad. It is not improbable therefore that it crossed the Tigris not far from the place where, it seems by Xenophon's account, Larissa was situated, and where consequently it would cause such a darkness as might well be attended with the eftects he mentions. This eclipse is, Mr. C. thinks, no inconsiderable acquisition to history and chronology, and is at the same time a confirmation of the suspicion, that in these very anc;;ent ones, there is some allowance or other to be made for the in- fluence of some cause, whatever it may be, hitherto not fully determined. This must be left for future observations. In the mean time however it may be of service to the science of astronomy to examine all the past eclipses that can be come at, and compare them with circumstances in the best manner we are able. XXIV. A new Method of opening the Cornea, in order to Extract the Crystalline Humour. By Mr. Samuel Sharp,* F. R. S. Surgeon to Guy's Hospital, p. l6l. The operation of discharging the crystalline humour from the eye, for the cure of that species of blindness called a cataract, was a k'w years since invented by Mons. Daviel, who performed it on many jjatients with remarkable success. Supposing it therefore admitted, that the extraction of the crystalline humour has been found by experience to be a useful method of cure, Mr. S. here sub- mits to the Society a new manner of making the incision of the cornea, by which Mons. Daviel's operation may be very much shortened, the patient would suffer less pain, and every skilful operator be equal to the undertaking. Place the patient in the same situation as for couching, either opening the eyelids with your fore finger and thumb, or letting an assistant raise the upper eyelid, while you yourself keep down the under eyelid. Then, with a small knife, holding its edge downwards, make a puncture through the cornea near its circumference, into the anterior chamber of the eye, in such a direction, as to carry it horizontally, and opposite to the transverse diameter of the pupil ; after which you are to pass it towards the nose, through the cornea from within out- wards, as near to its circumference as in the first puncture. When you have made the second puncture, push the extremity of the blade one-seventh of an inch beyond the surface of the cornea, and immediately cut the cornea down- wards, drawing the knife towards you as you make the incision. After this, you press gently with your thumb against the inferior part of the globe of the eye, in order to expel the cataract, and the operation finishes, according to the dif- ferent circumstances, as in the manner proposed by Mons. Daviel. One extraordinary benefit seems to arise from the use of this single instrument, • Author of 2 publications much esteemed, viz. one On the Operations of Surgery 1743, aud another entitled Critical Inquiry into the present Slate of Surgery, 1750. . 358 FHILOSOPHICAL TRANSACTIONS. [anNO 1753. and perhaps from the shape of its blade, which increases in breadth all the way towards the handle ; for, by this means, the punctures are so exactly filled up by the blade, that very little of the aqueous humour is discharged before you begin to make the incision, and consequently during this time, the cornea preserves its convexity; whereas by using one instrument to puncture, and others to dilate, the cornea immediately becomes flaccid on the issue of the aqueous humour, and renders the operation tedious and embarrassing, as he himself had found by experience in one patient, on whom he had performed the incision of the cornea with a pair of scissars, as recommended by Mons. Daviel. XXV. Experiments on Fish and Flesh preserved in Lime-waler. By Francis Hume, M.D. p. l63. With a design to find out how long he could keep fish and flesh fit to eat in lime-water. Dr. H. put two haddocks, and a pound of beef, in different pots full of lime-water, and corked them well, setting them in a cellar 18 days. He then took out one of the fish; it was sweet, sound, and firm. He boiled one part of it, and he broiled the other; it eat well, and had not the least taste of lime-water; but was not quite so firm as a fresh fish. But when he opened the beef-jx)t, to his great surprise, it stunk abominably. He poured the lime-water from both pots, and put in fresh lime-water. This stood 4 weeks longer; the remaining fish was quite fresh, and a little swelled, but when boiled, it dissolved to a jelly. The flesh was very putrid. Thus lime-water appears to presei-ve fish, but not flesh. Dr. Alston's experiment was made with fish, and Dr. Pringle's with flesh; which made the former say, that lime-water withstood corruption strongly; and that the latter did it but weakly, if at all. Dr. H. afterwards repeated the experiment more fully, and with the same suc- cess. On the !26th of March, he put a haddock into a pot of common water. He did the same to a piece of beef: the water was changed every day. At the same time he put a haddock into a pot of lime-water, and did the same with a piece of beef; at the same time he hung a fish and a bit of flesh in the air. On the 2d of April the fish and flesh in the air were a little corrupted and dried; the flesh and fish in common water smelt strong; the fish in the lime-water was sweet, and the lime-water good, and are so at present, April 0; but the flesh smelt rather worse than that in common water changed every day, and the cor- ruption had quite overpowered the smell of the lime-water. XXVL A Letter from Mr. James Short, F. R. S. to the Earl of Macclesfield, P. R. S. concerning a Paper of the late Servington Savery, Esq. relating to his Invention of a New Micrometer. Dated May JO, 1753. p. l65. It is now above a year, Mr. Short says, since he received a letter from TOL. XLVIII.J PHILOSOPHICAL TRANSACTIONS. 35g the Rev. F. Pezenas, professor of hydrography to the French king at Marseilles, in which he informed him, that M. Bouguer had read, before the Royal Aca- demy of Sciences at Paris, in the year 1 748, a memoir, in which he describes an heliometcr; which is an instrument consisting of 2 objective glasses, for measuring the diameters of the planets. He said also, that this memoir was ac- tuall\ in the hands of M. de Fouchy, perpetual secretary of the Academy, or at the Ro) al Printing-house ; and that it was registered in the minutes of the Aca- demy for the year 1748. Immediately after reading this letter, Mr. S. recollected to have heard a paper on the same subject, from the late Servington Savery, of Exeter, Esq. read be- fore the Royal Society, about the year 1743. He therefore had recourse to the minute book, of the Society for that year, where he found the following minute, which he copied in the presence of Lord Charles Cavendish, then vice-president. " A paper communicated from Mr. Savery at Exon, containing a new method for measuring the difference between the apogeal and perigeal diameters of the sun was shown ; and thanks being ordered. Dr. Bradley was desir^ to oblige the Society with an account of its contents. — Oct. 27, 1743." On application to Dr. Bradley, he sent the original paper to Mr. Short; on the back of which was a memorandum in the hand-writing of the late president, Martin Folkes, Esq. as a further proof of its authenticity, which runs in these words, " Delivered to me by Mr. Graham, sealed up by the author, and then broke open in his presence 5 26th Oct. 1743. M. Folkes." Mr. Savery's original paper was as follows: A new Way of Measuring the Difference between the Apparent Diametei- of the Sun at the Times of the Earth's Perihelion and Aphelion, or when the Sun is nearer to or farther from the Earth, tvith a Micrometer placed in a Telescope Invented for that Purpose; though the Charge or Magnifying Power of the Telescope is so great, that the whole Suns Diameter does not appear in it at one Fiew. By Servington Savery, of Exeter, Esq. Read Oct. 27, 1743. p. 167. Though this may appear impossible, yet Mr. S. has contrived some dioptric telescopes, and a reflecting one; either of which, by representing the object double, will, if well made, answer the design. Fig. 1, pi. 10, represents the whole body of the sun, as it ap{)ears double, and magnified in the telescope. Let an be the diameter of the one, and rx of the other image of the sun in perig£BO; so shall nr be the distance between the two images at that time; which measured with the micrometer is equal to, sup- pose, 10 seconds. Let bm be the diameter of the one solar image, and sw of SflCH PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. the other, when in apogaeo; so shall ms be the then distance of the solar images, measuring with the micrometer, suppose, \' 10. The difference of these two observations, 1 minute, is the apparent diminution of the sun's diameter. The little circle, whose diameter is dt, is the whole area visible at once in the telescope, which is not a 3d part of the magnified diameter of the sun; but since both nr at one time, and ms at another time, are visible within the teles- cope's area, if good instruments are procured, Mr. S. sees no difficulty in per- forming what he has proposed above, more accurately than it has ever yet been done, except this one (which some time since Mr. Graham mentioned in a letter to him) viz. that of defining the sun's disk, truly; and Mr. S. thinks, to do that to good perfection, is beyond human art. A telescope for this use may be made to magnify the sun's diameter to any degree whatever, not exceeding such degree as will make any part of the line ms fall without the area of the telescope: and he thinks it will be very difficult to make one with a charge so great, as not to have more than a geometrical minute of the sun's apparent diameter visible at once. v Since the sun is an object so very remote, the pencil of rays flowing from the centre of its disk, and incident all over an object-lens, though it should be a foot broad, would not differ sensibly from a perfect cylinder within the distance of above 100 miles from its basis at the lens; though in reality the whole pencil is an acute cone, whose angle at the vertex is almost evanescent. Hence it fol- lows, that if the two poles of two equal object-glasses are placed at the distance, suppose, of a foot from each other, the two centres c, v, of the two solar images must, as to sense, remain always at that very same distance, viz. 1 foot from each other, though the sun should be placed 10 times as far off as it now is; but since the sun's greater distance would diminish the diameters of both of the solar images; mn, added to rs, must be the true difference of the apparent dia- meters of the images, and also of the sun, at different times. According to Mr. Azout, Harris's Lexic. Techn. vol. i, see sun, the apparent diameter of the sun never exceeds 32' 45 "; hence its radius never exceeds l6' 12" 30'"; the tangent of which is about 476328, to the radius 100,000,000. Then, as the said tangent : to the said radius :: so half an inch : to 104. 96 inches, and decimal parts. According to this, if the focal length of a lens be IO4.96 inches and parts, it cannot collect the sun's rays to a less focus at the time of his perigee, than 1 inch in diameter, or half an inch radius. In fig. 2, the whole circle represents a well centred object-lens, whose focal length is, as above calculated, 104. 96 inches and parts, or rather a little less, that the two images may be sure not to touch each other. Let the two dia- meters dm, qf, divide it into 4 quadrants, but the diameter qf must be occult, or delible. Let cw be half an inch, and cv equal to it. Through v, and also ▼OL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 301 through w, let a chord line be drawn parallel to the diameter dm, viz. bg, hp. Through the said chord lines bg and hp, and also through the diameter dm, divide the lens into 4 parts. Fig. 3, Let the straight edge of the frustum bvgq, in the preceding figure, be cemented fast to that of the similar frustum hwpf of the same lens, as they ap- pear in this fig. 3. Having then with barm fastened a white paper all over both sides of the lens, he made for trial (which he did, not only to secure the ce- mented joint from breaking, but to prevent the injury which the polish might receive in cutting and grinding the edges) he described a circle qmnf on the centre c. fit for the tube he had to put in it: and having made it round, and washed it clean, after the edges were ground true, that nothing sandy might hurt the polish, he soaked it in clean water, till he could easily take off the paper. This model, made of a spectacle glass about 1 2 or 1 3 inches focus, gave him encouragement to try the following one, which he thought better. Fig. 4, Mr. S. made his second model of the 2 middle frustums mcdhwp, mcdbvg, of the lens in fig. 2, by cementing their edges, hwp, bvg, together, as they are placed in the present fig. 4, so the pole c of each part must consequently be half an inch, supposing its focal length is about 104 inches, from the middle where c stood in fig. 2, viz. the pole of one frustum where v, and of the other where w now stands. He left open at each pole a semicircular aperture rwq, svt, about ^ of an inch diameter, and covered all the rest of the circle axlkzo, to which he had cut it fit for the tube. The focus of the lens he made it of, was about 3 feet. Note, The rays of red light in the two solar images will be next to each other in both these models, which, he thinks, will render the sun's disk more easy to be observed than the violet ones. This he mentions, because the glasses in these two sorts are somewhat prismatical, but mostly those of the first model, which could therefore bear no great charge. Also the frustum on the right hand of the first model renders the solar image at the focus on the left, and that on the left hand renders it on the right; but it is not so with the second model, or with the next contrivance, which is the best, if well made. Fig. 5, In this, the greatest difficulty consists in getting two well-centred ob- ject-glasses, whose focal lengths are equal; for it is necessary they should be so, because they are to be combined with the same convex eye- lens, common to them, at the same distance, ab is the diameter of a plain brass plate, which may be 2-i inches broad, or somewhat less; two short equal cylindric brass tubes mn, rs, must be fastened on it, with their centre pc, equidistant from the centre 1 of the plate, and distant 1 inch from each other in the diameter ab, as the figure shows. In the tubes must be put two equal object-glasses of the focal length of 104-rV inches, or rather somewhat less, as aforesaid. Through the VOL. X. 3 A a62 PHILOSOPHICAL TRANSACTIONS. [anNO 1753. plate there must he made, in the middle of each tube, a round aperture, viz. hg, \vx, whose diameters must be proportioned to the focal length of the eye-lens, and not exceed the third part of it, lest the object appear confused. And since it is scarcely possible to centre an object-lens to very good perfec- tion, those in the two cylinders, may happen to render the two solar images at too great a distance from, or too near to each other. But this fault, if not too great, may be remedied, by turning one or both of the lenses a little way round; and then their eccentric poles will by that means be brought nearer to, or farther from each other; and when they are oncp well placed, there should be a mark made in each lens, and its cylinder; that if it is taken out to be wiped, it may be put in again the same way. There should also be a different mark in one of the glasses, that each may know its own cylinder. They must both of them be very close all round to their respective cylinders; otherwise one lens may slide nearer to or farther from the other; which if it should in the least degree, be- tween the first and second observation, all the labour would be lost. Either of these three parts of double lenses may be combined with a convex eye-lens as usual, and have a micrometer placed at the common focus. Such a double lens, of either sort, may be proved whether it is well composed or not, without the trouble of combining it with its eye lens, bv holding it in the sun's rays, as one would a burning glass, and applying a piece of white paper ' at its focus, where, he apprehends, the two solar images will appear as distinct as when an eye-lens is applied, though not so large; and each of them 1 inch broad, if the focal length be as above, i. e. almost 104-,25^ inches. After the same manner may the double object-mirror of a reflecting telescope for this use be proved. In fig. 6, the circle bdhpmg is the circumference of a concave mirror made of black glass: it must be very thick, that it may not spring or bend with any thing that presses on it to keep it fast, for that may injure its concavity. The circle within it, on the same centre c, shows that its concavity must not be continued quite home to the very edge of the mirror, but the little space between the two circles must be ground very true on a plain. The pricked lines must not be drawn; they are only to indicate where the poles vw of the two frustums must be brought, after the mirror is diametrically bisected. 'Let the concave side be defended, by pasting a paper all over it, and then let it be divided with a saw in the diameter dcm ; taking care that the said diameter be in the middle of the kerf, which may be as broad as the space between the lines ao, eq. Let the asperities of the edges of both frustums be ground off, that they may be very straight after being sawed. Fig. 7j represents a thick round plate of brass, very plain, and equally thick all over, having lines drawn on it, as on fig. 2, also one line on each side of the VOL. XLVIII,] PHILOSOPHICAL TRANSACTIONS. 363 diameter dm, equidistant from, and parallel to it. The distance of these two lines ao, eq, from each other equal to the kerf of the saw, which divided the mirror. The diameter of this plate must be equal to that of the mirror before it was divided. On the under side of the plate must be two pins fastened t, t, their diameters equal to the kerf of the saw, that they may keep the two frustums of the mirror at the same distance from each other that they were before their division ; so shall their circular edges be extended as far as the circumference of the plate, and their straight edges touch the said pins in the lines ao, eq. The end of the tube must be turned on the inside exactly to fit the plate and mirror, that they may not slide any way, for that would spoil the observations. In the diameter of the plate rs, on the points v, w, distant half an inch from c, the centre of the plate, and a whole inch from each other, let a circle, for the aperture of each frustum, of a proper size, according to the intended charge of the telescope, be described, and cut out. Also in the said diameter, equidis- tant from the centre c, viz. at x and z, let there be a screw for each frustum, to elevate it a little from the plate, as shall be needful. Let there be a spring contrived to press on the hack of the one frustum ora, against the point v, being the middle between the edge ao, and the screw x, to keep the frustum close to the plate at the points a, o, and also close to the screw x, when it is screwed in. Let the like be also done on the back of the other frustum esq. Then, 1 , before the two screws are put in at x, z, the two frustums of the mirror will lie plain on the plate of brass, and have one pole at c common to them, and consequently will collect all rays which, during their incidence, are parallel to the axis of the tube, to one common focus in the said axis of the tube, just as they would have done before the mirror was divided. 2. But when the two screws xz are put in their places, and screwed a little way through the brass plate, they will lift the two frustums free from the plate at their circular edges, viz. at r and s, while their straight edges ao, eq, are kept to touch the plate with both their ends (not in the middle, by reason of the mirror's concavity) by the pressure of the springs, as mentioned above. By this means the pole c of the frustum ora, will be removed from c towards r, and likewise the pole c of the other frustum esq be removed from c towards s, more or less according to the quantity of the elevation of each frustum, by the screw that raises it; so that now there will appear at the focus two solar images; whereas there was but one, before the screws were put in. By moving the screws, the two solar images may be brought to any distance from each other; but care must be taken not to raise one frustum more than the other, and the two solar images nuist almost touch one another at the time of the perigee ; otherwise it must be better adjusted. ., 3 A ii 364 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. This telescope may be finished with a small elliptical specillum of black glass, ground plain on its reflecting surface, and a convex eye-lens, like that described by J. Hadley, Esq. p. r. s. in Phil. Trans. N° 376. A micrometer may be con- trived for it at the common focus, near the eye-lens. Such a double-object speculum would be capable of a vast improvement, by combining it with a concave specillum, ^vhich would reflect the images through a hole in the centre c of the said speculum to fall on a convex eye-lens, after the manner of our new sort of reflecting telescopes, were it not for the difficulty of adapting such a micrometer to it as would exactly measure minutes and seconds ; for the eye-glasses of such having usually a pretty large focal length, would bear much larger divisions on a micrometer, than Mr. Hadley's with a small eye- glass can do, though their charges should be equal, or that of the former did exceed. Finding that large object-glasses for telescopes are not commonly well cen- tered, with their poles in the very middle of them, gives the following a rule for centering optic-glasses ; which may be very ready for a glass-grinder's use, and soon try whether a convex lens is well centered. Fig. 8, represents a round plate of brass, conveniently thick, and well har- dened by hammering, having many notches round it, one a little wider than that which is next to it, and numbered 1, 2, 3, &c. in their proper order, each of them wider at the bottom than at the entrance. He fitted such a notch to the thickest side of one of the glasses he had received from London, so as the edge entered it but a little way, not half its depth ; but, on trying the opposite side, it went in, the whole depth, and would have gone deeper, if the notch had been so cut : he then ground the lens narrower on that side which was thinnest, till he found it was at that place as thick as where he first tried it in the notch. After this manner he reduced the glass to an equal thickness on its 4 quarters, and then ground off from other places what was needful to bring it circular. He also took care, when he tried it in the notch, that the lens should not be warmer on the one side than on the other by grinding, but stopped till it was thoroughly cold ; and was also careful not to thrust it in harder on the one side than on the opposite side ; for he could plainly observe a diflerence after- ward, if he neglected to mind both these circumstances, or indeed either of them.* XXVII. Of a Contrivance for Measuring Small Angles. By Mr. John Dol- lond. p. 178. Let an object-glass, of any convenient focal length (being truly ground and * Dr. Smith, in his Complete System of Optics, published in 1738, has described a very accurate and ready method of centering object-glasses, which was always used by the late Mr. George Graham, from whom the Doctor had it. — Orig. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 365 well centered) be divided into 2 equal parts or segments, by cutting it straight through the centre ; and let a piece of machinery be so contrived, as to hold these two segments in the same position to each other, as they stood in before they were cut asunder ; and to be capable at the same time of drawing them to different distances from that position, in the manner as represented in fig. 7, pi. 8. Each of those segments will form a distinct image of any object, to which they are directed ; differing in nothing from that which might have been made by the whole glass before it was cut, except in brightness. And while these segments are held in their original position, the images will coincide, and be- come one single image as at first ; but in proportion as they are drawn off from that situation, the images will separate more or less, according to the distance they are drawn to. By this means the images of two different objects, or of different parts of the same object, not very far from each other, may be brought to a contact or coincidence at the focus : and this coincidence may be viewed to a very great nicety with a proper eye-glass. The measure of the angle subtended by the two objects, whose images are thus brought to a coincidence, depends on 3 things; 1st, a careful observation of the coincidence of the images : 2dly, an exact measure of the distance, which the glasses are drawn out to, from that situation which makes the image single : and lastly, a true knowledge of the focal distance of the glass. How the angle is to be found from these measures, and how it may likewise be come at, by view- ing two land-objects at a convenient distance, will be shown hereafter in the ex- planation of the figure. It is easy to understand, in the mean time, that the angle will be measured with more accuracy, in proportion to the length of the glass which is used for that purpose ; but the difficulty of managing long teles- copes is no less apparent. Therefore the most practicable method of using this micrometer to advantage, is to apply the divided object-glass to the object-encj of a reflecting telescope : for, as the apertures of this sort of telescopes are large in proportion to their lengths, they will admit of very long glasses ; nor will the measures be any way afiected by the metals or glasses, which the reflector is composed of: and the angles will be found in the same manner, as though the images were viewed with a single eye-glass, in the manner of a common re- fracting astronomical telescope ; but with this advantage, that as the images will be exhibited larger and distincter by the reflecting telescope ; and as every part of it will be much more manageable than a long refracting telescope ; so the contact or coincidence of the images will be more accurately observed. Explanation of the Figure. The two semicircles represent the two segments of the object-glass, whose 366 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. centres c and d are drawn off to the distance c d, and the points a and b are two objects, or different parts of the same object ; therefore the lines a c g and b d g represent two rays that pass through the centres or poles of the segments, and are therefore not at all refracted, but go straight through to g, where they in- tersect ; and g being the respective focus to the distance of the objects from the glass, the two images will coincide at that point. It appears from the figure, that ab: cd:: gh: ge; and from a common proportion in optics, g h : g e : : he: e f. Therefore ab: Cd:: he: ef; f being the focus of parallel rays ; and consequently the angles a e b and c f d are equal. That is, the angle sub- tended by the distance of the centres of the segments from the distance of the focus of parallel rays, is equal to the angle subtended by the distance between the objects a and b from the end of the telescope. XXVIIl. On the Copper Springs in IVichlow in Ireland. By John Bond, M. Z). p. 181. A spring of water flows from a rich copper mine, and is of a sharp acid taste, and light-blue colour. It is received and collected in pits, where iron bars are placed, which, after lying in the water about 3 months, are entirely consumed, and at the bottom of the pits, a quantity of copper, greater than that of the iron is found, in the form of coarse sand. This fact is confirmed by profitable expe- riments, often repeated since the discovery, the honour of which is due to Mr. Matthew Johnston, a worthy old gentleman, and one of the proprietors of the mine, who first proposed this method of collecting the copper. Experiment 1. Into some of this water, taken out of the stream above the pits where the iron bars are placed, he poured a solution of an alkaline salt, which raised a strong effervescence, and precipitated a large quantity of a dark- brown substance. Which showed that the water contained a strong acid, with a solution of the substance precipitated. Exp. 1. He put some aqua-fortis, or spirit of nitre, into water taken out of the same place ; and observed, that the strong acid immediately destroyed the blue colour. Whence he concluded that the substance, which was precipitated by the alkali in the first experiment, was so perfectly dissolved by the acid spirit in the 2d, as to transmit all the rays of light. Exp. 3. Some small iron nails put into this water, were in 4 minutes so closely covered with some substance of a copper colour, that, with a magnifier of \ inch focus, he could not discern the iron through it. In that time the nails gained 4 grs. The water had the same effect on silver and tin, but not on gold. The colour and increase of weight were owing to the adhesion of the particles of the matter dissolved in the \\ater by an acid, that could not pene- trate gold. VOL. XLVUI.] PHILOSOPHICAL TRANSACTIONS. 36; Exp. 4. In order to determine the quantity and quality of the matter in the water, he put 2 drs. of small iron nails into 3 oz. of it, and let them stand 24 hours ; then examined, and found the surface of the water covered with a thick scum, like that of a chalybeate spa. It lost the blue colour, and sharp vi- triolic taste. It was quite transparent, and at the bottom there was a quantity of a brown ponderous powder, whif;h, when dried, weighed 14 grs. This pow- der melted without any flux, produced 1 2 grs. of pure copper. The nails lost 8 grs. in the water, and were, in several places, covered with a solid lamina of pure copper. The water, in which the nails lay, after being filtrated and evapo- rated, afforded a green vitriol, which in every respect resembled sal martis, and produced the same effects, when dissolved, and mixed with any astringent tincture. Exp. 5. From the spring water treated in the same manner, he obtained a blue vitriol, the basis of which is copper. From all these experiments he infers, that a mineral acid is the active quality in this water ; which being diffused through the copper ore, unites itself with that metal, and forms a vitriol, which is dissolved by the water, and remains suspended in it, till it meets with iron in the pits, by which this acid is more strongly attracted than by the copper, therefore it quits the copper, corrodes the iron, and changes it into a vitriol, which is again dissolved, and carried off in the stream continually flowing from the pits ; while the copper, deserted by the acid, falls, by its specific gravity, to the bottom of the pits. By this account it is evident, that this admirable process is a simple precipi- tation of the copper, by means of the iron. Hence it has been improperly called a transmutation of iron into copper. But, lest any difficulty should still remain, concerning the consumption of the large quantities of iron put into the pits, he adds the following observations, to show that it is dissolved and carried off in the water. Observation 1 . The water in the pits are covered with a thick scum, occa- sioned by the air bubbles constantly rising, and bursting on the surface ; which is an evident sign of the solution of the iron. — Obs. 2. The iron is gradually consumed in the pits, and abounds with irregular depressions, like old iron : a strong symptom of its being corroded by an acid. — Obs. 3. The channel of the stream running from the pits is furred with red ochre, which, after being roasted in a strong fire, was attracted by the magnet. As this ochre is only found in the stream below the pits, it appears to be part of the iron dissolved in the water. — Obs. 4. The quantity of copper found in the pits, after the iron dis- appears, is generally greater than that of the ii*on when first put in : for the proprietors assured him, that sometimes a ton of iron will produce, or rather precipitate, a ton and half of copper. This fact alone would be sufficient to 368 PHILOSOPHICAL TRANSACTIONS, [aNNO 1753. prove, that the iron is not converted into copper ; since, according to Sir Isaac Newton's table, the specific gravity of copper is to that of iron as 9000 to 7645. When he was at this spring in August last, it ran at the rate of 12 oz. every second ; and by putting iron into the water of the stream running from the pits, he found, that every ounce contained 3 grs. of copper. Hence by calculation it appears, that 129600 grains of copper are carried off every minute, and conse- quently 1241001b. Troy weight in a year; supposing the quantity and quality of the water to continue the same. Hence we may easily account for the death of the fish, and other phenomena in the river, which receives this vitriolic stream. In a hot sunny day, when the water is exhaled, the heaps of mould, raised out of the ore-pits, are covered with a vitriolic efflorescence : hence, in rainy weather, the water appears like a strong solution of verdigrise. Whoever is desirous to imitate the process carried on in these pits, may readily gratify his curiosity, by putting pieces of iron into strong solution of vitriol. It is a common experiment, to tinge polished iron by rubbing it with Roman vitriol ; which depends on the cause before-mentioned ; viz. the acid in the vitriol penetrates the iron, and leaves the copper on the surface. This experiment is also taken notice of by that excellent chemist, and celebrated philosopher, Mr. Boyle, who calls it a sympathetic precipitation, in his Essay on specific Medicines. As soon as the attraction between the copper and the acid ceases, the mutual attraction between the minute particles of the metal prevails, so as to form large solid masses at the bottom of the pits, -^ of which are pure copper. These so- lid masses are partly occasioned by the pressure of the incumbent heap of granu- lated copper, constantly increasing. Hence we see, that the art of essaying, or separating metals from their ores, chiefly consists in evaporating an acid, which prevents the mutual attraction of the metallic particles : for when the acid is driven off by the violence of fire, the particles fall into their proper sphere of attraction, and assume a solid form. From what has been offered on the theory of this admirable process, several practical hints may be taken to render such springs more profitable ; and perhaps an easier method may be discovered of se- parating copper from its ore, by precipitation, than by calcination. This spring perhaps is as remarkable for its medicinal as its metallic qualities. Though physicians generally reckon copper, taken internally, poisonous, yet the miners and other people drink this .water frequently, without any ill conse- quences. It purges and vomits severely, and is become their specific in several diseases, particularly in cutaneous eruptions, arising either from an alkaline acrimony in the blood, which stimulates the sensible extremities of the cuta- neous arteries, and occasions a pustule, or from the irritation of insects lodged VOL. XLVIII.] PHItOSOl'HICAL TRANSACTIONS. SSQ in the skin ; both which causes may be removed by the strong acid in this water. It is an excellent detergent for scorbutic ulcers, as Hoffman justly observes. It has already performed several remarkable cures of this kind. Dr. B. had often recommended it in such cases with success, joined with proper internal medi- cines. How far the success of practice in the miners, who drink it frequently, might be depended on, longer experience must determine. Certainly, a great allowance must be made for the strength of their constitutions, and the insensi- bility of their nerves, constantly exposed to the noxious steams of damp pits. He never ventared to prescribe it internally : and as the materia medica affords vomits and purges of a more innocent kind, he thought it in that respect unne- cessary. He had reason to imagine, from the effects which this water had on some earth-worms, that it was a very powerful anthelminthic, if cautiously given. Some fresh filings of iron, put in this water, soon precipitated all the copper, and made it a strong and agreeable chalybeate. Hence it might be used as a sub- stitute for spa-water, the virtue of which depends on the iron. Some prepared filings of iron remained 8 days in this water ; without producing the least alter- ation. Hence it appeared, that this medicine could have but a weak effect, if any at all, in absorbing acids in the first passages. XXIX. On Mr. Gascoigne's Invention of the Micrometer. By Doctor Bevi.1, p. igo. Though Mr. Townley, in his paper printed in the Philos. Trans. N" 25, p. 457, has sufficiently made it appear that the invention of the micrometer w Dr. Knight, in his treatise on attraction and repulsion, prop. 69, has con- sidered the propagation of light, as performed by vibrations in an elastic fluid, in the same manner as sound is produced by vibrations in the air : and he thinks that it is as easy to conceive how the velocities of the particles of light may be different, and yet take up equal times in propagating their motions from one to another through a given space, as to explain how sounds of different tones move with equal velocities. In accounting for both, he shows, that in a series of par- ticles, which mutually repel each other, the greater their velocity, the nearer they will approach each other, in communicating their motions from one to an- other ; and consequently each of them must move through a greater space in so doing : therefore the same time may be spent in propagating a successive motion through a series of particles, whose velocity is greater, if each particle has to move through a greater space, as is spent where the velocity of each particle is less but is continued through a less space. The dilemma, to which our author's reasoning seems to have reduced the doctrine of refrangibility, may therefore be considered as a probable argument for adopting this hypothesis of the propagation of light through an elastic medium. XXXIX. The Case 0/ the Operation for the Empyema, successfully perjormed by Joseph Warner, F. R. S., and Surgeon to Guys Hospital, p. 270. John Collier, aged 17, was admitted into Guy's Hospital on the 10th of May, 1753, on account of a complaint in his chest, which he had laboured under for VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 3Q5 3 or 4 weeks. His symptoms were a continual pain in his left side, a difficulty in breathing, and an inability of lying on his right side, or of sitting upright, without greatly increasing his complaints. His pulse was quick, and low ; he had a short cough, was a good deal emaciated, and appeared sallow in his com- plexion. On examination, Mr. W. perceived a small tumor, situated on the anterior part of the thorax obliquely, on the left side of the extremity of the sternum or breast-bone. There was not the least discoloration of the integuments. On pressing on the tumor, his pain and difficulty of breathing were increased, and there appeared something like a fluctuation under the fingers. He had n6ver any rigor, which is a symptom generally attending the formation of matter ; but from experience he had found, that the want of this symptom is no proof of the contrary. From the foregoing circumstances, and symptoms, he had no doubt of the propriety of the operation, which he performed in the following manner : The patient being properly situated and secured, he began with making an incision of about '2 inches long through the integuments, and tendinous expansion of the oblique muscles of the abdomen on the most prominent part of the tumor ; then he proceeded to make a 2d incision, of an equal length with the former, trans- versely through the upper part of the rectus muscle, which had a perfect healthy appearance, directing his knife forwards, between the cartilaginous portions of the 7th and 8th ribs, into the cavity of the thorax; on which a thick clotted matter, to the quantity of 23 oz. and upwards, was discharged. After the whole of the matter was discharged, he introduced the fore-finger of his right hand into the cavity, with which he evidently felt the lungs quite loose, and free from ad- hesion, the mediastinum, and superior part of the diaphragm ; which last had been pressed somewhat lower than its natural situation by the weight of the in- cumbent matter. Hence it undoubtedly appeared, that this great quantity of matter was contained in the cavity of the thorax. After the whole of the matter was discharged, he introduced a linen tent, pro- perly secured, into the cavity ; which was continued to be introduced every day for about 3 weeks; now and then, as occasion required, making use of the prepared sponge-tent. The discharge of matter was considerable for the first week ; then it began to decrease gradually till, at the end of 3 weeks, there was no discharge at all. From this time, superficial applications only were made use of. At the end of 5 weeks he was perfectly well, and soon recovered his former plumpness, and healthy appearance. He observes, that, about 2 years before, he received a violent blow on his left side by a fall ; for which he had little or no care taken of him. He had ever after this accident had some complaints in his side at times, but not constantly ; 3 £ 2 3y0 PHILOSOPHICAL TRANSACTIONS. [anNO 1753. nor have they ever been so bad, as to prevent his acting in his business as a sailor, till within a few weeks befoje he applied to Mr. W. XL. On Infinite Series and Logarithms. By Air. James Dodson. p. 273. The terms of one of the most simple series, for expressing the logarithm of a given number, is composed of the powers of the excess of that number above unity, divided by their respective indices; of which the 1st, Sd, 5th, &c. terms are affirmative, and the 2d, 4th, 6th, &c. terms are negative ; and the differ- ence between the sums of the affirmative and the negative terms, is the Neperian, hyperbolic, or as some call it, the natural logarithm of the given number. Now a mathematician, who understands the nature and management of series, (though wholly ignorant of fluxions, or what Dr. Halley, in his investigation of this very series, published in N° 2l6 of the Philos. Trans, calls ratiunculae, &c.) might arrive at the same conclusion, in the following manner : Since the logarithm of 1 is universally determined to be nothing ; that of 2, 3, 4, 10, or any other number, considered as a root, is 1; that of 4, Q, l6, 100, &c. considered as the square of that root, is 2, and so on ; it follows, that in all cases the logarithm of a greater number will exceed that of its less; and each logarithm will have some relation to the excess of its number above unity, the number whose logarithm is nothing : the terms of the series therefore which will represent the logarithm of any number, will consist of the powers of the excess of that number, above 1, with some, yet unknown, but constant co- efficients. That the logarithm of the square of any number is twice the logarithm of its root, is a well-known property of those artificial numbers ; and therefore the doubles of the particular terms of the assumed series will constitute a series ex- pressing the logarithm of the square of the given number. But by prop. 4, book 2 of Euclid, the square of any quantity is equal the sum of the squares of its 2 parts, plus a double rectangle of those parts ; which, in this case (where the given number has been assumed to consist of I and an excess) will be l plus twice that excess, plus the square of it. If therefore the several powers of the compound quantity (twice the excess of the given number above 1 plus its square) be multiplied by the above assumed co efficients, and afterwards ranged under each other, according to the powers of the said excess, their sums will again express the logarithm of the square of the given number. Now since the logarithm of the square of the given number may be thus ex- pressed by 2 infinite series, each constituted of its excess above 1 , and its powers ; it follows, that the co-efficients of the like powers of that excess, in each series, will be equal between themselves ; and consequently the values of the unknown VOL. XLVIII,] PHILOSOPHICAL TRANSACTIONS. 397 co-efficients may be obtained, by simple equations ; and these co-efficients will, by the process annexed, appear to be the reciprocals of the several indexes of the powers of that excess, affected alternately with the signs -|- and — , as was before found, by the quadrature of the hyperbola, and by Dr. Halley in the above- cite30 6'. 343 Months, The Means. &c. Oct 3.049 Nov 2.229 Dec 3.684 Spring 8.<68 Summer . . 14.804 Autumn .. 16.913 Winter • •. . H.340 Total Depth 48.023 VOL XLVIII.] PHILOSOPHICAL TRANSACTIOKS. 401 inches, and the greatest part of that was the spray of the sea. And the mean quantity for each month of the aforesaid 13 years, is as in the margin annexed. XLII. On the Fossil found at Dudley in Staffordshire, and described in the Phil. Trans. N° 496. Bij Mr. Emanuel Mendez da Costa, F.R.S. p. 286. The famous fossil, which Dr. Lyttelton showed to the r. s. some time ago from Dudley, and which is described in N" 496 of the Trans, caused many arguments as to what class of animals it belonged-^ Dr. Pococke afterwards produced 2 or 3 specimens of it extended, which provdi it to be of the crustaceous tribe of ani- mals. But none of his specimens being very perfect, M. da Costa here sends a fair specimen of the said fossil extended, from the iron mines at Colnbrook-dale in Shropshire, and which determines him to pronounce it to be the remains of a crustaceous animal, of that kind called pediculi marini, which are scaled all round, and can at will roll themselves up : and this particular kind may be justly denominated pediculus marinus major trilobos. See fig. 8, pi. Q. Though he before thought it not described by any English author, yet he finds it described and figured, though badly, by Mr. Edw. Lhuyd, in his Lithophy- lacium Britannicum Ichnographicum, Epist. 1, p. 96, table 22 ; who found them in plenty in quarries, juxta aedes nob. v. D. Gryfidii Rice de Newton, arm. prope oppidum Sancti Teilavii, in comitatu Maridunias. He calls it buglossa curta strigosa. He also gives the figure of it without any description, in the Phil. Trans. N° 243. XLJIl. Letters relating to a Theorem of Mr. Euler, of the Royal yfcad. of Sci- ences at Berlin, and F. R. S. for Correcting the Aberrations in the Object- Glasses of Refracting Telescopes, p. 287. Letter L From Mr. James Short, F.R.S. to Peter Daval, Esq. F.R.S. Dated April Q, 1752. p. 287. There is published, in the Memoirs of the Royal Acad, at Berlin, for the year 1747, a theorem by Mr. Euler, in which he shows a method of making object- glasses of telescopes, in such a manner, as not to be aflTected by the aberrations arising from the different refrangibility of the rays of light ; these object-glasses consisting of tv/o meniscus lenses, with water between them. Mr. John Dollond, who is an excellent analyst and optician, has examined the said theorem, and has discovered a mistake in it, which arises by assuming an hypothesis contrary to the established principles of optics ; and in consequence of this Mr. Dollond has sent me the inclosed letter, which contains the disco- very of the said mistake, and a demonstration of it. In order to act in the most candid manner with Mr. Euler, I have proposed VOL. X. 3 F 402 FHILOSOPHICAL TRANSACTIONS. [aNNO 1753. to Mr. Dollond to write to him, showing him the mistake, and desiring to know his reasons for that hypothesis ; and therefore I desire, that this letter of Mr. Dollond's to me may be kept among the Society's papers, till Mr. Eiiler has had a sufficient time to answer Mr. Dollond's letter to him. Letter II. From Mr. John Dollond to James Short, A. M., F. R. S. concerning a Mistake in M, Eulers Theorejii for Correcting the Aberrations in the Object- glasses of Refracting Telescopes. Dated March \ I, 1752. p. 289. The famous experiments of the prism, first tried by Sir Isaac Newton, suffi- ciently convinced that great man, that the perfection of telescopes was impeded by the different refrangibility of the rays of light, and not by the spherical figure of the glasses, as the common notion had been till that time ; which put the philosopher on grinding concave metals, in order to come at that by reflexion, which he despaired of obtaining by refraction. For, that he was satisfied of the impossibility of correcting the aberration by a multiplicity of refractions, appears by his own words, in his treatise of Light and Colours, Book i. part 2, prop. 3. " I found moreover, that when light goes out of air through several contiguous mediums, as through water and glass, as often as by contrarj' refractions it is so corrected, that it emerges in lines parallel to those in which it was incident, con- tinues ever after to be white. But if the emergent rays be inclined to the inci- dent, the whiteness of the emerging light will by degrees, in passing on from the place of emergence, becomes tinged in its edges with colours." It is therefore somewhat strange, that any person should now attempt to do that, which so long ago has been demonstrated impossible. But, as so great a mathematician as Mr. Euler has lately published a theorem * for making object- glasses, that should be free from the aberration arising from the different refran- gibility of light, the subject deserves a particular consideration. I have there- fore carefully examined every step of his algebraic reasoning, which I have found strictly true in every part. But a certain hypothesis in p. 285 appears to be des- titute of support either from reason or experiment, though it be there laid down as the foundation of the whole fabric. This gentleman puts m : 1 for the ratio of refraction out of air into glass of the mean refrangible rays, and m : 1 for that of the least refrangible. Also for the ratio of refraction out of air into water of the mean refrangible rays he puts nil, and for the least refrangible n : 1 . As to the numbers, he makes m = 4-l, m = x^, and n = 4; which so far answer well enough to experiments. But the difficulty consists in finding the value of n in a true proportion to the rest. Here the author introduces the supposition above-mentioned ; which is, that • Vide Meraoires of the Royal Acad, of Berlin for the year 1747.— Orig. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 403 m is the same power of m, as m is of* n; and therefore puts n = m', and n — m'. Whereas, by all the experiments that have hitherto been made, the proportion will come out thus, m — \ : n — l::m — m:« — n. The letters fixed on by Mr. Euler, to represent the radii of the 4 refracting surfaces of his compound object-glass, are_/, g, h, k, and the distance of the object he expresses by a ; then will the focal distance be = — y — iYT — 7x — xTI — x\ — i — TTT Now, says he, it is evident, that the different refrangibility of the rays would make no alteration, either in the place of the image, or in its magnitude, if it were possible to determine the radii of the four surfaces, so as to have n (^ — i) + jw ( j- — ;^ -j- f — f ) = n (f — i) -|- m ( j- — ^ -}- X — i)- And this I shall readily grant. But when the surfaces are thus proportioned, the sum of the refractions will be = O; that is to say, the emer- gent rays will be parallel to the incident. For, if w (-^ — \) -\- m {f — 7 + i — i) = N (t - i) + M (^ - t + i - i), then ,2-N(t-i)+m-M(t-t + ■J- — i) = O. Also if ?i — N : m — M :: n — 1 : m—1, then n — 1 {f — i") + w— 1 (^ - t + i - i) = O; or otherwise „{f - i) + m {} - ^ + i - i) - ^ + ■J- = O; which reduces the denominator of the fraction expressing the focal dis- tance to X. Hence the focal distance will be = a ; or, in other words, the image will be the object itself. And as, in this case, there will be no refraction, it will be easy to conceive how there should be no aberration. And now Sir I think I have demonstrated, that Mr. Euler's theorem is entirely founded on a new law of refraction of his own ; but that, according to the laws discovered by experiment, the aberration arising from the different refrangibility of light at the object-glass, cannot be corrected by any number of refractions whatever. Lefter III.* From Mr. Euler to Mr. James Short, F.R.S. Dated Berlin, June 19, 1752. p. 292. MoNS. Vous m'avez fait un tres sensible plaisir, en ayant dispose M. Dollond de re- mettre la proposition de ses objections contre mes verres objectifs, jusqu' a ceque j'y aurois repondu, et je vous en suis infiniment oblige. Je prends done la li- berte de vous addresser ma reponse a lui, en vous priant, apr^s I'avoir dalgnee de votre examen, de la vouloir bien lui remettre : et en cas que vous jugiez cette matiere digne de I'attention de la Societe Royale, je vous prierois de lui commu- niquer les preuves detaillees de ma theorie, que j'ai exposee dans cette lettre. Cependant j'espere, que M. Dollond en sera satisfait, puisque je tombe d'accord * As these letiersr are on nice controveri>ial matters, it is considered safer and more satisfactory to gire them in their original language. 3 F 2 404 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. avee lui du peu de succes, qu'on sauroit se promettre de mes objectifs, en les travaillant selon la maniere ordinaire. Letter IF. From M. Euler to Mr. Dollond. Dated Berlin, June 15, 1752. p. 293. Etant tres sensible a I'honneur que vous me faites, au siijet des verres objectifs, que j'avois propose, j'ai celui de vous inarquer d'abord ingenumen, que j'ai ren- contre aussi ici les plus grands obstacles dans I'execution de ce dessein, vu qu'il s'agit de quatre faces, qui doivent etre travaillees exactement selon les proportions que j'avois trouvees: cependant ayant fait les experiences sur quelquesuns, qui parurent le mieux reussi, nous avons trouve, que rintervalle entre les deux foyers des rayons rouges et violets etoit beaucoup plus petit, qu'il ne seroit d'un verre simple de la meme distance focale. Neant-moins je dois avolier, qu'un tel verre, quand meme il bien seroit parfaitement execute sur mes principes, auroit d'autres defauts, qui le mettroient au dessous meme des verres ordinaires; c'est qu'un tel verre n'admet qu'un tres petite ouverture en consequence des grandes courbures, qu'on doit donner aux faces interieures: desorte que lorsqu'on donne une ouver- ture ordinaire, I'image devient tres confus. Ainsi puisque vous vous etes donne la peine, monsieur, d'executer de tels verres, en en faisant des experiences,* je vous prie de bien distinguer les defauts, qui peuvent naitre de la diverse refrangibilite des rayons, de ceux, qui viennent d'une trop grande ouverture : pour cet eftet vous n'aurez qu'a laisser une tres pe- tite ouverture. Or si ma theorie etoit juste, dont j'aurai bientot I'honneur de parler, il seroit moyen de remedier a ce defaut ; il faudroit renoncer a la figure spherique qu'on donne ordinairement aux faces des verres, et tacher de leur donner une autre figure, et j'ai remarque que la figure d'une parabole leur procureroit I'avantage, qu'ils admettroient une ouverture tres considerable. Notre savant M. Lieberkuhn s'est appliqu^ ^ travailler des verres dont la courbure des faces decroit depuis le milieu vers le bords, et il s'en est aperqu de tres grands avantages. Par ces rai- sons je crois, que ma theorie ne soufFre encore rien de ce cote. Pour la theorie, je conviens avec vous, monsieur, que posant la raport de re- fraction d'un milieu dans un autre quelconque pour les rayons moyens comme m ^ I, et pour les rayons rouges comme Mai, la raison de m — m a /« — l sera toujours si a peu pres constant, qu'elle satisfera a toutes les experiences, comme la grand Newton a remarque. Cette raison ne differe non plus de ma theorie que presque imperceptiblement; car puisque je soutiens que m = to , et que m * Mr. Dollond, in his letter to Mr. Euler, here referred to, does not say that he had made any trials himself, but only he had understood that such had been made by others, without success. — Orig. VOL. XLVIll.] PHILOSOPHICAL TRANSACTIONS. 405 diftere ordinairement fort pen de I'linite, soit m = 1 + «; et puisque m := wi''= 1 + a Im 'k peu pres, et / ( 1 + w) =. lm=. u, aussi fort a peu pres, j'aurai m - M = 1 + w - 1 - aw = (1 - a) w, et 7« - 1 =: w, donc la raison -^^^ — sera = l « ^ m — 1 ' oil fort a peu pres constante. Dela je concluds, que les experiences d'ou le grand Newton a tire son raport, ne sauroient eti-e contraires a ma theorie. En second lien, je conviens aussi que si la raison "' ~ = constant etoit m — 1 juste k la rigueur, il n'y auroit plus moyen de remedier au defaut qui resulte de la diverse refrangibilite des rayons, de quelque maniere qu'on disposeroit divers milieux transparens, et que I'intervalle entre les divers foyers tiendroit toujours un raport constant a la distance focale entiere du verre. Mais c'est precisement cette consideration, qui me fournit le plus fort argument: I'oeil me paroit une telle machine dioptrique parfaite, qui ne se ressent en aucune maniere de la diverse refrangibilite des rayons: quelque petite que soit sa distance focale, sa sensibilite est si grande, que les divers foyers, s'il y en avoit, ne manqueroient pas de troubler tres considerablcment la vision. Or il est bien certain, qu'un oeil bien constitue ne sent point I'effet de la diverse refrangibilite. La structure merveilleux de I'oeil, et les diverses humeurs, dont il est compose, me confirnie infiniment dans ce sentiment. Car s'il s'agissoit seulement de pro- duire une representation sur le fond de I'oeil, une seule humeur auroit ete suffi- sante; et le createur n'y auroit pas surement employe plusieurs. Dela je concluds, qu'il est possible d' aneantir I'effet de la diverse refrangibilite des rayons par une juste arrangement de plusieurs milieux transparens, donc puisque cela ne seroit pas possible, si la formule --^-^ = constant etoit vraye a la rigueur, j'en tire la conseqvience qu'elle n'est pas parfaitement conforme a la nature. Mais voila une preuve directe de ma these: je conqois divers milieux trans- parens, A, B, c, D, E, etc. qui different entr'eux egalement par raport a leur den- site optique : desorte que la raison de refraction de chacun dans le suivant soit le meme. Soit donc dans le passage du premier dans le second la raison de refrac- tion pour les rayons rouges = r : 1 , et pour les violets = v : \ ; qui sera la meme dans le passage du second dans le troisieme, de celuicy dans le quatrieme, du quatrieme dans le cinquieme, et ainsi de suite. Del^ il est clair, que dans le passage du premier dans le troisieme sera = /'- : 1 pour les rayons rouges, et = v^ : 1 pour les violets : de meme dans le passage du premier dans le quatrieme les raisons seront r^ : 1 et f^ : 1 . Donc si dans le passage dans un milieu quelconque la raison de refraction des rayons rouges est = r" : 1, celle des rayons violets sera = d" : ] ; tout cela est parfaitement confjnne aux principes du grand Newton. Posons r" = r, et ?;" = V, desorte que r : 1, et v : 1 expriment les raisons de refraction des rayons rouges et violets dans un passage quelconque: et ayant nlr = /r, et nlv = /v, nous 406 PHILOSOPHICAL TRANSACTIONS. [anNO J 753. /r Ir aurons Ir: Ir := l\ : Iv, ou -- = -. Ou bien mettes v = r~, et k cause de /v = »lr, on aura — = -, ou h = alR, et partant v = r . Voila done le fondement du principe, que j'ai employe dans ma piece, qui me paroit encore inebranlable; cependant j'en soumets la decision a 1' illustre Societe Royale, et 4 votre jugement en particulier, ayant I'honneur d'etre avec la plus parfaite consideration, Monsieur, &c. &c. XLIF. A remarkable Case of Fragility, Flexibilily, and Dissolution, of the Bones. By John Pringle, M.D., F. R.S. p. 297. Mary Hayes, of Stoke-Holy-Cross, near Norwich, gave the following account, June 21, 1752. That she was born Jan. ] 1, 17 18, and never married, nor was addicted to any kind of intemperance; that her father was unhealthy a great part of his life, but she knew not what disease he was subject to; that her mo- ther died when she was a child; but she did not remember having ever heard of her being unhealthy; that she herself was always considered as a healthy strong girl, till about 15 years of age; then fell jnto the green-sickness, and took va- rious medicines, to no purpose ; that this disease, as far as she could recollect, was all she had to complain of; doing the ordinary work in a farmer's house, till October 1748; she then was seized with pain universally, attended with feverish symptoms. Thus she continued some weeks; after which the pain was chiefly confined to her thighs and legs, but not increased by external pressure. In Sep- tember 1 749, she broke her leg, as she was walking from the bed to her chair, without falling down, and heard the bones snap. The fracture was properly treated, and regard had to her disposition; but no callus was generated, the bones growing flexible from the knee to the ancle in a few months, as did those of her other leg. Soon after, those of her thighs were visibly afl^ected in like manner. Both legs arid thighs then became very cedematous, and subject to excoriate, discharging a thin yellow ichor. The winter after breaking her leg, she had symptoms of the scurvy, and bled much at the gums. Many eminent physicians, who were of opinion that this disease of the bones might arise from acidity abounding in the blood, prescribed for her, but without efiect; unless the regularity of her menstruation for the last 18 jnonths may be attributed to a chalybeate medicine; though medicines of that nature had no such effect formerly, when she was in a condition to take exercise, and regularly persisted in the use of them. For some considerable time past she had found little alteration in her com- plaints in general; thought her appetite and digestion rather better, but that the difficulty of breathing, which she had long laboured under, gradually increased; and the thorax appeared so much straitened, as necessarily impeded the expan- VOL. XLVIII.] PHILOSOPHICAL TKANSACTION8. 407 sion of the lungs. Her spine became much distortetl; any motion of the ver- tebrae of her loins gave extreme pain; and her thighs and legs were become en- tirely useless; which wholly confined her to her bed, in a sitting posture: and the bones she rested on, having lost their solidity, were much spread. Also the ends of her fingers and thumbs, by frequent endeavours to lift herself up for ease, became very broad and flat. Then she measured but 4 feet; though, be- fore this disease came on her, she was about 5^ feet high, and well shaped. This is the best information that could be obtained from her own mouth, and what was observed in the case before, and at the first-mentioned time, when she readily consented to the examination of her body, &c. after death. From that time to her death, which happened Feb. 6, 1753, the chief thing she complained of, and what the people about her observed, was a gradual in- crease of difficulty of breathing; a wasting of her flesh; a cessation of her men- struation for the last 4 months; a tendency in her legs to mortify, which had long been anasarcous, and excoriated almost all over; she retaining her senses perfectly to the last moment of her life, and dying without showing the least signs of the agonies of death. Two days after death, her limbs being first well stretched out, she was exactly measured, and found wanting of her natural stature more than 2 feet 2 inches. Then the thorax and abdomen were opened, the sternum being entirely removed, with part of the ribs, in order to gain at once a full view of those cavities, and discover how the viscera there contained had obstructed each other in their re- spective functions. The heart and lungs were sound, but flaccid, and much confined in their motion; to which the enormous size of the liver contributed in some measure, extending quite across the abdomen, and bearing hard against the diaphragm. The lungs did not adhere to the pleura : nor was the liver scir- rhous, but faulty only in its bulk. The mesentery was sound, except only one large scirrhous gland on it. The spleen extremely small. Nothing else was found observable in those cavities. The skull was not opened, to examine the brain, as intended, through want of time, the minister waiting at church for interment, and the relations becom- ing impatient; but the operators had no reason to suspect any defect there, from any previous complaint. All her bones were more or less affected, and scarcely any would resist the knife; those of the head, thorax, spine, and pelvis, nearly to the same degree of softness; those of the lower extremities much more dissolved than those of the upper, or of any other part. They were cut quite through their whole length, without turning the edge of the knife, and much less resistance was found, than firm muscular flesh would have made; being changed into a kind of paren- 408 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. chymous substance, like soft dark coloured liver, only meeting here and there with bony laminae, thin as an egg-shell. Those bones were most dissolved which, in their natural state, were most compact, and contained most marrow in their cavities; and the heads of them were least dissolved. This perhaps is the more worthy observation, as it held good throughout, and looks as if the wonderful change they had undergone might be caused by the marrow having acquired a dissolving quality ; for it was evident that the dissolution began withinside, from the bony laminae remaining here and there on the outside, and no where else, and the pain not being in- creased at first by external pressure. The periosteum was thicker than ordinary: the cartilages rather thinner; but no where in a state of dissolution like the bones. The day after this examina- tion, some of the whole substance of the leg and thigh bones, that was entirely dissolved into a kind of pulp, was sent to an ingenious chemist; and, by the experiments which he made, he said he could discover neither acid nor alkali prevailing in it. XLV. Astronomical Observations made in Surry-street, London. By J. Bevis, M. D., and James Short, A. M, F. R. S. p. 301. Eclipse of Venus by the moon, apparent time, July 26, 1753. J gh 2"^ 1 7^ Venus totally hid by the moon. 17 5 6. . Her northern cusp emerged ; and, a few seconds after, her southern one. 5 31.. Venus was totally emerged. All these with a reflector of 2 feet focus. Then her diameter was found to be 324^*, with a new kind of micrometer; and also with one of Mr. Graham's sort, in a 2 feet Gregorian reflector. Eclipse of Mars by the moon, Aug. 20. 17 Q 49^ The moon's consequent limb passed the meridian. 8 4. . Mars's centre passed the meridian. His diameter then, with both micrometers, 13^. The moon's diameter 31' 21". 18 6 39t Mars totally hid by the moon with a reflector of 4 feet focus. Occultation of (3 Capricorni by the moon, Oct. 5. 7 16 50. .The moon's preceding limb passed the meridian. 20 4. . A small star, which preceded (3, passed the meridian. '20 1 9. (3 passed the meridian. Presently after, the moon's diameter ^sas found to be ig' 48", with the new micrometer, applied to a reflector of 2 feet focus. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. AOQ gh 2i"» 3' The small Star eclipseil by the moon. 28 48. . |3 eclipsed by the moon. g 48 24. . |3 emerged from the moon. Eclipse of the sun, Oct. 25. 20 30 10. .The eclipse had been some time begun; but, for clouds, could not be seen till now ; when the distance between the cusps, measured with the new micrometer, applied to a 2 feet reflector, was 12' 264-". 21 15 23. . The distance between the cusps 29' 49''. 18 6. . The distance between the visible limbs of the sun and moon 1 1' 32". 22 18 56. . The distance between the cusps 24' J 2-J-''- The day before, about 10 in the morning, the sun's horizontal diameter was 32' 17". These measures were all taken when the sun continued visible but for a few seconds, through the interstices of flying clouds; and yet from the nature of this micrometer, they may be very safely relied on : though it would have been im- possible to have catched any one of them vvith the common micrometer. The principle on which this most excellent instrument is constructed, was laid before this Society last May : and it is to be hoped that Mr. Dollond will evince the certainty of its measurements, from the least to the greatest angle it is capable of comprehending; and that, under every consideration of reflexion as well as refraction by spherical surfaces; so as to leave no room for such objections or cavils, as otherwise may probably be brought against it. For our own parts, we are fully satisfied of the justness of it, from a great variety of trials and compa- risons. That which we have hitherto used, is the first that has been made of the kind: and might perhaps have been better constructed in some respects, though in nothing material. Applied to a reflector of only 2 feet, the scale is as large as the common mi- crometer can have in a 40-foot refractor; and all is done without the help of screws or wires; so that there is no need of illuminating. In virtue of such a scale it is, that even fractions of seconds may be depended on : as we have found, by often repeated trials on the diameters of the planets. These, as well as small distances of stars, may be measured in all directions, with equal and almost incredible facility, without a polar axis; as well out of doors, in a rough wind, as within. XLVI. Concerning a Ciusttr- Polype,* found in the Sea near the Coast of Greenland. By Mr. John Ellis, p. 305. This marine production, sent him by Mr. Collinson, appears to be an animal, * Vorticella encrinus. Linn. Peiinatula encrinus. Linn. Gmel. VOL. X. 3 G 410 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. not a vegetable, being a species of cluster-polype, consisting of many bodies unitfed at one common base. This specimen appears to have 23 distinct ones; he saw another, tliat was taken at the same time, that had between 30 and 40. Each body is furnished at the top with 8 arms or tentacula, which expand them- selves in the fonn of a star. Each arm is again furnished on each side with a row of small fibres, which seem to do the office of fingers. In the centre of the 8 arms appears the mouth, surrounded by 6 little semicircular lips standing upright. On dissecting one of the bodies lengthwise, it appeared to consist of a strong muscle, contracted into little waves or wrinkles. In the little cavities of these are sundry small seed-like particles, perhaps the spawn of the animal: when magnified, they appeared of a spherical form, a little compressed. To the centre of the base, where the cluster of polypes unite, and make one body, there grows a four-square bony stem of 6 feet long, having 4 grooves, one on each side. At the joining to the fleshy part, the bony stem is very small, and a little twisted, like the turn of a screw, extending a membrane like a bladder, for about 2 or 3 inches in length, and nearly an inch in breadth, from the fleshy part downwards. The membrane then begins to close insensibly, and becomes a cuti- cular covering to the bony stem, which now increases gradually, till it becomes a quarter of an inch square. Within 5 or 6 inches of the bottom of the stem the bony part begins to grow smaller, till it comes to a point; and the cuticular part becomes cartilaginous, and supplies this tapering part with a quantity of this elastic substance, equal to the deficiency of the bone. The use of this mem- brane, or bladder-like skin at the top of the stem, may possibly be intended to give the animal a power to raise and fall itself in the water at pleasure. It ap- pears from the twist in one part of the stem, that the stem, when very small, and not so bony, had met with some violence, that had turned it out of its direc- tion; the mark of which has still grown on with it: for the stem of the other specimen, taken at the same time, was quite even. On cutting it across, they discovered the distinct laminae to each angle, rising from a small point in the centre, and separated by a cross, that joins the opposite grooves. On putting a thin shaving of it into vinegar, a strong eftervescence was immediately raised, which dissolved the gritty or coralline part, and disco- vered the fine membranes that enclosed it. These two substances seem to com- pose this bony, ivory, or coral-like stem. The disposition of the polypes, with regard to each other, is represented by a cross section in pi. Q, fig. f, where 10 occupy the outward circle, g are in the next, and 4 are in the centre. Mr. Ellis learned that it was taken in the latitude of 79° north; which is within 11° of the pole, and 80 English miles from the coast of Greenland, by VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 411 Captain Adriaanz, commander of the Britannia, wliile he was on the whale fishery last summer. The captain sounding one day in very deep water 236 fa- thom, 2 of them clung to his line. He says the arms or tentacula of the polypes were of a bright yellow colour, and fully extended, when he brought them to the surface of the water; and made a most agreeable figure, like a fine full-blown flower, which the captain took them for. Mr. Ellis further observes, that the encrinos, or the lilium lapideum of the curious in fossils, so little known before, is thought to be of this class. Rejtrenct's to the figures in pi. Q. — A, the clustered polype in its natural size, extending itself; b, the same polype, as it was received, after it had been soaked in water, and the tentacula laid straight; a, the polype in miniature, with its stem of bone or ivory ; c, part of the ivory stem twisted ; d, the lower part of the stem, covered with a cartilage ; e, the cartilage opened, to show the tapering of the bony part ; f, the cross section, to show the position of the several bodies of the polype; h, the cross section of the bony stem magnified; g, one of the bodies cut open, to show its internal muscular form; 1, the eggs or spawn in the natural size; l, the same magnified; i, the cuticular covering, which is con- tinued from the bladder at m to the cartilage at e, or from one end of the stem to the other; n, the indented muscular base, where the bodies of the polype all unite; k, a figure of the encrinos, or lilium lapideum, from Rosinus. XLFIL Extracts of two Letters from Father Gaubil, of the Society of Jesus, at ' Pekin in China, translated from the French. Dated Pekin, Nov. 2, 1732. p. 309. 1 . To the R. S. The Chinese, without being consummate, or even passable astronomers, might be capable of obseiTing an eclipse, and of making observations on it, and of looking on the shadow of the gnomon of a sun-dial. The knowledge, which they had from time immemorial of the rectangle triangle, and of its principal properties, might easily teach them a thousand curious things in geometry, with- out knowing the theory of trigonometry. The Chinese, from time immemorial, knew the passage of the sun in the ecliptic ; they knew the stars ; they had globes and hemispheres ; and, by means of divers practices and precepts, received from their ancients, without any great knowledge of spherical trigonometry, might be able on the globe itself to resolve many problems. We ought to conclude, that our ancients were possessed of several kinds of knowledge, received from the patriarchs, and transmitted to the Chinese. Without these kinds of knowledge, and these traditions, by mere ob- servations alone, the Chinese could not perform what they did at first. They never well understood the stations and retrogressions of the planets. Reflections 3g 2 ■4X0, PHILOSOPHICAL TKANSACTXONS. [aNNO 1753. on the eclipses of the sun and stars taught them anciently, by practice, some- thing of the parallaxes of the moon. Every thing was almost forgotten, about the time of Tsin chi hoam, 240 or 246 years before Christ. But it is evident that, before that time, the Chinese must have known something of the calculations of the eclipses of the sun and moon, and of some equations for reducing the mean motion to the true, and for calcu- lating the solstices. Mengtse, a classical author, who wrote before the burning of their books, mentions clearly enough, part at least of what is here said. They certainly knew indifferently well the proper motion of the fixed stars ; which was afterwards forgotten, for want of examining what was extant written in many books. On the 15 th of August, an ambassador from the king of Portugal arrived at Macao, with presents for the emperor of China- The queen-mother of the king of Portugal ordered the ambassador to desire, that Father Hallerstein, whom she personally knew, might come to him to Macao, with a mandarin sent by the emperor. The emperor consented to this without any difficulty, and dispatched the mandarin and Father Hallerstein to the ambassador. He will be here again in May. I am of opinion that the reigning emperor will never permit any mis- sionaries in the provinces ; and that they will find it very difficult to conceal themselves. But there is no appearance that we shall be sent away from Pekin ; on the contrary those who shall be sent thither, will be well received, if they have but the qualifications requisite. Letter 2. To Mons. De f Isle of the Royal Academy of Sciences at Paris. Dated Pekin, Nov. 18, 1751. p. 313. I had furnished M. Freret with a quantity of memoirs, as I had likewise done to others, both seculars, and those of our own society. I digested into order all that I had collected; and, in 1749, sent a complete treatise on the Chinese chronology, by two different ways, into France. I directed it to M. Freret, and to the fathers of our society at Paris. It was in 3 parts. I desired them to communicate it to you, and to Mons. de Mairan. I have had no account of the arrival of that treatise, in which I had laboured for more than 22 years past. It seemed to me necessary, on account of the great number of pieces, either printed or manuscript, which were sent hither on that subject. If I find that my treatise is lost, I can easily digest it into order again, from the rough draught which I have by me. Besides many astronomical observations, which I have punctually sent you, I have transmitted to you the treatise of Father Duchamp on the Indian astro- nomy, a collection of ancient approximations and occultations of the stars and planets, both by each other, and by the moon, and with the moon ; which I VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 413 had collected and made for determining the longitude and latitude of Pekin, &c. This year I have sent to Paris, by two different ways, a memoir, which had been desired of me, concerning the isles of Lequoyo, or Licoukicou, which Kempfer calls Roukou. It is a pretty long one. I had an opportunity of being well informed about these isles ; but there are many things yet wanting to be known. To this memoir I have added some remarks concerning the longitude of Namgazaki, and other places on the south coast of Japan, and the south coast of Coree, with its distance from Japan, and the island of Touyma, which, in the map of Father du Halde, is called Touyla Tao, or Touyla. It should be called Touy Ma. It is the isle Tsutsima. It depends on Japan. I have spoken here with several Coreans, who have been in that island. I have already sent to you observations made here to the close of the year 1750, and during this year. I now send you others of 1750; and others I in- closed to you at large in 1749 and 1750. I wait for some answer from you; and especially your opinion concerning the manner, in which I ought to dispose my memoirs concerning the Chinese astronomy. I am resolved to put my last hand to that work. But memoirs of that kind ought to be examined by persons intelligent and zealou^like yourself. At Petersburgh you must undoubtedly have seen what I wrote to Mr. Bayer about what the Chinese have said concerning the Huns and Turks. Dr. Morti- mer has written to me, that he had received from a nephew of Mons. Fourmont, a small piece on the origin of the Turks and Huns, as drawn from the Chinese books. I shall speak again of that subject in the memoirs which I have of the history of the great dynasty of Tang. There are a great number of very in- teresting things on what the Chinese have delivered at that time concerning the empire of the Persians, and its destruction by the Mahometans; concerning the Mahometans, and the assistance which they gave to Chinese emperors against their rebels; concerning the Christian religion, or the Tatsin, but in very ob- scure terms, concerning the sects and countries of the Indians, Japan, Coree, Tartary, and the countries between China and the Caspian sea, Thibet, and its princes. All these particulars may be of considerable service to unravel the eastern history from the year 500 of Christ to the year 1000 before him, and even much higher. There are here a great number of Lamas and Tartars, who have gone from Lassa, the capital of Thibet, to the lakes and mountains, where the sources of the Ganges are, and at Latac, &c. in the country to the north of Thibet and Latac ; but what they say is extremely confused; and this part of geography is still very little known to us here. 414 PHILOSOPHICAL TRANSACTIONS. [ ANNO 1753. XLVIII. A Lfitter of Mr. IVilliam Sherrington to Benjamin Franklin, Esq. concerning the Transit of Mercury over the Sun, on the 6th of Maij 1753, as observed in the Island of Antigua. Communicated by Mr. Peter Collinson, F.R.S. Dated Antigua, June 10, 1753. p. 318. Sunday, May 6, at 6" 7™ 31% he observed the western limb of Mercury to touch the western limb of the sun; and, at 6^ 10"" 37% he touched the same with his eastern limb, and totally disappeared. Lat. of the place 17° O' n. Lon. by estimation 6l° 45' w. from London. This was taken by a Graham's watch, and corrected by two altitudes taken by a most exquisite quadrant; which makes the true apparent time of the transit at 6^ 6™ 32' 32'". XLIX. Of the Barometer and the State of the fVeather, at Dublin, from March 7, 1752, to Feb. 1753. By James Simon, Esq. F.R.S. p. 320. This register contains the daily height of the barometer, with the state of the weather, as to wind, rain, &c. but is of no manner of consequence now. L. A Second Account of the Netv Method of Opening the Cornea, for taking away the Cataract. By Samuel Sharp, Surgeon to Guystiospital, and F.R.S. p. 322. Mr. S. here gives a short account of the success of his new method of remov- ing a cataract, with some observations on the principal phenomena attending this operation ; to which he adds a description of a further improvement of the operation itself. For a fuller view of the history of these cases, he has here set down the ages of the patients, the dates of the days on which they underwent the ope- ration, and the particular circumstance of its being done on one or both eyes. This was a list of 1 1 patients, from 48 to JO years of age, on whom the opera- tion had been performed. From this catalogue it appears, that the operation had been performed on \Q eyes ; and, from the most exact information, which he had been able to procure, the state of the success stood thus : ac, ad, af, ag, al, all whom had the ope- ration performed on both eyes, had every one of them recovered the sight of both eyes, to as great a perfection as can be supposed, without the help of the crystalline humour ; that is, they could read and WTite, with proper spectacles. The first of them, ac, had found so much benefit, as to be able to carry on the exercise of his profession, that of a surgeon, ah saw with both eyes, hut not so well as the other 5. He had received an account from the surgeon, who had attended her (in a distant country), that her eyes looked well, and her sight im- proved.* ai, another patient, at a distance froln London, had the operation done on one eye only ; which he recovered, as his correspondent informs him. VOL. XLVm.] PHILOSOPHICAL TRANSACTIONS. 415 SO as to see tolerably well, am, on one eye only, with which he already sees very well, ae had it performed on both ; one of which was lost, and the other recovered ; but continued inflamed, and could not bear nmch light, ab had it done on one eye only, which was lost. Both the eyes, in which the operation failed, were destroyed by the subse- quent inflammation ; but in the case of ab, the ill success was partly owing to the imperfection of the instrument ; a disadvantage that must frequently attend on the execution of new attempts. It was the first operation he had performed, and he had provided a knife with so thin a blade, that after he had passed through the cornea into the anterior chamber of the eye, the point was so blunted, that, on endeavouring to carry it through the cornea out on the other side, the blade bent, and he was apprehensive it might break : however, withdrawing it a little, he made 2 or 3 efl^brts, and succeeded in the incision, and the removal of the cataract. During this operation, the aqueous humour being discliarged, and the patient struggling, he wounded the iris ; which bled profusely, and continued for several days to discharge a great quantity of blood, and bloody ichor : and to this accident was imputetl the miscarriage of the operation ; though Mr. Da- vid aflirnis, that wounds of the iris had been very seldom followed with bad eflects in his practice. He had reserved the mention of ak's history to the last, because of its singu- laritv. She was altogether as blind as those whose cataracts are ripe ; but her's had the appearance of a beginning cataract, being of a light blue, and but little opaque. On making the compression, the crystalline did not advance through the pupil, as in the other instances : and he found, that if he exerted more force, he should soon evacuate all the vitreous humour. It was evident, by the great distance of the cataract behind the iris, that this disappointment did not arise from an adhesion to the iris : however, he had immediately recourse to the experiment of cutting through the capsula with the point of his knife ; hoping by that means to have set free the crystalline, but it gave him no assistance. He then passed the curette (a little scoop) through the pupil, and turned it several times round, in expectation of breaking the capsula; but found not the least re- sistance to his instruments ; so that both operations proved ineffectual ; the cir- cumstances being exactly the same in each eye. He had, in couching, met with cataracts of this nature ; but had no apprehension that he could not have dis charged, by the wound of the cornea, the matter of a cataract, in however fluid a state it might prove. * Some weeks after this paper was read, Mr. Sharp received an account, that tlie pupils of both eyes had contracted so much, as hardly to leave room for the admission of light; and it was appre- hended the patient would soon become blind. — Orig. 4l6 PHILOSOPHICAL TRANSACTIONS. [anNO 1753. Of all the 19, there was not one that escaped an inflammation; whereas, after couching, there are great numbers who have neither inflammation nor pain. But it was to be remarked, that notwithstanding the violent inflammation, which sometimes ensued after the incision of the cornea, even to an enlargement of the eyelids, and vesication of the tunica conjunctiva, the patient complained rather of a tenderness of the eye, on touching it, than of pain ; being generally exempt from those dreadful dartings m the head, which for the most part accompany an inflammation after couching. And he believed he might assert, that none suf- fered very much in that particular, except ae ; who was extremely bad, and lost the eye on that side where the pain was. It could not, he presumed, be difficult to conceive how these inflammations should excite such difi'erent symptoms, on reflecting, that in the incision of the cornea, the cornea only suffers ; and in couching, the conjunctiva, the sclero- tica, the choroides, and the tunica retina, are punctured; most of which organs are either tendinous or nervous ; and every surgeon knows the painfulness and obstinacy of inflammations, when they follow upon wounds and punctures of tendinous or nervous parts. He had not mentioned, in this comparison, the violence done to the vitreous humour; because he believed it did not occasion the subsequent pain; and because it seemed to be often as much or more injured in the new operation, without inconvenience. It had not occurred in any of these cases, that the inflammation had been so slight, as to disappear entirely in a fortnight, or 3 weeks ; most of them re- quiring 6 weeks, and some longer, for the total removal of them. The first 10 days, or more, the light was generally very offensive ; and he had observed, in 3 or 4 instances, that on forcibly opening the eyelids during that time, the patient was only sensible of a glare of light, though the eye then appeareri clear, and he afterwards recovered his sight. Which he mentioned to obviate the me- lancholy prognostic one would be disposed to make on a first examination. How- , ever, this was not to be understood as a constant fact ; some patients distinguish- ing objects immediately from the time of the operation. It sometimes happens, after this operation, that the pupil loses its circular figure ; which he imagines is owing to the great tenderness of the iris, which, on the least violence, is subject to be ruptured ; and he supposes in this operation, a slight pressure from the back or the flat of the blade may have produced the accident in the instances alluded to. Possibly the sudden dilatation of the pupil, from the rapid passage of the cataract through it, may sometimes occasion it ; but the following history would induce one rather to ascribe it to the cause which he first mentioned. Before he had thought of the knife for opening the cornea, he used the scis- sars, as Mons. Daviel directs ; and in a certain patient, after he had made the VOL. XLVIII.] PHILOSOPHICAL TRAKSACTIONS. 417 wound of the cornea, and was going to compress tlie eye, for the expulsion of the cataract, he discovered, that from the disturbance he had given to the hu- mours by the foregoing process, it was sunk almost as much as if it had been de- pressed by a couching needle. He therefore left it in that situation, and the man afterwards saw very well ; though the cataract remained visible something below the pupil. Now in this instance the cataract had not passed through the pupil ; and yet it was lacerated, so as to lose its circular form ; but whatever may be the cause, he did not find, that the accident itself proved prejudicial to the sight. He adds that when an incomplete gutta serena is complicated with the cataract, the operation is of no avail. It remains now to speak of the operation itself. In his former paper, after having described the manner of making the incision, he directed the operator to compress the inferior part of the globe of the eye with his thumb gently, till the cataract should be expelled through the incision of the cornea, on the patient's cheek; and in this method he had performed it on several subjects. But re- marking, that though on the evacuation of the aqueous humour, the crystalline readily advanced through the pupil into the anterior chamber, yet that it required some force to expel it from its membrane through the wound of the cornea, and in that action it sometimes suddenly drew after it a portion of the vitreous hu- mour, he changed his method, and no longer pressed the eye when once the crystalline was in the anterior chamber, but immediately stuck the point of his knife into the body of it, and extracted it contained in its capsula, without spilling any of the vitreous humour. This new process, he supposes, would be found of considerable advantage, as it would in a great measure remove the danger of evacuating the whole, or too much of the vitreous humour : though it might be observed, to the praise of this operation, that, contrary to expectation, a large quantity of this humour, per- haps a 3d part, or more, had been sometimes discharged, without any bad con- sequence. He supposes, that the great and sole benefit arising from this improvement, is the easy separation of the crystalline from the bed of the vitreous humour, so that none of this humour shall be evacuated. But perhaps it would also be ap- proved of, as it would render unnecessary the measure prescribed by Mons. Da- viel, of wounding the membrane of the crystalline, before we proceed to the ex- traction of the crystalline itself: to which purpose he advises the flap of the cornea to be suspended with a small spatula ; then, with a pointed cutting needle, to wound the surface of the crystalline; after which, to introduce the same spa> tula through the pupil, in order to detach the cataract from the iris, and then proceed to the expulsion. He had here recited these processes of M. Daviel's operation, which are calcu- VOL. X. 3 H 418 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. lated mertly to procure an easy separation of the crystalline from the vitreous humour: but they are difficult to the operator, fatiguing to the patient, and, he should hope, altogether needless, if the knife be used in the manner which he has recommended : for whether the capsula of the crystalline be nothing more than the duplicature of the membrane of the vitreous humour, or whether it be a proper coat, which is also covered by the membrane of the vitreous humour ; in either case, since by compression the crystalline advances with so much facility through the pupil, it will be easily seized by the knife, and removed from the vitreous humour, with its inveloping membrane : whereas, in making an inci- sion on the surface of the crystalline, and wounding its capsula, the crystalline will frequently slip out of the capsula, which will be left behind : and in fact this has happened to M. Daviel, who advises pincers, and other instruments, to extract the remaining membrane. But he observes, in regard to the capsula of the crystalline, that should the humour slip out of it, before it be seized by the knife, it possibly will waste ; for in milky cataracts, when the fluid is discharged, the membrane in length of time wastes : whole cataracts, with the inveloping membrane likewise, sometimes waste : and in one of his patients, the crystalline, from the mere pressure in the operation, burst out of its capsula, which he left in the eye ; but in some weeks it entirely wasted. However, if the removing of the capsula should, by future experience, be found necessary, it may be conve- niently done by the curette ; one of the instruments M. Daviel recommends for that purpose/ This instrument may be also used for the extraction of a cata- ract, which has been broken to pieces by the couching needle in a former opera- tion, and for the removal of the capsula of a bag-cataract, when the fluid only has been discharged, and the bag remains behind ; but it will be most eminently useful in detaching the crystalline from the back part of the iris, when any portion of it happens to adhere : which circumstance would render the operation fruit- less, without such a precaution. It had not happened, in any of the cases treated, that either during the ope- ration, or after the operation, the iris had been pushed forwards, or insinuated itself through the wound of the cornea, forming a staphyloma ; but M. Daviel speaks of it as an occurrence he had met with, and says it may easily be replaced by the small spatula. Mr. S. hopes that when this operation is more generally practised, ingenious men will render it still more perfect : and he should not be surprised, if the use of a speculum oculi should hereafter be esteemed an improvement : but then it must be contrived so, as that it shall not compress the globe of the eye ; or, if it does, the operator must be careful to remove it in the instant the incision is making, lest, by continuing the pressure after the wound is made, all the humours should suddenly gush out. VOL. XLVia.] PHILOSOPHICAL TRANSACTIONS. 419 LI. An Attempt to explain an /Ancient Roman Inscription, cut on a Stone lately found at Bath. By John JVard, LL.D., F.P.R.S. p. 332. The stone was discovered on the 2'2d of June last, about 5 feet under ground, in digging the cellar of a house, rebuilding at the lower end of Stall-street. Among the rubbish of the old house, when it was pulled down, was a large quantity of walling stone, which had on it the marks of fire : so that probably some building had formerly stood there, which was burnt. And in sinking the ground about 4 or 5 feet lower th^n the stone, they found 2 coins of the em- peror Carausius, in base metal, and very much defaced. In July 1727 the beautiful gilt head, which is now preserved in the town house, was dug up at the other end of this street, not far from the King's bath, about 16 feet below the surface of the earth, as they were making a common sewer through the town. The stone, on which this inscription is cut, has been generally taken for a pedestal, either of a statue, or some other solid body, which it once supported. Though from the appearance of the horizontal plane at the top Mr. Prince Hoare, the ingenious statuary at Bath, is of opinion, that nothing was formerly placed on it ; and supposes that the sinking in the middle, with the 2 lines erased, one on each side, might be made merely for ornament. Besides, the face and 2 sides only are finished ; the back being flat, as if it was designed to stand against a wall. The height of it, which is very near 3 feet ; as also the form both of the stone itself, and the plane above mentioned ; appear by the draughts of them taken by Mr. Hoare. From a careful examination of the whole inscription, as it appeared in the cast taken by Mr. Hoare, Dr. W. copied it in the draught of the stone ; and endeavoured to express the several letters in their proper form and proportional size, with the ligatures, divisions of the words, and their situations in each line, in the most exact manner he was capable of doing it. And on considering the whole in this view, he offers the following reading in words at length, as what appears to him the most probable : Locum religiosum, per insolentiam erutum, virtuti et numini Augusti repurgatum reddidit Caius Severius Emeritus, centurio, sua pecunia. Dr. Ward thinks this a monumental stone, brought from some Roman burial place. But who the reigning emperor was, at the time this stone was set up, no in- timation is given in the inscription. Though, if one may be allowed to conjec- ture, the form of the letters suits very well with some others in the reign of 3 H 2 420 PHILOSOPHICAL TRANSACTIONS. [anNO 1753. Severus. And perhaps no time was more open for such licentious practices, as might justly merit the name insolentia, than the loose reign of Commodus ; who though he was not the immediate predecessor of Severus, yet died but a few months before he came to the empire. Besides, we have two other inscriptions found in Britain, addressed Numinibus Augustorum ; both which are thought to relate to Severus and his elder son Caracalla, after he was joined with his father in the government. Nor can there be any doubt of this, as to one of them at least ; which is an altar, and has on one side of it the names of both his sons, Caracalla and Geta, as consuls that year. So that on the whole. Dr. W. can find no other period of time so probable for fixing the date of this inscription. LII. On some Electrical Experiments, made at Paris. By Mr. Benjamin Wilson, F.R.S. p. 347. Mr. W. being at Paris, M. Mazeas informed him that Dr. le Monnier, some months ago, h:id read a paper at a meeting of the Royal Acad, of Sciences, in which he told them, that he had great reason to believe the electric matter did not come from the earth at all, but from the air. On Mr. W. mentioning this to the Doctor, he found him still of the same opinion. As there was a conveni- ent apparatus in his apartment, Mr. W. proposed making the experiments : for he always thought that the electric matter came from both, but principally from the earth ; and that probably a difference of 10 to 1 would be perceived, on making the experiments. The machine was suspended by silk lines in such a manner, that every part of it was not less than '2 feet distant from any non-electric. The lines were dried by a chafing-dish of fire made with charcoal, as was also the glass globe ; and every other precaution was strictly observed, that seemed necessary for making the experiments. The doctor appeared to be well versed in electrical inquiries, and showed great judgment in conducting the whole. He got upon the suspended apparatus him- self, and rubbed the globe with both his hands ; while another person, who was likewise suspended, turned the wheel of the machine. Close to the globe was a slender slip of lead ; at one end of which was fastened some brass tinsel, to serve as a collector of the electric matter. The other end of the lead had a communication with a tin tube, which was supported by silk lines about a foot in length : and as this tube hung higher than could be reached, another was hooked to it by means of a wire which hung down to a convenient distance. As Mr. W. stood on the floor, he took hold of this last tube, while the glass was rubbed, that the apparatus, and the persons on it, might lose as much of their natural electricity as possible under such circumstances. On removing his VOL. XLVm.] PHILOSOPHICAL TRANSACTIONS. 4'21 hand, .nnd afterwards approacliing the tube, sometimes with his finger, and at Other times with a key, they observed very small explosions, which were little more than just sensible. Mr. W. then desired one of the doctor's servants, who also stood upon the floor, to lay hold of the suspended apparatus on which the doctor was mounted, while the friction of the globe was continued. Immediately on Mr. W. ap- proaching the tube as before, with his finger, and then with the key, a very great difference was observed; for now the explosion was very large compared with the former trials. Dr. le Monnier desired the experiments might be repeated: which was done several times, and to all appearance the differences were the same. He was perfectly satisfied that the experiments were fairly made, and that the explo- sion was much greater when the apparatus communicated with the earth, than when it communicated with the air only. hill. Electrical Experiments, with an Attempt to Account for their Several Phe- nomena, jitso some Observations on Thunder-clouds. By John Canton, M.A., F.R.S. p. 350. Exp. 1. — From the ceiling, or any convenient part of a room, let 2 cork- balls, each about the size of a small pea, be suspended by linen threads of 8 or 9 inches in length, so as to be in contact with each other. Bring the excited glass tube under the balls, and they will be separated by it, when held at the distance of 3 or 4 feet ; let it be brought nearer, and they will stand farther apart ; entirely withdraw it, and they will immediately come together. This ex- periment may be made with very small brass balls hung by silver wire; and it will succeed as well with sealing-wax made electrical, as with glass. Exp. 2. — If 2 cork balls be suspended by dry silk threads, the excited tube must be brought within 18 inches before they will repel each other; which they will continue to do, for some time, after the tube is taken away. As the balls in the first experiment are not insulated, they cannot properly be said to be electrified : but when they hang within the atmosphere of the excited tube, they may attract and condense the electrical fluid round about them, and be separated by the repulsion of its particles. It is conjectured also, that the balls at this time contain less than their common share of the electrical fluid, on account of the repelling power of that which surrounds them ; though some perhaps is continually entering and passing through the threads. And if that be the case, the reason is plain, why the balls hung by silk, in the 2d experiment, mvist be in a much more dense part of the atmosphere of the tube, before they will repel each other. At the approacli of an excited stick of wax to the balls, iu the first experiment, the electrical fire is supposed to come through the threads into the balls, and be condensed there, in its passage towards the wax : for, ac- 4'2'2 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. cording to Mr. Franklin, excited glass emits the electrical fluid, but excited wax receives it. Eip. 3. — Let a tin tube, of 4 or 5 feet in length, and about 2 inches in dia- meter, be insulated by silk ; and from one end of it let the cork balls be sus- pended by linen threads. Electrify it, by bringing the excited glass tube near the other end, so as that the balls may stand an inch and a half, or 1 inches apart : then, at the approach of the excited tube, they will by degrees lose their repelling power, and come into contact ; and as the tube is brought still nearer, they will separate again to as great a distance as before : in the return of the tube they will approach each other till they touch, and then repel as at first. If the tin tube be electrified by wax, or the wire of a charged phial, the balls will be affected in the same manner at the approach of excited wax, or the wire of the phial. Exp. 4. — Electrify the balls as in the last experiment by glass ; and at the ap- proach of an excited stick of wax their repulsion will be increased. The effect will be the same, if the excited glass be brought towards them, when they have been electrified by wax. The bringing the excited glass to the end, or edge of the tin tube, in the 3d experiment, is supposed to electrify it positively, or to add to the electrical fire it before contained ; and therefore some will be running off" through the balls, and they will repel each other. But at the approach of excited glass, which likewise emits the electrical fluid, the discharge of it from the balls will be diminished ; or part will be driven back, by a force acting in a contrary direction ; and they will come nearer together. If the tube be held at such a distance from the balls, that the excess of the density of the fluid round about them, above the common quantity in air, be equal to the excess of the density of that within them, above the common quantity contained in cork : their repulsion will be quite destroyed. But if the tube be brought nearer ; the fluid without, being more dense than that within the balls, it will be attracted by them, and they will recede from each other again. When the apparatus has lost part of its natural share of this fluid, by the ap- proach of excited wax to one end of it, or is electrified negatively ; the electrical fire is attracted and imbibed by the balls to supply the deficiency ; and that more plentifully at the approach of excited glass, or a body positively electrified, than before ; whence the distance between the balls will be increased, as the fluid sur- rounding them is augmented. And in general, whether by the approach or re- cess of any body; if the difference between the density of the internal and external fluid be increased, or diminished ; the repulsion of the balls will be increased, or diminished, accordingly. Exp. 5. — When the insulated tin tube i» not electrified, bring the excited VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 423 glass tube towards the middle of it, so as to be nearly at right angles with it, and the balls at the end will repel each other ; and the more so, as the excited tube is brought nearer. When it has been held a few seconds, at the distance of about 6 inches, withdraw it, and the balls will approach each other till they touch ; and thfen separating again, as the tube is moved farther off, will continue to repel when it is taken quite away. And this repulsion between the balls will be increased by the approach of excited glass, but diminished by excited wax ; just as if the apparatus had been electrified by wax, after the manner described in the 3d experiment. Exp. 6. — Insulate 2 tin tubes, distinguished by A and b, so as to be in a line with each other, and about half an inch apart; and at the remote end of each let a pair of cork balls be suspended. Towards the middle of A, bring the excited glass tube ; and holding it a short time, at the distance of a few inches, each pair of balls will be observed to separate ; withdraw the tube, and the balls of A will come together, and then repel each other again ; but those of b will hardly be affected. By tbe approach of the excited glass tube, held under the balls of A, their repulsion will be increased : but if the tube be brought, in the same manner, towards the balls of b, their repulsion will be diminished. In the 5th experiment, the common stock of electrical matter in the tin tube is supposed to be attenuated about the middle, and to be condensed at the ends, by the repelling power of the atmosphere of the excited glass tube, when held near it. And perhaps the tin tube may lose some of its natural quantity of the electrical fluid, before it receives any from the glass ; as that fluid will more readily run off from the ends or edges of it, than enter at the middle : and ac- cordingly, when the glass tube is withdrawn, and the fluid is again equally dif- fused through the apparatus, it is found to be electrified negatively : for excited glass brought under the balls will increase their repulsion. In the 6th experiment, part of the fluid driven out of one tin tube enters the other ; which is found to be electrified positively, by the decreasing of the repul- sion of its balls, at the approach of excited glass. Exp. 7- — Let the tin tube, with a pay- of balls at one end, be placed 3 feet at . least from any part of the room, and the air rendered very dry by means of a fire: electrify the apparatus to a considerable degree ; then touch the tin tube with a finger, or any other conductor, and the balls will still continue to repel each other ; though not at so great a distance as before. The air surrounding the apparatus to the distance of 2 or 3 feet, is supposed to contain more or less of the electrical fire, than its common share, as the tin tube is electrified positively, or negatively ; and when very dry, may not part with its overplus, or have its deficiency supplied so suddenly, as the tin ; but may continue to be electrified, after that has been touched, for a considerable time. 424 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753, Exp. 8. — Having made the Torricellian vacuum about 5 feet long, after the manner described in the Phil. Trans, vol. xlvii. p. 3/0, or p. 236 of this vol. of these Abridgments, if the excited tube be brought within a small distance of it, a light will be seen through more than half its length ; which soon vanishes, if the tube be not brought nearer ; but will appear again, as that is moved farther oft'. This may be repeated several times, without exciting the tube afresh. This experiment may be considered as a kind of ocular demonstration of the truth of Mr. Franklin's hypothesis ; that when the electrical fluid is condensed on one side of thin glass, it will be repelled from the other, if it meets with no resistance. According to which, at the approach of the excited tube, the fire is supposed to be repelled from the inside of the glass surrounding the vacuum, and to be carried off" through the columns of mercury , but as the tube is with- drawn, the fire is supposed to return. Exp. Q. — ^Let an excited stick of wax, of 24- feet in length, and about an inch in diameter, be held near its middle. Excite the glass tube, and draw it over one half of it ; then, turning it a little about its axis, let the tube be excited again, and drawn over the same half; and let this operation be repeated several times ; then will that half destroy the repelling power of balls electrified by glass, and the other half will increase it. By this experiment it appears that wax also may be electrified positively and negatively. And it is probable, that all bodies whatever may have the quantity they contain of the electrical fluid, increased, or diminished. The clouds he has observed, by a great number of experiments, to be some in a positive, and others in a negative state of electricity. For the cork balls, electrified by them, will sometimes close at the approach of excited glass ; and at other times be separated to a greater distance. And this change he has known to happen 5 or 6 times in less than half an hour ; the balls coming together each time, and remaining in contact a few seconds, before they repel each other again. It may likewise easily be discovered, by a charged phial, whether the electrical fire be drawn out of the apparatus by a negative cloud, or forced into it by a positive one : and by which- ever it be electrified, should that cloud either part with its overplus, or have its deficiency supplied suddenly, the apparatus will lose its electricity : which is fre- quently observed to be the case, immediately after a flash of lightning. Yet when the air is very dry, the apparatus will continue to be electrified for 1 0 or 15 minutes, after the clouds have passed the zenith; and sometimes till they appear more than half-way towards the horizon. Rain, especially when the drops are large, generally brings down the electrical fire ; and hail, in summer, he believes never fails. When the apparatus was last electrified, it was by the fall of thawing snow ; which happened so lately as on the 1 2th of November ; that being the 26th day, and 6 1st time, it has been electrified, since it was first VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 425 set up; which was about the middle of May. And as Fahrenheit's thermometer was but 7 degrees above freezing, it is supposed the winter will not entirely put a stop to observations of this sort. At London, no more than 1 thunder storms have happened during the whole summer: and the apparatus was sometimes sa strongly electrified in one of them, that the bells, which have been frequently rung by the clouds, so loud as to be heard in every room of the house, the doors being open, were silenced by the almost constant stream of dense electrical fire, between each bell and the brass ball, which would not suffer it to strike. Mr. C. concludes this paper with the following queries : 1 . May not air, suddenly rarefied, give electrical fire to, and air suddenly condensed, receive electrical fire from clouds and vapours passing through it? 2. Is not the aurora borealis, the flashing of electrical fire from positive, to- wards negative clouds at a great distance, through the upper part of the atmo- sphere, where the resistance is least? LIF. Extract of a Letter from Professor Bose. dated Wtttemberg, Aug. J, 1753. JVith Observations on it by Mr. Wm. fVaison, F. R. S. p. 358. In the beginning of August 1752, after great and continued rains, many of our rivers overflowed the neighbouring grounds, more or less according to their level, to a considerable distance; and the quantity of water was so great, that in some places it was not discharged for more than a week. More particularly the river Unstrut in the territory of the landgrave of Thuringue required a long time to empty itself, not only as that river runs over a large tract of country, but also as between Artern and great Jena, where this river joins the Sales, its bed in several places is very much confined. When the inundation was abated, it was observed from the little city Laucha quite up above Artern, not only on the fields and meadows, but also on the bushes and trees, that there was a green and very tough viscous slime, which by the help of a stick could be drawn out to 2 or 3 ells in length. The subsequent heat of the sun dried this matter, and it appeared like wool on the bushes ; but the fields, when seen at a distance, seemed as if covered with sand. This matter had a smooth appearance outwards, but within was like a sheep's skin. Down- wards next tlie ground it had a sort of wool ; and when the whole was washed with soap, it whitened, and appeared like a clean fleece of white wool. Of this substance the country people soon made wicks for their lamps, and several lined their clothes with it, as they would with fur. It was further observed, that where this substance was mowed off from the meadows, the grass under it was quickly dried up; but, where it was not removed, the grass in the following December was as green and fresh as in the spring. Thus far Mr. Bose. On which Mr. Watson observes, that the veget- VOL. X. 3 I 40^ FHILOSOPHICAL TBANSACTIONS. [aNNO 1733. able substance, which, on the specimen sent over by the professor, he has intitled " a sort, perhaps, of alcyonium molle," is a species of that genus of plants, which the more modem botanists call byssus. And it is of that species, or a very slight variety from it, which is called by Dillenius, in his Historia Muscorum, byssus tenerrima viridis velutum referens. It is also mentioned and figured by Micheli in his Nova Plantarum Genera, under the title of byssus terrestris viridis herbacea et mollissima, filamentis ramosis et non ramosis. This genus of plants, in the order of nature, comes between the mosses and fungi. The specimen now sent, being white on one side, arises from its either being washed or bleached by the sun; for when wet, according to Mr. Bose, it was green; and this colour is mentioned both by Dillenius and Micheli in their several denomi- nations. This vegetable is found in England, as well as in many parts of Europe, in moist meadows, covering the ground like a carpet, and sometimes to a great extent. We must be careful, however, how we connect the substance in question, and others of the same genus with the jSuVo-of of the ancient Greek writers, or the byssus of the Latin. What that substance was, has been matter of great con- troversy. This is certain, that garments made of it were the apparel of the rich. And in the New Testament, St. Luke, in the parable of the rich man and Lazarus, says of the former, as a mark of his opulence, IviSiSda-niTo Trof 425, et seq. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 42/ therefore, according to Mr. Short's computation, magnified about 130 times. He was placed in the most commodious situation for observing the egress; his smoked glass was fixed perpendicular to the axis of his telescope within a close tube;, and he always used the same part of this glass. He took, notice, that the interior contact of Mercury's and the sun's limbs, at lO'' 18'" 41% was very rapid, having observed it with a green-coloured glass held over the smoked glass: immediately after which, looking through the smoked glass only, he perceived that a small thread of light was still visible be- tween the limbs, before what he calls the second contact took place, which was not till 4 seconds after; that the exterior contact appeared stationary, or seemed to last 6 or 7 seconds; that having observed the total egress with the coloured glass on the smoked one, he brought Mercury on the sun's limb again, by re- moving the coloured glass; and that the second total egress did not happen till 6 or 7 seconds after the first. When he observed him at the distance of about 3 of his diameters from the sun's limb with both the glasses, he remarked that the same distance seemed diminished, and Mercury's diameter increased. That the part of the sim's limb where Mercury went off, to the extent of 6 degrees of circumference, seemed under much the same configuration, as the illumi- nated limb of the moon about the quadrature, somewhat uneven and undulating. The same looked also redder than the rest of the disk. This was about 18 or 20 seconds before Mercury disappeared, and was seen through the smoked glass alone; for when the green glass was applied, the appearance in a manner vanished. The evening before the transit he viewed the sun with different coloured glasses, variously combined with each other, and with a smoked glass; and found, that a green glass before the smoked one did best; the sun appearing of a silvery hue, like the moon, and the spots and the limb exceedingly well defined. M. de Barros, having thus described the particular phenomena, ingeniously attempts to account for them all, from this single supposition ; that the disk of the sun, and of Mercury seen on it, are environed with a certain corona of light (like that which Sir Isaac Newton calls the circle of aberration or dissipation in refracting telescopes) by which the apparent diameter of the sun is enlarged, and that of Mercury contracted. But as this gentlemen made use of a reflecting telescope, and as no such circle, from the known principle of reflection, can take place in such a telescope, if well made, as Sir Isaac has proved long since; Mr. S. thinks it not worth while to pursue him through all his particular supposi- tions; but only to show that his hypothesis has really no foundation. Sir Isaac, as before hinted, remarks, that the images of all objects seen in refracting telescopes, are surroundeil with a circle of aberration ; which is always less, the longer the telescopes are. In his optics, tn avoid the indistinctness arising from this circle, he would propose catadioptric telescopes, in which, if 3 I '2 428 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. the speculums, under limited apertures, be justly figured, no such circle of aber- ration can confuse the image; but if the speculums are of a spherical figure, with too large apertures, then a circle of aberration will take place; as it also will when the figure deviates from the circular towards the hyperbolic, even under a small aperture, and the same thing will happen, if the spherical figure be inaccurate. About 3 days from the change of the moon, her whole body is visible; that part of the limb, which is directly enlightened by the solar rays appearing to the naked eye, as an arc of a greater circle than the other, which receives the reflex light from the earth. Look through a refracting telescope, and you will per ceive the apparent diiFerence of these circles very much diminished; and if they be viewed with a good reflector, they will be perfectly reduced to an equality, even if measured with a micrometer in the focus. If a reflecting telescope, well constructed, be directed any considerable time to the sun, such a circle of aberration will be generated, from the little spe- culums being heated, and thereby its figure altered, from the sun's rays falling condensed on it from the great one; and if it continues long under this circum- stance, the image will be rendered utterly indistinct and confused. This we were thoroughly convinced of at the above-mentioned transit of Mer- cury; for a good reflector, which we used in taking, with the micrometer, the differences of right ascension and declination between the planet and the sun's limb, having been a good while exposed to the direct rays, was found at last to give a very indistinct image; but was restored to its former degree of perfection, by turning it from the sun, and screwing off" the eye-piece, so as to admit the cool air into the great tube, by which the over-heated small speculum soon re- ■ covered its due temper and figure. The last-mentioned effect is scarcely sensible in the less reflectors of small apertures ; but in those of large ones it is very con- siderable. Dr. Bevis, Mr. Canton, and Mr. Bird, who viewed Mercury going off the sun, with very good reflectors of dififerent lengths, assured him, they saw him quite distinct, and free from any corona, or circle of aberration, and the sun's limb perfectly well defined. And he appeared to Mr. S. through a reflector of 4 feet focus, magnifying about 135 times, as truly defined as he could wish to see a black circle on a white ground. On this occasion however Mr. S. takes notice, that during the whole time of this transit of Mercury, the air was perfectly calm with us : but that, in the last two transits of Mercury over the sun, viz. in the years 1736 and 1743, both the sun's and Mercury's limbs appeared to him indis- tinct, and surrounded with something like what this gentleman calls a luminous crown, or circle of aberration ; though Mr. S. at both these times made use of reflecting telescopes, which he had by former trials esteemed good. But it is to VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 420 be observed that, during both these transits, there was a constant hard gale of wind ; and as lie had, by other observations, formerly found that the images of the planets, in the night-time, did not appear so distinct in windy weather as when it was calm, he therefore imputed the indistinctness of the sun's and Mer- cury's limbs to the air's being agitated by the wind.* Of this we may be made sensible by a familiar instance : Suppose a vessel full of water, having any thing lying at the bottom, as a shilling, the water being at rest; you will then perceive the image of the shilling distinctly ; but if you give any commotion to the water, the image of the shilling will then appear indistinct and confused. Somewhat analogous to this is this other appearance : if you look through a, telescope at any of the planets, when the stars appear hazy, dim, and languid, you will see them distinctly : but look at them again, when the stars appear most bright and sparkling, you will then find their images less distinct. This may be accounted for by the just-mentioned instance of the vessel of water, by supposing air instead of water. And if we consider the infinite number of heterogeneous particles which continually float in the air, and suppose these to be at rest, or put into motion, we shall find that it is not at all surprizing, that we see the images of objects placed beyond the medium of air, more or less distinct. We are not so sensible of this indistinctness, arising from the agitation of the air, in re fracting telescopes, as in reflectors : because the errors of reflexion, caused by any irregularity in their figure, or confusion in the air, are about 5 or 6 times greater than the same errors in refraction ; even though both telescopes magnify the same number of times; as has long been demonstrated. We also took notice of M. de Barro's first phenomenon ; viz. the seeming greater velocity of Mercury when he was near the egress : which we thus ac- counted for. When he was at a considerable distance from the limb, there being nothing near enough to refer his velocity to, he seemed in a manner stationary ; but being advanced near the sun's edge, we could refer his motion to that with ease; which thus becoming sensible, it might be esteemed rapid, in comparison of the former. Mr. S. had often made the same remark on the gradual approach of two luminous bodies, as the appulse of the moon's lucid limb to a star or planet. The expedition with which the author observed his 2d phenomenon, is extra- ordinary ; viz. that he should first observe what he names the final contact ; 2dly, that he should take away his green glass ; and thirdly, that he should be able suddenly to alter the conformation of his eye, so as to see distinctly with a much greater influx of light, and then take another observation, and all in the short * Since this paper was read, Mr. Short has been informed by M. le Monnier, the French king's aitronomer, that, during the last transit at Paris, they had a hard gale of wind fiom the n. £, — Orig^ 430 PHILOSOPHICAL TRAKSACTIONS. [aNNO 1753. space of 4 seconds ! On the whok, it may be concluded, that the several phe- nomena, observed by this gentleman, in the transit and egress of Mercury, were owing to indistinctness of vision, arising either from the eye, the telescope, or the air; and that this alone may account for them all, without having recourse to supposed circles of aberration ; which can never possibly exist in a well-con- structed reflecting telescope. LVI. An Explanation of an Obscure Passage in Albert GirarcTs Commentary on Simon Stevin's Works, p. 169, 170. By Mr. Simson, Prof. Math. Glas- gow. Communicated by Philip, Earl Stanhope, p. 368. " Puis que je suis entre en la matiere des nombres rationaux, j'adjousteray encore deux ou trois particularitez, non encor par cy devant practiquees, comme d'expliquer les radicaux extremement pres, &c." The first thing Albert Girard gives in this place is a method of expressing the ratio of the segments of a line cut in extreme and mean proportion, by rational numbers, that converge to the true ratio. For this purpose he takes the pro- gression 0, 1, 1, 2, 3, 5, 8, 13, 21, &c. every term of which is equal to the sum of the two terms that precede it, and he says, any number in this progression has to the following, the same ratio (nearly) that any other has to that which follows it. Thus 5 has to 8 nearly the same ratio that 8 has to 13; conse- quently, any 3 numbers next one another as 8, 13, 21, nearly express the seg- ments of a line cut in extreme and mean proportion, and the whole line; so that 13, 21, 21, (n. B. 13 is wrong printed for the second number, instead of 21) constitute near enough an isosceles triangle, having the angle of a pentagon; i. e. whose angle at the vertex is subtended by the side of a pentagon in the circle described about the triangle. Now this will be plain, if it be shown, that the squares of the numbers in this series are alternately lesser and greater by an unit, than the product of the two numbers on each side. Thus, in the 4 numbers, 5, 8, 13, 21, the square of 8 is a unit less than the product of 5 and 1 3 ; but the square of 1 3 that next follows 8, viz. 169, is a unit greater than 8 times 21, or 168; and so on con- stantly. Case 1 . If a, b, c, be such numbers, that a -\- b = c, and ac = bb -\- 1. Then, if d be taken so that d = b -{- c; then shall bd-\- 1 = cc. For, be- cause d =■ b + c; bd -{- 1 shall be ^ bb -\- be -\- 1 = ac -\- be, which is = {a -\- b) X c = cc: ergo bd + 1 = cc. Case 2. If a, b, c, be such, that a -\- b= c, and ac -{- 1 = bh. Then, if d be taken so that d-= b -\- c; then shall bd=^ cc -{■ 1, For, be- cause bd = bb -{- be z= ac -\- be -\- \ = {a + b) X c -j- 1 = cc -f 1. Problem. Having given the number a, in case 1 ; to find b and c, i. e. having TOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 431' given a, to find b such, that t/) + 1 = {ac ^=:.") aa -\- ab \ then is bb — ab ■=. aa — 1 : and therefore b ■=. \a -\- \ ^ baa — 4. Hence, to make b a rational in- teger number, baa — 4 must be a square, which it will be, if a =: l ; and then b will also be 1, and c will be 1: and having continued the series, every number will have the properties mentioned. The 2d thing which Alljert Girard mentions, is a way of exhibiting a series of rational fractions, that converge to the square root of any number proposed, and that very fast. He tells nothing about the way of forming it, and only gives the two following examples, viz. He says, ^"2 is equal nearly to ^i^: or, if you would have it nearer, to ^-^-S-^ . His other example is of a/ 10, which, he says, is nearly equal to 3^y/,»^, i. e. to '-jS^jV-s' . And these are the fractions your lordship has turned, at first sight into continued fractions of the same value.* The way of making a series of rational fractions, which converge to the square root of any number proposed, in such a manner, that the square of the nume- rator of any of them being lessened by a unit, or in some cases increased by a unit, the remainder or sum, divided by the square of the denominator, shall be exactly equal to the number proposed, depends on the following propositions. Prop. 1. Let a be any number proposed, and - be such a fraction, that — ^^— ■= a, i. e. bh = ace + 1 ; then if two other fractions be taken, one of which is b • * c -, the first divided by the proposed number a, and the other is y the reciprocal of the first fraction; then the fraction — —. — , whose numerator is the sum of the products of the numerators, and of the denominators of the fi-actions - and — ; and its denominator the sum of the products of the numerators, and c ac b c of the denominators of the fractions and -, shall have the same property with the fraction -i.e. ^^ — 7Tb )'' ~ ~ "* because bb = ace + 1, therefore bb — ace := 1 , and squaring b* — lab-c'' + a''c* = 1 . And adding 4a^'c^ gives b* + 2a6^c^ + aV = 4ab\'' + 1. Hence £^l±ggl=-L = a. Prop. 1. If - be such a fraction, that — — = a, i.e. bb -{■ 1 := ace, all • N. B. That the continued fraction here alluded to, for expressing the square root of 10, waa i — TT __ f TT — -^, ice. ad infinitiun. — Orig. 432 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. other things remaining as in prop. 1 ; then shall the fraction — ^t_fff formed as there described, be such, that - — -r^-:.r^^^ = a. ibc ' C^bcj^ For because bb -^ I = ace, then ace — bb = 1; and squaring, b* — 2aiV + aV= 1. Hence, as in the foregoing, it will follow, that ebb + accj^ — 1 = a. C^bcJ" Prop. 3. Let the fraction - be such, that — ~ — = a, i. e. bb = ace + 1; also let - be another fraction, having the same property with -, i. e. such, that dd = aee + 1. Then, if from the fraction -, and the two others mentioned be in prop. 1, viz.—, and 7, a new fraction be formed, in the same manner as the fraction — -7 — was formed from -, and the same two - and 7, which fraction will 2bc c ac b be , , ; this new fraction shall have the sanie property with the other two b J d . (bd + ace)'' — 1 -and -,i.e.-^^-5-^_-. = a. Prop. 4. The same things being supposed as in prop. 3, except that bb, in- stead of being equal to ace + 1 , as there, is equal to ace — 1 , or bb -{- 1 ^ ace; it will follow, by the like steps as in prop. 3, that — - "^ = a. Prop. 5. If likewise cP be equal to aee — 1, as well as b^ = ace — 1, all other things remaining as in prop. 3, then shall {bd -\- acey = a X {cd -{- bey + 1» Cbd + ace)* — 1 _ Prop. 6. But if i^ = ace + 1, and d^ =■ aee — 1, all other things remaining as (bd + acej'^ + 1 'bTJ' Now, let a be any number proposed, and let the fraction - be such, that either — '^^— = a, or — — = a, and take the fractions — and-r, before described; cc cc ac o then the series of fractions converging to \^ a, will be as follows: -, —\- = the first term of the series. b' aci c *i + ^ = ^the2dterm. 1 , 2oc e Every term is formed from the preceding; and bd + ace L tV, co(n'oio-i itself, in Herodotus, is corrupt. The Greek chronology, like that of other nations, has been generally carried up too high ; the natural consequence of ignorance, and a defect of memoirs. This is only now to be corrected by persons of learning and abilities, capable of examining and comparing things with each other. LX. An Additional Remark to one of Mr. JV. Walson, F.R.S. in his Account of the Abbe Nonet's Letter on Electricity. By T. Birch,* D.D. Sec. U.S. Mr. Watson, in a note upon his account of the ninth letter of the Abbe Nollet concerning electricity, read before this Society on the 17 th of May 1753, * Dr. Tho. Birch was born at Loudon in 1705. His parents were quakers, and they intended him for trade ; but the love of learning prevailed, in which he was permitted to pursue his inclination, on condition that he should provide for himself. Hence he became usher successively in three schools kept by quakers. Having quitted the Society of the Friends, however, in 1730 he was ordained deacon, and the next year priest ; about which time he obtained a living in Gloucestershire, and afterwards that of Ulting in Essex. In 1734 he became domestic chaplain to Lord Kilmarnock, who was executed in 1746 for his share in the rebellion. In 1735 Dr. Birch was elected f. r. s. and f. a. s. VOL. XLVni.] PHILOSOPHICAL TRAKSACTlbNS. 447 takes notice, that as the electrical attraction has been observed so early, as to be mentioned by Theophrastus ; so its luminous appearance, though only considered as a meteor, is mentioned by Plutarch in his life of Lysander, Pliny, and other ancient as well as some modern authors. Seneca particularly affirms, that Gy- lyppo Syracusas petenti visa est Stella super ipsam lancem constitisse : and that in Romanorum castris visa sunt ardere pila, ignibus scilicet in ilia delapsis. Caesar, in his history of the African war, says, in a violent stormy night, Legionis pi- lorum cacumina Sua sponte arserunt : and Livy mentions two similar facts. To these may now be added one from Mr. Fynes Moryson, who in his Itinerary, observes, that at the siege of Kingsale by the lord deputy Montjoy, where Mr. Moryson attended him in the camp, on the 23d of December 1601, all the night was clear, with lightning, as in the former nights were great lightnings with thunder, to the astonishment of many, in respect of the season of the year, ' that this night our horsemen set to watch, to their seeming, did see lam^ burn at the points of their staves, or spears, in the midst of these lightning flashes.' LXI. Extract of a Letter of the Rev. Joseph Spence, Prof, of Modern History in the University of Oxford, to Dr. Mead, F.R.S. Dated By fleet near fVey- bridge, Surrey, Decemb. 7, 1733. p. 486. I have lately received a letter from Signor Pademi at Portici ; in which, speak- and at the same time obtained the degree of m. a. from Aberdeen. In 1744 he was presented to the rectory of St. Michael, Wood-street ; and about 2 years after, to that of St. Margaret Fattens. In 1752 he was elected Secretary to the r. s. ; and the next year had the degree of d. d. conferred on him by the Archbishop of Canterbury. In 1761 he was presented to the rectory of Depden in Essex, But in 176(5 he died suddenly by a fall from his horse. Dr. Birch was moderately learned, and of rather slow parts; but he was an exceedingly industri- ous and indefatigable compiler, and a very useful secretary to the r.s. He had a considerable share in compiling the General Dictionary, historical and critical, 10 vols, folio : and he published the lives of Mr. Boyle, Archbishop Tillotson, Henry Prince of Wales, and other works of a similar kind. He also wrote an Inquiry into the Share which Charles the 1st had in the Transactions of the earl of Gla- morgan, 8vo, 1747. But by far his most useful work, was the History of the Royal Society, in 4 vols. 4to, 1756, &c. This work he was enabled to compile by his situation of Secretary to the r. s., which gave him access to the archives of that learned body, whence he extracted and published what may be deemed the real Transactions of the Society, being the minutes and records from the books kept by the committee, by whom all the real business of the Society is, or ought to be, conducted. Thus we have in this work a curious and useful detail of the Society's concerns, from the beginning of the institution to the end of the year l687 ; and probably would have been continued to his own time had his life been longer spared. And it would be a most useful and meritorious service, if that curious work were continued to the present times, by some other secretary of the Society ; for no person can execute that task, but such as can have access to the minute books of the committee. Dr. B. bequeathed his books, Mss., and a legacy of sSoOO to ihe British Museum, the money to go towards increasing the stipend of the two assistant librarians. 448 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. ing of the publication of the antiquities found at Herculaneum, he says, Spero che il primo tomo non tarder^ molto tempo ad uscire ; and then mentions some particular things that had been lately discovered among the ruins ; a little brass bust of some unknown philosopher, of the manner excellent, and is perfectly well preserved : a statue of an orator, in marble ; and another brass bust, on a term, of a youth, with very beautiful hair, and the whole excellent. The artist has put his name to the latter, AnOAAilNIOI APXIOT AQHNAIOi; EnoiHIE. He says, that the workmen were then just entering on some nobleman's house, as appeared by the rich Mosaic pavements, &c. and that they were in hopes it would prove a very good new mine. LJCII. On the Value ofanAnnuilyforLife, and the Probability of Survivor- ship. By Mr. James Dodson. p. 487. • The writers on the subject of annuities on lives have justly distinguished them into 2 kinds : in the first, the annuitant is entitled to receive a payment, if he be alive on the day on which it becomes due ; but if he dies on the preceding day, or sooner, his heirs have no claim to any part of the payment, so to have become due ; but in the second, if the annuitant dies at any intermediate time between the days of payment, his heirs are to receive a part of the annuity, pro- portional to the time elapsed between the preceding day of payment and the an- nuitant's decease. This latter kind of annuities have been distinguished from the former, by the words, secured by a grant of lands ; because, where lands are leased for lives, the conditions are generally such as are above described. The values of the first kind of annuities have been investigated on principles purely arithmetical ; but in order to perform the latter, fluxions have been used, Mr. D. conceives, without any necessity : but as the investigation of the former may be usefully made a part of the latter, he first recites the method of perform- ing that, and then proceeds to attempt the other on the same principles. If, with De Moivre, we suppose the decrements of life to be equal (viz. that out of a number of persons, alive at a given age, equal to the number of years that a person of that age has a possibility of living, there will die one in each year, till they are all extinct) ; then, out of a number of chances equal to that number of persons, which may, for instance, be 36, all but one are favourable, in the first year, to any individual ; and consequently it is 35 to 1 that he receives one payment of the annuity, by living till it becomes due ; that is, the probability of his receiving it, is -§4, and of not receiving it, ^V- Again ; since, by supposition, there dies but 1 person in the first year, and 1 in the lA ; there are but 1 chances, in the 36, against his receiving the 2d pay- ment, by living till it becomes due ; and consequently f-i will be the probability of his receiving that also ; the probability of his dying in that year being -j?^-, as VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 449 before. Thus too it may be proved, that the probability of his receiving the 3d, 4th, 5th, &c. payment, will be 4-|-, f|-, -§-^, &c. and therefore, if the annual payments were each ll. and if the interest of money was not to be considered, we might conceive these several probabilities, as the present worths of the several payments, and the sum of them would be the value of an annuity of the first kind. But since the interest of money necessarily enters the process, and since the payments become due at the end of the 1st, 2d, 3d, &c. year, the first of these payments must be discounted for 1 year, the 2d for 2 years, the 3d for 3 years,. &c. and the sum of their present worths will be the value of an annuity of the first kind, to continue during the life of a person who may possibly live 36 years ; and this sum may be found by an easy and well-known process, from the common tables of compound interest and annuities, which need not be inserted here. The annuity secured by land must necessarily be of greater value than the above; because, though the annuitant dies before the payment becomes due, yet his heirs are to receive a part of it ; the atniuitant therefore, in this case, has not only the probability 4-^ of receiving the first payment, but he has also an ex- pectation on part of the probability -^y which in the first case was wholly against him. Now it may be esteemed an equal chance, supposing him to die in the first year, whether that decease happens before the expiration of half that year, or after it ; and if it happens before, he is to receive less than half the annual payment ; but if after it, more. The annuitant may therefore be supposed to have an equal chance, if he fails of receiving the whole first payment, yet of receiving half of it; and consequently half of the probability, ^, which was before totally against him, will in this case be favourable to him ; and his expectation of receiving either the whole, or at least half of the first payment, will be -y- + ^. So since the probability of his dying in the 2d year, is also -3-'^; we may in the same manner prove, that one half of it will in this case become favourable to him ; and consequently that ■§-|- -j- ^ will be the probability of his receiving the whole, or at least half, of the 2d payment. It appears therefore that for every year which he has the pos- sibility of living, he will in this case have the probability y^, or half of ^, in his fevour, more than he had in the former case; and therefore, if the present worths of the constant sum ^vl- (supposed to be due at the end of 1, 2, 3, &c. years) be found, and added to the value of the annuity, according to the former case, the sum will be the value of an annuity, secured by land, to continue during the life of a person who may possibly live 36 years. Now since the sums by which the former annuity is to be increased, consist of the present worths of that fraction of a pound sterling, whose numerator is unity, and denominator twice the number of years that the annuitant can pos- VOL. X. 3 M 450 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754.. sibly live, supposed to be due at the end of each of ] , 2, 3, &c. years ; it will follow that their amount, or the difference between the values of the 1 annuities, will be equal to the quotient found by dividing the value of an anuity of ll. certain, for as many years as the annuitant can possibly live, by twice that num- ber of years : and therefore, if to the value of an annuity for life, of the first kind, we add the quotient so found, the sum will be the value of an annuity of the second kind, for the same life. When Mr. D. had thus investigated the value of this annuity, he compared the result with that M. de Moivre had deduced from fluxions, and published in N" 473 of the Phil. Trans.; and found that they agree to more than a sufficient exactness, for computations of this nature. He then annexes this comparison. The probability of any order of survivorship, that can happen among 3 per- sons, and consequently that of one person's surviving 2 others, may likewise be investigated on similar principles, without the assistance of fluxions ; but as this problem admits of 6 cases, and the algebraic process is of a length too great for the designed limits of this essay, Mr. D. omits it. LXITI. On the Pheasant of Pennsylvania,* and the Otis Minor. By Mr. George Edwards. •\- p. 499. What is called the pheasant in Pennsylvania, and other provinces of North America, belongs to that genus of birds, which in England we call heathcocks, * This bird is the Tetrao Umbellm of Linneus, and is extremely well figured iti the 1st volume of Edwards's Gleanings of Natural History, pi. 248. t From the Memoirs of his Life, published in 1776, it appears that Mr. George Edwards was bom at Stratford, a hamlet belonging to Westham in Essex, on the 3d of April 1694. He passed some of his early years under the tuition of a clergyman named Hewit, who was then master of a public school at Layton-Stone, a few miles distant from the village where he was born. After quitting the school he was placed with another minister of the established church at Brentwood; and being designed by his parents for business, was put apprentice to a tradesman in Fenchurch-street. On the expiration however of his apprenticeship, he declined entering into business, and conceived a design of travelling, in order to improve his taste, and enlarge his mind. He first visited Holland and afterwards Norway, and having gratified his curiosity with the view of these regions, returned and passed some time in his native place. He then went to France, where, on visiting Versailles he experienced great disappointment at finding that the Menagerie, once so celebrated, had at that time no living creature in it, having been totally neglected since the death of Louis the 14th. On his return to England Mr. Edwards closely pursued his favourite study of Natural History, employing himself in making drawings of such animals as happened to fall under his notice; and the accuracy and elegance of his delineations was such as to make them highly interesting to those who cultivated similar pursuits. He therefore was induced to turn to advantage what was begun only for amuse- ment, and obtained a sufficient subsistence by the sale of his drawings. In December 1733, by the recommendation of Sir Hans Sloane, he was chosen librarian of the College of Physicians ; an office peculiarly suited to his taste, as it gave him constant access to many works on the subject of Natural History, which he might otherwise have found a difficulty of inspecting. In 1743 the first volume VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 451 moor-game, or grouse. It is nearly as large as a pheasant, is of a brownish colour on the head and upper side, and white on the breast and belly ; it is beau- tifully variegated with lighter and darker colours on the back, and spots of black on the under side. Its legs are feathered down to the feet. This bird is wholly unknown to the curious of our country. It was sent to England, a year or two ago, by Mr. John Bartram, with a letter giving some account of it, and other matters ; out of which letter is extracted what follows : ' our pheasant was wholly unknown to Catesby, it being more northern than Carolina. They have been common in Pennsylvania, but now most of them are destroyed in the lower set- tlements, though the back Indian inhabitants bring them to market. When living, they erect their tails like turkey-cocks, and raise a ring of feathers round their necks, and walk very stately, making a noise a little like a turkey, when the hunter should fire. They thump in a very remarkable manner, by clapping their wings against their sides, as is supposed, standing on a fallen tree. They begin their strokes at about 2 seconds of time distant from each other, and re- peat them quicker and quicker, till they sound like thunder at a distance, which lasts about a minute, then ceases for 6 or 8 minutes, and begins again. They may be heard near half a mile, by which the hunters find them. They exercise their thumping in a morning and evening in the spring and fid! of the year. Their food is berries and seeds. Their flesh is white, and good. I believe they breed but once a year in the spring, and hatch 12 or 14 at a sitting ; and these of his History of Birds was published ; the reception of which was so highly favourable as to induce him to continue it in a similar manner, till in 1751 the fourth volume came from the press, accom- panied by a dedication to the Creator of the universe, in devout gratitude for all the good things he received in this world. In 1758 he continued his labours under a new title, viz. Gleanings of Natural History, containint^, as before, various kinds of rare birds, quadrupeds, and other animals : a 2d volume appeared in 1760, and the 3d and last in 1764. The whole work therefore consists of seven volumes in 4to, containing engravings and descriptions of no less than 6OO subjects in Natural History. To the work, thus com- pleted, Linneus added a list of his own trivial names. Linneus indeed appears to have entertained a very high esteem for Mr. Edwards, and to have considered his work as of the highest importance in Natural History, and, in the Systema Naturae, publicly declares its superiority over other production* of a similar kind. By the time Mr. Edwards had finished his Natural History, the decay of his sight, together with other infirmities of age, induced him to resign all further employment, and to retire to a small house which he purchased at Plaistow, Essex, where he continued to pass the remainder of his life, and died on the ^23d of July, 1773, having completed the 80th year of his age. Mr. Edwards, we are informed, was of middle stature, rather inclined to corpulence ; of a liberal disposition and a cheerful conversation. All his acquaintance experienced his benevolent temper, and his poor neighbours frequently partodk of his bounty. In consequence of the merits of his publications in Natural History, Mr. Edwards was elected a r.ii.s. He was also a f.a.s., as well as a member of several Academies in different parts of Europe. 3 M '2 45'2 PHILOSOPHICAL TRANSACTIONS. [anNO 1754. keep together till the following spring. They cannot be made tame. Many have, to their disappointment, attempted it by raising them under hens; but, as soon as hatched, they escaped into the woods, where they either provide for themselves, or perish.' Mr. Brooke, surgeon of Maryland, says, ' They breed in all parts of Mary- land, except near the eastern shores. They lay their eggs in nests made of dry leaves by the side of a fallen tree, or at the root of a standing one; they lay from 1 2 to 1 6 eggs, and hatch in the spring. I have found their nests, when I was a boy, and have endeavoured to take the old one, but never could: she would let me put my hand almost on her before she quitted her nest; then she would flutter just before me for 100 yards, or more, to draw me off from her nest, which could not afterwards be easily found. The young ones leave the nest as soon as hatched, and, I believe, live at first on ants and worms; when they are a few days old, they hide themselves among the leaves, that it is hard to find them. When they are grown up, they feed on the berries, fruits, and grain, of the country. Though the pheasant hatches many young at a sitting, and often sits twice a year, the great number and variety of hawks among us, feeding on them, prevents their increasing fast. The beating of the pheasant, as we term it, is a noise chiefly made in the spring by the cock birds. It may be distinctly heard a mile in calm weather. They swell their breasts like a pouting pigeon, and beat with their wings, which sounds not unlike a drum. They shorten each sound in a stroke, till they run into one another undistinguished.' Lahontan, in his voyage to North America, vol. i, p. 67, speaking of the fowls about the lakes of Canada, mentions this same pheasant as follows: " Their flapping makes a noise like a drum, all about, for the space of a minute; then the noise ceases for half a quarter of an hour, after which it begins again. By this noise we were directed to the place, where the unfortunate moor-hens sat, and found them on rotten mossy trees. By flapping one wing against the other, they mean to call their mates, and the humming noise, thus made, may be heard a quarter of a league off. This they do only in the months of April, May, September, and October; and, which is very remarkable, a moor-hen never flaps in this manner but on one tree. It begins at break of day, and gives over at 9 in the morning, beginning again an hour before sun-set, and flaps its wings till night." This is all tlie light I could gather, relating to the pheasant of North America. The Otis minor,* anas campestris, canne petiere, or the field-duck, was taken in the west of England, and laid before the Royal Society about 3 years ago: and as no gentleman present knew the bird, Mr. Hauksbee sent it to Mr. E. • This bird is the otis tetrax of Linneus, and is figured in the first volume of Edwards's Glean- ings, pi. 251. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 453 who accordingly gave in what account of it he could collect from ornithologists, having never seen the bird till then. He found figures of it in Bellon, Gesner, Aldrovand, Willoughby, Johnson, and others, with descriptions under the various names here given. Modern authors agree that this bird was unknown to the ancients. LXIF. On a Particular Species of Coralline. By Mr. J. Ellis, F.R.S. p. 504. Among the observations lately made on the marine productions, Mr. E. finds that many corallines, as well as corals, are composed of a great number of tubes, which proceed from animals; and as these tubes are made of different materials in different species, so are they disposed in a variety of different forms. Some are united compactly together, as in the red coral, see pi. 10, letter A; and in some species of the white, as at letter b ; in both of which they appear com- bined together, forming irregular ramifications, like trees: others rise in tufts, like groupes of the tubular stalks of plants, distinct from each other. Two sorts of these the fishermen frequently take up at sea in their nets, particularly near the buoy of the Nore, at the opening of the river Thames ; when these are first taken out of the sea, and immediately put into a basin of sea-water, you may observe, that each tube has its proper polype sitting on it, of a most beautiful crimson colour. Letter d,* gives the figure of the largest kind, called (in Ray's Synopsis, ed. 3, p. 31) adianti aurei minimi facie planta marina; and letter c is a smaller kind, called (in Ray's Synopsis, ed. 3, p. 39) fucus dea- lensis fistulosus laringae similis. He calls this species corallina tubularia meli- tensis, cum scolopendris suis, tentaculis duobus duplicato-pinnatis, instructis.-|- On taking the tubes and animals of this curious Maltese coralline out of the spirits of wine, where they had been preserved, he perceived a small slimy bag, in which they seemed to be inserted, and to take their rise from, as may be ob- served at letter d. What has been the use of this bag is uncertain, unless it was the matrix of several of these scolopendras in their embryo state. The tubes, which are built by the inclosed animals, as they rise in height, gently increase in diameter; the texture of their outside coat is formed of an ash-coloured earthy matter, of different shades in different strata, and closely united to an inner coat, which is of a tough, horny, transparent, and very smooth substance ; the cavity, or inside, of the tube, is perfectly round, though the animal is of a long com- pressed figure, like a leech extended It appears, from the marks of its feet on • The species referred to at letter d is the tubularia incUvisa of Linneus. That referred to at letter c is the tubularia muscoides, Linn. t This is the sabella penicillus of Linneus. It is however more properly referred to the genus amphitnte, and is the amjihilrite ventHabntm of the Gnnelinian edition of the Systema Naturae. 454 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. the inside of the tube, that it can turn itself freely about, and move up and down, the better to attack and secure its prey. This scolopendra has two very curious and remarkable tentacula, or arms, the left much larger than the right; these are doubly feathered, as may be seen, in the magnified part, at c ; the number of feet on each side of the botly of this animal exceeds 150. Plate 10, will best explain the rest; where b is the belly part of the animal, in its natural size, hanging out of its tube, i is the same side of the whole animal a little magnified, a is the back part of the head of the animal, sitting in its tube, h is the back part of the whole animal a little magnified, e shows the inside of the tube with the strata, or rings, seen through the horny inner coat. The coralline called (in Ray's Synops. ed. 2, p. 2, and ed. 3, p. 36, N° 15) fruticulus marinus, cauliculis crassiusculis teretibus rigidis, pennatus,* which I have named the herring-bone coralline, and which is very common on oysters all the winter season, shows remarkably, by the help of a common magnifying glass, the tubulary structure, not only of some of the corals and corallines, but of the keratophytons, or sea feather; only with this difference, that the tubes of the herring-bone coralline are of a spongy elastic nature, and always remain open; whereas the others, being of a more soft and viscid nature, by time, and the heat of the climate, are compressed together, and harden, some into stone, and some into horn or wood. At E is the natural appearance of the herring-bone coralline; and f and g the root, and one of the upper branches, are magnified, to show the tubes. LXJ^. Observations on the late severe Cold Weather. By William Arderoii, F.R.S. p. 507. The observations were taken by thermometers exposed to the open air, in the garden, which varied sometimes 40 or 50 degrees in 24 hours; the cold coming as it were by fits, in an unusual manner. Dec. 30, at 1 1 o'clock at night. — All the spirits in Hauksbee's thermometer retired into the ball, and Fahrenheit's stood at 20 degrees: at this time he let down a Fahrenheit's thermometer into the river, to the depth of 4 feet, during 12 minutes, and when taken up it stood at 33 degrees. This same evening he exposed an open glass jar full of water, in the garden, to be frozen; and in the morning it was all solid ice, rising in the middle, in fi- gure like the frustum of a cone. He exposed also, in the same place, an open glass of ale, which froze even to the bottom, in a very odd manner; for the • Sertularia haUcina. Linn. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 455 watery or weaker parts were frozen into plates of ice, sticking to each other by their edges, the more spirituous parts remaining between them, in their inter- stices, unfrozen ; which being drained off into another glass, the taste was almost as strong as brandy, with a high flavour of the hop. Dec. 3 1 . This evening the cold was the most intense observed this season ; for at 10 o'clock Fahrenheit's thermometer stood at 15 degrees. Jan. 1. This afternoon it began to thaw, and in the night froze again, by which, next morning, the buildings in general appeared as if they had been white-washed on the outside, being cased all over with ice; and the insides of garrets and outhouses were covered in the same manner. Jan. 31, He exposed a glass of proof spirits, impregnated with the essence, or oil extracted from the peel of oranges, at 10 in the evening, in the garden, when Hauksbee's thermometer stood at g3°; at 8 next morning, he found it no way affected by the frost ; nor did there seem any difference either in taste or smell. Feb. 6. At 8 o'clock, he exposed in the garden a drinking glass of water, which was completely frozen over in one minute's time ; and in 1 5 minutes the ice was above -^ of an inch in thickness. Fahrenheit's thermometer then stood at 21 degrees. A coarse grey thread, 2 feet in length, being dipped in water, froze in 4 seconds, so stiff, that he took it by one end, and held it upright, as if it had been a piece of wire. If any part of the human skin, the finger, for instance, was wet with spittle, and immediately pressed on a piece of iron, in the open air, it would be frozen so fast, as to stick to it; and, if plucked away hastily, would endanger the tear- ing off the skin from the flesh. He tried the same experiment on lead, but the sticking was much less; and to wood the finger did not stick at all. In some places the ice was -i- of an inch thick, for several days together, within-side of the windows, and that even in rooms where fire was kept; and when the weather became warmer, it did not fall in drops, but vanished imperceptibly into the air, by which it had been brought thither. These plates or cases of ice were sometimes an assemblage of an infinite number of particles not much unlike the scales of fishes; sometimes they resembled small spines, or the crystal shootings of various kinds of salts ; and sometimes they represented a variety of landscapes with trees and plants, from 1 to 3 or 4 inches in length, in so beautiful a manner, as nei- ther pen nor pencil can express. LXFI. A Letler from M. de Ulsle, of the Royal Academy of Sciences at Paris, to the Rev. James Bradley, D.D. Dated Paris, Nov. 30, 1752. Translated fro7n the French, p. 312. This letter contains a comparison of Dr. Bradley's observations of the planet Mars, with some corresponding observations made at the Cape of Good Hope 456 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. by Mens, de la Caille; from which he concludes, that the horizontal parallax of that planet, at the time of its opposition to the sun, is 1T\". And according to the ratio of the distance of the sun and Mars from the earth at that time, he concluded the horizontal parallax of the sun to be about 10^". This is what he had been able to conclude from Dr. B.'s observations of Mars, with respect to the parallax of the sun. Having made the same calculations from his own observations, and those of other astronomers, which he could col- lect; he found very nearly the same parallax of the sun, by taking a medium among all the observations of each astronomer, ^LXVIL Description of a Piece oj" Mechanism contrived by James Ferguson, for exhibiting the Time, Duration, and Quantity, of Solar Eclipses, in all Places of the Earth, p. 520. This machine may be seen described in Mr. Ferguson's Astronomy, art. 405, where he calls the machine an eclipsareon, the figure of which is exhibited in pi. ] 3 of that book. LXFIII. On the late Hard Weather. By the Rev. H. Miles, D. D., F. R. S. p. 525. This paper contains a few remarks on the very cold weather in Feb, 1754. The coldest day was on the 6th, about 7 in the morning, when the thermometer was at 15°. He observes that the time of the greatest cold, is usually from an hour to an hour and a half before sun-rise. LXIX. A Catalogue of the 50 Plants from Chelsea Garden, presented to the Royal Society by the Company of Apothecaries, for the Year 1753, pursuant to the Direction of Sir Hans Sloane. p. 528. This is the 32d presentation of this kind, completing to the number of l6oo different plants. LXX. An Account of some Experiments on a Machine for Measuring the Way of a Ship at Sea. By Mr. J. Smeaton, F. R. S. p. 532. In the Philos. Trans. N° 39 1 , Mr. Henry de Saumarez gives an account of a machine for measuring a ship's way more exactly than by the log. This machine consists of a first mover, in the form of the letter y. On the 2 arms of the Y are fastened 2 vanes, inclined in such a manner that when the y is hauled through the water by a rope, fastened to its stem or tail, it may turn round, and of consequence endeavour to turn the rope round. The other end of the rope, being fastened to the end of a spindle capable of moving freely round, will be made to do so by the rotations of the y, communicated to the rope. A motion VOL. XLVIIi:j PHILOSOPHICAL TRANSACTIONS. 457 being thus cominunicated to a spindle within the ship, this spindle may be made to drive a set of wheel-work, which will register the turns of the y ; and the value of a certain number of these turns being once found, by proper experi- ments, they are easily reducible into leagues and degrees, &c. The only diffi- culty then is, whether this y will make the same number of rotations in going the same space, when it is carried through the water fast, as when it is carried slow. On this head Mr. de Saumarez, as well in the paper above-cited, as in a subsequent one published in Philos. Trans. N° 408, has given an account of several trials, which he has made of it, from which it appears, that this machine in part answers the end proposed, and is in part defective; the errors of which he supposes to proceed from the sinking down of the y into the water on a slow motion ; the axis of its rotation being then more oblique to the horizon, than in a quick one. In a machine constructed like this, it is evident that the end of the spindle, to which the rope is fastened, must be of sufficient strength and thickness, not only to bear the force or stress, that the hauling of the y through the water will lay on it, in the greatest motion of a ship; but also to bear the accidental jerks of the waves. The thickness of the spindle then being determined by these con- ditions; it is also manifest, that to prevent the spindle from being pulled out of its place by the draft of the rope, there must be a shoulder formed on it, which must be greater than the part of the spindle before described, for the spindle to bear against. The size that Mr. Saumarez proposes to give to his y, is 1^ inches tfie whole length; 15 inches for the length of the arms, which are to be opened to a right angle; 8 inches for the length of each vane; A\ inches broad, and^ the stems and shank to be \ of an inch thick. According to these dimensions, the resistance that this part of the machine will meet with, in passing through the water, will, in the swift motions of the ship, be very considerable; conse- quently the necessary bulk of the pivot-end of the spindle, and its shoulder, will occasion a considerable friction in its turning, and retardation to the rotation of the machine. To cure these defects, as much as possible, instead of the y before described, Mr. S. made trial of a single plate of brass, of about 10 inches long, 2-J- broad, -^ of an inch thick, and cut into an oval shape. This plate being set a little atwist, and fastened by one end to a small cord, in the manner of the y, is like- wise capable of making a rotation, in being drawn through the water; but with this diffiirence, that as this is but a small thin plate drawn edgewise through the water, its resistance, in passing through it, is much less; of consequence, a much smaller line is sufficient to hold it, which again considerably diminishes the resistance; and this of course proves a double diminution of friction in the spindle; first, as the pressure upon it is less; and, secondly, as it allows the VOL. X. 3 N 438 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. spindle aiul shoulder to be of a less diameter. To break the jerks of the waves, next to the end of the spindle he fixed a spiral spring of wire, to which the cord was fastened; which, by this means, was capable of playing backwards and for- wards, and giving way to the irregularities of the sea: and lest the plate should lay fast hold of any thing, or any extraordinary jerk should damage the spindle or spring, a knob or button was fastened on the cord, at a small distance from the spring, which stopped on a hole in a piece of wood, and prevented the spring from being pulled out to above a certain length ; so that all addition of force, beyond this, could only tend to break the cord, and carry away the plate. The spindle, being thus guarded from accidents, will allow of a still further diminution of its size; so that, at last, he ventured to make the spindle-pivot no more than -jV of an inch diameter, and that of the shoulder J-, being of tempered steel, and sufficiently smooth. The hole, in which the pivot, and against which the shoulder worked, was of agate likewise, well polished. Being thus provided, in May 1751} he procured a boat, on the serpentine river in Hyde-park, to try how far the turns of the machine would be consistent with themselves, when the same space was measured over with different velocities. The course was determined at each end, by observing the coincidence of two trees, in a line nearly at right angles to the river. We however rowed beyond the mark, that the machine might be in full play when the course was begun: the spindle was stopped at the beginning and end; the numbers read off were as follow : The space between the marks was, by estimation, about half a mile. 1st rowing up the river, in 11 min. the plate made 6l5 revol. 2d down 14 645 3d up 18i 6l2 4th down Q-J- 603 5th up 18 620 6th down 10 600 It is observable, that the greatest difference among the above observations, is between the 2d and 6th, being 645 and 60O; the difference being about a 4th part of the whole; the times being 14 minutes and 10, both in going down the river; whereas those observations, which differ most in point of time, viz. the 3d and 4th, being performed in I8-1- minutes, and 9-r minutes, have their revo- lutions more nearly alike, being 6l2 and 603; which differ only by a 68th of the whole. From these observations he was led to think, that the different ve- locities, with which a vessel moves forwards, would make no material difference in the number of rotations of the plate; or at least that those differences would be less than the irregularities arising from other causes, even in trials nearly similar. VOL. XLVIII.^ PHILOSOPHICAL TRANSACTIONS. 459 The next trial of this machine was on board a small sailing vessel, in company with Dr. Knight, and Mr. William Hutchinson, an experienced seaman. The expedition was on the river Thames, and some leagues below the Nore. The intention of the trial here, was to find in general, how far it agreed with the log, and how it would behave in the swell of the sea; a comparison with the measure of a real distance being here impracticable, on account of the tides and currents. The method of trial was this: the whole log-line was suffered to run out, being 357 feet between the first knot and the end. The person who hove the log gave notice, at the extremes of this measure, that the person who at- tended the dial of the machine might stop the spindle at the beginning and end; while a third observed, by a second's-watch, the time taken up in running these 357 feet. By these means, we were enabled to ascertain the comparative velocity moved, and the number of turns of the plate at each trial, corresponding to 357 feet by the log ; which, if the machine and log were both accurate, ought to have been always the same. The particulars of these experiments are contained in the following table. Turns of the Seconds of time during the run- Turns of the Seconds of time during the run- pUte. ning out of 357 feet oflog-line. plate. ningoutofss? feetof loj-line 83 In the river at anchor by the tidel24 70 Before the wind at sea .... 56 82 The sarae rei)eated 134 70 The same 52 81 Sailing in the river 98 66" Before the wind in the river 55 79 In the river at anchor by the tidel35 6i The same 53 76 Sailing in the river 115 64 The same 60 74 At sea upon a wind 64 64 The sarae 43 74 The same repeated ... 69 63 At sea upon a wind 53 71 Sailing in the river 71 62 The same ....•• 52 70 The same 66 62 Sailing in the river 45 70 Before the wind at sea 77 It appears from these trials, made in diflferent positions of the vessel with regard to the wind, both in the river and at sea, as well by the tides at anchor, as in sailing, that the turns of the plate corresponding with the space of 357 feet by the log, were from 62 to 83 ; and the times in which this space was run, were from 45 to 135 seconds, the greater number of revolutions answering to the greater number of seconds, or slower movement of the vessel. On finding this considerable disagreement between the log and plate, when swift and slow mo- tions are compared, Mr. S. did not suppose that they proceeded from a retarda- tion of the plate in swift motions, but from the hauling home of the log in slow ones. For instance, the log, to do its office accurately, ought to remain at rest in the water, whatever be the motion of the vessel. But even the keeping the line straight, and much more the suffering the log to haul the line off the reel, as practised by many, will make the log in some measure follow the vessel, and 3 N 2 4()0 PHILOSOPHICAL TRANSACTIONS. [aNNO J 754. will be greater in proportion as the time of continuance of this action is greater; and therefore the log will follow the ship twice as far in going one knot, when the ship is twice as long in running it. The consequence of this is, that a vessel always runs over a greater space than is shown by the log-line ; but that this error is greater, in [)roportion as the vessel moves slower. It is this reason probably that has induced the practical seamen to continue the distance between their knots shorter than they are directed by the theory. Afterwards, in the same summer, Mr. S. made such another expedition, in a sailing vessel, along with Capt. Campbell of the Mary yacht, and Dr. Knight. Having prepared two of these machines as near alike as possible, he determined to try, how far they were capable of agreement, when exposed to the same in conveniencies, and used together. During the trial of these machines, one made 86,716 revolutions, and the other made 88,184. During this space, they were compared at 10 several intervals. The revolutions between each interval differed from the proportion of these numbers, in the first comparison, -rV of the whole interval. The errors of each interval, in the other comparisons, were, in order, vVj tVj -sV) Vt, tt, ^, tt> -tt, tV; the greatest errors being where the spaces were the shortest. In other respects, the plates seemed to perform their duty in the water well enough, though the sea was as rough in this voyage as our small vessel could well bear. Lastly, being for some time on board the Fortune sloop of war, commanded by Alexander Campbell, Esq. in company with Dr. Knight, for the purpose of making trial of his new invented sea-compasses, I had frequent opportunities of making use of these machines, by comparing them with each other, with the log, and with real distances; and having, by repeated trials, pretty well ascer- tained the number of turns of the plate, equal to a given space, by the help of the log, in the manner before described, when the ship was on a middle velocity, he found the spaces, so measured, nearly consistent with themselves, and with the truth; but all this while the winds and weather were very moderate. It afterwards happened, that they ran 18 leagues in a brisk gale of wind, which drove them sometimes at the rate of 8 knots an hour, as appeared by heaving the log. During this run he observed, that the resistance of the water to the line and plate, was very considerable, and increased the friction of the spindle so much, as to prevent it from beginning to turn, till the plate had twisted the line to such a degree, that when it did set a-going, it would frequently run 150 or 200 turns at once. He also observed, that the wind coming across the course of the ship, blew the cord a good deal out of the direction of the spindle, and caused the line to i-ub against the safeguard hole, for the button to stop against, as above described; which undoubtedly occasioned considerable friction in that place. But the most untoward circumstance was, that being in a rough, but TOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 46I short chopping sea, and sailing obliquely across the waves, the plate would fre- quently be drawn from one wave to another through the air, without touching the water; and would jump from one wave to another; the unevenness of the surface, joined to the quickness of the motion, not permitting the plate to follow the depression of the water. This evil he endeavoured to remedy, by placing on the line, at a small distance before the plate, some hollow bullets, such as are made for nets, in order to keep the plate so low down in the water, as to be below the bottom of the waves. This, in part, he found they did; but at the same time they added so much resistance, in their passing through the water, that the inconvenience was as great one way as the other. On making up the account of this run, the number of rotations were less, by full one-third, than they ought to have been, compared with former observations, which afforded a convincing proof, that this instrument was considerably retarded in quick motions. The length of the line made use of was about 20 fathoms, which he found necessary, that the water, disturbed by the body of the ship, might be tolerably settled before the plate was drawn through it ; but this length of line was also an inconvenience, as it met with greater resistance in the water. On the whole, it seemed that such an instrument is capable of measuring the way of a ship at sea, when its velocity does not exceed 5 sea miles an hour, to a degree of exactness exceeding the log. It therefore may be useful in the mensu- ration of the velocities of tides, currents, &c. and also in measuring distances at sea in taking surveys of coasts, harbours, &c. Thus far it seems capable of performing, on the supposition that it cannot be brought to a greater degree of perfection. But this he was very far from supposing: on the contrary, he thinks that it may be brought to answer the end of measuring the way of a ship at sea universally. LXXI. Observations of some Eclipses of Jupiter s Satellites at Lisbon in 1753. By J. Chevalier, p. 546. LXXII. Observation of a Solar Eclipse at Lisbon, Oct.^Q, 1753. By J. Chevalier, p. 546. An account of the above two articles is contained in the following. LXXIIL An Account of some Astronomical Observations taken at Lisbon by M. J. Chevalier in the Year 1753. By J. Short, M.A., F.R.S. p. 548. This gentleman mentions two emersions of the satellites of Jupiter, viz. one of the first, and another of the third, both observed, in a very clear air, with a Gregorian telescope 6 feet long. Dr. Bevis, from a great number of observations, has computed formulae of tables for the times of the immersions and emersions 462 PHILOSOPHICAL TRANSACTIONS. ' [aNNO J 754. of the first satellite of Jupiter, and which times we have seldom found to differ from the observations above lO': by comparing therefore the time of the emer- sion of the first satellite observed by this gentleman, with the time computed from these formulae, the difference of longitude between London, at St. Paul's, and the place of observation at Lisbon, comes out to be 36"" 6^ ; and by several former corresponding observations the difference had been found to be 36™ lO'. M. Chevalier further mentions the observation of the eclipse of the sun last October, through a telescope of 1 5 palms. He saw both the beginning and end, in a very clear air ; and says that the greatest quantity of the eclipse was 1 1 digits and 5', which he measured with a micrometer ; but unluckily he has not given us either the diameter of the sun, or that of the moon, which he might have measured, (for the eclipse was annular) though he was at the pains of mea- suring all the digits, both in the increase and decrease of the eclipse. He further takes notice, that at the time of the greatest obscuration, the light of the sun was remarkably diminished ; and that they were able to see Jupiter, Venus, and some stars of the first and 2d magnitude ; but he could not see Mercury, on account of his proximity to the sun : and that a reflecting speculum, of 3 palms in diameter, which could melt lead, when placed in its focus, and instantly set wood in a flame, produced the same effects, even when the sun was 7 digits eclipsed ; but that, about the time of the greatest obscuration it was not able to burn wood, though held in its focus for some time : and that at the same time the air became very cold, the wind blowing hard from the north ; and that some vapours, or fog, were seen to rise out of the river and adjacent harbour. LXXIf^. Of an Instrument for Measuring Small Angles, the first Account of which was read before the Royal Society, May 10, 1733. By Mr. John Dollond. Dated April A, 1754. p. 551. Before entering on particulars relating to this micrometer, it will be proper to make a few preparatory observations on the nature of spherical glasses, so far as may be necessary to render the following explanation more easily understood. Obs. 1 . — It is a property of all convex spherical glasses, to refract the rays of light which are transmitted through them, in such a manner, as to collect all those that proceed diverging from any one point of a luminous object, to some other point ; whose distance from the glass depends chiefly on its convexity, and the distance of the object from it. Obs. 2. — The point where the rays are thus collected, may be considered as the image of that point from which they diverge. For if we conceive several radiant points thus emitting rays, which, by the refractive quality of the glass, are made to converge to as many other points ; it will be an easy matter to under- stand how every part of the object will be truly represented. As this property of VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 463 spherical glasses is explained and demonstrated by all the writers on optics, it being the very foundation of the science, the bare mention of it is sufficient for the present purpose. Obs. 3. — It will be necessary however to observe further, that the lines con- necting every point in the object with its corresponding points in the image, do all intersect in a certain point of the axis or line passing through the poles of the glass, where its two surfaces are parallel, and may be properly called its centre. Whence it appears, that the angles subtended by the object and its image, from that point, must be equal : and therefore their diameters will be in the same ratio as their distances from that point. Ohs. 4. — As the formation of the image by the glass depends entirely on the property above mentioned, viz. its collecting all the light, incident on it from the several points of the object, into as many other points at its focus ; it follows, that any segment of such a glass will also form an image equal, and every way similar, to that exhibited by the whole glass ; with this difference only, that it will be so much darker, as the area of the segment is less than that of the whole glass. Obs. 5. — ^The axis of a spherical glass, is a line connecting the centres of the spheres, to which the two surfaces are ground ; and wherever this line passes through the glass, there the surfaces are parallel. But if it happens that this line does not go through the substance of the glass, such a glass is said to have no internal centre ; but it is conceived to be in its plane produced till it meets the axis : and this imaginary point, though external to the glass, is as truly its centre, and is as fixed in its position to it, as if it were actually within its substance. Obs. 6. — If a spherical glass, having its centre or pole near its middle or centre of its circumference, should be divided by a straight line through the middle ; the centre will be in one of the segments only. For how exact soever a person may be supposed to be in cutting it through the centre , yet it is hard to con- ceive how a mathematical point should be divided in two : therefore the centre will be internal to one of the segments, and external to the other. But if a small matter be ground away from the straight edge of each segment, both tlieir centres will become external ; and so they will more easily be brought to a cc incidence. Obs. 7. — If these two segments should be held together, so as to make their centres coincide ; the images, which they give of any object, will likewise coin- cide, and become a single one. This will be the case when their straight edges are joined to make the glass, as it were, whole again: but let the centres be any-how separated, their images will also separate, and each segment will give a separate and distinct image of any object to which they may be exposecl. 464 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. Obs. 8. — ^Though tlie centres of the segments may be drawn from their coin- cidence, by removing the segments in any direction whatever ; yet the most con- venient way for this purpose is, to slide their straight edges one along the other, till they are removed, as the figure in the margin represents them : for thus they may be moved without suffering any false light to come in between them. And by this way of removing them, the distance between their centres may be very conveniently measured, viz. by having a Vernier's division fixed to the brass work, that holds one segment, so as to slide along a scale on the plate to which the other part of the glass is fitted. Obs. Q. — As the images of the same object are separated by the motion of the segments; so those of different objects, or different parts of the same object, may be made to coincide. Suppose the sun, moon, or any planet, to be the object ; their two images may, by this contrivance, be removed till their oppo- site edges are in contact : in which case the distance between the centres of the two images will be equal to the diameter of either ; and so of any other object whatever. Obs. 10. — This divided glass may be used as a micrometer, 3 different ways. In the first place, it may be fixed at the end of a tube, of a suitable length to its focal distance, as an object glass ; the other end of the tube having an eye- glass fitted as usual in astronomical telescopes. 2dly, It may be applied to the end of a tube much shorter than its focal distance, by having another convex glass within the tube, to shorten the focal distance of that which is cut in two. Lastly, it may be applied to the open end of a reflecting telescope ; either of the Newtonian, Gregorian, or Cassegrain construction. And though this last me- thod is much the best, and most convenient, of the three ; yet as the first is the most natural, as well as the easiest to be understood, it will be proper to explain it fully, and to demonstrate the principles on which this micrometer is con- structed, by supposing it made use of in the first way : which being done, the application of it to other methods will be readily understood. Having thus, by the foregoing observations, given a general idea of the nature and effects of this divided object-glass, Mr. D. proceeds to demonstrate the prin- ciples from which the measures of the angles are to be obtained by this instru- ment, by the following propositions. ■ Prop. I. Suppose a divided object-glass fixed at the end of a tube, according to the first method, and the tube directed to the object intended to be measured ; and suppose also the segments removed from their original position, as directed under Obs. 8, till the opposite edges of the two images are seen in contact at the focus of the eye-glass : then the angle subtended by the distance between the VOL. XLVril.] PHILOSOPHICAL TRANSACTIONS. 405 centres of the segments, from the focus of the eye-glass, where the edges are seen in contact, is equal to the angle subtended by the diameter of the object from that same point. Demons. Let the line ab, fig. 7> ph 8, represent the diameter of the object to be measured ; and the points c, d the centres of the two glass segments : also g the focus where the images of the extremities of the object coincide. It is evi- dent, from Obs. 3, that ag and bg are straight lines, that pass through the centres of the segments, and connect the extreme points of the object with their corresponding points in the images; and therefore, as the diameter of the object and the distance between the centres of the segments, are both inscribed between these two lines, they must needs subtend the same angle from the point where those lines meet ; which is at g. The focal distance cg, or dg, is variable, according to the distance of the object from the glass : so that it decreases as the distance of the object from the glass increases ; and when the object is so far off, that the focal length of the glass bears no proportion to its distance, then will it be least of all ; as cf or df; and the point f is called the focus of parallel rays. Any other focus, as g, being the focus of a near object, is called a respective focus ; as it respects a particular distance : but the focus of parallel rays respects all objects that are at a very great distance; such as is that of all the heavenly bodies. Prop. 2. — ^The distance he of the object from the glass, is to ef, the focal distance of parallel rays, as the distance hg of the object from its image, is to EG, the distance of the image from the glass : that is, he : ff :: hg : eg. The demonstration of this proposition may be gathered from any ireatise of dioptrics ; it being a general rule for finding the respective focus to any given distance, when the focus of parallel rays is known. Prop. 3. — ^The angle subtended by the diameter of the object, from the glass, is equal to that subtended by the opening of the centres of the segments, from the focus of parallel rays. That is, the angle aeb equal to the angle cfd. Demons. — It appears, by inspection of the figure, that ab : cd :: hg : eg. And by the last prop, he : ef :: hg : eg. Then, as the two last terms of tliese two analogies are alike ; the two first terms of one will be in the same proportion as the two first terms of the other ; which gives the following proportion : ab : CD :: HE : ef. Whence the truth of the proposition is evident. From this proposition it appears, that the angle subtended by the diameter of the object from the glass, is found without any regard to the distance of the object, or to the distance of the respective focus, where the image is seen ; as the measure depends entirely on the focus of parallel rays, and the opening of the segments. We may hence also derive a rule for the quantity of the angle, without considering the length of the glass. Let an object, whose diameter is VOL. X. 3 O 466 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. known, be set up at some known distance ; the angle it will subtend from the glass may then be found by trigonometry : then let it be measured by this mi- crometer, and the distance between the centres of the segments, found on the scale already mentioned, will be the constant measure of the same angle, in all other cases ; because the distance of the object makes no alteration in the mea- sure of the angle, as has been demonstrated : and thus having obtained the dis- tance between the centres of the segments, which answers to any one angle, all other distances may be computed by the rule of three. All that has been hitherto said relates to the first method of using this micro- meter ; that is, by fitting it to the end of a tube suited to its focal length, and by viewing the images with a proper eye-glass, in the manner of an astronomi- cal telescope. But the length of the tube, in this way, would be very trouble- some ; and therefore it will be proper to consider other methods for an easier management. He therefore proceeds to the 2d method, mentioned in Obs. 10, which is, by using another object-glass to shorten the focus of that which serves for the micrometer. To facilitate the understanding of this method, it will be necessary to premise the following observation. Obs. 1 1. — Rays of light, which are brought to such convergency as to form the image of an object, proceed, after that, diverging in the manner they did when they issued from the object before they were transmitted through the glass , and therefore they may be again collected by another spherical glass, so as to form a 2d representation of the same object ; which may again be repeated by a 3d glass, &c. So that the first image may be considered as an object to the 2d glass, and the 2d image will be an object to the 3d, and so on. Though these images may be very different in respect to their magnitudes, yet they will be all similar; being true representations of the same object: this will hold good, though the 2d glass should be put so near the first, as to receive the rays before the image is formed : for as the rays are tending to meet at a certain distance, the 2d will receive them in that degree of convergency, and, by an additional refrac- tion, bring them to a nearer focus ; but the image will still be similar to that which would have been made by the first glass, if the 2d had not been there. On this principle all refracting telescopes are made ; some of which are a com- bination of 4, 3, or 6 glasses. The first glass forms an image of the object ; the 2d repeats the image, which it receives from the first ; and so on, till the last glass brings a true representation of the object to the eye. The same may be said of reflecting telescopes : for a spherical mirror acts in the same manner, in that respect, as a spherical glass. Now let this be applied to the subject in hand. Suppose the focal distance of the divided object-glass to be about 40 feet ; and suppose the segments to be opened wide enough to bring the opposite edges of an object in contact : then VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 467 let another object-glass, uncut, be fixed within the tube, of a proper degree of convexity, to shorten the focus of the other as much as may be required ; sup pose to 12 feet: by what has been just now observed, this glass will represent the two images in the same form which would have been exhibited by the divided glass, if this other glass had not been there. For though the images are not yet formed, when the 2d glass receives the rays ; yet, as those rays are converg- ing towards it, the 2d glass must represent those images in the same position, and form, as the tendency of the rays requires. For while the segments are fixed in their position to each other, their images will also be fixed in their po- sition ; and let them be repeated ever so many times, by refraction through sphe- rical glasses, or by reflexion from spherical mirrors, they can suffer no alteration in their position to each other. By this means the telescope may be shortened at pleasure, though the scale for the measure of the angles will remain the same. The only inconvenience which the shortness of the telescope introduces, is a want of sufficient distinctness ; which will so far hinder the exactness of the observa- tion, as the contact of the edges cannot be so accurately determined, as they might be with longer telescopes. This difficulty is entirely removed by fixing the divided glass at the end of a reflecting telescope : for the reflections and refractions, which the rays must un- dergo in passing through the telescope, will no way alter the position of the images which the rays, that have passed through the segments, are tending to : for, as has been already observed, a number of reflections and refractions may repeat the images, and alter their magnitudes ; but can make no alteration in their proportions. Therefore this way of fixing the divided glass to a reflecting telescope, which was the 3d method proposed, is by far the best ; as such telescopes of moderate and manageable lengths, when well made, are capable of magnifying conside- rably, and showing objects to great advantage. This micrometer's being appli- cable to the reflecting telescope with so much certainty, is no inconsiderable ad- vantage : for any one will easily understand, that to measure the diameter of a planet exactly, it is necessary that the planet be magnified, and shown distinctly, which could not be obtained in the common way without very great lengths ; such as rendered it very difficult, not to say impracticable, to take exact mea- sures. Besides, the common micrometer is limited in this respect on another account ; viz. because the diameter of the planet cannoi be measured without having the whole planet within the field of the telescope, which confines the magnifying power within very narrow bounds ; whereas, by this method, nothing more is required, than to see the contact of the edges, which allows the magni- fying power to be increased at pleasure. In the common micrometer, the object is to be taken between 1 wires, so 3 o2 468 PHILOSOPHICAL TRANSACTIONS. [annO 1754. that the contact of its edges with those wires cannot be observed at one view ; and the least motion of the telescope, while the observer is turning his eye from one wire to the other, must oblige him to repeat the observation ; whereas, by this method the contact of the edges of the images is not at all affected by the motion of the telescope. Whence the comparison of this micrometer with the common sort, in this respect, stands thus : the one requires great steadiness in the telescope, but yet it is applicable to none but such as are very difficult to keep steady ; the other does not require such steadiness, though it is applicable to short telescopes, which are easily managed. These advantages not only add to the certainty of the observation, but assist vastly in the expedition ; for an observer may make 20 observations in this way, where he could scarcely, with much fatigue, be sure of one with the common micrometer. Expedition in making observations must be allowed a very great advantage, in this climate, where the uncertainty of the weather renders astronomical observations so pre- carious, that no opportunities, even the most transient, should be let slip. An instance of this was given in to the r. s., in an account of the eclipse of the sun last October. As the motion of the telescope gives the observer no great incon- venience in this method ; neither does the motion of the object at all disturb his observation, such a motion as that of the heavens is. This gives him leave to take the diameter of a planet in any direction ; or the distance between two stars or planets, let their situation be how it will ; in which respect the common mi- crometer is absolutely defective ; as it can give no angles, but su'^h as are per- pendicular to the line of their motion ; though the diameters of the planets, in other directions, is very much wanted ; it being highly probable, from the laws of motion, and what we see in Jupiter, that such planets as revolve round their axes, have their polar diameters shorter than their equatorial ones. The distances of Jupiter's satellites from each other, or from Jupiter's body, cannot be measured, with any certainty, in the common way, as their position is always very far from being at right angles with the line of their motion : nei- ther can the moon's diameter, which must be taken from horn to horn, scarcely ever be obtained that way, because it very rarely happens, that the diameter to be measured lies at right angles to the line of her motion. The same may be said of the distance between two stars, But this micrometer gives angles, in every direction, with equal ease and certainty ; the observation being also finished in an instant, without any trouble or fatigue to the observer. For as there are no wires made use of this way in the field of the telescope ; so the observer has no concern about any illumination. The largeness of the scale deserves also to be taken notice of, as it may, in this micrometer, be increased almost at plea- sure, according as the smallness of the object requires. Another inconvenience attending the common micrometer is, the variation of the scale, according to the VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 469 distance of the object. As the telescope must be lengthened, or drawn out far- ther, for short distances ; the scale, which depends on that length, is thereby in- creased ; which renders the measure of the angle very uncertain : whereas, in this micrometer, the scale is the same at all distances : so that the angle may be measured with the utmost certainty, without any regard to the distance of the objects. On the whole, it may be concluded, that this micrometer is a complete instru- ment in its kind ; having many advantages above the common sort, without any of their disadvantages : and there is no doubt but, when brought into practice, it will tend much to the advancement of astronomy. LXXF. Of an Earthquake felt at York, ^pril IQ, 1754. By Mr. David Erskine Baker, p. 564. This small shock felt by Mr. B. at York, lasted about 3 seconds. It gave an undulating motion to the buildings, made the windows, &c. rattle, and was pre- ceded by a rumbling noise, like a carriage over a pavement. Its direction seemed to be from s.w. to n.e., and it was felt at several other places, at many miles distance. LXXVI. An Investigation of some Theorems which suggest some Remarkable Properties of the Circle, and are of Use in Resolving Fractions, whose Denomi- nators are certain Multinomials, into more Simple ones. By Mr. John Lan- den.* p. 566. That the principal theorems, below investigated, will be of considerable use in the doctrine of fluxions, by rendering, in many cases, the business of computing * Mr. Landen, who was born at Peakirk near Peterborough, in Northamptonshire, in I719» was in a great measure a self-taught mathematician, a branch of learning in which he rose to the first rank of eminence. He became a respectable contributor to the mathematical part of the Ladies* Diary so early as the year 1744 ; to which work he continued his contributions, either in his own name, or under various fictitious ones, till within a very few years of his death. His first paper in the Phil. Trans, above printed for the year 1754, is no mean specimen of his taste and skill in that line. Besides this, and several other valuable papers printed at different times in these Transactions, he published some curious and separate works himself. As, 1. Mathematical Lucubrations in 1755; containing a variety of tracts relating to the rectification of curve lines, the summation of series, the finding of fluents, 8lC. 2 A Discourse on the Residual Analysis, 1758; being a new branch of the algebraic art, of very extensive use, both in pure mathematics and natural philosophy. 3. The 1st book of the same Residual Analysis, in 1704 ; explaining the principles, and applying them in a number of curious speculations. 4. Animadversions on Dr. Stewart's Computation of the Sun's Distance from the Earth, 1771. 5. Mathematical Memoirs, 17S0, vol. i. ; on a variety of subjects; with an ap- pendix containing a very extensive collection of forms for finding fluents. 6". Several Observations on converging Series, in 1781, 1782, 1783. 7. And lastly the 2d vol, of the Mathematical Memoirs, in the latter end of 1789 ; containing, besides a solution of the general nroblem concerning rotatory 470 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. fluents more easy, will, on perusal, be obvious, Mr. L. says, to every one ac- quainted with that branch of science. Art. 1 . — Supposine '^=- = — » where x and y denote the fluxions of the variable quantities x and y respectively, and n an invariable quantity ; it is proposed to find, in terms of^ and z, the equation of which z is a root, and z^ — 2.rz + 1 = O, a divisor. Taking the fluents of the given fluxionary equation, we have, supposing x = 1 when y is = 1, hyp. log. of {x + y^x^ — l)" = hyp. log. of y + \/y^ — i, or (ar + Vx^ — \y =y + '^y'^ — 1 : whence, by substituting for x its value— -^^ (found by the equation z' — 2xz +1=0), we have z" = y -\- ^ y~Iir\ •_ there- fore z" — yis = ^y"^ — 1 ; and, squaring both sides, z^" — lyz' + ^^ = ^' _ i. Consequently z^' — lyz' + 1 is = O; which, supposing n a positive integer, is the equation sought. Now it is obvious, n being such an integer, that this equation will have as many trinomial divisors, of the form z' — Ixz -|- 1, as there are values of x corres- ponding to a given value oiy: which values of .r, when y is not greater than 1, nor less than — 1 (the only case I propose to consider), will not be readily ob- tained from the equation {x -\- »/ x^ — Xf ■=y -\- V y- — 1 found above: but, if we multiply the given fluxionary equation by , we get — -— — = — ^ — ; of which the equation of the fluents is n X circ. arc rad. 1, cosine x = circ. arc rad. 1 . cosine y ; where a; is := 1 when y is = 1 , agreeable to the supposition made above, when we took the fluents of the given fluxionary equation by loga- rithms. Therefore if a be put for the least arc whose cosine is y, and c for the whole circumference, radius being 1 ; y being the cosine of a, a -j- c, a -j- 2c, A + 3c. &c. X will be the cosine of ^, ^t_E, L+_2£ &c to Lti^JZ^JiS, Consequently, expressing the last-mentioned cosines, or the several values of motion, an investigation of the naotion of the equinoxes, in which Mr. L. has, first of any one, pointed out the cause of Sir Isaac Newton's mistalie in his solution of this celeb; ated problem. Mr. L. as he had chiefly completed this work during some intervals from the stone, with which disorder he was severely afflicted in the latter part of his life, so he just lived to see it printed, and received a copy of it the day before his death, which happened Jan. 15, 17i)0, at Milton, near Peterborough, being 7 1 years of age. About the year 1762, Mr. L. became agent and land-steward to Earl Fitzwilliam; an employment which he resigned only 2 years before his death. And in 1766 he was elected f. u. s. Though Mr. L. was doubtless one of the greatest mathematicians that this or any country has produced ; his merit in this respect was not more conspicuous than his moral virtues. As his compositions were profound, and elegantly clear and simple ; so his manners and deportment were manly, dignified, genteel, and be- nevolent. The strict integrity of his conduct, his great humanity, and readiness to serve every one to the utmost of his power, procured him respect and esteem from all his acquaintance. TOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 471 X, by f), q, r, s, &c. z"" — 2i/z" + I will be = {z" — 2pz + \) X (z' — 2^2 -\- 1) X {z' — 2rz + l)> &c. («), when n is a positive integer, (as we shall al- ways suppose it to be), let z be what it will. Hence may be easily deduced a demonstration of that remarkable property of the circle first discovered by Mr. Cotes : but as that property has already been demonstrated by several mathematicians, Mr. L. omits taking any further notice of it, and proceeds in the investigation of soiiie other useful theorems which had never been published. ^rt. 2. — If j/ be = 1 ; then, a being = 0; p, q, r, &c. will be the cosines of ?-, -, --, — , &c. (n) respectively : therefore /> will be = 1 ; and, if n be an even number, one of the cosines q, r, s, &c. will be := — 1 , one of the arcs £ £L — &c. being then = ^. y/r/. 3. — If?/ be = — 1 ; then, a being = r 5 P) ?' ^^ *> &^- will be the co- sines of—, — , -T-, &c. (n) respectively: therefore, if n be an odd number, one c of those arcs will be ^ , whose cosine is — 1 . yJrt. 4. — If, in the equations z'" — 2yz" +1=0, and z^ — Ixz -\- 1=0, we substitute « — 1 for z, they become {v — xY"" — 1y X {v — l)" -\- 1 =0, and {v — \y — 1x X (f — l) + 1 = v" — (2 + 2jr) X v + 1 + 1x = Q. Consequently On 1 ~ i;'" — inv"-"-' + + -In X — — - v" — Inv +1 . . . . -f- 2yn X — -— v^ + 2ynv -f- 1y (y'' — 2 + ip X V + 1 + 1 p) X {v" — 1 -\- 1q X V + 1-\- 1q) X {v" — 2 +2r X y -|- 2 + 2 + 2r) X &c. (n) ; where, of the two signs prefixed to the terms where ^ is a factor, the upper or lower takes place, according as n is an even or an odd number. Whence, by the nature of equations, it follows, that (2 + 2p) (2 + 2q) X (2 + 2r), &c. is = 2 + 2y. But this equation vanishing when y is = 1 and n an even number, or when 3/ is = — 1 and n an odd number, it will be proper to consider those two cases more particularly. Jrt. 5. — First, let us suppose 7/ = ], and n an even number: then p being = 1, and one of the other cosines q, r, s, &c. = — 1 (Jrt. 2) ; we shall have , D^" — 2wt;'"-' + + w' i;^ = (v' + O) X (v'' — 4i; + 4) X {v'' — 2r+2q) X {v + 2+ 2q) X {v'—2 + 2r X V + 2 + 2r), &c. Therefore dividing by v'', v"^-" — 2m/'^M- +n' ={v^ — 4v +4) X {v^— 2 + 2q X v + 2 + 2g X (u'^ — 2 + 2r X V -\- 2 -\- 2r), &c. that factor in which the value of the co- sine q, or r, &c. is — 1, being expunged. 472 PHILOSOPHICAL TRANSACTIONS. {[anNO 1754. Consequently n' is = 4 x (2 + Iq) X (2 + 2/) X (2 + 2*), &c. when the factor, whose value is nothing, is expunged. ^rt. 6. — Let us now suppose y = — 1, and n an odd number: then one of the cosines p, q, r, &c. being = — 1 {Art. 3), ^2n _ m^_^ + w'li' will be = {v" + 0) X [v" — 1 + 1p X v + 2p) X (t^' — 2 + 1q X t^ + 2 + 29) &c. Therefore, dividing by v^, '■ — 2to''"-' + -\- n^ will be = (t;* — 2 + 2j& y. v + 1 -\- ip) X {v^— 2 + 2q X V + 2 + 2q), &c. and consequently n^ = (2 + 2p) X (2 + 2q) X (2 + 2r), &c. when the factor, whose value is nothing, is expunged. Art. 7. — Substituting in the equations z'-" — 2j/z" 4-1=0, and 2^ — 2xz + 1=0, (— — ) instead of 2, we have ^O — u' and (^-^—Y—lx X — 1- i = (" + ")'- ^■^ X (" + ") + ("-'") + (" - ■")' ^ a — «' a — « (a — »)* 1 — J' = ■ r i-^ — = O. Consequently, (a — «)* ^ -^ (a + 0,)'" - 23/ X (a + o))" X (« - ")" + (a-«r will be = (2 + 2p) X (2 + 2^) X (2 + 2;), &c. X (^.^ + —^ a') X («' + ~f a^) X (o,^ + —^ a^), &c. But, by Art. 4, (2 + 2p) X (2 + 2q) X (2 + 2r), &c. is = 2 + 2j/, the upper or lower of the two signs prefixed to y taking place, according as n is an even or an odd number. Therefore (a -f «)'" — 2y X (a + «)" X (a — u)" + {a — w)" is = (2 + 2i/) X ("' + ^-f-«^) X (<-♦ +~^- «^)X {.' + — ->^), &c. Now/) being the cosine of any number of degrees, radius being 1, a^ will be the square of the tangent of half so many degrees, radius being a : therefore, denoting that tangent by b ; and the tangents of half the arcs described with the radius a, whose cosines, when the radius is 1, are q, r, s, &c. being denoted by c, d, e, &c. respectively ; we have (a + u)" — 2j/ X (a + w)" + (a — u)" + (n - 6,)'^" = (2 + 2y) X ()" = Ian X ^ u^ -\- b" X V u^ -\- c% &c. la taking place instead of ■v/j^^ -f. sq. of the tang, of QO"; and, when n is an even number, {a + w)" + (a — w)" = 2 X ^^I^b"- X V^w^ -f ^, &c. Hence we infer this construction. Art. 13, Having described about the centre c (lig, 3 and 4) with the radius a, the circle va'K'a"x", &c. draw the diameter pca, and the tangent b"¥h*; divide the semicircumference pa'a into as many equal parts va', a k, x'a", &c. as there are units in In; draw the secants ca'b', ca"b", &c. and, through any point (o) in ca, draw k"oh* parallel to b"sb*; likewise draw b'k', b"k", &c. parallel to pa; and call CO, u. Then, if the radius be 1, /> will be the cosine of twice the angle pca', q the cosine of twice Pca", &c. therefore vb' = ok' will be = b, vb" = ok" = c, &c. and ck' = -^^J+l-^ ck''= ^ u,'' +7=, &c. Consequently op" + pa" being =_(«_+ ")" + (« — ")"j and ?2 X Pa X ck' X ck", &c. = 2an X V''^'^ -\- b"^ X /w' + c*, &c. when n is an odd number; op"+ oa" will then be = ra X pa X c/4' x ck", &c. where the diameter pa takes place instead of the infinite quantity cA^""*"*- But if n be an even number, op" + oa" will be = 2 X c^' X ck'\ &c. Art. 14, It is obvious that, of the factors ck', ck", &c. the first and last, the second and last but one, &c. are respectively equal to each other: therefore the squares of the factors below pa, and the squares of their values, being omitted, OP" + oa" is = n X pa X ck'^ X ck"\ &c. and (a + «)" + (a — «)" = 2an X (a« _|- /,«) X (u" + c^), &c. when n is an odd number; or op" -|- oa" is = 2 X ck' X ck'\ &c. and (a + «)'" + (a - i.)" = 2 X (co' + Z-') X (<.' + c'), &c. when n is an even number. Art. 15. Writing, in the equation (a + wf — 1y X {a ->{- w)" X (a — «)" + (o — !o)'" = (2 + 2y) X («* + i') X («* + c»), &c. (found by art. 7) a — m for u, the same becomes (2a — «)*" — 2j^m" X (2a — u)" + w'" =. (2 T 2y) x VOL. TLVIII.] PHILOSOPHrCAL TRANSACTIONS. 475 (u — 2au + a* + b') X («' — lau + a* + c»), &c. = (2 + 2y) X (u* — 2ciu + (3") X ("' — 2au -f y") X (?i — 2rtw + i*), &c. if instead of Vq' + 6% t/a* + t'j ^f^- (tlie secants of the arcs of which b, c, d, &c. are tangents) we put p, y, S, &c. And, by a like substitution in the equations in art. 1 1 and 14 it appears, that (2a — w)" — u" is = 2an X {a — u) X (u' — 2au + y'') X (u' — 2au + ^), &c. or 2 (a — w) X («' — 2au + y') X (?«' — 2au -^ i''), &c. according as n is an even or an odd number: and that (2a — u)" + m" is = 2a« X (m' — 2au + (3*) X («' — 2aM + y"), &c. or 2 X (n' — 2au + (3*) X (m' — 2aM + y ), &c. ac- cording as n is an odd or an even number. LXXFII. An Extraordinary Disease of the Shin, and its Cure. Extracted from the Italian of Carlo Crusio. By Rob. Watson, M.D., F.R.S. p. 579. A young woman of 17, the daughter of a citizen of Naples, was brought to the royal hospital June 22, 1732, and was placed in one of the wards assigned to the care of Dr. Crusio; who was informed by her, that her complaint was an excessive tension and hardness of the skin over all her body, by which she found herself so bound and straitened, that she could hardly move her limbs. He found her skin hard to the touch, like wood, or a dry hide; however, he ob- served some difference in the degrees of the hardness; for in some places it was greater; as in the neck, forehead, and particularly in the eye-lids; so that she could neither raise nor entirely shut them. It was also very great in the lips, tongue, and on each side of her body ; but the muscles under the skin seemed not to be affected, because the joints could be bent; and if in any place there was any difficulty in moving the limbs, this arose not from any defect in the muscles, but from the hardness and tension of the skin and cellular membrane, which did not yield to their contraction and relaxation. Her skin had lost its natural warmth, but was sensible, when it was pressed by the nails, or a pin; the patient then saying, that she felt a pain, as if the skin were tearing. Her pulse was deep, and obscure; but equal, and regular. Her respiration was free, and uninterrupted; her digestion good, and she found no inconvenience after eat- ing, except a greater constriction round the belly. The alvine excretions were easy and proper; but the urinary sometimes exceeded the quantity of what she drank, and appeared loaded with salts ; both which circumstances perhaps pro- ceeded from the sensible and insensible perspiration being entirely wanting. For ' she never sweated, though ever so much exercised. Her sleep was natural; she had never had the menstrual evacuation. Her disorder began first in her neck, when she could not move it as usual ; then she found the skin of her face and forehead grow hard ; and so successively, she found all the external parts of her 3p2 476 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. body grow hard, and tense. She never had had any other disease, except a little fever sonic years before. Respecting the indication of cure of this extraordinary disease, as the skin was observed to have lost its natural softness and flexibility ; and to have become , hard, contracted, and imperspirable ; it was concluded that the immediate cause of such a morbid change was a preternatural contraction of the nervous or fibrous parts of the skin, by which its excretory ducts and exhaling vessels were constringed, and did not supply a due quantity of the oily and aqueous fluids necessary to soften and lubricate the parts. Hence it was thought fit to put the patient into a bath of warm milk and water, and to direct her to stay in it a con- siderable time, that the warmth and moisture might relax and soften the hard- ness of her skin : but she could not bear to continue in the bath, on account of the great oppression which it occasioned, and because the troublesome constric- tion of her skin was much increased by it. She was therefore put to bed, and well covered with clothes, in hopes to promote a sweat , but all was in vain ; for her skin remained as hard and dry as before. However, this treatment was repeated for 6 days ; but, on going into the bath for the 7 th time, she was seized with convulsions in the muscles of her legs and arms. This was very unex pected, and made it necessary to discontinue this method of cure. But as it was imagined that it was the weight and pressure of the water which gave her so much uneasiness, a method was thought of to avoid this inconvenience, and at the same time to procure for the patient the benefit, that might arise from the relaxation and softening of the skin and pores by the absorption of an external humidity, which was judged to be necessary to the cure. Now the vapour of warm water has a great power of insinuating itself into the pores, and between the fibres of bodies ; and, by that means, of relaxing and softening the hardest substances, as is observed in dry leather ; which, suspended in the steam of boiling water, becomes much more soft and pliable, than if it had been im- mersed for a longer time in the hot water itself. A vapour bath was therefore ordered, and contrived in such a manner, that the steam of the boiling water might entirely surround the body of the patient, or be directed to any particular part, as occasion should require. She bore the vapour without any inconveni- ence, and was constantly kept in bed in the intervals between the several appli- cations of it. The 6th time of using this kind of bath, she began to perspire a little, and from day to day the perspiration became more general, and at last universal : then the skin began to be less rough, but not less hard ; and the urine was more thin and diluted than before. Her diet was prescribed to be of the most soft and relaxing nature, and principally consisted of whey. As she was judged to be of too full a habit, and as she had not the regular menstrual discharge, she was ordered to lose 12 oz of blood fi-om the foot; and it was VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 477 thought that this evacuation might contribute to produce a general relaxation, and by consequence make the circulation of the blood, and other fluids, more free tlirough their respective canals. It was surprising to see what difficulty the surgeon found in opening the vein, on account of the hardness of the skin ; in- somuch that, in the operation, the lancet yielded, and bent. However, at last it pierced the skin and the vein, but not without much pain. The blood issued forth with impetuosity, and the wound was some time before it healed; but at length it formed an elevated and hard scar. By continuing the emollient diet and vapour bath, in about 40 days the skin of her legs, where the hardness appeared the latest, began to soften. But as often as she exposed herself to the fresh and cool air, the skin, which had begun to be soft and flexible, was observed to become hard again, and imperspirable. It was therefore thought proper, towards the end of September, to place her in a warm room, where the air was kept of an equal degree of heat. This had the desired effect: for by staying in her room, and from time to time repeating the vapour bath, and by drinking, at her meals, a decoction of the woods, the perspiration was constant and moderate; and the softness of the skin, which began in the legs, extended itself upwards, and was in some degree perceptible in the arms. Five months had elapsed since the beginning of this treatment, when it was believed that, without some more efficacious medicine, capable, by its motion, weight, figure, and divisibility, of circulating with the blood, and of penetrating into the most remote and subtil recesses of the vessels, it would be impossible to open the obstructions, which were formed in the vascular structure of the skin, and which, by hindering the fluids from circulating through their respective canals, had deprived them of that humidity, which nature has made necessary for their flexibility and softness. It was therefore thought proper to make her take small doses of pure quicksilver; and that the mercury might the more easily be determined to the skin, the patient was ordered to be constantly kept in a warm air, to have the surface of her body rubbed with a flannel, and to continue the use of the vapour bath. But, by way of preparation for this mercurial course, she was gently purged, and blooded a second time, that the plenitude being diminished, the mercury might better circulate through the finest vessels. Here it is to be observed, that the surgeon, in this 2d blood-letting, did not meet with that resistance, in piercing the skin, which he had experienced in the first. The patient, thus prepared, began in December, 1752, to take daily 6, and afterwards 12 grs. of pure quicksilver, in a drachm of cassia, drinking after it half a pint of a decoction of sarsaparilla. In this course she continued 4 months with chearfulness, and without any inconvenience; and within 2 months from the beginning of it there appeared a somewhat viscid sweat, and the skin grew more flexible, and yielding. About the end of March, 1753, she had an eflSo- 478 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. rescence over all her skin, which by degrees became pustular, and was very troublesome by its heat and itching. The use of mercury was then discontinued, and she took no medicine but half a pint of an infusion of sarsaparilia in the morning, and an emulsion of melon and poppy-seeds in the evening. Then the heat and itching abated, and the pustules suppurated. Signor Crusio says, that he had the pleasure to see many small globules or particles of mercury separated in the ripe pustules. This is something so unusual and surprising, that we shall scarcely be inclined to give our assent till we are forced to it by further experience and observation ; especially as we know that the most careful and sensible men are often mistaken ; but that it is very rare that any thing happens out of the ordinary course of nature.* About the middle of May following, her skin was quite clear of pustules, and was become perfectly soft and flexible, being capable of being moved, raised, extended, and of performing all its natural functions. This softness and flexibi- lity of the skin was general, except in the forehead and lips; which however afterwards recovered their natural state. But there still remained an unusual degree of tension in some of the muscles, which lie immediately under the skin, particularly in those of the hand and radius; on which account, a milk diet was prescribed, to supply the blood with a proper matter for filling the cells of the adipose membrane; which membrane, by having sustained a long pressure between the diseased skin and muscles, was become deprived of its proper muci- laginous and oily juices, designed by nature to keep the parts soft and flexible, and to facilitate the motion of the muscles. LXXVIII. Experiments on the Use of the Agaric of Oak in Stopping Hemor- rhages. I. The Event of Experiments made by Agaric on the imputation of the Legs of 2 Women in Guy's Hospital. By Mr. Samuel Sharp, Surgeon of that Hospital, and F.R.S. p. 588. The styptic powers of the agaric were tried on 2 women, whose legs were amputated below the knee. One of them was 62 years of age, and had been very much impaired by a long illness, and continual pain. During the operation she bled with great impetuosity; and it was with difficulty, that the hgemorrhage was stopped, notwithstanding Mr. S. pressed the agaric, with all his force, against the extremities of the tibialis antica, and tibialis postica, the 2 largest arteries. The tendency to bleed, after the operation was such, that Mr. S. found it necessary to apply the tourniquet, and keep a tight stricture on the femoral artery. She complained grievously of the pain arising from the stricture; on which it was a little loosened, and soon after a haemorrhage ensued from one of * This remark seems to have been introduced into the text by the editor of the original Transactions. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 479 the 2 large arteries, which was immediately taken up, and tied with a needle and ligature. In order to discover this vessel, the agaric was removed; and though the tourniquet was quite slack, the other large artery did not bleed one drop. This happened about \'^ hour after the operation. After the vessel was tied, the same agaric was again laid on the same part, without screwing the tourniquet, and the patient became much easier; but, in about 84- hours, the other large vessel burst open; and though assistance was on the spot, and it was immediately tied up, she was so exhausted by the sudden loss of blood, that she died in about twenty minutes. It is conjectured, that, by the 3 haemorrhages, viz. the first during the operation, and the 2 after the operation, she lost between 20 and 30 oz. of blood. Mr. S. examined the limb after death, but found no singular ap- pearance in the vessels, or the adjacent parts. The other woman was 24 years of age. She lost very little blood in the operation, and had continued extremely well ever after. The agaric seemed in this instance, to have answered the most sanguine expectations. The following are the particulars of this case, as related by Mr. Warner: II. The History of a Case relating to the Effects of the Agaric of Oak in Stopping HiEmorrkages. By Joseph JVarner, Surgeon to Gui/s Hospital, and F.R.S. p. 590. Saturday, December 9, 1752, Catharine Spong, aged 24, had her leg ampu- tated, about 4 inches below the knee, at 12 o'clock to-day, on account of an incurable ulcer, with which she had been afflicted for 13 years. She lost very little blood by the operation. Immediately after the amputation, a piece of agaric, of a proper size was applied to the mouths of the principal arteries. Two other pieces of agaric were applied to the mouths of 2 smaller arteries, which ap- peared at some distance from the principal ones. On the pieces of agaric, dossils of lint were applied, and over all a pledgit of tow spread with the common digestive ; all which were kept on by the common bandages made use of in the like cases, and ajjplied with the same degree of tightness as usual. For an hour and a quarter after the operation, the ligature and tourniquet were kept on moderately tight, at a convenient distance above the knee, at the end of which time it was slackened, so as to have no degree of pressure on the femoral artery, as the dressings and rollers appeared very little tinged with blood. The patient was much easier than Mr. W. had ever observed, after the use of the needle and ligatures. Her pulse appeared very little disturbed till about 4 o'clock this afternoon, when the symptomatic fever began to come on, attended now and then with convulsive twitches of the stump, and thigh; for which reasons, the ligature was somewhat tightened. At 7 o'clock this evening the ligature and tourniquet were quite loosened ; soon after which, the convulsive 480 PHILOSOPHICAL TRANSACTIONS. [ANNO 1754. twitches became less frequent, and less severe. These convulsive twitches she had been long used to, and, by her own account, they were more severe before the operation, than they have been since. She had but little rest to night. Sunday morning, at 4- after 10 o'clock, she appeared as well as could be expected, her pulse was calm, and she had no particular complaints. At 12 o'clock at night she fell asleep, and so continued till after 7 o'clock the. next morning. Monday morning she appeared well, her pulse was calm, and she had no par- ticular pain. Monday night she slept but little, but was very easy the whole night. Tuesday morning she appeared well, her pulse quiet. That morning at 1 1 o'clock, she was dressed in the usual manner: the wound had a very good as- pect; she had suffered no particular pain in the parts where the agaric was applied, and was, in all respects, as well as could be expected. At 7 o'clock in the evening she was perfectly easy ; the convulsive twitches, which she at first com- plained of, were then quite removed. Wednesday morning, she continued well, and perfectly easy ; had no return of her convulsive twitches, nor was there any appearance of blood through the rollers, or dressings. Thursday, Dec. 14, she continued very well. Her wound was dressed that morning, at -l after 1 1 o'clock, when there appeared a very proper discharge of matter, not in the least tinged with blood. The whole of the agaric, with the rest of the dressings came off, without giving pain. She had the day before 2 or 3 convulsive twitches of the stump, and thigh, but they were slight. Her pulse was good. II. A short History of -the Effects of the Agaric of the Oak in Stopping Bleedings after some of the most capital Operations in Surgery; with an Account of the Manner of its acting on the Vessels. By Joseph fVarner, F.R.S. and Surgeon to Guys Hospital, p. 593. The success which attended the application of the agaric in the instance of the young woman, the particulars of whose case have been stated in the preceding paper, induced Mr. Warner to try its effects in 4 other cases, the histories of which are as follows: Case 1 . — ^Jonathan Lee, aged 5 1 , had his leg cut off, below the knee, on the 7th of May, 1754. He was extremely reduced, in consequence of the disease; and the whole mass of blood was become so much impoverished, and altered from its natural state, as to appear like serum, both in texture and colour. During the operation, the screw-tourniquet was applied to the thigh with a de- gree of tightness sufficient to prevent the course of the blood. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 481 Immediately after the amputation, bits of agaric were applied to the mouths of the vessels, and on them soft layers of lint ; all of which were covered with a pledgit of tow spread with digestive, and were properly secured on by the com- mon bandage. About 3 or 4 minutes after he was rolled up, and put to bed, Mr, W. discovered the blood to discharge freely through the dressings; on which, he tightened the tourniquet, in expectation of stopping the bleeding, but it ap- peared evidently to increase it. Seeing this uncommon effect, Mr. W. quite slackened the tourniquet; on which, the bleeding immediately ceased. This he was led to from a supposition, that the veins had probably suffered so great a compression from the instrument, as to be incapable of returning that blood, which was carried to the neighbouring parts by the collateral arteries arising from the principal trunk, above the ligature. But whether this was the true reason, or not, he would not take upon him to determine : however the fact was, that the bleeding immediately ceased, and did not return again. The patient was dressed on the 4th day after the operation, and the whole of the agaric was removed. Since that time he had been treated in the common method, without any further use of the agaric. The patient had very little fever, or pain, after the operation. He had a fair prospect of doing well. Case 1. — Elizabeth Hillier, a very lusty woman, 38 years of age, had her breast cut ofFon the 7th of May, 1754. The wound was large, and bled freely from several considerable arteries. Mr. W. made use of no other method to stop the bleeding, than the application of pieces of agaric to the mouths of the vessels, which were properly secured on by a flannel roller, after being first co- vered with lint, and a pledgit of tow spread with digestive. The symptomatic fever was very slight • she had been quite free from those painful spasms which constantly arise from ^e use of the ligature : there had not been the smallest loss of blood since the operation. Her wound was dressed on the 4th day, when the whole of the agaric came away: it was afterwards treated in the common method. She was in a very fair way of recovery. Case 3. — George Whitmore, aged 12 years, had his leg cut off, below the knee, on the 13th of May, 1754. The agaric and dressings were applied as in the preceding cases, which has answered perfectly well in all respects. The tour.p niquet was quite removed in 10 minutes after the operation ; he had very little fever, restlessness, or pain. His wound was dressed on the 5th day, and the whole of the agaric was removed. He was as well as could be expected. Case 4. — Richard Barnat, aged 54, had his leg cut off, below the knee, on the 21st of May, 1754. Mr. W. made use of no other methods to stop the bleeding than the agaric, which was applied as in the preceding cases. Imme- diately after the operation, the patient was put to bed, antl the tourniquet let VOL. X. 3 Q 48'2 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. quite loose. He has not sustained the smallest loss of blood since the opera- tion. The pain and fever had been very inconsiderable, and he seemed to be in a very fair way of doing well. LXXIX. Of a new Pyrometer, with a Table of Experiments made with it. By Mr. J. Smeaton, F. R. S. p. 5Q8. This instrument is capable of receiving a bar 2 feet 4 inches long, and might be made capable of receiving bars of a much greater length, of some kinds of materials, but not of others, on account of the flexibility brought on them by a degree of heat not greater than boiling water. The measures taken by this instrument are determined by the contact of a piece of metal with the point of a micrometer-screw. The observation is the best judged of by the hearing, rather than that of the sight or feeling. By this method Mr. S. found it very practicable, to repeat the same measurement several times, without differing from itself above -j-o-Fo-r P^rt of an inch. This principle of determining measures by contact is not wholly new, but has been employed on several occasions, as he was informed by the late Mr. Graham ; but the pre- sent manner of applying it he believes is so: and the degree of sensibility arising from it exceeds any thing he had met with. As the method will easily appear by the draught (see pi. g, fig. 10 and 11) he avoids a further description of it in this place.* As no substance has hitherto been discovered in nature, that is perfectly free from expansion by heat, I chose to construct this instrument in such a manner, that the bar, which makes the basis of the instrument, shall in each experiment suffer the same degree of heat, as the bar to be measured: of consequence, the measures taken by the micrometer are the differences of their expansion. The expansion then of the basis between two given degrees of heat being once found, the absolute expansion of any other body, by adding or subtracting the difference to or from the expansion of the basis, according as the body to be measured ex- pands more or less than the basis, will also be determined. When the instrument is used, it is immerged, together with the bar to be measured, in a cistern of water; which water, by means of lamps applied under- neath, is made to receive any intended degree of heat, not greater than that of boiling, and so communicates the same degree of heat to the instrument, the bar, and to a mercurial thermometer immerged in it, for the purpose of ascer- • I have lately seen an instrument at Mr. Short's, made by the late Mr. Graham, for measuring the minute alterations, in length, of metal bars; which were determined by advancing the point of a micrometer- screw, till it sensibly stopped against the end of the bar to be measured. This screw being small, and very lightly hung, was capable of agreement within the 3 or 4000th part of an inch. — Orig. VOL. XLVIII."! PHILOSOPHICAL TRANSACTIONS. 483 taining that degree. That this may be truly tlie case, the water should be tre- quently stirred, that there may be no difterence of heat in the different parts of the water: this being tlone, the height of the quicksilver appearing stationary, the contact with the screw of the micrometer also remaining the same, for a space of time, it is to be supposed, that the heat of the 3 bodies will be the same as the heat of the water, however different they may be in specific gravit}', &c. The whole difficulty is now reduced to this problem, viz. To find the absolute expansion of the basis between any two given degrees of heat, not greater than that of boiling water. For this pui-pose, let there be prepared a bar of straight-grained white deal, or cedar, which, it is well known, are much less expansible by heat than any metal hitherto discovered: let the bar be adapted to the instrument in like manner as the other bars intended to be measured; but that the softness of the wood may not hinder the justness of its bearings, let its ends be guarded with a bit of brass let into the wood at the points of contact: to prevent, as much as may be, the moisture or steam of the water from affecting the wood; let it first be well varnished, and then, being wrapped round with coarse fiax from end to end, this will in a great measure imbibe the vapour, before it arrives at the wood. Let the cistern also be so contrived, that the instrument being supported at a proper height in it, the bar to be measured may on occasion be above the cover, while the basis remains in the water: thus will the cover also be a defence against the moisture. Let the water in the cistern be now brought to its lower degree of heat, suppose at or near the freezing point, the basis having continued long enough in the water to receive the same degree of heat, and the wooden bar having been previously kept in an adjacent room, not subject to sudden altera- tions of temperature by fire, or other causes; let the bar be applied to the in- strument, and the degrees of the micrometer and the thermometer read off, and set down : let the wooden bar be then restored to its former place, till the water is heated to the greater degree intended, suppose at or near that of boiling water; the lid being now shut down, and the chinks stopped with coarse fiax, to pre- vent the issuing of the steam as much as possible, let the wooden bar be again brought forth, applied to the instrument, and the degrees of the micrometer and thermometer read off, as before: the difference of degrees of the micrometer, corresponding to the difference of degrees of the thermometer, will express the expansion of the basis between those degrees of heat ; that is, on the supposition that the wooden bar was of the same length, at the time of taking the second measure, as at the first; indeed a measure can hardly be taken without any loss of time, as the whole of the instrument, when the hot measure is to be taken, is considerably hotter than the wooden bar; and, in case of boiling water, the 3 a 2 484 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. steam being very repellent and active, the bar is liable to be sensibly affected in its length, before the measure can be taken, both by heat and moisture, which both tend to expand the bar; but as the quantity is small, and capable of being nearly ascertained, a wooden bar, thus applied, will answer the same end as if it was unalterable by heat or moisture. To know therefore the quantity of this alteration, let the time elapsed between the first approach of the bar to the instru- ment, and the taking of the measure, be observed by a second-watch, or other- wise; after another equal interval of time, let a second measure be taken ; and after a third interval, a third; and a fourth; the three differences of these four measures will be found nearly to tally with three terms of a geometrical progres- sion, from which the preceding term may be known, and will be the correction, which, if applied to the measure first taken, reduces it to what it would have been if the wooden bar had not expanded during the taking of it. From a few observations of this kind, carefully repeated, the expansion of the basis may be settled; and this once done, the making experiments on other bars will become very easy and compendious. The basis of this instrument, as well as other parts of it, is brass. He chose this substance, rather than any other whose expansion was greater or less; because he found, from some gross experiments previously made, that the expansion of brass was nearly a medium between those bodies which differ most in their ex- pansion: a considerable convenience arises from this circumstance; because as the measures, taken in common experiments, are their difference from brass, the dependence on the thermometer will be less, as these differences are less. The bar of brass which compose the basis, is an inch broad by half an inch thick, and stands edgewise upwards ; one end is continued of the same piece at right angles, to the height of 3-i- inches, and makes a firm support for the end of the bar to be experimented ; and the other end acts on the middle of a lever of the second kind, whose fulcrum is in the basis; therefore the motion of the ex- tremity of the lever is double the difference between the expansion of the bar, and the basis. This upper part of the lever rises above the lid of the cistern, so that it and the micrometer-screw are at all times clear of the water. The top of the lever is furnished with an appendage which he calls the feeler: it is the extre- mity of this piece which comes in contact with the micrometer-screw. It hence appears, that having the length of the lever from its fulcrum to the point of suspension of the feeler, the distance between the fulcrum and the point of con- tact with the bar, the inches and parts that correspond to a certain number of threads of the micrometer, and the number of divisions in the circumference of the index-plate; the fraction of an inch expressed by one division of the plate may be deduced; those measures are as follows. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 485 From the fulcrum of the lever to the feeler 5.875 inches. From the fulcrum to the place of contact 2.895 Length of 70 threads of the screw 2.455 Divisions in the circumference of the index-plate. ... 100 Hence the value of one division will be the ^ ,\% ^ part of an inch ; but if the screw be altereil ^ of one of these divisions, when the contact between the screw and feeler is well adjusted, the difference of contact (if he may so call it) will be very perceivable to the slightest observer; and consequently -g.-3-i-, ^ part of an inch is perceivable in this instrument. There is one thing still remains to be noticed, and that is, the verification of the micrometer-screw, which is the only part of this instrument that requires exactness in the execution ; and how difficult these are to make, perfectly good, is well known to every person of experience in these matters; that is, that the threads of the screw may not only be equidistant, in different places, but that the threads shall be equally inclined to the axis in every part of the circumference. The result of the experiments made with this instrument, agrees very well with the proportions of expansion of several metals given by Mr. Ellicott; which were deduced from his pyrometer published in the Philosophical Transactions: and, considering the very different construction of the two instruments, they abundantly tend to confirm each other. Referencti to the Figures. Fig. 10, pi. 9. represents the instruinent independent of the cistern in which it is used, abcd, is the main bar or basis of the instrument, ef, is the bar to be measured, lying in 2 notches; one fixed to the upright standard ab, the other to the principal lever hi. The end e of the bar bf, bears against the point of g, a screw of use in examining the micrometer-screw. The other end of tlie bar F bears against a small spherically protuberant bit of hard metal fixed at the same height as o, in the principal lever hi. k, is an arbor fixed in the basis, which receives at each end the points of the screws hl, on which the lever hl turns, and serve as a fulcrum to it. o, is a slender spring, to keep the lever in a bearing state against the bar; and p, is a check, to prevent the lever from falling forward when the bar is taken out. n, is the feeler, something in the shape of a t, suspended, and moveable up and down on the points of the screws im, which, as well as lh, are so adjusted, as to leave the motion free, but without shake, qr, is the handle of the feeler, moveable on a loose joint at R; so that, laying hold of it at q, the feeler is moved up and down without being affected by the irregular pressure of the hand. The extremity s of the feeler is also furnished with a bit of protuberant hard melal, to render its contact with the point of the micrometer-screw more perfect. T, is the micrometer-screw ; v is the divided index-plate, and w a knob for the handle. The micro- meter-screw passes through two solid screwed holes at d and y. The piece yz is made a little springy, and endeavours to pull the screw backwards from the hole at d ; of consequence keeps the micrometer-screw constantly bearing against its threads the same way, and so renders its motion perfectly steady and gentle, x, is the index, having divisions on it, answering to the turns of the screw. This piece points out tlie divisions of the plate, as the face of the plate points out the divi- sors on the index. When the instrument is used, lay hold of the knob at q with one hand, and, moving the feeler up and down, with the other move forward the screw i, till its point comes in con- tact with the feeler; then will the plate and index v and x show the turns, and parts. 486 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. Fig. U, represents the instrument immerged in its cistern of water, ready for use. ab, is the cistern; c, tlie cover; which, when the instrument fig. 10 is raised on blocks, goes on between the bar EF and the basis bc. d, a handle to take otF the cover, when hot; k, the mercurial thermo- meter; F, the cock to let out the water, gh, a hollow piece of tin, which supports seven spirit lamps, which are raised higher or lower by the screws l and k, in order to give the water in the cis- tern a proper degree of heat. A Table of the expansion of metals; showing how much a foot in length of each grows longer by an increase of heat corresponding to 180 degrees of Fahren- heit's thermometer, or to the difference between freezing and boiling water, expressed in such parts of which the unit is equal to the lOOOOth part of an inch. 1 White glass barometer tube 100 1 1 Brass wire 232 2 Martial regulus of antimony 130 12 Speculum metal 232 3 Blistered steel 138 13 Spelter solder, viz. brass 2 parts, zink 1 247 4 Hard steel 147 14 Fine pewter 274 5 Iron 151 15 Grain tin 298 6 Bismuth l6'7 l6' Soft solder, viz. lead 2, tin 1 301 7 Copper hammered 204 17 Zink 8 parts, with tin 1, alittle hammered 323 8 Copper 8 parts, mixed with tin 1 218 18 Lead 344 9 Cast brass 225 19 Zink or spelter 353 10 Brass l6 parts, with tin 1 229 20 Zink hammered half an inch per foot . . 373 It is now several years, says Mr. S. since I first observed the very considerable expansion of the semi-metallic substance called zink, spelter, ortootanag; and proposed it tis more fit for the purpose of making compound pendulums, and metalline thermometers, than brass ; as its expansion seemed considerably greater, and its consistence, when gently hammered, not much inferior. With the same view I have made trial of several other metallic compositions, besides what is above set down; but they all proved much inferior to zink in expansion, and most of them in consistence. It seems, that metals observe a quite different proportion of expansion in a fluid, from what they do in a solid state; for regulus of antimony seemed to shrink in fixing, after being melted, considerably more than zink. LXXX. On the Sex of Holly. By Mr. John Martyn, F. R. S. Professor of Botany in the Universiti/ of Cambridge, p. 6 13. The holly, agrifolium, or aquifolium, is described by all authors as bearing hermaphrodite flowers ; but Mr. M. thinks that this tree is male and female in different plants. He had in his garden at Streatham in Surry, 6 pretty large plants, with differently variegated leaves, in full flower, 3 males, and 3 lemales, growing in pairs, and a male growing by itself, in another part of the garden. The female is that which has been described by authors, and he did not know that any one had described, or even taken the least notice of the nsale. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 487 The male flower, as well as the female, is monopetalous, cut deeply into 4 segments, with a very small empalement, divided also into 4 parts. It has 4 conspicuous chives, which sustain yellow summits, in which is great plenty of farina; but it has nothing like either stile, or ovary. The female flower has, besides its essential pait, the ovary, 4 snort filaments, which have hitherto been taken for chives, or male organs of generation ; but as he could not perceive that they bear any summit, or yield any farina or fecundating dust, he rather believes that they are tubes, which assist in conveying the impregnating particles to the seeds; which opinion seems in some measure confirmed by the germ being placed in the lower part of the seed, according to Caesalpinus, who ranges this tree among those quarum semina cor in inferiore parte habent. Ray has placed it among the arbores flore, fructui contiguo; but Mr. M. thinks it ought to be removed to the arbores flore a fructu remote. It must also be removed from the tetrandria tetragynia of Linneus to the dioecia tetrandria. But if the 4 filaments in the female flower should be found, on a more accurate observation by better eyes, to be real chives, and to contain a fecundating dust, it will belong to the polygamia. But whether the tree, which he verily believes to be purely female, is really so, or hermaphrodite, he is certain that the other is purely male; and even in this case his observation is new. Mr. IV. JVatsons Opinion on Mr. Martyns Paper on the Sex of the Holly, p. 6 15. I first examined, in company with Mr. Miller, the holly trees in the botanical garden at Chelsea. We there found, as Mr. Martyn had, that the flowers were of different sexes; but not as those in the Dr.'s garden, male and female on dif- ferent plants, but female and hermaphrodite on different plants. I afterwards, both at Hampstead, and at the duke of Argyll's at Whitton, observed several trees bearing male flowers, others female flowers. Hence it appears, that not only Mr. Martyn's obser\'ation of the holly being male and female in different trees is well founded, but also that it is male, female, and hermaphrodite, on diflferent trees; and I should not wonder, if on a still further examination, as in the mulberry, that the male and female flowers of the holly should be found, not only on different, but on the same tree: or even, as in the empetrum, or berry- bearing heath, that some holly-trees should be found bearing only male flowers, others bearing only female flowers, others only hermaphrodite flowers, others both male and female, others both male and hermaphrodite, others female and hermaphrodite, others still bearing flowers male, female, and hermaphrodite oa the same tree. The holly therefore, as Dr. Martyn has justly observed, should be removed, in the system of Linni'us, from the tetrandria tetragynia; but not to the dioecia tetrandria, but ratlier to the class polygamia, and to the order trioicia. 488 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. LXXXI. A Continuation of ihe Account of the JVecither in Madeira. By Dr. Thomas Heberden. p. 617. This paper contains first a medium of the greatest, least, and mean height of the barometer and thermometer, at Funchal in Madeira, for each month of the years 1751, 1752, 1753, which have but very small differences and changes. By collecting the respective sums of the daily heights of the instruments throughout the year, and extracting the mean altitude, it is found that the mean altitude of the barometer for each day, is 29.9 15 inches, and of the thermo- meter, 68°.918. The greatest barometrical variation, during 4 years and 4 months, has been -^ of an inch only, viz. from 29.3 to 30.2. The greatest thermometrical variation, during the said time, has been 20", viz. from 60° to 80°; but it may be observed, that it never rose so high but once; occasioned by a very strong leste or levant wind ; the extreme height, without such an accident, being never more than 78°. The quantity of rain which fell in the 7 years, from 1747 to 1753, inclusive, amounts to 214.346 inches. Therefore the mean quantity for each year is 30.62 +. LXXXII. On Father Kircher's Opinion concerning the Burning of the Fleet of Marcellus by Archimedes. By James Parsons, M. D., F. R. S. p. 62 1. Dr. P. says, that though the machines invented by Archimedes when Mar- cellus besieged the city of Syracuse, as described by Livy, Plutarch, and Poly- bius, were wonders, surpassing the comprehensions of the generality of mankind, yet what was most discredited, was Archimedes's setting fire to the ships, by a burning speculum. Indeed so distinguished a genius, if he could not destroy them in that manner, must know, that he might have thrown combustible matter, sufficient to burn the galleys, from his projectile machines; for we cannot ima- gine that he was ignorant of every kind of these, and not even of the wildfire of the Greeks. But, however, to account for his burning the fleet, by a spe- culum, was the difficult point. When philosophers began to increase their catoptrical experiments, which they did very early, they found the focus, of every speculum that was concave, so short, that they were easily inclined to conclude that Archimedes could not set fire to the fleet by a speculum ; and hence the fact became entirely discredited, till Kircher, and his pupil Schottus, whose characters and works the learned world is well acquainted with, resolved to consider not only the story of Archi- medes, but also that of Proclus, who is said to have destroyed a fleet at Con- " stantinople in the same manner. Kircher however, notwithstanding the incre- dulity of the learned of his time, was not deterred from giving attention to the VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 489 matter himself; which led him to make innumerable experiments, to see whether it were possible to be done or not, before he would give any opinion about it ; and at length, when he had commended the parabolical speculum, which he and others were inclined to think the most likely to succeed in such an enterprize ; he was inclined to think that Archimedes made use of such a speculum. But soon afterwards he became dissatisfied with this notion, and beginning to make new attempts, he fell upon one which lessened his former good opinion of the parabolical speculum, and made him more sensible of the inconveniencies attending it, or those of any other form, that had any great degree of concavity ; and in short engaged him entirely in favour of his new thought, which was put in execution in the following manner : He erected a frame, on which he placed 5 plane specula, of equal given di- mensions, with such inclinations as made them all throw their reflected rays on the same place, at more than 100 feet distance. When he had set the first spe- culum, he went and laid his hand on the place where he caused the rays to fall, and found it warm ; when he added those of the 2d, the heat was doubled ; the 3d increased the heat in the same proportion ; and the 4th being added, the heat was scarcely to be borne ; but the 5th made it intolerable. Whence he con- cludes, that, by multiplying those specula, the heat might be so increased, as to set fire to combustible matter at greater distances, according to the number applied. Schottus gives the same account of Kircher's experiment. He accompanied him in all his trials, as well as in his journey to Syracuse, after he had brought his plane mirrors to answer his purpose ; and, on viewing the place, they both concluded, that the galleys of Marcellus could not be farther than 30 paces from Archimedes. And yet Schottus declared, that if a concave speculum could be constructed, as large as the rotunda, it could not have a sufficient focus to effect what both Archimedes and Proclus are said to have done. Thus we see Kircher had scientifically established the problem, for the con- struction of a burning machine, consisting of any number of plane specula ; which was afterwards further confirmed by BufFon, as appears in 2 letters ; printed in these Trans.* If so, we cannot suppose he could have seen what either Kircher or Schottus had written about it. LXXXIII. On several Bones of an Elephant found at Leysdoivn in the Island of Sheppey. By Mr. Jacob, Surgeon al Feversliain. p. 626. Three or 4 years before Mr. J. had sent the acetabulum of an elephant, which was discovered sticking in the clay, which was partly washed away from the clifti i • See page 344 of the 9th vol. of these Abridgments, VOL. X. 3 R 490 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. at Leysdown, in the isle of Sheppey, a mile eastward of the cliffs of Minster. This, with other parts, as one of the spinal vertebrae, a thigh-bone 4 feet long and numberless other fragments, too rotten to be then taken up entire, he saw ; all which lay below high-water mark : and as the place, and some adjacent land, soon after, became his property by a purchase he made, he went, attended by workmen, in search of more, and found an elephant's tusk; and, as it lay entire to appearance, took its dimensions ; which were, in length, 8 feet ; and in cir- cumference, in the middle, 12 inches: but it fell all to pieces, when they en- deavoured to raise it. He found also part of a scapula, its sinus almost entire, and 3 inches diameter. He found also some pieces of grinders. The pyrites however abounds so much in the clay where this animal was embedded, that he despaired of finding any whole bones : but he thinks these fragments are suf- ficient to show, that the elephant was as large as that mentioned by Tentzelius, in these Transactions. The apex of the tusk, which Mr. J. preserved, together with the acetabulum, were both found within 20 feet of the other bones mentioned, and were, as Mr. J. apprehended, in better condition then than at the above date, from their being taken up immediately on being discovered, and not left to be exposed to the injury of the weather, and violence of the tides ; which soon affects bodies so ex- posed, after having lain under ground for ages. LXXXIF. On the Animal Life of those Corallines, that look like Minute Trees, and grow upon Oysters and Fucuses all round the Sea-coast of this Kingdom. By Mr. John Ellis, p. 627. The doubts still remaining on the minds of many learned men, of the animal nature of corallines, on account of their beautiful ramifications, and regular plant- like appearances, determined Mr. E. to persuade Mr. Ehret to accompany him to the sea-side, that he might there be an eye-witness of what he had advanced, and to make exact drawings of the several different objects, as they appeared to him through the microscope. Accordingly, June 3, 1734, they set out, and arrived at Lewes in Sussex that evening, and the next morning at Brighthelmstone. The weather being very calm, and few fucuses or corallines being thrown ashore on the beach, they hired a fisherman, the next day, to take up some, oysters from an old oyster-ground, that had been long disused, lying about 3 or 4 leagues off to sea, and where, by his description, the shells were covered with great varieties of these minute tree- like corallines ; with directions that, as soon as he took them out of the sea, he should immetliately put them into a bucket of sea-water ; but unfortunately he put the oysters into a fisherman's basket ; by which means many varieties were dead, though they received them 2 hours after they were taken out of the sea. VOL. XtVIII.] PHILOSOPHICAL TRANSACTIONS. 49I and had tliem put immediately into sea- water: however, by the oysters lying on each other, some of the corallines were kept so moist, as to be perfectly alive and brisk. In order to distinguish them more easily, they plucked them off the oysters, and placed them in white earthen plates, and poured as much sea-water over them as would just cover them. After letting them rest for a little while, to recover themselves, they could easily discover, with a magnifying glass of an inch focus, which were alive, and which not: accordingly, Mr. E. cut off" small pieces of several of the liveliest, and placed them in watch-glasses filled with sea- water ; these, after resting a little while, he placed, one after another, on the stage of the microscope. The unusual sight so amazed his friend (who had his doubts), that he could scarcely believe his own eyes ; for he had hitherto ima- gined, with many others, that these corallines were vegetables, and only the re- ceptacles of animals, as many other plants are, and not the proper cases, skins, or coverings, of their bodies. The first coralline* that offered itself to their view, was N° 1, pi. 12, where it is represented, in its natural appearance, climbing on the podded fucus a, with irregular thread-like ramifications, as at b; one of which is exhibited magnified at A, in which is observed a broad dark line in the middle of the transparent stem and branches. This is part of the tender body of the animal, and seems as a support for its several heads and stomachs, with the many hands or claws be- longing to each : for at the top of each of the branches we may observe a polype with 20 tentacula, or claws, which do the office of hands, its mouth being in the centre of them, and its stomach underneath, inclosed in a fine transparent cup. The fine outlines represent the horny skin, or outer coat, that serves this com- pound animal as a defence, in the same manner as the shells of testaceous or crustaceous sea-fish. The skin or covering of the arms, that support the cups, is formed in small rings, which gives the animals the more freedom to move about dextrously in seizing their prey. ""^ At letter b is the microscopical representation of a still smaller coralline -j- than the former; the size of it a little reduced is expressed at fig. 2. This creeps up, and twines round other corallines by small vermicular tubes, and sends out its curious slender anus itregularly : these arms, in the microscope, look like rows of the smallest beads of a necklace : to the top of each of these is fixed a cup, for the reception of the polypes, the brim of which is curiously indented. These thej saw alive, and extending themselves about in various directions. Fig. N° 3, represents part of another coralline,;}: just as it appeared expanded in a plate of sea-water. It is called, in Ray's Synopsis, ed. 3, corallina ramosa cirris ob- * Sertularia geniculata, Linn. f Sertularia volubilis. Linn. Gmel. I Sertularia antennina. Linn. 3 r2 492 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. sita; and by Doody, in Ray's Synopsis, ed. 2, fruticulus elegans geniculatus cirris obsitus. Letter c expresses a branch of this coraUine magnified ; where you may observe, on each capillary side-branch, rows of small polypes, each with 8 tentacula, or claws, rising out of little sockets. The upper division or tube of these little branches, as at b, appears full of joints, one to each polype ; but they could easily perceive that all the polypes were connected together, and communicate with the principal stem, or body, which is inclosed in the middle tube. The under small tube of the capillary side-branch at c, which runs pa- rallel with the upper one b, and adheres to it, appeared clear, hollow, and jointed. This coralline arises from a tuft of small irregularly-matted tubes, like a sponge growing to an oyster-shell, as at g; the smaller branches e are inserted in circles round the larger branch f, at equal distances, like the plant called horsetail, or equisetum. As they were observing these corallines, they perceived, on one of them, a different-shaped polype, which pushed itself out of a small funnel-shaped pipe : this was inserted in a cell, whose brim or border was surrounded by little spines. These cells composed that spongy rough matter, which incrusts almost all marine substances, but chiefly fucuses. Fig. 4 represents these cells on a fucus ; letter d expresses the cells and polypes, with 1 1 tentacula to each, as they appear magnified ; where the animals are seen raising and expanding them- selves. When they are disturbed, they draw themselves within their sheath or pipe, which closes on them, and sink together into their cells. The curious denticulated coralline* at N" 5, has very much the appearance of a plant, at first view, even when it is magnified, as at e. This gave a further corroborating proof, that these extraordinary species of beings are animals : for they observed that the smaller polypes, that extend themselves out at the open- ing of every opposite denticle, or little projecting tube, are united at the bottom, or lower part, to the fleshy substance of the main body, that passes through the middle of each branch, or stem, and are so many dififerent bodies united in one ; acting like so many sets of hands, placed in form of a circle, collecting food, each for a mouth in the centre, to convey nourishment to so many stomachs, which are fixed in the swelling part, or bottom, of each denticle. This great supply of nourishment from all sides, gives that great increase, and variety of ramifications, to this wonderful class of many-bodied animals. Besides these small polypes, which compose the branches, these corallines send forth, from several parts, many vesicles, of different shapes, at certain seasons of the year, according to their different species. These vesicles are protruded from the outer skin or horny covering of these branched polypes, and from the * Serlularia rosacea. Linn. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 493 inner or fleshy part arises a large polype ; one of which occupies each of these vesicles. Thus a coralline full of vesicles looks like a plant full of blossoms, which, after they have arrived at their perfect state, fall ofF, with their capsules or vesicles, and become new-detached animals, to provide for themselves ; in the same man- ner as the falling seeds produce other plants. On examining this coralline, they found that the animals in the vesicles were dead ; but immediately afterwards they had an opportunity of discovering the vesicular polypes alive, in another coralline ; * which are described at fig. 6, and at letter p as they appeared magnified. This species Mr. E. called the sea-oak coralline, from its being most frequently found creeping on, and adhering to the largest species of the quercus marinus, or sea-oak fucus. The vesicles of the denticulated coralline, letter e, are described as they ap- peared full of spines at the top, and closed up, as at letter g. The vesicles of the same species are more frequently found as described at i, where the spines are not unfolded : from this appearance, he called it the pomegranate-flowering coralline, because they nearly resemble the opening blossom of the balaustine, or double flower of the pomegranate. The branches of this coralline are often observed to end in vermicular tubuli, as at H, which are much of the same form with those it begins with ; so that these animals can, and do, change their shapes, for the several ends and pur- poses of their being ; and this in a most surprising manner. He had further an opportunity of examining some of those kind of corallines, which he called celleferous, from their having rows of cells disposed in plant- like ramifications. The small black spots in each cell^ which he had conjectured before to be the embryo of a future testaceous animal, (Vid. Phil. Trans, vol. 48, tab. 6, p. 115) he found now to be the contracted bodies of dead polypes; for they here saw some of these polypes -|- alive, and extending themselves out of their cells, as at k, fig. 7 ; and on reviewing them, when they were dead, found they made the appearance of blackish spots in each cell, as at l, fig. 7. So that they had reason to suppose that this species of polypes that form these corallines, do change into testaceous bodies. LXXXF. Extract of a Letter from Camillo Paderni, fCeeper of the Museum Herculaneum, to Tho. Holies, Esq. Dated at Naples, ^pril 27, 1754. p. 634. The place where they are digging at present, is under II Bosco di Sant' Agos- tino, but a little distant from the royal palace at Portici. Its depth is 125 Nea- * Sertularia putnila. Linn. t Sertularia scruposa. Linn. 494 PHILOSOPHICAL TRANSACTIONS. [anNO 1754. politan palms,* one of which is more than the mercantile canna of Rome. All the buildings discovered in this site are noble : many of the pavements are of mosaic, variously and finely made ; others are of different-coloured marbles, dis- posed vi^ith a beautiful symmetry ; and most of them are already taken up. In one of these buildings there has been found an entire library, composed of volumes of the Egyptian Papyrus, of which 250 have been taken out ; and the place is not yet cleared or emptied, it having been deemed necessary to erect props first, to keep the earth, which lies above it, from falling in upon it. These volumes of Papyrus consist of Latin and Greek manuscripts ; but from their brittleness, occasioned by the fire and time, it is not possible to unroll them, being now decayed and rotten. There have been found some of those small tables, which they covered with wax and the palimpseston, and then wrote on them with the stylus : but all these are become a kind of cinder ; and have also suffered by the damps ; from both which circumstances they are now so tender, that they break with the touch. In the same place there have been found 3 small busts ; one of Epicurus, an- other of Zeno, and the third of Humachus ; with the names of each inscribed on the basis, in Greek letters. A little distant from the preceding site has been discovered another noble building, with a square court belonging to it ; the inside of which alone has been hitherto examined. This square is formed with fluted columns made of brick stuccoed. In the angles were 4 terms of marble, with busts on them, in bronze, of the finest manner, having the name of the Greek workman on one of them. In the centre, between the terms, was a small foun- tain, formed by a vase shaped like a cockle-shel), and supported by a small fluted column. There have been also found 3 other busts, large, and in bronze, likewise of the most excellent workmanship. Within these few days the following things have been taken out of the same site ; viz. a female statue, 6 palms high, per- haps a goddess, though without any attribute, and but of middling workmanship; 2 most beautiful candlesticks, S-J- palms high, exquisitely wrought in chased work ; other candlesticks, much damaged by the fire and time ; many fragments in bronze, which, not having any particular merit, it is needless to describe, except two small figures of fawns, that are finely executed. In the same place was discovered a large fountain, lined throughout with lead : round it were 1 1 heads of lionesses, out of which the water flowed. Pipes of lead are very often met with ; and scarcely a day passes but something is brought. LXXXVl. Experimental Examination of a White Metallic Substance said to be found in the Gold Mines of the Spanish West-Indies, and there known by the * A Neapolitan palm is said to be 11-| inches English. — Orig. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS, 495 A[ypellations qfPlatina. Platina di Pinto, Juan Blanca. By fVilliam Lewis * M.B., F.R.S. p. 638. PAPER I. Expcr. ] . — The substance brought into England under the name of platina appears a mixture of dissimilar particles. The most conspicuous, and by far the largest part of the mixture, are white shining grains, of seemingly smooth sur- faces, irregular figures, generally planes with the edges rounded oiF. On exa- mining these with a microscope, the surface appeared in some parts irregular, tlie prominencies smooth, bright, and shining ; the cavities dark-coloured and roughish. A few of them were attracted, though weakly, by a magnetic bar. These grains are the true platina. The heterogeneous matters intermixed among them, in the several parcels, were, 1. A blackish dust, separable by a fine sieve. This was further divided, by a magnetic bar, into 1 different substances : the part attracted was of a fine sparkling black colour, much resembling the black sand from Virginia : the part not attracted was of a dark brownish hue, with several bright molecuL-e, which appeared to be fragments of the grains of platina. 2. Among the larger grains, separated by a coarse sieve, were sundry irregular dark-coloured particles, some blackish, others with a cast of brownish red, in appearance resembling frag- ments of emery or loadstone. Several were attracted weakly by the magnet. 3. There j\'ere a few rough yellow particles, resembling gold, which on further examination they were found to be, though probably not entirely free from pla- tina. 4. A few globules of quicksilver, containing gold, with some particles of platina intermixed and pretty strongly adhering. 3. Some fine transparent par- ticles, probably spar. 6. A very few irregular particles, of a jet black colour. These broke easily, and looked like the finer kinds of pit-coal. Laid on a red- hot iron, they emitted a yellowish smoke, and smelt like burning coal. -|- • Tills memoir, with its continuations in the 50th vol. of the Phil. Trans, is one of the most va- luable chemical papers which had hitherto been presented to the u. s. Some years afterwards, these papers were reprinted by Dr. Lewis, accompanied with an account of all that was then known re- specting platina, in his Commercium Philosophico-Technicum, a work containing much useful infor- mation, and, at the same time, suggesting various improvements in the arts connected with chemistry. Beside these. Dr. L. published a Course of Practical Chemistry j a translation, with notes, ot" Neumann's Chemistry ; a New Dispensatory ; and an Experimental History of the Materia Medica. The last 2 works are of the highest merit in their kind, exhibiting (to use the words of an able critic on this subject) correct descriptions of drugs, with useful experiments in their treatment by different menstruums, while the author is very chaste in ascribing virtues, and in repeating from former writers. And from his own experience, as well as that of the most skilful London practitioners, he gives a sounder judgment of the real virtues of medicinal substances than had been given before. When Dr. Lewis died, or what was his age, at the time of his decease, or any other particulars concerning his life, we have not been able to learn. \ From the experiments of later chemists, it appears that the ores of platina contain several distinct 496 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. Remarks. — 1. It appears from the foregoing observations, that this mineral has not come to us in its native form ; being probably taken out of the mines in large masses, which have been broken, and treated with mercury, to extract the gold, of which possibly it at first contained a considerable quantity. The quan- tity left by the workmen is extremely small ; some pounds of the mixture having yielded only a few grains. A moderate fire renders more of these golden particles discoverable, than can be seen at first ; the mercury evaporating, by which se- veral of them were concealed. 2. Some part of the brownish powder is probably adventitious, as well as the mercury ; being worn off from the stampers and mills employed for comminuting the mineral, and triturating it with the mer- curv. 3. The roughness and dark colour of the cavities of the grains of platina, seem to proceed from a substance similar to the black dust adhering in them. It is probably owing also to this heterogeneous magnetic matter, that some of them are attracted by the loadstone. Exper. 1. — Some of the purer grains of platina, by gentle strokes of a flat hammer, on a smooth anvil, bore to be considerably flattened, without breaking or cracking about the edges : some quickly cracked, and discovered internally a close granulated texture. All are reducible, by rude strokes in an iron mortar, though with difficulty, into powder. They seemed to be rather more brittle when ignited, than when cold. Exper. 3. — The specific gravity of platina, with its heterogeneous admixtures, as brought to us, was found to be to that of water, as 16.995 to 1.000. The quantity weighed for this purpose was no less than 2000 Troy grains. The larger grains of platina, separated as much as possible from the other matters by the sieve, and cleansed by heating, boiling in aqua fortis, mixing them with sal ammoniac, and forcing off" the salt by fire, and afterwards washing them; weighed in air 642, in water 606.75 : whence their gravity turns out 18.213. The microscope still discovered a considerable portion of blackish mat- ter in their cavities. These trials were several times repeated on different parcels of platina : the result was nearly the same in all. Remark. — The gravity of this mineral, great as it appears to be from the fore- going experiments, would probably turn out still greater on a further purifica- tion of the platina, since it is manifestly mixed with some of the lighter hetero- geneous matters. Exper. A. — A quantity of platina, containing its usual admixture of magnetic dust, was kept for some time of a moderate red heat in an iron ladle. The bright particles became somewhat duller coloured ; the magnetic ones were no metallic substances. See Wollaston in Phil. Trans, for 1804 and 1805, as before quoted at p. 103 of this vol. of these Abridgments. VOL. XLVm.] PHILOSOPHICAL TRANSACTIONS. -197 longer attracted. In other respects there was no sensible alteration. 2. An oz. of platina was urged with a strong sea coal fire, in a blast-furnace, for above an hour : the heat was so vehement, that the black-lead crucible vitrified, and the slip of Windsor brick, which covered it, melted and ran down. The grains of platina were found superficially cohering into a lump, of the figure of the bottom oi the crucible, of a brighter colour than at first. On a slight blow, they readily fell asunder again, and seemed not to have altered their shape. 3. In several repe- titions of the experiment, the platina began to cohere in a moderate white heat : the grains were at this time very easily separable, and seemed to cohere the more strongly in proportion as the heat was raised. In the most intense fires, which the common vessels could not long support, the platina did not melt, or soften, or alter its figure, or lose sensibly of its weight. The colour was constantly brightened by a strong heat, and generally rendered dusky by a small one : on quenching it, when violently heated, in cold water, the grains, which composed the internal part of the lump, acquired a violet or purple colour. Exper. 3. — 1 . As the power of fire on metallic, as well as earthy substances, is remarkably promoted by the immediate contact of fuel, and the impulse of air on the subject ; platina was exposed to its action in those circumstances. A cru- cible, having a bed of charcoal in it, was laid on its side, in a good blast-lur- nace, with its mouth towards the nose of the bellows ; and 4 ounces of platina spread on the charcoal. The fire was vehemently urged for above an hour, during which an intense white flame passed through the crucible, and issued at an aperture made for that purpose. The crucible was vitrified : the grains of platina only superficially cohered, and became brighter, as in the preceding ex- periment, without seeming to have softened or altered their shape. 2. The ex- periment was several times repeated, and varied : once, common salt was thrown on the fuel before the crucible, and its fumes strongly impelled on the platina : some platina was likewise placed before the nose of the bellows in violently-ex- cited sea-coal fires, so strong as almost instantly to melt off a piece of the end of a forged iron rod, without effect ; except that once there were a very few globu- lar drops, about the size of very small shot : these broke easily on the anvil, and looked, both internally and externally, like platina. Remark. — It is probable, that the fusion here was owing to sotne accidental admixture, possibly iron : for the unmelted grains, exposed afterwards to a fire rather more intense, suffered no sensible alteration. Exper. Q. — Platina was likewise exposed to the fire in conjunction with se- veral substances, which are found to promote the fusion of other bodies, or to occasion considerable alterations in them. 1. Platina mingled with powdered charcoal, with compositions of charcoal, soot, common salt, and wood ashes, substances employed for changing iron into steel ; suffered no change in weight VOL. X. 3 S 4QQ PHILOSOPHICAL TEANSACTIONS. [aNNO 1754. or appearance, whether urged with an intense fire, or cemented for many hours in a weaker one. '2. Platina was injected into melted borax, and urged with an intense fire for several hours, without undergoing any alteration. Nor had black, flux, common salt, pure fixed alkaline salts, or caustic alkalies, any sen- sible effect. 3. Vitreous matters were no more powerful than the saline. Pla- tina was kept in strong fires, for several hours, with common green glass, with glass of antimony, and with glass of lead, without seeming to be in the least acted on by either. 4. Platina was likewise stratified with plaster of Paris, a powerful flux for the most difficultly-fusible metallic body hitherto known, forged iron ; as also with quicklime, and with calcined flint ; with as little effect as in the former trials. Exper. 7. — Nitre, which reduces all the known metallic bodies, except gold and silver, into a calx, was mixed with an equal weight of platina, the mixture injected into a strongly ignited crucible, and the fire kept up for a considerable time ; no deflagration happened ; and the platina, freed from the salt by re- peated ablutions with water, proved of the same weight and appearance as at first.* Exper. 8. — 1. An ounce of platina was spread on twice its weight of sulphur, with which some powdered charcoal had been previously mixed to prevent its becoming fluid in the fire so as to suffer the platina to subside. The crucible, having another with a hole in the bottom inverted into its mouth, was kept in a cementing furnace for several hours ; when the sulphur was found to have en- tirely exhaled, leaving the platina separable from the charcoal by washing, with- out alteration or diminution. '2. We likewise varied the experiment, injecting repeatedly pieces of sulphur on platina strongly heated ; and constantly found that pure sulphur had no more effect on this mineral, than on gold itself. 3. As fixed alkaline salts enable sulphur to dissolve gold ; platina was exposed to the fire with a mixture of sulphur and alkali, called hepar sulphuris. After a consi- derable heat had been continued for some time, and the matter occasionally stirred, very little of the platina was found remaining in its proper form ; the greatest part being taken up by the sulphureo-saline mixture, so as to dissolve along with it in water. General Remarks. — It appears, from the foregoing experiments and observa- tions, 1 . That probably this mineral is originally found in large, hard masses, composed of true platina, a substance similar to the black Virginia sand, and an- other ferruginous matter of the emery kind, some spar, and particles of gold. 1. That these masses are, not without great labour, reduced into small grains, which are afterwards ground with mercury, in order to extract the gold. 3. * SeeTenuant on the Action of Nitre on Gold and Platina in the Phil. Trans, for 1797. VOL. XlVIir.]| PHILOSOPHICAL TRANSACTIONS. 499 That the pure platina is a white metallic substance, in some small degree mal- leable ; that it is nearly* as ponderous as gold, equally fixed and permanent in the fire, equally indestructible by nitre, unaffected by sulphur, dissoluble by hepar sulphuris. That it is not to be brought into fusion by the greatest degree of fire procurable in the ordinary furnaces, whether exposed to its action in close vessels, or in contact with the fiiel ; by itself, or with the addition of inflam- mable, saline, vitreous or earthy fluxes. -)- PAPER II. The more obvious properties of this extraordinary mineral, and its habitus to fire, singly, and in conjunction with the various substances called by the che- mists fluxes, made the object of the first paper. In this, it is proposed to exa- mine the effect of acid spirits, simple and compound, applied after various manners ; in order to determine not only its relation or habitus to them, but likewise its less obvious agreement or disagreement with the metallic bodies, whose history is more known. The platina employed in the following experiments was previously freed from its fine dust by a sieve ; from the mercury, by ignition ; and from the golden and some of the other heterogeneous particles, by the eye assisted with glasses. Exper. 1 . — Platina with the FitrioUc Acid. 1 . Several parcels of platina were digested for some hours, in a gentle heat, with spirit of vitriol, both con- centrated, and diluted with different proportions of water. No solution hap- pened, nor any sensible alteration, either in the liquors or the platina. 2. Three ounces of well-dephlegmated spirit of vitriol were boiled with one ounce of pla- tina, in a tall, narrow-necked glass, for some hours. The liquor remained nearly of the same quantity as at first ; and no change could be perceived either in it, or in the platina. 3. The glass being cut off a little above the liquid, the, heat was gradually increased, till the liquor, which now began to evaporate, had, in 5 or 6 hours, totally exhaled, and the platina become dry, and red-hot. When cooled, washed with water, and exsiccated, it was found exactly of the sam^ weight as at first, and its grains not divided, or apparently altered. Remark. — Platina appears therefore entirely to resist the vitriolic acid ; which, by one or other of the above processes, dissolves or corrodes every other known metallic body, except gold. Exper. 1. — Platina with the Marine Acid. 1. Weak and strong spirits of salt being digested, separately, with -^ their weight of platina, in a gentle • More ponderous than gold when duly purified, its specific grarity being then 23.000; wherea* that of gold is only 19.3. + White arsenic excepted ; for on exposure to a sufficient degree of heat, with such an addition, it may be brought into fusion. 3s2 300 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. heat, for several hours, the liquors remained uncoloured, the platina unaltered, and undiminished. The heat was afterwards increased, and the liquors kept strongly boiling till they had totally exhaled, without occasioning any sensible change in the platina. 2. Three ounces of a mixture of 2 parts decrepitated sea-salt, and 3 parts of vitriol highly calcined, were pressed smooth into a cru- cible ; an ounce of platina spread evenly on the surface, and covered with some more of the mixture ; the crucible closely luted, and kept in a moderate red heat for several hours. On examining it when cold, the saline mixture was found to have melted, and formed a smooth, uniform lump. The platina, which had sunk to the bottom, being separated from the mixture by washing, proved of the same appearance as at first, though a little deficient in weight. 3. The experiment was repeated with what is called the regal cement, a less fusible mixture, composed of common salt and colcothar each one part, and 4 parts of powdered red bricks. An oz. of platina, surrounded, as above, with 6 oz. of this composition, and cemented in a close-luted crucible with a red heat, for 20 hourSj'was still found unaltered in appearance, though there was some deficiency, as before, in the weight. Remark. — The marine acid, when thus detained in the fire by the combina- tion of other bodies, till strongly heated, and then set at liberty in the form of fume, dissolves or corrodes all the known metallic substances, gold alone ex- cepted. As the platina, in these experiments, retained its original polished surface, without any mark of corrosion ; it was presumed, that this mineral likewise had resisted the marine fumes ; and that the deficiency was owing to some of the smaller grains having been washed oft', along with the ponderous colcothar or metallic matter of the vitriol ; an accident not easily avoided. 4. Platina was therefore treated with mercury-sublimate, a combination of the highly-concentrated marine acid with a volatile substance, which in a proper de- gree of heat it readily forsakes, to unite with other metallic bodies. An oz. of platina was spread on 3 oz. of powdered sublimate ; the glass covered, and set in sand : after a moderate fire for some hours, the sublimate was found to have entirely arisen, Jeaving the platina of its original weight, as well as appearance. 5. Fifty grains of a mixture of one part of platina and 2 of gold, well nealed, and cautiously hammered into a thin plate, were surrounded with regal cement, the vessel covered, closely luted, and kept for a considerable time in a red heat. On examining the metal, it was found to retain the whiteness and brittleness, which gold constantly receives from so large a proportion of platina ; and to have lost in weight about 4- gr. or -i^j- part. Remark. — The loss here appears to have proceeded, not from the platina, but from alloy in the gold employed, which was above standard, but not perfectly fine : for the metal cemented a second time, with fresh mixture, sufitred no VOL. XLVm.] PHILOSOPHICAL TRANSACTIONS. 501 further diminution. If the marine acid were capable of dissolving platina, in- stead of -rh-s-^ nearly ^ would have been exeded. This experiment therefore determines, with certainty, the resistance of platina to the marine fumes ; and that the regal cement, so called from its being supposed to purify gold from all heterogeneous metallic matters, is incapable of separating platina from it.* •' Exper. 3. — Platina ivilh the Nitrous Acid. 1. Spirit of nitre diluted with water, proof aqua fortis, and the strong nitrous spirit, were digested separately, with -J- their weight of platina, in a gentle heat, for several hours. During the digestion, some bubbles were observed, as if a solution was beginning ; but the liquors acquired no colour ; and the platina, washed and dried, was found to have neither altered its appearance, nor lost of its weight. The fire being after- wards increased, and the acid spirits kept strongly boiling till they had entirely evaporated, no change could be observed in the platina. 2. Platina was like- wise treated with nitrous mixtures, by processes similar to those in which it had been exposed to the marine fumes. After cementation for many hours, in a red heat, with a mixture of 3 parts calcined vitriol, and 2 of melted nitre, the grains were recovered not only unaltered, but without any deficiency in weight. Remark. — From these experiments it is plain, that platina, equally with gold, re- sists the force of the vitriolic, marine, and nitrous acids, though applied in such a manner, as to be capable of perfectly dissolving all other known metallic bodies. Exper. A. — Platina ivith Aqua Regia. 1. Aqua regia,-}- which perfectly dis- solved gold, poured on platina, began to act on it in the cold, and, by the as- sistance of a moderate heat, slowly dissolved it ; acquiring at first a yellow colour, which deepened by degrees, as the menstruum became more saturated, into a dark brownish red. A few drops of the saturated solution tinged a large quantity of water of a fine golden colour. 2. The experiment was several times repeated with different aqua; regiae, made by dissolving sea-salt and sal ammoniac, separately, in 4 times their weight of aqua fortis ; and by abstracting the nitrous spirit from the same proportion of each of the salts. With all these menstrua the solution seemed to succeed equally. 3. In order to determine the quantity of menstruum necessary for the solu- tion ; 3 oz. of an extremely strong aqua regia, diluted with water, were poured on one oz. of platina, in a retort, to which was adapted a recipient. A gentle heat being applied, the menstruum acted violently, and red fumes arose in abun- dance. When about \ of the liquor had come over, the action was scarcely, if at all, sensible, though the fire was considerably raised. The distilled liquor, which appeared of a light redish colour, being poured back again into the retort, • When these experiments were made, the marine acid in its oxygenized state (oxymuriatic acid) was unknown. The metal of platina, called phtinum, is soluble in that preparation of the marine acid. t Termed in the New Chemical Nomenclature, nitromuriatic acid. 502 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. the solution began afresh ; the vapour, which now came over, appeared pale, compared with the first. The cohobation was repeated 4 times, the distilled liquor proving paler and paler every time. At length, both the fumes and action ceased, though the fire was raised, and a considerable part of the platina remained undissolved. The solution was therefore poured off, some more of the men- struum added, the distillation and cohobation renewed, and this occasionally repeated, till the whole was taken up, excepting a little blackish matter, of which hereafter. The quantity of strong aqua regia, employed for dissolving the oz. of platina, was 5 oz. ; but the last parcels appeared from their yellow colour not to be fully saturated, and on trial were found to take up near 50 grs. of fresh platina. Remark. It appeared, that by this method of managing the process, 1 part of platina was soluble in about 4i of aqua regia : but that when the digestion was performed in open vessels in the common manner, and the fumes, which arise copiously during all metallic solutions, suffered to exhale, more than half as much again of the menstruum was requisite. This process might therefore possibly be applicable to advantage, in making solutions of metals in the way of business. Examination of Solution of Platina. Exper. ] . — As the vitriolic acid carries down metallic bodies, gold not ex- cepted, from their solutions in other menstrua ; this acid was mixed with solu- tions of platina. 1. When the solution of platina was previously diluted with water; the addition of dephlegmated spirit of vitriol occasioned no precipitation, or change of colour, though a large quantity of the acid was, at different times, dropped in, and the mixture suffered to stand for several days. 2. Dephlegmated spirit of vitriol, added to an undiluted solution of platina, immediately rendered it turbid, and threw down a dusky-coloured precipitate. The precipitate was not re-dissolved on the affusion of water ; nor was the pre- cipitation prevented by adding water immediately after the acid had been dropped in. Exper. 2. — Solutions of platina, evaporated by a gentle warmth, to a proper pitch, and then set to shoot, yielded crystals, of a dark, almost opaqvie, red colour, in form of leaves, like flowers of benzoin, but thicker. The crystals, washed with proof spirit, became somewhat paler, but still remained of a high colour, resembling the deeper chives of saffron. Exposed to the fire, they seemed to melt, emitted white fumes, and at length fell into a dusky ash-coloured calx. Exper. 3. — Solutions of platina, dropped on hot marble, immediately cor- roded it ; but did not, like solutions of gold and some other metals, communi- cate any colour. Nor did they give any stain to the skin, to feathers, ivory, or other like animal substances, which liquors containing gold tinge purple. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 503 Exper. A. — As a minute proportion of gold contained in liquors is discoverable by their striking a purple colour with tin, 1 . Some bright plates of pure tin were put into a solution of platina diluted with water. The plates, in a little time, looked of a dark olive colour, and soon after were covered with a reddish brown matter : the liquor became at first darker coloured, and afterwards by degrees, as the precipitate fell, nearly colour- less ; without exhibiting the least appearance of a purplish hue. 2. Platina was digested in a quantity of aqua regia insufficient to dissolve the whole ; and the residuum dissolved in a fresh parcel of the menstruum. The two solutions, treated as above, yielded somewhat different phenomena, but no tendency to a purplish cast could be perceived in either. The latter, which looked yellow from not being fully saturated, was, when diluted with water, almost colourless. Yet, on the addition of the tin, it became yellow again, then red, and at length of a dark brownish red considerably deeper than the other more saturated solution. On standing for some time, it grew perfectly clear, depositing a paler, yellowish precipitate. 3. To determine whether platina was capable of preventing a small proportion of gold from discovering itself on this trial, one drop of a solution of gold was let fall into several ounces of a solution of platina diluted with water. On add- ing some plates of tin, the whole became immediately of a fine purple. Remark. It may be proper to observe, that in these kinds of experiments, plates of tin are far more eligible than the solutions of tin usually employed : for the solutions fail of striking a purple colour with solution of pure gold, unless certain circumstances are observed, which are not easily hit upon ; but tin in substance constantly succeeds, and requires no particular precaution. Exper. 5. As gold is revived from its solutions by inflammable spirits, the metal gradually arising to the surface, in form of a bright yellow cuticle ; 1. A solution of platina was mixed with a large proportion of highly-rectified spirit of wine, and exposed for many days to the sun, in a wide-mouthed glass, slightly covered with paper, so as to keep out dust. There was no appearance of any yellow skin ; nor any other alteration, than that the platina had begun to crystallize from the evaporation of the fluid. 2. A drop or two of a solution of gold being added to a large quantity of a mixture of solution of platina and spirit of wine, and the whole exposed as above to the sun ; a goklen film was in a few days observed on the surface. Remark. It follows from this experiment, and the foregoing one with tin,, that platina contains no gold ; and that it cannot, any more than the common metallic or other soluble substances, prevent a small proportion of gold mixed with it from being discoverable. 504 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. Exper. 6. — 1 . The spirits of sal ammoniac, prepared both by quicklime and by fixed alkaline salts, added to solutions of platina diluted with distilled water, precipitated a fine red sparkling powder ; which, exsiccated, and exposed to the fire in an iron ladle, became blackish ; without at all fulminating, which calces of gold, prepared in the same manner, do violently. On washing some of this precipitate on a filter, by repeated affusions of water, the greatest part of it dis- solved ; only a small quantity of a blackish matter remaining, and the liquor passing through of a deep, bright, golden colour. A very large quantity of the fluid was tinged of this colour by a small one of the powder. 1. Salt of wormwood, fixed nitre, the lixivium saponarium of the Lond. Pharmacopceia, precipitated a powder similar to the foregoing, except that its colour was less brilliant. 3. Sal ammoniac likewise, one of the ingredients, to which the menstruum owed its power of dissolving the platina at first, precipitated great part of it in form of a similar powder. 4. The liquors remaining after all these precipitations with saline substances, appeared of a yellow colour, almost as deep as before the precipitation. Fixed and volatile alkalies being added alternately, the liquor still continued yellow : but either of them, added after sal ammoniac had performed its office, threw down a fresh precipitate, which left the liquor colourless. 5. The addition of tin likewise, after either of the salts separately had thrown down all they were capable of doing, occasioned a fresh and complete precipita- tion ; provided a little more of the menstruum was dropt in, to enable the liquor to act on the metal. Exper. 7 • As gold is totally precipitated by alkaline salts, but platina only in part ; and as a minute portion of platina, remaining dissolved, tinges a surpri- singly large quantity of the fluid of a yellow colour ; it was presumed, that a small admixture of platina with gold might by this means be readily discoverable. A few drops of a solution of platina were therefore mixed with above 100 times the quantity of a solution of gold ; the whole diluted with water ; and a pure alkaline salt gradually added, as long as it occasioned any effervescence or preci- pitation. The remaining liquor was of so deep a yellow colour, that it was judged the platina would have discovered itself, though its proportion had been less than 1000th part of that of the gold. Exper. 8. — 1. Zinc, which totally precipitates all the other known metallic bodies, put into a diluted solution of platina, was very quickly acted on, and threw down a blackish calx. The liquor in good measure preserved its yellow colour ; a n ark that part of the platina remained suspended. 2. Iron, wnicn precipitates all the metals from their solutions, except zinc. ▼OL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 505' threw down a similar calx. It could not be judged by the eye, whether the pre- cipitation was complete, the solutions of iron and platina nearly agreeing with each other in colour. 3. Copper, the precipitant of mercury and gold, readily threw down platina from its solution, in form of a greyish calx, which was found on trial to retain a notable quantity of the copper. The liquor remaining after the platina had fallen, was of a more dusky green than solutions of pure copper, probably from its retaining some of the platina. 4. Mercury, which precipitates gold alone from aqua regia, put into a diluted solution of platina, seemed in a little time to be divided, and did not run freely. Soon after, it appeared covered with a greyish matter, which at first was appre- hended to be a precipitate, but was found afterwards to be a part of the mer- cury corroded. On applying a moderate heat, the whole of the quicksilver, the quantity of which was very considerable, was dissolved, without any precipitation. The experiment was repeated with a larger quantity of mercury than the solu- tion was capable of taking up. The platina now gradually fell down among the undissolved quicksilver, in form of a dark brownish powder ; leaving the liquor nearly colourless. 5. A solution of gold mingled uniformly with a solution of platina, without occasioning any turbidness or precipitation. The mixture, diluted with water, and sufFerwl to stand for some time, threw up a bright golden pellicle to the surface. Exper. g. — 1. A solution of platina, super-impregnated with as much mer- cury as it was capable of taking up, on being evaporated a little, so as to dis- pose it to shoot, yielded crystals not at all like those of platina, but in form of spicula, externally of a yellowish hue. These, slightly washed with proof spirit, became colourless. Exposed to the fire, they emitted copious white fumes, with a hissing or crackling noise ; and left a very small quantity of a reddish powder. 2. A mixture of solutions of gold and platina, being treated in the same manner, ruby-coloured crystals were obtained, which appeared to be chiefly gold, with very little of the platina. Remark. It seems therefore, that mercury and gold crystallize from their solutions before platina, leaving the greatest part of that mineral dissolved. This affair, particularly with regard to gold, deserves further inquiry. Exper. 10. — As the calces of metals, obtained by precipitation from acids, or by other means, vitrify along with frit or glass, and tinge them of various colours ; and as this process is recommended by some for investigating the nature of unknown metallic bodies ; the following trials were made with precipitates of platina. 1 . Half an ounce of a precipitate thrown down from solution of platina by> VOL. X. 3 T 506 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. plates of pure tin, was triturated an an iron mortar with 8 times its quantity of common white glass, the mixture put into a crucible, which was closely luted, and placeid in a wind furnace. The fire was gradually raised, and kept up ex- tremely strong for about 10 hours; when, the crucible being taken out and broken, the matter appeared of a dark blackish colour, untransparent, easily friable; interspersed with a bright whitish matter, apparently metallic. Remark. It is probable, that this metallic matter was the platina; and that the glass owed its opacity and dark colour, not to this mineral, but to the tin in the precipitate, some particles of iron abraded from the mortar, or other ac- cidental causes. 2. A quarter of an ounce of a precipitate of platina, made by alkaline salt, was ground in a glass mortar with 12 times its weight of white glass; and com- mitted to the same fire as the foregoing. The result was a compact, cloudy glass, pretty transparent in thin pieces, covered in part with a thin whitish coat. Towards the upper part, and all round the sides, were observed several particles of metal; which appeared to the eye like bright platina, and proved hard to the point of a knife. Remark. Nor does the glass here seem to have received any thing from the platina; the change being no other than what white glass is found to undergo from a slight impregnation with inflammable matter. General Remarks. It appears from the experiments related in this paper, that platina, like gold, is not acted on by the simple acids,* which dissolve every known metallic body besides; that aquae regiae, the solvents of gold, prove like- wise menstrua for platina; and that consequently the common methods of assay- ing or purifying gold by aquafortis, aqua regis, or the regal cement, can no longer be depended on; that it differs from gold, in giving no stain to the solid parts of animals, not striking a purple colour with tin, not being revived from its solutions by inflammable spirits, not being totally precipitable by alkaline salts; that in certain circumstances it throws out gold from its solutions; that these properties afford means of distinguishing a small proportion of gold mixed with a large one of platina, or a small proportion of platina with a large one of gold; and that platina contains no gold, excepting the few particles distinguished by the eye; that platina is precipitated from its solutions by the vitriolic acid, and by the metallic substances, which precipitated gold, though scarcely totally by any; and that its precipitates resist vitrification, and this perhaps in a more per- fect manner than precipitates of gold itself. PAPER III. The two former papers have given an account of the habitus or relation • As mentioned in a former note, it is soluble in the oxyrauriatic acid. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 507 of platina to the principal substances which act on metallic bodies; and shown that it is a simple metal, of a particular kind, essentially distinct from all those hitherto known, though possessed of some properties generally supposed peculiar to gold. Many of its distinguishing characters have been already pointed out; others will result from combining it with the several metals; with each of which, notwithstanding its resistance to the most intense fires by itself, or with unmetallic additions, it melts perfectly; occasioning remarkable alterations in their colour, texture, and hardness. Art. 1. — Platina with Tin. 1 . Equal parts of platina and pure tin were injected into a mixture of black flux and common salt in strong fusion ; and urged with a quick fire, in a good blast furnace. After a few minutes the whole appeared perfectly melted; and on being instantly poured out, ran freely along a narrow mould, forming a smooth ingot, nearly of the same weight with the platina and tin employed. The compound proved extremely brittle, breaking easily from a fall; internally it appeared of a close and smooth, though uneven surface; and of a dark grey colour. By the file, or a knife, it was readily scraped into a blackish dust. 2. One part of platina and two of tin, covered with a black flux, borax, and common salt, were melted in a wind furnace : the platina appeared perfectly taken up by the tin, soon after the fire had been raised to a light white heat. The ingot was found deficient in weight about Vf- It greatly resembled the foregoing, being only a little less brittle, and of a somewhat lighter colour. 3. One ounce of platina and 4 of tin, covered with black flux and common salt, and urged with a quick fire, melted together without loss. This compound yielded a little to gentle strokes of a flat hammer, but was by no means tough. It broke in pieces from a rude blow, and was still readily scraped into dust by a knife. The surface of the fracture was rough and granulated. 4. One part of platina and 8 of tin, injected into a fluid mixture of black flux and common salt, united, without loss, into a pretty tough compound; which bore to be considerably flattened under the hammer without breaking, cut smooth with a thin chissel, and shaved with a knife. Broken, it appeared of a sparkling, dark coloured, coarse grained texture. 5. One part of platina and 12 of tin, treated in the same manner, formed a mixture tolerably ductile; but still of a dull, dark hue, and a rough coarse grain, though somewhat less so than the preceding. 6. A mixture of 1 part of platina and 24 of tin, proved not much stifl^er than tin. The colour was whiter, and the grain finer and evener than those of the preceding compositions ; though in both respects it fell considerably short of pure tin. 7. Several of these compositions, covered with black flux, vvhicli hiid been 3x2 Platina. Platina 1, tin 1 Platina 1, tin 2. . . . Platina 1, tin 4 Platina 1, tin 8 Platina 1, tin 12 Platina 1, tin 24. . . . Tin By calculation. DiflFerence. . . 12.090 . 1.263 . 10.354 . . 1.481 .. 9.144.... . . 1.350 . . 8.271 . . 0.566 . . 7.935 . . 0.322 . . 7.573..,. .0.102 508 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. previously melted, were exposed in crucibles closely luted, to a strong fire in a wind furnace, which was steadily kept up for 8 hours. When taken out, they were all found to have suffered some diminution, amounting to about -^ of the tin. In appearance and quality, there was no sensible alteration, except that the mixture seemed more uniform, and the grain a little finer. 8. The remarkable gravity of platina induced us to examine the several mix- tures hydrostatically. Here it was found, that the specific weight of the com- pound constantly turned out less than the medium of the gravities of the two ingredients; and generally the more so, as the proportion of the platina was the greater. Specific graTity. By experiment. 17.000 10.827. .. 8.972... 7.794... 7.705. . . 7.613.., 7.471... 7.180. Remarkn. It appears from the foregoing experiments, that platina melts with at least equal its weight of tin ; that it destroys the malleability of near 4 times its weight: that with larger proportions it forms compounds tolerably ductile, but renders the texture of the tin coarser, and debases its colour. The difference in colour of these compositions was much less conspicuous on the touchstone, than when the fractures of the ingots were examined; though, on close inspection, they appeared all sensibly duller and darker than pure tin, and the more so, in proportion as the platina prevailed. They all tarnished in the air; those least, which had a very small or a very large proportion of platina. It is remarkable, that though tin is a metal very readily destructible by fire, yet in most of the preceding fusions, there was scarcely any sensible loss of weight. This is to be attributed not solely to the admixture of the platina, but also to the flux made use of, and more particularly to the celerity and short con- tinuance of the heat. In N° 2 and 7, the only ones in which the loss was at all considerable, the fire was slowly raised, and long continued. jirt. 2. — Patina with Lead. 1 . Equal parts of platina and lead were injected -into a mixture of black flux and common salt, previously melted together; and the fire hastily raised by bellows. A much stronger heat was requisite than for the fusion of platina with an equal quantity of tin; and the loss was considerably greater, amounting to about -^. The metal yielded difficultly to the file; broke. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. SOQ by a moderate blow, of a close texture, uneven surface, and rough jagged edges; tlie colour was very dark, with a faint purplish cast. 2. One part of platina and 2 of lead, covered with borax and black flux, and exposed to a gradual fire, in a wind furnace, did not come into fusion till the fire had been raised to a strong white heat : from the continuance of heat in this ex- periment the loss was great, being nearly -^ of the mixture. The ingot proved hard and brittle, like the preceding, but broke with a striated surface. 3. One ounce of platina and 3 of lead, treated in the same manner, required still a very strong fire for their perfect fusion: and lost about Vt* The metal broke less easily than either of the preceding, and in some measure yielded to the hammer: the colour was somewhat darker, and inclined more to purplish. 4. One part of platina and 4 of lead, being covered with black flux and com- mon salt, and committed to a wind furnace, the platina was not perfectly taken up, till the fire had been raised to a considerably strong white heat; the loss was -,1^. The same proportions of the metals, injected into a fluid mixture of the flux and salt, previously brought to the above degree of heat, almost instantly melted, and lost only -tb-o- The ingot was much tougher than the foregoing, filed well, and cut tolerably smooth with a knife. On breaking, the upper part appeared composed of bright plates, the lower of dark purplish grains. 5. One part of platina and 8 of lead united easily in a quick fire, and lost little or nothing. The metal worked and looked like very bad lead; on breaking, the texture appeared partly composed of transverse fibres, and partly of grains; the colour dull and purplish. 6. One part of platina and 12 of lead united, without loss, into a compound very little difl^erent from the foregoing. On breaking, its texture was somewhat finer, and composed chiefly of fibres, with very few grains. 7. A mixture of 1 part of platina and 24 of lead proved not very much harder than lead of a middling quality. The colour was still somewhat purplish, and the texture fibrous ; but the fibres were remarkably finer than where the platina was in larger proportion. 8. The foregoing compositions, when newly polished, appeared in general of a dark iron colour; which, on exposure to the air, quickly tarnished to a brownish yellow, a deep purplish, and at length a blackish. They all filed freely, without sticking in the teeth of the file, as lead does by itself. 9. On returning these compounds to the fire a second time, it was constantly observed, that after they had come into perfect fusion, if the heat was slackened a little, great part of the platina subsided; that ne\ertheless, the lead decanted off^, even in a heat below ignition, retained so much of the platina, as rendered it of a fine fibrous texture, and purplish colour. The several mixtures, covered with black flux, and kept in strong fusion, in 510 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. crucibles closely luted, for 8 hours, suffered a diminution in weight, amounting to about -jV of the lead. On breaking, those with a large proportion of platina appeared of a leafy, and those with a smaller, of a fine fibrous texture, which seemed in general to be characteristics of the perfect union of the platina and lead. They all looked whiter and brighter than at first, but tarnished sooner in the air. One mixture in particular, of 4 oz. of platina and 12 of lead, broke into large, white, bright, shining, talc-like flakes; which, on exposure to the air, changed in a little time to a reddish, a purple, and a deep blue; and at length turned slowly to a dark blackish colour. 10. On examining these compounds hydrostatically, their gravities turned out less than they ought to have been according to their calculation, but not so much less as those of the compositions of platina and tin. Specific gravity. By experiment. By calculatiou. Difference. Platina 17.OOO Platina 1, lead 1 14.029 14.193 O.164 Platina 1, lead 2 1 2.925 13.257 0.332 Platina 1, lead 4 12.404 12.509 0.105 Platina 1, lead 8 1 1-947 12.OO9 O.062 Platina 1, lead 12 11.774 11.818 0.044 Platina 1, lead 24 11.575 II.610. .... .0.035 Lead 11.386. Remark. It appears, that a small proportion of platina is taken up and kept suspended by lead, in a very gentle heat ; but that a large proportion is not taken up near so easily as by tin ; and if united by a strong fire, subsides in part on its abatement. A little quantity stiffens and hardens lead more than it does tin ; but a large one does not near so much diminish its malleability. A leafy or fibrous texture, a purplish colour, or disposition to acquire this colour in the air are peculiar to the mixtures with lead. yirt. 3. — Platina with Silver. 1. Equal parts of platina and of pure silver revived from luna cornea, covered with a borax, and urged with a strong fire in a blast furnace, melted perfectly together, and without loss, but did not run freely along the mould. The ingot was hard to the file, and broke by a rude blow; though by gentle strokes it bore to be considerably flattened. Internally it appeared of a much duller and darker colour than silver, and of a coarser texture. 2. One part of platina and 2 of silver, covered with nitre and common salt did not flow thin till the fire was raised to a very strong white heat. The com- pound proved less brittle than the foregoing, and not so hard to the file: the texture was composed of smaller grains, and the colour whiter. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 511 3. One part of platina and 3 of silver still required a very strong fire for their perfect fusion ; the metal was hard and brittle, though less so than the preceding: when well and repeatedly nealed, it bore to be hammered, or flattened between steel rollers, into thin plates. 4. One part of platina and 7 of silver melted together with ease. This com- pound hammered tolerably well, proved much harder than silver, and not so white, or of so fine a grain. 5. These compositions, weighed hydrostatically, turned out like the others, a little lighter than by calculation; but the difference, which before seemed to in- crease with the platina, was here greatest when the platina was in least pro- portion. Specific gravity. By experiment. By calculation. Difference. Platina 17.OOO Platina 1, silver 1 13,535 IS.ggO 0.455 Platina 1, silver 1 12.452 12.987 0.535 Platina 1, silver 3 11.790 12.485 O.695 Platina 1, silver 7 IO.867 11 .732 0.865 Silver IO.98O. , Remark. Platina appears to unite more difficultly with silver than with either of the foregoing metals. Even when the proportion of the platina is small, the greatest part of it subsides on an abatement of the heat, by which the union had been effected. This was prevented by pouring out the metal, when perfectly fluid, at one jet, into a broad mould: in which the compound began to congeal before the platina could separate. Platina diminishes the malleability of silver far less than that of tin or lead; and does not, in whatever proportion employed, so much debase its colour, or dispose it to tarnish in the air. Art. 4. — Platina ivith Gold. 1 . Equal parts of platina and gold, exposed to an intense fire, melted perfectly together, and ran thin into a long mould, with- out loss. The metal was of a white colour, hard to the file, broke by a rude blow, but when well nealed, yielded considerably to the hammer. 2. One part of platina and 4 of gold came into fusion in a moderate fire, but still required a very strong one for their perfect union. This compound appeared but a little paler than standard gold with silver alloy; and proved so tough, as to be beaten, with proper care, into thin plates, without breaking or cracking about the edges. On melting it a second time with nitre and borax, it became very pale, and was not without great difficulty made to recover its colour. yirt. 5. — Platina wit/i Copper. 1. Equal parts of platina and copper, exposed, without addition, to a strong fire hastily excited by bellows, soon became fluid 6ia PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. but not thin; and lost about ^. The metal proved extremely hard to the file; broke difficultly on the anvil ; flew asunder on endeavouring to cut it with a chissel ; and appeared internally of a coarse grained texture and white colour. 2. One ounce of platina and 2 of copper, urged with a quick fire in a blast furnace, without addition, flowed sufficiently thin, and scarcely suffered any sensible loss. The metal was still very hard, and yielded but little to the hammer. It looked darker coloured than the foregoing, with a slight reddish cast. 3. One ounce of platina and 4 of copper, treated in the same manner, united, without loss, into a pretty tough compound ; which bore to be considerably flat- tened, cut with a chissel, and bent almost double before it cracked. Internally, it looked of a fine texture, and a very pale copper colour. 4. A mixture of 1 oz. of platina and 5 of copper, stretched somewhat more easily under the hammer than the preceding; and appeared of a redder colour. 5. On increasing the copper to 8 times the quantity of the platina, the com- pound proved sufficiently tough, broke difficultly, and hammered well. It was much harder than copper, and of a paler colour. 6. A mixture of 1 part of platina and 12 of copper was somewhat more easily extended under the hammer than the foregoing, and proved softer to the file. It stuck a little in the teeth of the file, which the compositions with a larger proportion of platina did not. 7. A mixture of 1 part of platina and 25 of copper was still a little paler co- loured than pure copper, and considerably harder and stiffer, though very malle- able. On increasing the copper a little further, the mixture retained a degree of hardness, and appeared of a fine rose colour. 8. On weighing the foregoing compositions hydrostatically, the diminution of gravity was found more regular than in the mixtures with other metals, being constantly greater in proportion as the quantity of platina was larger. Specific gravity. By experiment. By calculation. DifFerenc©. Platina 1, iia .... copper 1.. . . 1 / .\j\j\j 11.400. .. .. . 12.915 .. , ,. 1.515 Platina 1, copper 2 10.410. . . ... 11.553., . ... 1.143 Platina 1, copper 4 9-908. . . . . . 10,464. . . . ..0.556 Platina 1, copper 5 9,693. . . ... 10.191,,. . . . 0.498 Platina 1, copper 8 9.300. . . ... 9.738.,. . . , 0.438 Platina 1, copper 12 9.251... . . . 9,458. . . 0.207 Platina 1, copper 25 8.970. . . .,, 9.144.,, ...0,174 Copper . . 8.830. Remark. In the i foregoing fusions, though in general no i flux was made use of, there was scarcely any j sensible loss of weight, unless in N° 1, where the VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 513 large proportion of platina required the fire to be raised to a violent degree. Thig seems owing, in good measure, to the platina preventing the scorification of the cop})er; for on melting pure copper a great number of times, both with and without fluxes, there was constantly a little loss. A small proportion of platina appears to improve the hardness of copper, without injuring its colour, or, so far as could be judged, its malleability. The mixtures with a large proportion of platina are difficultly extended under the hammer when cold; and while red- hot, fiy in pieces. They all bear a good polish, and do not tarnish in the air so much, or so soon, as pure copper. Art. 6. — Platina with Iron. Iron, the last of the metals in point of fusibility, was several times attempted to be united with platina, in its perfect malleable state. But as the fluxes necessary for rendering forged iron fusible corroded the crucibles, before the metal flowed thin enough to dissolve the platina, pure cast iron was substituted. 1 . Cast iron and platina, of each 3 oz. exposed without addition to a strong fire, united into a thick fluid; which, on adding an ounce more of iron, flowed thin, the compound suffered to cool in the crucible (which had become too soft from the heat to admit of its being poured out) was found, on breaking the vessel, in one lump, not convex, the form, which the iron usually assumes, but of a very concave surface ; the weight about -gV less than that of the metals em- ployed. It proved excessively hard, so as not to be touched by the file; and so tough, as not to be broken by repeated blows of a sledge hammer, from which it received some impression. Heated red, it broke easily, and looked internally of a uniform texture, composed not of bright plates like the iron at first, but of very dark-coloured grains. 1. One ounce of platina being injected on 4 of cast iron beginning to melt, and the fire kept up strong, the whole came quickly into fusion, and on cooling, formed an equable compound, which like the former proved extremely hard, and seemed to stretch a little under the great hammer without breaking. The colour was still very dark, though less so than when the platina was in larger proportion. 3. One part of platina and 12 of iron melted without difficulty, and with little or no loss. This compound was still much harder than the iron at first, and had a very considerable degi'ee of toughness. Like the others, it could not be broken while cold, without extreme violence; but proved very brittle when heated red. 4. The foregoing compositions, especially those in which the proportion of platina was large, received a fine polish ; and did not rust or tarnish on being exposed to the air in a dry room for several months. 5. A composition of 1 part of platina and 4 of iron was treated with sub- stances, which produce notable alterations in pure iron. Surrounded with VOL. X. 3 U 514 PHILOSOPHICA.L TRANSACTIONS. [aNNO 1754. Reaumur's steel making mixture (composed of charcoal powder, soot, wood- ashes, and common salt) and cemented in a close luted crucible for 12 hours, it gained an increase of -j'^ its weight, yielded to the file more easily than at first, seemed to receive no additional hardness on being ignited and quenched in water, and discovered none of the qualities of steel. A piece broken off from the same ingot, treated in the same manner, with the powder for softening cast iron (viz. bone-ash, with a small proportion of charcoal) was found increased in weight about -jVj proved less hard to the file than at first, but manifestly harder than the part cemented with the steel-making mixture. Specific gravity. By experiment. By calculation. Difference. Platina 1 7-000 PlatinaS, iron 4 9-917 11.343 1.426 Platina 3, iron 12 8. 700 9.O8O 0.380 PlatinaS, iron 16 8.202 8.663 O.461 Platina 3, iron 36 7. 800 7.862 O.062 Iron 7.100. General Remarks. — Platina melts with equal its weight of each of the metals; with one more readily than with another. With some it becomes fluid, if the proportion of the platina is not large, in a moderate fire; but a strong one is constantly requisite for its perfect solution. Compositions of silver, copper, lead, with about ^ their weight of platina which had flowed thin enough to run freely into the mould, and appeared to the eye perfectly mixed, on being digested in aquafortis till the menstruum ceased to act, left several grains of platina in their original form. On viewing these with a microscope, some appeared to have suf- fered no alteration ; others exhibited an infinite number of minute bright globular protuberances, as if they had just begun to melt. ' Platina hardens and stiffens all the metals ; one more than another, lead the most. In a moderate quantity it diminishes, and in a large one destroys, the toughness of all the malleable metals; but communicates some degree of this quality to cast iron. Tin bears much the least, and gold and silver the greatest quantity, without the loss of their malleability. A very small proportion of platina scarcely injures the colour of copper and gold: a larger renders both pale; a far less quantity has this effect on copper than on gold. It debases and darkens, in proportion to its quantity, the colour of the white metals; that of silver much the least, and of lead the most. It in good measure preserves iron and copper from tarnishing in the air; scarcely alters gold or silver in this respect; makes tin tarnish soon, and lead exceeding quickly. PAPER IV. — Platina mixed with Semimetals. 1. With mercury. 1, An VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 615 ounce of platina and 6 oz. of pure quicksilver were rubbed together, with a little common salt and water, and a few drops of spirit of salt, in an iron mortar. After some hours trituration, the grains of platina became coated with the quick- silver, so as to cohere into an imperfect amalgam. A part of the fluid quicksilver poured off, ami evaporated in an iron ladle, left a considerable quantity of a dark coloured powder, intermingled with bright shining moleculae: a part strained through leather, left a smaller proportion of a similar powder. The platina, which had been thus attenuated by the mercury, so as to pass with it through the pores of leather, proved as refractory in the fire as at first. Exposed to a very vehement heat, by itself, with borax, with white glass, it neither melted, nor suffered any sensible alteration; nor did it communicate any colour to either of the fluxes. 2. One part of platina and about 4 of lead were melted perfectly together; and after the heat had somewhat abated, poured gently into 3 times the quantity of quicksilver, heated so as to fume. A blackish powder was immediately thrown to the surface: this appeared to be chiefly platina. On grinding them together, a fresh powder gradually separated; which, being occasionally washed off, in appearance greatly resembled the foregoing, but was found, on proper trials, to participate much more largely of the mercury and lead than of platina. The amalgam, which was of a very dull colour, on exposure to the fire swelled and leaped about, though the heat was scarcely sufficient to evaporate the quick- silver. After constant and rapid agitation with water, occasionally renewed, in an iron mill, for a week, it looked bright and uniform, and suffered the mercury to exhale freely. A dark coloured calx remained, which proved, on examination, to be platina, with a very little lead. Remark. Mercury is supposed to have a greater aflinity with lead than any other metallic body, gold and silver excepted. In this experiment, it had a greater affinity with platina than with lead, since it retained most of the platina, after the lead, which was in much larger proportion, had been almost entirely thrown out. The part of the platina, which the mercury rejected at first, and that which it retained to the last, did not appear dissimilar to each other, or difterent in quality from the platina employed.* 3. A mixture of 1 part of platina and 2 of gold, which proved very white and brittle, after being repeatedly nealed, was cautiously flattened into thin plates, and thrown red-hot into boiling quicksilver. On trituration and ablution with water, a powder separated, copiously at first, and by degrees more sparingly. After the process had been contiimed about 24 hours, there was no further sepa- ration, except of a very little blackish matter, into which a part of the mercury • Concerning the action of mercury on platina [platinum] and the compound thence formed, see the interesting experiments of Mr. Chencvix in the Phil. Trans, for 1805. 3 u 2 5l6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. is always changed in these kinds of operations. The amalgam, which looked very bright, left, on evaporation, a spongy mass, of a high colour, which being melted, and poured into an ingot, proved very soft, extremely malleable, and in all respects resembled the pure gold made use of, without the least appearance of platina. Remark. — It is greatly to be wished that this method of purifying gold from platina may prove sufficiently accurate to exactly determine the quantity of each in the mixture. The experiments hitherto made do not sufficiently clear up this point ; a great number are still necessary before it can be fully ascertained. . 2. ff^ith Bismuth. — Equal parts of platina and bismuth, injected into a mix- ture of black flux and common salt, previously brought into fusion, and urged with a quick fire, strongly excited by bellows, melted perfectly in a few minutes, and suffered very little loss. Without these precautions, the bismuth could scarcely be made to take up above 4- its weight; great part of which, on an abate- ment of the heat, subsided. Mixtures of platina with different proportions of bismuth proved all, like the bismuth itself, extremely brittle : one was not remarkably more so than another. To the file, they were scarcely harder than pure bismuth. They broke of an irregular surface, composed chiefly of striae, with some plates. When newly broken, they looked bright and sparkling ; except the compositions with a large proportion of platina, which were of a dull greyish colour, without any bright- ness. They all tarnished slowly in the air, to a dark yellowish, purplish or bluish colour. Several acquired in part a fine deep blue, which has suffered no change in above a 12-month ; some parts of the masses still remaining white as at first, and others inclining to purple. 3. IVith Zinc. — On J oz. of platina, covered with borax, and heated in a blast furnace to a strong white heat, was injected an equal quantity of zinc. A violent deflagration arose, and the platina was almost instantly dissolved : the matter, immediately poured out, was found to have lost near half an ounce On several times repeating this experiment with different proportions of the 2 metals, both in a quick fire, and in 1 more gradually raised in a wind furnace, the zinc was constantly found a powerful menstruum for platina, but suffered great loss from the heat requisite for rendering the mixture sufficiently fluid. When so much of the zinc had been dissipated, that the remainder amounted to no more than -l of the platina, the compound still continued fluid enough to run freely into a long mould. Compositions of platina and zinc differed little in appearance from zinc itself; except that where the quantity of platina was large, they were of a closer texture, and a duller hue, with rather more of a bluish cast. They did not tarnish, or change their colour, on being exposed for several months to the air, in a dry VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 517 room. They were harder to the file than the zinc at first, and fell in pieces under the hammer ; without at all stretching ; which pure zinc does in a consi- derable degree. 4. TFith, Regulus of Antimony. — Regulus of antimony, the most difficultly flisible of the semimetals, dissolved, in a strong fire, equal its weight of platina. The compound looked of a much duller colour than the regulus at first ; and broke of a close and uniform, though uneven, surface. It proved considerably harder to the file, but not remarkably more or less brittle. On increasing the quantity of the regulus, the compound proved brighter, and of a leafy texture, little different from that of the pure regulus. Platina mixed ivilh Compound Metals. fVilh Brass. — 1. Equal parts of platina and brass, covered with borax, and Hrged with a quick fire in a blast furnace, melted perfectly together, and scarcely suffered any loss. The mixture was of a greyish white colour, filed hard like bell-metal, broken from a blow of the hammer, without stretching or receiving any impression, and flew asunder on endeavouring to cut it with a chissel. In- ternally, it appeared of a uniform fine grain, a close texture, and a darker colour than on the outside. It bore a very fine polish, and did not tarnish on being exposed to the air in a dry room for many months. 1. One part of platina and 1 of brass, melted in a slow fire, lost about -^. The ingot was of a duller colour than the foregoing, with a faint yellowish cast : it filed softer, broke less readily from the chissel, but cracked and fell in pieces under the hammer. 3. One part of platina, and 4 of brass, covered as before with borax, and ex- posed to a quick fire, melted without loss. This compound proved yellower than the preceding, filed softer, bore to be cut some depth with a chissel before it broke, and received some impression from the hammer, stretching a little, but soon cracking in various directions. 4. On increasing the brass to 6 times the weight of the platina, the compound appeared yellower, though still very pale. It proved softer to the file ; and re- ceived a greater impression from the hammer, and a deeper one from the chissel, before it broke. 5. A mixture of 1 part of platina and 12 of brass was considerably paler, and much harder, than brass. It broke from the chissel ; and cracked, before it had extended much, under the hammer. It bore a good polish, and was less apt to tarnish than brass ; though in both respects it fell short of the compositions with larger proportions of platina. IVith Copper and Tin. — 1. One hundred parts of platina, 34 of copper, and 12 of tin, covered with borax, became fluid in a strong fire, and suffered no considerable loss. The ingot proved extremely hard, so as scarcely to be touched 518 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. by the file ; and very brittle, breaking from a moderate blow, of a rough sur- face, and dull bell-metal colour. It bore a good polish, and did not tarnish in the air. 2. Platina and copper, of each 1 oz., and 4 oz. of tin, melted perfectly to- gether, and without loss. This compound filed freely and easily, bore to be cut with a knife, but broke readily on the anvil, of an irregular surface, and dull whitish colour. Polished, it looked like polished iron. The fracture soon tar- nished to a yellow; the polished part grew dull, but retained its colour. 3. A mixture of platina and copper, of each 1 part, and 8 of tin, proved softer than the foregoing ; and bore to be flattened a little under the hammer. It broke of a very irregular surface, composed of a great number of bright white plates. The fracture soon tarnished ; the polished part retained its colour. Remark. It is observable, that in the first of these experiments, platina was perfectly taken up by less than half its weight of a mixture of copper and tin ; though it could scarcely be made to melt with less than its own weight of either of them separately, in a fire equally, or rather more, intense. The specific gravity of these mixtures turned out, on exjjeriment, a little less than by calculation ; though the copper and tin, melted together without platina, formed a compound specifically heavier than even the copper by itself. The several mixtures with zinc, bismuth, regulus of antimony and brass, were likewise weighed hydrostatically, and found all somewhat lighter than they ought to have been by calculation. As few hydrostatical experiments seem to have been made on zinc and bismuth, it may be proper to mention, that the gravity of pure zinc turned out 7-050, and that of bismuth 9.733. Hitherto we have considered the miscibility of platina with metallic bodies, and the alterations which different proportions of it produce in their appearance and qualities : employing the necessary precautions for preventing the scorifica- tion and dissipation, which most of the metals suffer in the fire ; and which some remarkably promote in those which by themselves are more difficultly, or not at all, destructible. We shall now examine the relation of platina, in this respect, to those metallic substances, which are the most destructive. 1. Cupellation and Scorification of Lead with Platina. 1. A mixture of platina and lead was cupelled, under a muffie, in an assay- furnace. For some time the process went on well ; the lead gradually changing into scoriae, which were thrown off to the sides, and absorbed by the cupel, or dissipated in fume. In proportion as the lead worked off, the matter required a stronger fire to keep it fluid ; and at length, collecting into a dull flat lump, could no longer be made to flow in the greatest degree of heat which the fur- nace was capable of giving. The lump broke verj' easily, appeared of a dull grey VOL. XLVIIl.] PHILOSOPHICAL TRANSACTIONS. 51Q colour both internally and externally, and of a porous texture. It weighed about -}- more than the quantity of platina employed. '2. This experiment was many times repeated and varied : the lead attempted to be worked off on bone-ash, pressed into the bottoms of crucibles, scorified in assay-crucibles, by intense fires, in a blast furnace, and blown off on tests before the nose of a bellows, with the same event ; the platina not only perfectly resist- ing the power of lead, which by these operations destroys every other known me- tallic body, except gold and silver, but likewise retaining and preventing the scorification of a part of the lead itself. 3. In the history of the fusion of platina with lead, it has been observed, that this metal deposites in a gentle heat great part of the platina, which had been united with it by a strong one. As the part, which remained suspended, might be presumed to differ from that which subsided ; a quantity of lead was decanted off from fresh parcels of platina, and both the decanted metal and the residuum submitted to tlie preceding operations separately. The event was still the same; the matter becoming consistent when the lead had been worked off to a certain point, and refusing further scorification. 4. A mixture of platina and lead, which had been cupelled in an assay-furnace as long as it could be kept fluid, was exposed in a crucible to a fire vehemently excited, by itself, with powdered charcoal, with black fiux, borax, nitre, com- mon salt. The matter neither melted nor suffered any considerable alteration, becoming only somewhat more porous ; probably from a little of the lead having exsuded without the liquefaction of the mass. The immediate contact of burn- ing fuel, agitated by bellows, made some of these mixtures flow, after they had refused to melt in vessels acted on by intense fires. Very little of the lead was dissipated by this means. On examining the cupelled matters hydrostatically, those which appeared most spongy were found nearly as ponderous as the crude platina. Among the more compact, the gravity of one turned out 19.083 ; of another IQ.136, and of a third 19.240. Remark. It appears from these experiments, that platina, like gold and silverii is entirely indestructible by lead ; that probably the purer grains, or fragments, have some heterogeneous admixtures, which are separated in these operations ; and that, perfectly pure, it is more ponderous than gold, since, when mixed with a considerable proportion of a lighter metal, it fell very little short of the gravity of pure gold. There is no reason to suspect any increase of its specific gravity from the mixture ; since in all the compositions with platina hitherto examined, there was constantly a diminution of the specific gravity ; 'whether the proportion of the platina was large or small, the matter melted with a quick fire, or kept in fusion for many hours. ' 520 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. 6. A mixture of 1 part of platina and 3 of gold was cupelled with lead, under a muffle. The matter drove well for a considerable time ; at length it collected into a bright hemispherical lump, which by degrees became flatter, dull, and rough. The button, on being weighed, was found to retain a considerable portion of lead. The experiment being repeated with a mixture of 1 part of platina and 6 of gold, some part of the lead was still retained. The bead proved rounder and brighter than the foregoing, and of a good golden colour on the outside : it broke easily under the hammer, and appeared inteinally greyish : some of the fragments hung together by the outer golden coat. 7. Mixtures of platina and silver, submitted to cupellation, retained likewise a considerable quantity of the lead. These, in becoming consistent, formed, not a hemispherical bead, but a flat mass, very rough, and brittle, and of a dull grey colour both internally and externally. Cupellation and Scorification of Bismuth with Platina. Mixtures of platina with bismuth, a metallic substance, in some respects more active than lead, were cupelled under a muffle, scorified in assay -crucibles, tested before the nose of a bellows. In numerous repetitions of these experi- ments, the event was the same as when lead was made use of. ' The mixtures, which at first flowed easily, became less and less fusible, in proportion as the bismuth was driven off; and at length could not be kept fluid in an intense white heat, though they appeared, on weighing, to retain a considerable proportion of the bismuth. Nor could this semimetal, any more than lead, be entirely sepa- rated, by cupellation, from mixtures of platina with either gold or silver. Platina cupelled with bismuth, differed little in appearance from that which had been treated in the same manner with lead. The button was more spongy, and specifically lighter. 3. Difflation of Regulus of Antimony with Platina, A mixture of platina and regulus of antimony was melted, by a strong fire, in a shallow wide crucible, and the nose of a bellows directed obliquely on the sur- face. The matter continued to flow, and fume copiously, for some hours ; at length it became consistent in an intense white heat, and scarcely emitted any more fumes, though strongly blown on. The mass, when become cold, broke easily, appeared very porous, blebby, of a dull grey colour, and weighed consi- derably more than the quantity of platina employed. Platina was likewise treated with crude antimony : and the regulus obtained from this mixture, difflated as the foregoing, with the same event ; the platina ■not only resisting the antimonial semimetal, but likewise defending a part of it from the action of the fire and air, and refusing to melt, after a certain quantity had been dissipated. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 521 4. Deflagration of Zinc with Ptatina. A mixture of platina and zinc, exposed to a strong fire, deflagrated, and ap- peared in violent agitation. This continued but a little time ; the matter quickly became solid, and could no longer be made to flow; or the zinc, of which a considerable proportion remained in it, to flame. The mass was very brittle, dull-coloured, spongy, and of no specific gravity. General Remarks. This extraordinary mineral, on which the most active fluxes, assisted by the most intense fires, have no effect, melts perfectly with all the known metallic bodies ; unless arsenic, a substance impatient of a degree of heat sufficient to render itself fluid, is an exception.* All the metals take up equal their own weight ; some metallic compositions more than twice their weight. Platina appears in general to have no remarkable affinity with one metal more than with another. Lead and iron, which do not mingle together, and of which the former will take up some bodies from the latter, and the latter some from the former, seem both indifferent to platina; which, if combined with either, is not separated by the other. Yet some substances have greater or less degrees of affinity with platina, than with other metallic bodies. Thus, from aqua regia, in certain circumstances, it throws out gold ; and is itself precipitated by the other metals, which dissolve in that menstruum. From quicksilver it throws out lead ; and is itself thrown out by gold. The changes which platina occasions in the perfect metals, were examined in a former paper : its effects on the semi-metals are less I'cmarkable. The princi- pal are, that it increases the hardness of zinc, and the antimonial semimetal, but not of bismuth ; and disposes this last to change its colour in the air, but not the others. Its effects on the compound metals, are similar to those which it produces on the simple ones. Brass it renders white, hard, brittle, susceptible of a fine polish, and not liable to tarnish in the air, as it does the copper, and in Some degree the zinc, of which this metal is composed. Mixtures of it with copper and tin are more apt to tarnish than with copper only, and less than with tin only. All metallic substances, except gold, are exeded from platina by the simple acids : mercury is the only one separable by fire. The platina remaining after the separation of the metals, proves unfusible as at first. Platina perfectly resists the destructive power of lead and bismuth, and the * As mentioned in a former note, it may be brought into fusion when subjected to a suflScicnt degree of heat, with white arsenic, .^ , ., VOL. X. 3 X 522 PHILOSOPHICAL TRANSACTIONS. [aNNO 175-J. rapacious antimonial semimetal ; which last has been hitherto esteemed the severest test of gold, so as to have received the appellation of balneum solius solis, the bath which gold alone can sustain, and in which it is washed from all kinds of impurities. Since therefore platina mixed with gold is not discoverable by any of the ope- rations by which that metal is usually assayed or refined, nor by the hydrostatic balance ; Mr. L. hoped that these papers, which contain part of the history of this extraordinary and till then unknown mineral, and the methods of distin- guishing any sophistications of gold made by its means, which might otherwise have passed undiscovered, would be candidly received by the r. s. as a means of promoting that kind of knowledge, for which that illustrious body had been ever eminent,* LXXXVll, An Explication of all the Inscriptions in t/ie Pahnyrene Language and Character hitherto published. By the Rev. John Stvinton, M. A. of Christ- Church. Oxford, and F. R. S. p. 690. Mr. S. states in this learned dissertation, that on examining the plates ex- hibited in the magnificent work entitled the Ruins of Palmyra, he had, by the help of the Greek inscriptions, corresponding with those in thePalmyrene charac- ter, been able to make out the Palmyrene alphabet, which he makes appear from the accompanying tables, to which is added the alphabet of the same language, as given by Spon and Gruter. For the Palmyrene inscriptions themselves, with the interpretations and the comments on them, the philological and antiquarian reader is referred to the original Transactions, as they would not admit of abridgment, and would have occupied too much space had they been retained entire. See these alphabets and numerals engraven in pi. 14. LXXXVIIl. Extract of a Letter from John Lining, M.D. of Charlestown, in South Carolina, to Charles Pinckney, Esq. in London : with his Answers to several Queries sent to him concerning his Experiment of Electricity with a Kite. Dated Charlestown, Jan. i4, 1754. p. 757- Inclosed are answers to the queries sent me concerning the experiment with the kite. Since making that experiment last May, I have not had an opportu- nity of making any more, having been confined all the summer and autumn with the gout, which perhaps prevented my meeting with the same unhappy fate with Professor Richman of Petersburg. It appears that the professor had a wire, which came down from the iron rod, erected on his house, through the gallery- ceiling, to an iron bar, which stood in a glass vessel, filled with water and filings of brass ; and that the professor stood so near that iron rod, that his face was TOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 523 within a foot of it. Now if there was no wire that went from that iron rod, or from any part of the wire above it, into the earth, it is no great wonder that the professor was killed. I should be extremely glad to be informed, whether the iron rod on his house, at the time the experiment was made, had any comnmni- cation, by means of metal, with the earth. For if it had, there is then more danger attending these experiments than I imagined. It is likewise said in the account, that from the electrical needle, which he observed, there was no danger. I am at a loss to know what that electrical needle was, and should be glad to be informed. I know that a magnetic needle placed on a sharp point on the prime conductor, as soon as the conductor is sufficiently electrified, will move round with so great rapidity, that in the dark the electricity, thrown off from both poles of the needle, will appear like a circle of fire. Answers of Dr. Lining to the Queries sent to him. Query 1. In what manner, and of what materials, was your kite, and the string by which you flew it, made? and to what height did it rise above the earth ? Answer. The kite, which I used, was made in the common way; only, instead of paper, I covered it with a silk, called alamode. The line was a common small hempen one of 3 strands. A silk line, except it had been kept continually wet, would not conduct the electricity; and a wire, besides other inconveniencies, would have been too heavy. I had not any instrument, to take the height of the kite; but believe it was at least 250 feet high. It was flown in the day-time. Query 1. — You say also, " All the electrical fluid, or lightning, was drawn from the cloud, and discharged in the air; and a greater degree of serenity suc- ceeded, and no more of the awful noise of thunder, before expected, was heard." Now I should be glad you would inform us, whether the serenity in the air was such, as generally follows, after the clouds in the summer thunder-storms have discharged several loud thunder-claps ; and whether any flashes of lightning ap- peared in the skies, after you had discharged the cloud of its lightning by the kite, as commonly do after a thunder-storm is over in a summer's night ? for if there were no appearance of such flashes, then I think your assertion, that all the electric fluid or, lightning, was drawn from the cloud, stands fully proved ; but if there were such flashes after, I conceive there must have been some of the electrical matter left behind. Answer. — During the time of my drawing the lightning from the cloud, and for some little time afterwards, it rained; by which means, the body of the cloud being diminished, a greater degree of serenity necessarily succeeded ; and the quantity of lightning extracted from the cloud, or rather its atmosplicre, proveri 3x2 524 PHILOSOPHICAL TRANSACTIONS. [anNO 1754. sufficient to prevent any thunder in town that afternoon ; though there was a great appearance of thunder before the kite was raised. But whether the same serenity succeeded, as frequently happens after a thunder-storm, and whether there were any flashes of lightning seen in the evening, I cannot now recollect. If such flashes had afterwards been seen in the skies, as is common in a sum- mer's evening, especially after a thunder-storm, those might proceed from other clouds, which had passed the town, at too great a distance to be acted on by the kite. Electrified clouds have an electrical atmosphere, as well as the prime conduc- tor, when it is electrified ; and the diameter of that atmosphere, caeteris paribus, will. bear some proportion to the size of the cloud. My smallest prime conductor is 2-i- inches in diameter ; and when it is fully charged, its atmosphere extends to the distance of about 3 feet from the surface of the conductor. How great then must the extent be of the atmosphere, which surrounds a large cloud fully elec- trified ? It perhaps may extend to many hundreds of feet round the cloud, and may even reach so low as to touch the surface of the earth : and when that is the case, a man, or a rod of metal, placed on a cake of resin on the ground, may be electrified, and yield sparks of fire. When a sharp point is presented to that atmosphere, it cannot deprive the cloud of its whole quantity of electri- city, except the sharp point be so near, that the cloud may explode upon it ; and in that case the cloud must have a communication with the ground, by means of some non-electric body. Suppose an electrified cloud to have an at- mosphere, which extends round it to the distance of QO feet from its surface ; and let that atmosphere be divided into 3 parts, a, b, and c, each 30 feet in dia- meter: now if a sharp metalline point erected on a kite, or otherwise, be placed either vertically or horizontally in the most interior part of the atmosphere c, that point will continue to act till a quantity of the lightning is drawn ofF, equal to the quantity contained in that atmosphere, arid no longer. For then the semidiameter of the atmosphere being reduced to 6o feet, every part of it is above, and not in contact with, the sharp point, and consequently beyond its sphere of action. But let the sharp point be then advanced into the atmosphere B, and it will act as before, &c. The truth of this, however contradictory it may be, to the general opinion of the action of sharp points, in drawing oft" the electricity or lightning,* may be illustrated by the following experiments on the prime conductor. Electrify the prime conductor in a dark room, and draw back the globe to a sufficient distance from the prime-conductor, to prevent its being supplied with any more electri- * Mr. Franklin says, speaking of sharp points, " At whatever distance you see the light, you may draw off the electrical fire." page 2. — Orig. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 525 city from the globe, while you are taking ofF the electrical atmosphere with a sharp point. Bring then a sharp point, either vertically or horizontally, or in any other direction, within 1 feet of the prime conductor ; and the point, foi- some time, will appear luminous. After that light disappears, advance the point 3 or 4 inches nearer to the conductor, and you will observe the same phenomena as before ; and by advancing the point gradually in this manner, as the light on it disappears, the point will be alternately luminous and dark, till you have taken off the whole atmosphere in different laminae. As the point appears more and more luminous, the nearer that it approaches the prime-conductor, the electrical atmosphere may have different degrees of density, being perhaps denser near the prime-conductor, and rarer at a greater distance from it. If a phial be charged on the prime-conductor, when this experiment is made, the light on the sharp point will be much greater, and continue longer. Query 3. — Did you make any trial, at what distance you could kill an animal with a discharge of the electrical fluid from the key or the bottle suspended to it ? Answer. — I have not hitherto had an opportunity of making any such experi- ment with the kite. But as to the first, I apprehend, that no animal could be killed bv the discharge of any quantity of electricity accumulated on the key ; as the key in that experiment answers the same end as the prime-conductor, and, like it, is capable of receiving only a certain charge of electricity, except the lightning flows down the line too fast, or the kite be so near the cloud that it may explode, when one standing on the ground approaches the key to draw sparks from it : but such an explosion would probably be fatal to the operator. When a phial is suspended to the key, after it has received its charge, if you let it continue hanging on the key, the surcharge will fly off from the hook of the phial, and the phial, when charged in that manner, will not give a greater shock than if it had been charged in the common way with, the globe. LXXXIX. An Answer to Dr. Linings Query relating to the Death of Pro fessor Richman. By Mr. William, /Vatson, F. R. S. p. 7^5. Dr. Lining's letter of the 14th of January 1/54, being communicated to the Royal Society by Charles Pinckney, Esq. that learned body referred it to Mr. Watson, one of their members, in order that the best information, that could be procured on this subject, should be transmitted to Dr. Lining, for whose cor- respondence the Society had for many years had a very particular attention. Mr. Watson imagined, that it would be agreeable to Dr. Lining, as his abode is so remote from Petersburg, where the accident happened, to have transmitted to him not only the answer to what he more particularly requests, but also as general an account of every thing relating to so nncommon an accident, as could be procured. 526 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. The description of Professor Richman's apparatus, as sent by himself to Pro- fessor Heinsius of Leipsic, he called an electrical gnomon. To the construction of this gnomon were necessary a rod of metal, a glass jar, a linen thread of a foot and half in length, to one end of which was fastened half a grain of lead, and a quadrant. The rod of metal' cd, fig. 3, pi. 11, was placed in the glass vessel E, which contained filings of metal. The linen thread cg was fastened to the rod at c, and, when the apparatus is not electrized, hangs perpendicularly down. The radius of the quadrant, which was divided into degrees, was 2 lines more than a foot and half in length. And here must be added an account of the other part of the apparatus, which was to communicate the electricity to the gnomon during a thunder storm. Through a glass bottle, the bottom of which was perforated, passed an iron rod, which was kept in its place by means of a cork fitted to the mouth of this bottle, through which cork likewise was inserted the iron rod. A tile was removed from the top of the house ; and on this open- ing was placed the bottle, supported by the neighbouring tiles, in such manner that one end of the iron rod was not only 4 or 5 feet above the top of the house; but the other end, which came through the bottom of the bottle, did no where touch the tiles, or any other part of the house. To this end of the iron rod was fastened an iron chain, which was conducted into the chamber of Professor Richman, on electrics per se, so as no where to touch the building. The en- trance to this chamber faced the north ; and at the south end of it there was a window, near which stood a table 4 feet in height. On this the Professor placed his electrical gnomon, and connected it with the chain, which was brought under the ceiling of the room over this table, and communicated with the apparatus on the top of the house, by means of a wire bc, which hung from the chain, and was joined there to ab, by the little ring b, and communicated with the rod do at c. When the iron rod at the top of the house was affected by the thunder, or othei-wise suitable condition of the atmosphere, the thread before- mentioned deviated from the perpendicular; as it would also do, if artificially electrized. The Professor always observed a greater ascent of the thread from artificial elec- tricity than by that from the atmosphere. By the former, he had seen it on the quadrant describe an angle of above 55", but never above 30 by the latter. In the year 1752, Aug. Q, the apparatus acquired so great a degree of electricity from the atmosphere, that from the end of the rod the electrical flashes might be heard at several feet distance. Under these circumstances, if any one touched the apparatus, they felt a sharp stroke in their hand and arm. Professor Richman sometimes added to this apparatus a glass bottle of water, after the manner of Professor Muschenbroek hi, adapted to a vessel of metal ik, olaced on glass. The wire from the mouth of the bottle of water hl, during ihe time of the thunder, he caused to communicate with bc. From this addi- VOL. XLVIII.] I'HILOSOPHICAL TRANSACTIONS. 527 tion he found the electricity from the atmosphere more vehement than it was without it. This he first observed on May 31, 1753, when the electrical fire exploded with such a force, that it might be heard at the distance of 3 rooms from the apparatus. On the left hand of the bottle was placed a 2d electrical gnomon. When this was made use of, the wire of metal bo, and the wire hl, were connected with mbl, a prime conductor from an apparatus for artificial electricity, viz. a glass globe, &c. At the same time also, from the chain ab was fastened a piece of wire bk, in contact with the vessel ik. By these means, when the electrical machine was put in motion, both the electrical gnomons were electrized: but this went off^ in a great measure, as soon as the motion of the machine ceased. By this whole apparatus taken together, Professor Richman observed a kind of reciprocation in the effects of electricity ; for at first, when the electrical machine was put in motion, both the linen threads cg and cg arose with the degrees of their respective quadrants. If then the wire bc of the right gnomon was touched, the thread cg collapsed to the rod cd; but the thread on the left side continued diverging as before the touch. Also, if the wire bc of the left gnomon was touched, then in its turn the thread cg at the rod cd of the right gnomon collapsed, and the thread of the right gnomon ascended again. This reciprocation of the ascending and descending of the thread, might be repeated 3 or 4 times without exciting the machine anew. The ingenious and industrious Professor Richman lost his life on the 6th of August 1753, as he was observing, with Mr. Sokolow, engraver to the Royal Academy at Petersburg, the effects of electricity on his gnomon, during 3 thunder storm. As soon as his death was publicly known, it was imagined that the lightning was more particularly directed into his room by the means of his before-mentioned apparatus. And when this affair was more inquired into, this opinion appeared to be not ill-founded; for Mr. Sokolow saw that a globe of blue fire, as large as his fist, jumped from the rod of the right gnomon cd, to- wards the forehead of Professor Richman, who at that instant was at about a foot distance from the rod, observing the electrical index. This globe of firej which struck Professor Richman, was attended with a report as loud as that of a pistol. The metal wire bc was broken in pieces, and its fragments thrown on Mr. Sokolow's clothes, from their heat burnt marks of their dimensions on them. Half of the glass vessel e was broken off, and the filings of metal in it were thrown about the room. Hence it is plain, that the force of the lightning was collected on the right rod cd, which touched the filings of metal in the glass vessel E. On examining the effects of lightning in the Professor's chamber, they found the door-case split half through, and the door torn off, and thrown into the chamber. The lightning therefore seems to have continual its course along the chain, conducted under the ceiling of the room ; but tliat it came from the 528 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. apparatus at the top of the house to the door, and then into the chamber, does not, as far as can be collected, appear. If indeed it could be ascertained, that the lightning, which was the death of Professor Richman, was collected on the apparatus, for this reason, because these bodies, at the instant of the lightning, were capable of attracting and retaining the electricity, it would then be in our power sometimes to divert the effects of lightning. But of this fact, more time and longer experience must acquaint us with the truth. Hence Mr. Pinckney may acquaint Dr. Lining, that in Mr. Watson's opinion, at the time Professor Richman was killed, his apparatus was perfectly insulated, and had no communication with the earth, by the means of metallic or other substances, readily conducting electricity, and that the great quantity of electri- city, with which, from the vastness of the cause, the apparatus was replete, dis- charged itself through the Professor's body, being the nearest non-electric sub- stance in contact with the floor, and was unfortunately the cause of his death. This, it is presumed, would not have happened, had the chain, or any other part of the ap})aratus, touched the floor, by which the electricity would have been readily communicated to the earth. Since the reading of the above to the Royal Society, a treatise in Latin, inti- tled, Oratio de Meteoris vi Electrica Ortis, by Mr. Lomonosow, of the Royal Academy of Sciences at Petersburg, has been transmitted to the Society. By this, among many other curious facts, we have been informed of certain parti- culars in regard to the death of Professor Richman ; of which the following may not be improper to be inserted here. Mr. Lomonosow observes, that with regard to the sudden death of the gen- tleman before-mentioned, the accounts, communicated to the public, contained some circumstances not fairly stated, and others of some importance were en- tirely omitted. With regard to the first, it is incontestably true, that the win- dow, in the room where Professor Richman was, (a) fig. 6, had continued shut, that the wind might have no effect on his electrometer; but that the window in the next room (efdg) was open, and the door (d), between these two rooms, was half open; so that the draught of air might justly be suspected to have followed the direction of the iron conductor of the Professors apparatus; that this con- ductor came from the top of the house at (i), and was continued to (h) and (b). 2dly. That this conductor was not placed far from that door-case, part of which was torn off". 3dly. That at this time no use was made of the Leyden bottle, mentioned in the preceding account; but the iron was inserted into a glass stand, to prevent the dissipation of the electrical power, and that the gnomon should show its real strength. With regard to the 2d, there has as yet been no mention, that Professor VOL. XLViri.J PHILOSOPHICAL TRANSACTIONS. 529 Richinan, at the time of his death, had 70 rubles (a silver coin) in his left coat- pocket, which by this accident were not in the least altered. 2dly. That his clock, which stood at (f), in the corner of the next room, between the open window and the door, was stopped ; and that the ashes from the hearth (g) were thrown about the room. 3dly. That many persons without doors declared their having actually seen the lightning shoot from the cloud to the Professor's appa- ratus at the top of his house. A view is likewise added of the chamber, (fig. 7) where the Professor was struck by the lightning: who stood at (h), with his head projecting towards (g) his electrometer; at (m) stood Mr. Sokolow the en- graver; from the door (c) a piece was torn off, and carried to (d); (ab) part of the door-case rent. In this treatise Mr. Lomonosow, among other phenomena of electricity, takes notice, that he once saw, in a storm of thunder and lightning, brushes of elec- trical fire with a hissing noise, communicate between the iron rod of his appa- ratus and the side of his window; and that these were 3 feet in length, and a foot in breadth. Effects like these no one but himself has had the opportunity of observing. XC. Extract of a Letter from John Henry fVinhler, Professor of Natural Phi- losophy at Leipsic, and F. R. S. relating to two Electrical Experiments. Dated Leipsic, May 22, 1754. p. 772. On January 8, he sprinkled a plate of metal with the seeds of club-moss.* To this plate he connected a chain, which communicated with the coating of the Leyden bottle of water. He afterwards sufficiently electrized this water, to make the artificial thunder, of which he gave an account in his treatise De Avertendi Fulminis Artificio, p. 10 and 1 1. Having drawn these seeds together on a heap on the plate, he brought over them the sphere of metal, the size of which is" arbitrary, impregnated with this electricity. On bringing this sphere near the plate, the electricity exploded, by which the seeds were set all on fire. These seeds were dry, and had no inflammable spirit mixed with them. The flame which arose from these seeds was true fire, as it lighted some flax, which lay on. the seeds, and extended itself beyond the metal. Jan. 13 he put some aurum fulminans on a circular piece of parchment: this parchment he cemented to a plate of metal, and caused the bottle replete with electricity to be discharged on it. Immediately the aurum fulminans exploded with a very loud report, and the circle of parchment was torn all to pieces. • Lycopodium, club-moss, wolf's-claw. — Orig. VOL. Xw S Y 530 I'HILOSOPHICAL TKANSACTIONS. [aNNO 1754. XCl. Of a Fire-ball, seen at Hornsey. By H^tlliam Hirst, F. R.S. p. 773. This phenomenon Mr. H. saw on Feb. l6, \75A, about 5 minutes before 11 at night. He was then going down the hill adjoining to the south side of Hornsey church, and was not a little surprised to find himself suddenly sur- rounded with a light equal to that of the full moon, though the moon, which was theji 4 days old, had been set about 30 minutes. He had a distinct, though short, view of a ball of fire, which at first appeared to be about 15° high, w. by N. Its descent was not exactly perpendicular, but made an angle of about 80° with the s. s. w. part of the horizon, moving from left to right, so that when it went below the horizon, its bearing from him was w. n. w. It moved with great velocity, not continuing visible much longer than 2 seconds; though he did not lose sight of it till it descended below the horizon. But short as this duration was, its shape might be well discerned. The diameter of the nucleus, or head pf the meteor, appeared to be equal to the semidiameter of the meridional full moon, and the tail, which terminated in a point, seemed not longer than twice the diameter of the nucleus. And its track in descending seemed to be but about 10° from the vertical; as the position in fig. 8, pi. 11. This meteor was not attended with any noise, nor left any luminous stream after its descent below the horizon. The appearance of such meteors at that cold season of the year is the more extraordinary, as their generation is attributed to exhalations caused by heat, or the action of the sun ; for which reason they are generally seen after hot sultry weather. By the distinctness and red fiery colour of this phenomenon, he imagined that it was not very high in the atmosphere; but should be induced to think other- wise, if credit is given to an account from Dublin, which states that a like meteor was seen there between 10 and 11 that night, which illuminated the whole hemisphere, and continued about 4 seconds. The near agreement in these two accounts, as to the situation and time (allowing for the difl^erence between the meridians of Dublin and Hornsey), it being nearly half an hour past 10 at Dublin when 1 1 here, makes it very probable that it was one and the same me- teor; which, if so, is a proof that its height in the atmosphere must be very considerable. XCII. A Comparison between the Notions of M. de Courtivron and Mr. Melvil, concerning the Difference of Rcfrangibility of the Rays of Light. By Mons. Clairaut, Memb. of the R. Acad, of Sciences at Paris, and F.R.S. p. 776. M. Clairaut observes that both the above-named gentlemen, Mr. Melvil and Mr. de Courtivron (the former in a paper lately printed in these Transactions, and the latter in a book published by him in 1752) had thought of accounting vol,. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 531 for the difference of refrangibility, by the difference of velocity in the rays of light; which, if it really agreed with the observations, would give a great sim- plicity to the theory of refraction, as reducing it under the same laws as the theory of gravity; whereas on the hypothesis, in which the particles of light are endowed with tendencies different from each other, we are obliged to multiply the properties of matter. Messieurs de Courtivron and Melvil went so far the same ways, as to examine, whether the immersions and emersions of Jupiter's satellites could not afford the means of distinguishing the difference of velocities between the rays of several colours. In fact, if", according to that hypothesis, the red rays were swifter than the others, it possibly might happen that the satellite would appear of a reddish colour in the beginning of the emersion ; viz. before the full time required for the whole transmission of light from the satellite to us. As to the examination of the number of seconds between the propagation of the red and violet rays, the two authors differ widely; and M. Clairaut thinks, that Mr. de Courtivron's calculations are more surely grounded than the others. Mr. Melvil supposes, that the difference of velocity between two sorts of rays must be very nearly as the difference of their sines of refraction, when their sines of incidence are the same. Whence he concludes that, as the sine of refraction of the red rays is about y^ greater than the sine of refraction of the violet ones, the velocity of the first rays must also exceed the velocity of the second by about -Jy. He indeed gives those proportions as only being nearly the same; for, says he further, to know exactly the ratio of the velocities from the sines of refiac- tion, the following problem should be resolved, which he proposes to the learned: " If two bodies fall, in equal angles of incidence, on a space terminated by parallel planes, in which any power acts perpendicularly to the planes (according to the hypothesis in prop. Q4, lib. 1, of the Principia), the ratio of the sines of the emergence to the common sine of incidence, and consequently to each other, being given, to determine the proportion of their velocities at the time of their incidence on the first plane." But as the investigation of the curve described by the rays of light, in any hypothesis of attractive power, has been published long ago (at least by M. Claraut in 1738), and by such a method as leads to the solution of Mr. Mclvil's problem, he doubts not but if he had seen that method, he would have resolved the problem which he proposes, and perceived what a considerable difference there is between the proportion of the velocities, and that of the sines of refraction. M. de Courtivron, who has made use of M. Claraut's solution, arrive*! at the following result: If /; denote the ratio of the sines of incidence to the sine of refraction for one of the colours, and q the same ratio for any other, then y I — qq to \/ 1 — pp will express the ratio which the velocity of the first rays 3 Y 2 532 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. bears to t!ie velocity of the others. Now, to make use of such a theorem, if p and q be made equal to 4^ and -l-s., which are the proportions between the sines of incidence and refraction for the red and violet rays, the ratio of the velocities sought will come out in even numbers, that of 45 to 44, which differs entirely from Mr. Melvil's. Thus, if Mr. Short's observations have led him to conclude, from Mr. Melvil's principles, that the difference of refrangibility cannot be caused by the difference of velocities, when the motion of light is performed in the manner of a projectile, how surer may not his assertion be according to M. de Courtivron's calculation, since they give a difference of time considerably greater? XCIII. On some New Electrical Experiments. By John Canton, M. A., F.R.S. p. 780. The resinous and vitreous electricity of Mr. Du Fay, which arose from his observing bodies of the one class to attract, what those of the other would repel, when each were excited by attrition , received no light till the publication of the second part of Mr. Franklin's experiments ; where it appears, that the one kind of bodies electrify positively, and the other negatively; that excited glass throws out the electric fire, and excited sulphur drinks it in. But no reason has yet been assigned, why vitreous bodies should receive, and resinous bodies part with this file, by rubbing them. Some persons indeed, of considerable knowledge in these matters, have supposed the expansion of glass, when heated by friction, t© be the cause of its receiving more of the electric fluid than its natural share ; but this supposition cannot be made with regard to bodies of the other sort, such as sulphur, sealing-wax, &c. which part with it when treated in the same man- ner. The following experiments, first made at the latter end of December 1 753, and often repeated since, may perhaps cast new light on this difficult subject. Having rubbed a glass tube with a piece of thin sheet-lead and flower of emery mixed with water, till its transparency was entirely destroyed; after making it perfectly clean and dry, Mr. C. excited it with new flannel, and found it act in all respects like excited sulphur or sealing-wax. The electric fire seems to issue from the knuckle, or end of the finger, and to spread itself on the surface of this tube, in the beautiful manner represented at a and b in fig. 1, pi. 14. If this rough or unpolished tube, be excited by a piece of dry oiled silk, espe- cially when rubbed over with a little chalk or whiting, it will act like a glass tube with its natural polish. And in this case, the fire a}3pears only at the knuckle, or end of the finger; where it is very much condensed before it enters; as at A and b in fig. 2. But if the rough tube be greased all over with tallow from a candle, and as much as possible of it wiped off with a napkin, then the oiled silk will receive a VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 533 kind of polisli by rubbing it, and after a few strokes, will make the tube act in the same manner as when excited at first by flannel. The oiled silk, when covered with chalk or whiting, will make the greased rough tube act again like a polished one: but if the friction be continued till the rubber is become very smooth, the electric power will be changed to that of sul- phur, sealing-wax, &c. Thus may the positive and negative powers of electricity be produced at plea- sure, by altering the surfaces of the tube and rubber; according as the one or the other is most affected by the friction between them ; for if the polish be taken otf one half of the tube, the difterent powers may be excited with the same rubber at a single stroke. And the rubber is found to move much easier over the rough, than over the polished part of it. That polished glass electrizes positively, and rough glass rubbed with flannel negatively, seems plain, from the appearance of the light between the knuckle, or end of the finger, and the respective tubes; but yet may be further confirmed by observing that a polished glass tube, when excited by smooth oiled silk, if the hand be kept at least 3 inches from the top of the rubber, will at every stroke appear to throw out a great number of diverging pencils of electric fire, as in fig. 3 ; but not one was ever seen to accompany the rubbing of sulphur, sealing- wax, &c. nor was Mr. C. ever able to make any sensible alteration in the air of a room, merely by the friction of those bodies; whereas the glass tube, when excited so as to emit pencils, will, in a few minutes, electrify the air to such a degree that, after the tube is carried away, a pair of balls, about the size of the smallest peas, turned out of cork, or the pith of elder, and hung to a wire by linen threads of 6 inches long, will repel each other to the distance of 14^ inch, when held at arm's length in the middle of the room. But their repul- sion will decrejise as they are moved toward the floor, wainscot, or any of the furniture; and they will touch each other when brought within a small distance of any conductor. Some degree of this electric power sometimes continues in the air above an hour after the rubbing of the tube, when the weather is very dry. The electricity from the clouds, in the open air, may be discovered in the same manner, if the balls be held at a sufficient distance from buildings, trees, &c. as he had several times experienced, by a pair which he carried in a small narrow box with a sliding cover, fig. 4, so contrived as to keep their threads straight, and that they may be properly suspended, when let fall out of it ; and these balls will easily determine whether the electricity of the clouds or air be positive, by the decrease, or negative, by the increase of their repulsion, at the approach of excited amber or sealing-wax. To electrify the air, or moisture contained in it, negatively ; he supported by 034 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. silk, between two chairs placed back to back, at the distance of about 3 feet, a tin tube with a fine sewing needle at one end of it; and rubbed sulphur, sealing- wax, or the rough glass tube, as near as can be to the other end, for 3 or 4 minutes. Then will the air be found to be negatively electrical; and will con- tinue so a considerable time after the apparatus is removed into another room. The air without-doors is sometimes found to be electrical in clear weather ; but never at night, except when there has appeared an aurora borealis, and then but to a small degree. How far positive and negative electricity in the air. with a proper quantity of moisture between, to serve as a conductor, will account for this, and other meteors sometimes seen in a serene sky, he leaves to the curious in this part of natural philosophy to determine. That dry air at a great distance from the earth, if in an electric state, will continue so till it meets with such a conductor, seems probable from this experiment: an excited glass tube with its natural polish, being placed upright in the middle of a room, by putting one end of it in a hole made for that purpose in a block of wood, will generally lose its electricity in less than 6 minutes, by attracting to it a sufficient quantity of moisture, to conduct the electric fluid from all parts of its surface to the floor. But if, immediately after it is excited, it be placed in the same manner before a good fire, at the distance of about 2 feet, where no moisture will adhere to its surface, it will continue electrical a whole day, and how much longer he knows not. It may not be improper to mention here, that if a solid cylinder of glass be set before the fire till quite dry, it may as easily be excited as a glass tube, and will act like one in every respect; the first stroke will make it strongly electrical. XCIV. On the Ejects of Electricity in the County Hospital at Shrewsbury. By Cheney Hart, M.D. p. 786. They tried the effects of electricity in many different cases, though with little success, except in the case of one woman, whose left arm had been paralytic some years, and remained so, notwithstanding all the endeavours used to remedy it, so that it was absolutely motionless, and senseless of heat, cold, or pain. This patient had her arm electrized frequently, and the sparks were drawn from it, and the greatest blows given to it, for many days successively, by which in about 8 or 9 days time her arm grew sensible of pain and warmth, &c. and she had some little motion of her fingers, being able to grasp any thing with her arm down, or before her ; but she could not lift it up to her head any better. This encou- raged them to continue the electrizing 3 or 4 weeks longer; in which time she had got some little strength in her arm, could open and shut her fingers, and lift it half way to her head : but the pain she had from the electrizing, and the fear that increased continually of new shocks, made her obstinately resist using it any longer; and she chose, she said, rather to remain paralytic, than undergo VOL. XLVni.] PHILOSOPHICAL TRANSACTIONS. 535 such operations any more : so that she was discharged out of the Infirmary, with such little relief as above mentioned, and Dr. H. never has heard more of her. He wished she had tried it a while longer, as it bid so fair to do her service ; and this was the only case, which gave any reasonable hopes from its use. Another young girl, about l6, whose right arm was paralytic, on being elec- trized the 2d time, became universally paralytic, and remained so about a fort- night ; when the increased palsy was removed indeed by the medicines which her case indicated ; but the first diseased arm remained as before. However, notwithstanding the former bad accident, he had a mind to try the electricity on her again, which he renewed, and after about 3 or 4 days use, she became the 2d time universally paralytic, and even lost her voice and tongue, and with dif- ficulty could swallow : this confirmed him in opinion, that the electric shocks had occasioned these symptoms. He therefore omitted it, and the girl, though she got better of her additional palsy, remained as bad as before of her first ; and after about 4 months repeated course of medicines of different kinds on her, she was discharged incurable. These were the only 2 cases worth noticing, that had occurred, in which it could be said to have produced any remarkable eflTects at all : for on numbers of others, that had experienced it, Dr. H. observed nothing happen, except that when the affected palsied limb was touched with the electrical conductor, a con- vulsive motion was produced immediately ; but this was over very soon, and they had all remained as motionless and bad as before. XCV. On the Number of Inhabitants within the London Bills of Mortality. By the Rev. IVm. Brakenridge, D. D., F. R. S. p. 788. Dr. B. consulted the yearly bills of mortality for the last 50 years, viz. from 1704 to 1753, which he imagines sufficient for the purpose; and from them he extracted all the numbers of the baptisms and burials, both within the walls of London, and at large within the bills of mortality. And because it may be surer to compute from a number of years taken at an average, than from the numbers in any one year as they stand in the bills; he took the sums of the numbers, for each 3 years of the 50, and then the 5 th part of each of these sums : which will at a medium be the number for any particular year. And in like manner, he took the sums of the numbers for each 10 years, and the 10th part of each of the sums will be the number for any year, at an average. And the numbers so found appeared thus : 536 PHILOSOPHICAL TRANSACTIONS. [anno 1754 In the whole Bills of In the C ty only. Mortality. Years. Baptisms. Burials. Baptisms. Burials. 1704 to 8 1870 2553 15867 22103 ■ 1709—13 1805 2551 15288 21701 > 1714—18 1890 2706 17586 24641 ;; 1719—23 1871 2719 J 8360 26978 ci 1724—28 1829 2727 18442 27670 1729—33 1578 2532 17452 26267 1734—38 1406 2242 16762 26165 01 2 1739 — 43 1221 2397 15034 28219 1744—48 1062 1989 14402 23884 P 1749—53 1087 1790 14850 22006 . > 1703—13 1837 2552 15577 21602 " 1714 — 23 1880 2712 18073 25809 0 < 1724—33 1703 2647 17920 27168 3 3 1734 — 43 1313 2320 15898 27192 "S 1744—53 1074 1890 14626 22945 s. Where the numbers are ranged in 5 columns. The first denotes the years, the 2d and 3d the baptisms and burials within the city walls, and the 4th and 5th show the baptisms and burials at large within the bills. Thus, for instance, 22945 is the number of burials, at a medium, for any of the 10 years within the bills from 1744 to 1753 inclusive. And, in like manner, 1221 is the number of baptisms for any year, at an average for 5 years, from 1739 to 1743 inclusive, and so of others. The numbers above the line are computed for 5 years, and those below are for 10. In the burials, it is always to be considered, that there are perhaps 2000 more than what the bills represent them. For there are burying-grounds belonging to the Protestant Dissenters, the Quakers, and the Jews, that are very consi- derable, of which there is no account taken. In the first of which, in Bunyan- fields, he was informed there are about 400 burials in the year, and in the others together there may be about 400 more , which sum of 800 we may suppose comes from all parts within the bills. But Dr. B. thinks the one-half, viz. 400, must at least come from within the city, where there are most Protestant Dissenters and Jews. So that 400 may always be added to the burials, within the city. Also both from within and without the city, a great many burials go out into the country, of which no notice is taken. But if we were to suppose that there are 1200 in the whole, carried out into the country, over and above the 800 mentioned above, in the burying-grounds, he thinks that to be the outmost. And therefore in the calculations he supposes 2000 burials yearly, more than in the bills at large. It is next to be observed, that in the bills the baptisms are always about two- fifth parts, at least, less than the burials, with the numbers added to them above- mentioned ; and that this difference within the city seems continually to increase. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 53/ SO that it is much greater now, than it was some years ago ; which appears plainly to arise from two causes; the number of Dissenters of various denomina- tions, and the multitude of people that live unmarried. But he thinks it is rather owing to the last : for, in London and Westminster, the one-half of the people at least live single, that are above 2 1 years of age : which must prevent almost as many more births, that might be reasonably expected. And this is not mere conjecture; for he had some proof from a particular detail of one parish within the city ; where the greater part of those that are above that age are single. In the natural state of mankind, it seems plain that the number of births should be greater than the burials, and he believes that in many parishes in the country they are nearly double. He found it so in the Isle of Wight, where he lived some time, and had an opportunity to see their registers ; for there the births were generally nearly double. And even in London, b,efore the great fire in 1666, it appears, from some parish registers, that the baptisms were nearly about equal to the burials, but never afterwards : the reason of which he does not understand, unless it be that more people were then married, and that from that time there was a greater confluence of strangers : for there certainly were more dissenters at that time than ever after. It is further to be observed, that in the bills from the year 1704 to the year 1728, without the city, both the numbers of christenings and burials continually increased; and that from that time to 1743, they continued nearly the same; but that after 1743 they gradually decreased till this time ; which plainly shows, that the inhabitants were increasing till about the year 1728 ; and that from thence to 1743, they remained in the same state nearly ; but that afterwards, during the last 10 years, till 1753, they were constantly diminishing. For it is evident, that the number of inhabitants must always be in proportion, to the number of births, and burials considered together. And hence it appears, that the cities of London and Westminster were in the most flourishing state, with regard to numbers, from 1728 to 1743, and that they are now past their height, and in the same state they were in the year 17OS: and the first decrease seems to have been at the beginning of the last French war, which was in ] 744. Within the city walls the number of the inhabitants do not seem to fluctuate, in the same periods of time, as without ; for the most numerous state of the city, appears to have been from the year J 7 18, to the year 1728, and then after that they have been continually decreasing : so that when they were most numerous within the walls, they were not then arrived at the height without ; and when they were in the highest state without, they were diminishing in the city. Per- haps the vast number of new buildings, within the liberties of Westminster, may have in part caused this diminution. And as from the year 17 18, within the city, the christenings have been so remarkably decreasing, that they are now VOL. X. 3 Z 538 PHILOSOPHICAL TRANSACTIONS. [anNO 1754. but three-fifths of what they were at that time, and the burials are likewise di- minished above one-fourth in the last 5 years ; this seems to show, that the in- habitants within the city walls must be nearly one-fourth fewer, than they were in the year 17 18. Now, in order to calculate the number of inhabitants, it will be necessary to observe, that in a year in London there generally dies one person in 30. This Sir Wm. Petty has long ago observed ; and Dr. B. found it to be near the truth, on consulting his parish register. For in the parish of Bassishaw, London, there are not above 800 people, as appears from an account lately given him : and the burials for the last 10 years in the whole amount to 262 ; which at a medium gives 26 for one year, which is the 30th part of 800 nearly. In some parishes in London there die more than in this proportion, as in St. Giles's Cripplegate ; and in others in the out parts of the town there die fewer; but in general it will hold true, in and about the city. In the town of Breslaw in Germany, from which Dr. Halley formed his table for the probabilities of life, there die about 2 in 69, that is less than 1 in 34 ; as is plain from an easy computation. But there certainly die more than in that proportion, within the London bills ; for it appears that one-third at least of the children die under 2 years of age ; whereas at Breslaw there die under that age, only one-fifth ; and therefore the difference being two-fifteenths, or four-thirtieths, there die 4 in 30 more at London than at Breslaw, imder 2 years of age. In the country the case is very different ; for there does not die above 1 in 50, in healthy places. Sir Wm. Petty has also observed this. For in the parish of Newchurch in the Isle of Wight, where Dr. B. resided some time, there are about 900 people, and there does not die, at a medium, above 18 yearly ; which is one in 50 exactly. And he believes this will be found to be nearly the same in most of the counties in Britain, where the people do not live in great towns; which shows the great difference between the effects of the air in London and the country. K then it be allowed, that in London and Westminster there dies one in 30, it will be very easy to make a calculation of the whole number of the people nearly, that are within the bills. For if we take the number of burials at an average for some years, and multiply that by 30, the product must be the num- ber of the people. Thus if we take the number of the burials, at large within the bills, for any one of the last 10 years, at a medium, from 1744 to 1753 in- clusive, to be 22945, and add to this 2000, for those burials omitted in the bills, as is supposed above, the total will be 24g45, all the burials within the limits of the bills, for one year at 1753; and then multiply this by 30, the pro- duct 748350 will be the whole number of the people nearly, at present. But if we take 27 192, the number of the burials, at a medium, for any one of the ten VOL. XLVIII.3 PHILOSOPHICAL TRANSACTIONS. SSQ years preceding 1 743 inclusive, anci add to this 2000, as above ; the whole of the burials at that time within the bills will be 29 192, which being multiplied by 30 gives 875760, for the number of the people at the year 1743. And therefore tiie inhabitants are fewer now than they were in 1743, by 127000. If we were to try the same calculation, by taking the burials, at a medium, only for .5 years to 1753, and also for 5 years to 1743 inclusive, the difference will be greater. For the numbers at these two times will be 720180, and 906570, of which the difference is I8639O; so that the people would appear fewer at 1753 than they were in 1743, by I86000. But this is not so much to be depended on as the numbers above ; because there were two extraordinary bills at 1740 and 1741. Or if we should imagine that there might not more die at London than at Breslaw, that is 1 in 34, still the difference would be greater than we found at first. For taking the burials at an average for ten years, at 1753 and 1743, as above, the numbers would at these two times be 848130 and 992528, of which the difference is 144398 ; so that it seems plain, if the bills are to be depended on, that there is a decrease of the people since 1743 of above an hundred thousand, and that at present the number is about 740000. And this ^decrease has been annually continued : for if we try the thing further, at the distance of 5 years, and take at a medium for 5 years, the burials for 1753 and 1748, the numbers will come out 720180 and 776520 ; of which the difference is 56340, the number decreased for the last 5 years. There is another way of computing, from the number of houses ; but he thinks this not so certain as the other. For here are two difficulties ; to ascer- tain the number of houses, and to fix on the number of persons for each house. As to the last. Sir Wm. Petty thought we might allow 8 persons to a house: which Dr. B. found to be a mistake. He made an experiment of it, and got an exact account of the numbers in each house in a certain parish in London ; and he found that they exactly come to 6 in a house, empty and full together, for there is seldom above one in 20 empty. And as in that parish the people are in a middle condition, and some of them have a number of servants ; it may be presumed they are in a middle state with regard to numbers, between the very great families, and those in the lowest rank This is also confirmed, if we allow, as above, 1 in 30 to die yearly in London. For within the city walls there were 11857 houses in the 97 parishes, as appears from Mr. Smart's ac- count, which was supposed to be very accurate at that time: but since he published that in 1741, there are not so many houses within the city walls; for in many parishes there are houses greatly enlarged, some rebuilt instead of 2 or 3 ; and warehouses made of others. In some parishes there is 1 in 20 fewer than in his time. In others perhaps there is no alteration. But he thinks they must, at an average, be diminished 3 in 100 at least; and consequently there are about 354 3 z2 540 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. fewer, and the number of houses within the city walls is about 1 1 503 ; which being multiplied by 6, gives 690I8, for the number of inhabitants; which is nearly equal to the burials 22Q0 multiplied by 30, or 68700 ; taking the burials at a medium for 10 years, and adding 400 as above. The number of houses within the bills may then be nearly come at, from the number of burials. For if we take the number of burials for the last 10 years, at an average within the city, to be 1 8g0, and add 400, which makes 22Q0, we may say, if 229O comes from 11503 houses, then the whole number 24g45 of burials within the bills, having allowed 2000 as above, must come from 125302 houses. And there cannot be fewer ; for there are more burials within the city, in proportion to the baptisms, than in the out-parishes ; and therefore more burials in proportion to the number of houses ; which shows that the number of houses cannot be less than 125302; which being multiplied by 6, will give 75 18 12, for the number of people for this present time; and it is nearly equal to the number 748350 found above. So that the numbers produced from these 2 methods being almost equal, this is some further proof that our supposition, of 6 persons to a house, empty and full, is near the truth. But if we suppose, that the number of houses within the walls is now the same, as in Mr. Smart's time, 11857; then all the houses within the bills will be 129158, and the number of people 774948, greater than 748350, found above, by 26598; which is not much in such calculations. Sir Wm. Petty also says, that he was informed there were 84000 houses te- nanted within the bills, in the year l682, in which he wrote, and if so, the number of houses seem to be increased near one-third since that time. And, according to our way of computing, to suppose 6 to a house, empty and full, there could not be more than 504000 people at that time ; which is less than the number we found above, for the present time, 748350, by 244350. But now, instead of increasing, we are decreasing; for since the year 1743 the in- habitants have been annually diminished; by which it appears that this great city is past its height, and is rather on the decline with regard to numbers. And hence we see how far Sir William was mistaken, who imagined that it might increase continually till the year 1800; when the number of people would be 5 millions, that is near 7 times as much as they are at present. Now, to account for this decrease, there may be various conjectures : Dr. B. thinks 3 causes may be assigned, that may all operate jointly. One may be the vicious custom that has prevailed of late years, among the lower people, of drink- ing spirituous liquors ; another the fashionable humour of living single that daily increases ; and a third may be the great increase of trade in the northern parts of Britain, that keeps the people there employed at home, that they have no occasion, as formerly, to come hither for business ; and it were to be wished VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 541 that this cause was the most prevailing. But whatever be the cause, it seems plain, that it could not be the late French war, as some imagine. For, by what was shown above, there has been a decrease of 56000 since the year 1749, after the peace ; but if the war had been the cause, there ought rather to have been an increase after it. And as in the whole, we could not have lost more than 150000 in the war, by land and sea, of which there was not one-fifth, or 30000, taken from about the city ; this can never account for 64000, the decrease before the year 1748. In the former war, between 1702 and 1711, the city never de- creased, but continually increased : from which one would imagine that the last war could not diminish its numbers. Nor can this decrease in the bills be accounted for, from a greater number than formerly leaving the town in summer ; because it does not appear that there is a greater number of such, than was 1 0 years ago. And if it could be allowed that the number was greater, it can never be thought that it can amount to 120000 more than in the year 1743. • It is true, this decrease may appear surprizing to some, when they see the number of new buildings in Westminster, continually increasing ; but then, on the other hand, it is likewise to be considered, that there are a great number of houses enlarged, or rebuilt, instead of 2 or 3 others, as mentioned above ; and others falling in and empty, about the eastern parts of the city : so that for the last 20 years the inhabitants seem only to be moving, from the eastern to the western parts of the town, and not increasing. XCVI. On a large Calculus found in a Mare. By Mr. JVm. Watson, F, R. S. p. 800. This stone was composed of different laminae, and its figure is that of an ob- late spheroid, whose greatest diameter is 84- inches ; its lesser 8 inches. Its surface is extremely regular, but it appears in several of its parts, as though it had been corroded by some acrid menstruum ; and in a place or two, where the external lamina is quite worn away, and the lamina immediately underneath it polished during its continuance in the mare, the calculus has great resemblance in colour to occidental bezoar. It weighed in air 15 lb. 12 oz. Avoirdupois ; in water 6 lb. : so that its specific gravity to that of water was nearly as 8 to 5. So that it is not only considerably lighter than any fossil petrifaction, but much more so than many animal ; some human calculi, when fresh extracted, being to water as 2 to 1. With regard to its bulk, it is the largest he remembered to have been ob- served, except one presented to the r. s. in the year 1737, which was taken out of the stomach of a dray-horse, belonging to Sir Henry Hickes, Knt. at Dept- ford, and which weighed 1 9 lb. Avoirdupois, exclusive of the outward shell or 543 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. crust, which was broken off in several pieces. Both these stones were in ap- pearance like a pebble, and formed of different laminae. The greatest circum- ference of the stone taken from this mare was somewhat more than 26 inches ; that of Sir Henry Hickes's 28. Sir Henry Hickes's horse was 22 years old ; and, for 11 or 12 years before he died, frequently was observed to be in vio'ent pain ; but the mare, the subject of the present letter, though 1 6 years old, gave no signs of being in pain till about 3 months before her death, when she would frequently lie down, and roll about. And it is the more extraordinary that, large as the stone was, it did not disable the mare from doing her usual work for a more considerable time before her death ; which did not seem to be occasioned by the stone, she dying near her foaling time ; nor so far disturb her economy, as to prevent her propagating her species. In 1746, the Duke of Richmond presented to the Society a stone found in the colon of a horse, the circumference of which was 16 inches. His Grace at the same time presented some other stones, found in the intestines of a mare, which were polished like bezoar. It was very remarkable, that 2 of these stones, when sawed asunder, were found to have been formed each on an iron nail, as a nucleus. XCFII. On the Belemnites* By Mr. Guslavm Blander, F.R.S. p. 803. The belemnites is a fossil, that has hitherto perplexed the naturalists of all countries : it has been treated of by various authors, and differently ascribed to all the 3 kingdoms of nature ; but Mr. B. delivers it as his opinion, that it be- longs to the testaceous part of the animal kingdom, and to the family of the nautili. The nautilus, or sailor, is a concamerated shell, with a syphunculus running through every cell, see pi. 14, fig. 5. The syphunculus, and the concamerations, are the generical character of this tribe, and are supposed to serve the animal to buoy up its shell, by which means it can swim or sink at pleasure. Those that are curved are very common, both in the recent and fossil state ; the straight ones have hitherto only been met with fossil, and are common in Sweden, Livonia, and several parts of Germany ; and have, by naturalists, been called orthoceratitae ; and Mr. B had seen some in Dr. Mason's private collec- tion at Cambridge, which he said were found at Whitby in England ; the cha- * The belemnites is in all probability a species of nautilus, and its inhabitant may be allied to that of other nautili ; and consequently resemble in some degree a sepia or cuttle, which by the older writers was often called a polypus. Linneus imagined it a petrifaction of the Alcyonium Lyncurium. Mr. Brander's notion of the testaceous tribe in general having proceeded from polypes, can only have Arisen from bis want of zoological information. VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 543 racter of which being exactly the same with the nautili, Mr. B. makes no scruple to class them together. Whoever will examine nicely bodies of any genera, will have a difficulty to say, where they begin, and where they end ; the gradation is so insensible that they must be bewildered. From the orthoceratitfe, which is doubtless a species of nautilus, we gradually proceed to the belemnites. The orthoceratites is a straight concamerated shell, ending in a point ; some of which are seen in stone 18 inches long. See fig. 6, 7, 8, Q, and l6. The nucleus, or al- veolus of the belemnites, is likewise a straight concamerated shell or body, exactly resembling the other in shape and structure, but of a smaller species, fig. 10 and 14 ; and, from the very great analogy, may reasonably be deemed to be of the same family. In the conic cavity of the belemnites, fig. 1 1 , that con- tains the nucleus, it is very common to observe visible marks of a shelly sub- stance, as a further confirmation that the nucleus was a testaceous body. And now a word as to the belemnites itself, the counter part to the other. It has indeed been truly matter of speculation, how that huge solid substance called the belemnites, exclusive of the nucleus, could be formed ; and how it happens that some should have the nucleus within them, others not ; the cavity to contain the same in some very small, in others scarcely or not at all visible. These are the main difliculties, all which Mr. B. endeavours to elucidate; but first acknowledges his obligation to Mons. de Peysoimel, and particularly to Mr. John Ellis, f.r.s. for their curious observations on the nature of coral, on which this latter part of Mr. B.'s hypothesis is founded. They have plainly demon- strated, that many bodies which we always took to be vegetable from their ap- pearance, are really animal, and constructed by the polype ; and that several co- ralline substances, hitherto reputed marine plants, are thick beset with a prodi- gious quantity of seedling-shells, too small for the naked eye to see, close by each other, as diamonds in a bodkin, ready to come forth in due time out of their several nests or cellules ; see Phil. Trans, vol. xlvii, p. 445, and vol. xlviii. p. 115. Hence he submits, if it is not highly probable that the testaceous tribe in general are generated like butterflies, and flies of all kinds, the one from a mag- got, the other from a polype } Nay, it appears presumptive, that it must be so with a great many. On which circumstance he proceeds, that as corals in ge- neral, from late observation, seem to be constructed by polypi, what inconsistency then to believe them to be the primary state of all or most of the testaceous tribe? If so, it is almost beyond a conjecture, that the body called a bclenmites (which, on being put into acids, is found to ferment in like manner as coral, and other cretaceous bodies), is formed likewise by a polype, I'rom which tlie nucleus seems to be the ultimate state. 544 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. And he further submits, whether this concamerated shell, or body, of which the belemnites is only the habitation, does not appear a strong voucher for this new hypothesis, by more immediately leading us into the connexion and manner of generation (perhaps particular to the testaceous tribe) by remaining within its nidus all its life ; whereas they generally quit them as soon as they are able to shift for themselves. The polype is an animal of the vermicular kind ; the bodies of some are long and slender, like a fine sinew or fibre, extremely tender ; and from the head proceeds a variety of claws, or arms, with which it catches its food, and prepares its habitation or chrysalis. They are without doubt of various shapes and tex- tures, according, as he supposes, to the species of the animal that is hereafter to proceed from them ; and very wonderful it is, how so small, so delicate an ani- mal, should be capable of forming so large a body as the belemnites ! but is not every particular performance of nature equally the same to a diligent inquirer ? Some animals in the terrestrial part of the creation, naturally associate and herd together. Others again seek solitude. The same dispositions we find impressed on those of the aquatic system : then why not among the polypi ? as is evidently seen by the prodigious variety of coral bodies, where it seems in some as if thou- sands acted in concert together; in others, where each acts for itself; of which latter is the belemnites. The shape of the belemnites is generally more or less conical, terminating in a point, and of various colours, according to the juices of the stratum in which it lay : it has usually a seam or fissure, running down the whole length of it, sometimes filled with a cretaceous substance. In some it is in the middle or axis of the body ; in others on one side. Its interior constitution seems composed of several conoid cortices, or crusts, which, when broken transversely, appear to proceed in striae or rays from the seam or centre ; which seam he takes to have been the habitation or cell of the animal in its polype state, and in which the body was affixed ; or perhaps serving as a syphunculus, in which was a ligament that proceeded from the nucleus in its perfect state. The crusts it is composed of probably denote certain periods in the age of the animal; as the annual rings in a piece of timber, its age: but what those periods are, we are not acquainted with ; see fig. 11, 12, 13, 15. The animals of the testaceous tribe in general, as they increase in age, increase their shell in thickness till they have lived their stated time, or attained to good old age ; and that is done by adding a new crust or lamina to it, as several, if not all the tubuli, the oysters, and the nautili, witness ; after which they become inactive and dull, the effect of extreme old age, suffering other marine bodies, as worms, oysters, &c. to penetrate and affix themselves to their outer coat. The like appearances we VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 345 frequently meet with on belemnitae, when the animal within was perhaps either waxed old, or was dead ; and is an additional proof that the body is of marine origin. Every one, who has made this part of natural history his study, must have observed, that the minutiae, or exceedingly small fossil shells, very frequently occur, and in the greatest abundance, especially in fine loam or clay proper to presei-ve them : which shows that it was spring or spawning-time when the de- luge overwhelmed the country they were natives of. And that diminishes one of the difficulties concerning the belemnites, why some have the cavity, others not, or but very small : for may we not attribute these several appearances to the dif- ferent ages of the animal ; as in the spring or spawning-time, and some time after, a thousand small fish appear in the water to one grown to maturity, or seedlings on the shores of shell-fish, to one at full growth ? and, from a parity of reasoning, is there not great likelihood to believe that every belemnites would have had a nucleus, if it had lived ; and to suppose that deficiency to be caused by the deluge coming on, in the early part of the season, in that spot where they are natives, before they had attained perfection ? The country of the belemnitae is unknown to us ; but there is great probability it is the same with that of the conchae anomiae in general, and ammonitae; since they are usually found together, and are well supposed to be the inhabitants of deep or unknown seas, beyond human reach. Having had so frequent occasion to mention the orthoceratitae in the course of this subject, they being here rare and uncommon fossils, Mr. B. has given the figures of some (ew species of them, which perhaps may not be unacceptable, N" 6, 7, 8, 9, 1 6. If it should be asked, whether they proceed likewise from a belemnites ? he answers, that he supposes them to proceed from a polype like the rest, but whether their parent polype formed itself a belemnites-like chrysalis or habitation, being a stouter animal, is more than he can affirm, though very probable, as the terminating point in them is as sharp and fine as the nucleus of the belemnites ; and it is observed, that all the turbinated shells increase their circumvolutions from the point or apex ; but that is not the immediate business of the present purpose, as nature has many ways to compass her ends. His de- sign will be answered, if it shall only be thought, that he has evinced the be- lemnites to be an animal production, formed by a polype, as other coralline bodies ; and its nucleus to be a concamerated testaceous bcxly, of the nautili genus, proceeding from it. Description of the Plate 14. Fig. 5. A section of a common nautilus. 6, 7, 9. l6, Sections of ortho- ceratitae. 8. An orthoceratites entire. 10. A section of a belemnites, with the nucleus. 11. Ditto, without the nucleus. 12. An oblique section of a belem- VOL. X, 4 A 346 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. nites, to show the inner structure. 1 3. A belemnites without a cavity, only a small perforation. ]4. A nucleus of a belemnites. 15. A belemnites, with a very small cavity. XCnil. On the Jgaric, applied after imputations, with Regard to deter- mining its Species. By Mr. William Watson, F. R.S. p. 811. The agaric applied as a styptic after amputations, and which had been brought from France, Mr. W. did not believe to be the common agaric of the oak, as had been imagined by the French surgeons. What is called the com- mon agaric is a parasitical plant, found growing on the oak, and on several other trees; and is denominated by Caspar Bauhin, fungus in caudicibus nascens, unguis equini figura ; of which touchwood or spunk, and the amadoue ordinaire of the French, is usually prepared. He 'thought it impossible, by any process, to prepare from the common agaric a substance perfectly similar to the French agaric, which should exactly answer the description, which Breynius (Ephem, Nat. Curios. Ann. 45, obs. 130) gives of the fungus coriaceus quercinus haematodes. Mr. Ray, in his Synopsis Stirpium Britann. on the authority of the late Dr. Sherard, says, that this fungus coriaceus quercinus haematodes is found on putrid oaks in Ireland, where it is called oak-leather; and that the country people there collect and preserve \\. to dress ulcers with. Dr. S. makes no doubt but that it may be found in England; and Mr. Ray had some sent him from the late Dr. Eales in Hertfordshire. Dr. Richardson, in Yorkshire, found it growing on the ash ; and Dr. Dillenius observes, that in Virginia it is used as leather, to spread plasters on; and that, besides its being a soft substance, sitting easy on the af- flicted part, it has a healing property. XCIX. Ttvo Letters concerning the Use of y^garic, as a Styptic. Letter 1. — From Mr. J. Warner, F. R. S. and Surgeon to Guy's Hospital, p. 813. In the first of these letters Mr. W. states that he had received from Mr. Fellowes, an account of the styptic effects of the agaric, in a case under the <^re of Mr. Gooch, and that he (Mr. Warner) had contiimed to use the same application with the greatest success. Letter 2. — Addressed to Mr. Warner by Mr. B. Gooch. — After returning thanks for the agaric of the oak, which he had received by Mr. Fellowes, the writer of this letter proceeds to give an account of the effects he had observed from it. Two or 3 days after Mr. G. received it, he was desired by an ingenious surgeon to be with him on business. He carried some of the agaric with him, and he was pleased with the opportunity of trying it in an amputation below the knee of a boy of about 10 years old. They applied it according to the direc- YOL. XLVIII.] , PHILOSOPHICAL TRANSACTIONS. 347 tioiis given by Mr. Warner in his book, and the haemorrhage was entirely stopped in 6 minutes. He informed him that, on the 5th day inchisive, the dressings and agaric came all off without force, and left the stump in a good digested state, without the least appearance of blood; and that the pain, in con- sequence of the operation, did not require an anodyne. He cut a boy for the stone the same day, and a vessel bleeding rather more than is thought allowable, he applied a very small piece of the agaric, and a soft dossil of lint over it, which, with gentle pressure of the finger, restrained the bleeding in less than a minute. His own patient, aged near 70, on whom he made trial of it, in am- putating his leg below the knee, appeared as proper a subject to establish the credit of this new styptic as could be produced, if it failed not in its efficacy ; there being in him a great depravation of the fluids, and a general relaxation of the solids; and he had an ulcer on his leg, of the phagedagnic kind, of many years standing, attended with carious bones. Under these discouraging circum- stances he applied to Mr. G. about a month before, and begged of him to take off his leg; the pain, he said, being so violent and continual, that he knew not how to live with it; and though he thought him a very bad subject for the operation, yet he did not care to deny his most earnest request, seeing no other possible means left of affording relief in his miserable condition. Considering the rigidity of the fibres in an old person, and that their natural contractile power, evident in the division of an artery, must be greatly weakened in this case, Mr. G. was afraid, that the agaric, if it should answer, would not act so expeditiously as it did in the other, and that probably they might meet with much more difficulty in restraining the haemorrhage. Therefore, to assist it all he could, he tacked it to thick compresses of lint with pieces of card in the middle, thinking by that means he could apply it more readily, and keep it in stronger and closer contact with the mouths of the vessels, if he should find it necessary; for he was very solicitous for the support of its credit and reputation, his own being connected in some measure with it, and the patient's welfare also depending on it. He applied most of the pieces without being under a necessity of having the tourniquet-ligature slackened, to show the mouths of the vessels; then covered the stump thick with lint, applied a pledget of tow spread with common digestive over it, and over that a circular piece of stiff paper, to make the pressure of the palm of the hand more equal. This done, after 3 or 4 mi- nutes he desired his assistant to slacken the tourniquet-ligature; on which it bled at a great rate, and made some of his brethren soon imagine, and declare, they thought it would not do in this case. Mr. G. was not without the same fears; but went on with resolution, and every thing was conducted without hurry or confusion. He desired to have the tourniquet-ligature let quite loose, in order to remove, as much as possible, all impediment to the reflux of the blood, 4 a2 548 PHILOSOPHICAL TilANSACTlONS. [aNNO 1754. and made a strong compression at the end of the stump, on which the bleeding ahnost intantly abated, which was totally stopped in about half an hour after; and, in the whole, he believed he did not lose more than 12 oz. of blood. Now, apprehending that the circular structure of the common bandage, as usually applied, might produce the same inconvenience, which he observed arose from the tourniquet-ligature before it was quite loose, if no other attended it, having strong suspicions of tight bandage doing much mischief, he therefore only put several strips of common plaster, about an inch broad, over the piece cf stiff paper at the end of the stump, to meet and lap over at the top of the knee when bent, and then slipped on a barber's woollen cap; which method seemed to answer the purpose very well in this, as he had found it do in some other amputations. A physician, and 4 surgeons of eminence, who were desirous of seeing the effect of the agaric, were present at the operation. Four days after he opened the stump, but took, away no more of the dressings than what were loosej among which were '2 or 3 pieces of the agaric, without any signs of fresh bleeding, or visible pulsation at the ends of the arteries. Two days after he dressed it again; the stump then appeared well digested all over, and had a much better aspect than could reasonably be expected in such an unpromising subject; and appearances were so favourable as to give hopes -of his recovery, though he was not without distant fears, which he was guarding against as much as possible. C Extract of a Letter from Mons. Bonnet, F. R. S. of Geneva, to John Cle- phane, M. D., F. R. S. Translated from the French. Dated Geneva, June 3, 1754. p.818. The inoculation of the small-pox continues to be attended with the greatest success in our city. Of 70, who were inoculated, there was not one in any danger. Lausanne has been as it were forced to imitate us; and we hope, that this excellent method, which we received from England, will spread itself from one place to another, for the good of mankind. Mons. de la Condamine has read to the Royal Academy of Sciences at Paris a dissertation on this subject, which was greatly applauded. But I presume, that the French will be a long time in adopting the practice of inoculation. The clergy there throw a terrible obstacle in its way. CI. Extract of a Letter from Constantinople, of the iQth September, 1754, from Murd. Mackenzie, M. D. concerning the late Earthquake there, p. 81 9. On the 2d instant we had a terrible shock of an earthquake, about ^ after 9 at night, which moved from east to west, and has done a great deal of mischief here, and in the neighbourhood. I shall only mention what I have seen. Four of the 7 towers are much hurt ; one of them, which is an octagon, has VOL. XLViri.J PHILOSOPHICAL TRANSACTIONS. S40 2 of its sides thrown down from top to bottom. It is said several of the Jani- saries, who were on guard there, are killed. The 3 other of the 4 are much shattered, and part of the walls fallen down. All the turrets, on the city wall, from the 7 towers to the Adrianople-gate, are much shattered, though none fallen ; all the cupolas of the portico of Sultan Mahomet the lid's mosque are thrown down ; the Sickergee Han, a strong stone building near the above mosque, is quite destroyed: some part of the wall of the Cara Han is thrown down; one bagnio is quite fallen, and many people said to be destroyed in it. The Cautir- ligee Han is quite down; and the Vizir Han much shattered; 7 minarets (co- lumns from whence the people are called to prayers) of small mosques are thrown down; the mosque called Little Santa Sophia is much damaged, and the prison of Galata is quite down, and all the prisoners buried in its ruins. There has been much damage done at Balat, a large suburb, Scutari, and on the canal; and there are bad accounts from Nicomedia, but none well avouched. There have been several small shocks felt since, but none have done any harm. Some say there were 2000 people destroyed by this calamity, in the town and suburbs; some QOO ; and others reduce them to about 6o, who, by what I have seen, are nearer the truth. The shock at Smyrna, in the year 1739, which I also felt, was much stronger. On the 6th, about 9 at night, there appeared a cloud due west, when it began to lighten and thunder, and the thunder continued, without any interval, till half an hour past 10, moving gradually to north-east, where it ceased, and the night was very serene and calm after it. About 10, when the thunder was north of us, it rained for a quarter of an hour very heavily, then became clear, and all the stars appeared. Such a peal of thunder I never heard in any country; for I can aver, that it did not stop a minute in an hour and a halfs time. Another letter, dated Oct. 1, says, that a Tartar was arrived express from Armenia, in 10 days, with advice, that the city of Sivas, one of the Sebastias of the ancients, was quite destroyed by an earthquake, on the same night, ih which that was felt at Constantinople; and that a lake of fresh water is risen where the town sunk. The earthquake was felt at Angora and Smyrna, but there was no notice that they had felt any thing of it at Aleppo, though there were letters from it about that time. CII. Extract of a Letter from Camillo Paderni, Keeper of the Herculaneum Museum, to Thomas Hollis, Esq. relating to the late Discoveries at Hercula- neum. Dated Naples, Oct. 18, 1754. p. 821. The first thing here discovered was a garden, in which were found several marble statues of excellent Greek artists. This route led towards a palace, which lay near the garden. But before arriving at the palace, they came to a 550 PHILOSOPHICA.L TKANSACTIONS. | ANNO 1754. long sqnare, which formed a kind of forum, and was adorned throughout with columns of stucco; in the middle of which was a bath. At the several ano-les of the square was a terminus of marble, and on every one of those stood a bust of bronze, of Greek workmanship, one of which had on it the name of the artist, AnOAAfiNlOI APXIOT AeHNAICI. A small fountain was placed before each terminus, which was constructed in the following manner: level with the pavement was a vase to receive the water, which fell from above; in the middle of this vase was a stand of balustrade work, to support another marble vase. This 2d vase was square on the outside, and circular within, where it had the appearance of a scallop-shell ; in its centre was the spout, which threw up the water, that was supplied by leaden pipes inclosed within the balustrades. Among the columns, which adorned the bath, were alternately placed a statue of bronze, and a bust of the same metal, at the equal distance of a certain number of palms. Seven statues were taken out from April 15 to September 30, near the height of 6 Neapolitan palms, except one of them, which is much larger, and of an ex- cellent expression. This represents a fawn lying down, which appears to be drunk, resting on the goat-skin, in which they anciently put wine. Two other of these statues are of young men, and 3 of nymphs, all of middling work- manship. September 27, I went myself to take out a head in bronze, which proved to be that of Seneca, and the finest that has hitherto appeared, being as excellent a performance as can well be conceived. Our greatest hopes are from the palace itself, which is of a very large extent. As yet we have only entered into one room, the floor of which is formed of mosaic work, not inelegant. It appears to have been a library, adorned with presses, inlaid with different sorts of wood, disposed in rows; at the top of which were cornices, as in our own times. I was buried in this spot more than 12 days, to carry off the volumes found there; many of which were so perished, that it was impossible to remove them. Those, which I took away, amounted to the number of 337, all of them at present incapable of being opened. These are all written in Greek characters. While I was busy in this work, I observed a large bundle, which from the size, I imagined must contain more than a single volume. I tried with the utmost care to get it out, but could not, from the damp and weight of it. However I perceived, that it consisted of about 1 8 volumes, each of which was in length a palm and 3 Neapolitan inches ; being the longest hitherto discovered. They were wrapped about with the bark of a tree, and covered at each end with a piece of wood. All these were written in Latin, as appears by a few words, which broke ofF from them. I was in hopes to have got something out of them, but they are in a worse condition than the Greek. From the latter the public will see some entire columns, having myself had the good fortune to extract 2, and many other fine fragments. Of all these an account is drawing up, which VOL. XLVIII.J PHILOSOPHICAL TRANSACTIONS. 551 will be published together with the other Greek characters, now engraving on copper-plates, and afterwards make a separate work by themselves. At present the monk, who was sent for from Rome, to try to open the former manuscripts, has begun to give us some hopes in respect to one of them. Those which I have opened, are philosophical tracts, the subject of which are known to me; but I am not at liberty to be more explicit. Cllf. Extract of a Letter from Sir James Gray, Bart, his Majesty's Envoy to the King of Naples, relating to the same Discoveries at Herculaneum. Dated- Naples, Oct. 29, 175-1. p. 825. Several curious and valuable things are daily found in the mine of antiquities at Portici. They have lately met with more rolls of papyri of different lengths and sizes, some with the umbilicus remaining in them ; the greater part are, Greek in small capitals. The Canonico Mazocchi, who is much esteemed for his learning and knowledge of antiquity, is employed in copying and explaining 5 entire columns, that have been lately unrolled off^ one of the papyri, which gives some hopes of further discoveries. This manuscript treats of music and poetry. The Epicurean philosophy is the subject of another fragment, a small bust of Epicurus, with his name in Greek characters, was found in the same room, and was possibly the ornament of that part of the library, where the writings in favour of his principles were kept; and it may also be supposed, that some other heads of philosophers, found in the same room, were placed with the same taste and propriety. Last week were found 1 fine bronze heads, of excellent workmanship, one of Seneca, and another of a captive king. The king spares no expence in reco- vering and preserving these valuable remains. In order to satisfy the curiosity of the public, he has ordered a catalogue to be printed, with some designs of the principal statues and paintings, which will be published soon. A more exact ac- count of these discoveries will some time or other be given by Monsignor Baiardi, who, in 3 large 4to volumes already printed, has not finished his introduction. CIF. Of some Trials to keep IVater and Fish stveet, tvith Lime-water. By Stephen Hales, D. D., F. R. S. p. 826. Dr. Alston, of Edinburgh, had found, that the small proportion of a pound of slacked lime to a hogshead of water, stirring it, effectually preserved the water sweet, not only in a glass or earthen vessels, but also in a new oaken vessel. April 9, Dr. Hales put into a 7 gallon cask of water, in the proportion of a pound to a hogshead, some white marble lime; which was what they call sweated, that is wrapped in dung, without which sweating, it is said, that it will not be reduced to lime. — April 26. It had some taste of the wood, and a small degree 552 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. of ill smell, which being something more so on July 27, it was then poured away. July 15, He put into an 18 gallon cask 18 ounces of unslacked stone-lime, made of very hard stone of the Clee-hills in Shropshire; that is, in the propor- tion of 44- lb. of lime to a hogshead of 72 gallons. — June 25, the water was sweet, but had a disagreeable taste of the cask, and continued the same Aug. 24; but Oct. 17 the taste was something worse. And, Nov. 12, there seemed to be a very small degree of a putrid smell and taste. But the prevailing; dis- agreeable taste was from the wood of the cask, which discoloured the water in some degree. He put also into a 9 gallon cask 1 ounces of the same unslacked stone-lime to a gallon ; which was in the proportion of 9 pounds to the hogshead, and found it much the same all along as the former. With chalk-lime, in the proportion of 2 lb. to a hogshead, it soon stunk much, and continued so to do for 4 months. This was Thames water, taken up below London-bridge, which is well known to grow sweet again, after having stunk for some time. So that chalk-lime (almost the only sort in use here), will not preserve water from putrefaction; though stone-lime, as Dr. Alston has happily discovered, does preserve water in a great measure from the great de- grees of putrefaction it is subject to, and therefore may be very serviceable at sea. Being informed, by one who had been in the East Indies, that native mineral sulphur had been found to keep water sweet there in earthen jars, at land, and also at sea. April 2, he put into a kilderkin, or 18 gallons of pure pond water, a pound of native mineral sulphur, in 7 lumps. April 26, sweet. May 3, be- gan manifestly to stink. May J, stunk much, and was poured away. May 8, the kilderkin being scalded, and made sweet, it was filled again with the same pond water, and 6 lb. of native mineral sulphur put into it. July 27, it was sweet. Oct. \7 , '\t was discoloured, and somewhat in a small degree fetid. Nov. 12, the same. Hence native mineral sulphur may be of service to preserve water from great degrees of putrefaction at sea. Dr. Alston having written that he found fish would continue sweet in lime- water for 7 weeks and more. April ig, Dr. H. put 4 gudgeons into white marble lime-water. May 10, they were sweet; but on boiling one of them, the flesh, though sweet, was reduced to be soft pap. And Mons. Clairaut, who was at Lapland, to measure a degree of the earth, told Dr. H. on this occasion, that the fish, which they there kept long dried, were thus pappy when boiled, but not unwholsome. May 22, they smelled sweet, and were firm to the feeling; but on boiling one of them, it dissolved away like anchovy. June 12, another of the gudgeons, though sweet and firm VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 553 to the touch, being put into new-made stone hme-water, which was only milk- warm, dissolved also, and the bones of the head were rotten and brittle. June 18, two small eels, skinned, were put into stone lime-water. June 22, one of them, which was firm to handle, when boiled was soft and pappy. June 25, the other eel was the same when boiled. In order to try whether the lime, which adhered to, or had soaked into, the flesh of the fish, which had lain in lime-water, had the quality of thus dissolving the texture of the flesh in boiling, Dr. H. boiled a small eel, and a morsel of mutton, for 10 minutes, in stone lime-water, when they were boiled enough, and were of a due degree of firmness, and not pappy. A like eel, boiled in well- water, was boiled enough in 5 mirmtes. Hence it appears, that the lime does not, in boiling so short a time, dissolve the texture of the flesh into a pap, which must therefore be the effect of unfetid putrefaction. But lime-water made of chalk lime has very little of an antiseptic quality. For last year, in the month of May, he put some gudgeons, and an eel, into our common lime-water, and in 7 days boiled one of the gudgeons, but found it too putrid to eat. After 28 days he boiled another, and it dissolved almost into insensible parts; which shows, that it was much putrefied. Dr. Alston likewise informed him, that he put a piece of veal in pounded or slacked stone-lime, which in a week became tough and dry. Dr. H. put a piece of veal, from half to three-quarters of an inch thick, into chalk-lime, on May the 10th, and on the 31st of the same month it had a putrid smell, and was in the middle red and raw, with a thin hard outside. Having communicated these experiments to Dr. Pringle (whose trials having been made with chalk lime-water, which is in common use here, agreed with the last of mine), he observed, that the difference between stone lime-water and chalk lime-water, might probably consist in this : the chalk, before calcination, being a highly septic substance,* if some of its particles were not fully calcined, these, by mixing with the water, would impart to it some degree of a putre- fying quality, contrary to that virtue the water receives from such parts as are sufliciently burnt. That the same would be the case of shells, also septics; and therefore that the lime-water, made either of chalk or shells, would prove more or less antiseptic, or even continue septic, according to the degree of calcination. He added, that as all his experiments, relating to the antiseptic quality of lime- water, were made in a furnace heated to the degree of human blood, a circum- stance which he had marked in his Observations,-f- the uncalcined parts of the • Observ. on »he Diseases of the Army, 1st ed. p. 390. — Orig. t To one of the experiments preceding that on the lime-water, the author subjoins the following note: " All the following experiments, whether made in the lamp furnace, or by the fire, were in a degree of heat equal to that of the human blood, viz. 100° of Fahrenheit's scale." p. 383.— Orig. VOL. X. 4 B 654 I-HILOSOPHICAL TRANSACTIONS. [aNNO 1754. lime would in that state become more active in promoting putrefaction, than when the trials were made in cold water. And indeed it must be owned, that when any experiments are made on medi- cinal substances out of the body, the nearer we can make them to the heat of the blood, and to other circumstances those substances must undergo in the first passages, the more just the inferences will be, that are drawn from those ex- periments. In regard to that quality of lime-water, in preserving fish longer sweet than flesh. Dr. Pringle took notice, that he doubted it was a common mistake to ac- count fish a more corruptible substance than the flesh of land animals. For though fish might become sooner stale for eating than most flesh meats, yet that fish did not so soon rise to a rank degree of putrefaction as flesh; and there- fore that the former would be kept longer tolerably sweet than the latter by any kind of antiseptic. CV. Medical and Chemical Observations on Antimony. By John Huxham, M. D., F. R. S. p. 832. In the present advanced state of pharmaceutical chemistry, it is deemed unne- cessary to reprint this long paper on the different preparations of antimony. Dr. H. particularly recommends his so called essence of antimony, or vinum anti- moniale, prepared by infusing either the glass of antimony or regulus of anti- mony in white wine. This he preferred to every other antimonial medicine. CFl. Of Mr. Samuel TiilVs Method of Castrating Fish. Communicated by W. Watson, F.R.S. p. 870. Several years since, Mr. TuU of Edmonton performed the operation of cas- trating fishes, before Sir Hans Sloane, Bart, and several members of the Royal Society, who met at Sir Hans house for that purpose. About 5 or 6 years ago he performed the same operation in presence of our late president Mr. Folkes, and others. In England, where in many parts sea-fish are in great plenty, the fish of rivers and ponds are less esteemed ; and improvements, either with regard to their bulk or increase, are less attended to; but in Germany, remote from the sea, where pond-fish are a great article of traffic, Mr. Tull's method may be of great use. Mr. Tull says that he castrates both the male and female fish; and that, although almost any time is proper for the operation, the least so is just after they have spawned, as the fish then are too weak and languid to bear, with success, so severe an operation. The most eligible time however is when the ovaries of the female have their ova in them, and when the vessels of the male, analogous VOL. XLVZII.3 PHILOSOPHICAL TRANSACTIONS. 565 to these, have their seminal matter in them ; inasmuch as at this time these vessels are more easily distinguished from the ureters, which convey the urine from the kidneys into the bladder, and are situated near the seminal vessels on each side of the spine. These may, without sufficient attention, be taken for the ovaries ; and the more so, when these last are empty. When fishes have spawned a few weeks, they are fit for the operation ; for, like hens, they have small eggs in their ovaries as soon as they have laid their former clutch of eggs. When a fish is intended to be castrated, it must be held in a wet cloth, with its belly upwards ; then with a sharp pen-knife, with its point bent backwards, or other well-adapted instrument, the operator cuts through the integuments of the rim of the belly, and in doing this he carefully avoids wounding any of the intestines. As soon as a small aperture is made, he carefully inserts a hooked pen-knife, and with this he dilates this aperture from between the two fore-fins, almost to the anus. From the back of this instrument, being blunt, the danger of wounding the intestines is avoided. He then, with two small blunt silver hooks, of 5 or () inches long, by the help of an assistant, holds open the belly of the fish ; and, with a spoon or spatula, removes carefully the intestines from one side. When these are removed, you see the ureter, a small vessel, nearly in the direction of the spine ; and at the same time the ovary, a larger vessel, lying before it, that is, nearer the integuments of the belly. This last vessel you take up with a hook of the same kind with those before mentioned, and detaching it from the side far enough for the purpose, divide * it transversely with a pair of sharp scissars ; remembering always, that great care is taken in not wounding, or otherwise injuring, the intestines. After one of the ovaries has been divided, proceed in the like manner to divide the other ; and then sew up the divided in- teguments of the belly with silk, inserting the stitches at a very small distance one from the other. Mr. Tull first put this method into practice, in order to prevent the excessive increase of fish in some of his ponds, where the numbers did not permit any of them to grow to an advantageous size. But from castration the increase was not only prevented, but the castrated fish, as Mr. Tull asserts, grew much larger than their usual size, were more fat, and, which is no trifling consideration, were always in season. He observes further, that the spawning time is very various : that trouts, for instance, are full about Christmas , perch in February ; pikes in March ; and carp and tench in May. You must always, however, make some allowance for climate and situation, with regard to the spawning of fish. And, from a very * Mr. Tull has frequently, to prevent the re-union of the divided cvaries, by which the eflect of the oiieration might be defeated, taken out part of them, and yet the fish have survived. — Orig. 4 B 2 556 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754, diligent attention, he assures that he has been able to settle a point much contro- verted by naturalists, in regard to the copulation of fishes. The most generally received opinion has been, that they did not copulate ; but that the female did cast her spawn in the water, and that then it was fecundated by the spermatic matter of the male. Mr. Tull, in contradiction to this hypothesis, asserts, that he has frequently seen fishes in actual copulation ; and that this is generally done before the ova arrive at maturity. After Mr. Tull has castrated his fish, they are put into the water where they are intended to continue. He makes no particular appropriation, neither with regard to the ponds into which they are put, nor does he give them any particu- lar nourishment ; but they take their chance in common with other fish, as though they were not castrated. And he remarks further, that if tolerable care is taken, very few fish die of the operation, when performed in the manner here described; though heretofore, when, instead of the belly, he made the opening in the sides of the fish, numbers died, from his wounding the intestines, and frequently dividing the ureters. evil. An Attempt to point out, in a concise Manner, the Advantages which will accrue from a Periodic Review of the Variation of the Magnetic Needle, throughout the knoivn IVorld; addressed to the Royal Society, by Wm. Moun- taine and James Dodson, Fellows, and requesting their Contribution thereto, by Communicating such Observations concerning it, as they have lately made, or can procure from their Correspondents in Foreign Parts, p. 875. About the year I700, Dr. Halley having collected together many observations on the variation of the needle, in several parts of the world, drew (on a mercator chart) certain lines, showing the quantity of that variation, in those parts of the world, over the representation of which those lines were drawn ; but as the quan- tity of this variation is in a perpetual state of fluctuation, in perhaps every part of the world, it had been so much changed in the space of about 40 years, that when the writers of this paper endeavoured, about the year 1744, to draw on it other lines to answer the purposes above mentioned, they found that those laid down by Dr. Halley were grown entirely useless ; and that a system of such lines, or something analogous, should be performed once in every 10 or lj2 years at least, m order to answer the purposes intended by that gentleman. In the reconstruction of them, the writers received the assistance of the com- missioners of the navy, and of the directors of the East-India and African com- panies, having leave to peruse the journals of those mariners which were under the direction of each respective body ; from these, and a few private communica- tions, they were enabled to draw the proper lines over the most frequented seas. and to make some attempts toward doing the same in those least so ; a copy 01 VOL. XLVIII.] PHILOSOPHICAL TRANSACTIONS. 557 the chart, thus again rendered useful, they presented to the r. s. with an account of the methods used in performing the same. Though the most beneficial use of these lines belongs to the sea, yet if they could be extended over the land likewise, the advantages arising would more than compensate the trouble, as will appear by taking a short view of each. And first, the use of these lines at sea may be considered either as common to the art of navigating in all large bodies of water; or as particular in some such : the general use being that of steering the true course designed, and finding the ship's true place, as near as may be, by what the mariners call the dead reckoning. The particular uses will be best explained by examples : for instance, in the southern parts of the great Atlantic ocean, beginning with the coast of Brazil and Patagonia, and proceeding to the south of the Cape of Good Hope into the Indian ocean, as far as the common tracks of our East-India ships extend, the variation lines have appeared to be, for the most part, directed northward and southward : whence, in most places of that great body of waters, if the lati- tude and variation be found by celestial obsei-vations, the longitude will be ob- tained by the lines on the chart ; the great usefulness of which has been attested to the writers, by many persons who have, successfully to themselves, practically applied the last constructed chart, to correct their dead-reckoning on that long passage. Indeed, where the variation lines run nearly eastward and westward, as has appeared in the Atlantic ocean, from the west coast of Europe to the east coast of North America, no assistance toward obtaining the longitude can be derived from them ; but as it frequently happens, within those limits, that meridian ob- servations, for determining the latitude, cannot be obtained, especially about Newfoundland ; then, if a good observation of the variation can be taken, at any time of the day, the latitude may be nearly ascertained by the lines on the chart. Secondly, the advantages that will arise by extending the variation lines over the land, as well as sea, will be the confirmation of those drawn over the waters ; the continuation of which, from sea to sea, will be thus conspicuous, and we hall be enabled to judge better of their nature, properties and causes; and if the same can be extended over all the parts of the known world, the eye will be presented, at one view, with the different degrees of attraction, with which all the parts of this great magnet are endued, at the time when such lines are drawn ; this the writers would have attempted to do, in the year 1 744, if they could have procured a sufl^cient number of observations for that purpose ; but though they frequently advertised their request, in the public papers, no assist- ance was obtained. As the writers have by experience found, that the proper period for re-examin- 558 PHILOSOPHICAL TRANSACTIONS. [anNO 1755. ing the state of the variation, is now at hand, without which the above-men- tioned valuable advantages of the chart will be lost to the mariner ; they have determined to collect and compare all the observations that can be procured by them, in the space of a year from this time, or so long after as the return of the East-India ships then next following ; if such delay should become necessary, by the arising of any doubt in consequence of such comparison ; and then to publish the result of their process, in such a manner as shall seem most convenient. Several of the learned and ingenious have endeavoured to account for this phenomenon of the variation of the magnetic needle, and its continual mutation ; whence different methods of computation have been proposed, by which they have endeavoured to determine what the quantity of the variation, according tq their several hypotheses, will be at any given place and time: the above propo- sition therefore will, if carried into execution, bring these severally to the test, and enable the judicious either to approve or reject them ; the writers being de- termined to publish nothing which shall not be warranted by the real observa- tions, which shall come into their hands, and shall leave the application to others: if any of them should be so far confirmed, by this examination and comparison, as to give just ground for a calculation, their labour will be at an end ; but if not, they humbly recommend the continuance of such a periodic operation, as they now propose to undertake, being the only means of attaining such a desirable event, and of supplying the defect till it can be obtained. END OF THE PORTY-EIGHTH VOLUME OF THE ORIGINAL. Art. I. On the Pressure of Weights on Moving Machines. By Christian Hee, Professor of Mathematics and Experimental Philosophy in the Marine Insti- tution of Copenhagen. From the Latin. Vol. XLIX. p. \. Let fig. 9, pi. 11, represent an axe-in-peritrochio. Let a be the moving power ; its distance fi-om the centre of motion a ; also b the weight, h its distance from the centre ; and c the radius of the axis where the friction is. Further, let m denote the weight of the machine, and d the distance of the centre of the forces from the centre of gravity. It is required to find the pressure on the axis, when the descending power a actuates the machine. If now the pressure arising from the descending power a, or that by which the thread is stretched at the side a, be called %; then, by the equality of action and re-action, the pressure or tension at the other side j3 will be = -7 ; hence the whole pressure, exclusive of the weight of the machine and cord, will be = tt + VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 55Q -r = (^ "'" i") '^' ^* "^^^ ^^^ constant ratio of the pressure to the friction be that of 1 to /* ; then the friction will be ( 1 + -) ttjw, ; and the momentum of this friction = (1 + r) CTTj/. : but the momentum of the friction from the weight of the machine is = mc;u ; which added to the former momentum, gives ((1 + ^) » + m) Cf* : hence the momentum of the moving power is=Aa — sb — ((j + i) TT + m) c/x. But since the momentum of inertia is aoj'* + si* + mcP; Aa— Kb— ((1 -(- -) T + M) Cfo therefore the accelerating force will be = — — j-—, — tt ; and for the acceleration of the point a, or of the moving power a, it will be, by the Aa* — sab — ((1 + ^) »' + m) «Cj* principles of mechanics, T^-TlW+Md^ X / = c; where/ denotes the element of the time, and c the element of the velocity. But if a should fall freely, it would be - / = /. And since the increments or decrements of velo- cities, generated in the same particles of time in the same body, are as the ge- nerating forces, therefore >' : / — <■:: a : the force generating the decrement of celerity '/ — c, which is the same force that retards the fall of the body, stretches the string, and presses on the side « ; hence, substituting for the values, we Afl' — Ba6 — ((1 + ^) » + m) ac/b have the following analogy 1:1 ^^ + bA' + mI^ :: a : tt ; there- ab6* + AMd* + ABOA + ((1 +^)'f + m) Aac/* fore IT = gi 4, b6» + Mrf* ' ^^°^ which equation is found abA^ + AM(f* + ABaA + A Mac/* 1 Afl* + bA» 4- Mrf» — (1 + T)*OCIb wa ABaA +AMO' J- + ABO* + AM -j- — , and the whole pressure * Aa» + bA" + mcP - (1 + f-) AOC(i* AB (a + A)' + am («P + ac/i.) • ( 1 + f ) -l'" — * Aa« + bA« + Md* - (1 + A ) Aflc,* If now we should exclude the friction and the weight of the machine, we should have the whole pressure = ^^^^- And if, as is the case in the .,, , AB (a + A)* 4ab pulley, we suppose a= b, the whole pressure will be = -^^-qrjj-^ = j:^^' 500 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. //, Investigation of a General Rule for the Resolution of Isoperimetrical Pro- blems of all Orders. By Mr. Thomas Simpson, F.R.S. p. 4. The different species of problems comprehended under the name of Isoperi- metrical ones, are of much greater extent than the name imports; since, not only the determination of the greatest areas and solids, under equal perimeters or bounds, whence the name is derived, but whatever relates to the maxima and minima of quantities depending on a line, space, or body, of which the figure is unknown, is by mathematicians included under that denomination. But not- withstanding the usefulness and great extent of this subject, nothing had been done in it further than the resolution of certain particular cases (such as finding the line of the swiftest descent, and the solid of the least resistance), till the ce- lebrated mathematician Mac Laurin, in his treatise effluxions, gave the investi- gation of an elegant and very easy method, by which the principal problems belonging to the first order may be resolved. The paper Mr. S. now lays before the Society contains further improvements on this subject ; as it is by far more general than any thing yet offered, and is drawn up with a view to obviate the difficulties attending the resolution of a very intricate kind of problems, and thus to open an easy way to some very interest- ing inquiries in natural philosophy. But instead of reprinting the calculations, it will be better to refer to p. 98, &c. of the author's Miscellaneous Tracts in 4to, published 1757» where the same paper is given in a more extended and im- proved state. ///. On the Effects of Lightning at Plymouth. By John Huxham, M.D., F. R. S. p. 16. Sunday, December 15, 1754, 25 minutes after one p.m. a vast body of light- ning fell on the great hulk at Plymouth-dock, which serves to hoist in and fix the masts of the men of war. It burst out about a mile or two to the westward of the hulk, and rushed with incredible velocity towards it. The piece of the Derrick cut out was at least 1 8 inches diameter, and about 15 or 1 6 feet long : this particular piece was in 3 or 4 places begirt with iron hoops about 2 inches broad, and half an inch thick, which were completely cut in two by the light- ning, as if done by the nicest hand and instrument. The lightning was imme- diately succeeded by a dreadful peal of thunder, and that by the most violent snower of hail, which fell only in and about this town, for a mile or two : there was very little of it at the dock, though only 1 miles distant. The hail-stones were as large as small nutmegs, all very nearly of the same size and shape. They measured, immediately after they fell, near 2 inches round. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 3(jl ly. A Remarkable Case of a Morbid Eye. By Mr. Edward Spry, Surgeon, at Plymouth, in Devonshire, p. 18. The wife of Thos. Smaldridge, a mariner of Plymouth, complained to Mr. S. of a violent pain in her left eye, and sometimes of very acute pains in the temple of the same side, with some defect in her sight. She also imagined that her eye was larger than ordinary ; but on inspection it did not appear so. The cornea however became less transparent, and the pupil greatly dilated : but though the pain of her eye was so great, yet the blood-vessels of the conjunctiva were uo way enlarged, nor in the least redder than that and the sclerotica were before ; and, from its whiteness, it appeared no more morbid than the other. Having resorted to bleeding, blistering, mercurial purges, &c. without any good effect. Dr. Martyne of Plymouth was consulted, but with no better success, her pain increasing, rather than diminishing. And as the pupil became enlarged, and the cornea more opaque, with great inflammation of the conjunctiva and sclerotica, and an apparent prominence of the whole eye, when every thing hitherto failed, Mr. S. tried '2 or 3 drastic purges; but these disagreeing very much, he was forced to return to his former method. He then cut a seton in her neck, which run very much ; but all to no purpose, and she became still more miserable. The conjunctiva became greatly inflamed, with an eversion of the upper lid, attended with great pain. He often made incisions with his lancet on this coat, which bled plentifully, and gave her ease for a day or two, and even took 8 oz. of blood from the temporal artery. But the eye being greatly enlarged, and of so terrible an appearance, after all endeavours for 8 or 10 months, he judged her disease to be a carcinoma, and therefore proposed cutting out the whole eye as the only remedy. Several skilful surgeons were consulted, and it was agreed to defer the opera- tion, and trust to nature ; though she was in that miserable condition ; but at length her eye becoming much greater, and her pain being increased, he re solved on the operation, lest the bones of the orbit might become carious. Thus, having called in Dr. Huxham, with some of the most skilful surgeons of Plymouth, he performed the operation in the following manner ; viz. the tu- mor was so very large, and the upper lid so distended, that he was obliged first to divide the orbicular muscle at the inner canthus ; and there began the incision round the upper part of the tumor, for the more convenient use of the knife. He had not cut deep when a great quantity of pus, like lymph, flowed out with great force, like a fountain, and the tumor subsided a good deal; but pursuing the operation, he found a large cist, which filled the whole orbit behind the eye ; and so part of the cist was left to slough oft' with the dressings. The whole eye VOL. X. 4 C 562 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. being cut out, he filled the wound with lint, 8cc. and in 3 days removed the dressings, with a great quantity of sanies, which were daily renewed, and tlie part of the cist, which was left behind, sloughed off the id day. The cure went on with success, and, in a month from the operation, was completed ; and she remained free from pain from that time to the above date. Having examined the diseased eye after its excision, they found the humours very much confused : the aqueous humour was not so clear as usual, the crystal- line less solid and transparent, and the vitreous almost reduced to a liquid state. The cist was very strong and elastic, and had a cavity large enough to contain a hen's egg. V. A Supplement to the Account of a Distempered Skin, published in the A2Aih iV" of the Phil. Trans.* Bjj Mr. Henry Baker, F.R.S. p, 21. In 1731, a lad, 14 years of age, was brought by his father from Euston-Hall, in Suffolk, and shown to the r.s. on account of his having a cuticular disorder, of a different kind from any noticed in the histories of diseases, as mentioned in the aforesaid N° of the Phil. Trans. More than 24 years from the date of that account, he was living, and shown at London by the name of the porcupine-man. His name was Edward Lambert. He was then 40 years of age, a good-looking, well-shaped man, of a florid coun- tenance ; and when his body and hands were covered, seemed nothing different from other people. But except his head and face, the palms of his hands, and bottoms of his feet, his skin was all over covered in the same manner as in 1731. This covering seemed to Mr. B. most nearly to resemble an innumerable com- pany of warts, of a dark-brown colour, and a cylindric figure, rising to a like height, and growing as close as possible to each other ; but so stiff and elastic, then when the hand was drawn over them, they made a rustling noise. When he saw this man, in September 1755, they were shedding off in several places, and young ones, of a paler brown, succeeding in their stead, which, he said, happened annually in some bf the autumn or winter months : and then he commonly was let blood, to prevent some little sickness, which he else was sub- ject to while they were falling off. At other times he was incommoded by them no otherwise, than by the fretting out his linen, which, he said, they did very quickly : and when they came to their full growth, being then in many places near an inch in height, the pressure of his clothes was troublesome. He had had the small-pox, and been twice salivated, in hopes of getting rid of this disagreeable covering : during which disorders the warting came off, and his •Vol. vii, p. SW, of these Abridgments. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 563 skin appeared white and smooth, like that of other people ; but on his recovery, it soon became as it was before. His health at other times had been very good during his whole life. But the most extraordinary circumstance of this man's story was, that he had had 6 children, all with the same rugged covering as himself: the first appearance in them, as well as in him, came on in about g weeks after the birth. Only one of them was then living, a very pretty boy, 8 years of age, whom Mr. B. saw, and examined, with his father, and who was exactly in the same condition, which he thought needless to repeat. He also had had the small-pox, and during that time was free from this disorder. f^I. Chi the lale Eruption of Mount Fesnvius. By Isaac Jamineau, Esq. his Majesty's Consul at Naples, p. 24. In April 1754, the fire issued from one end of a hillock, in the shape of a crescent, within the crater. On his 2d visit, in September, the crescent was turned to a cone, but much higher than before, being increased in proportion to the fire, that now discharged, by frequent explosions, thousands of stones on fire. On a 3d visit, in the middle of October, the cone seemed lower, which was owing to the rising of the bottom of the cup, whose depth from 80 feet was decreased to 50. The lava was actually running in many places ; and where it was not, the fire was universally visible within a foot or two of the surface. The running of the lava within the crater increased daily, so that in a month's time the cup was filled within 25 feet. On Tuesday, December 3, at night, after a little shaking, which was not felt above 2 or 3 miles ofl^", an opening burst on the eastern side of the mountain. Notwithstanding its slowness, it drives the strongest stone fences before it, and from lighting the trees, like torches, affords a most extraordinary, though dismal and pitiful spectacle. But the lesser stream which I saw before, is a small trout-stream compared to this, which sets off in a cascade of a mile's length, and, though rather with a less declivity, is equally rapid, from the greater quantity of matter rushing down it. The breadth about 60 feet at the top ; but by having melted down an island, that divided its stream about 200 yards in the fall, the breadth in that place must be above 1 00 yards. FII. An Account of the Species of Plant, from ivhich the Agaric, used as a Styptic, is prepared. Bij Mr. JVm. JVatson, F. R. S. p. 28. Mr. W. having written to M. Clairaut of Paris, requesting him to put some questions to Messrs. de Jussieu and Morand, concerning the species of agaric used as a styptic, he received for answer that it is the 4c 2 564 PHILOSOPHICAL TRANSACTIONS. [aNNO J 755. " Agaricus pedis equini figurd. Inst. Rei Herbar. " Fungus in caudicibus nascens, pedis equini figurS. C. B. Pin. " Fungus durus arborum, sive igniarius. Park. Theat. " Fungi arborei ad ellychnia. I. B. " Fungi igniarii, Caesalpini et Tragi. " Boletus acaulis pulvinatus laevis, poris tenuissimis. Linn. Flor, Suec. It is the agaric employed for the amadoue ; and Mr. Brossart, who first brought this preparation into practice, conceives that that which grows on old oaks, which have been lopped, is the most valuable ; that it should be gathered in August or September, and be kept in a dry room. The way of preparing it, is to take off with a knife the white and hard part, till you find a substance so soft, as to yield under the finger, like shammoy leather. This is to be divided into pieces of different sizes and thickness : beat these with a hammer, to give them a still greater degree of softness, so that they may be easily torn with the finger. Mr. Morand thinks, that the agaric, which when growing is of a greyish colour on the outside, is better than that which is white.* VJII. Of a Mountain of Iron Ore, at Taberg in Sweden. By Peter ^scanius, M. D. Translated from the Latin by Mr. Emanuel Mendes de Costa, F.R.S. p. 30. The mines of Sweden are justly esteemed superior to the mines of most other countries; and those of iron are the most famed. Among the most curious of the latter, is that of Taberg, if, with propriety, it can be called a mine. The Swedish iron is, and has always been, carried to most parts of Europe, and is preferred to all other iron. This mountain is situated in a sandy tract of land, of which the sand is ex- tremely fine. The whole mountain is one mass of rich iron ore, and even in some parts is mixed with particles of native iron. About 200 years ago (for so long have they worked on this mountain) they blew up the masses of ore ; yet the mountain appears very little diminished, except in the laves or hollow places, which are at the foot of the mountain, opposite to the valley. In the interior fissures of the mountain, bones of animals, as of stags and other kinds, are fre- quently found imbedded in the sand. No ore is found beyond the foot of the mountain, nor on the neighbouring plain ; so that it appears, as if the mountain Jbad been artificially laid on the sand, for it has no roots, or, like other moun- tains, its substance does not penetrate the ground. The ore breaks easily, and what is broken from the sides of the mountain readily falls to the foot of it ; while * The plant here mentioned is the boletus igniarius, Linn. VOL. XLIX.] PHILOSOPHICAL TKANSACTIONS. SSS in other mines the ore, with great trouble and cost, is dug from the bowels of the earth. The only inconveniency which happens here is, that the sand, which is digged in very great quantities in the fissures, when the ore is blown up, falls with it to the foot of the mountain, and buries or covers it, which they are forced to dig away again ; on which account they always blow up the ore from the bottom of the mountain upwards, for the greater ease of the miners, and to hinder the heaping of the sand at the bottom. They then carry the ore to the neighbouring furnaces, where being roasted, and broken small, they mix it with lime-stone and powdered coal, and smelt it into iron. IX. An Extraordinary Case of a Child. By Mr. Richard Guy, Surgeon, p. 34. A child near 7 years of age, having languished, for near 12 months past, of a supposed dropsy, and undergone the most skilful treatment of several eminent physicians unsuccessfully, died in an emaciated state. By desire of the parent, Mr. G. opened the body, expecting to find water, but to his great surprize, there appeared as follows : a large round solid substance, shaped in the form of an egg, weighing 14 lb. 24. oz. of the adipose cellular consistence; some parts of it being more brawny than others. On dividing it through the centre, were found several little cists, containing a meliceratous fluid ; the whole seemed en- veloped in a membrane, which he apprehended to be the omentum, but the ex- tension, from so large a body contained in it, had made it almost lose its reti- cular appearance. It was surrounded with many small blood-vessels, but no considerable ones. It adhered to the peritoneum, the back-bone, and almost all the internal cavity of the abdomen, resting the large end in the pelvis, and greatly compressing the bladder and ureters. The intestines were all crouded together on the right side, in as small a compass as could possibly contain them. The intestine colon passed round the lower part, in the form of an S, which adhered likewise : it also inveloped the right kidney, which appeared something larger than the other ; and on dividing it, he found small stones, not exceeding the size of a large pin's head. The other kidney did not adhere to this sub- stance. The small end pressed upwards against the diaphragm, so hard, as to force the heart close under the left clavicula : the lungs were so confined, as to render only one lobe capable of respiration ; the others appeared as in a still-born child. The liver, gall-bladder, and spleen, were as in health ; the intestines the same ; the mesentery was much extended with blood ; the matrix and ovaria as in their natural state ; and no other parts, that he could discover, affected. He could not discover, on dissection, any nuclei, that might particularly supply, or give rise to, this enormous substance. 566 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. X. Extracts of two Letters from Mr. James Latterman, Student in Physic and Surgery, to Dr. Schlosser, concerning the Effects of the Jgaric of the Oak, To which are added some rt-marhahle Experiments made on the Arteries of Horses, with the Powder of the Lycoperdon, or Lupi Crepitus. Bij M. La Fosse, Farrier to the King of France. Communicated by Mr. Joseph IVarner, F. R. S. Surgeon of Guys Hospital, p. 36. [In these letters some additional cases are given of the successful application of iigaric as a styptic after surgical operations. Also, of the application of the lycoperdon, with similar success. After the several cases of this kind, related in the preceding numbers of these Transactions, it is deemed suj^erfluous to reprint the detail of these additional experiments, especially as the surgical practitioners of the present day are agreed, that for stopping haemorrhages from the larger arteries, the ligature alone is to be relied on.J Respecting the manner in which these vegetable styptics act on the mouths of the bleeding vessels, Mr. La Fosse observes First, that when applied to the mouths of the divided arteries, the bleeding has ceased in a few minutes, and that the mouths of the divided arteries have healed up without any further dis- charge. Secondly, that in 24 hours after the application of this powder, a thin pellicle or skin is formed on the mouths of the divided arteries, and that within the vessels is found a small plug of congealed blood. Thirdly, that the pulsation of the artery is to be seen in a very distinct manner at the extremities of the vessels. Fourthly, that the coagulated blood is of a conical figure, whose basis is at the mouth of the vessel, and its apex in an opposite direction. XL On the Use of Lycoperdon, in Stopping Blood after Amputations.* By James Parsons, M. D., F. R. S. p. 38. XIL The State of the Thermometer, Feb. 8 and g, 1755. By Henry Miles, D. D., F. R. S. p. 43. The cold on the 8th, especially at midnight, was extraordinary, if it be con- sidered in how short a space of time it increased to that degree. The lowest state of the thermometer, was on the 8th day, at 7^ a. m. when it had fallen to in- XHL Some Cases of Dropsies, cured by Sweet Oil. By Wm. Oliver, M. D., F. R. S. p. 46. Mr. Pierce took from Miss 1 1 pints of water. As soon as the bandage could be loosened, Dr. Hartley and Dr. O. examined the state of her belly. The • Not reprinted for the reason assigned in the remark affixed to the preceding paper. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 56/ epigastric region was quite emptied; but they found a great fullness, which extended itself on each side the inguen, towards the back. They put her on a very spare dry diet, and gllowed her but a quarter of a pint of liquids in the 24 hours. But though her urine much exceeded in quantity what she drank, the swelling increased, and they feared the belly would soon fill again. A lady, who was with her, said that, just before she left London, she had heard that two persons had been cured of confirmed dropsies by being anointed, morning and evening, with common sallad oil, which was rubbed into the whole abdomen, for an hour at a time, with a warm hand. They could not refuse the trial of so innocent a method. The idtraleiptae began their operation. About the 3d day of anointing, the urine was considerably increased, and continued to be so. The fullness gradually decreased, and in a fortnight's time was quite gone. Her appetite, digestion, and sleep, grew natural, and she recovered flesh, strength, and spirits. About 6 weeks after her first anointing, her menses appeared, and at the end of the next month she had a regular return of good colour, and in sufficient quantity. Dr. O. saw her at the public room a week befoie, in as good health as she ever enjoyed. This recovery was much talked of, and set all the hydropics on rubbing. A man, aged 35, from hard drinking, and many wrong methods of cure, had been cachectic 1 5 years, and had often the symptoms of jaundice and dropsy. Half a year before, his belly, legs, and thighs, swelled to an enormous size. He was with difficulty moved from his bed to his chair, and was given over, as a person in an incurable dropsy. About 3 weeks before, he began to anoint. After 3 or 4 days rubbing, his urine was greatly increased; and in a fortnight, his belly, thighs, and legs, were wonderfully decreased; and Dr. O. saw him after- wards walking about the town, though before he could not move a joint. A woman 70 years of age, of a thin habit, who got a livelihood by carry- ing cakes about the town, fell into an ascites. Her belly was so greatly dis- tended, that she was obliged to quit her business, to confine herself to her house, and for the most part to her bed. She anointed. Her urine soon increased in quantity, and continued to do so. XIV. Observations of the Eclipses of Jupiter s Satellites at Lisbon. By John Chevalier, F. R. S. p. 48. Jan. 1 1, 1754, he observed the immersion of the 2d satellite at Q^ 4"' 3\ — Jan. 15, the 1st satellite immerged at 11*' 23™ 58'. — Jan. 18, the 2d satellite immerged at ll'' SS"" 30'. *£5" XV. Of those Malignant Fevers, that raged at Rouen, at the End of the Year 1753, and the Beginning of 1754. By Mons. Le Cat, M. D. p. 49. About the end of Nov. 1753, a malignant distemper broke out in Rouen; 568 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. the ravages of which continued during the subsequent months of Dec. Jan. and part of Feb. But before he enters on the history of this epidemic, he gives an account of the diseases which prevailed during some of the preceding years. The medical gentlemen, who had practised in Rouen from the beginning of the 18th century, state, that, for the last 30 years, that country had been more subject to malignant fevers than it had ever been before; and that the greatest part of them had been accompanied with miliary eruptions. M. le Cat fixes this epocha in 1723 and 1724, because the first of these years was excessively dry, the rain at Paris amounting to no more than 7 inches 8 lines, while the mean year comes to IQ, and the year 1724 had only 12; while the year 1725 pro- duced more than 17-J- inches, which should cause a temperature nearly approach- ing to the mean quantity, which may be considered as the most healthy. He observed in 1736 and 1737 certain gangrenous sore throats, which chiefly attacked children; they appeared again in 1748, in young persons of the first distinction, not only at Rouen, but also at St. Cyr, near Versailles, and at Paris. Persons of a certain age were also seized with it, not only in town, but in the country; and in some the tongue alone was the seat of the gangrenous eschar. In the same years 1737 and 1738, there was a great number of malignant perip- neumonies, of that kind called pituitous. The lungs of these subjects, many of which he opened, were become schirrous; and the patients perished for want of being able to admit air into them, as if they had been strangled. Some of them most earnestly begged him to open their breasts, imagining that a new vent would give them breath. In 1739 they had, at the Hotel Dieu, continual fevers, with frequent faintings: and the patients, without any violent symptom, died in 6 or 7 days. He found small abscesses in the substance of their hearts, near the auricles. Nothing remarkable happened from 1739 to 1743, but that the finest, longest, and driest summer he ever knew in Normandy, produced epidemical bloody-fluxes, which grievously afflicted both Rouen and the whole country round about. These fluxes were preceded by great lowness of spirits, attended with violent colics, and a sharp fever: the pulse small, the mouth and tongue foul, a nasty taste in the mouth, and frequent nausea; and whenever a hiccup came on, death was not far off. The principal seat of this distemper was in the large intestines ; though some- times the small guts and stomach had their share. In one, who voided pure blood a little before his death, he found a great portion of the intestinal canal full of blood, the villous coat being much swelled, and greatly inflamed; and, putting it in water, one might easily discern, with a magnifying glass, a great number of red points, which appeared to be the mouths of the vessels, which poured out the blood found in the intestines. Another had blood discharged VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. Sfig even up to the stomach ; and the inner membrane of this organ, towards the pylorus, was in the same condition with that of the great intestines of the fore- going patient. The duodenum, jejunum, and the beginning of the ileum, were sound; the end of the ileum was inflamed, and the large intestines were gangrened. In another, the same intestines were all mortified; the caecum, and half the colon, were as large as a stomach distended with wind. Their canals were full of a bloody matter, and their inner membrane separated very easily. The gangrene seemed particularly to affect this coat. The stomach and small guts were sound; yet his death was preceded by the hiccough. In some others, the gangrene had seized all the coats of the intestines; and sometimes these canals were so far pierced by the eschars, as to let the faeces pass through into the cavity of the belly. And in some the bladder itself partook of the dis- orders observed in the great intestines. A few bleedings at first, cooling liquors, as whey, chicken-water made into an emulsion, emollient clysters often repeated, and paregorics given properly, and in small quantities, were the most sovereign remedies for this disease. Pur- gatives were generally hurtful. Ipecacuanha succeeded with some; and an Eng- lish pupil, Mr. Greorge Ross, made very successful trials with boluses of vitrum antimonii ceratum. Whenever blood was taken away in an over great quantity, the patient in 3 or 4 days fell into the agonies of death. Anodyne drops given too fi-eely, instead of quieting, occasioned restlessness, and increased the fever and inflammation. M. le Cat was himself struck with this disease, as if with lightning, and passed, in a few hours, from a good state of health into a sinking and insensi- bility, which indicated a gangrene coming on, and the utmost danger. Two bleedings, close on each other, brought him to himself; but his insensibility was succeeded by the usual colic and flux, which was the principal distemper: then 14- oz. of diacodium freed him from this painful and dangerous condition, as speedily as the infected air had thrown it on him. In the following season, and even in the year 1744, when this distemper pre- vailed no longer epidemically, there happened some very extraordinary circum- stances. A woman, the 30th of November 1743, being of a robust habit of body, and in perfect health, was suddenly seized with a violent colic in her sto- mach, and died in 3 hours, He found 3 gangrenous places at the upper orifice of the stomach. He doubted whether ever any distemper could have deserved the name of a plague more than this, if it had been epidemical. In the course of the year 1 744, they had a great number of gouty rheumatisms, with fevers. The patients were deprived of the use of their limbs; the miliary eruption often came on, and seemed to relieve them by restoring their limbs. In some, their pains went off by forming phlegmons and erysipelases on the ex- VOL. X. 4 D 570 PHILOSOPHICAL TRANSACTIONS. [aNNO 1735. tremities; some of which seized the arm and fore-arm, and were considerable enough to bring on the death of the patients; others were attended with large gangrenous eschars, which also frequently proved fatal. Of all the remedies, that did service in these disorders, decoctions of the bark, and the sudorific woods, as also that of scorsonera, were most effectual. But if a plentiful mi- liary eruption came on, notwithstanding the relief it seemed at first to procure, the event seldom turned out well. The years 1745, 46, and 47, proved tolerably healthy; some disorders of the throat, becoming more common about the end of the last of these 3 years, were the fore-runners of the gangrenous sore throats of 1748. In these cruel dis- tempers, the throat was in the same state with that of the larger intestines in 1743. Great and frequent bleedings made the patients go off the sooner. There were also this year malignant fevers, that began with rigors, fixed pain in the head, pain about the heart, the fever in appearance very small, yet at- tended with delirium, and often with a miliary eruption. Those who died had the villous coat of the stomach spread over with inflammatory spots, which swelled its substance, and gave it a brownish purple-colour. These spots were in greatest number about the upper orifice of the stomach. The small guts had also some of these spots. Sometimes the glands of the mesentery were found obstructed, where the larger intestines, and other viscera, were in a sound state. He cured, or rather stopped the progress of, these distempers, by giving, on the first coming on of the rigors, a cordial and febrifuge electuary.* When the distemper did not yield to this remedy, he had recourse to small bleedings, and gentle physic. Such as were seized naturally with a slight flux, got well with the help of diluting liquors, made a little detersive, such as lemonade; but some of them lasted 40 days, and more. The years 1749, 50, and 51, had the like malignant fevers, some of which were accompanied with violent colics in the beginning, followed with fluxes, which it was found necessary to moderate. He succeeded with 1 or 2 blealings, after which he gave the decoctum album. -^ Some of these diseases had the appearance at first, of a slight peripneumony, or cold, with perpetual faint sweats: then followed a drowsiness and stupor, a rambling for some moments at night, the belly puffed up, and uneasy, little or no urine, then a miliary eruption and delirium ; and the patient was carried off in a few days. The stomach in these subjects was inflamed, as also the small guts, by patches. In some there were ulcers, which almost penetrated the sub- * Kinkina, 1 oz, ; Venice treacle and rhubarb, of each 4 oz. ; salt of centaury and wormwood, of each 1 dr. ; syr. of mercurialis, q. s. — Orig. + Crumb of bread, 2oz. ; hartshorn-shavings, * oz. ; root of the greater comfrey, cut in slices, 1 oz. ; to be boiled in a quart of water for a .J of an hourj strain, and add 1 oz. of diacodiura. —Orig. \ VOL. XLIX.] PHILOSOPHICAL TRAX'SACTIONS. 571' stance of the intestines. Their lungs were full of blood, and in the back part adhering to the pleura. Those, who had a slight looseness only in the morning, which did not check the sweats, recovered. Some of the malignant fevers, which were at the H6tel Dieu in J 750, were reported to be caused by infection conveyed in bales of horse-hair, to which was left some of the animals' flesh, that was become putrefied; and yet these fevers did not differ from others which we have already described. A girl about 20 years of age, who died of this fever, had the mesentery filled with obstructed glands, and the intestines mortified in different places. A man had, besides these symptoms, almost the whole mesentery mortified, and an an- thrax or carbuncle at the upper and fore-part of the arm-pit, and the whole body of a livid colour. This carbuncle proves, that these malignant fevers were some- thing pestilential. M. le Cat makes no mention of the small-pox, which hardly ever leaves this climate in any season of the year, but which is more common towards the end of summer, and in autumn, and for the most part is accompanied with the mi- liary eruptions, which he had already observed to be joined to all these diseases, and which seldom failed to render them mortal. He opened several of these variolous bodies, and in the greater nuniber found superficial ulcers on the ner- vous coat of the stomach, towards its upper orifice, with livid and inflammatory spots on the other parts of the same, as also on the intestines (though in a small number) and the glands of the mesentery enlarged, and hardened. In the year 1752, and beginning of 53, these malignant fevers, that put on the appearance of peripneumonies, became mortal in 7 days, and they discovered, that they were occasioned by a suppurative inflammation of the pericardium. Laxative medicines, quickened by an emetic, were most successful against these inflammations. About the end of the year 1753, and beginning of 34, these malignant fevers, which had their seat in the stomach, small guts, and partly in the lungs, ap- peared again, and seized a great number of persons of distinction. This cir- cumstance made them be considered as a new distemper by those who did not attend to it sooner; and the havock they had usually made, being rendered more remarkable by the quality of those who were the unhappy victims, gave the suspicion throughout Europe of having the plague. These reasons redoubled the diligence of the gentlemen of the faculty. The physicians met together, at their college, several times, to communicate their observations on these diseases. M. le Cat thinks they may be divided into 3 degrees. The patients of the first degree felt, at the beginning, a lassitude, and pain in the joints, attended with some fever, the fits of which went off by sweats. 4d2 573 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. They perfectly resembled those malignant, wandering, gouty rheumatisms of 1744. But these symptoms were of no long duration; they left the patients long interxals, in which they were able to rise out of bed. There was no great danger attending; and all that was terrible in them was this, that they were of long continuance. The disease of the 2d degree had, besides the foregoing symptoms, a continual fever, with exacerbations, and a pain in the head, that increased as the fever increased. That of the 3d degree began with the symptoms of the first, for 4, 5, and sometimes 8 days; after which it passed to those of the 2d, and was besides accompanied, in the exacerbations, with a cough, sore throat, nausea, a dry, black, and foul tongue; a delirium, or a tendency to it, in the height of the fits, followed by sweats ; a remarkable stupidity in the remis- sions ; in some a sinall oppression of the breast, with spitting of blood ; in others a swelled belly, which was slow in every evacuation, especially that of urine. Afterwards there often appeared the miliary eruption; some had a small flux, and blood was perceived in the stools. A great number were affected with a dejec- tion of spirits, and were struck with a sort of terror, as made them tremble at the sound of a common voice. These diseases ran through a course of 30 or 40 days, which he thinks may be divided into 4 periods. The first, or first 7 days, were passed with the symptoms of the first degree: the next 7 days with those of the 2d degree. In the 3d period, which consisted of about the same number of days, the patient laboured under all the symptoms of the complete disease. Towards the 21st the miliary eruption came on, which led the patient either to death on the 25th, or to recovery about the 30th or 40th day. Some patients, who were attacked with more violence, ran through all the stages in 7 days, as was remarked in 1752; and this short space brought some persons of the most vigorous constitutions to their graves. Many of their bodies were opened, on which they made the fol- lowing observations : In some, part of the villous coat of the stomach, and of the small guts, was inflamed; and the rest of these organs were filled with an eruption of the miliary crystalline kind, except that it was larger; and there was likewise an obstruction in the glands of the mesentery. In others, a strong inflammation had seized the whole stomach, and a small portion of the oesophagus ; but the intestines were free. These were filled with wind in those subjects whose bellies had been swelled. In those cases, wheie the delirium had continued long and violent, they found either ulceration on the stomach, or its villous coat separated, with a great inflammation, and even some gangrenous spots on the other coats of that organ. Nothing extraordinary was ever found in the brain. The most successful method of treating these disorders, was as follows: A VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 573 bleeding or two, at first, was directly followed by a * vomit. M. le Cat had seen this remedy produce a small flux of 5 or 6 stools a day, which, with the addition of lemonade, was generally sufficient to effect a cure. But when this success did not follow, the patient was bled first in the arm, then in the foot, and every 2 or 3 days there was given some cassia, quickened by an emetic, and dissolved in a decoction of tamarinds. They prescribed ptisans of strawberry- leaves, adding some nitre; lemonades, clarified whey, pure water by itself, a good many simple clysters ; draughts of the distilled water of borage and bugloss, sweetened with syrup of lemons and water-lily. Many did well with a simple julep of sugar and water, and a little wine. There were some, who, when they were just sinking, were raised again by cordials of the warmest kind, such as Venice treacle, given in large doses, and the preparation, called vinegar of the 4 thieves,-|* by spoonfuls, in broth. These medicines brought out a most plen- tiful miliary eruption, by which they were cured. The manner of recovery from this disease deserves a place in the history of it. There were but few, who recovered of it in the usual way, that is to say, who only wanted the restoration of their strength, exhausted as well by sickness as the medicines. Almost all of them, even those who had it in the first and se- cond degree, still felt some remains of the symptoms of the disease. Such pa- tients, as had any critical abscesses, were saved by this tribute only; but others, who escaped the mortality of this dangerous poison, carried about with them for \ several months, and still feel, its terrible effects; for to the usual weakness of convalescents were joined palpitations of the heart; a little of the painful lassi- tude in the joints, which was a sign of the first attacks of the disease; a slight pain in the head, but almost constant; an uncertain pulse; and, on the lessening or cessation of these complaints, they were replaced by wandering pains in the hypochondria, swimmings in the head, melancholy, and a remarkable disposi- tion to fear, being the remains of what constituted one of the characteristics of the disease. • It is called in the originalj I'emetique en lavage, which signifies an emetic well diluted with water; the formula of which is, 4-gr. of emetic tartar, dissolved in a quart of water; the 4th part of which is given at a time. After this has worked either by vomit or stool, another 4th is taken, and so on, till the patient is supposed to have vomited or purged enough. — Orig. + This is an infusion of several aromatic plants in vinegar. The reason of its being called vinaigre des quatre voleurs, is this : When the plague raged at Marseilles, 4 rogues broke into the houses of the sick, and carried off what they pleased, retiring to a secret place with iheir booty, and returned to the same business at different times, till they had amassed great riches ; but were at last apprehended, and hanged. Being asked, how they durst venture into the pestilential houses ? they said, they preserved themselves by drinking a glass of their vinegar twice or thrice a day, sprinkling their handkerchiefs and clothes with the same, and were not afraid. The French retain this name for it, though it is not in their dispen- satories, and use it as a high cordial. — Orig. 574 PHILOSOPHICAL TRANSACTIONS. [anNO 1755. XFI. An Account of the Death of Mr. George fVilliam Richman, Professor of Experimental Philosophy, a Member of the Imperial Academy of Sciences at Petersburg. Translated from the High Dutch, p. 6l. In order to demonstrate what Mr. R. might advance in an intended discourse with the greater certainty, he neglected no opportunity on the appearance of a thunder-cloud, diligently to discover its strength. Bars were standing for this purpose always on the roof of the house. These received the electrical power of the clouds, and imparted it to certain chains fastened to them ; by which it was conducted into one of his rooms, where his apparatus was. He was at- tending the usual meeting of the Academy the 26th of July 1753, a little before noon, when it thundered at a pretty distance, the sky being clear, and the sun shining. On this he hastened home, in hopes of confirming his former obser- vations, or possibly enabling himself to make new ones. The engraver So- kolow, who had the care of his future treatise, accompanied him, to make him- self the better acquainted with the chief circumstances of the electrical experi- ment, in order to be enabled to represent it more justly on a copper-plate. Mr. Richman carried the engraver immediately to his apparatus, taking notice of the degree of electricity on his bar, which was then only 4; and by which it appeared, that his bar had received very little from the thunder. He described to Mr. So- kolow the dangerous consequences which would attend the electrical power being increased to the 45th, or more degrees of his expositor. In the mean time the misfortune happened, about half an hour after noon, which cost Pro- fessor Richman his life. A thick cloud, that came from the north-east, and seemed to float very low in the air, was taken notice of by people walking in the street ; and these affirm, that they could plainly see, on the subsequent flash of lightning, and peal of thunder, a quantity of vaporous matter issue from it, which diffused itself in the circumjacent space. It was such a thunder-clap as has hardly been remembered at Petersburg. The serene weather continued af- terwards just as before. An English captain observed, that as the wind had been till then easterly, not long before the thunder it veered about to westward, but immediately after the stroke it returned to its former point, east. By this it ap- pears in what manner the inflammation of the electrical particles followed so quickly, the wind driving it against another cloud, not so pregnant with that combustible matter. The neighbours declare, that they saw through their \yin- dowsa vapour, in different rays, dart along the whole extent of the street ; and that wherever it touched the ground, it emitted every where sparks ; which is not incredible ; for there were people who, walking along between these rays of vapour, were quite stunned, and some beaten to the ground, though they speedily recovered agam. VOL. XLIX.3 PHILOSOPHICAL TRANSACTIONS. 5/5 A centinel in the Great Perspective*, not far from Mr. Richman's house, which stands at the corner of the said Perspective, was thrown some paces from his centry-box, but without receiving any injury. It is not therefore to be doubted but that this very thunder-cloud, or its electrical discharge, must have struck, the iron bars, which were on Mr. Richman's house-top ; by which a great part of the electric force was conducted, by means of the chains, to his electrical expositor; and thus it could not fail of having the melancholy effect, the parallel of which has not been known. According to the account of the engraver Sokolow, Mr. Richman inclined his head towards the expositor, to observe what degree of force it would have; and while he stood in that bent posture, a great white and bluish fire appeared between the electrical expositor and Mr. Rich- man's head. At the same time arose a sort of stream, or vapour, which entirely numbed the engraver, and made him sink down on the ground ; so that he can- not remember to have heard the loud thunder-clap. The iron ruler belonging to the expositor, which hung perpendicular, as it received all the force from the bars and chains, cast from it a thread, which was fixed to its top, and drove it up- ward towards the expositor. That this ruler might point out the degrees of strength, that for its more powerfiil operation, it stood with its lower end in a glass vessel, filled with brass filings. This ruler hanging right, a globular flame has been always produced, as well by artificial electricity as that of the clouds, which may be denominated natural electricity. This being now stopped, by the filings and glass vessel, from taking its direction aownwards, seems to have ex- panded itself round about the ruler, and by those bodies, incapable of electricity, to have been carried on towards Mr. Richman. And this is further confirmed, because they afterwards found the vessel broken in pieces, and the filings scat- tered about. The particulars, which happened to Mr. Richman, Mr. Sokolow is ignorant of. As soon as he had recovered his senses, he got up, and ran out •f the house, acquainting every one whom he met in the street, that the thun- der had struck into Mr. Richman's house. On the other side, as soon as Mrs. Richman heard the very loud stroke of thunder, she came hastening into the chamber, in which she conjectured she should see the bad consequences. She found her husband past sensation, sitting upon a chest, which happened to be placed behind him, and leaning against the wall ; which situation must have been occasioned by his falling back on receiving the electrical blow. He was no sooner struck than killed. There was not the least appearance of life. A sul- phureous smell, not unlike that which is caused by the explosion of gun-powder,, diffused itself through the whole house. Some servants, who were hard by in the kitchen, felt its effects, being quite stupified. The electrical expositor stood on * Probably a street so called. 576 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755, a low beaufet, upon which was likewise placed a China bowl that was cracked ; and there was such a shaking in the house, that the shock even stopped the movement of an English clock, or pendulum, which was in an adjoining room. There was no other inflammation happened in the house. But we have found another effect of the force of electricity, or of thunder-bolts, discoverable by the door-posts of the house ; for they were rent asunder length-wise, and the door, with that part of the posts, so torn away, twirled into the porch. The reason of which appears to be, because one of the above-mentioned chains, that were carried from the bars at the house-top to the expositor, passed very near them : and the kitchen door, being at a little distance off, had a splinter torn out, and dashed against a stair-case, that went towards the top of the house ; so that part of the elecrical matter seems to have taken its course this way, but without doing any more damage. They opened a vein of the breathless body twice, but no blood followed. They endeavoured to recover sensation by violent chafing, but in vain. On turning the corpse topsy-turvy, during the rubbing, an inconsi- derable quantity of blood fell out of the mouth. There appeared a red spot on the forehead, from which spirted some drops of blood through the pores, without wounding the skin. The shoe belonging to the left foot was burst open. Un- covering the foot at that place, they found a blue mark, by which it is concluded, that the electrical force of the thunder having forced into the head, made its way out again at the foot. On the body, particularly on the left side, were several red and blue spots, resembling leather shrunk by being burnt. Many more blue spots were afterwards visible over the whole body, and in particular on the back. That on the forehead changed to a brownish red. The hair of the head was not singed, though the spot touched some of it. In the place where the shoe was unripped, the stocking was entire; as was his coat every where, the waistcoat being only singed on the fore-flap, where it joined the hinder. But there ap- peared on the back of the engraver's coat long narrow streaks, as if red-hot wires had burnt off the nap. When the body was opened the next day, 24 hours afterwards, the cranium was very entire, having no fissure or cross-opening ; the brain as sound as pos- sibly it could ; the transparent pellicles of the wind-pipe were excessively tender, gave way, and rent easily. There was some extravasated blood in it, and in the cavities below the lungs ; those by the breast being quite sound, and not da- maged, but those towards the back of a brownish black colour, and filled with more of the above blood ; otherwise none of the entrails were touched ; the throat, glands, and the thin intestines, were all inflamed. The singed leather- coloured spots penetrated the skin only. In short, though one could trace out all the consequences of an instantaneous stroke throughout the whole body, yet many of them have not appeared to happen to others struck by thunder, when VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 577 they have been examined. Should not one therefore be led to conclude, that the electrical force, that occasioned Mr. Richman's death, must have been of a different substance from the common thunder-bolt ? That it was much more subtile, is obvious, because it left so few visible traces in the body, which it pe- netrated. Twice 24 hours being elapsed, the body was so far corrupted, that it was with difficulty they got it into a coffin. Mr. R. was born the 1 1th of July, 17 J 1, at Pernau, after the decease of his father, Mr. Wm. Richman, treasurer of the king of Sweden, who was carried off" by the plague, at the close of the year 1 7 1 0. Having laid the foundation of his learning at the Gymnasium at Revel, he prosecuted his studies at the uni- versities of Halle and lena, where he always made the mathematics and philo- sophy his principal objects. He was made a member of the Imperial Academy in the year 1735 ; extraordinary professor in 1741; and at last, in 1745, ordinary professor of experimental philosophy. XPII. Of a Roman Inscriptio7i found at Malton in Yorkshire, in the Year 1753. By John Ward, LL.D. Rhet. Prof Gresh. and P'.P.R.S. p. 69. This inscription was dug up in the Pye Pits, opposite the lodge at Malton, a town situated on the river Derwent, in the North Riding of Yorkshire. And the inscription, in words at length, may be read in the following manner : Diis Manibus. Aurelitis Macrinus, ex equitibus singutaribus Augusti. The peculiarity of this inscription, and what renders it remarkable, is the character of the person, to whose memory it was erected. These equites singu- lares are often mentioned in Gruter, Fabretti, and other collectors of ancient monuments ; but this is the first instance of them, which has ever occurred in any of our British inscriptions. Modern writers have differed very much in their sentiments, concerning the particular office and duty of this part of the Roman cavalry ; but Dr. W. thinks it most probable that these equites singulares made part of the emperor's body guards. Reinesius was of opinion, that they not only attended the emperors themselves, but also the governors of the Roman pro- vinces, in the like station ; though Fabretti, who has given a large collection of these inscriptions, declares that he had met with no sufficient evidence of this, either from ancient writers or inscriptions. Schelius, in his notes on this passage of Hyginus, thinks that they were first instituted by Augustus. And there is an inscription in Gruter, which mentions one of these equites singulares as having served under Augustus in several of his wars, and been rewarded by him. This account of the origin and station of that body of Roman horse may afford some light in settling the time, when this funeral monument of Aurelius Macrinus was erected. For if they always attended on the emjjeror himself, some one of the Roman emperors must then have been resident in Britain. And VOL. X. 4 E 578 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. as Severus resided here for about 3 of his last years, and died at York ; it seems most probable that this monument was set up within that time. And to this both the form of the letters on the inscription very well agree, and the ligature of the two letters G and A at the end of it. Fabretti observes, that these equites singulares had a burying-place allotted them at Rome, in the Via Labicana, not far from the sepulchre of the empress Helena. Several of their monuments have been found in that cemetery, adorned at the top with a human figure, lying on a couch ; and below the inscription, a horse with trappings, and a boy holding a whip. And if any such are met with elsewhere, they have, as he supposes, been removed from thence. Montfaucon has given a draught of one of those monuments, which contains the inscription recited above, and answers to this description of Fabretti, both as to the human figure, and that of the horse ; the former of which has a patera in the left hand, and a mask is suspended at each end of the couch ; and the boy, who is there wanting, he found on an- other. Those ornaments might very probably be omitted on such monuments, when erected in the provinces ; and it is plain there could not be room for the human figure above the inscription in this of Mai ton. At which place, as Mr. Borwick says in his letter, many urns, coins, and other remains of antiquity, have been found, in and about the Pye Pits ; whence he supposes it to have been a cemetery for some Roman garrison. In one inscription the emperor Commodus is himself called eques singularis, for the explication of which character recourse must be had to the accounts given by historians of his life and actions. And among other instances of his base and infamous conduct, he is said to have demeaned himself to that degree, as to act a part in most of the public games that were celebrated at Rome. Thus, one of his diversions was to attack wild animals in the amphitheatre ; at which ex- ercise he was so expert, as never to miss his aim in killing them, either with a javelin or an arrow. He would often combat with the gladiators, and was so fond of that character, that he assumed the name of one of them, who had been very famous. At other times he would act as a charioteer in the Circus. He joined also in the athletic exercises, and was at last strangled by a champion, with whom he had formerly engaged. Dr. W. does not find indeed, that he is ever mentioned by historians as a racer on a single horse, which is the character given him in the inscription ; as appears from Isidore, who calls them equites singu- lares, as distinguished from the desultores. But that horse-racing was also one of his recreations, we learn from a passage in Dion Cassius ; who says that Commodus came once to Rome on a sudden, when he was not expected, and exhibited a race of 30 horses in the space of 2 hours. It is not improbable therefore, that he might sometimes take a part in that exercise, as well as in those above mentioned. And as he affected to have all his actions, however shameful or ridiculous, publicly I VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 579 recorded, this inscription might have been erected in compliment to him under that character. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the Royal Society, by the Company of Apothecaries for the Year 1745, Pursuant to the Direction of Sir Hans Sloane, Bart. &c. p. 78. [This is the 33d presentation of this kind, completing to the number of l650 different plants.] XIX. On the Advantage of taking the Mean of a Number of Observations, in Practical Astronomy. By T. Simpson, F. R. S. p. 82. It is well known that the method practised by astronomers, to diminish the errors arising from the imperfections of instruments, and of the organs of sense, by taking the mean of several observations, has not been so generally received, but that some persons of note have publicly maintained, that one single obser- vation, taken with due care, was as much to be relied on, as the mean of a great number. As this appeared to be a matter of much importance, Mr. S. was in- clined to try whether, by the application of mathematical principles, it might not receive some new light ; whence the utility and advantage of the method in practice might appear with a greater degree of evidence. But the rest of this paper will be better consulted in Mr. Simpson's Miscel- laneous Tracts, published in 1757, where the paper is much improved. From a particular example which Mr. S. calculates, he infers that the chance, for an error exceeding 2 seconds, is not -^ part so great from the mean of 6, as from one single observation. And it will be found, in the same manner, that the chance for an error exceeding 3 seconds, will not be t-bVo P^rt so great from the mean of 6, as from one single observation. On the whole of which it appears, that the taking of the mean of a number of observations, greatly diminishes the chances for all the smaller errors, and cuts off" almost all possibility of any great ones : which last consideration alone seems sufficient to recommend the use of the method, not only to astronomers, but to all others concerned in making ex- periments of any kind, to which the above reasoning is equally applicable. And the more observations or experiments there are made, the less will the conclusion be liable to err, provided they admit of being repeated under the same circum- stances. XX. Of the Success of Agaric, and the Fungus Finosus, in Amputations. By Mr. James Ford, Surgeon, of Bristol, p. 93. Mr. F. here gives an account of 2 cases of amputation, in which the agaric was successfully employed as a styptic. 4 £ 2 580 PHILOSOPHICAL TRANSACTIONS. [aNNO 1735. XXL Queries sent to a Friend in Constantinople. By Dr. Maty, F. R. S. and answered by James Porter, Esq. F.R.S. Embassador there, p. 96. 1 . Whether we may know with any certainty, how many people are generally carried off by the plague at Constantinople ? 2. Whether the number of in- habitants in that capital maybe ascertained? 3. Whether what has been ad- vanced by some travellers, and from them assumed by writers on politics, be true, that there are more women than men born in the east? 4. Whether plurality of wives is, in fact, as it was confidently afHrmed to be, in the order of nature, favourable to the increase of mankind? 5. What is the actual state of inoculation in the East? 6. What is become of the printing-house at Con- stantinople ? and are there any original maps of the Turkish dominions, drawn from actual surveys ? 7 • What sort of learning is cultivated among the Greeks, and among the Turks ? To these 7 queries Mr. Porter made the following answer : 1 . The only plague, which he observed at Constantinople, in the course of 7 years, was that of the year 1751 : there are almost annually dispersed accidents, some perhaps real, some suggested by trick and design, to serve sinister purposes. '2. The Turks have no register, no bills of mortality : they are prohibited, by their law, from enumerating the people. He applied to the Reis Effendi, and other ministers of the Porte, to know what probable calculation they could make concerning the number of dead; but they all concurred in one general answer, that they had no other but what was founded on the decrease of the consumption of the quantity of corn, or bread ; and in general talked of about 1 50000. Corn is delivered out by an officer of consideration, and an exact register kept. Be- fore the commencement of the plague, in March and April 1751, the consump- tion of corn was IQOOO measures, called khilos. On its continuance and decrease it diminished to 170OO, and on its total cessation, it was found not to amount to above 14000. A khilo weighs 22 okes. It is ground to 18 okes of flour. The bakers have generally the secret to make out of this last quantity 27 okes of bread. They add to an oke of flour one of water, besides some salt ; and as their bread is almost dough, few of the watery particles are exhaled ; and it is esteemed good if it is not doubled in quantity, when taken out of the oven. The people live principally on bread ; the poorer with onion, garlick, fruits, or pulse, according to the seasons ; the others with very small portions of flesh, or fish. The more laborious professions, as labouring men, stone-cutters, car- penters, &c. eat from 2 to 2^ okes a day ; the other, according to the common run of families, composed of men, women, and children, half an oke each ; so that the lowest calculation, on a medium, may be about an oke and a quarter daily, eaten by each person at Constantinople. But should it be thought too VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 58 I much, an oke, which is 1^ lb. English, he supposes nearer truth : the following conclusions then will result : That therefore on the highest number of 19OOO X 27, we have 513000, the quantity of okes of bread consumed, and consequently the number of souls at Constantinople. That on the decrease of the plague to 17000, 54000 persons were either dead or missing. That when the quantity was reduced to 14000 on the cessation, those either fled or dead amounted to 135000. It is said by some, that Constantinople contains near 3 millions of inhabitants ; but on whatever supposition we take the consumption of the quantity of bread, that quantity will be found erroneous. On a gross calculation made by some of the principal men, and particularly the Chiorbachees, or colonels of Janizaries, who had their stations at the most noted and only places where the funerals pass, they reckoned for 6 weeks, while the plague was at its height, and in its crisis, from 900 to 1 000 per diem ; and that the whole amount of the dead in that time might be about 40000: and from the time it wis in its increase and decline, they added 1 5 to 20000 more. If therefore we admit 60000 in the whole, it will be as that sum to 513000, or as 1 to 8±-l. There is a remarkable coincidence between this proportion, and the number of dead which was carried out of the Adrianople-gate, during 1 2 days, the same season of the year 1752; and of the like number of days in 1 75 1 . Hence the number of dead, at least through that gate, in time of common health, was to those in that of sickness, as 59 to 489, o^ ^s 1 to 8^, nearly. The Adrianople gate is reckoned the greatest passage for the dead, on account of its vicinity to the most extensive burial-places. A great deduction must be made for the vast decrease of the consumption of wheat towards the cessation of the plague, from the considerable numbers, who fled into Asia, the islands of the Archipelago, ^nd Romelia. It is extremely difiicult, if not impossible, to come at any other computus of the number of inhabitants, much more so of houses, at Constantinople. The city is divided somewhat in the manner it was under the Grecian empire, that is, into different quarters, called Mahales, and each under the special direction of an Imaum. As far as it extends to their immediate advantage, they are in- formed of the number of families in their district ; but whoever would dare to collect from them, might not only risk the censure of the government, but his head. Besides, if the inquiry is general concerning houses, it is impossible to fix a determined idea ; they confound palace, seraglio^ shop, room, and call them indiscriminately houses. The Jews say, that they have lOOOO houses at Constautmople : but in what we call a house, there are perhaps 10 families, and the distinct number of the latter they dare not mention.. Mr. P. endeavoured with persuasion, and all his weightj to induce the Greek and Armenian patri- 582 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755, archs, to obtain for him a register of the births and burials of their respective communities; but at length they acknowledged it impossible. Their parishes are farmed to curates, by the diocesan bishops ; the income arises from births and burials; so that to conceal the former, they must likewise the latter; and they never exhibit a faithful register. 3. That there are more women than men born in the east, seems a figment of travellers, rather than founded in truth ; it is scarcely to be known where poly- gamy is lawful. The apparent conclusion may seem natural, because many of the harems of the opulent, especially in the great cities, are numerous : but these are not composed of the natives of those cities, but are brought from countries where the Christian rites are observed ; in time of peace, from Georgia, and in war from Hungary and Russia, &c. so that if more women are found in such fa- milies than men, they must be considered as an extraneous production annually or daily imported. 4. Mr. P. affirms it as a truth, that in general, Mahometans, notwithstand- ing their law^ procreate less than Christians. The rich, who are the only persons that can maintain concubines, have seldom 4 or 5 children. Few exceed 2 or 3; many of the former, and most of the middling and poorer sort, have generally but one wife. The latter indeed exchange them with facility ; but yet we do not perceive they have a numerous progeny. He thinks this arises from a cause different from that which is commonly assigned, not from their being enervated by variety, but rather from their law. The frequent ablutions, required by the doctrine of purity and impurity, perhaps may check the natural passion ; or when it is at its height, they find themselves prohibited enjoyment. 5. Inoculation is practised at present among the Greeks, and, notwithstand- ing religious scruples, among the Romanists : with the few he had known, it generally succeeded ; but the numbers will not admit of comparison. There are not perhaps 20 in a year inoculated. The Timoni family pretend, that a daughter had been inoculated at 6 months old, but afterwards acquired the small- pox in the natural way, and diet! at 23 years. The evidence is doubtful. Ti- moni's account is incorrect ; his facts are not to be depended on. Pylarini's is more exact. It was neither Circassians, Georgians, nor Asiatics, who introduced the practice. The first woman was of the Morea ; her successor was a Bosniac; they brought it from Thessaly, or the Peloponnesus, now Morea. They pro- perly scarified the patient, commonly on many parts, sometimes on the forehead, under the hair, sometimes on the cheeks, and on the radius of the arm. A father told Mr. P., that the old woman not being able, through age, to make the incision on his daughter, with the razor, he performed that operation. The needle has also been used. The Turks never inoculate : they trust to their fatum. Whence the method had its origin seems here unknown. A Capuchin VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 583 friar was on a mission in Georgia for above l6 years ; he has returned about 2 years ; he is a grave sober man, who gives an historical account of the virtues and vices, good and evil, of that country, with plainness and candour. The usual introduction and security of these missionaries is the pretence to the practice of physic, that in destroying bodies they may save souls : so that this honest man, who is extremely ignorant, was in high reputation both as physi- cian and confessor. It was therefore impossible, as he himself observes, that either the public or private practice of inoculation could be concealed from him ; but he has most solemnly declared to Mr. P. repeatedly, that he never heard one word about it at Akalsike, Imirette, or Tifflis ; he is persuaded, that it has never been known among them. He has often and frequently attended the small-pox, which is almost certain death there ; and generally, if not always, of the confluent kind. 6. Printing was introduced by an Hungarian renegado, who called himself Ibrahim EfFendi : it had no long continuance. The copies are not many, and are now very dear and scarce ; few even to be bought. The maps did not exceed 3 or 4; one of Persia, one of the Bosphorus, and one of the Euxinus, or Black- sea ; they are not to be found but in private hands. All our maps of these countries are extremely imperfect and incorrect. The jealousy and superstition of the people, though the government should permit Christians to raise any printing-house, would be an irresistible impediment ; and they are too ignorant themselves to be ever capable of doing it. The adoptive son of this Ibrahim EfFendi, who bears the same name, is secretary under the interpreter of the Porte ; he has all the materials for printing, but never could find, since his father's death, and during Sultan Mahmud's reign, money to carry it on. The question is now, whether Sultan Osman is not too strict a mussulman to continue the permission. 7. The progress of arts and sciences, and literature, seems travelling on, gra- datim, to the westward, from Egypt to Greece, from Greece to Rome, thence to the west of Europe, and he supposes at last to America. We find few traces in the east : the Greeks, who should be the depositaries of them, are the same Greeks they ever were. Homines contentionis cupidiores quam veritatis. They have retained all the vices, imperfections, ill habitudes, of their ancestors ; but have lost all their public spirit, and public virtues. The clergy, who should support the whole machine of learning, are themselves the source of ignorance; all their talents and acquisitions consist in bribing among the Turks, and sollicit- ing to destroy one patriarch, in order to make another ; to raise from a curacy to a bishoprick, and to exchange from an indifferent one to a better. They endeavour to cultivate literal Greek, and some study it, but advance no further. There are neither grammarians, critics, historians, nor philosophers, among 584 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. them; nor have they proper preceptors or masters to instruct. They have formed a sort of an academy at Mount Athos, for their youth, which will scarcely sur- vive the person who has undertaken it : he has himself but the mere elements of science. However, his desire of knowing may improve him ; and he may per- haps lay the foundations in some youth with success. The Turks have many books among them, though exceedingly dear ; folios he had seen cost 100 to 2 and 300 dollars each; i.e. from 15l. to 45l. The few printed folios, some of which he picked up some years before, cost 5l. to 61. sterling. Their scribes spend many years about a few copies. Their learning consists principally in abstruse metaphysics : some few touch the surface of science. He had looked out with great industry for old Arabian manu- scripts in the mathematical way : what they brought him were translations of some propositions of Euclid, Theodosius, Archimedes, and ApoUonius. They have some parts of Aristotle ; but their favourite philosophy is the atomical or Epicurean, which with them is called the Democritical, from Democritus. Many of their speculative men have adopted that system, and conform to it in their secret practice. The institutes and practice of physic are taken from Galen. Eben Zyna, or Avicena, is a principal guide : Mathiolus is known. But with all this, as the sole drift and end of their study is gain, there does not seem the least emulation towards true knowledge : so that the state of letters may be said to remain deplorable, without the least glimmering or remote prospect of a recovery., P. S. Mr. P. corrects the report of the Capuchin concerning inocula- tion in Georgia. One of their physicians, a most ignorant fellow, who lives by his profession here, avers that, among those who follow the true Greorgian rites, not Romanists, the practice is common. It has its rise from mere superstition. He tells us, " That the tradition and religious belief of that people is, that an angel presides over that distemper ; that therefore, to show their confidence in him, and to invite him to be propitious, they take a pock from the sick person, and, by a scarification, they insert it in one in health, generally between the fore-finger and thumb. It never misses its effect, and the patient always recovers. To attract the angel's good-will more effectually, they hang the patient's bed with red cloth or stuff, as a colour most agreeable to him. He has been assistant to this practice, and declares it to be common." The Capuchin acknowledges, that it might be among the Georgians the Doctor men- tions, and not have fallen under his knowledge. XXII. Extracts of Two Letters to Thomas Mollis, Esq. concerning the late Discoveries at Herculaneum. p, lOQ. Near the royal palace at Portici, has been discovered a large garden, with a palace belonging to it. In one room of this palace was found a mosaic pavement. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 585 made up of different coloured stones. It represents a city surrounded with walls, having 4 towers, one at each corner ; and has since been taken up, to be placed with other beautiful antique pavements in the king's galleiy. Extract of a Letter Jrom Camillo Paderni, dated at Naples, Jan. 1755. October '22, 1754, was found a bust in bronze, larger than the life, and of excellent Greek workmanship ; which from some circumstances may be thought to be a Syrian king. It has eyes of white marble, like many other busts, which have been met with. November 27, was discovered the figure of an old fawn, or rather a Silenus, represented as sitting on a bank ; with a tyger lying on his left side, on which his hand rested. Both these figures served to adorn a foun- tain, and fi-om the mouth of the tyger had flowed the water. This Silenus was of bronze, and of good workmanship. The head was crowned with ivy, the body all over hairy, and the thighs covered with a drapery. From the same spot were taken out, November 29, three little boys of bronze, of a good manner. Two of these are young fawns, having the horns and ears of a goat. They have silver eyes, and each a goat-skin on his shoulder, in which they anciently put wine, and through which here the water issued. The third boy is also of bronze, has silver eyes, is of the same size with the two for- mer, and in a standing posture like them, but is not a fawn. On one side of this last stood a small column, on the top of which was a comic mass, that served as a capital to it, and discharged water from its mouth. All the figures before described are two palms in height without their bases. • December 16, in the same place were discovered another boy, with another mask, and 3 other fawns ; in all respects like those which were found the 27 th and 29th of November, except that there was no tyger. Besides these, they met with 2 little boys in bronze, somewhat less than the former. These like- wise were in a standing posture, had silver eyes, and held each of them a vase, with handles, on his shoulder ; hence the water flowed. They also dug out an old fawn, crowned with ivy, having a long beard, a hairy body, and sandals on his feet. He sat astride on a large goat skin, holding it at the feet with both his hands, from which had issued a larger quantity of water than from the others ; though the fawn himself is of the same size with the former. All the above-mentioned figures were taken out of a place not exceeding 8 palms square, and were covered with the ruins of the building ; for they were not in a garden, but in a room paved with mosaic work, the remaining part of which we are now going on to examine. We have likewise found a large quantity of household furniture, made of earthen and iron ware, and some glass. vox.. X. 4 F 586 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. XXIll, On the Boohs and Ancient Writings dug out of the Ruins of an Edifice near the Scite of the old City of Herculaneum. Translated by John Locke, Esq.F.R.S. p. 112. Within 1 years last past, in a chamber of a house, or more properly speaking, of an ancient villa, in the middle of a garden, has been found a great quantity of rolls, about a palm long, and round; which appeared like roots of wood, all black, and seeming to be only of one piece. One of them falling on the ground, it broke in the middle, and many letters were observed, by which it was first known, that the rolls were of papyrus. The number of these rolls, were about 150, of different sizes. They were in wooden cases, which are so much burnt, as are all the things made of wood, that they cannot be recovered. The rolls however are hard, though each appears like one piece. The king has caused in- finite pains to be taken to unroll them, and read them ; but all attempts were in vain; only by slitting some of them, some words were observed. At length Sig. Assemani, being come a second time to Naples, proposed to the king to send for one Father Antonio, a writer at the Vatican, as the only man in the world, who could undertake this difficult affair. It is incredible to imagine what this man contrived and executed. He made a machine, with which, by the means of certain threads, which being gummed, stuck to the back part of the papyrus, where there was no writing, he begins, by degrees, to pull, while with a sort of engraver's instrument he loosens one leaf from the other, which is the most difficult part of all, and then makes a sort of lining to the back of the papyrus, with exceedingly thin leaves of onion, if I mistake not, and with some spirituous liquor, with which he wets the papyrus, by little and little as he un- folds it. All this labour cannot be well comprehended without seeing. With patience superior to what a man can imagine, this good father has unrolled a pretty large piece of papyrus, the worst preserved, by way of trial. It is found to be the work of a Greek writer, and is a small philosophic tract, in Plutarch's manner, on music; blaming it as pernicious to society, and productive of soft- ness and effeminacy. It does not discourse of the art of music. The beginning is wanting, but it is to be hoped, that the author's name may be found at the end ; it seems however to be the work of a stoic philosopher ; because Zeno is much commended. The papyrus is written across in so many columns, every one of about 20 lines, and every line is the 3d of a palm long. Between co- lumn and column is a void space of more than an inch. There are now unrolled about 30 coiumns; which is about a half of the whole; this roll being one of the smallest; the letters are distinguishable enough. Father Antonio, after he has loosened a piece, takes it olF where there are no letters ; and places it be- tween two crystals for the better observation; and then, having an admirable talent in imitating characters, he copies it with all the lacunae, which are very VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 587 numerous in this scorched papyrus, and gives this copy to the Canon Mazzocchi, who tries to supply the loss, and explain it. The letters are capital ones, and almost without any abbreviation. The worst is, the work takes up so much time, that a small quantity of writing requires 5 or 6 days to unroll, so that a whole year is already consumed about half this roll. The lacunae, for the most part, are of one or two words, that may be supplied by the context. As soon as this roll is finished, they will begin a Latin one. There are some so voluminous, and the papyrus so fine, that unrolled they would take up 100 palms space. XXIV. On the several Earthquakes lately felt at Constantinople. By James Porter, Esq. p. 115. This paper is quite unimportant, containing only some trite remarks on the wind and weather, and accounts of some very trifling earthquakes that lately happened, with no circumstances of any consequence. XXV. Letters of Henry Eeles, Esq. concerning the Cause of the Ascent of Vapour and Exhalation, and those of Winds; and of the general Phenomena of the fVeather and Barometer, p. 124. It is agreed, that the ascent of vapour and exhalation through the air may be effected in two ways, by impulse, and an alteration of their specific gravity. That vapour does not generally ascend by impulse, may be proved by many fami- liar experiments, viz. put boiling water into a vessel; then empty it, and hold the vessel with the aperture downwards; the vapour, which is afterwards expelled from the vessel, must be in a direction downward; but we find, that as soon as it has got but a very little below the rim of the vessel, it has its direction altered, and ascends by the laws of specific gravity. The same thing may be observed in all boiling vessels, where the vapour is emitted in a direction downward; or, in cold weather, when the vapour of a man's breath may be seen, let him breathe downward, and the direction of his breath will be presently altered, as in the former case. Since then vapour ascends without any other impulse than that which is incident on all bodies ascending by the laws of specific gravity; it is necessary to inquire, how the specific gravity of vapour is altered, to cause its ascent. This is generally supposed to be done by filling vesicles of water with rarefied air, till the diameter of the vesicle be 10 or more times the diameter of a drop of water, composed of the same constituent particles ; and that the vesicle, by this means, becomes specifically lighter than air. But Mr. E. thinks that this cannot be done so easily as it has been generally imagined; and when done, it will not be sufficient for the purpose; which he infers from the following consi- derations. First, the great difficulty in forming those vesicles, especially of the particles of dry bodies carried off by exhalation, and filling them with rarefied 4f 2 588 PHILOSOPHICAL TRANSACTIONS. [anNO 1755. air, while the exterior air remains condensed. Secondly, that there is not any allowance made for the weight of the included air. Thirdly, the constituent particles of water are but very little, if at all altered in their specific gravity. Fourthly, that this thin vesicle can never be a sufficient boundary between the exterior condensed air and the interior air, so exceedinglv rarefied. Rejecting these popular opinions, as to the cause of the ascent of vapours and exhalations, Mr. E. observes that it now remains to inquire, by what means this may be done ; since neither impulse, rarefaction of the air, nor any formation of their parts by expansion, seem sufficient for the purpose. There appears to him but one way of altering the specific gravity of the particles of vapour and exha- lation, to render them lighter than air, which is by adding to each particle a suf- ficient quantity of some fluid, whose elasticity and rarity are exceedingly greater than that of the air. That the fluid or fire of electricity is such, will be easily granted; but how far it is adapted to this purpose, we must inquire from expe- riments. For the purpose is great; no less than all vegetation and animal life depending on the ascent and descent of vapour and exhalation. Mr. E. says he has made some experiments, by which it appears that all fumes arising from fire, whether blazing or otherwise, and all steams rising from boiling or warm waters, and from all other fluids, and the breath of man, and of all other animals, and all the effluvia thrown oft' by perspiration, are strongly elec- trified. But he now only mentions a few. First, that desultory motion, by which it flies ofl^ from an electrified body to any number of non-electrics, which are brought within the sphere of its activity and affection, till it be equally dif- fused through all. Secondly, that the sphere of its activity is increased by heat. Thirdly, that this fire does not mix with air. Fourthly, that it intimately per- vades water, and many other bodies, covering their superficies to a certain dis- tance; which distance is not in proportion to the bulk, of the body electrified, but in proportion to the state of activity of the electrical fluid. Fifthly, this electrical fluid readily joins with any fire which fumes, or rather with the blaze or fumes of, any fire; but will not mix or fly oflT with the fire of red-hot iron, or any other metal, which does not fume. Now, to show that this electrical fire or fluid is the principal cause of the as- cent of vapour and exhalation, we need only prove that it attends all vapour and exhalation, and that in such quantity, as is necessary to render them specifically lighter than the lower part of the atmosphere. He does not undertake to deter- mine, by what cause vapour and exhalation are detached from their masses, whether by the solar or culinary fire, or by the vibrations of the electrical fluid rendered more active by those fires; though he thinks the latter. But it is evi- dent, that they are emitted in exceedingly minute distinct particles, and that these particles must pass through that electrical fluid; which surrounds the sur- VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 589 face of the mass; and that, by that means they must be equally electrified with the mass, that is, they must be covered with the electrical fluid to as great a distance from their superficies as the mass is covered ; which must always be in proportion to the state of activity of the electrical fluid. In which state, when they have passed the surrounding fluid, they must be repelled by it; and also repel each other; and if each particle of vapour, and its surrounding fluid, oc- cupy a greater space than the same weight of air, they must be fitted to ascend till they come in equilibrium with the upper and rarer part of the atmosphere; where they must float, till their specific gravity is altered. As it is very difficult to assign the magnitude of each particle of vapour and exhalation, and that of the surrounding fluid; and to show that both, taken together, occupy a greater portion of space than the same weight of air; we can only apply to experiment, to show that it is possible that it may be so; and that will show, that in all pro- bability it is so; since it is evident, that every particle must be endued with a portion of this electrical fire or fluid; and that there is not any other sufficient cause assigned for their ascending. It is evident, that on electrifying any light matter, such as down, or the downy parts of feathers, their specific gravity is much lessened; and that, by holding another electrified body under them, .they may be driven upwards at pleasure. It is also evident, from experiment, that the more you divide the parts of such bodies, the more of their specific gravity they will lose by being elec- trified ; and by dividing them into very minute parts, that they ascend to a con- siderable height after they are electrified. Hence he thinks it highly probable, that the exceedingly small particles of vapour and exhalation may be, and are, sufficiently electrified, to render them specifically lighter than the lower air; and that they do ascend by that means. And that they will ascend proportionally higher, as the surrounding fluid is proportionally greater than the particle which is carried up. Mr. E. then endeavours to show that the ascent and descent of vapour and exhalation, attended by this fire, is the principal cause of all our winds. It being admitted that wind is only air put into motion, many have been the con- jectures how that motion is caused. Among which, the motion of the earth, and the air's being rarefied by the sun, seem to stand first. The trade winds being most regular, and occupying a considerable part of the globe, it has been thought proper first to account for them, from the afore-mentioned causes. But he thinks that these causes, by themselves, are not sufficient for the motion of those winds, and much less so for the irregular motion of all the other winds. If the apparent motion of the air was occasioned by the diurnal revolution of the earth from west to east, by the air's being left behind, the motion must be found more regular, and very different from what it is; for in that case the SQO ■ PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. greatest motion must be at the equator, and from thence lessen gradually to the poles; and must be continued always equally one way, both day and night, and at all seasons. But we find quite the contrary: the most gentle gales blowing at the equator and between the tropics pretty steadily, one way all day long, and dying away at night; while high winds and storms, blowing all manner of ways, are found in the higher latitudes. Neither does he think that the sun's rarefying air can simply be the cause of all the regular and irregular motions found in the atmosphere; but he thinks the cause is the ascent and descent of vapour and exhalation, attended by the electrical fire, or fluid. Now, all the vapour and exhalation, raised in the torrid zone, being buoyed up by the electrical fire, must add a column to the air, though of a different matter, at least 1000 times greater than the vapour and exhalation taken up; which column must necessarily force the adjacent part of the incumbent air up- wards, and must as necessarily be reacted on by the incumbent air, to restore the equilibrium of the whole air. And as it cannot be readily forced down again, it must float off, at that altitude, toward those parts where little or no addition has been made to the atmosphere ; and by that means must propel the air on the horizontal level with it, and that below it, as it is itself propelled by the weight of the incumbent air. And that motion must be from the equator, where the greatest quantity of vapour, &c. is raised, toward the poles, and partly to the west; as the column of vapour is always rising from east to west, as the earth turns toward the sun. For here we must confess, that the sun is the great agent in detaching vapour and exhalation from their masses; whether he acts immedi- ately by himself, or by his rendering the electric fire more active in its vibrations; but their subsequent ascent Mr. E. attributes entirely to their being rendered specifically lighter than the lower air, by their conjunction with this electrical fire. The fire, which surrounds the vapour, beginning to condense, and the vapour to subside, in passing the tropics, becomes a greater pressure on the air beneath, and by that means forces some part back into the tropics, in the place of that air protruded by the ascent of the vapour, &c. and the remainder in a direction toward the poles. The common rotation of the air in coming in below, to supply the place of that part carried up by any fire, may explain this motion. To show how this motion must tend to the west, we must consider, that the column of air, raised by the ascending vapour, &c. is at its greatest altitude to the east, and therefore must press that air to the westward, which is continually protruded by the vapours, &c. beginning to ascend from east to west; and the compressed air at the tropics must tend to the westward, till their forces meeting make the motion entirely to the west. The air itself being rarefied, and carried up by the reflection of the intense heat of the sun, may be a considerable addi- tional cause of these trade winds; but never can be the sole cause of all the r yOL. XUX.] PHILOSOPHICAL TRANSACTIONS. SQl erratic winds. To account for all the irregular winds within the tropics, he says, that where such happen, it must be by means of some tracts of land, which rise to a greater height above the horizontal level, than vapours generally do; by which the motion of the vapours is stopped, and the vapour accumulated by succeeding vapour, and the air, on which they float, is of consequence pressed into a new direction. And from hence may also be explained the cause of the rains, particularly so called in the sea language. He next considers what becomes of the vapour, &c. floating from over the tropics toward the poles; which being less affected by the heat of the sun, re- flected from the surface of the globe, the surrounding electrical fire begins to condense more and more as it moves toward the poles, and the vapours of course to descend; and that part most, which is most remote from, or is farthest left behind by the sun; and of consequence the higher column of air must tend that way to restore the equilibrium ; which motion, at this side the equator, must be to the north-east; and as the vapour, &c, fall again to the earth, the motion must be more to the east. Hence our south-west and westerly winds, which blow a considerable part of the year. But as this system is too regular to account for the phenomena of the erratic winds, he considers whence they arise. He had before observed, that tracts of land rising into the atmosphere will stop the regular motion of the vapour, &c. and that the vapour being accumulated by succeeding vapour, the subjacent air must be pressed into new directions Now this cause, added to the daily dilata- tion of the electrical fire, and the contraction at night, and the coalition of the vapours, to occasion their total descent, will be sufficient to produce a very great variety of winds on this side the tropic. It now remains to show, how the general phenomena of the weather and baro- meter arise from this system. First, Why it generally rains in winter, while the wind is south, south-west, and westerly. Secondly, Why north-west winds are generally attended by showers in the beginning, and become more dry, as they are of longer continuance. Thirdly, Why north and north-east winds are generally dry. Fourthly, Why the east wind continues dry and dark for a con- siderable time together. Fifthly, Why squalls precede heavy and distinct showers; and why a calm ensues for some little time after they are passed. Sixthly, Why storms and high winds seldom happen in a serene sky without clouds. Seventhly, Why the vapours, in warm seasons, coalesce to form those distinct dense clouds, which produce thunder and heavy showers. Eighthly, Why the barometer falls lowest in long continued rains, attended by winds; ana why it rises highest in long continued fair weather; and why the intermaliate changes happen. Ninthly, Of land-breezes and sea-breezes, and water-spouts. First, the vapours passing the tropics into colder regions, have their sur- 592 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755, rounding fire condensed by degrees ; which must increase their specific gravity, and lessen their repulsive power : by which means they must both descend and approach each other, till at last they form dense visible clouds ; and these clouds are also accumulated by other succeeding vapours, of like specific gravity, till they form clouds, which are often several hundied yards in depth, as is often seen in passing through them up the sides of very high mountains. In clouds of such depth, he thinks the coalition of their particles to form drops, may arise from their motion, and the order of specific gravity. Hence he thinks the excess of electrical fluid will run off among the other particles; by which means the en- larged particles have their specific gravity increased, and are enabled to descend to a lower region of the air. And the more particles they impinge on, in their descent, the more their specific gravity and velocity will be increased ; and the more their velocity is increased, the more particles will they impinge on, till they fall from the clouds in drops; whose size will be according to the depth and den- sity of the cloud they have passed through. Having remarked on several of the other particulars above enumerated, in a diffuse and uninteresting manner, Mr. E. then adverts to something of land- breezes and sea-breezes, a phenomenon which sometimes happens in fair settled weather, when the wind blows out from the land at night, and in from the sea at day-time. The land-breeze is occasioned by the descent of the clouds, and the particular formation of the land; for if the land rise into a hilly country from the sea, when the clouds and vapours ascend at night, which they often do by the electrical fluid being condensed, they must press the air down the land to- ward the sea in their fall; as may appear from the smoke of any fire running down the side of a hill, in the evening of a damp day, when the clouds are on the descent. And the sea-breeze is occasioned by the clouds ascending in the day-time, which must impel the incumbent air upwards, and make room for the sea-breeze to flow in ; but, beside the mere ascent of clouds, there is an exceed- ingly greater quantity of vapour raised from the land than from the sea. For the same extent of land has an exceedingly greater surface than the same extent of sea ; which may appear from the various forms of vegetables and animals, &c. and the greater the surface, the greater will be the evaporation. Beside, the more irregular these surfaces are, the greater will be the reflection and refraction of the sun's beams, which will increase their power. And it is also necessary that the evaporation should be much greater from vegetable and animal fluids, than from fluids in a quiescent state, to carry on a circulation for the great work of nutrition. Now the ascent of these vapours must beget a circulation of the air inward from the sea ; in the same manner as the ascent of vapours fi-om any fire brings in the air below to that fire. As to water-spouts, he says they are oddly described by the learned, as being VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 5g3 great columns of water sucked up from the sea by the clouds. But he says he never saw any such; nor could he find, on inquiry from many honest men, who have sailed almost all the known seas, that they ever met any such; and there- fore he does not believe that there are any such. There is indeed an appearance something like their description, which may have given rise to their conjectures; but this is no more than a very heavy shower from a very dense cloud, which is drawn into a conical form, and a very narrow compass at bottom, before it arrives at the sea, which it dashes with great violence in its fall. Dr. Birch, the secretary, by order of the Society, having desired to know the experiments, by which Mr. E. found all ascending vapours and exhalations to be electrified; answers, at first he only supposed they must be so, according to the reasonings in his letter; but on trial, with a very simple apparatus, he convinced himself that they were so. He extended a fine string of silk, 8 feet horizon- tally, and from the middle suspended 2 pieces of such down as grows on the turf-bogs, by 2 pieces of fine silk, about 1 2 inches each in length ; and then, by rubbing a piece of sealing-wax on his waistcoat, he electrified the pieces of down; and then brought sundry burning things under them, so as to let the smoke pass in great plenty through and about them, to try whether the electric fluid would run off with the smoke; but he observed that the down was but a little affected by the passage of the smoke, and still remained electrified. He then brought sundry steams from the spout of a boiling tea-kettle, and other- wise, in the same manner, and still found that the down remained electrified. He then breathed on them in great plenty, but found that the down still remained electrified. He then joined the palms of his hands together, with the fingers extended perpendicularly under the down, which still remained electrified ; though the subtile effluvia, thrown off by perspiration, passed in great plenty through the down; as may appear by holding one or both the hands in the same manner under any light matter floating in the air, which will be driven upward, with as great velocity as an electrified feather is by any electrified body held under it. The electricity remaining in the electri fied down after these experiments, made it appear that the smoke and steams must be either electrics, or non-electrics electrified. It was easy to suppose them non-electrics, as they arise from non- electric bodies; and the more, because the highest electrics by a discontinuity and comminution of their parts, long before they come to be as minute as the particles of ascending vapour, become non-electrics, or conductors of electricity. For glass, resin, wax, &c. all become non-electric, even in fusion. But to try whether the steams, &c. were non-electrics, he only bedewed the wax and glass with his breath, steams, &c. from his hand to the end of the wax and glass ; and then touching the electrified down with the end of the wax or glass, he found that the electrical fire immediately passed from the down into his hand, through VOL. X. 4 G 594 PHILOSOPHICAL TRANSACTIONS. [aNNO 1735. the steams, &c. which rested on the wax and glass. Which he thinks suffici- ently proves the steams, &c. to be non-electric; and he thinks that it as plainly appears, that they are all electrified while ascending, because the electrical fire in the down does not join with them in their passage through it; which otherwise it would do with them, or any non-electric not electrified. XXVI. Remarks on a Petrified Echinus of a singular kind. By Ja. Parsons, M.D., F.R.S. p. 155. This echinus was found on Bunnan's-Land, in the parish of Bovingdon in Hertfordshire, which is a clay, and supposed to have been brought with the chalk, dug out of a pit in the field. The round echinites are for the most part found in chalk-pits, and they are in general, when recent, the most tender in their shells; so that the chalk is the most favourable bed for them to be preserved in long enough to be petrified; whereas in other kinds of matter, these would be mouldered and destroyed before the petrification could commence; and it is very singular, that almost all those in the chalk are filled with flint, or partly chalk and partly flint, and sometimes with crystal. Now, as all flints and agates are nothing else but crystal debased by earth, and as it is in beds of chalk that these as well as multitudes of large stones are found, one would be almost induced to believe, that chalk degenerated into flint; or, in other words, that flint was pro- duced by chalk originally. And Dr. P. says he had many specimens, that seem to prove it; in some of which they seem to show the gradual change from the one to the other, not at all like a sudden apposition of chalk to flint. Other kinds of echinites, such as the echini cordati, or heart-shaped echinite, the pileati or conic, the galeati or helmet- shaped, with several other kinds, are often formed of other species of stony particles. But the present fossil, being one of the oval kind, with large papillae, is the echinometra digitata secunda rotunda vel cidaris mauri of Rumphius, which, with the other oval echinites, are very rarely found out of chalk; and it is remarkable, that whether they are filled with chalk, flint, or crystal, their shells break with a selenitical appearance, just as the lapides judaici, and all other species of echinites found in chalk-pits, do. XXVII. On Toxicodendron. By the Abbe Mazeas, F.R.S. From the French. p. 157.* The Abbe Sauvages, of the Royal Acad, of Montpellier, communicated a discovery of a plant, the juice of which adheres, without the least acrimony, to a cloth, with more force than any other known preparation. The colour is black, * The vegetables mentioned in this paper, as well as in tlie following letter by Mr. Miller, belong to the Linnean genus rkui. i VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 5Q5 and the plant, vvhicli produces it, is the toxicodendron carolinianum foliis pin- natis, floribus minimis herbaceis. Abbe M. found also a plant of the same growing in a garden at St. Germain, then only about 2 feet high. This tree is remarkable for its leaves, which are continued like wings the whole length of the twigs. He pulled off' one of the leaves, the juice of which produced a brownish colour on his ruffle, but did not change black in less than 2 or 3 hours. He examined all the plants of the same class. Near this was the toxicoden- dron triphyllum folio sinuato pubescente, T. 6ll. Hederae trifoliae Canadensi affinis planta peregrina, arbor venenata quorundam, H. R. par. 84. Arbor tri- folia venenata Virginiana folio hirsuto, Raii. hist. 1799- This plant was not yet above 3 feet high; its leaves are hairy; their pedicles, ribs, and fibres, are red; a leaf being pulled ofF, a milky juice issued from the pedicle, which being put on linen, became a finer black than the former, in less than half an hour. In this botanical garden he saw another species of toxicodendron ; this how- ever was only a shrub, and appeared to be at its full growth. It is the toxico- dendron triphyllum glabrum, T. 6l 1. Hedera trifolia Canadensis Com. q6, vitis sylvestris trifolia. Park. Theat. 1556. This plant is remarkable for having an infinite number of black points scattered on the surface of its leaves, which seemed to be a juice extravasated through the punctures of insects. A leaf being pulled off, a milky juice flowed out, which, the instant it was exposed to the sun, became the finest and deepest black he had ever seen. The Abbe thinks that if these two trees of Carolina were of their proper height, they would produce as fine a colour as this last shrub. He put the linen marked with the three black spots into a boil of soap, and it came out without the least diminution of the colour of the spots. When this linen was dried, he threw it into a strong lye of the ashes of green wood; and again it came out without the least alteration of the 3 shades of the spots, produced by the 3 plants. He took a handful of the leaves of the toxicodendron glabrum, to try if it might be of use in dying; and made a very strong decoction of it; and while boiling he dipped linen in it: it was tinged green, but, besides its not being a good green, the whole surface was unequally coloured; for several places took a fine black: whence he concluded, that the resinous juice of the internal parts of the plant was the only part capable of producing the desired effect. He was confirmed in this notion, after having let the decoction settle; it first let fall a black resinous juice in small quantity, like the opium of the shops: then a large quantity of a white sediment like a salt, which was quite tasteless on the tongue. The water appeared greenish above, and blackish towards the bottom of the vessel. He would have tried some experiments on the roots of this plant; but, as there was only one in the garden, he was afraid of injuring it. Perhaps the 4 G 2 5g6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. fruit or seeds might produce some kind of dye. Probably in making incisions in the bark, a juice might be obtained which might be turned to some use; for tlie blacks of our painted cloths, which are preparations of iron with nut-galls, after a certain number of >vashings, are quite spoiled, and only leave a rusty co- lour behind. But it is not so with the toxicodendron foliis pinnatis, since the Abbe Sauvages assures, that it was 5 years since his linen, marked with the juice of this plant, has retained the black spots, notwithstanding the great number of washings in lye it had gone through. On the Same. By Mr. Philip Miller, F.R.S. p. l6l. That the above communication of the Abbe Mazeas might not appear in the Transactions of the r. s. as a new discovery, Mr. Miller gives the following brief account of what has been written on this subject. Dr. Kaempfer, in his Fasciculus Amaenitatum exoticarum, has given a figure and description of this plant, which are so accurate, as to leave no doubt of its being the same plant as the Carolina toxicodendron. His book was printed at Lemgow, in 1712. His title of the plant is arbor vernicifera legitima, folio pinnato juglandis, fructu racemoso ciceris facie. And by the inhabitants of Japan it is called sitz vel sitz dsju, as also urus seu urus no ki. In the same book there is a figure and description of the wild varnish-tree, which he calls, arbor vernicifera spuria sylvestris angustifolia ; and the inhabitants, fasi no ki ; but the varnish which comes from this tree is of little esteem. The seeds which were sent to the b. s. some years ago, for those of the true varnish-tree, by the Jesuits at China, prove to be of this wild sort ; and the account which those fathers sent of the manner in which the varnish is procured, being so very different from that which is mentioned by Dr. Kaempfer, that he here transcribes it, as follows. They first slit the bark of the branches of the shrub, in different places, with a knife : from these wounds there flows out a white clammy juice, which soon turns black when exposed to the air : the same juice is contained in the leaves and stalks of the plant. This juice has no other tasteable quality but that of heating without turning sour, but it is dan- gerous to handle, being of a poisonous nature. When they make these incisions in the branches of the trees, they place wooden vessels under them, to receive the juice as it drops from the wounds ; and when these become dry, and will afibrd no more juice, they make fresh wounds in the stems of the shrubs, near their roots, so that all the juice is drawn out of them. They then cut down the shrubs to the ground, and from their roots new stems arise, which in 3 years is fit to tap again. This native varnish scarcely wants any preparation ; but if any dirt should happen to mix with it, the Japonese strain it through a coarse gause, to cleanse it ; then put it into wooden vessels, covering it with a little of VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 597 the oil called toi, and stretching a skin over it to prevent its evaporating. The varnish exhales a poisonous vapour, which occasions great pains in the head, and causes the lips of those who handle it to swell : on which account the arti- ficers, when they use it, are obliged to tie a handkerchief over their nose and mouth, to prevent these effects. The shrub is chiefly cultivated in the provinces of Tsi, Kocko, and Figo : and the best varnish in the world, he says, is produced about the city Jassino : but there are many other sorts of vaniish, which are collected in Siam, Corsama, and other provinces, which are much inferior in their quality to this, and are produced by different plants : but one of the best among those, he says, is pro- duced from the Anacardium, or Cashew-nut-tree. This is procured by perforat- ing the bodies of the trees, and placing a hollow tube into the hole, under which is put a wooden vessel, to receive the liquor, as it flows through the tube; and when they have obtained as much of the juice as will flow out, they stop the holes made in the trees. This juice is white when it proceeds from the wounds, but changes black when exposed to the air. This varnish is used, without any mixture, for staining black ; but the Chinese mix with it native cinnabar, or a red. kind of earth, to make a different colour. The plant, which the Abbe de Sauvages mentions, is also figured and described by Dr. Dillenius, in the Hortus Elthamensis, p. 3C)0, by the title of Toxicoden- dron (bliis alatis, f'ructu rhomboide, where he also quotes the description from Dr. Kaempfer, with the account as above mentioned ; and he has added all the synonyms from the different authors, who have mentioned the plant, and makes no doubt of its being the same with that of Japan, which, he says, should not seem strange, that a varnish-tree should be fovuid in America, near the same latitude with Japan ; since the Genseng, the Bignonia, commonly called Catalpa, with many other plants, are found to be natives of both these countries. And he questions, if the tea-tree might not be discovered in America, if persons of skill were there to search for it. And he is surprised, that the inhabitants of the English colonies in America have not attempted to procure the varnish, by which a considerable profit may arise to them, as the plant grows naturally in so great plenty there. ■ yj,>ii Ml v.t ii-iurrr Mr. Catesby, in his Natural History of Carolina, vol. i. p. 40y has given a very good figure and description of this plant : he calls it toxicodendron foliis alatis, fructu purpureo pyriformi sparso. And he says the inhabitants of Carolina and the Bahama islands call it, poison-tree, and poison-ash, as the other 2 sorts of toxicodendron are called poison-oak in Virginia and New England. Mr. Catesby takes notice, that from the trunk of these trees is distilled a liquid, black as ink, which the inhabitants say is poison ; but does not mention its being used there. There are two accounts of tlie poisonous quality of this tree, printed in 598 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. the Phil. Trans of the r. s. N" 367. The first was sent by the Hon. Paul Dud- ley, F.R.s. from New England, and the other was communicated by Dr. Wm. Sherrard, f.r.s. By both these accounts it is very plain, that this species of toxicodendron grows naturally in Virginia and New England, in as great plenty as Carolina, where all the species are the most common under-wood, in the lands which have not been cleared. He adds, that as these shrubs are so very com- mon in our northern colonies, and the anacardium, or cashew nut-tree, is also common in our southern colonies of America ; it were to be wished that the inhabitants of both would make some experiments to collect this varnish, which may not only produce much profit to themselves, but also become a national advantage. XX Fill. On the Method of Constructing a Table for the Probabilities of Life at London. By the Rev. ff'llliam Brakenridge, D.D., F.R.S. p. 167. The great Dr. Halley, who had a singular faculty of applying his mathema- tical knowledge to the purposes of life, was the first who particularly attended to this subject. In the year 1692, from the bills of mortality at Breslau, he reduced it into a sort of science ; and gave a table of the probabilities of life, that hitherto has been justly esteemed the most exact of any thing of the kind ; from which he and others have deduced many propositions, that are highly useful. But a doubt having arisen, whether that could properly, or with any accuracy, be used by us at London, as we are in a different country, and perhaps in a different way of life. Dr. B. has been at some pains to inquire into this, and satisfy himself about the objections. And he imagines that he can now show how that table may be altered, to suit our case with sufficient exactness. In the London bills of mortality, for the last 30 years, there is always added an account yearly of the number of burials under each age, at the distance of 10 years, and of children more particularly under 2 years, between 2 and 5, and between 5 and 10 ; which numbers are curious and useful. And though there may sometimes be some inaccuracies and omissions, these numbers are as exactly given as in our case can be expected : and what may be objected, is not so much to the incorrectness of them, as to what arises from our circumstances, that will not allow them to be proper to show the probabilities of life in all its periods. But if we compare the numbers of the dead, in the several periods at Breslau, with those at London, we shall plainly see that the former show the decrements of life in a natural and regular way, and free from the difficulties and objections . found in those of London. In the infant state, under 2 years of age, there is a 5th lost by death ; but afterwards, as they gather strength, the deaths are di- minished till between 10 and 20 ; and from that age the mortality gradually VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 699 increases, till after the age of 40 ; when the number of the dead continues nearly the same, though the probability of life continually decreases till the age of 80 ; and then at length, the living being almost all exhausted, the burials are greatly diminished, AU which seems to be agreeable to the course of nature ; but con trary to what we see in the London bills, especially after 50 years of age. How- ever, they both agree in thi?, that the most healthy age is between 10 and 20, and the infant state under 5 years of age the most uncertain for life. Indeed it must be acknowledged, that in computing the Breslau table. Dr. Halley had great advantages, which have made it so perfect. He had the num- ber of births given, besides the burials at the different ages, in an inland town, where there is no great concourse of strangers. But with us at London, the number of births is not known ; because of the number of Dissenters of various denominations, both foreigners and natives, of whose baptisms there is no ac- count taken ; which makes our bills at psesent very imperfect. For none are put into our bills but those wiio are baptized according to the form of our esta- blished church. And therefore there are some thousands omitted, and yet many, perhaps the one- half of them, ^vho are not baptized with us, bury with us; which greatly perplexes our bills. And under this disadvantage it appears very difficult to make an accurate computation of the decrements of life through the different ages ; though this defect he imagines he shall be able nearly to supply. floulw -')-iThere have indeed been some ingenious men who have thouight, that our London bills are correct enough to form a table from them, which may better agree with our circumstances than that which Dr. Halley has given us. And Mr. Smart was the first who endeavoured to do something in this way, from our bills only, about 18 years ago. But, in the table made by him, he seems to have been greatly mistaken ; for he has made no allowance for the accession of strangers, but considered the numbers of the dead, in all the periods of life, as all come from those born here ; whereas it is evident that the strangers, above 20 years of age, are at least equal to them. And this has brought this paradox into his table, that young people between 12 and 18, at London, are much more healthy than at Breslau, or in any country place in England. For accord- ing to him, in the 13th year, 2 die only out of 479 5 but at Breslau there die 6 out of 634; that is, there is double the number die more at Breslau than at London ; which appears impossible. But between 30 and 40, he makes them much more unhealthy than they are ; for at 40 he supposes one to die in 29 ; whereas there does not die above one in 30, all ages taken together, with infants included. Another ingenious gentleman, having seen this inconsistency, has endeavoured to correct it, by supposing that the number of strangers that come to settle in town, after 25 years of age, is inconsiderable ; and that above that age, the numbers of burials may be considered, as arising from the natural de- (JOO PHILOSOPHICAL TKANSACTIONS, [aNNO 1755. grees of mortality ; and then by proportion, increasing the numbers of the living corresponding to all ages below 25 ; so that the table, altered in this manner, is the same with Mr. Smart's above that age. And it must be con- fessed, that this correction is very proper, and worthy of its author. But still the table is greatly defective, as he has made no allowances for the recess of great numbers who, after they have been a number of years in town, leave it, if they survive ; and of many others who, after the age of 50, retire from busi- ness into the country. And which is so very obvious, that our burials are fewer than by proportion they ought to be after 50 years of age, as mentioned above, and by consequence the people appear more healthy after that age ; so that after 70 they seem more healthy than at Breslau. For at 75 there appears from this table to die 4 out of 45, whereas at Breslau there die 10 out of 88. And that a great number retire from the town, after the age of 50, or before, is further evident, if we suppose, even according to this corrected table, that one in 25 die at the age of 50. For then the number of people alive, between 40 and 50, will be greater than 2604 multiplied by 25, or 65100: which ought to be exhausted by all the deaths in the subsequent period. But all the deaths which ought to arise from that number of living, in the following years to go, according to the bills in the 3d column, is 5315 multiplied by jO, or 53150; which is less than the people that were alive between 40 and 50, by 1 1950, or rpore. And therefore above 1 1000, of those between 40 and 50, must have re- tired from town. : 1; .K' J h,.3ut now, as our bills are defective, it is next to be considered, what we at London are to do at present, and what method of computation we are to follow? And Dr. B. imagines it is very obvious what may be done. Our bills may be used so far as 14 or 20 years ; for there is certainly no increase of our people till the age of 14; because few young people come to town till they are fit to be appren- tices or servants. And between 14 and 20, though many come at that time, yet there is an emigration of a great number from hence to sea, to other coun- tries, the universities, and country academies, that nearly balances the accession of strangers. And then, after 20 years of age, the Breslau bills will be suffi- ciently correct, to show the probability of life within and about the city. And if so, a table may be made from both bills, that will agree with our case here with sufficient exactness. For he cannot find that there is any difference in the bills, above the age of 20, that can be depended on. And from all considerations, he thinks it may be allowed, till it is otherwise demonstrated, by bills formed in a different manner from what they are at pre- sent, that the probabilities of life are much the same at London as at Breslau, at the age of 20 or after 14. And if we take this for granted, we shall from thence be able to form a useful table, for those within our bills, by accommodating and ■VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 601 joining the bills of both places together. And we may also nearly determine the number of infants born here, which hitherto has not been considered. Now, from the births, which are found = I9561, and the numbers of the dead in the different periods known by our bills, it will be easy to form a table of the decrements of life ; because the dead in the intermediate years may be found by proportion from the Breslau table. And accordingly Dr. B. computed the following, which is constructed from the London and Breslau bills together; which he thinks is a surer method of computing for us at London, than from either of them alone. The first part to the 21st year, is done from our bills, and the other part from the Breslau ; but it is formed in such a manner, that it goes on as if from the bills of one place only. For, after the age of 20, it is continued by proportion, by making the dead at London in the decennial periods, to have the same ratio to each other, as the dead at Breslau. It supposes lOOO persons bom in one year, and shows the annual decrease of them by death till 87 years of age, which may be considered as the utmost period of life. The in- termediate numbers, marked d, show the dead in each year. The use of this table is well known to all who can compute the value of annuities for lives. Age. Pen. Age. Pers. Age . Pers. Age . Ptrs. Age. Pers. Age. Pers. Age. Pers. 1 Age. Pers. 1 1000 12 403 23 361 34 311 45 248 56 176 67 99 \ 78 28 323 d 4d 4d 5d 6d 6d 7d 6d 2 677 13 399 4d 24 357 4d 35 306 6d 46 242 6d 57 170 6d 68 92 79 22 127 d 6d 5d 3 550 14 395 25 353 36 300 47 236 58 164 69 86 80 17 45 d 4 d 4d 6d 6d 6d 6d 4d 4 505 15 391 26 349 37 294 48 230 59 158 70 80 81 13 32 d 4d 4d 1 5d 7d 6d 7d 4d 5 473 16 387 27 345 ! 38 289 49 223 60 142 71 73 82 9 26 d 3d 4d : 6d 7d 6d 7d 3d 6 447 17 384 28 341 39 283 50 216 61 136 72 66 83 6 13 d 4d 5d 5d 7d 6d 7 A 2d 7 434 18 380 29 336 40 278 51 209 62 130 73 59 84 4 9d 4d 5d 6d 7d 7d 7d Id 8 425 19 SIS 30 331 41 272 52 202 63 123 74 52 85 3 7d 3d 5d 6d 7d 6d 6d Id 9 419 20 373 31 326 42 266 53 195 64 1 17 75 46 86 2 6d 4d 5d 6d 7d 6d 6d Id 10 413 21 369 32 321 43 260 54 188 65 111 76 40 87 I 6d 4d 5d 6d 6d 6d 6d u 407 22 365 33 316 44 254 55 182 66 105 77 34 4d 4d 5d 6d 6d 6d 6d XXIX. Of a Sheep, shoived alive to the Royal Society, in November I754, having a Monstrous Horn growing from his Throat ; the stuffed Skin of which, with the Horn in situ, was placed in the Museum of the Society. By James Parsons, M.D., F. R. S. p. 183. This animal was bred in Devonshire, with the preternatural horn appearing at VOL. X. 4 H 602 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. its birth. The novelty of the thing made the farmer spare the life of the lamb, and bring it up till it grew to the size of a well-grown sheep, pretty large of its kind, and about 3 or 4 years old. When it was brought before the Society, the owner said the horn weighed 26 lb. ; and the creature swung it about, and raised it up with amazing strength. When he was fed, he moved forwards, letting the horn drag between his fore-legs, by which he was enabled to lay his nose to the ground ; for the skin, by which it hung, was flexible, and though reduced to a neck, with respect to the circumference of the horn, yet it was hollow as well as flexible, leaving an open passage from the flesh of the neck to the cavity of the horn, and its contents. Sometimes the horn would come into such a position, as to twist the skin, which gave the sheep great uneasiness ; but from . experience he knew how to relieve himself, and from custom became ready at that, as well as bringing it between his legs to favour his feeding. It was in length along the convex or anterior surface, '2 feet 7 inches ; and on the concave side 2 feet 1 inch ; its greatest circumference 2 feet 2 inches, middle circum- ference I foot 6 inches; and near the apex 1 foot; and its weight is now 15 lb. though emptied of its contents. It was said that on opening him there was found, in the top of the horn next the throat, which was hollow half-way down, a skull of a contracted round form, with blood-vessels running on it, and a bag filled with grumous blood, among which was a substance like a sheep's liver and lungs ; and a perfect sound kidney, like that of a fresh loin of mutton. And this was attested by the names of 3 house-keepers of credit, who were present when the animal was opened, and who, if required, were ready to make oath of it. AJTA'. ^ Dissertation on the Cancer of the Eye-lids, Nose, Great Angle of the Eye, and its neighbouring Parts, commonly called the Noli-me-tangere, deemed hitherto Incurable by both Ancients and Moderns, but now shown to be as curable as other Distempers. Addressed to the R. S. of London by Mons. Daviel, Surgeon and Oculist to the King of France, &c. Translated from the French by James Parsons, M.D., F.R.S. p. 186. The examinations M. D. had made in these kinds of tumors had informed him, that cancers of the lids, nose, and adjacent parts, have all their seat in the periosteum, and perichondrium ; and that a cure cannot be expected without taking them entirely oft": for the vessels that go from the cancerous tumor are so strongly connected with the periosteum and perichondrium, that they seem but one body, which becomes at length so greatly swelled, that the very bone is often affected. When a wen or wart (which is often the beginning of a cancer) begins to appear, and it is attempted to be pulled off", it becomes irritated, and spreads so that the edges are reversed, and become callous and livid, accompanied VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 603 with a pain, and all other symptoms which characterize the cancer. These kinds of wens, warts, and tubercles, which are situated in the great angle of the eye, or on the lids, or the nose, often shoot out their roots on the cartilages, that is, on the very membranes which cover them, and the roots sink in sometimes to the substance of the cartilage itself, which they swell and tear in the end. The more that cancers are touched with caustics, the more they are irritated; therefore there is but one method, but it is a sure one, of curing them, and hindering their progress ; which is, to take them off with a cutting instrument, destroying the periosteum and perichondrium, or even the lids, if the cancer has penetrated them in their substance, with their cartilages : which the follow- ing observations will prove : Observ. 1. — On a cancerous upper-lid. August 11, 1736, M. Daviel was called to Madame de la Fague, a nun, at Bourdeaux, 45 years old ; for a tumor on the upper lid of the right eye, which she had for 20 years : it began by a small wen, and increased by degrees, so as very much to incommode her. She applied to a surgeon, who began by applying some drops of a liquid caustic, which enraged the tumor still more ; which he appeased again by anodyne me- dicines ; and then the tumor remained a long time without any sensible increase; though she felt a continual sharp pain in it. But, as even the least disorders are impatiently borne, she was willing to be relieved, and consulted another surgeon, who took off the tumor with a cutting instrument, and who, seeing that the ulcer, which was the result of the operation, did not heal, but on the contrary made great progress in its erosion, and became callous, he touched it with lapis infemalis ; and sometimes with a liquid caustic : which so much the more increased the evil, and made her resolve to suffer no more applications, because all that had been tried made her worse and worse. She was now a long time in this state, when M. D. was called to consult with several other practi- tioners, who, having examined the case, agreed with him that there was no other method to be taken but the operation, not only to save the eye, but to prevent an incurable cancer, which threatened her life. Therefore he proposed the total extirpation of the lid : which proposal being approved of by all, as the only me- thod of saving the eye, the operation was performed in the following manner : He passed a crooked needle, with a waxed thread, under the lid, by which he suspended and drew up the lid and tumor, which he cut oft' with the crooked scissars, as much as he could under the orbit, separating the whole to the divi- sion of the lids; a small haemorrhage ensued, but which was soon stopped with dry lint, and a dry compress and bandage. She remained 24 hours without being dressed ; was bled twice in the arm, after the operation : he then dressed her up with light dossils, armed with the 4 h2 ()04 VHILOSOPHICAL TRANSACTIONS. [aNNO 1735. linimentum Arcaei, and she had not the least accident from the day of the opera- tion to the 25th of the same month, when she was perfectly cured, without any deformity in her eye : and though the lid was cut away very high, the eye re- mained very neat and well, performing its several functions properly when he left Bounleaux; and the 13th of August 1742, having had an opportunity of taking a journey to that town, he saw the patient again, whom he found ex- tremely well, seeing perfectly with that eye : but what he found very singular was, that the skm of the lid descended pretty low, to the cornea, which it al- most covered ; so that the whole globe was in a manner hid. He onlv observed that this resembleii a lid without hairs. Observ. 1. — On another cancerous tumor in the great angle of the eye. July 2, 1736, Margaret Combaucaut, of Carcastone in Languedoc, 60 years old, had a cancerous tumour, for 16 years, in the great angle of the right eye: it began by a little wart, which itched violently, and made her scratch it very often, which so irritated the tumor, that in a little time it became as large as a dried fig flatted, with its edges turned outward and callous. It reached from the commissure of the lower lid, an inch and half below it, even to the right ala of the nose, which proved extremely troublesome to her. He found, after a strict examination, that it adhered to the bone. She said she tried all the remedies that she imagined would do her any good ; but that, far from relieving her, they rather made her worse, and her disease became the moi-e insupportable , and that she had taken a resolution to undergo any thing to be freed from a disorder which had afflicted her for 1 6 years. Having consulted Mr. Fabre, an able physician of that place, they were both of opinion, that she could not be cured without an operation, which he accord- ingly proceeded to as follows : he took off" the tumor entirely to the periosteum, but did not lay the bone bare ; for he thought it sufficient for a complete cure to take away all the callosities; but he was mistaken ; for instead of the prospect of a succeeding cure, he was unhappy enough to see the swelling increase, and the wound seem larger than before. He used in vain all the remedies commonly thought of in such cases ; he scarified the edges of the ulcer, to bring it to sup- puration ; but it became more hard and callous than before the operation, and much more painful. He therefore resolved to cut away all that remained of the tumor, with the periosteum, which appeared very much swelled. This second operation had so much success, that the swelling, and every other bad symptom, disappeared almost suddenly; and in 3 days the wound looked red and very well, without any pain, and the cicatrix was perfectly formed on the 15 th day from the operation, without any sensible exfoliation of the bone, or the least deformity or staring of the eye. She had remained very well ever after ; for he saw her the 10th of August 1741, at Carcastone, in perfect health ; and the cicatrix of the VOL. XLIX.3 PHILOSOPHICAL TRANSACTIONS. 605 part very even. He observes, that he laid the entire bone bare, wherever the tumour touched, even down to the ala of the nose of that side. Observ. the 3d was on a cancerous tumor of the same nature, and in the same situation, and the treatment just the same ; it was as large as a filbert, and the officer was afflicted with it 20 years. It differed from the former only in this, that the year before the officer came to Marseilles, to put himself under Mons. Daviel's cure, the tumor broke, and discharged a very fetid acrimonious matter, which, running into the eye, brought on a troublesome ophthalmia, and the edges were livid, and had a very terrible aspect. As to his operation, it consisted, as before, of a total extirpation of the cancer, periosteum and all, to the bare bone. He dressed the bone with dry lint only, and his digestive was a mixture of the linimentum Arcaei, with the unguentum styracis : and in about 1 9 days he was so perfectly cured, that when he returned to his friends, several of them asked him, on which eye the operation had been made ? Observ. 4, differed in nothing from the former. '1 Observ. 5, On a cancerous tumour on the nose, which reached from the root of the nose down to the middle of the cartilage. He treated it in the same manner, taking off the whole with the periosteum ; and, as it was partly upon the cartilage, he also cut away the perichondrium, laying that, as well as the bone, bare : and the cure was completed, without leaving any deformity behind, in 18 days. Observ. 6. Of a cancerous tumor on the great angle of the right eye of a woman at Marseilles, of 70 years old. This he treated exactly in the same manner, and she was cured in 20 days. The 7 th observation mentioned another cancerous tumor on the nose, and its cartilage, of a gentleman, which was circumstantially the same with the former : it was cured in 5 days. After this case he makes this conclusion : that from all that has been already said, it is plain, that the seat of the cancers of the eye lids, nose, and other neighbouring parts, is absolutely in the periosteum and peri- chondrium, as well as the fat ; and that there can be no hopes of a cure without taking off these membranes, with the fat, and even any parts of the very carti- lages that may be contaminated : but that in this manner they are as curable as cancers on other parts of the body, notwithstanding what all oculists have said to the contrary. The 8th observation was on a cancer on the lower eye-lid of a woman, cured in the same manner. The gth observation treats on a cancer,as large as a large filbert, in the angle, and on the lower lid of the eye of a gentleman; which began by a small tu- bercle in the angle, and was pulled off, and grew again several times. Mons. Daviel was consulted, in the presence of another surgeon, Mons. Maillot, and 60fi THILOSOPHICAL TRANSACTIONS. [aNNO 1755. declared for taking the tumor and eye-lid entirely off; making this prognostic, that if any part was left behind, the eye would be deformed and staring ; but the other surgeon thought, that half the lid with the tumor would be sufficient for the cure: Mons. Daviel therefore only cut away half the lid with the tumor ; with which he also took off a large quantity of hard white fat, and dressed up the part as usual ; but in the progress the lid was turned outward, and then they resolved on the total extirpation of the lid ; which, being obliged to depart from thence, he left to Mons. Maillot, who performed it with such success, that his cure was complete in 15 days, without the least deforniity whatever. . The 10th Observation is a case of the same nature with the former, with this difference, that when he had taken off the tumor and under lid in the same manner as usual ; the patient continued getting well till the Qth day from the operation ; when Mons. Daviel perceived a small fungus in the middle of the tumor, which he touched with the lapis infernalis, which produced very ill effects: the eye grew painful, the conjunctive swelled very much, the wound, which was half healed up, opened afresh, and became ragged. This made him set about cutting away all the bad flesh he could perceive, with the inequalities of the conjunctive, which was much swelled : he scarified the cornea, and in the inner surface of the upper lid, which was also greatly tumefied, and even opened it on tlie upper surface. Thus, after having emptied the vessels well, he fomented the whole with a decoction of marshmallows, mullein, violet- leaves, camomile-flowers, melilot, leaves and flowers of rosemary, thyme, lavender, rue, and marjoram, of each half a handful, in a sufficient quantity of water; to a quart of which he put a bit of camphor the size of a nut. The frequent application of this that day produced so good an effect, that all her pain ceased : he also bled her in the arm and foot, ordering emollient clysters. She was purged some days after, with manna and cassia, which did very well ; and she was perfectly cured, without the least deformity, and could see better than before the operation. XXXI. Of Four Roman Inscriptions, cut on Three Large Stones. By John Ward, LL.D., F.P.R.S. p. 196. The stones were found in a field near a mile from Wroxeter, formerly a Roman station called Uriconium,* in the months of September and October 1752. The first of them was discovered by a plough striking against it ; and by spitting the ground the other two were discovered, not far from the first, in the like situ- ation. The first and last lay separate from their bases, which being taken up, • In the year 1701, a Roman sudatory was discovered at this place, a draught of which, with some account of it, was published in the Phil. Trans. N" 306, which seems to have escaped the observa- tion ol Horsley, Brit. Rom. p. 419. — Orig. r VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 607 several broken pieces of urns, and dust of a greyish colour, ^were found with them, which seemed to have the appearance of ashes. N^ 1, is by the scale 6 feet 8 inches high, and about 2 feet 3 inches wide above the base. It has a pediment top, with a pine apple rising from the middle of the cornice, on each side of which is a lion, and in the area of the pediment a kind of rose. The inscription, which is cut in the plane of the stone, may be thus read; Caius Mannius, Caii filius, Pollia tribu, Secundus PoUentinus, miles legionis vicesimae, annorum lii, stipendiorum xxxi, beneficiarius legati prin- cipalis, hie situs est. N" 2 contains two inscriptions, and is in height 2 feet 7-i- inches, by 2 feet 4-f- inches in breadth. It is not flat, as the former, but gently convex crosswise, the lower part being divided into 3 pannels; on the first two of which are the in- scriptions, but the other seems never to have had any on it. The upper part is ornamented with a pediment, in the area of which are the remains of a face with curled locks, and 2 snakes under it; and on the cornice 2 figures like dolphins. The first inscription may be read thus: Diis Manibus. Placida annorum lv, curam agente conjuge annorum xxx. And the other in this manner: Diis Ma- nibus. Deuccus annorum xv, curam agente patre. N° 3 is 6 feet 1 1 inches high, and about 2 feet broad above the base. It has also a pediment at the top, the area of which is filled with a large flower. The inscription, it exhibits, may be read in the following manner; Marcus Petronius, Lucii filius, Menenia tribu, vixit annos xxxviii, miles legionis xiiii geminae, militavit annos xviii, signifer fuit, hie sepultus est. XXXI 1. On an American Wasp's West,* shoivn to the Royal Society. By Mr. Israel Mauduit, F. R. S. p. 205. M. de Reaumur distinguishes wasps into three classes, from the difl^erent situa- tions in which they place their nests; some choosing unfrequented parts of houses, some little cavities in the earth, and others the branches of trees for that purpose. The first of these is the largest sort, or hornet ; the second is the common sort herein England; and the last is more frequent in America. The nest, then shown to the Society, was sent from Maryland, where they are found on the lower kinds of trees, in the thickest parts of the woods. This was built on a dogwood-tree, or the comus mas Virginiana; and hung quite de- tached from the rest of the tree by an extreme branch, of little more than an inch circumference: which, with its smaller divisions running through the substance of the nest, answered the purpose of pillars, to unite and support the several floors • This wasp's nest, which is not described with sufficient accuracy, is probably that of the vespa nidulans of Fabricius. 608 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. of the fabric. The figure was a conoid, or an acuminated oval; its longer dia- meter 20 inches, the shorter near the base 12. It was perforated on 2 opposite sides, for the wasps to enter and go out at. The shell was composed of paper; the sheets of which at its upper end were larger and more distinct. They were of an ash-colour, of different shades, and streaked or marbled, and, being lightly laid on each other, formed a wall of from 1-J^ to 4 inches thickness in the several parts of it. The lax hollow manner, in which they were joined to each other, ren- dered them a more effectual security from rain; as they attracted water in com- mon with all other substances, made of the same materials; and would have been more easily soaked through, if they had been closer compressed together. For the same reason the apex of the cone was of the greatest thickness, and the base of a stiffer and more cellulose texture. This substance appeared to be a true paper; but, by the exact economy of nature, wrought to that degree of perfec- tion only, which was necessary to serve the single purpose it was intended for. Being examined by the microscope, it appeared to be of a coarser grain, a shorter staple, and of a much looser texture; and was a rare, though not a singular in- stance, of a natural production falling far short of the artificial one of the same kind. The inside structure of these nests, is well described by M. de Reaumur. XXXIII. Abstract of a Letter from the Magistrates of the City of Mascali, in Sicily, concerning a late Eruption of Mount Etna. From the Italian, p. 209. On Sunday, March 9, 1755, about noon, mount Etna began to emit a great quantity of flame and smoke, with a most horrible noise. At 4 o'clock the air became totally dark, and covered with black clouds ; and at 6 a shower of stones, each of which weighed about 3 oz. began to fall, not only all over the city of Mascali, and its territory, but all over the neighbourhood. This shower con- tinued till a quarter after 7, that by the darkness of the air, the fall of stones, and the horrible eructations of the mountain, the day of judgment seemed to some to be at hand. After the stones had ceased falling, there succeeded a shower of black sand, which continued all the remainder of the night. The next morning, at 8 o'clock there sprung from the bottom of the mountain, as it were, a river of hot water, which in the space of half a quarter of an hour, not only overflowed to a considerable distance the rugged land, near the foot of the hill, but, on the waters suddenly going off, levelled all the roughness and ine- qualities of the surface, and made the whole a large plain of sand. The stones and sand, which remain where-ever the inundation of the water reached, differ in nothing from the stones and the sand of the sea, and have even the same saltness. After the water had ceased flowing, there sprung from the same open- ing 9. small stream of fire, which lasted for 24 hours. On Tuesday, about a mile below this opening, there arose another stream of fire, in breadth about VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 60Q 400 feet, like a river, which overflowed the adjoining fields, and actually con- tinues with the same course, having extended itself about 2 miles, and seeming to threaten the neiglibourhood. XXXir. Of the Ckarr Fish in North Wales. By the Rev. Mr. Farringlon, cf Dinas, near Caernarvon, p. 210. This species they call torgoch, or red belly. This redness in the female, paler or deef)er according to the season, resembles that of the fins of a roach, a fish very common in many rivers of England, though we have none of them in this country. The male is not adorned with that beautiful hue, yet he is finely shaded, and marbled on the back and sides with black streaks, on a kind of pel- lucid light sky-coloured ground. The shape is like a trout, but much more elegant and delicate. Three lakes or large pools, at the foot of Snowden, afford being and subsistence to this remarkable finny race. There is a communication between them. About a fortnight in December the charrs make their appear- ance; never wandering far from the verge of these lakes, or the mouths of the rivers issuing from them ; but traverse from one end to the other, and from shore to shore indifferently, or perchance as the wind sits, in great bodies; so that it is a common thing to take in one net, 20 or 30 dozen in a night, at this place; though not above 10 or a dozen fish in all at any other. Thus in winter frosts and rigours, they sport and play near the margins of the flood, and probably de- posit their spawn ; but in the summer heats they keep to the deep and centre of the water, abounding in mud and large stones, as the shoaler parts do with gravel. After Christmas they are seen no more till the following year. XXXV. A Method proposed to restore the Hearing, when injured by an Ob- struction of the luba Eustachiana. By Mr. J. fVathen, Surgeon, p. 213. Whatever obstructs that passage leading from the ear into the nose, called tuba eustachiana, so as to hinder the ingress of the air through it into the cavity of the tympanum, is universally deemed destructive to the sense of hearing. Hippocrates observed, that in a quinsy of the fauces, the patient became deaf, by its compressing and closing up this tube.* Many practical writers assert the same to have happened from adjacent ulcers, &c.;-^ and Mr. W. had known a swelled tonsil occasion deafness. This canal opens into the lateral and anterior • Coac. 1 1 . n. 35. t Haller in Boerhav. de audita, p. 380, and 4l6. Tulpius 1. n. 35, a tumore palati. Valsalva, cap. V, p. go, a polypo. et ulcere (viz. a certain yeoman had an ulcer above the uvula, on the left side, which communicated with, and corroded part of, the orifice of the left tuba eustachiana; which, when he stopped with a tent dipped in medicine, he immediately lost bis bearing in that ear, but recovered it as soon as the tent was taken out). — Orig. VOL. X. 4 I 6lO . PHILOSOPHICAL TRANSACTIONS. [anNO 1755. part of the cavity of the tympanum ; is so shaped that it first decreases, as it descends towards the posterior parts of the nose, becoming very narrow; then suddenly diverging, is much enlarged, opening into the posterior part of the nose by an elliptic orifice, a little prominent, turning inwards and forward, placed laterally, and just above the velum pendulum palati. This canal then is com- posed of two distinct cones, the extremities of which unite together, but their bases diverge differently; it is likewise lined with a porous membrane, full of cryptae and mucous cells, continued from and like to the membrane of the nares.* When therefore we consider the structure of the eustachian tube, and its free communication with the atmosphere, we may reasonably suppose it subject to inflammation of its membrane, and concretion of its mucus, from cold, &c. like the external meatus ; and though its mucus is of a very different nature, it is nevertheless liable to inspissate by heat, when its thinner parts are exhaled.-^ And from the form cf this passage we may easily conceive, that an obstruction, pretty far advanced, is not to be removed without difficulty, and that in propor- tion, as it is more or less complete, the hearing will be more or less injured. Why then may not this be suspected as sometimes the cause of deafness? per- haps it is not unfrequently so; e. g. When a patient is somewhat deaf from cold, and the outer ear has been examined, and found clear of hardened wax, &c. it is yet not uncommon to find himself suddenly relieved by a great noise in his ear. This is probably owing to the breaking away of the congealed mucus, and the instantaneous rushing of the air into the tympanum ; so that when this dis- order is but slight and recent, nature seems frequently to relieve herself; but when more confirmed, her efibrts are ineffectual for its removal. These consi- derations inclined him strongly to think the hearing might suffer from that cause, and he was much confirmed in it by the following very remarkable case. Richard Evans, aged 35, was very deaf in both his ears, yet no visible disorder in the external meatus. It arose from cold, and had subsisted several years, during which time no art or means could procure him the least relief. In August, 1/55, he died of the small-pox, at the hospital in Cold-bath-fields. Mr. W. took that opportunity to examine the eustachian tube of each ear, and found them both stuffed quite full of congealed mucus. This was the only visi- ble cause of his deafness, the other parts appearing in their natural state. As * Haller in Boerh. de Auditu, p. 378. Not. e Physiologia. Haller. de Audita, § 485. Valsalva, cap. 2, p. 32. idem fig. xiv.— Orig. + Morganni and others tell us, that they constantly find the cavity of the tympanum in infants always much clogged with mucus ; and Mr. Douglas has often observed the same in adults, and is of opinion that it is concomitant with an obstructed tube in general, and that the injection is equally as effectual as if the tube only was obstructed.— Orig. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 6ll all these concurring circumstances strengthened him in his opinion, they likewise incited him to make trial of an operation that was some time before proposed to the Academy of Sciences, by Mons. Guyot; but the author having never prac- tised it, he wanted the recommendation of facts to support and enforce it ; it was therefore rejected by them as impracticable.* Mr. W. first introduced his probe, a little bent at the end, through the nose into the tubes of several dead subjects; and, having thereby acquired a facility, he did the same on a person that was very deaf, and on whom all other means had proved ineffectual ; no sooner had he withdrawn the probe, than he said, he could hear much better. This success excited his further endeavours, so that he had pipes of different sizes adapted to a syringe, and he had since injected the meatus intemus in the following manner, with success. The pipe is made of silver, about the size and length of a common probe, and a little bent at the end: this being fixed to an ivory syringe, full of liquor (viz. a little mel rosarum in warm water), is introduced between the ala and septum of the nose, with its convexity towards the upper part of the aperture of the nares, and thus conti- nued backwards, and a little downwards, till it comes near the elliptic orifice; then its convexity is turned toward the septum, by which the inflected extremity enters the tuba eustachiana with ease; the liquor is then impelled through it into the tube, by which the sordes, if any, being diluted, is washed out, and regur- gitates through the nose, or mouth, or both, with the injection ; and, if the quantity be large, may be seen. [Then follows an account of 6 different cases, in which the operation was successfully performed.] After the detail of these cases Mr. W. remarks, that he had endeavoured to ascertain the symptoms that indicate an obstructed tube, but had not been able to do it with any degree of certainty; nor could he see the great utility of it, could^ it be done; for the only disorders of the ear, that at present admit of surgical helps, are those of the external meatus, ulcerated and swelled tonsils, &c. all of which are generally visible ; and when they are not the cause of deafness, little or nothing is ever attempted, the patient being left to shift for himself. But now another probable chance at least is given to the unhappy sufferer, and being the only one (e. g. the others either improper, or tried before without success), • Hist, de I'Acad. 1724, p. 53. Besides, Mons. Guyot proposed doing it by the mouth, which ii quite impossible, as evidently appears to any one that will give himself the trouble to examine into it. Convinced of this, Mons. Petit (who has lately published a new edition of Palfin's anatomy) pro- posed, and that learned and skilful anatomist Mr. John Douglas first demonstrated the possibility of, passing the probe, &c. through the nose into the eustachian tubej and this he has constantly shown to those who have attended his public lectures; and to him Mr. W. freely acknowledged himself in-i debted for tlio hint, by which he was incited to make trial on the living, of an operation of so much importance to mankind. — Orig. 4i 2 6l2 PHILOSOPHICAL TRANSACTIONS. [aNNO l/So. may be made use of without delay, or attendance to accompanying symptoms, at least till they render themselves more conspicuous and certain than he had hitherto been able to find them ; and as the operation is not at all dangerous, it neither has, nor will, he believed be thought painful by those who desire to recover their hearing. XXXVI. A Chemical Essay on the Action of Quicklime on the Volatile Alka- line Salt. By I. A. Schlosser, M. D. of Utrecht, p. 222. As the true nature of quicklime was unknown at the date (1755*) of this essay, the theory which Dr. S. has offered concerning the different phenomena produced by the action of burnt lime on the volatile alkali, is wholly erroneous. It is therefore deemed unnecessary to be more particular in the notice of this paper. XXXVII. An Account of a very remarkable Case of a Boy, who, nottoith- standing that a considerable Part of his Intestines was forced out by the Fall of a Cart upon him, and afterwards cut off, recovered, and continued well. By Mr. John Needham. p. 238. On the 3d of January 1755, Mr. N. was called to the son of Lancelot Watts (a day-labourer, living at Brunsted) a servant boy to Mr. Pile, a farmer at West- wick, near North-Walsham, Norfolk, aged 13 years. He was overturned in a cart, and thrown flat on his face, with the round, or edge of one side of the cart, bottom upwards, whelmed across his loins, the upper part of the body lying beyond the wheel at right angles. In this helpless condition he continued some time, and was found with a very large portion of the intestines forced out at the anus, with part of the mesentery, and some loose pieces of fat, which Mr. N. took to be part of the omentum, hanging down below the hams, double, like the reins of a bridle, very much distended and inflamed. He had a conti- nual nausea, and violent retchings to vomit, and threw up every thing he took. The pain of the stomach and bowels was exquisite, attended with convulsions; his pulse low and quick; and frequently he fell into cold sweats. After using an emollient and spirituous fomentation, Mr. N. reduced the parts, though to no purpose; the vomiting immediately returned, and forced them out again. Next day the fever increased, the nausea and retchings to vomit continued, the parts appeared livid and black, with all the signs of a mortification. On the 3d day the mortification increasing, he cut off the intestine, with the mesentery, close • It was about a year after the above date that Dr. Black's experiments on quick-lime, which de- monstrated so cleariy the difference between mild and caustic calcareous earth, mild and caustic alkalis, &c. and which laid open so vast a field of discovery in gaseous chemistry, were first commu- nicated to the world. VOL. XLIX.J PHILOSOPHICAL TRANSACTIONS. 6l3 to the anus, being 57 inches in length. He had had no stool from the time of the accident, but soon after the operation there was a very large discharge of blackish and extremely offensive faeces, which continued several days, lessening by degrees. He soon became easy, and the nausea and vomiting abated. Mr. N. gave him tinct. cort. Peruv. simpl. twice a day; and, as he complained at times of griping pains, he took now and then tinct. rhabarb. vinos, and had re- covered a good state of health. For some time he had 6 or T , or more stools in a day; afterwards commonly 3 or 4, all loose, which come soon after eating; and frequently he was obliged to hurry out to ease himself, during his meals. Mr. N. 3 times tried to discover a passage through the coats of the rectum, with his finger, aiitl he thought he always felt an opening, just above the sphincter, towards the spine; the circumference of which was full, and protuberated, seem- ingly as large as his finger, the lower edge of which was harder than the rest; the patient complained of pain, when the upper part was pressed. On the 7th of May the boy walked from Brunsted to North-Walsham, 7 miles, was jierfectly well, and walked back again that afternoon. XXXVIII. Experiments on the Sensibility and Irritability of the several Parts of Animals. By Richard Brocklesby, M. D., F. R. S. p. 240. After apologizing for the cruelty exercised in these experiments, which Dr. B. made for the purpose of ascertaining the validity of Haller's doctrine, respecting the irritability of animal fibres, Dr. B. proceeds to state, that his first experiment was made by cutting 4 inches of a young lamb's skin, which covered the great tendon of the hinder leg, known to anatomists by the name of the tendo achillis. This of course caused violent struggles, and other marks of the injury felt; and on touching the extremity of the skin, while united to other parts of the animal, it cried loud, urined, and voided its excrement, when he poured diluted spirit of vitriol on the edges of the skin that were fixed to the contiguous parts; but did not express much pain by irritating the raised skin, at the farthest extremity of its separation, by an infusion of diluted spirit of vitriol. Nearer however to the fixed parts underneath, the sensation in the raised part of the skin continued much longer. He then made the butcher cut into the tendon half way, and divide it upwards more than 2 inches, and attentively stood over the animal, to watch his motions, and discover if there was any apparent pain ; but while that was doing, he could discern none, nor any marks of sensation in the animal, while he handled and pulled the cut tendon, nor yet any on touching it with dulcified spirit of nitre, and sharp acid spirit of vitriol; and what yet surprised him more, was to find the creature as insensible on the tendon, as if it was a mere piece of glue, when he put a strong muria of sea-salt and nitre all over it; and after a very few mi- 6l4 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. nutes he laid the raised part of" the tendon in its natural direction, on the cor- respondent fixed part, and they were both exactly congruous; so that the loose part had not contracted itself, nor was at all shorter, after these repeated trials, than its correspondent fixed part. He then put the creature on its legs, to see whether it had suffered so much, that it could not use the leg; but it was found to walk, though favouring greatly that side where so much had been done ; how- ever, it walked fairly on all its legs. After about 5 minutes tonnent, the but- cher ended all its pains, and he performed the same processes on a sheep just destined to be slaughtered, in which the Dr. found all the appearances as above- mentioned. He was induced to make 2 other very cruel experiments on different animals, by laying bare their patella's of the knees; having cut off' all the skin round about, he then pricked and touched with the afore-mentioned escharotics the capsular ligaments of these joints, without discovering any tokens of pain ; but as soon as the sharp fluids had spread over the surface, so as to reach the extre- mity of the skin, the creature underwent as much pain as cutting before had caused. He desired the butcher to take off as much skin from the forehead, as was necessary to perform the operation of the trepan; and before he began to apply the instrument to the sheep's forehead, he vellicated the pericranium with the end of a knife, but could not observe the membrane sensible, or thrown into contractions; and when the operation was over, and the bone taken from the subjacent dura mater, he poured on this membrane dulcified spirit of nitre, and diluted spirit of vitriol, and powdered common salt, but without perceiving any agitations whatever, brought on by these substances acting on these living parts ; though in some creatures he was dubious, whether sea-salt and nitre in powder did not create some sense, though no manifest contractions of the dura mater. But every muscular part, which he cut while the animals were alive, discovered little sensibility of pain, though great propensity to irregular spasms of the fibres : and the muscles on the thorax, and especially the carneae columnae of the heart, retained irritability last of all other muscular parts, even till long after the animal's expiration. He laid the pungent liquors and salts, as above, on various parts of the animal, yet alive; as on the fat, cellular membrane of the neck, leg, and other parts within the skin, the liver, pancreas and spleen, and could not find them endowed either with remarkable sensibility or irritability; nor had the bladder any remark- able symptoms of irritability, further than might be occasioned by its muscular fibres; though the well-known symptoms of the calculus show its great sen- sibility. ^ He tried the effects of a strong aqueous solution of opium on the irritated VOL. Xr.IX.J PHILOSOPHICAL TRANSACTIONS. 6l5 parts of muscular fibres, but could not perceive an opiate manifestly to compose these spastic motions of the parts, as Haller alleges they do, though in some trials he fancied there were grounds for such a conclusion. However this is no argument against the internal use of opiates, where the solids are greatly irritated. He adds one more experiment, made on the intestines of a lamb: after he had taken them from the carcase, he poured diluted spirit of vitriol on them, as well as several other pungent substances; and on the touch of all of them, the intes- tines renewed their contraction, which before had totally ceased, and surprised him with a motion almost as strong as is found in the process of chylification ; and this continued till the external cold had indurated and stiffened the fatty membrane of the omentum. These were some of many experiments of a like nature, which the importance of these facts in daily practice of medicine required to ascertain, or reject ; and, from the result of his repeated trials, he was induced to coincide with most of the conclusions drawn by Drs. Haller, Castell, and Zimmerman; that no part is sensible but the nerves only, and that some parts are irritable without sensibility, accompanying them in any great degree; while others are altogether without sense, at the same time that they are incapable of being irritated at all. Dr. B. adds, that he had thus communicated to the Royal Society the result of his experiments on this subject. Whether he should, by prosecuting the subject still farther, be able fairly to make out, that irritability, as it is distin- guished from sensibility, depends on a series of nerves different from such as serve either for voluntary motion and sensation, he could not then say. But whatever might be his future conclusions, he would establish nothing hypothe- tical, but endeavour by fair deductions to approach towards truth, as near as the abstruse nature of the subject would permit; and as he thought he had actuaHy found some variation from the common practice in rheumatisms, built on the established fact of great irritability in the muscular fibres, succeed, to the relief of suffering patients, he could not dismiss this subject, without relating, that only with gentle and continued frictions on the pained rheumatic parts with com- mon sallad oil, 2 poor patients, who lately applied for his advice in obstinate rheumatisms, were, by thus relaxing the crispation of the solids, surprisingly relieved, without any further medicine. So that after bleeding, where it is indi- cated, which above all things he found to abate irritability, it might deserve to be tried, how far animal oils, applied by friction long continued to the aggrieved parts, both in the gout, rheumatism, and other painful diseases, would ease the tortures, without repelling or obstructing the matter, which nature is labouring to throw off. But he forbore to enlarge, as the experiments he had hitherto made on the subject of irritability, were scarcely sufficient to obtain what Lord Bacon calls the vindemiatio prima in this science. When he should receive suf- d\6 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. ficient information to be convinced within himself, he should not be wanting to communicate what might tend to advance this branch of natural knowledge, and to promote a true theory of diseases, on which all rational practice must be established. XXXIX. Of Worms in Jnimnl Bodies. By Frank NichoUs, M. D. Med. Reg. and F. R. S. p. 246. Fish are, to appearance, more subject to worms* than other animals; the cod often shows small slender worms, coiled up like snakes, on the surface of its liver; and the bley in the Thames, about the month of July, is often distressed by a long flat worm, which, by possessing and eating its liver, prevents the fish from compressing itself to that specific gravity, which is necessary for its quiet continuance under the water; so that it is obliged to skip about on the surface of the water, till it becomes a prey to its foes, or dies suffocated, by being so often out of water, and deprived of that action of the water which is analogous to the force of the air to us in breathing. Among the many cases, which Dr. N. had seen, two seem to deserve parti- cular attention, as well because they are greatly prejudicial to the farmej, as be- cause, when generally known, they may possibly lead to a method of successful cure. The first of these is a species of dropsy, incident to bullocks and sheep. On opening these animals, when dead of this rot, the liver is always found affected. A small fiat worm,-|- resembling a sole, and often many of them, is found in the gall-duct, by the butchers termed fiooks [flukes]. It is the property of this worm, that it always builds a wall of stone for its defence; which wall is ramified like the gall-duct, within which it is formed. This stony tube, when completed, blocks up the gall-duct, and stops the passage of the gall ; which thereby sur- charging the duct, and dilating the orifice of the lymphatics, returns again into the blood, and gives the yellow teint to the eyes, which is the first symptom of this disease, and generally precedes the loss of flesh, and the swelling of the belly. It seems probable, that whatever can increase the acrimony of the bile, must be useful in preventing this disease; but when the stony pipe is formed, no method seems capable of promoting its discharge, or dissolution. The other case is termed the husk, and is a disease to which bullocks are very subject, while young; for it rarely afTects those of more than a year old. The creature is seized with a short dry cough, by which it is perpetually teized ; in consequence of which he wastes in flesh, and grows weaker and weaker till he dies. On opening the lungs of a calf dead of this distemper, he found the wind- * The worm here alluded to, is the ligula abdomiiialis. Linn. Goiel. + This worm is thefoiciola hepatica. Linn. VOL. XLIX.] PHILOSOPHICAL TBANSACTIONS. 6l7 pipe, and its branches, loaded with small taper worms* of about 2 inches long, which were crawling about, though the animal had been dead many hours ; and the farmer assured him that they always found these worms in this distemper, and knew of no method of cure. Dr. N. had great hopes however, that fumi- gations, either with mercurials, as cinnabar, or with fetids, as tobacco, properly used, might prove of great service. XL. On some Remarkable Insects of the Polype Kind, found in the Water ; near Brussels in Flanders. By T. Brady, M.D. p. 248. The draught of the plant sent is found in summer-time, in all sorts of ditch or stagnant waters : its colour is white, and its transparent body, when seen with the naked eye, is in length between one and a half and two lines ; but when viewed with a good microscope, whose focus is about 8 lines, it appears as in pi. 15, tig. 1, with leaves,-^- branches, and fruit, and indued with such sensibility that at the least noise made in the room, or on any thing touching the table where the microscope stands, or the water in which it lies, it contracts itself with such activity and swiftness that the eye cannot follow it in that motion, till it reduces itself into the shape in fig. 2. The extension or dilation goes slower, and requires about half a minute before it comes to the form in fig. 5. It can live in its own standing-water for 8 or 10 days, and then looks as in fig. 6, as most trees do in winter-time. It is remarkable that the leaves, which are like bells, live some time after they fall, and retain that faculty of contraction and dilatation ; and when viewed with the great magnifier, whose focus is about 2 lines, it appears as in fig. 4. The trunk is as in fig. 3. The number of its branches are undetermined, but commonly found to be between Q and 1 2. He had not tried if it did not regenerate, when cut like polypes : but he could see a vast difference between it and the polype a bouquet, mentioned by Trem- bley.;}: The other curious insect, represented in fig. 7, is found in the same standing-waters with the plant, and is seen with the naked eye, like a little fiat round leaf, whose diameter is about one line and a half ; but when put in a microscope, it shows a circle surrounded with crowned heads, tied by small thin tails to a common centre, whence they advance towards the circumference, where they turn like a wheel, with a great deal of vivacity and swiftness, till they cause a kind of a vortex, in which are seen all smaller insects or bodies either attracted or driven, which probably serve as nourishment for those little crowned things, which in all appearance are, as well as the plant, a sort of insects of prey, that live on smaller creatures. When one of those little heads * These worms belong probably to the species of ascaris called ascaris vituli. Linn. Gu el. + Vorticella anasiatica. Linn. t Vorticella socialis. Linn. Gmel, VOL. X. 4 K 6l8 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. has wheeled a while, it rests, and another turns out ; and sometimes 3 or 4 are seen wheeling at a time. He had seen last year some much more regular, that formed an orderly circle, with their crowns to the circumference, and their thin bodies like so many radii joined to the centre. Their motion is all straight towards the edge of the circle, and never to the right and left, as if every head had its proper limits to act on. The fruit of the plant, which resembles an orange, has a kind of chain about it, that turns as the crown does in the other insect. The trunk or stock of the plant is its gut, or stomach ; for he saw, that something descended through it, as it were through a gut. Besides it has no support of any fixed point, but is always swimming in the ditch-water, but shows no great local motion. Other insects were seen preying on it, which resemble small hogs, and are very busy in eating its leaves, which are probably the cause of its looking so bleak and withered when dead. XLI. New Astronomical and Physical Observations made in Asia ; and commu- nicated by Mr. Porter, Ambassador at Constantinople, and F.R.S. p. 251. Observed Latitudes of the following places. Aleppo. Lat. North 36'' 12' Antioch 36" 10' Mount Cassius 36 4 Diarbekir 37 54 Seleucia in Syria 36 3 Bagdad 33 1 9 54" Immersion of u Virginis under the Moon, observed June 10, 1753, at Diarbekir, , near the Seraglio of the Bachaw. The Immersion of the Star at night 9** 48™ 4' The Emersion 9 39 47 The nitre is produced by a combination of the universal acid with the natrum of the ancients, as appears by observations. The asafoetida is drawn from a ferulaceous plant of the thapsia kind, which is very common in Media, &c. I have had the good luck to find the small nardus Indica: It is a gramineous plant, of which some bear spicaceous flowers, both male and female, and others only female ones. It is a valuable thing to botanists, as they are hitherto igno- rant of the true genus of this plant, though the root has been in use ever since the age of Dioscorides. This country is so dry, that electrical experiments often succeed without any stand of bitumen, pitch, silk, glass, &c. Our carpets and beavers are mostly sufficient to retain the electrical virtue, and prevent its spread- ing to the floor. Ten men standing upright, one before the other, have been made electrical, and, being touched, have produced sparks. VOL. XLIX.j PHILOSOPHICAL TRANSACTIONS. 6\g XLIL Some Observations, proving that the Fetus is in Part Nourished by the Liquor Amnii. By Malcolm Fleming, of Brigg, M.D. p. 254. July 25, 1753, being informed that a calF, come to full maturity, was just then brought forth dead in this town (Brigg, in Lincolnshire,) which had been alive, and appeared strong a very short time before its birth ; Dr. F. begged it of the owner, such instances being rare. The skin being of value, for it was an extraordinary large calf, it was sent to his house flayed. He first examined the thorax, which was his chief motive for begging it. He here adverts to the ex- periment of the lungs of a new-born animal sinking in water. After cutting out the lungs and heart, he clipped off a piece of the former with sharp scissars, about an oz. weight, or more, and threw it into a basin full of water. It quickly sunk to the bottom, and settled there. Immediately after, he blew into the remaining part of the lungs, through the trachea ; and though he could by that means distend them but very little, because the air flowed out readily through the cut bronchia, and therefore acted but faintly on the other parts ; yet a piece about the same size as the first, clipped off in the same manner, and thrown into the same basin, constantly kept at the top. This might seem foreign to his present purpose ; but he thought proper briefly to mention it here, not only on the account of the importance of the experiment, but likewise to show, that he was not misinformed in the account of the calf's being brought forth dead, and that it had not even respired ; much less taken any nourishment after exclusion, to influence the appearances described below. Having opened the abdomen, he observed the thick intestines, especially the rectum, extremely distended with an incredible quantity of meconium ; which for several inches above the anus was formed into distinct scybala or balls. He made an incision in the rectum, where it was very turgid, about 2 inches from the anus, and let out about 25 or 30 of these scybala ; which he laid on clean paper to dry, that he might examine them at his leisure. About 3 or 4 days after, when they were dry and brittle, and of the colour and consistence of aloes, he was surprised to find, on examination, every ball stuck full of tough, thick, white hairs, some of which were an inch long, or more. There seemed to be some scores in each, though, being shrunk with drying, they scarcely exceeded the bulk of an ordinary pea. This unexpected appearance set him oti consider- ing, whence these hairs had come; how got they there? and he could think on no other tolerable solution of the difficulty than to conclude that they belonged originally to the calfs skin; and, being loosened by maceration in the liquor amnii, were propelled into the stomach and intestines ; till they were at length entangled in the meconium. He was confirmed in the belief of this by being informed, on inquiry, that the calfs skin was white ; a circumstance unknown 4k 2 620 - PHILOSOPHICAL TRANSACTIONS. [aNNO J 755. to him before, it having been sent flayed. From this persuasion it was natural to infer that if hairs loosened from the skin of the fetus, and floating in the liquor amnii, can find a way into the intestines, and get entangled in the meconium, it is impossible but the liquor amnii must enter and pass through the whole alimen- tary passage along with them ; as a fluid may certainly penetrate where hairs cannot : but no good reason can be assigned, or even conceived, why hairs should be admitted where the fluid is excluded. The only reasonable scruple that remained to be got over was, that this being but a single instance, a general conclusion was not to be too hastily drawn from it ; that it was possible there might be some morbid concretions in the meconium of this particular calf, resembling hairs, which concretions in a common and na- tural way might be wanting ; or some preternatural communication between the primae viae in this subject, and the liquor amnii, not to be found in the gene- rality of other fetuses. But he afterwards received some of the first dung of other calves, in which he also found a great number of strong hairs all over; so as to leave no room for doubting but that this appearance is general in the me- conium of calves, in a natural way. The reader will please to observe that in neither of these instances he could be deceived, if he had ever so little reason to trust to the judgment and fidelity of those who supplied him with what he wanted. The colour and consistence of the meconium of a fetus is so very peculiar, and so widely difi^erent from that of faeces formed out of ingested aliments, that none, who have any knowledge in these matters, can mistake the one for the other. In the mean time he omitted not to open the embryos of the cow-kind, such as he could procure in the shambles of the market-town he lived in, and to examine their meconium. The 2 most advanced towards maturity, which he met with, had stiff long hairs about the mouth, the eye-brows, the ears, and navel, and a good many on the end of the tail ; but none on their skins. In neither of these, any more than in the younger embryos which he examined, was there so much as a single hair to be found in the meconium ; for this plain reason, if he judged right, because they had not got hairs on their bodies of long enough continuance to become loose, and float in the liquor amnii. But as opportunities of coming at fetuses of this species, especially such as are remarkably nearer to maturity than those 2 just now mentioned, are rare, he tried to supply that defect by opening those of other animals. Accordingly he procured 6 puppies, of the butcher-dog kind, brought forth at the full time at one litter. Having taken out the whole meconium of every one of them, after the strictest search he could find no hairs in any part of it. He had likewise an opportunity of opening a colt that died either in the birth, at the full time, or immediately after, before its meconium was discharged ; which he found in great VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 621 quantities in its rectum and colon. But neither here could he spy a single hair, though he examined whole pounds of it, and that portion most carefully which was lodged in the rectum, near the anus. These observations might seem at first view to clash with and contradict those he had related : but, on closer consideration, they would be found in reality to confirm them, for this reason, that puppies and colts, when brought forth, have no loose hairs on their bodies; but calves have in great numbers. In the puppies and colt, which he examined, the hairs were so firmly rooted on their skins, that he could scarcely pull any off with his thumb and fingers ; whereas in a mature calf, new brought forth, many are found quite loosened at their roots, and only adhering to their skin by the moisture on it. Therefore in the latter species hairs from the surface may be, and actually are, incorporated with the liquor amnii, and along with it enter the mouth and alimentary canal, which cannot be the case in the former. From these facts Dr. F. infers that the liquor amnii is in a constant natural way received into the mouth, stomach, and in- testines, and therefore must contribute to the nutrition of the fetus. XLIIL On the Success of Agaric in Amputations, &c. By Mr. William Thorn- hill, late Surgeon to the Infirmary at Bristol, p. 264. Mr. T. here states that he had employed the agaric successfully in 4 cases of amputation. XLIF. A Lunar Eclipse observed at Elbing, March 27 and 28, 1/55. By John Mendes Sachetlo Barbosa, F. R. S., and Prof, of Philos. and Physic. p. 265. 27^ lO** 51™ 15' the beginning was certain. 28 1 27 40 the end of the real eclipse. 131 30 the peimmbra certainly ended, XLV. On the Number of People in England. By the Rev. tVm. Brahenridge, D. D., Rector of St. Michael Bassishaw, London, and F.R.S. p. 268. There seems to be only two ways of discovering the number of people in England, where at present there are no capitation taxes ; either by the number of houses, or the quantity of bread consumed. As to the first, it is evident that if the number of houses could be determined, it would then be very easy to compute nearly the number of people. For it might be ejisily known by trial what number, at an average, could be allowed to each house, and from thence the whole number of people deduced. In a former letter Dr. B. assigned 6 to a house in town, which he found to be the nearest number, in some parishes, by an account taken ; but he thinks it is still more plain in the country that 6 is 522 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. the number to be fixed on, where people do not go so much into single life, and where there are not so many lodgers. For if we consider that for every marriage there are four births, on an average, as Dr. Derham, Major Graunt, and others have shown, and which Dr. B. found to be true from the registers both in the town and country ; consequently, allowing for deaths, there cannot be 3 children that survive from every marriage to mature age, and indeed not much above 2, as appears from Dr. Halley's table of the probability of life. Therefore every family, where there are children, one with another, cannot consist of more than between 4 and 5 persons, besides servants or inmates : which shows plainly that families, where there are children, cannot be estimated at more than 6 to a house, and where there are no children they cannot be reckoned more at an average. The number then being 6 to be assumed, let us next consider what number of houses is to be supposed. That Dr. B. might come at some certainty in this, he applied to one of the public offices, where he thought they could very likely give an account of them ; and he there found, that before the year ] 7 10. and near about that time, an account had been taken of all the houses throughout England and Wales, in order for some assessment upon them ; and the number then amounted to 7290'18. In which it may be supposed that a number of cottages were omitted that might be improper for that assessment ; but he thinks there could not possibly be above a 4th part of that number more : for surely the surveyors, if they had any care of the public revenue, would never omit above one in 5. Let us therefore suppose, that there might be a 4th part of that number more; and then those omitted will be about 182262, and the whole number of houses could not exceed 91 1310. If now we take Q11310 for the number, it is evident, if we allow 6 persons to a house at an average, the number of persons in England and Wales, before the year 17 10, could not be above 5467860. And since that time, 45 years ago, by a method of computing which he shows below, the increase could not be above 789558; and so the whole number of people now must be about 6257418 ; or six millions, all ages included ; for it must be remembered that in our wars, since 17 10, there could not be fewer lost than 200000, which is to be deducted from that number. As to the other way of determining this, by considering the quantity of bread consumed, it may perhaps at first view appear more uncertain ; but it will, he thinks, from some things that may be observed, at least help to ascertain the above number. For it is plain, if the quantity of wheat that is produced in England could be known, it would then be very easy to make the computation, as it might be nearly discovered, by a little observation, what each person at an average might consume. But the great difficulty is to find out nearly the quan- VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS^. 623 tity of wheat ; and there seems to be no way at present of knowing it, but by considering what proportion it may have to the barley ; for the quantity of that is nearly known from the malt-tax. Now, if we compare the quantity of the wheat in England, it is evident, that there is at least as much ground sowed with the one as with the other. For there are vast tracts of land that will not bear good wheat, but are frequently sowed with barley; and even those lands that will produce good wheat, they are often alternately sowed with it : the land that is rich and well manured, after one crop of wheat it is usual to sow it with barley. And if this be admitted that the quantity of land sowed with the one is equal to that sowed with the other, there must then be a much greater quan- tity of barley; because the same number of acres will produce much more of it, and generally in a greater proportion than 3 to 2. If then we assume that the barley used in malt is to the wheat used in food at home, as 3 to 2, we shall then be able to compute the quantity of each of them in this manner: the malt- tax from the year J 747 to the year 1753 inclu- sive, amounted to the sum of 4,254,8131. of which the 7 th part, the tax for one year, is607830l. and as the tax is 4 shillings on every quarter of barley, it follows that there are 303gi30 quarters of barley consumed yearly in malt; and therefore there must be 2026100 quarters of wheat consumed at home. Now, as it is known, that labouring healthy people at an average consume about one quarter of wheat in the year, which is about 5 12 lb. of flour, or lib. 6oz. in a day, we may allow that healthy and unhealthy, grown people and children, do not consume the half of that quantity, one with another. And therefore, that we may make the consumption of each person at an average as small as can reasonably be imagined, we will suppose that 3 people, children in- cluded, do not consume more than one hearty labouring person, that is one quarter in the year, or each person about 7 oz. in a day ; and by this supposition the above number of quarters of wheat 2026 100, consumed at home, will be sufficient for 6078300, or six millions of people. And this quantity of a quarter to 3 persons, though it appears too little, may be admitted, as in some of the northern countries they use some oat-bread and rye-bread; and every healthy person may, one with another, be allowed to consume this quantity at least. From this calculation it seems that there cannot be above 6 millions of people in England. And as, from the other method of computing from houses, we found the number to be about 6,257400, from which at least 200,000 is to be taken for those lost in the wars since 1710, or near that time; it appears that both these calculations confirm each other, and that the number of people may be considered at about 6 millions, or rather less. In which, according to Dr. Halley's nile, there will be about 1 5 hundred thousand men able to carry arms. Dr. Derham, from the computations of Mr. King, supposes there is about 5+ 624 PHILOSOPHICAL TRANSACTIONS. [aNNO J 755. millions of people in England ; to which, if we add the increase that may be since that time, the number will be near about what we have made them. But Sir William Petty has endeavoured to make them, in his time, no less than 7369000, by supposing them to be in proportion to the assessment, then 1 1 times greater than that in the city of London. In which, with regard to the city, he was certainly mistaken, as Dr. B. showed last year ; for the number at that time, in l682, was not much above 504000, and therefose 11 times that, viz. 5544000 must, according to his own hypothesis, be the number of people in England. And if we allow 1355000 to be the increase in about 73 years since that time, the number could not be now, according to that assessment, above Sspgooo. From which we ought at least to subtract 400000, which may be justly allowed for loss in our wars since 169O; and the remainder 6499000 is not half a mil- lion more than we have made them. The people then being computed at 6 millions, or rather less, it appears that Englanrl is but thinly peopled. For not only the exportation of at least 400,000 quarters of wheat annually shows plainly that we want people to consume it at home, and that we maintain in bread about a million of foreigners abroad : but if we examine more particularly, we shall find that the country is capable of supporting one-half more inhabitants, or 9 millions. But in Ireland the case is still worse: for if there is but a million of people, as is commonly supposed, and according to Mr. Templeman 27400 square miles, which is 17,536,000 acres, and a 4th or more be supposed waste; then there will be at least 12,000,000 good acres. And consequently if 4 acres in that country be allowed sufficient, at an average, for the maintenance of one person, Ireland, if duly cultivated, could maintain 2 millions more people than it has now, or 3 times its present number of inhabitants. And in Scotland, if there be, as is said, but a million and a half of people, for at present I know no way to compute them, and 27700 square miles, or 17,728,000 acres, and -f be sup- posed waste, which isv'tiot too much in that country, then there will be 1 1,000,000 good acres; of which, if we suppose that 5 acres of that soil is not more than sufficient for each person, then there may be provision for 2,200,0000 people, or more, with the advantages of fishing, that is 7OOOOO more than there are at present. From all which it is plain, that if the land in both the British isles was duly cultivated, they might sustain about 6 millions more people than they do now; that is as many more people as England now contains. And here, by the way, it may be observed, if we extend our thoughts to the whole globe of the earth, and compare the quantity of land with the number of people, we shall find that it will maintain above 26 times the present number of mankind. The proportion being given of the living to the dead in one year, and also the proportion of the births to the dead, the number of the people being unknown; VOL. XLIX.3 PHILOSOPHICAL TRANSACTIONS. 625 to find in what time the people shall be in any given proportion, to what they are at present. Suppose n to be the unknown number of the people at present, and let the living be to the dead, in one year, as / to ], and the dead to the births as 1 to b, the proportion given to what their number is at present as p to 1 , and the number of years required to be y. It is plain then, that the dead at the end of the first year will be - , and the births y, and the whole number of people must hen -\- j. In like manner, at the end of the 2d year, the dead will be v-^ , and the births — r" ~ " , and the whole number of people . I , bn n , Ibn + hbn — nb , n — In — bn J + 6 — 1, ., . , must be n + y — y -j ~ 1 ^ = {-^ yn. And so at the end of the 3d year the number of people will be ( -^^— )^«. From which at length it is evident by induction, that the number of people at the end of the required number of years will be ( ■,-^^) n. . But as the proportion is then to beas j& to 1, we shall have ( — j^^-Yn = pn, and thence (/ + b — \y = pi". And because the logarithms of equal quantities must be equal, we shall have y X log. (/ + i - 1) = log.p + 7/ X log. /, and alsoy = _^^-J°liL_-_. And therefore the number of years y is determined by the logarithms of known quantities, when the people shall be in the given proportion of /> to 1 . It may be observed that the quantity ( j-^^)*/j may be considered as the or- dinate of the logarithmic curve, whose abscisse is the index y, and that the ordi- nate passing through the beginning of the abscisse, where y = o, must be equal to n. If now it be required to know when the people shall be doubled; let us sub- stitute in the above formula, instead of b, I, p, the respective numbers 1.12, 40, 2. and it will be w = , — -^f^ — rr ; — —; and then the logarithms being •^ log. (40 + 1.12 — 1) — log. 40 o o taken we shall have y = ' — = 231; which shows that, according to the present state of births and burials, the people could not be doubled in less than 231 years. And by the same method it appears, changing the signs o( b — 1, that 230 years ago, in the time of Henry the 8th, the number could not be above -^ of what it is now, that is about 3 millions. And so if we were to find, when the number of people in England would be increased to Q millions, which, by what has been said above, is near about the outmost that can be maintained, from the natural produce of the country; we should then have/) = -J- = 1.5, because Q millions is to the present number as o* „ J 1 log. 1.5 ,' 0,17609!3 ,„^ ... 3 to 2, and also y = ^--^-^^--—^— = -^^^^ = 135; which VOL. X. 4L 626 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. shows that, at the present rate of births and burials, it must be 135 years before England can be fully peopled. If we suppose, as Sir William Petty does, that the burials are to the births as 9 to 10, that is 1 to 1.11 1, which is something less than that of Dr. Derham's proportion, and that 1 dies in 40 in a year; if we substitute these numbers in the formula, we shall then find the time of doubling to be 250 years. For then .. ■•! , log 2 0,3010300 , . , itwill be^ = ,^^^— — -■--^— — ^= — j^^-- = 250; which shows how far Sir William was mistaken in his method of calculation, when he made the time to be 36o years. After the same manner, the number of years being given, it will be easy to find the proportional increase. Suppose after 45 years. For then we should have 45 x log. (/ + i — 1) — 45 X log. / = log. p; which will give 45 X O.OOiaoOQ = log./), and therefore p = 1.1443, from which if n be equal to 5,467,860, we have pn = 6,256,872. So that it appears if there was 5,467,860 people in England at the year 17 10, when the above-mentioned survey was made, there is now 6,250,000; if none were to be deducted on account of our wars, and emigrations to our colonies since that time. From what has been found above, that {I -\- b — \y = ply, it is evident, that the ratio of the increase in any number of years may be determined, without the number of people being known, or their proportion to the annual increase ; and also that any one of the quantities /, b, y, p, may be found, the others being known. But if the ratio of the number of people to the annual increase be known; and consequently the proportion, of the number in any one year, to the number next year known, we shall then have a very simple equation. For if we suppose the number of people in any one year, to be to that number with the increase added in the next year, as 1 to r, we shall then have nr' = vp, or r' = /;. And, in like manner, if the proportion of the number of people to their increase, in a given cycle of years, had only been known, and that cycle y y be c, we should then have nic = np, or n = p. From which formula it would be easy to calculate the numbers of mankind, in all ages through the world, if we suppose them to arise from a given number, and the rate of increase known, in any period of years. And this may sometimes be of use to discover the number in any age, that might be possible to reason on, and to find out the truth of any hypothesis. XLVI. An Attempt to Explain Tivo Roman Inscriptions, cut on tivo Altars, which were dug up some time since at Bath. By John tVard, LL.D- and V. P. R. S. p. 285. These two inscriptions were found near the same time and place, with that VOL. XLIX.] rHILOSOPHICAL TRANSACTIONS. 62/ which has been already published in the 48th vol. of the Philos. Trans. The altars, which contain them, are in the possession of Dr. William Oliver, physi- cian at Bath, who has placed them in his garden, and who transmitted draughts of them, with their inscriptions, taken by the Rev. Mr. Borlase, f.r.s. And after that, Mr. Prince Hoare sent casts of the inscriptions in plaster of Paris. The inscTiption on the higher altar may, Dr. W. thinks, be thus read in words at length: Peregrinus Secundijilius, civis Trever, Jovi Cetio, Marti, et Nemetona, votum solvit libens merito. The person, who dedicated this altar, calls himself Peregrinvs Secvndi FiLivs ; each of which names occurs several times in Gruter, as a cognomen, which often stands alone, when the person named is sufficiently distinguished by it. Having given us his own name, and that of his father, he proceeds to ac- quaint us with his country, and stiles himself Civis Trever, a people who in- habited that part of Belgic Gaul between the Maese and the Rhine, which is now the electorate of Triers; and were conquered by Caesar, with the rest of the Gallic nations. Their chief city, which was situated on the Moselle, being made a Roman colony in the reign of Augustus, is by Tacitus called Colonia Treverorum, but by others more frec^uently Augusta Treverorum, and now Triers. The 3 following lines of the inscription contain the names of 3 deities, to whom this altar was dedicated. The first of these is here called Ivpiter Cetivs. Ptolemy makes mention of a large mountain in Germany, which he calls Kino?, and describes as the eastern boundary of Noricum, by which it was separated from Pannonia, now Hungary. From this mountain it seems highly probable, that the name Cetius might be given to Jupiter, as its tutelar deity. The 3d and last name here mentioned, is Nemetona, which Dr. W. had no where else met with ; but as it stands connected with the two former by the par- ticle ET, it must, he thinks, denote some deity, and by the termination a god- dess. The last line of the inscription acquaints us with the cause of erecting this altar, which was the performance of some vow, formerly made by Peregrinus. And it is not improbable, that he had laboured under some bodily disorder, which occasioned his going to Bath for the benefit of the waters, which in the time of the Romans were in so high esteem. And the good success which he met with by the use of them, may be concluded from the tenor of the inscrip- tion, wherein he makes his acknowledgement to the deities above-mentioned, for the benefit he had received through their favour, in consequence of his ad- dresses to them for that purpose. For as it was a common notion of the ancient pagans, that all human affairs were under the direction of their deities; so in any danger or misfortune they used to solicit them for relief, with vows and pro- 4l'2 628 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. mises of erecting altars and other buildings to their honour, in case of a favour- able answer. Which, when performed, they were said votum solvere, as the letters v. s. here imply. The other inscription, on the lower altar, when expressed in words at length, may be read in the following manner: Sulevis Sulinus Scultor, Bruce li Jilius, sacrum fecit libens merito. That the first word Svlevis denotes a name given to certain rural goddesses, called Sulevae, is plain from an inscription found on a stone at Rome, and pub- lished by Fabretti, in which they are joined with Campestris. The 2 next words, SvLiNvs ScvLTOR, must, he thinks, stand for the names of the person who dedicated this altar; as the 2 following, Brvceti f. acquaint us with that of his father. The words Sacrvm fecit, in the last line, are of the same import with dedicavit; in which sense likewise sacrum alone is often used. And some times the reason of the dedication is added, as, sacrum, voto suscepto, fecit, in Gruter. But that not being mentioned here, must remain unknown. There is nothing said in either of these inscriptions, which can afford any light towards settling the time, when they were erected. But so far as appears from the form of the letters, they may not improbably be supposed of somewhat a later date, than that mentioned before, as found near the same place. XLVII. Of a remarkable Echinus. By Gust. Brander, Esq. F.R.S. p. 295. . This echinus was of a very singular species. It appeared to be of a middle nature between the echinus and the star-fish. It came from the island of Bourbon in the East Indies, and he could not learn that it was any where described. See fig. 10, pi. xi. XLFIII. Of an Impression on a Stone dug up in the Island of Antigua, and the Quantity of Rain fallen there for 4 Years. By the Rev. Francis Byam. p. 295. This stone was brought from a quarry for a building in the town of An- tigua: the quarry is in the side of a mountain, and is about 300 yards higher than high-water mark, and about 2 miles from the sea. When the mason struck it with his hammer it split in two, and discovered the exact figure of a fish, on each stone, called an old wife. The quantity of rain that fell in Antigua, was in 1751, 51.8 inches; in 1752, 43.3 inches; in 1753, 32.8 inches; in 1754, 75.2 inches. XLIX. On the Stones mentioned in the Preceding Article. By Mr. Arthur Pond, F. R. S. p. 297. The impression of this fish is in a chalky kind of stone, of a pale ochrey co- VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. . 62Q lour ; some parts, when scraped, are white, and all the impression is of a yellow- ish brown, nearly the colour of brown ochre. The impressions of the bones and iins are verj' perfect; and the cavity, that contained the back-bone, ex- tremely sharp and delicate. When Mr. P. first saw it, '2 or 3 of the vertebrae were in it. All the cavities of the bones are now sufficiently open to contain them, and it is probable that most, if not all of them, were in the stone, when it was first split. Between the rib-bones and the two long fins, which come down from the head, which parts were only fleshy, there is no impression, the stone having united quite through ; and on the upper part of the fin, by the side of the cheek, is a deep impression of a very small cockle-shell. The im- pression on the counter-part of the stone is much the same, except that the tail is wanting. L. On the Ejects of Lightning in the Danish Church, in JVellclose-square. By Gustavus Brander, Esq., F. R. S. p. 298. On Monday, Nov. 17, between 6 and 7 o'clock, there was, among many others, one most amazing flash, accompanied with a clap of thunder, that equalled in report the largest cannon. The next morning, the minister observ- ing the church clock to be silent, they went into the belfry, and found the wire and chain, that communicated from the clock in the belfry, to the clapper in the turret, where the bells hang, were melted ; and that the small bar of iron from the clock, that gives motion to the chain and wire, just where the chain was fastened, was melted half through, the bar being about -f- of an inch broad, and half an inch thick. By several links of the chain, and of the wire, it is ob- served, that the lightning took effect only in the joints. But whether it entered by communication, from the wire exposed to the air in the small turret, through the roof of the belfry, or at the windows, there being several panes broken in the south and west corners, is uncertain ; though Mr. B. presumes rather the first way, as it is very possible, that the bare report of the thunder might have oc- casioned the latter. The pieces of the wire and chain were scattered over the whole belfry, nor could it be discerned, that the wood-work, or ought else, had suffered. LI. Electrical Experiments, made in Pursuance of those hy Mr. Canton, dated Dec. 3, 1753; with Explanations. By Mr. Benjamin Franklin, F.R.S. Dated Philadelphia, March \ A, 1755. p. 300. Principles. — 1. Electric atmospheres, that flow round non-electric bodies, being brought near each other, do not readily mix and unite into one atmosphere. 630 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. but remain separate, and repel each other. This is plainly seen in suspended cork balls, and other bodies electrified. 2. An electric atmosphere not only repels another electric atmosphere, but will also repel the electric matter contained in the substance of a body approach- ing it ; and, without joining or mixing with it, force it to other parts of the body, that contained it. This is shown by some of the following experiments. 3. Bodies electrified negatively, or deprived of their natural quantity of elec- tricity, repel each other, (or at least appear to do so, by a mutual receding) as well as those electrified positively, or which have electric atmospheres. This is shown by applying the negatively charged wire of a phial to two cork balls, sus- pended by silk threads, and by many other experiments. Preparation. — Fix a tassel of 15 or 20 threads, 3 inches long, at one end of a tin prime conductor ; (mine is about 5 feet long, and 4 inches diameter) sup- ported by silk lines. Let the threads be a little damp, but not wet. Exper. 1 . — Pass an excited glass tube near the other end of the prime con- ductor, so as to give it some sparks, and the threads will diverge. — Because each thread, as well as the prime conductor, has acquired an elastic atmosphere, which repels, and is repelled by, the atmospheres of the other threads : if those several atmospheres would readily mix, the threads might unite, and hang in the middle of one atmosphere, common to them all. Rub the tube afresh, and approach the prime conductor with it, crossways, near that end, but nigh enough to give sparks ; and the threads will diverge a little more. Because the atmosphere of the prime conductor is pressed by the atmosphere of the excited tube, and driven towards the end where the threads are, by which each thread acquires more atmosphere. Withdraw the tube, and they will close as much. — They close as much, and no more, because the atmosphere of the glass tube, not having mixed with the atmosphere of the prime conductor, is withdrawn entire, having made no addition to, or diminution from, it. Bring the excited tube under the tuft of threads, and they will close a little. — They close, because the atmosphere of the glass tube repels their atmospheres, and drives part of them back on the prime conductor. Withdraw it, and they will diverge as much. — For the portion of atmosphere, which they had lost, returns to them again. * Exper. 2. — Excite the glass tube, and approach the prime conductor with it, holding it across, near the opposite end, to that on which the threads hang, at the distance of 5 or 6 inches. Keep it there a few seconds, and the threads of the tassels will diverge. Withdraw it, and they will close. — They diverge, be- cause they have received electric atmospheres from the electric matter befor6 VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 631 contained in the substance of the prime conductor ; but which is now repelled and driven away, by the atmosphere of the glass tube, from the parts of the prime conductor, opposite and nearest to that atmosphere, and forced out upon the surface of the prime conductor at its other end, and on the threads hanging to it. Were it any part of the atmosphere of the glass tube, that flowed over and along the prime conductor to the threads, and gave them atmospheres (as in the case when a spark is given to the prime conductor, from the glass tube), such part of the tube's atmosphere would have remained, and the threads con- tinue to diverge; but they close on withdrawing the tube, because the tube takes with it all its own atmosphere, and the electric matter, which had been driven out of the substance of the prime conductor, and formed atmospheres round the threads, is thereby permitted to return to its place. Take a spark from the prime conductor, near the threads, when they are di- verged as before, and they will close. — J'or by so doing you take away their at- mospheres, composed of the electric matter driven out of the substance of the prime conductor, as aforesaid, by the rejiellency of the atmosphere of the glass tube. By taking this spark, you rob the prime conductor of part of its natural quantity of the electric matter ; which part so taken is not supplied by the glass tube; for when that is afterwards withdrawn, it takes with it its whole atmo- sphere, and leaves the prime conductor electrized negatively, as appears by the next operation. Then withdraw the tube, and they will open again. — For now the electric matter in the prime conductor, returning to its equilibrium, or equal diffusion, in all parts of its substance, and the prime conductor having lost some of its na- tural quantity, the threads connected with it lose part of theirs, and so are elec- trized negatively, and therefore repel each other, by Pr. 3. Approach the prime conductor with the tube near the same place as at first, and they will close again. — Because the part of their natural quantity of electric fluid, which they had lost, is now restored to them again, by the repulsion of the glass tube forcing that fluid to them from other parts of the prime conduc- tor : so they are now again in their natural state. Withdraw it, and they will open again. — For what had been restored to them is now taken from them again, flowing back into the prime conductor, and leaving them once more electrized negatively. Bring the excited tube under the threads, and they will diverge more. — Be- cause more of their natural quantity is driven from them into the prime conduc- tor, and so their negative electricity increased. Exper. 3. — The prime conductor not being electrified, bring the excited tube under the tassel, and the threads will diverge. — Part of their natural quantity is 63a PHILOSOPHICAL TRANSACTIONS. [anNO 1755. thus driven out of them into the prime conductor, and they become negatively electrized, and therefore repel each other. Keeping the tube in the same place with one hand, attempt to touch the threads with the finger of the other hand, and they will recede from the finger. — Because the finger being plunged into the atmosphere of the glass tube, as well as the threads, part of its natural quantity is driven back through the hand and body, by that atmosphere, and the finger becomes, as well as the threads, nega- tively electrized, and so repels, and is repelled by them. To confirm this, hold a slender light lock of cotton, 2 or 3 inches long, near a prime conductor, that is electrified by a glass globe, or tube. You will see the cotton stretch itself out towards the prime conductor. Attempt to touch it with the finger of the other hand, and it will be repelled by the finger. Approach it with a positively charged wire of a bottle, and it will fly to the wire. Bring near it a negatively charged wire of a bottle, it will recede from that wire in the same manner, that it did from the finger ; which demonstrates the finger to be negatively electrized, as well as the lock of cotton so situated. LII. Extract of a Letter concerning Electricity, from Mr. B. Franklin to Mons. Delibard, inclosed in a Letter to Mr. Peter Collinson, F. R. S. Dated Philadelphia, June 29, 1755. p. 305. You desire my opinion of Pere Beccaria's Italian book. I have read it with much pleasure, and think it one of the best pieces on the subject, that I have seen in any language. Yet as to the article of water-spouts, I am not at present of his sentiments ; though I must own with you, that he has handled it very ingeniously. Mr. Collinson has my opinion of whirlwinds and waterspouts at large, written some time since. I know not whether they will be published ; if not, I well get them transcribed for your perusal. It does not appear to me, that Pere Beccaria doubts of the absolute impermeability of glass in the sense I mean it ; for the instances he gives of holes made through glass by the electric stroke, are such as we have all experienced, and only show that the electric fluid could not pass without making a hole. In the same manner we say, glass is impermeable to water, and yet a stream from a fire-engine will force through the strongest panes of a window. As to the eft'ect of points in drawing the elec- tric matter from clouds, and thereby securing buildings, &c. which, you say, he seems to doubt, I must own I think he only speaks modestly and judiciously. I find I have been but partly understood in that matter. I have mentioned it in several of my letters, and except once, alwavs in the alternative, viz. that pointed rods erected on buildings, and communicating with the moist earth, would either prevent a stroke, or, if not prevented, would conduct it, so as that the building TOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 633 should suffer no damage. Yet whenever my opinion is examined in Europe, nothing is considered but the probability of those ro 2 or 3 weeks after. about perihelion. 1, 2, or 3 weeks. ■ N. increasing 2 to 5 weeks before. }■ Small increasing N. Small S. or N Small S 1 Small S. or N. / very faint . 5 to 8 weeks before. 2 months before perihel. 2 or 3 months. 3 months before perihel. 11 to 14 weeks. LVIII. An Extraordinary and Surprising Agitation of the tVaters, though * without any perceptible Motion of the Earth, having been observed in various Parts of this Island, both Maritime and Inland, on the same Day, and chiefly about the Time that the more Ftolent Commotions of both Earth and IVaters * See the note on the letter from R. Philips. — Orig. TOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 647 SO extensively/ affected many very distant Parts of the Globe',* the folloiviw Accounts, relating to the former, were transmitted to the Society ; in which are specified the Times and Places when and where they happened. J. At Portsmouth, in Hampshire. By Mr. John Robertson, F. R. S. p. 351. On Saturday, Nov. 1, 1755, about 35 minutes after 10 in the morning, there was observed in the dock-yard at Portsmouth, an extraordinary motion of the waters in the north dock, and in the basin, and at two of the jetty-heads. In the north dock, whose length is about 229 feet, breadth 74 feet, and at that time about 1 7-r '^et depth of water, shut in by a pair of strong gates, well se- cured, his majesty's ship the Gosport of 40 guns, was just let in to be docked, and well stayed by guys and hawsers. On a sudden the ship ran backwards near 3 feet, and then forwards as much, and at the same time she alternately pitched with her stem and head to the depth of near 3 feet ; and by the libration of the water, the gates alternately opened and shut, receding from each other near 4 inches. In the basin, whose length is about 240 feet, breadth 220 feet, and at that time about 17 feet depth of water, shut in by two pair of gates, lay the Berwick of 70 guns, the Dover of 40 guns, both in a direction nearly parallel to the Grosport ; and a merchant ship of about 600 tons, unloading tar, lying in an oblique direction to the others. These ships were observed to be agitated in like manner with the Gosport, and the tar-ship to roll from side to side : the swell of the water against the sides of the basin was observed to be 9 inches ; one of the workmen measured it between the librations. The Nassau, a 70-gun ship, lying along side a jetty head, between the north dock and the basin ; also the Duke, a QO-gun ship, lying against the next jetty- head, to the southward, both in a direction nearly at right angles to the others, were observed to be rocked in the same manner, but not quite so violently : these 2 ships lay in the harbour. The dock and basin lie nearly east and west, on the west side of the harbour. 2. In Sussex, and the Southern Parts of Surrey. By Philip Carteret JVebb, Esq., F. R. S. p. 353. In his garden at Busbridge, near Godalmin in Surrey, on Saturday the first of November 1755, at half an hour after 10 in the forenoon, Philip Smith, John Street, and John Johnson, the gardeners, were alarmed by a very unusual noise in the water, at the east end of the long canal, near which John Street and John Johnson were then at work. On looking that way, they observed the water, in that part of the canal, in great agitation, attended with a considerable • This agitation of the waters, observed in various'parts of Great Britain, happened on the very satne day with the memorable earthquake at Lisbon. 6j8 philosophical transactions. [anno 1755i noise. The water soon raised itself in a heap or ridge, extending lengthwise about 30 yards, and between 1 and 3 feet above the usual level of the water ; after which the heap or ridge heeled or vibrated towards the north, or left side of the canal, with great force, and flowed about 8 feet over the grass walk on that side of the canal, quite up to the arch. On the water's returning back into the canal, it again raised itself into a heap or ridge in the middle; after which the heap or ridge heeled or vibrated with greater force towards the south, or right hand side of the canal, and flowed over the grass walk, and through the rustic arch on that side ; and drove a small stream of water, which runs through it, 36 feet back upwards, towards its source. During this latter motion, the bot- tom of the canal, on the north side, for several feet in width, was quite bare of water. The water being returned into the canal, the vibrations became less and less, but so strong as to make the water flow several times over the south bank of the canal, which is not so high as the north bank. In about a quarter of an hour from the first appearance the water became quiet and smooth as before." The motion of the water was, during the whole time, attended with a great per- turbation of the sand from the bottom of the canal, and with a great noise, likened by the gardeners to that of water turning a mill. During the whole time the weather was remarkably still, there not being the least wind ; and there was no tremor or motion of the earth felt on the sides of the canal. The canal is near 700 feet long from west to east, and is about 58 wide : there is a small spring, which constantly runs through it. The water at the east end, where this appearance was observed, usually pens from 2 to 4 feet, being gradu- ally deeper to the west end, where it pens to about 10 feet. No motion was taken notice of in the water at the west end of the canal, the first vibration, which drove the water over the grass walks, was from south to north. The grass walk on the north side of the east end of the canal is 14 inches, and that on the south side about 10 inches higher than the usual level of the water: the highest part of the walk, over which the water flowed, is about 20 inches above the water-level. Mr. W. was informed, that the water was affected about the same time in the following places. In a mill-pond, at Medhurst in Sussex, the sudden agita- tion and swell of the water rolling toward the mill was so remarkable, that the miller imagined a sluice had been opened at the upper end of the pond, and had let a back-water into it ; but on search it was found to be shut as usual. Below the mill the swell of the water was so great, as to drive the stream upwards, back into the conduit of the mill. At Lee, in the parish of Whitley, in Surrey, about 5 miles from Busbridge, between Busbridge and Medhurst; the water in a canal or pond belonging to Mr. Luff was so violently agitated, that the gardener, on the first appearance, ran for help, thinking a number of otters were under the VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 649 water, destroying the fish. In a mill-pond, near Guildford in Surrey, a like swell and agitation of the water was observed by several persons, one of whom stood all the time on a bridge of wood, over the pond. Not the least tremor or motion of the earth was felt in any of these places, or at the bridge at Guildford. 3. In the Parish of Cobham. By Sivithin Adee, of Guildford, M.D., F.R.S. p. 357. A man, in the parish of Cobham, was watering a horse in hand, at a pond close by the house, which is fed by springs, and had no current. The time he fixes was about 10 in the morning, but their clock goes too slow. While the horse was drinking, the water ran away from the horse, and moved towards the south with swiftness, and in such a quantity, as left the bottom of the pond bare ; then returned with such impetuosity, as made the man leap backwards, to secure himself from the sudden approach of the water. It went back again to the south, with a great swell, and returned agiiiii. On inspecting the place, Dr. A. found the water must have risen above 1 foot. The ducks were alarmed at the first agitation, and flew all instantly out of the pond. The man observed, that there was a particular calm at this time of day. You will observe here were tw.o fluxes and two refluxes seen distinctly. 4. At Medhursl. By Mr. John Hodgson, p. 358. As to the ponds near Medhurst, every body agrees, that there was an extra- ordinary swelling of the water. The water was thrown several feet above its banks, both at north-mill, at south-pond, and the pond in Lord Montacute's park; and at the first of these, on its retreat, left some fishes on dry land. 5. At Cranbrook in Kent. By Wm. Tempest, Esq. F.R.S. p. 36o. The people here are very much alarmed on account of an earthquake, which happened last Saturday (Nov. the 1st). I felt nothing of it, but some people fancied they did. I do not hear that the earth moved ; only the waters of several ponds, in this and the adjacent parishes, were in such motion, that they over- flowed their banks, then returned back, and overflowed the other side. 6. Near Tunbridge. By John Pringle, M. D., F. R. S. p. 36o. The pond at Eaton-bridge, near Tunbridge, is about an acre in size, and across it is a post and rail, which is almost quite covered by the water. Some people heard a noise in the water, and imagining something had tumbled in, ran to see what was the matter; when, to their surprise, they saw the water open in the middle, so as that they could see the post and rail a good way down, almost to the bottom, and the water dashing up over a bank about 2 feet high, and per- pendicular to the pond. This it did several times, making a grejit noise. They did not feel the least motion on the shore, nor wa.s there any wind, but a dead calm. VOL. X. * 4 O «» 650 PHILOSOPHICAL TRANSACTIONS. [aNNO 1753. 7. In the River Thames, near Rotherhiihe. By Mr. Henry Mills, p. 36 1. Being in one of his barges, unloading some timber, between 11 and 12 o'clock, he was surprised by a sudden heaving up of the barge from a swell of the water, not unlike what happens when a ship is launched from any of the builders' yards in the neighbourhood. After the barge had alternately risen and sunk 3 or 4 times, with a motion gradually decreasing, the water became quiet again. 8. In Peerless Pool, near Old-street, London. By Tho. Birch, D. D. Secret. R. S. p. 362. On the reports, received from several gentlemen, that the agitation of the waters observed in many parts of England, Scotland, Ireland, Holland, &c. on Saturday Nov. 1, 1755, had been likewise noticed in Peerless Pool, near Old- street road, being curious to have as authentic and circumstantial an account as possible of a fact, which he had not heard to have been remarked in any other part of London, or its suburbs, Dr. B. went thither on Saturday Dec. 6, 1755, and took down the following particulars relating to it, from the mouth of one of the two waiters there, who were eye-witnesses of it. He being engaged between the hours of 10 and 11 in the morning, with his fellow-waiter, in some business near the wall inclosing the ground, which contains the fish-pond, and acci- dentally casting his eye on the water, was surprised to see it greatly moved with- out the least apparent cause, as the air was quite calm. This occasioned him to call to his companion to take notice of it, who at first neglected it, till being urged to attend to so extraordinary an appearance, he was equally struck with the sight of it. Large waves rolled slowly to and from the bank near them, at the east end, for some time, and at last left the bed of the pond dry for several feet, and in their reflux overflowed the bank 10 or 12 feet, as they did the oppo- site one, which was evident from the wetness of the ground about it. This mo- tion having continued 3 or 6 minutes, the two waiters stepped to the cold bath near the fish pond, to see what passed there; but no motion was observed in it by them, or by a gentleman who had been in it, and was then dressing himself, and who, on being told of the agitation in the fish pond, went directly thither, with the waiters, and was a third witness of it. On the ceasing of it, they all 3 went to the pleasure bath, between which and the fish pond the cold bath is situ- ated; but they found the said pleasure bath then motionless, but to have been agitated in the same manner with the fish pond, the water having left plain marks of its having overflowed the banks, and risen to the bushes on their sides. The motion in the fish pond had been also observed by some persons in a house be- longing to Mr. Kemp, the master of Peerless Pool, situated at a small distance from that pond, and commanding a full view of it. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 651 9. j4t Rochford in Essex. By the Rev. Mr. T/iomlinson. p. 364. At a pond in a close of Mr. Sly's, adjoining to the church-yard, the water was observed to flow a considerable way up the mouth of the pond, and then return- ing, to flow up the opposite side, repeating this sort of motion for about a quarter of an hour. The motion of the water in the pond was only from east to west, and from west to east, alternately. 10. In Berkshire, near Reading. By Mr. Rd. Philips, p. 365. On the 1 St of November last, at about 1 1 o'clock in the morning, as Mr. Pauncefort's gardener was standing by a fish pond in the garden, he felt a most violent* trembling of the earth, directly under his feet, which lasted upwards of 50 seconds; immediately after which he observed that the water in the pond was in a very unusual motion, and suddenly thrown on the opposite side, leaving that on which he stood quite dry, for the space of 1 yards, and continued in that state for about 1 minutes, when it returned as before, and collecting in or near the middle of the pond, rose about 20 inches above the level of the water on each side, and continued so for 2 minutes in violent agitation, which the gardener described to be like the boiling of a pot. At the same time Capt. Clarke, at Caversham in Oxfordshire, a mile distant from Reading, was alarmed with a very great noise, as if part of the house had been falling down; on examination however it did not appear that the house was at all damaged ; but a vine, which grew against it, was broken off, and 2 dwarf trees, such as are used in espalier hedges, were split by the shock. 11. Near Reading in Berkshire. By the Rev. J. Blair, LL.D., F.R.S. p. 36/. At Earley-court, near Reading in Berkshire, in a small fish pond near the house of Edward Pauncefort, Esq. the water was observed, about 1 1 o'clock in the forenoon, to be in a strong agitation, like that of the tide coming in. The first motion of the water was from the south end of the pond to the north end, leaving the ground or bottom of the fish pond on the south end without water, for the space of 6 feet. It then returned, and flowed at the south end, so as to rise 3 feet up the banks, and immediately went back again to the north, where it likewise flowed 3 feet up the banks; and in the time between the flux and reflux, the water swelled up in the middle of the pond like a ridge, or rising part of the land. This motion or agitation of the water, from south to north, and from north to south alternately, backwards and forwards, lasted about the space of 4 minutes of time; and there seemed to be little or no motion in the direction of east and west, the weather being perfectly calm during the whole time. * This is the only account that mentions any tremor of the earth to have accotnpanied the agita- tion of the waters in this island j and the next account of the very same matter docs uot take I lie least notice of any. — Orig. 4 o 2 ()5'2 PHILOSOPHICAL TRANSACTIONS. [aNNO J 755, 12. In Oxfordshire, at Shirburn Castle, the Seat of the Earl of Macclesfield, Pres. R. S. Communicated by his Son, the Lord discount Parker, F. R. S. then on the Spot. p. 368. On Saturday November 1, a little after 10 o'clock in the forenoon, walking in the garden at Shirburn castle, he perceived the gardener, who was coming to- wards him by the end of the moat, on a sudden stop short, and look earnestly into the water. He went towards him, and perceived immediately a very strange mo- tion in the water. There was a pretty thick fog, not a breath of air, and the surface of the water all over the moat was as smooth as a looking-glass; yet in that comer of the moat near which he stood, the water flowed into the shore, and retired again successively, in a surprising manner. The flux and reflux were quite regular. Every flood began gently; its velocity increased by degrees, till at last, with great impetuosity, it rushed in till it had reached its full height, at which it remained for a little while, and then again retired, at first gently ebb- ng, at last sinking away with such quickness, that it left a considerable quantity of water entangled among the pebbles, laid to defend the bank, which run thence in little streams over the shore, now deserted by the water, which at other times always covers it. As the slope of the sides of the moat is very gentle, the space left by the water at its reflux was considerable, though the difference be- tween the highest flood and lowest ebb of these little tides, was but about 4-i- inches perpendicular height; the whole body of water seeming to be violently thrown against the bank, and then retiring again, while the surface of the whole moat all the time continued quite smooth, without even the least wrinkle of a wave. He sent persons to several other ponds, in all which the agitation was very considerable. The swells, that succeeded each other, were not equal, nor did they increase or diminish gradually; for sometimes, after a very great swdl, the next 2 or 3 would be small, and then again would come a very large one, followed by 1 or 2 more as large, and then less again. 13. In Devonshire and Cornwall, at Plymouth, Mounts-Bay, Penzance, &c. By John Huxham, M. D., F. R. S. p. 371. Saturday, November 1, about 4 p.m. we had (just about high water) an ex- traordinary boar, as the sailors call it. The sea seemed disturbed about 20 mi- nutes before, though there was very little wind that day, or for some days before. One of our surgeons, who had then just crossed the ferry at Creston, a mile to the south-east of Plymouth, said, that the tide had made a very extraordinary out (or recess) almost immediately after high water (about 4 p. m.) left both the passage-boats, with some horses, and several persons, at once quite dry in the mud, though the minute or two before, in 4 or 5 feet water; in less than 8 •minutes the tide returned with the utmost rapidity, and floated both the boats again, so that they had near 6 feet water. The sea sunk and swelled, though in VOL, XLIX.] PHILOSOPHICAL TRANSACTIONS. 653 a much less degree, for near half an hour longer. It was said, that at the next morning's tide there were several very large surges. This boar drove several ships from their moorings, and broke some of the hawsers, and twirled the ships and vessels round in a very odd manner. At Crunill-passage, over another arm of the sea, about 2 miles west of Plymouth, the same phenomena were obser\'ed; and in Stone-house lake, that communicates with that arm of the sea, the boar came in with such impetuosity, that it drove every thing before it, tearing up the mud, sand, and banks, in a very shocking manner, and broke a large cable, by which the foot passage boat is drawn from side to side of the lake. You will please to observe, that it happened not here till about 4 p.m.; at Portsmouth, about 1 J a. m.; in Holland about 11 a. m.; at Kinsale, &c. in Ire- land not till 3 or 4 p. m. 14. On the Coast of Cornwall. By the Rev. fVilliam Borlase, of Ludgvan, A.M.,F.R.S. p. 373. A little after 1 o'clock in the afternoon, about half an hour after ebb, the sea was observed at the Mounts-bay pier to advance suddenly from the eastward. It continued to swell and rise for the space of 10 minutes; it then began to retire, running to the west and south-west, with a rapidity equal to that of a mill- stream descending to an undershot-wheel ; it ran so for about 1 0 minutes, till the water was 6 feet lower than when it began to retire. The sea then began to return, and in 10 minutes it was at the before-mentioned extraordinary height; in 10 minutes more it was sunk as before; and so it continued alternately to rise and fall between 5 and 6 feet, in the same space of time. The 1st and 2d fluxes and refluxes were not so violent at the Mount pier as the 3d and 4th, when the sea was rapid beyond expression, and the alterations continued in their full fury for 2 hours ; they then grew fainter gradually, and the whole commotion ceased about low water, 5\ hours after it began. Penzance pier lies 3 miles west of the Mount, and the reflux was first observed there 45 minutes after 2; the influx came on from the south-east, and south- south-east. Here the greatest rise was 8 feet, and the greatest violence of the agitation about 3 o'clock. Newlyn pier lies a mile west of Penzance. Here the flux was observed first, ss at the Mount, and came in from the southward (the eastern current being quite spent) nearly at the same time as at the Mount and Penzance, but in a manner somewhat different; it came on like a surge, or high crested wave, with a surprising noise. The first agitations were as violent as any ; and after a few advances and retreats at their greatest violence, in the same space of time as at the Mount, the sea became gradually quiet, after it had risen 10 feet perpendicular at least. This is near 6 feet more than at the Mount pier, and 2 feet more than at Penzance. The agitations of the sea at Moushole, an- other pier in this bay, did not materially differ from those at Newlyn. 654 PHILOSOPHICAL TRANSACTIONS. [anNO J 755. In the little harbour of Heyle, about 4 miles north of the Mount on the Severn sea, the agitation did not make its appearance till an hour and a little more after the ebb began, which must be full an hour later than with us. In this inland half-tide harbour it continued visible but an hour and half; the greatest flux was about the middle of that time, the surge being at that time 7 feet high; but in general it rose and fell but 2 feet only, owing probably to the force and quantity of water being broken in its advances into so retired a creek. At Swan- sea, in Wales, farther up in St. George's channel, where their ebb is later still than in Heyle, the agitation was proportionably later, and was not observed till after 1 hours ebb, near 3 quarters after 6. At Kingsale, in Ireland, more in- deed to the north of us, but more open to the Atlantic cx:ean than Swansea, and farther to the west, the agitation reached not a full hour after us, but above 1 hours sooner than at Swansea; all tending to show, that the force came from the south and south-west. What relations these little palpitations, or tremulous rebounds of the sea, had to the dreadful convulsions on the coasts of Spain and Portugal, whether they were the fainter parts of that deplorable shock at Lisbon, or the expiring efforts of some similar subterraneous strugglings of nature farther to the west, under the Atlantic ocean, will remain uncertain, till more facts and dates appear; but by the accounts from abroad, this first of November seems to have been a day of universal tremor to all the sea-coasts of the western parts of Europe. I would not be thought to suggest, sir, that a shock so far ofF as the coast of Spain could be so immense, as to propagate a motion of the water quite home to our shores. I should rather imagine, that there were several shocks, and some much nearer to us, but all perhaps from one and the same cause diffused in different portions, and permeating more contracted or dilated, but still com- municating passages; I should imagine, that this cause affected the seas and land, in proportion to its own force, and the superior or weaker resistance of the in- cumbent pressure ; that where it found the least resistance of all, there it found its vent, and the swell its cure. Many other similar accounts were also given, as observed both in the sea and inland lakes: as at Swansea, on the coasts of Norfolk and Lincolnshire, &c.; the lakes in Cumberland; a pond near Durham, at half past 10 o'clock; at Loch Ness, Loch Lomond, &c. in the north of Scotland, about 1 0 o'clock. It appears also, by communications sent from abroad, that the like agitations of the water were observed at the Hague, Ley den, Harlem, Amsterdam, Utrecht, Gouda, and Rotterdam, and also at Bois-le-Duc ; about 1 1 o'clock on the 1st of November; and likewise at Kingsale and Cork, in Ireland, between 2 and 3 o'clock. VOL. XLIX.] VHILOSOPHICAL TRANSACTIONS. 655 15. Of an Extraordinary Alteration in the Baths of Toplitz in Bohemia, on the \ St of November, 1755. By Father Joseph Steplin, of Prague, p. 3C)5. A report being brought that at Toplitz, a village famous for its baths, and Q Bohemian miles north-west from Prague, the source of these baths had under- gone some change, in order to know the truth of this. Father Steplin requested the president of the Supreme Royal Council to send him an exact account of it, in answer to the several questions which he proposed to him. By this means he procured the following: that in the year 762 those baths were discovered; from which time the principal spring had constantly thrown out the hot waters in the same quantity, and of the same quality. On the 1st of November, 1755, be- tween 11 and 12 in the morning, the chief spring cast forth such a quantity of water, that in the space of half an hour all the baths ran over. About half an hour before this vast increase of the water, the spring became turbid, and flowed muddy; and, having stopped entirely near a minute, broke forth again with pro- digious violence, driving before it a considerable quantity of a reddish oker, crocus martialis. After which it became clear, and flowed as pure as before; and continues still to do so; but it supplies more water than usual, and that hotter, and more impregnated with its medicinal quality. 16. Concerning the Agitation of the Waters, Nov. 1, 1755. By Mr. De Hondt, of the Hague, p. 396. We had at 1 1 o'clock a phenomenon, which astonished every body. In ab- solutely calm weather there was observed of a sudden so violent a motion in the water, that the ships were struck against each other, and broke the cables which fastened them. It was felt ^t the same time at the Hague, Leyden, Harlem, Amsterdam, Gouda, Utrecht, Rotterdam, and Bois-le-duc. At the Hague it was but slight; and no motion was felt in the ground. 17. On the same. By M. AUamond, Projessor of Philosophy at Leyden, and F.R.S. p. 397. Between half an hour after 10 and 11 in the morning, in some of the canals of this city, the water rose suddenly on the quay, situated on the south. It returned afterwards to its bed, and made several very sensible undulations, so that the boats were strongly agitated. The same kind of motion was perceived here in the tuns of water of 2 brewhouses, and in those of 3 brewhouses at Harlem. The branches of the Roman Catholic church at Rotterdam, which hung from long iron rods, made several oscillations. A tallow-chandler at the Hague was surprised to hear the clashing noise made by all the candles hung up in his shop. The accounts brought from Norway inform us, that the same observations were made there, almost at the same time. 656 PHILOSOPHICAL TRANSACTIONS. [anNO 1755. LIX, An Account of the Earthquake, Nov. 1, 1755, as fell in the Lead Mines in Derbyshire. Bij the Rev. Mr. Bullock, p. SQS. The following is an account of the earthquake, which happened at the lead mines on Eyam-edge in the peak of Derbyshire, on Saturday the 1st of Nov. 1755, about 11 o'clock in the forenoon. Francis Mason, the overseer, says, That he sat in a little room, about 40 yards from the mouth of one of the engine shafts. He felt one shock, which very sensibly raised him up in his chair, and caused several pieces of lime or plaster to drop from the sides of the room. In a field about 300 yards from the mines, there had happened a chasm or cleft on the surface of the earth, which was supposed to be made at the same time he felt the shock; its continuation from one end to the other, was near 150 yards, being parallel to the range of the vein on the north side: the depth of it was about 8 or 9 inches, and its dia- meter 4. Two miners say, that at the aforesaid time they were employed in carting, or drawing along the drifts the ore and other minerals to be raised up the shafts. The drift where they were working, is about 60 fathoms, or 120 yards deep, and the space of it from one end to the other upwards of 50 yards. They were suddenly surprised by a shock, which greatly terrified them. They durst not at- tempt to climb the shaft, lest that should be running in on them, but consulted what means to take for their safety. While they were thinking of some place of refuge, they were alarmed by a shock much more violent than the former ; which put them in such a consternation, that they both ran precipitately to the other end of the drift. Soon after they were again alarmed by a third shock; which, after an interval of about 4 or 5 minutes, was succeeded by a fourth ; and about the same space of time after, by a fifth ; none of which were so violent as the second. They heard after every shock a loud rymbling in the bowels of the earth, which continued for about half a minute, gradually decreasing, or appear- ing at a greater distance. They imagined, that the whole space of time, from the first shock to the last, was about 10 minutes. They remained about 10 mi- nutes in the mine after the last shock; when they thought it advisable to exa- mine the passages, and to get out of the mine, if possible. As they went along the drifts, they observed, that several pieces of minerals had dropped from the sides and roof, but all the shafts remained entire, without the least discomposure. The space of ground at the mines, wherein it was felt, was 960 yards, being all that was at that time in work. 1. Account of the Earthquake at Lisbon,* Nov. 1, 1755, in Ttvo Letters from Mr. JVolfall, Surgeon, p. 402. Since the beginning of the year 1750, we have had much less rain than has • This city suffered greatly by an earthquake in 1531. — Orig. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 657 ever been known in the memory of man, excepting the last spring : the summer has been cooler than usual, and for the last 40 clays, fine clear weather, but not remarkably so. On the first instant (Nov. 1 755,) about 40 minutes past g in the morning, was felt a most violent shock of an earthquake : it seemed to last about the 10th part of a minute, and then came down every church and con- vent in town, together with the King's palace, the magnificent opera-house, joining to it ; in short, there was not a large building in town that escaped. Of the dwelling houses, there might be about one-fourth of them that tumbled, which, at a very moderate computation, occasioned the loss of thirty thousand lives. The shocking sight of the dead bodies, with the shrieks and cries of those who were half buried in the ruins, are only known to those who were eye-witnesses. It far exceeds all description, for the fear and consternation was so great, that the most resolute person durst not stay a moment to remove a few stones off the friend he loved most, though many might have been saved by so doing : but nothing was thought of but self-preservation; getting into open places, and into the middle of streets, was the mot probable security. Such as were in the upper stories of houses, were in general more fortunate than those that at- tempted to escape by the doors ; for these were buried under the ruins with the greatest part of the foot-passengers : such as were in equipages escaped best, though their cattle and drivers suffered severely ; but those lost in houses and the streets, are very unequal in number to those that were buried in the ruins of churches ; for as it was a day of great devotion, and the time of celebrating mass, all the churches in the city were vastly crowded, and the number of churches here exceeds that of both London and Westminster; and as the steeples are built high, they mostly fell with the roof of the church, and the •tones are so large, that few escaped. Had the misery ended here, it might in some degree have admitted of re- dress ; for though lives could not be restored, yet the immense riches that were in the ruins, might in some part have been digged out : but the hopes of this are almost gone, for in about 2 hours after the shock, fires broke out in 3 different parts of the city, occasioned by the goods and the kitchen-fires being all jumbled together. About this time also the wind, from being perfectly calm, sprung up a fresh gale, which made the fire rage with such fury, that at the end of 3 days all the city was reduced to cinders. Indeed every element seemed to conspire to our destruction ; for soon after the shock, which was near high water, the tide rose 40 feet higher in an instant than was ever known, and as suddenly subsided. Had it not so done, the whole city must have been laid under water. As soon as we had time for recollection, nothing but death was present to our imaginations. For 1st, the apprehensions of a pestilence from the number of dead bodies, and the general confusion, and want of people t(» VOL. X. 4P . 658 ' PHILOSOPHICAL TRANSACTIONS. ■ [aNNO 1755. bury them, were very alarming : but the fire consumed them, and prevented that evil. 2d. The fears of a famine were very great ; for Lisbon is the store- house for corn to all the country, for 50 miles round : however, some of the corn- houses were happily saved, and though the 3 succeeding days to the earth- quake an ounce of bread was worth a pound of gold, yet afterwards bread became moderately plenty, and we were all happily relieved from our starving condition. The 3d great dread was, that the low villainous part of the people would take an advantage of the confusion, and murder and plunder those few who had saved any thing. This in some degree happened ; on which the King gave orders for gallows immediately to be placed all round the city ; and after about a hundred executions, among which were some English sailors, the evil stopped. We are still in a state of the greatest uncertainty and confusion, for we have had in all 22 different shocks since the first, but none so violent as to bring any houses down in the out-skirts of the town, that escaped the first shock ; but nobody yet ventures to lie in houses ; and though we are in general exposed to the open sky for want of materials to make tents, and though rain has fallen several nights past, yet the most delicate tender people suffer their difficulties with as little inconvenience as the most robust and healthy. Every thing is yet with us in the greatest confusion imaginable : we have neither clothes nor con- veniences, nor money to send for them to other countries. All Europe is deeply concerned in the immense riches and merchandises that are lost, but none so much as our own nation, who have lost every thing they had here. Few English lives have been lost in comparison of other nations, but great numbers wounded ; and though we have 3 English surgeons here, but unfortunately without either instruments, bandages, or dressings, to relieve them. Two days after the first shock, orders were given to dig for the bodies, and a great many have been taken up and recovered. Mr. W. lodged in a house where there were 38 in- habitants, and only 4 saved. In the city prison 800 were lost. 1200 in the ge- neral hospital,' a great number of convents of 400 in each lost ; the Spanish ambassador with 35 servants. It fortunately happened, that the King and the Royal Family were at Belime, a palace about a league out of town. The palace in town tumbled the first shock, but the natives insist that the inquisition was the first building that fell down. The shock has been felt all over the kingdom, but along the se -side more particularly. Faro, St. Ubals, and some of the large trading towns are, if possible, in worse situation than here ; though the city of Porto has quite escaped. It is possible, that the cause of all these misfortunes came from under the western ocean ; for a captain of a ship, a very sensible man, told him that he was 50 leagues off at at sea ; that the shock was there so violent as greatly to injure the deck of his ship ; it occasioned him to think that he had mistaken VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. Q^g his reckoning, and struck, upon a rock, and they instantly hawled out their long- boat to save themselves, but happily brought the ship, though much injured, into this harbour. The shocks lasted between 5 and 7 minutes. The very first shock was ex- tremely short, but then it was as quick as lightning succeeded by two others, which, in the general way of speaking, are mentioned all together as only one shock. About 12 o'clock we had a second shock. Mr. W. was then in the Terra do Paqo, or King's palace-yard, and had an opportunity of seeing the walls of several houses that were standing, open from top to bottom, more than a quarter of a }ard, yet close again so exactly as to leave no sio-ns of injury. 3. Abstract of Two Letters, by John Mendes Saccheli, M.D., F.R.S. dated from the Fields of Lisbon, on the T th of November, and the \st of Decem- ber, 1755. p. 409. The day before the fatal earthquake the atmosphere, and light of the sun, had the appearance of clouds and notable ofl'uscation, and more strong and vi- sible at the actual time of the great shock, which was by undulation, and lasted from 6 to 8 minutes. It ruined not only this populous city, but all the southern part of the country of Estremadura, and a great part of the kingdom of Al- garve. The earth opened in fissures in several parts, but neither fire nor visible smoke came out of it. The water in the sea rose several times, and in a few minutes made 3 fluxes and refluxes, rising above the greatest spring-tides 2 spawns, or 1 5 English feet. 4. Abstract of a Letter from Mr. J. Latham, dated at Zsu-queira, Dec. 11 1755, to his Uncle in London, p. 411. I was on the river on Saturday the 1 st of November, with a gentleman going to a village 3 miles off. In a quarter of an hour the boat made a noise as if on the shore or landing. About 4 or 5 minutes after, the boat made a noise as before, which was another shake. We saw the houses tumble down on both sides of the river. In Lisbon, a convent on a high hill fronting the river, the most part of it came down, a great many were killed and buried in the ruins ; many tumbled neck and heels in the water, others ran down to the river, up to their middle and necks. A strong northerly wind blew from shore, which covered the water with dust, and in our boat we could scarcely see one another \ and it entirely hid the sun from us for some time. The wind soon dispersed the dust, the shaking seemed over. In about three quarters of an hour we came to the village, where we were called ashore, and met several gentlemen, who came, out of the city on horse-back, but so frighted, that they did not know what was the matter. In a quarter of an hour after our landing, the village was alarmed with another shake. We got down to our boat ; in a moment the river rose so 4p2 GQO PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. high as obliged us to take to our heels, and run for our lives into the fields and high ground, the water flowing across the road, which, from the low tide, was above a quarter of a mile ; the ships were whirled about, and several people taken into the water, others driven ashore and dashed to pieces. From the high grounds we could see the sea at about a mile's distance come rushing in like a torrent, though against wind and tide. A fine new stone quay in Lisbon, where the merchants land their goods, where at that time about 3 thousand people were got out for safety, was turned bottom upwards, and every one lost ; nor did so much as a single body appear afterwards. It being a holy-day, great numbers of the natives being at their devotion in convents and churches, whose large buildings suffered most, it is computed about 6o thousand souls, and a hundred and odd of the foreigners, and all sorts of cattle perished. The reli gious houses being illuminated with wax-lights, and the images dressed, by the shakes were set on fire by night, in several places, and by Monday morning en- tirely consumed, with the rich furniture of convents, nuimeries, and nobility's houses, and all the merchants and tradesmen's goods, besides jewels, gold, plate, and coined money. There have been a great many shakes by nights and days : even on the 8th of December was felt a strong one : it was much more violent in some places than others. The ground was opened ; in some places you might put your hand down broad-ways, and not feel the bottom with a long stick. A sea port, called St. Ubal's, was entirely swallowed up, people and all. 5. Observations made at Colares,* on the Earthquake at Lisbon, of the 1st oj" November 1755, by Mr. Stoqueler, Consul of Hamburg, p. 413. The 1st of November, the day broke with a serene sky, the wind continuing at east; but about Q o'clock the sun became dim, and about half an hour after we began to hear a rumbling noise, like that of carriages, which increased to such a degree as to equal the noise of the loudest cannon ; and immediately we felt the first shock, which was succeeded by a 2d and 3d ; on which, as also on the fourth, were seen several light flames of fire issuing from the sides of the mountains, resembling what is observed on the kindling of charcoal. In the spot on which he remained till the 3d shock was over, he observed the walls to move from east to west. In the afternoon of the 3 1 st of October, the water of a fountain was greatly decreased : on the morning of the 1 st of November it ran very muddy, and after the earthquake it returned to its usual state, both in quantity and clear- ness. Some fountains, after the earthquake, ran muddy, some decreased, others increased, others were dried up; and one, that with the earthquake was • It is about 20 miles from Lisbon, and lies behind the rock, about 2 miles from the 0ea. — Orig. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 66l dried up entirely, returned 2 days after to its usual state. In some places where there was no water, springs burst forth, which continued to run. On the spot of Varge, and river of Macaas, at the time of the earthquake, many springs of water burst forth, and some spouted to the height of 25 palms,* throwing up sand of various colours, which remained on the ground. On the hills, numbers of rocks were split, and there were several rents in the ground, but none con- siderable. On the coast pieces of rock fell, some of them very large, and in the sea sundry rocks were broken : the most noted are those called by the sailors Sarithoes, or Biturecras, of which one was only broken off at the summit, the other all to pieces. Between these rocks and the main, the coasting vessels sailed at low water ; and now you may go to them at low water, without wetting your feet. From the rock called Pedra de Alvidrar, a kind of parapet was broke off, which issued from its foundation in the sea. In a swamp or lake, which received a good deal of water in winter, and was not dry in summer, the earth rose ; for there is now scarcely the appearance of a hollow, which was before to the depth of six or seven palms ; it now remains even with the adjacent ground. In other places, by the change of the currents it appears that the earth was moved, so that some spots are more elevated, others more depressed than before. 6. Concerning ihe Earthquake at Oporto in Portugal, Nov. 1, 1755. By a Letter Jrom that Place, p. 418. Saturday Nov. 1st, we had such a terrible earthquake here, that we were afraid of being swallowed up alive, though it has done but very little damage. It began about half an hour past Q o'clock in the morning, like thunder, or rather the rattling of a coach over stones , and my own house, as well as most other people's, during the first shock, which was a very terrible one indeed, was just as if in a convulsion, which lasted 7 or 8 minutes, and every thing shook and rattled in it all the time, as if it was coming down ; which frightened people so much, that a great many ran into the streets, where I plainly saw the earth heave up. At 6 o'clock at night there was another great shock. The river also rose and fell surprizingly every quarter of an hour, for upwards of 4 hours at least, 4 or 5 feet, and sometimes more ; and some saw the river in some places open, and throw out a vast deal of wind, which was very terrifying. Abstract of Two Letters to Mr. Plummer, Merchant in London, from Oporto, concerning the Earlhquakefelt there, p. 419. This morning, Nov. 1, 1755, between 9 and 10 o'clock, this city was alarmed with the terrible shock of an earthquake, which continued violently for 5 or 6 minutes, but has done no further damage than the overturning some pedestals * The Portuguese palm is about 9 inches. — Orig. 602 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. from the tops of some churches, and splitting the walls of some old houses. The shock was perceived in the river, among the shipping, by a sudden flux and reflux of the tide, but no damage was done. During the time of the earthquake, and indeed preceding it, was heard a hollow dreadful noise. Abstract of a Letter from Madrid to the Spanish Consul in London, p. 423. Nov. I, soon after 10 o'clock, there was very sensibly felt a great earthquake: according to the common opinion, it lasted 5 or 6 minutes. Every one at first thought that they were seized with a swimming in their heads ; and afterwards that their houses were falling. The same happened in the churches, so that the people trod each other under foot in getting out ; and those who observed it in the towers were very much frightened, thinking that they were tumbling to the ground. It was not felt by those who were in their coaches, and very little by those who walked on foot. Of the Earthquake at Cadiz, Nov. 1, 1755, in a Letter from Mr. Benjamin Betvich, Merchant there, p. 424. Nov. 1, just before 10, the whole town was shaken with a violent earthquake, which lasted above 3-i- minutes. The water in the cisterns, which are under- ground, washed backward and forward, so as to make a great froth upon it. Every body ran out of the houses and churches, in a terrible consternation, but no damage was done, as all the buildings here are excessively strong. An hour after, looking out to sea, we saw a wave coming at 8 miles distance, which was at least 6o feet higher than common. Every body began to tremble ; the cen- tinels left their posts, and well they did : it came against the west part of the town, which is very rocky ; the rocks abated a great deal of its force. At last it came upon the walls, and beat in the breast-work, and carried pieces of 8 or 1 0 tons weight, 40 and 50 yards from the wall, and carried away the sand and walls, but left the houses standing, so that only 2 or 3 persons were drowned. Every one now thought the town would be swallowed up ; for though this was run off^, yet with glasses we saw more coming. When the wave was gone, some parts, that are deep at low water, were quite dry, for the water retired with the same violence that it came with. These waves came in this manner 4 or 5 times, but with less force each time ; and about one the sea became more calm, but was still in a boiling motion. Every thing was washed off" the mole. The bay was full of barrels, and boats, and timber ; but no damage was done to the shipping. The walls have suffered very much. Some of the towns about us have suffered a great deal more than we, by the falling of houses and towers. Of the Earthquake at Cadiz. By Don Antonio d'Ulloa, F.R.S. p. 427. Nov. 1 , we had here an earthquake, the violence of which was not inferior to that which swallowed up Lima and Callao, in Peru, towards the end of October 1746. It happened in very fine weather, at 3 minutes after Q in the morning. VOL. XHX.J PHILOSOPHICAL TRANSACTIONS. 66H, and continued 5 minutes, and consequently near twice as long as that of Peru, the duration of which was only 3 minutes. If every thing was not destroyed here, it seems particularly owing to the solidity of the buildings. The inhabit- ants had scarcely begun to recover from their first terror, when they saw them- selves plunged into new alarms. At 10 minutes after 1 1 they saw rolling towards the city a tide of the sea, which passed over the parapet of 6o feet above the ordinary level of the water. At 30 minutes after 1 1 came a 2d tide ; and these 2 were followed by 4 others of the same kind, at 50 minutes after 11, at 12. o'clock 30 minutes; 1 o'clock 10 minutes; and 1 o'clock 50 minutes. The tides continued, with some intervals, till the evening, but lessening. They have ruined 100 toises of the rampart; part of which of 3 toises length, and of their whole thickness, were carried by the torrent above 50 paces. A great number of persons perished on the causey, which leads to the isle of Lesu. Seville has been greatly damaged. St. Lucar and Cheres have likewise suffered much ; and Conel is said to be entirely destroyed. jin Account of the Earthquakes that happened in Barbary, inclosed in a Letter from General Fowke, Governor of Gibraltar. Communicated by Philip Lord Viscount Royston, F.R.S. p. 428. AtTetuan the earthquake began, the 1 st of November, at 10 in the morn- ing, and lasted between 7 .and 8 minutes ; during which space the shock was repeated 3 different times, with such violence, that it was feared the. whole city would fall down ; but the only damage that resulted was the opening or parting of some of the walls of sundry houses. It was likewise observed that the waters of the river Chico, on the other side of the city, and those of a fountain, ap- peared very red. At Tangier, the earthquake began about the same time, but lasted longer than at Tetuan ; the trembling of the houses, mosques, &c. was great, and a large promontory of an old building near the city gate, after 3 shocks, fell down to the ground, by which 5 shops were demolished ; the sea came up to the very walls, a thing never seen before, and went down directly with the same rapidity as it came up, as far as the place where the large vessels anchor in the bay, leav- ing upon the mole a great quantity of sand and fish. These commotions of the sea were repeated 18 times, and continued till 6 in the evening, though not with such violence as at the first time. The fountains were dried up, so that there was no water to be had till night : and as to the shore-side, the waters came up half a league inland. At Arzila, it happened about the same time, but the damage was not great. At the coming up of the sea 7 Moors, who were out of the town walls, were drowned ; and the waters came in through one of the city gates very far. The water came up with such impetuosity, that it lifted up a vessel in the bay ■©(it PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. which, at the water s falling down to its centre again, fell down with such a force upon the land, that it was broke to pieces ; and a boat was found at the distance of 2 musket-shots within land from the sea. At Salle, there happened very great damage, several houses having fallen down. The waters came up with such rapidity, that they came into the city, and at their falling down, great quantities of fish were found in the streets, and many persons were drowned: 2 ferry-boats overset in the river, and all the people on board were also drowned; and a great number of camels, that were just then going for Morocco, were carried away by the waters. At Fez, vast numbers of houses fell down, and a great many people were buried under the ruins. At the Scloges, a place where the Barbai-ians live, not far from Fez, a mountain broke open, and a stream issued out as red as blood. At Mequinez, a vast number of houses fell down, and a great many people of both sexes were buried under their ruins ; the convent of the Franciscan friars fell down to the ground, but the friars were saved. At SafFe, several houses fell down, and the sea came up as far as the great mosque, which is at a great distance from the sea. At Morocco, by the falling down of a great number of houses many people lost their lives ; and about 8 leagues from this city, the earth opened, and swal- lowed up a village, with all the inhabitants, (who were known by the name of the sons of Busunba) to the number of about 8 or 10,000 persons, with their cattle of all sorts, as camels, horses, horned cattle, &c. and soon after the earth was closed again, in the same manner as it was before. At Fez and Mequinez, on the 18th of November there happened another earthquake, which was more violent than the first, and lasted till break of day the 19th; during which time great numbers of houses fell down at Fez; many people of both sexes were buried under their ruins ; and as to Mequinez, there are but few houses left standing. The people killed by the falling of the houses, besides the wounded, are numberless ; and in the part of the town called the Jews' Habitation, only 8 persons were saved. At Saijon Hills, one of the hills was rent in two ; one side of which fell on a large town, where there was the famous sanctuary of their prophet, known by the name of Mulay Teris ; and the other side of the said hill fell down on an- other large town, and both towns and the inhabitants were all buried under it. The famous city of Tasso was wholly swallowed up ; no remains left. This last earthquake was likewise felt at Tetuan and Tangier, but without any other damage than that the fountains of Tangier were dried up for 24 hours. Of the Earthquake in t/ie Island of Madeira, Nov. 1, 1755, in a Letter from Dr. Tho. Heberden, to his Brother Dr. Wm. Heberden, F.R.S. p. 432. Nov. 1, 1755, in the city of Funchai, on the island of Madeira, at half an VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 605 hour past Q o'clock in the morning, was perceived a shock of an earthquake. The first notice was a rumbling noise in the air, like that of empty carriages passing hastily over a stone pavement ; immediately the floor moved with a tre- mulous motion, vibrating very quickly; the windows rattled, and the whole house seemed to shake. The shock lasted a full minute ; during which the vi- brations, though continual, abated and increased twice very sensibly, in point of force. The noise in the air, which had preceded the shock, continued to ac- company it ; and lasted some seconds after the motion of the earth had entirely ceased ; dying away like a peal of distant thunder rolling through the air. The direction of the shock seemed to be from east to west. About an hour and half after the shock had ceased, the sea, which was quite calm, was observed to retire suddenly some paces, anrl rising with a great swell, without the least noise, as suddenly advancing, overflowed the shore, and en- tered into the city. It rose full 1 5 feet perpendicular above high water mark, though the tide, which ebbs and flows here 7 feet, was then at half ebb. The water immediately receded again, and after having fluctuated 4 or 5 times be- tween high and low water mark, the undulations continually decreasing, it sub- sided, and the sea remained calm. In the northern part of this island the inundation has been more violent, the sea there retiring at first above 100 paces, and suddenly returning, overflowed the shore, destroying or damaging several houses and cottages, forcing open doors, and breaking down the walls of several stores or magazines, and carrying away in its recess a considerable quantity of grain, &c. Great quantities of fish were left on the shore, and in the streets of the village of Machico. All this has been the effect of one sole undulation of the sea, it never flowing afterward so high as high water mark ; though it continued fluctuating much longer there, before it subsided, than here at Funchal,, as the fluctuation and swell was much greater here than it had been farther to the westward, where in some places it has been hardly, if at all, perceptible. yinother Account of the same Earthquake at Madeira. By Mr. Charles Chambers, p. 435. This account contains no other particulars than the foregoing. Of the late Earthquakes of Nov. 1, and Dec. Q, 1755, as felt at Neufchalel in Swisserland. By Mans. De Paulravers, F. R. S. p. 436. The dreadful earthquake of the 1st of November last has been perceived even in this country, though very faintly. It turned some of our rivers suddenly muddy, without any rain, and swelled our lake of Neufchatel to the height of near 2 feet above its natural level, for the space of a few hours. The Qth of this month (Dec.) we felt a much more severe sliock of an earth- quake. It happened a little before 3 o'clock in the afternoon,, with a vibratory VOL. X. 4 Q 66(5 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. motion from west to east ; another from east to west, and a third from west to east again. Some chimnies fell in at Cudrefin ; the bell in the tower at Morat rung 2 strokes. The shock was severer in lofty places than it was in low grounds. The lake of Morat, immediately after the earthquake, sunk 3 inches, and re- mains still in the same depression. The same earthquake was felt the same day, at the same hour, at Basil, Berne, Fribourg, Geneva, and all over Swisserland ; as likewise at Besanqon in France. Of the Earthquake felt at Geneva, Dec. Q, 1755. Bij Mons. Trembley. p. 438. The earthquake of Nov. 1, was felt at Lyons. It is said that the waters re- tired for some moments at the end of the lake of Geneva ; and that a motion was observed in those of the lake of Zurich. On the Qth of this month, (Dec.) a little before half an hour after 2 in the afternoon, in very fine and very calm weather, there was felt here in all the houses in general a very great shock of an earthquake; but it did no damage. The motion was particularly i-emarked in looking-glasses and windows. Those who were sitting perceived that their chairs shook; and many thought that they were going to fall. The sick felt the motion in their beds. The bells in the rooms of several houses rang. The bell of the clock in the tower of the isle of Rhone rung several times. The motion was felt even on the ground floor of houses. It was felt at Nion, Morges, Lausanne, Berne, Zurich, and perhaps more strongly than here. Three shocks were in fact felt within the space of about a minute. During the first a noise was heard like that of a cart passing over a pavement. Of the Earthquake felt at Boston in New- England, Nov. 18, 1755. Communi- caied by John Hyde, Esq. F. R. S. p. 439. Tuesday, Nov, 18, 1755, about half an hour past 4 in the morning, Mr. H. was awaked by the shaking of his bed and the house ; the cause of which he im mediately concluded could be nothing but an earthquake, having experienced one before. The trembling continued about 2 minutes. Near 100 chimnies are levelled with the roofs of the houses : many more, probably not fewer than 1 2 or or 1500 are shattered, and thrown down in part; so that in some places, espe- cially on the low loose ground, made by encroachments on the harbour, the streets are almost covered with the bricks that have fallen. Some chimnies, though not thrown down, are dislocated, or broken several feet from the top, and partly turned round, as on a swivel; some are shoved on one side horizon- tally, jutting over, and just nodding to their fall : the gable ends of several brick buildings, perhaps of 12 or 15, are thrown down, and the roofs of some houses are quite broken in by the fall of the chimnies : some pumps suddenly dried up ; the convulsions of the earth having choaked the springs that supplied them, or altered their course. Many clocks were also stopped by being so violently agitated. VOL. XLIX."] PHILOSOPHICAL TRANSACTIONS. (5^7 Of the Earthquake felt in New York, November 18, 1735, in a Letter from Cadwallader Colden, Esq. p. 443. A few minutes past 4 in the morning, Mr. C. was awaked with the shock of the earthquake. He plainly heard the noise like that of carts on pavements, going to the eastward, with now and then a noise like the explosion of a great gun at a distance. It was felt about 4 o'clock at Philadelphia, and half after 4 at Boston, and was more violent to the eastward than the westward) and there was an eruption at a place called Scituate, about 20 or 30 miles to the south- ward of Boston. The summer and autumn had been unusually dry for some days before the earthquake, though the sky was perfectly calm and serene, the air was so light, that the smoke of the town by falling down was offensive to our eyes, as we walked the streets. In the last remarkable earthquake, which hap- pened about 17 years before, and nearly at the same time of the year, the wea- ther preceding it was much the same as now, attended with the falling of the smoke in the towni. Of the Earthquake felt in Pennsylvania, Nov. 18, 1755, in a Letter to Mr. Peter Coilinson, F. R. S. p. 444. Abour 4 o'clock this province was pretty generally alarmed with the shock of an earthquake. It gradually increased for 1 minute to such a degree as to open the chamber door, by drawing the bolt of the lock out of the staple. Some people thought they felt its continuance 5 or 6 minutes, but the writer thinks it did not exceed 1, nor was it less. He felt the shock of the 1 earthquakes in England ; but they were little in comparison to this. LX. Of Four Undescribed Fishes of Aleppo. By Alex. Russel, * M. D. p. 445. Of these fishes Dr. Russel brought the drawings and descriptions from Aleppo. •Alexander Russel, m.d. was born in the city of Edinburgh about the year IZl*; where hi» father practised the profession of the law with great reputation. After the usual course of grammati- cal study in the High School at Edinburgh, and afterwards in the University, he was placed with his uncle, an eminent physician in the same city. In the years 1732, 3, and 4, he attended the lectures of the various professors, and having finished his studies, he settled about the year 1740, at the city of Aleppo, where he was greatly esteemed by the Englisli factory. He acquired great cele- brity in his profession, and was frequently consulted, not only by the Greek, Armenian, and Jewish inhabitants of that region, but even by the Turks themselves, who are said to have held him in high esteem, and to have placed great confidence in his opinion. In 1755 he returned to Britiin, and settled in London, where he composed his well-known work the History of Aleppo, of which a second edition has lately been published under the care of his brother the late Dr. Patrick Russel, author of the splendid work on Indian Serpents and Fishes. To Dr. Alexander Russel we owe the introduction of the true scammony, as well as tliat liighly elegant shrub the arbutus andrachne into the Botanic Gardens of England. About 1739 he was chosen physician to St. Thomas's Hospital, and was also elected a F.a.8. He attained a verj- considerable degree of eminence in his profession, and maintained a great integrity of character. He died Nov. 28, in the year 176"8. 4Q 2 ()QS PHILOSOPHICAL TRANSACTIONS. [aNNO J 755. Fig. 11 and 14, pi. 15, seem to be quite new genera; and 12 and 13, though they belong to the same genus with the mystus, described by Gronovius in his Mus. Ichthyologic. p. 34, N° 83, and p. 35, N° 84, yet are species of that fish which has not hitherto been described. The fish, fig. 11,* resembles much in shape the Silurus Rondeletii, and has no scales. Its length, from the nose to the tip of the tail, is 20 inches ; weight 20 oz. ; but they are of different sizes. The head and back are of a black, colour. The lateral line runs quite from the head to the tail, on the middle of the side ; below which, to the belly, the colour gradually changes into a dark purple ; of the same colour is the under part of the head. The head is flat, and near 5 inches in length. The body roundish, till within a few inches of the tail, where it grows flat. The mouth is not so large in proportion as that of the Silurus; it has no tongue, and the structure of the mouth and palate agree exactly with the description of that fish. From the edge of the nostril on each side arises a small cirrus; and from the angles of the mouth 2 others, that are stronger, and twice as long. On the lower lip are 4 more, the 2 external being the longest. The eyes are situated near the corner of the mouth, close on the edge of the upper jaw. The branchiae are 4 on each side, and all of them have a double row of sharp points, like the teeth of a comb. It has 2 fins, situated near the bran- chiae, consisting of 7 radii, to the interior part of which is joined a pretty strong prickly bone : about an inch above the anus are 2 smaller fins. A long fin ex- tends from a little way under the anus to the tail, as another of the same kind does from the neck all along the back : neither of these fins join with the tail, which is round at the tip, and composed of about 22 feathers. It is found in the river Orontes, and in some stagnant waters near it. The markets of Aleppo are plentifully supplied with it, from the month of November till the beginning of March. The flesh is red like beef, and of a rank taste ; and, though for want of better, eaten much by the people, yet is esteemed unwholesome. The name it usually goes by is semack al aswad, which signifies the black fish. Its proper name however among the natives is siloor. The fish fig. 12,-|- is about 4 inches long. The head is large and flat, the body oblong and compressedr Its colour is mostly of a dark silver. The eyes are large and protuberant. From the lower jaw arise 4 cirri ; the longer measure one inch, the shorter 2 thirds of an inch. From the upper jaw arise 2 longer, each measuring 2-i- inches, of a firmer texture than either those of the lower jaw, or 2 other small ones placed just by the nostrils. Between the 2 long cirri are 2 small tubuli. The whole of the cirri are of a white colour, excepting the 2 longest, which are of a darkish colour, like the upper part of the head. The • Stiurus anguilkrit. Lion. + Silurus com. Lien. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 66Q fins are 8 in number. Tsvo by the gills, each furnished with a strong saw-like bone. Two small ones near the anus. One of 8 radii, situated half-way be- tween the anus and the tail. One consisting of 7 radii on the back. Another fin, of a membranous and fleshy texture, arises from the middle of the back, and is continued all along to the tail. The tail is forked. It is found in the river Coic at Aleppo, where the fish in general are extremely small, in propor- tion to those of the same kinds found in other rivers, probably owing to the assi- duity of the fishermen. It is called by the natives, zakzuk. Fig. 13 represents a fish, which in its general form somewhat resembles the above. It is in length 3 inches. The head is rather flatter ; the mouth has a more inferior situation, and is in proportion larger than that of the former fish ; the eyes much smaller. The cirri, situated as in the other, are 8 in number, but much shorter those that rise from the upper jaw (being the longest) mea- suring only one inch ; they are also flatter at their origin. They both agree in the number of their fins ; neither has the saw-like bone in the fin of the back, but only in those near the gills. The fleshy fin of the back is much smallei" than in the zakzuk, and rises at a much greater distance from the back fin. The colour is a pale silver marbled with grey ; particularly the lower part of the fins and tail. The 2 larger cirri likewise marbled, the others white. These 2 fishes (fig. 12, 13) have no scales, and the palate and other structure of the in- side of the mouth is like that of the silurus. This fish is also from the river Coic. The fish fig. 14* has, on a slight view, so much the appearance of an eel, and, except its not being so fat, eats so like that fish, that though it is much oftener brought to the tables of the Europeans at Aleppo than any other fish found in the river Coic, it has never been suspected of being any ways different from the common eel ; and yet on examination it will be found of quite another genus. The head is long and small. The extremity of the upper jaw runs out to a narrow point, like the bill of a bird ; on each side of which, a little distant from the extreme point, are 2 tubuli, or processes. As in the common eel, there are 2 fins at the gills. From the occiput, all along the ridge of the back, small prickles are placed at little distances, resembling the teeth of a saw ; these termi- nate at the origin of a membranous fin, rising about 4 inches from the tail, and is continued, as in the eel, along the lower part of the belly to the anus, at which place are also found 2 or 3 prickles. The colour of the head and back is blackish, variegated with dark yellow spots. The lower belly white, changing gradually into a yellowish cast. The fin of the lower belly, near the anus, is yellow: the other half spotted with black. The length of the fish describetl was 11 inches. • Ophidium Maslacembalus, (Gen. Zool.) 670 PHILOSOPHICAL TRANSACTIONS. [aNNO 1/55. LXI. Of a Curimis, Fleshy, Coral-like Substance.* By Dr. John jllbert Schlosser, M.D., F.R.S. ffith some Observations on it, by Mr. John Ellis, F.R.S. p. 449. Having hired some fishermen to dredge, to examine the small English coral, or corallium nostras of Ray's Synopsis, recent in the microscope ; the first time they hauled in the dredge, the Dr. discovered a most extraordinary sea-produc tion surrounding the stem of an old fucus teres : it was of a hardish, but fleshy substance, and more than an inch thick, of a light brown or ash-colour, the whole surface covered over with bright yellow shining and star-like bodies, which induced him to believe it to be an undescribed species of alcyonium. He put it immediately into a bucket of sea-water, expecting every moment that the polypes, which he thought lodged in those little stars, would extend and show themselves, like those of the alcyonium, N" 2 of Ray's Synopsis, commonly called dead man's hand , but after more than half an hour's fixed attention, the vessel lying very quiet all the time, he did not perceive the least appearance of any polypes : on which he brought them to shore in the sea-water, and then, by means of the microscope, discovered every one of those stars to be a true animal, and much more beautiful than any polype, but quite of a different structure. Every one . of those stars is composed of many thin hollow radii, of a pear-shape form, from 5 to 12 or more in number, all united intimately at their smaller end : every radius appears broad at the extreme part from the centre, and a little convex in the middle of this raised broad part. When the animal is alive, there appears a small circular hole, which contracts and opens frequently. All the i-adii are of this structure ; but their common centre, which is formed by a combination of all the small converging extremities, exhibits an opening of a circular, oval, or oblong figure, forming a kind of rising rim like a cup, which, when the animal is alive and at rest, contracts and expands itself to many different degrees, with great alertness and velocity, though sometimes it remains a great while expanded, or contracted. In all these holes, the central large one, as well as the smaller ones, which last he takes to be the mouths of the animal, he could not perceive any ten taenia or claws on the outside ; but by looking into them very narrowly, he saw something like very tender little fibres moving at the bottom of their in- sides. By comparing and examining all the various pieces he had collected of this fleshy substance, with its shining stars, he observed that the size and colour, as well as the very figure of these stars, varied greatly ; but the structure of the leaf-like radii, and that of their mouths, and their motions, were perfectly the same in every one individual. Many of these bodies he found so thick and large, * The substance here described belongs to the genus alcyonium, and is the Alcyonium Schlosseri of Linneus. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. §7 1 as to resemble the great branched madrepora coral, especially as they are gene- rally to be met with covering and inclosing the stem and branches of this stiff, ramose fucus. Thus far Dr. Schlosser. Mr. John Ellis adds the following : Fig. A, pi. 16, expresses this alcyonium, surrounding the stem and branches of a fucus. I have called it alcyonium carnosum asteriscis, radiis obtusis, ornatum. Fig. b, part of a leaf of the common alga, or sea-grass, with 4 of these starry figures on it. Fig. c, one of the stars magnified. Fig. d repre- sents the fucus, on which it grows, which I cannot find any where de- scribed. I have entitled it, in my collection of English fucuses, by the follow- ing descriptive name, fucus teres frutescens, germinibus arborum gemmas fructiferas referentibus. I have had an opportunity lately of examining this curious, fleshy, coral-like figure in the microscope, and find that all the interstices between the stars are filled with eggs of different sizes, each adhering by one end to a very fine capil- lary filament. The smallest eggs are globular, and as they advance in size, they change to an oval figure ; whence they assume the shape of one of the radii of the stars. In several of these stars I have observed a smaller radius, as it were, endeavouring to get into the circle ; and notwithstanding their seeming connec- tion in the centre as one animal, I believe I shall soon be able to show you, in a drawing from the microscope, that each radius is a distinct animal by itself. t LXII. Two Singular Cases of Diseased Knee-joints Successfolly Treated. The first by Topical Applications ; the second by Operation. By Mr. Joseph Warner, F.R.S. p. 452. The species of tumors here meant, are those which are distinguished by the name of hydrops articuli, or the dropsy of the joint; of which Mr. W, observes, there are 2 different kinds. The one where the disease is situated in the mem- brana adiposa, and neighbouring parts on this side the capsular ligament. The other is that species of disease, where the fluid is contained within the capsular ligament, between the extremities of the thigh-bone, and the largest bone of the leg. The first species of tumor may be distinguished from the 2d by the touch ; from the appearance of the tumor of the first kind, which is pale and uniform ; from a want of fluctuation, and from the little or no pain attending it. The repeated use, for some weeks, of emollient fomentations, mercurial frictions, and gentle purges, has often been known to remove this disorder. At other times it has been found, that these applications have had little or no effect, but that the disease has given way to, and been totally removed by the use of perpetual blisters to the part affected ; which should, in most instances, be con- tinued for several weeks. At other times Mr. W. has known the Pisselaeon In- 6/4 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. dicum, in English called the Barbadoes tar, to have so good an effect, by being applied every day to the joint for some weeks, even after every other remedy had failed, as to cure such a disorder of the kee-joint, as had hitherto been judged desperate : in which case there plainly appeared to be an enlargement of the bones, as well as a very considerable one of the integuments, and of the ten- dinous and ligamentous parts, but without any apparent inflammation. In this instance no extravasated fluid could be discovered ; however, there was an im- mobility of the joint, and a considerable contraction of the hamstrings. The pain was extremely great, which the patient described as shooting through the ligaments of the joint, the knee-pan, the extremities of the thigh-bone, and those of the leg. He had a severe symptomatic fever, which had been of many weeks continuance, by which he was become greatly emaciated. The reason for Mr. W.'s giving so particular an account of the circumstances attending this fact, proceeded from his desire of recommending a trial of the same remedy, in the like cases ; which, as far as he could judge from his own experience, might always be safely done where there was no degree of inflammation already formed on the integuments. The 2d species of hydrops articuli, or that where the extravasated fluid is con- tained within the capsular ligament, may be distinguished from the first, from its deep situation ; from the fluctuation which is felt on patting the knee on one side, while the other hand is held immoveably on the opposite side ; from the degree of pain arising from the distension, which the capsular ligament suffers in consequence of its contents ; from the incapacity of bending the joint ; and from the circumstance of its being attended with no general complaints of body ^s well as from the sudden enlargement of the tumor ; on the increase of which depends the degree of uneasiness in the part. This is very far from being the case in that kind of disease called the spina ventosa, which arises originally from the medulla and bone itself being diseased ; whence proceed grievous pricking and throbbing pains, that usually come on previously to any visible enlargement of the part affected, or any discoverable quantity of fluid deposited in the joint ; the difference of which symptoms resulting from the different diseases, is seen from the case which he describes, when it was judged necessary to cut more than once through the capsular ligament, in order to evacuate its contained extra- vasated fluid ; which, contrary to the commonly received opinion of wounds of the ligaments being attended with certain destruction to the limb, should always be done under the like bad circumstances, in reasonable expectation of removing a complaint, which totally disables the patient, and too frequently terminates in the loss of the limb when neglected. And Mr. W. was the more inclined to recommend this practice, as he was convinced that this disease is out of the reach of such applications, as are of service in other diseases of these parts, VOL. XLIX.J PHILOSOPHICAL TRANSACTIONS. 673 whose situation is more superficial ; that is, on this side the ligament, in which is contained the synovia. [Then follows a detail of the case, the insertion of which in these Abridge- ments was deemed unnecessary, after the preceding observations, and account of the successful result of the operation of cutting through the capsular li- gament.] LXIIL Extract of a Letter from Mr. William Pye, dated Manilla, Oct. 1st, 1754, giving some Account of that Place, p. 458. Manilla is one of the largest of the Philippine islands, and the city is much larger than Oxford ; it has 2 universities in it, and is inhabited only by Spa- niards. The houses are large, and built very strong ; the ground-floor is stone ; the walls of a prodigious thickness ; all above is wood, and so contrived, that every piece of timber has a connection with each other, all over the house : they are let into one another, and joined together, that the earthquakes, which are very terrible and frequent, may not throw them down. The convents are likewise very strong and handsome. The suburbs are very extensive, and well inhabited. In the year 1750 there was an earthquake here, which lasted 3 months, with almost continual tremblings, which at last broke out in an eruption, in a small island in the middle of a large lake, all round which the bottom is unfathomable. The third day after the commencing of the eruption, there arose 4 more small islands in the lake, all burning ; and about a mile distance from one there is a continual fire, which comes out of the water, where there is no ground, for upwards of 100 fathoms deep. This happened but 4 years ago. LXIF. An Essay on the fVaters of the Holy Well at Malvern, Worcestershire. By J. Wall, M. D. p. 459. [Reprinted in this Author's Medical Works, with some important additions relative to the chemical analysis of the Malvern-water, by his son Dr. Martin Wall, of Oxford.] LXV. On the Case of a Man who Died of the Effects of the Fire at Eddystone Lighthouse. By Mr. Edward Spry, Surgeon at Plymouth, p. 477- On the 4th of Dec. 1755, at 3 in the afternoon, Henry Hall, of East-stone- house, near Plymouth, aged g4 years, of a good constitution, and extremely active for one of that age, being one of the 3 unfortunate men, who suflered by the fire of the lighthouse at Eddystone, Q miles from Plymouth, having been greatly hurt by that accident, with much difficulty returned to his own house. Mr. S. being sent for found him in his bed, complaining of extreme pains all VOL. X. 4 R 674 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. over his body ; especially in his left side, below the short ribs, in the breast, mouth, and throat. He said likewise, as well as he could, with a hoarse voice, scarcely to be heard, that melted lead had run down his throat into his body. Having taken the proper care of his right leg, which was much bruised and cut on the tibia, Mr. S. examined his body, and found it all covered with livid spots and blisters; and the left side of the head and face, with the eye extremely burnt; which having washed with linen dipped in an emollient fomentation, and having applied things used in cases of burning, he then inspected his throat, the root of his tongue, and the parts contiguous, as the uvula, tonsils, &c. which were greatly scorched by the melted lead. He ordered him to drink frequently of water-gruel or some such draught ; and returning to his own house, sent him the oily mixture, of which he took often 2 or 3 spoonfuls. The next day he was much worse, all the symptoms of his case being height- ened, with a weak pulse ; and he could now scarcely swallow at all. The day fol lowing there was no change, except that, on account of his too great costive- ness, he took 6 drs. of manna dissolved in 1^ oz. of infusion of senna, which had no effect till the day following ; when just as a clyster was going to be ad- ministered, he had a very fetid discharge by stool. That day he was better till night, when he became very feverish. The next day, having slept well the pre- ceding night, and thrown up by coughing a little matter, he was much better. He began now to speak with less difficulty, and for 3 or 4 days to recover gra- dually ; but then suddenly got worse ; his pulse being very weak : his sides which grew worse daily from the first, now reddened a little and swelled; to which Mr. S. applied the gum-plaster. But all methods proved ineffectual, for the next day, being seized with cold sweats and spasms in the tendons, he soon expired. Examining the body, and making an incision through the left abdomen, Mr. S. found the diaphragmatic upper mouth of the stomach greatly inflamed and ulcerated, and the tunica in the lower part of the stomach burnt ; and from the gi-eat cavity of it he took out a large piece of lead of the weight of 7 oz. 3 drs. 18 grs. and of the shape of the bottom of the stomach. It will perhaps be thought difficult to explain the manner, by which the lead entered the stomach : but the account which the deceased gave, was, that as he was endeavouring to extinguish the flames, which were at a considerable height over his head, the lead of the lantern being melted dropped down, before he was aware of it, with great force into his mouth, then lifted up and open ; and that in such a quantity, as to cover not only his face, but all his clothes. ji Further Accoimt of the Preceding Case. By Mr. Spry. p. 480. Some persons having suspected the accuracy of Mr. S.'s statement in the pre- » TOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 675 ceding case, from imagining that the degree of heat in melted lead was too great to be borne in the stomach, without immediate death, or at least much more sudden than happened in this case; Mr. S. asserts the fact, not onlv by his own, and, if requisite, the oaths of others, but also by the following experi- ments, which from similarity of circumstances must not only render that pro- bable, but in the most convincing manner the absolute possibility of his as- sertion. He extracted in 3 pieces, from the stomach of a small dog, 6 drs. 1 scr. of lead, which he had poured down his throat the day before. The mucous lining of the cesophagus seemed very viscid, and the stomach much corrugated, though its internal coat was no-ways excoriated. The dog had nothing to eat or drink after; nor for 24 hours before the experiment, when, being very brisk, he killed him. He also took from the stomach of a large dog, in several pieces, 6 oz. 2 drs. of lead, 3 days after thrown in. The pharynx and cardia of the stomach were a little inflamed and excoriated ; but the cesophagus and stomach seemed in no manner affected. He gave this dog half a pint of milk just before he poured down the lead ; very soon after which also he eat of it freely, as if nothing ailed him ; which he daily continued to do, being very lively at the time he killed him. / From the crop of a full grown fowl, he in company with Dr. Huxham, f. k. s. extracted of lead one solid piece, weighing 2-^ oz. with Q other small portions, weighing 4^ oz. which lead was thrown down the fowl's throat 25 hours before. The fowl was kept without meat for 24 hours, before and after the experiment, eating (being very lively just before they killed him) dry barley, as fast, and with the same ease as before. The mucus on the larynx and oesophagus was somewhat hardened. The external coat of the crop appeared in a very small degree livid ; and the internal somewhat corrugated. The barley was partly in the oesophagus, though mostly in the craw, which was almost full with the lead. He took 2 oz. 1 scr. from the crop of another fowl, 3 days after the experi- ment, which fowl was very brisk to the last. Allowing, for a further satisfaction, that the experiment be tried, it is re- quisite in making it, that the melted lead be poured into a funnel, whose spout being as large as the throat of the animal (whose neck must be kept firmly erect) will conveniently admit of, must be forced down the oesophagus, some- what below the larynx, lest any of the lead might fall in it; and according to the quantity, either by totally, or partly obstructing the aspera arteria, cause imme- diate, or a lingering death ; which accidents happening in his first experiments on 2 dogs, directed him to proceed in the above manner. 4li2 676 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. He had a dog with lead in his stomach, which he intended to keep, to prove how long he could live. On the same Case of the Man, who Swalloiued Melted Lead. By John Hux- havi, M. D., F. R. S. p. 483. Our worthy commissioner, Fred. Rogers, Esq. sent the lead here mentioned, to Dr. H. 3 days after it was said to be taken out of the man (Hall) who was said to have swallowed it. He immediately sent for Mr. Edward Spry, an in genious young surgeon, of Plymouth, who attended this Hall during his illness, and extracted the lead from his stomach (as was reported) when dead. Mr. Spry solemnly assured Dr. H. that he did actually take the lead, that was sent him, out of the man's stomach, and offered to make oath of it. This Hall lived 12 days after the accident happened, and swallowed several things, solid and li- quid during that time ; and he spoke tolerably plain, though his voice was very hoarse. And he constantly affirmed, that he had swallowed melted lead. However, as the story seemed very extraordinary, and not a little improbable, Dr. H. did not chuse to transmit any account of it to the r. s. as he could have wished for more unexceptionable evidence ; for Mr. Spry had no one with him, when he extracted the lead, but one woman, Philips, the daughter of Hall, and another woman, who were also in the house, not being able, as said, to see the operation, but immediately called in after it, and Mr. Spry showed them the lead. He sent a very sensible gentleman to inquire into this affair, and he had this account for them. Mr. Spry was, to the best of his knowledge, a person of veracity, and he thought would not utter an untruth. But, what was more, on Wednesday he brought him a live young cock, into the crop or craw of which, he had the day before poured somewhat more than 3 oz. of melted lead. The cock indeed seemed dull, but very readily pecked and swallowed several barley-corns, that were thrown to him. He had the cock killed and opened in his view, and in the crop they found a lump of lead weighing 3 oz. and some other little bits of lead. He made no doubt the cock would have lived several days longer, if it had not been then killed. There seemed a slight eschar in the cock's mouth, occa- sioned by the melted lead, and the crop seemed as if parboiled. This experiment is very easily made, and seems to confirm the probability of Mr. Spry's account. LXFI. A Further Account of the Success of some Experiments of Injecting , Claret, &c. into the Abdomen, after Tapping. By Mr Christopher War- rich, p. 485. The first case in which this experiment was tried, was that of the poor wo- man at Cubartj mentioned in the Transactions, N° 473, who was injected with VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 677 claret and Bristol water, and about a week after the operation died suddenly.' She was upwards of 30 years of age. > Tlie '2d instance was that of a young woman of St. Kivern, who was about 25,' and had been 3 times tapped in the common way. Here they made use of 2 punctures, according to Dr. Hales's method, as recommended in the Transac- tions, N° 478, and claret and tar-water for the injection ; which was conveyed into the abdomen through one canula, while the dropsical lymph passed off through the other. A few hours after she complained of much pain in her bowels, and on drawing off* the whole contents at once, she fell into a syncope, in which she remained till about 12 o'clock, the next day, when she died. It may not be amiss to mention, that her breath was immediately affected by the tar-water, and the smell of it continued to her death. The 3d instance being somewhat singular, Mr. W. thought proper to relate it in all its particulars. March, 1752, he was called to Flushing, a small town opposite Falmouth, to attend the tapping of a poor woman, who was about 40 years of age, and laboured, as was imagined, under an ascitical dropsy, occa- sioned by 3 suppression of her menses, that happened about a year before. She had been told of his successes with Jane Roman, and desired his assistance, together with Mr. Rice, Mr. Cudlip, and Mr. Lillicrap, of the same profes- sion. She was a married woman, of a chearful temper, had never had a child, and to all appearance was a proper subject for the operation, she being never thirsty, and her extreme parts being of the natural size : the abdomen was like- wise evenly and equally distended, and of a great magnitude ; but the fluctua- tion was not altogether so manifest as might have been expected. From these circumstances they made no difficulty to resolve on the operation, and determined to try, at the same time, the efficacy of a subastringent injection. A sufficient quantity therefore of claret and Bristol water being got ready, Mr. Rice made the puncture ; but on withdrawing the perforator, instead of lymph, nothing but a thick, ropy, gelatinous fluid came through the canula, in colour resemb- ling red port wine, or rather grumous blood. The singularity of this did not however alter their measures. Two gallons of it were immediately drawn ofl^, and half that quantity of claret and Bristol water injected in its stead. This they proposed to have repeated the next day, and as the circumstances of the patient would admit ; and to continue daily, till the whole contents should be gradually discharged ; fearing that a total discharge in the ordinary way would have brought on a syncope. But when they attended her again on the day following, not one drop of any fluid came through the canula ; and a 2d and a 3d puncture was attended with no better success. Soon after this, the whole abdomen became painful and distended, frequent rigors came on, and a delirium, in about 12 hours, carried her off. On opening the body the day following, not 678 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. one drop of any fluid was found in the cavity of the abdomen ; an enormous cystis, which might have contained, when full, about 6 gallons, having com- pletely filled the whole extent of it. There were likewise attached to the coats of it 5 large bodies of fungus flesh, the least of them larger than a man's fist. Each of these, when cut open, appeared to be divided into cells, full of white glutinous pus. This extraordinary mass adhered only to the fund of the uterus, and together with it, the fungus substances, and vagina, when taken out, en- tirely covered a middle sized pillar and claw tea-table. They now found, that in the night the canula had accidentally slipped out of the cystis ; and that the operator, in making the 2d or 3d puncture, had fallen upon one of these fungous bodies, which gave occasion to the above-mentioned disappointment. On pro- ceeding to a further examination of the abdomen and thorax, they found every thing sound, and in its proper state, excepting the posterior part of the right lobe of the lungs, which was full of purulent matter, and adhered to the pleura. Mr. W. adds, that the ovaria did not distinctly show themselves, so as to satisfy any inquiry about them ; but this perhaps might be owing to the hurry or in- accuracy of the dissector. Whether these miscarriages are sufficient to discredit a method of practice, which has the appearance of being the most rational one yet found out for managing a dropsy, Mr. W. leaves to the determination of better judges. The frequent miscarriages that happen in the ordinary way, seem suflScient to justify every attempt to render the success of it less precarious. If any further trials of it be made, he would beg leave to recommend its being done before the viscera are too much injured by the dropsical lymph; and if the evacuation be made at different times, with a view of preventing a syncope, that brandy, or some such liquor, properly diluted, be made use of instead of claret, which, as he -apprehends by the heat of the body, may be apt to turn sour. It may be likewise proper that the head of the patient, during the evacuation, lies lower than any other part of the body. As in the 2d instance above-mentioned, tar-water had been recommended by some gentlemen of the profession, then preseot, instead of Bristol-water, Mr. W. some time after the death of his patient, injected a pint of it warm into the belly of a small cur, to see how far the effect of it differed from that of claret and Bristol-water. The dog immediately fell into great agonies, and in about 2 hours died. The abdomen being opened, all the intestines were found greatly inflamed. He then tried claret and Bristol-water, also port wine and fountain water, on other dogs, after the same manner. Each of these injections was re- tained with little or no inconvenience, except intoxications : and in 48 hours the dogs became well again, the injection being entirely absorbed. . It occurred to him in making these experiments, when the power of absorption seemed very TOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 679 considerable, how far it might answer in preventing a syncope, or for other pur- poses, that a fit quantity of a properly adapted injection be left undischarged, after tapping, which might be either absorbed or drawn off at proper intervals, as the strength of the patient might admit. LXVII. On the late Discoveries of Antiquities at Herculaneum, ^c. in Two Letters from Camillo Paderni, Keeper of the Museum Herculanei. Trans- lated from the Italian by Robert fVatson, M. D.^ F, R. S- Letter Isl, Dated at Naples, Ju7ie 28, 1755. p. 49O. In April last, a little beyond La Torre della Nunziata, where stood the an- cient Pompeii, in digging near the amphitheatre, there was discovered a marble capital of the Corinthian order. On making further trials, there were found 2 pilasters of white marble, about ]0 feet high, fluted on every side, with capitals and bases of the Corinthian order. On one side of these pilasters have been found a series of 9 other pilasters, about 7 feet high, equally wrought Nyith the larger : there were likewise 5 other pilasters on the side of the other great one, making in all 16; which are all of one piece, exclusive of the capital and the base, except one, which is composed of 1 pieces. They were all excellently preserved, and were standing ; forming a portico before a building. All the buildings, which are in Pompeii, are of the same constitution with those of Herculaneum and Stabiae ; that is, of one story. The portico is continued on the sides, but the pilasters are not of marble, but of brick covered with stucco, and coloured with green, and are not fluted like those of marble. One only of the sides is yet undiscovered, and we must wait to see the side opposite to the front, and the rooms within, to be able to speak decisively. The front was all painted in the grotesque manner ; but little, and that ill preserved, remains. There were no ornaments of stucco, or marble ; the walls indeed were coloured, and there were some small* niches formed in the walls, each of which corresponded to one of the pilasters, and consequently there were 18 in number. In several of them were found certain figures, some of earth, others of marble, in this order ; first was placed one of marble, then one of earth : those of marble were 9 small Hermae, among which there is a Hercules crowned with oak, some satyrs, fawns and Bacchantes. Two of them are of the old red, and the other of the old yellow marble, and are of an indifferent style. Those of the baked earth consist of 4 figures. The first is a Barbarian king, who stands erect with his right hand under his chin in a pensive manner, and wears his chlamys clasped with a fibula on his right shoulder. But what makes this figure the more curious is, that the whole body forms a vase, on the back of which there is a handle to hold it by. Behind the head there is a little tube, through which water or some other liquor was poured in, and the mouth 68b PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. of the figure is open, through which the hquor was poured out. The height of it is ahout 10 inches, and the style rather low. The 2d figure is of the same height and character, as to the workmanship ; but what it represents, renders it singular. This, figure seems sitting, with its legs stretched out, which are distorted like those of some dwarfs. It has a great head ; the mouth, eyes, and nose, of which are extremely overcharged. It is dressed in the praetexta. On the breast is the bulla aurea, the string of which surrounds its neck, and is held with the right hand ; with the left it holds the tablettes called pugillares, on which the ancients placed wax, and wrote on it with a style. These pugillares are exactly like those dug up at Herculaneum, and which are preserved in that museum. Besides, it bears a great priapus, and be- hind is seen the breech. This was made for a vessel, such as that described above, except that besides that the mouth of this figure is pierced, the liquor can also be poured from the priapus. The third figiu'e is entirely like the preceding, except in its dress, which is rustic, and bound round the waist with a cord, to which is fastened somewhat that cannot be made out, but which appears to be a little case to hold some- thing : the rest is not overcharged, but is rustic. It holds in its right hand a loaf, and its left hand is covered with its dress, and, like the other, it shows its breech and priapus. Probably such vessels were used for drinking the liquor coming out of the priapus, this being not unusual with the ancients, as Ju- venal in his second satire, gives us to understand ; Vetreo bibit ille priapo. The last figure represents the Roman Charity. She is sitting, and with her left hand embraces her father, and with her right presses the breast which her father sucks ; who is expressed in this figure totally emaciated. This does not, like the others, form a vessel, but simply exhibits the story. The style is mo- derate, its height near the same as that of the others. This last groupe is co- vered with a varnish of glazing, like that which covers earthen plates and things of that kind. There were found, in the before-mentioned niches, 2 little busts of baked earth, of the same height ; one wants the head. This is all that is found in that part of the building, which is supposed to be the front. to In a little closet, the dimensions of which are about 6 feet in length, and 4 in breadth, discovered the 13th of last month, was found a very fine tripod, about 3 feet high, extremely well preserved. In short, it is one of the most beautiful pieces of antiquity in the whole world. It is formed of 3 satyrs, young, and all exactly alike. Their heads are most beautiful, with a cheerful countenance, and the hair well disposed with a ribband, that surrounds the head. On the forehead stand 2 small horns, which are united. The right hand rests on the side of the body, and the left is open, with the arm somewhat extended. They have a great VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 681 satyresque priapus. The legs are united, and they place their feet on round bases, which have been turned in a lathe, and then covered with leaf silver. Their tails are twisted round a ring, by which they are suspended. The 3 satyrs support with their heads the hearth of the tripod, which is of excellent work- manship, and has 3 moveable rings, which serve to remove the tripod from one place to another. One of these rings is wanting, and could not possibly be found. Whence we may suppose, that originally it was likewise wanting. On the hearth is another ornament united to its circumference, and forming a kind of radiated crown, which crown has also 2 handles, but not moveable. These serve to place the crown on the hearth. The bottom of the hearth is not of brass, like the rest of the tripod, but of baked earth. The above-mentioned closet, where this tripod was found, is all painted, and entire, with the ceiling unhurt. In the walls of it was a table of white marble, fastened in the wall itself, which might be called a side-board, and which was extended along the sweep of the room. On this table was found a crescent of silver, about 5 inches in diameter, and on the edge of its middle are 2 small holes to receive a string to support it. Perhaps this was an amulet, for we have another of the same metal, but smaller, with its supporter of silver, which has been long found. On the same table was another amulet of silver, about an inch in height, which represents Harpocrates. This figure has its finger near its mouth, the lotus on its head, and wings on its shoulders. On the right shoulder hangs a quiver, and its left arm holds a horn of plenty, and leans on the trunk of a tree, round which is a serpent, and at the foot of the trunk stands an owl. There was found a kind of fibula, which is of gold, and is extremely well preserved. Its form is round, and made like a large button. On the back there is a gold wire fastened to one side ; the other end of which is fastened in a small piece of gold, soldered into the fibula. The whole is little more than an inch in diameter. There were found also 2 other figures ; one is of marble, about a foot high, representing a woman ; it is of no great value ; the other is of ivory, but there remains nothing but the name, and a part of the face, by which may be perceived, that it is the work of an excellent Greek hand. All the rest consists as it were of minute leaves, which are so brittle that they cannot be united. Its height is about a foot. There was also found in the same closet, on the same marble table, one of the most beautiful statues ever seen, and so admirable, that I know not how to begin to describe it. Its height is little more than 3 inches, by which you may conceive what pains have been taken with it. It stands on its feet, and is quite naked, and presents a priapus, which is not satyresque, with a most jx^rfect con- trast of attitude. One observes through the whole figure a most perfect skill in anatomy, where the smallest muscle is not lost, aiul at the same time it seems VOL. X. 4 S 662 PHILOSOPHICAL TRANSACTIONS. ["aNNO 1755, not dry or hard, but palpable flesh. It is of a noble and excellent stile. Its head is somewhat rustic, with a goat's beard and ears. It has a laughing coun- tenance, turning its head with much grace, and brings its first finger of the left hand to its face. It extends and raises its right arm, which terminates in a manus impudica. Our Neapolitans, and I have seen the same in our peasants about Rome, frequently wear in their hair a pin, the head of which consists of such a hand; and they say, that they wear this against an evil eye; and in Naples some of these pins are worn by children. "We have found several of these small hands at Herculaneum. It is observable, that these Priapi frequently had this hand; for among the many which remain under my care, there is one with human ears, and with this hand, which together with the whole arm forms a priapus. The head of the figure is covered with a cap, which is folded down behind; and its base is low and round, and well fitted. In fine this may be called one of the most excellent curiosities. In one of the other rooms there was a fine pair of scales, in which there are some remains of the strings made of a kind of fine coral, and the strings remain in some of the rings. There were found also many vessels of earth and fragments of metal. In the ancient Stabiae they go on digging; but it is long since any thing of value has been found there, except that in the beginning of this month 2 small statues of brass were discovered. One represents a Venus, but of no value. The other a Panthea with a rudder, horn of plenty, lotus, modius, and sickle. It is but of ordinary workmanship. Many vases of earth, some of glass, have been found. A great vessel of copper with a handle, a singular funnel, a beautifiil little vase of rock crystal with its cover, andasimpulum or ewer; divers medals as well silver as copper, well preserved, but common, and various pieces of leaden pipes, have also been fonnd there. The same may be said of Herculaneum ; for since the month of March, after the colossal bust of brass was found, they have discovered nothing of value, ex- cept one thing, which ought to make much noise among the learned, and which I believe to be the only one of its kind in the world. This is a little leg and thigh of metal covered with silver, and which is 5 inches long. On the external part of it is described a sun-dial formed on a quadrant, and as the thigh forms a quarter of a circle, the workman has taken the centre of this quadrant from the extremity or leg of the ham or gammon, and hence has drawn hour lines, which, with the lines that mark the months, form the usual compartments, some larger and others smaller, which are divided 6 by 6, as well in height as length. Below the inferior compartments, which are the less, are read the names of the months placed in 2 lines in a retrograde order, so that the month of January is the last in the first line, which bears the other 5 following months. In the 2d line are described the 6 other months in their natural order; so that the month of De- VOL. XLIX.] PHILOSOPHICAL TKANSACTIONS. 683 cember is under January, and so the months shorter and longer, 2 and 2, liave one common compartment for each couple. Almost on the edge of the right side, there is the tail of the animal somewhat bent, and this performs the office of the gnomon. On the extremity of the bone, that is, of the leg, or centre of the quadrant, there is a ring to hold the dial in an equipoise; and it is sup- posed that in that place was fastened its plummet, such as in the like dials is to fall on the present month, to determine the shadow of the gnomon on the horary lines. It is observable also, that as these dials were described on a plain surface, according to a fixed rule, the surface of this metal ham being in one plane con- cave, in another convex, one cannot easily guess what rule the woikman used to describe a dial of so difficult a kind, on a surface so irregular. I must not neglect to acquaint you with what has been found in a trial made at Cuma, where were situated some sepulchres, which afforded many curious things. In May last, our miners opened a tomb of the family Pavilia, which formed a small chamber. On the floor were 3 corses, or rather their bones, which were included in 4 pieces of the piperine stone. These 4 stones formed fbr each corse an oblong case. The engineer, who was present at the discovery* told me, that one of these bodies was all covered by a substance unknown to him ; but from his account I comprehended what it was. The corse was covered with a cloth of amianthus, which, as it was large, remained in this situation all on a heap, but calcined by the salts of the earth, for which reason it was neces- sarj' to take it up in pieces, it being become extremely brittle. However, to be more sure of my opinion, I had a mind to try it in the fire, where it remained unchanged; whence there is no doubt but that it is amianthus. There were found a great many little pieces of paste as large as beans, which were taken by the miners for comfits but are the confection, which used to be put on dead bodies. They are composed of myrrh and other spices, and even now retain a verj' strong smell. There was found some cloth reduced almost to nothing, which had some ornament of gold embroidered on it, or rather wove into it, as is more probable from the gold thread. On the above-mentioned body were found some pieces of paper, for I have great reason to think it such from the trials, which I have made on the old papyrus, of which we have about 800 vo- lumes. This paper on one side is coloured with red minium, on the other it is black. Besides this paper, there were found a mirror of metal, and 3 tesserae, or dice. Under the corse, or bones, was found a padlock, through which were passed 3 iron strigils, and another that w^as broken. It is remarkable, that in all the other sepulchres, that were opened at Cuma in the month of May, there were found a mirror, 3 tesserae, strigils, and some very small fibulae of bone. In the above-mentioned sepulchre was found a small lectisternium, or rather pulvinar 4 s 2 081 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. deoriim, which was very much decayed. It is mounted in iron. The ornaments which compose it being of ivory, the rust of the iron has as it were destroyed the whole. So that there were collected but a few remains of the 4 pillars, some pieces of the bands, which went round the frame, 8 pieces of ivory, of an oblong form, in each of which was engraved a figure of some unknown deity, all of the same design, but in a bad style; and two heads of a horse, which are fellows, and belong to the lectisternium, not unlike that great one of brass, which is now in the Royal Museum. There were found also several little vases of earthen ware, whose forni is this : they have a long neck, with a mouth propor- tionably straight; the body is oval, which towards the bottom is so small, that they cannot stand upright. The misfortune is, that 1 of these vases, which are of oriental alabaster, and of the most excellent workmanship, are both broken in the middle. Near this sepulchre there was opened another, belonging to the freed men of the Pavillia family. There we found many glasses and pieces of earthen ware, and two most beautiful earthen lamps. On one of them is a Hercules going to slay a serpent with his club, which he holds in his left hand. On the other is a priestess of Bacchus, which in one hand holds the sacrifical knife, and in the other the half of a victim. There are also 2 very small wine-glasses, which contain, the one a liquor of the colour of red wine, the other a liquor more limpid than white wine, but without any smell. In this tomb were found also the usual dice, strigils, mirrors, and fibulae. The bones and ashes were in urns made of earth. Four other sepulchres also have been opened, in all of which were found the usual strigils, mirrors, tesserae and fibulae. In one of them was found a little earthen urn with its cover. Within the same tomb was a small urn of glass elegantly made, containing the ashes of a child. Near the said urn were found several httle things, which probably were the playthings of the child; these were two very small goblets of baked earth glazed, with a handle to each ; two small water ewers, of the same materials, with ornaments; these also are extremely small; another vase of common earth, which forms a recumbent ox, on the back of which is a hole to receive the water, which was poured out through the mouth; and there is a handle on one side of the body. In this same sepulchre was found a monstrous priapus of red earth. This figure has wings, and is much overcharged. All these things, which I have described, are preserved by me in the Royal Museum, in a separate apartment from that in which is preserved what has been found at Herculaneum, Pompeii, and Stabiae. I have already filled 8 chambers with antiquities ; and because those are not sufficient, I shall begin to place many other things, which hitherto I have been forced to keep in confusion in other chambers, which are on the same floor. A single volume of the Papyrus rOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 685 is unfolded, being that which treats of music. At length the name of the au- thor, who was called Philodemus, is found written twice, at the end of the piece. The name is written once in a small, and a second time in a large hand, and in a good Greek character. They are now beginning to open, or rather to unroll another manuscript; but hitherto without much success; from some frag- ments we may collect that it treats of rhetoric. Dr. fVatson makes the following Observations on the preceding. I think it probable, that Philodemus, the author of this treatise on music, was the Epicurean philosopher of that name, who was, as Strabo informs us, a native of Gadara in Syria. He wrote many pieces in prose and verse, and his ]Oth book, TTfpi ruv (f)iXo(ro(puv trmrx^iu;, is quoted by Diogenes Laertius. Indeed his sect, time, and abode, will allow of the supposition of his writings on music being at Herculaneum at the time of its destruction. He resided at Rome, and was the acquaintance of Tully, and the preceptor of Lucius Piso the consul. We learn from Asconius Pediaims, that it is Philodemus the Epicurean, of whom Cicero speaks with that admirable mixture of praise, and invective, and excuse, in his oration against Piso; where he says, that he knew him to be a man of elegance and polite literature; tliat it was from him that Piso learned his philo- sophy; which was, that pleasure ought to be the end of all our pursuits; that indeed the philosopher did at first divide, and distinguish the sense in which that maxim was to be understood; but the young Roman perverted every thing to make it favour his inclinations and pleasures; and the Greek was too polite and well-bred to resist too obstinately a senator of Rome. He then tells us that Philodemus was highly accomplished in philosophy, as well as polite literature, which other Epicureans were apt to neglect; that he wrote verses, which were so sweet, so elegant, and so charming, that nothing could exceed them; that he was betrayed into a too hasty friendship with Piso, from which he could not dis- engage himself without the imputation of inconstancy, and that, rogatus, invi- tatus, coactus, ita multa ad istum de isto scripsit, ut omnes libidines, omnia stupra, omnia caenarum conviviorumque genera, adulteria denique ejus, delica- tissimis versibus expressit. I have met with some epigrams of Philodemus yet extant, some of which are, in my opinion, most facetious, and elegant. We might have had many more, had not Planudes, as the scholia inform us, rejected such out of his collection, as he thought too loose and voluptuous. Horace seems to have had some of these epigrams in his eye more than once, when he wrote his 2d satire of the first book; particularly where he says, banc Philodemus ait; sibi, quae neque magno Stet pretio, neque cunctetur, cum est jussa venire. Is not this almost a translation of the 686" rniLosoPHicAL transactions. [anno 1755. TlavTx, xai airna'ai TroXXaiti ipsiJ'oju.Ei'ri. I will give the whole epigram, as a specimen of the style and manner of Phi- lodemus ; but must beg, that in reading the third verse you would recollect what Homer says of the girdle or cestus of Venus, that it contained all kind of de- lights and blandishments, love, persuasion, and desire. 4>i>.oJ'nft!s nrtyfo.jJ.jj.K. MiXiC)) x«> litXavHd-a ^iXxiviov, aWa, (riXmuv OuX0T£f», K ajMm p^pura TjaiiKOTipTi, Kai xto-Tu ^uvtvfo. jotaywrtpa, xai TrajEj^aira; Ylomra, xai aiTno-ai iroAAaxi tpuSofAfvr,. ToiauTWk (rTipyoi|M.i 4>iAaii'io)', *X.P'^ "" '''P''' AXXtii', ft) xfuirtn Kuirpi, riXttoriftw.* Extract of the second Letter from Camillo Paderni, dated at Naples, July 1Q, 1755. p. 307. A cameo of great excellence was found the 9th of this month. This cameo is in alto relievo. It is about an inch and a half long, and almost as much in breadth. It represents a half length of Ceres. The head is in profile, and has a noble and beautiful air. It is turned, together with the body, a little to the left. The left arm is a little raised, and holds in the hand some ears of com. The right arm is lower, and close to the body. The right hand takes hold of part of a fine garment, or shift, with which the figure is in part covered. The head is adorned with a diadem; and the hair, which is of excellent workmanship, flows on her shoulders, tied with a single ribband, which rests on her neck. The stone, of which the head is composed, is pellucid, and the rest of the figure is cut out of a chalcedony by a Greek master; it was found at Stabiae, where they continue to dig. In the same place were found also buried several vases of metal and glass very well preserved. At Pompeii within these few days was found a most beautiful wine-strainer, small, but finely pierced, in a better taste than those already found, which are of brass. In this same place was dug up an ink-standish, with some of the ink, which I likewise preserved. There has been met with also an iron ax. There have been found, and they go on daily to find, many pictures. If the ancients had not dug in this place, we should have discovered many more things; for we find that they have taken away even some of the pictures. * Since the death of the learned Dr. Watson, which happened March 2, 1756, soon after his translation of these two letters of Camillo Paderni, and his observations on the former, were read at the Royal Society, another epigram of Philodemns has been taken notice of, published at Leipsic in 1754, by the celebrated Mr. Reiske, which ajjpears likewise to have been alluded to by Horace in the passage in part cited above from his second satire of the first book, ver. 120.— Orig. • ' VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 687 JjXFII. Of the Earthquake felt at Glasgow and Dumbarton; also of a Shower of Dust Jailing on a Ship bettveen Shetland and Iceland; in a Letter from Dr. Robert ^Fhytt, Prof, of Medicine in the Univ. of Edinburgh, p. 509. The earthquake at Glasgow and Greenock happened in the night between the 30th and 31st of December, nearly at the same time. It was felt at Glasgow by almost every person that was awake, and out of bed, and also by some in bed, and who were not fast asleep. There were 3 successive shocks, or risings as it were of the earth. It was felt not only at Glasgow and Greenock, but also at many other places in the neighbouring country ; particularly at Dumbarton. By letters from a passenger on board a ship bound from Leith for Charles- town in South Carolina, it appears that on the night of the 23d or 24th of Oc- tober last, when the weather was quite calm, a shower of dust fell on the decks, tops and sails of the ship, so that next morning they were covered thick with it. The ship at this time was between Shetland and Iceland, about 25 leagues distant from the former, and which was the nearest land. This shower was probably owing to the great eruption, which happened at mount Hecla in Iceland, in October. LXVIII. Extract of a Letter from Mans. Bonnet, F. R. S. Dated at Geneva, Jan. 30, 1756, concerning the Earthquake on the \Ath of November, 1755, in Fialais in Swisserland. Translated from the French, p. 511. Valais is thought to have been more shaken by the earthquake than our city and its neighbourhood. The earthquake felt here, happened Nov. 14, at 3 in the afternoon. It proceeded from the north, and lasted a minute. The earth opened on the mountain ; and the opening was large enough to thrust one's hand in, and no bottom can be found. In another part of the mountain the earthquake opened a spring sufficient to turn 2 mills. The earth has been opened in another place. The opening is round, and no bottom can be discovered. The eartVi continues to shake almost every day, but these shocks are much gentler than the first. LXIX. Extract of a Letter from Mons. Allemand, F. R. S. Translated from the French. Dated Leyden, Jan. 27 , 1756. p. 512. On the night between the 26th and 27th of the last month, December 1755, between 1 1 and 12 o'clock at night, there was a considerable earthquake on the frontiers of this country. It was felt at Liege, Maestricht, Nimeguen, Arnheim, and Breda. There were 3 different shocks, the last of which happened at about 4 in the morning, but without any noise or accident. I have been informed by letters from Swisserland, that several shocks were felt there, and that the salt- 688 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. springs of Bevieux have been rendered more salt. At Amersfort, in the province of Utrecht, on the 1 5th of this month, was felt a shock of an earthquake, which occasioned great consternation, but no damage. LXX. Of some Fungitce and other Curious Coralloid Fossil Bodies. By Thomas Pennant,* Esq. p. 513. Fig. 1, pi. l6, was found in the lime-stone quarries in Coalbrooke-dale, Shropshire, the greatest magazine of coralloid fossils that I am acquainted with. The length of this elegant body is equal to that drawn, and its greatest diame- ter, which is near the top, is about an inch and a half. It is exactly of the form of a pear, with a small portion of stalk remaining ; and its whole surface is • Thomas Pennant, Esq. was bora in Flintshire in the year 1726. His father was a gentleman of good family and independent fortune. Mr. Pennant has himself given us the chief particulars of his life in a small work which he plea- santly chose to write in the character of his own shade : it is entitled " The Literary Life of the late Thomas Pennant, Esq." In this publication he informs us that his zeal in the pursuit of Natural History was first excited by a present of Willughby's Ornithology, which was made to him by a re- lation, when he was about 12 years of age. In 1754 he was elected a Fellow of the Antiquarian Society, and in 1767 a f.r.s.; having distinguished himself by his ingenious and useful work the British Zoology, and other scientific publications. The British Zoology was at first undertaken for the benefit of a Welsh school, but the splendid nature of the work in its folio form seems to have operated to its disadvantage as an affair of profit, and it was never continued on a similar scale, but was republished in 4to, in which state it is too well known and esteemed to require particular de- scription. In 1757 Mr. Pennant was, at the instance of Linnaeus himself, made a member of the Royal Academy of Sciences at Upsal, and he continued to correspond with Linnaeus till the age and infirmities of that illustrious naturalist obliged him to desist. In 1765 Mr. Pennant travelled into France, where he passed some time with the celebrated Count de BufFon. He went into Switzerland, where he commenced an acquaintance with Haller, and at Zurich with the Gesners, one of whom was the descendant of the famous Conrad Gesner. He then visited Holland, and at the Hague found the celebrated Dr. Pallas, with whom he ever after maintained a constant correspondence on subjects of natural history. In the midst of these his reigning pursuits he never neglected the com- pany of convivial friends, or shunned the society of the gay world. Mr. Pennant lived some years after the publication of his Literary Life, during which time he still pursued, with as much assiduity as his increasing infirmities would permit, his usual course of study, and died at his seat at Downing in Flintshire in the year 1798. It remains to add, that Mr. Pennant's person was elegaut, his manners in the highest degree polished, and what is of infinitely more importance, tliat his character was equally estimable. The publications of Mr. Pennant are numerous, and are remarkable for variety of information, which is generally detailed in a very entertaining manner. His tours in Scotland, Wales, &c. are held in great esteem. His Indian Zoology contains descriptions, accompanied by plates, of a {ey/ of the rarer Indian animals, but was never continued to any farther extent. His " Outlines of the Globe," a vast work, has as yet been only published in part : of this the " Arctic Zoology" can hardly be too much commended : the parts relative to India, New-Holland, and some other regions have also appeared ; and it is greatly to be wished that the whole of a work so much abounding in general as well as zoological and geographical information should at length be presented to the public. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 689 covered with small shallow polygonal cells, the stalk excepted, which is perfectly smooth. Fig. 2 is a small fungites from the same place, of the same size with the figure ; the top is convex, and thick set with minute circular cavities ; the stalk tends to a conoid form, and is coarsely striated lengthways. Fig. 3 has a very deep cup-like cavity in it, the bottom of which is very finely radiated ; the remaining part covered with small tubera, not unlike those that sometimes are seen in the insides of flints and pebbles. Externally it is irregu- larly cellular, but the stalk is striated. Fig. 4 is a very singular body, and the most remarkably shaped fungites I evar saw, being exactly oval on one side, and flat on the other, without the least appear- ance of stalk. The oval or lower part is reticulated with polygonal cells, like fig. 1. The flat or upper part is striated semicircularly, the striae passing from one side to the other, and then reverting. Fig. 5 he received out of Italy, under the name of lapis subluteus Veronensis stellis majoribus. The surface is finely marked with star-like cells, which are elegantly striated from their centre ; and their edges rise a little prominent. The lower part of this stone is of a conoid shape, and irregularly indented with coarse circular rugae. Fig. 6 was found at Coalbrooke-dale ; is of a white colour, and very smooth both on the sides and top, without any appearance of striae : but what renders this very singular, is the remarkable thinness, its greatest diameter not exceed- ing the 8th of an inch. Fig. 7 was found at the top of one of the highest mountains in this county, near Caer-gwrle, in a reddish loamy soil, with various other diluvian remains. It is of a conoid shape, but considerably incurvated ; the sides are striated lengthways, and likewise circularly, but the circular striae are much less frequent than the others. At the thicker end there appears to have been a deep cup-like cavity, the greatest part of which had by some accident been destroyed, but what remains is radiated with thin and very prominent ridges placed at equal distances from each other. On one side is a small flat fungites. Fig. 8 is a fungites from Coalbrooke-dale, seemingly formed of 3 or 4 smaller, inserted one into the other. It has the same cavity on the top as the former, with a minute striated concha anomia in it. Fig. Q. This fungites is almost straight ; has a small cup-like striated cavity on the upper end ; is encompassed with prominent ridges on the sides ; and is striated lengthways. Fig. 10. This species came from Piedmont, and differs fi-om all the rest. It may be called an echinated fungites, having 6 orders of sharp-pointed studs running lengthways from top to bottom, and between each order appear some very minute longitudi- nal striae. The upper part, instead of a cavity, is composed of several thin la- VOL. X. 4 T figO PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. TTiellae rising above the sides. Fig. 1 1 is a Coalbrooke-dale production, and is a cluster of fungitae, though only 2 appear in the figure. This varies from some of the foregoing in the shape of its head, in the middle of which is a shallow circular cavity, its sides rising a little prominent, and the striae, which commence the inside, pass over the ridge, and are continued to the edges. Fig. 12 is from the same place. The cup-like cavity in this is pretty deep, and radiated with deep strigse : and the sides are marked with very distinct ridges running length- ways, though sometimes interrupted by circular furrows. LXXl. An Account of Inoculation, by Sir Hans Sloane, Bart, given to Mr. Ranhy to be published. Anno 1736. p. 31 6. Sir H. S. had heard by several reports from China and Guinea, but especially from Turkey, of the inoculation of the small-pox ; and took an opportunity, when Dr. Wm. Sherrard was English consul at Smyrna, to desire the favour of him to inform him of the truth and success of it. In answer to which he told him, that the consul from Venice residing there, a physician. Dr. Pylarini, had taken particular notice of that practice, and had promised to satisfy him about it ; which he did by a letter, which was printed in the Phil. Trans, in 17^6, and he believed at Venice. This notice lay dormant till Mr. Wortely Montague, (then ambassador from England at the Porte) and the Lady Mary had inoculated their son at Constanti- nople, and wrote about this practice, and the advantages of it, to the court and their acquaintance here, and afterwards brought into England their inoculated son, in perfect health. The princess Anne, then princess royal of Orange, falling ill of the small-pox in such a dangerous way that her life was doubtful, the late Queen Caroline, when princess of Wales, begged the lives of (3 condemned criminals, who had not had the small-pox, in order to try the experiment of inoculation upon them. But Mr. Maitland, who had inoculated at Constantinople, declining for some reasons to perform the operation, lest it should be lost. Sir H. wrote to Dr. Terry at Enfield, who had practised physic in Turkey, to know his opinion and observa- tions about it ; who returned him this answer, that he had seen the practice there by the Greeks encouraged by their patriarchs ; and th^t not 1 in 800 had died of the operation. On his speaking to Mr. Maitland, he undertook the operation, which succeeded in all but one, who had the matter of the small-pox put up her nose, which produced no distemper, but gave great uneasiness to the poor woman. After their recovery, in order to obviate the objection made by the enemies of this practice, that the distemper produced by it was only the chicken-pox, swine-pox, or petite verole volagere, which did not secure persons against having the true small-pox, Dr. Steagertahl, phvsician to the late king, VOL. XLIX.J PHILOSOPHICAL TRANSACTIONS. 6qI and Sir H. joined their purses to pay one of those who had it by inoculation in Newgate, who was sent to Hertford, where the disease in the natural way was epidemical and very mortal, and where this person nursed and lay in bed with one, who had it, without receiving any new infection. To make a further trial, the late queen Caroline procured half a dozen of the charity children belonging to St. James's parish, who were inoculated, and all of them, except one (who had had the small-pox before, though she pretended not, for the sake of the reward) went through it with the symptoms of a favourable kind of that distemper. On these trials, and several others in private families, the late queen, then princess of Wales, (who with the king always took most extraordinary, exemplary, prudent and wise care of the health and education of their children) sent for Sir H. to ask his opinion of the inoculation of the princesses. He told her royal highness, that by what appeared in the several essays, it seemed to be a method to secure people from the great dangers attending that distemper in the natural way. That the preparations by diet, and necessary precautions taken, made that practice very desirable ; but that not being certain of the consequences which might happen, he would not persuade nor advise the making trials on patients of such importance to the public. The princess then asked him, if he would dis- suade her from it : to which he made answer, that he would not, in a matter so likely to be of such advantage. Her reply was, that she was then resolved^ it* should be done, and ordered him to go to the late King George the first, who had commanded him to wait upon him on that occasion. He told his majesty his opinion, that it was impossible to be certain but that raising such a commo- tion in the blood, there might happen dangerous accidents not foreseen : to which he replied, that such might and had happened to persons, who had lost their lives by bleeding in a pleurisy, and taking physic in any distemper, let ever so much care be taken. Sir H. told his majesty he thought this to be the same case, and the matter was concluded on, and succeeded as usual, without any danger during the operation, or the least ill symptom or disorder since. Sir H. had been consulted with on the like occasion by many, and was of opi- nion, that since it is reckoned, that scarcely 1 in ] 000 misses having it some time in their life, the sooner it is given them the better, notwithstanding the heat of summer, or cold of winter; the danger being greater from falling into the distemper naturally, than from the heat or cold of either. What he had observed, which he thought material, is not to inoculate such as have any breakings out on their faces, soon after the measles, or any other oc- casion, by which the small-pox were likely to be invited, and come in the face in greater number, and so make the distemper more dangerous. Bleeding in ple- thoras, or gentle clearing of the stomach and inte4>tines, are necessary; and ab- 4 T '2 692 VHILOSOPHICAL TRANSACTIONS. [aKWO 1755. stinence from any thing heating, about a week, before : and nothing else needful by way of preparation ; and very little physic during the course of it, unless acci- dents happen. [Then follows a description of the operation of inoculation, which at that time was very rude, and consisted in making an incision into the skin of the arm about 1 inch long, and afterwards applying a dossil dipped in the variolous mat- ter, and keeping it on for 24 hours, covered with a plaster, &c.] Of above 200 that he had advised before the operation, and looked after during it and its consequences, but one had miscarried, a son of the duke of Bridge- water, in whose family this distemper had been fatal, where the eruption of the small-pox was desperate, notwithstanding it was perfectly safe in his sister, who had undergone the same preparations, and was inoculated the same day, and with the same matter used for her brother. On the whole it is wonderful, he observes, that this operation, which seems so plainly for the public good, should, through dread of other distempers being inoculated with it, and other unreasonable prejudices, be stopped from procuring it. One thing he had observed, that though the persons inoculated were ad- vanced in years, it was equally successful as in younger persons. LXXII. Of (in Extraordinary Agitation of the Water in a small Lake at Close- burn, in the Shire of Dumfries. By Sir T. Kilpatrich of Ctoseburn, Bart. p. 52 1 . About a quarter before Q on Sunday morning, Feb. 1, 1756, we were alarmed with an unusual motion in the waters of Closebum-loch. There was first a strong convulsion and agitation of the waters from the west side of the loch to- wards the middle, where they tossed and wheeled about in a strange manner. Thence proceeded 2 large currents formed like rivers, which ran with rapidity beyond all description, nearly contrary ways, one from the middle to the south- east, and the other to the north-east points of the loch. There they were stopped short, as the banks are pretty high, and obliged to turn, which occa- sioned a prodigious tumbling and agitation at both ends of this body of water. There was likewise a current, which rose sometimes considerably above the sur- face near the west side, that frequently ran with great velocity 1 00 yards to the southward, and returning in a moment with as great velocity the other way. In the next place, there was a tossing of the waters in the ponds, which were more or less moved as the agitations of the loch came nearer this side, or kept at a greater distance from it. These agitations and currents continued, without inter- mission, for about 3 or 4 hours, when they began to abate a little in their violence, though they were not quite over at sun-set. This strange phenomenon was renewed on Monday morning a little before Q, and lasted for an hour and a half; but the motion of the water was not near so violent as the day before. There was no wind all the time. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. GQS LXXIII. Letlsrs on the Irregularities of the Tides at Chatham, Sheemess, Wool- wich and Deptford, in Feb. 1756, communicated by George Lord Anson,* F.R.S. Letter L From Mr. M. Godden. Dated Chatham-yard, Feb. 23, 1756. p. 323. Mr. G. remarks on the irregularity of the tides, having taken particular notice of them by the Lys, a French ship, having broken from her moorings 3 times in that week. The first time was on Thursday the 12th instant, at about lO in the morning, it being then about high water, or rather ebb ; so that they could not get her off that tide, but attended and hove her off the next, at about Q at night, which was sooner than expected by an hour and a half. They then put her to another mooring, and about half past 1 1 the same night, she broke from them also, and came on shore near the dock, it being then a small matter ebb, so that they could not get her off that tide, but attended her the next, till half past 1 1 on Friday morning to do it, it then being about the time of high water, but could not ; the tide being not so high by 5 or 6 feet as it was the tide before, though it should have been higher, as they were increasing. And he further took notice at the same time, that the tide was at a stand several minutes, and then flowed again near a foot in height before it ebbed, and the next tide, at half past 9 at night, they got the ship off, though they did not expect she woulcf have floated till near 1 2 : and again in transporting her up to her moorings, there was little or no tide ran from 10 to 12, which was about the time of high water ; which they greatly wondered at, as it was quite calm. All which irregu- larities he imagined to be owing to the wind, having had very hard gales for most part of that week. Letter 2, from Mr. Mic. Monasty, dated Sheerness, Feb. 23, 1756. p. 525. The day tide on the 13th instant was ver)' remarkable ; for it ebbed no more than 2 feet and a half for 4 hours after high water, when it was observed to flow again for a few minutes ; then ebbed again, but so little, that at low water, we had 7 feet water at the stern of the dock, which is 5 feet more than was ever known to be. It blew very hard in the morning on the flood, with the wind to the southward of the west, and on the ebb in the afternoon the wind abated and veered to the north-west, to which he then, in part, attributed this phenomenon, as a northerly wind forces water into this river, and always makes high tides, and a southerly wind the contrary. * The celebrated circumnavigator; he commanded the Channel fleet in 1747, when he captured 6" French men of war and 4 East Indiameii ; for which and other services he was created a peer by George II. He was afterwards appointed first Lord of tlie Admiralty, and admiral and commander in chief of his majesty's fleets. He died in 1762, aged 65. The interesting narrative of his voyage round the world was composed under his own inspection, not by his chaplain as was long believed, but by Mr. Benj. Robins. The title, which became extinct on the death of big lordship, has beea lately revived in the person of Thomas Lord Anson of Shugborough. 694 PHILOSOPHICAL TRANSACTIONS. [aNNO J 755, Letter 3, from Mr. Walter Taylor, dated Woolwich Yard, Feb. 25, 1756. p. 526. The tides the last week, and even for some days this week, have been very irregular and unusual. Feb. 9, winds, tides very irregular. Feb. 10 and 11, the same. The 12th, the night tide flowed about 2 feet 10 inches higher than the morning tide. The 13th, the night tide flowed about 3 feet higher than the morning tide. The 14th, 15th, 16th, 17th, the tides more regular. The 18th, the flood came in much sooner than usual, and seemed to flow gradually at first, but between 1 and 2 p. m. the tide flowed several feet, as on a sudden, and continued flowing till \ past 3, being some time longer than it was expected it would, and they had a high tide. The 19th, this day's flood did not hold so long by a quarter of an hour as yesterday's, and not so much water by several feet. The wind being to the westward, and a frost, greatly checked the tide. Since which, the tides have been very regular. In a 4th letter from Deptford-yard, similar irregularities were observed. LXXIV. And the same in the River, near London, by a Letter from Robert Dingley, Esq. F, R. S., dated London, March 8, 1756. p. 530. LXXV. Thoughts on the Rev. Dr. Hales's New Method of Distillation, by the United Force of Air and Fire. By William Brownrigg, M. D., F. R. S. Dated Whitehaven, Dec. 3, 1755. p. 534. In the process of distilling sea water, as described by Dr. Hales, the great in- crease of vapour raised by his method, above what is raised by the common method of distillation, may be attributed chiefly to the violent agitation of the water contained in the body of the still, by the motion of the air continually pressed through it. Though the air, by attracting the watry particles, may also contribute to produce this effect. It is however certain, that a simple mecha- nical agitation of warm water will greatly promote its evaporation, by increasing its surface, from which the vapours arise, and by putting its heated particles in a brisker motion, thus exciting between them actions and reactions, and so dis- posing them to fly off in elastic vapours. Of this we have instances in warm water, when simply stirred about in vessels, or poured out of one vessel into another ; from which the vapours visibly arise in larger quantities, than from the same water when it is not moved by such mechanical agitation. This excellent invention of Dr. Hales may probably be applied to other pur- poses, besides that which he had principally in view, viz. the distilling of sea- water with greater ease and expedition, with less fuel, and in smaller vessels, than has hitherto been practised, for the benefit of navigators. It might be of VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 6Q5 singular use, if it could be applied in the fire-engine. The great expence of large boilers in the construction of that machine, and the vast consumption of fuel in the working of it, render its uses much less extensive than they would be, could those expences be contracted. But air cannot be applied in this en- gine, to increase the quantity of the elastic steam, since it would pass with the steam from the boiler into the cylinder, and prevent a vacuum from being there produced, and hinder the piston from moving in it. A mechanical agitation of the water in the boiler of the fire-engine mav how- ever be produced by other means, so as that a larger quantity of steam may pro bably be raised, than can be effected in engines as commonly now constructed ; by which means the expences of constructing and working those useful machines may perhaps be greatly lessened. If, for example, the boiling water, instead of being agitated by air, as in Dr. Hales's method, was briskly stirred about by a wheel placed in the boiler of the fire-engine ; it is probable, that by this means the quantity of elastic vapour raised might be considerably increased, and less fuel and a less boiler might then serve the purpose. The wheel might be turned round by the water drawn up by the engine ; or might receive its motion fi-om the beam of the engine by means of a crank ; or a labourer might be employed in turning it round with the hand. But the desired effect might, in all probability, be better produced by means of elastic steam driven briskly through the boiling water. The steam of water, as an elastic fluid, possesses many of the properties of common air. Like air, when driven briskly from the aeolipile, it is observed to blow up fire ; and when forcibly driven through water, will doubtless produce the same agitation, as is done by common air in Dr. Hales's experiment ; and may probably have the like effect with air, in elevating a larger quantity of elastic vapours. In order to excite an agitation in the boiling water of a fire-engine, by means of elastic steam. Dr. B. then proposes various means for this end. He also shows how the steam from the boiler of such an engine may be greatly increased in its strength, by heating it, by causing some part of the pipe that conveys it from the boiler to the cylinder, to be kept red hot, by making it pass through a fire. LXXVI. Of an Extraordinary Motion in the fVaters in the Lake Ontario in North- America. From Governor Belcher's Lady; dated Elizabeth-town, New-Jersey, Oct. 12, 1755. p. 544. I take this opportunity to acquaint you with a strange phenomenon of the lake Ontario, where general Shirley has posted himself with 2000 men, at fort Oswego. A person lately come from the camp reports, that about a fortnight 696 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. since, that lake rose and fell 3 feet and half, 3 several times, in the space of half an hour. LXXFII. Of an Earthquake felt at the Hague, on Wednesday the \Qth of Feb. 175S. By Mom. Grovestins, Master of the Horse to his R. H. the Prince of Orange, p. 544. On Wednesday morning, 12 minutes after 8, there was a shock of an earth- quake. His chair received 5 successive shakes. The sconces in the chamber were also moved. Ten or 1 2 minutes after, he perceived a 2d shock, but not so strong as the former. The wind was s.w. Immediately after the earthquake it turned n.e. It was also felt at Maestricht and Utrecht. LXXVIII. Of the Same Earthquake felt in Holland, Feb. 18, 1756, In a Letter from Mons. Allemand, Professor of Natural Philosophy at Leyden, and F. R. S. p. 545, This article contains observations similar to the preceding one, and also re- marks that the earthquake was felt throughout the whole territories of the republic. LXXIX. Of the Earthquakes felt at Brussels; in a Letter from John Pringle, M.D., F.R.S. p. 546. By a letter, which Dr. P. received from Dr. Brady, physician to the court at Brussels, he finds they felt in that city this winter 3 several shocks of an earth- quake. The first was on the 26th of December; the 2d on the day following; and the 3d on the 1 8th of February ; being the same day it was said to be felt on our coast, between Margate and Dover ; but the hour is not mentioned. All these shocks he says greatly alarmed the inhabitants; but were otherwise attended with no bad consequences. Dr. Brady adds, that he was told by a gentleman from Liege, that the men who were at work in the coal-pits, and particularly in some of the deepest near that city, had assured him, that they heard the rumb- ling noise preceding the shock as over their heads ; while those who were above- ground heard the same kind of noise as under their feet. LXXX. On the Sinking of a River near Pontypool in Monmouthshire. By Air, Edivard Matthews, p. 547. The 1st day of January 1756, a poor woman, living near the mouth of the river, sent her daughter for water, a great flood appearing in the river just before, who returned in surprise with the account, that it was dry. The river is called by the name of Frooyd, running between two steep hills, or woods, but not very high; "t proceeds from water from the adjacent mountains, and seems penned up VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. SQ? for the most part parallel and correspondent to those of the rocks, islands, and neighbouring continents. They contain stones of different sorts, minerals, metals, various petrified bodies, pumice-stone, lavas formed by volcanos. Istria, Morlachia, Dalmatia, Albania, and some other adjacent countries, as well as the rocks, the islands, and the correspondent bottom of the Adriatic sea, consist of a mass of a whitish marble, of a uniform grain, and of almost an equal hard- ness. It is that kind of marble called by the Italians marmo di Rovigno, and known to the ancients by the name of marmor Traguriense. This vast bed of marble, in many places under both the earth and the sea, is interrupted by se- ' veral other kinds of marble, and covered by a great variety of bodies. There are discovered there, for instance, gravel, sand, and earth, more or less fat. The variety of these soils under the sea is remarkable. It is to this that Dr. Donati ascribes the varieties observed with respect to the nature and quantity of plants and animals found at the bottom of the sea. Some places are inhabited by a great number of different species of plants and animals ; in others, only some and let out precipitately, to cleanse the iron ore lying near the surface on the sides of these mountains, which greatly discolours the water, which at those times, and after heaN-y rains, is so rapid and violent, as to carry down prodigious quantities of large stones into another river called Avon Looyd. Mr. M. walked up the Frooyd on the bottom of the river, it being quite dry, up to the chasm, that now receives the water; it is about 20 feet wide; and when its banks are full, about 8 or 10 feet deep; but now filled up to 15 feet with stones carried in by the water. There is a lime-stone rock near the surface, about 2 feet thick, lying in large beds 2 or 3 feet square, more or less in some places, joined close in others. On one side of the river near this hole, are 3 pits sunk at the same time, the one within 10 yards, of which there was no appearance before; the other two at about 30 yards up the side of the hill, which have been observed, for many years, though nobody knew the cause of them, are now sunk some yards deeper, and some trees and shrubs, that were round the edge of the pits, with the ground on which they grew, are sunk down near the bottom. These pits at top are about 1 2 yards diameter, gradually narrowing to a centre, in shape of a funnel or tun-dish. Under, it is supposed, is this cavity, through which the river now runs, extending itself in one place under the river Avon Looyd, at about a mile distance, where it broke out a few days after, in several places, on the opposite side of it, where were 3 small springs. The reason for this conjec- ture is, these springs were observed to be always clear till a few days after the sinking of this rock, but now continue to send forth large quantities of this water, which varies in colour like the water received in at the hole. VOL. X. 4 U 698 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. LXXXI. On the Agitation of the /Voters, Nov. 1, 1755, in Scotland and at Hamburgh. Communicated by John Pringle, M.D.,F.R.S. p. 550. About 10 o'clock of the forenoon of Nov. 1, a gentleman at Queen's-ferry, a sea-port town on the Frith of Forth, about 7 miles higher up than Leith, ob- served the water rise very suddenly, and return again with the same motion, which he judged to be about 12 or 18 inches perpendicular, which made the barks and boats then afloat run forwards and backwards on their ropes with great rapidity; and this continued for 3 or 4 minutes, it being then calm; but after the 2d or 3d rush of water it was always less. The following phenomena are well vouched to have happened at Hamburgh, the 1st of November 1755. In one of the churches many persons, that were present, observed an agitation of the branched candlesticks hanging from the roof, about 1 in the afternoon. In another church, the cover of the baptistery hanging from the roof was also remarked to be agitated ; and the like motions are said to have happened in other churches. Also the water in the canal through the town, and in the river Alster, was agitated the same day. It is de- scribed first to have formed several gentle whirlpools, thence to have risen more and more imjjetuously, throwing about mud brought up from the bottom, and at last to have subsided with a copious white froth. The Elbe rose in some places still more violently. LXXXI I. Microscopical Observations : in a Letter from Edivard Wright, Esq. dated at Paris, Dec. l6, 1755. p. 553. It appears from the experiments of M. de BufFon and Mr. Needham, that animal and vegetable substances infused in boiling water, put into bottles com- pletely filled, and so closely stopped that no air -can enter, and even kept for 'some time in hot ashes, that in case there should be any latent ova of insects they may effectually be destroyed; yet it appears from the said experiments, that such substances, notwithstanding such precautions, afford microscopical animal- cules of various kinds, and that sooner or later, according to the greater or less degree of exaltation in the substances. Hence they conclude, that there is a real productive force in nature, by which these animalcula are formed. Having read the accounts of these experiments, Mr. W. was desirous to make some of the same kind, which he accordingly did, in the summer of the year 1752. Though the greatest part of the animal substances, on which he made any experiments, treated in the manner above-mentioned, yielded, sooner or later, great numbers of microscopical animalcules; yet most of the vegetable substances, whether from the coldness of the season, which was not very favour- able that year, or through some fault in preparing the infusion, entirely failed, and underwent a fermentation, without ever giving the smallest signs of any thing endowed with life. VOL. XLIX.] VHILOSOPHICAL TRANSACTIONS. 6qQ May 1, 1752, at 11 o clock forenoon, Mr. W. made an infusion of dried millepedes, or wood-lice, such as are commonly kept in the apothecaries' shops. These he put unhruised into a small phial, so as to make it half full; then poured on them as much boiling water as filled it neck and all, stopped it with a well masticated cork, and put it into a pocket, where it was kept in a mild degree of warmth. He let it remain till 10 o'clock the same evening, when he examined a drop of the infusion with the highest magnifier of a very good microscope made by Mr. Clarke of Edinburgh. He found the whole swarming with oblong, slender, flatfish pellucid animalcules, pretty nearly of the same breadth through- out the whole length of their bodies, and without any appearance of a tail, fig. 13, pi. 16, all evidently of the same kind, though not all of the same length and^dimensions, extremely vivid, and, as appeared, spontaneous in their motions, which they performed in all directions in an undulatory, vermicular way. Observing the speedy appearance of these animalcules, he wished to know, in how short a time they might be produced; for which pui-pose. May 3d, he made just such another infusion, putting it into his pocket, as before, and an hour afterwards laid a drop of it before the microscope, while it was as yet milk warm. He observed a very few of these minute bodies moving about briskly in the fluid. An hour after this more of them appeared ; and before the end of the 3d hour, the infusion contained a great number of them. They continued however to increase in numbers for an hour or two afterwards, when the infusion seemed to have produced all that it was capable of. June 3d, he made an infusion in the same way of unbruised cantharides, and in much about the same time found the whole swarming with animalcules of the same kind as those of the infusion of millepedes. These bodies, which at first appeared larger than those in semine masculino, were very soon decomposed into smaller ones, to speak according to the doctrine of Messrs. Needham and BufFon, or, as others would rather incline to express it, succeeded by smaller ones, these again by others still smaller, and so on, until in a few days, the highest magni- fier of the microscope could exhibit nothing distinct to the eye. The same sub- stances infused in rectified spirits of wine, or other spirits, showed none of these bodies; and a few drops of such liquors, or of a solution of fixed or volatile alkaline salts, poured into the infusions, instantly destroyed the animalcules. Mr. W. declines inquiring, whether these animalcules are produced by the decomposition of the substances in which we observe them, which, according to Mons. de BufFon contain a number of living organic particles, or, according to Mr. Needham, a vegetating force in every microscopical point, capable of form- ing secondary combinations, microscopical plants, zoophytes or animalcules, according to the greater or less degree of exaltation, which the several substances have attained. Or whether they proceed from ova formerly existing in the sub- 4 u 2 700 PHILOSOPHICAL TRANSACTIONS. [anNO 1755. stances, and capable of enduring a great degree of heat, without being destroyed, the germs of which are sooner or later developed according to the fitness of the nidus, as is the opinion of the learned and ingenious Dr. Parsons, in his treatise on the analogy between the propagation of animals and that of vegetables : as by entering into a discussion of these different sentiments, a large volume might be written without perhaps going to the bottom of the matter. Mr. W. there- fore only observes, that whichever of these opinions we embrace, thus far seems to be certain, that the earlier or later appearance of microscopical animalcules, is always in proportion to the degree of tendency to putrefaction in such sub- stances as afford them. This is the case not only with them, but likewise with maggots in meat, which every body knows are produced from the eggs of flies. The two substances millepedes and cantharides, on which the above observations were made, are very putrescent, and the infusions of them soon stunk abominably. Castor, though an animal substance, and seemingly very much exalted, treated in the same manner as the above-mentioned substances, viewed by the microscope every day, and kept for several months, afforded no animalcules, nor seemed to have undergone the smallest change ; which confirms what the inge- nious Dr. Pringle has observed, that it is antiseptic ; and adds weight to the ob- servation made above, that the appearance of such animalcules denotes a tendency to putrefaction. Hence Mr. W. thinks that such microscopical observations, made with accuracy, might be usefully applied in the investigation of the septic and antiseptic qualities of animal and vegetable substances ; since in this way the first motion of putrefaction may be discovered, before it manifests itself otherwise. Mr. W. subjoins a few remarks concerning exaltation, which seem to deserve attention. All exaltation, he observes, appears to be a certain modification of the salts and oils of bodies : a proper degree of it favours growth and vegetation, and sustains animal life : a greater degree of it, which he calls the putrefactive exaltation, and to which all organized bodies tend more or less, decomposes all such bodies, and favours the production of microscopical animalcules, or the de- velopement of the ova from which they may be hatched. A still higher degree of exaltation puts a stop to this process, as also to vegetation, and in certain cir- cumstances even to animal life, as happens with regard to all acrid chemical pre- parations, &c. whether of the animal or vegetable kingdom. Those who imagine that all salts and oils hurt the vegetating force of matter, have fallen into a great error ; for whence can such a vegetating force proceed, but from a due mixture and modification of the salts and oils with the earthy principle, which every one allows to be of itself inert ? It is true indeed, that a very large portion of salts or oils renders substances antiseptic, or very slow either of vegetation or putrefaction, as is well known with regard to sea-salt, a large quantity of which preserves substances from putrefaction ; though, as Dr. Pringle observes, a smaller one rather forwards that process, as it does likewise vegeta- VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 701 tion. Castor, which as Mr. W. formerly observed, is antiseptic, seems to owe this quality only to a large quantity of a sluggish fetid oil, which it contains. LXXXIIL On the Cure of a Paralytic Arm, by Electricity ; by Cheney Hart, M. D. p. 558. [This was a case of paralysis rheumatica, cured by electricity used conjointly with other remedies.] LXXXIV. Observations made at Guadaloupe on the Brimstone-hill, in French La Soiiffriere, in that Island. By John And. Peyssonel, M. D. Member of the R. A. of Sciences of Paris, &c. and F.R.S. Translated by Dr. Maty. p. 564. Tlie Island of Guadeloupe is not the only one of the American Antilles, that has volcanos and mines of brimstone ; few are without them ; they are found in Martinico, Dominica, St. Christopher's, St. Lucia ; all which islands produce sulphur, pumice-stones, and other substances usually found in volcanos. The mountain, on which M. P. made his observations, is called La SoufFriere, or Brimstone-hill, because it contains ores of sulphur; and its summit constantly emits smoke, and sometimes flames. It is very high, and forms a kind of trun- cated cone. It rises above the chain of mountains that occupy the centre of the island, and run through all its length from north to south. This conical moun- tain is about 3 leagues from the sea-shore, east, west, and south, and therefore almost in the middle of the southern part of the island. In ascending, it is soon observed that the woods differ in kind ; the trees are smaller, and are no more than shrubs at the top, that is, on a level with the other mountains. Here you meet with none but mountain-mangles, whose wood is crooked and bends down- wards, and their bark is a true Jesuit's bark. Having arrived at the spring-head of the river of galleons, south of the brimstone-hill, at the place called the Three Springs, the waters were so hot as not to be borne. The neighbouring ground smokes, and is full of brown earth like the dross of iron. In other places the earth is red like colcothar, and even dyes the fingers ; but these earths are taste- less. Near these 3 burning hot springs are some others, that are lukewarm, and some very cold. They put some eggs into the hot ones, and they were boiled in 3 minutes, and hard in 7- Gk)ing on, about the length of 400 paces, they began to get sight of the windward, or of the eastern coast of the island. Having passed this moun- tain of the 3 rivers, and the valley between it and the Brimstone-hill, they began to ascend the latter, where they were obliged to help themselves with their hands, feet, elbows, and knees, and to hold by the fern, aloes, and other plants, some of which were prickly, and very troublesome. They were about an hour and a half getting up to the height of about 500 feet, when they reached the gulf, at the place whence the smoke issues. This place is at the foot of a steep bank. 702; PHILOSOPHICAL TRANSACTIONS. [aNNO 1/55. and may be about 25 toises in breadth : there is no grass to be seen, nothing but sulphur and calcined earth ; the ground is full of crevices, which emit smoke or vapours ; these cracks are deep, and you hear the sulphur boil. Its vapours rising yield very fine chemical flowers, or a pure and refined sulphur. It is chiefly found in those places where the earth lies hollow, and on the chinks or funnels you see the spirit of sulphur run down like fair water, and you breathe an intolerable smell of brimstone The ground is loose, so that they could thrust their canes up to the head, and when drawn out they were as hot as if they had been plunged into lime when slacking. Hastening out of this dangerous situ- ation, they continued climbing to the top of the mountain, keeping to the east, or windward. When at the summit, they discovered another gulf or funnel, that opened some years since, and emits nothing but smoke. The top of the mountain is a very uneven plain, covered with heaps of burnt and calcined earth of various sizes ; the ground smokes only at the new funnel, but appears to have formerly burnt in many places : for they observed abundance of these crevices, and even gutters, and very large and deep chinks, which must have burnt in former times. In the middle of this flat is a very deep abyss, or precipice. It is said, there was once a great earthquake in this island, and that the Brimstone- hill took fire, and vomited ashes on all sides, and this mountain cleft in two ; when probably this abyss or precipice opened. Perhaps the volcano having been fired by lightning, the salts of the earth joined with the sulphur produced the effect of gunpowder, and occasioned this dreadful earthquake. The moun- tain having split, cast forth ashes and sulphureous matters all around, and from that time no earthquake has been felt in the island. This abyss, in the middle of the flat, is behind two crags or points, that rise above the mountain, and on the north side answers to the great cleft, which goes down above a thousand feet perpendicular, and penetrates above a hundred paces into the flat, and is more than 20 feet broad ; so that in this place the mountain is fairly split, from the top down to the basis of the cone. From the top of this mountain there is a most delightful prospect. You dis- cover below the islands of Martinique, Dominica, Marigalante, and the whole extent of Guadeloupe. Those of St. Vincent, St. Kits, and even St. Martin, are said to have been seen from the top of this mountain. Montser'-at, Antigua, Nevis, Radonde, and several other islands were very distinctly observed. The air at top is bleak and sharp, but the cold not very intense. Here the party had only time to examine the great cavern and the great cleft above it, and then with- draw to the habitation whence they came, being very weary ; for in coming down they were often obliged to slide, sometimes sitting, sometimes lying on their backs, and holding by the fern. They were often almost buried by tumbling into holes. They met with abundance of nests of black devils, a kind of sea-birds, that come from the north, and hatch their young on this mountain. TOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 703 Any quantity of brimstone might be fetched from this mountain, even ship- loads. It might be refined on the spot, or made up into lumps to be sold^ and shippetl in the ore, if necessary ; but it is too cheap a commodity to be worth gathering up in a country, where the price of labour is so high from the scarcity of hands. Bright yellow brimstone with a greenish cast might be gathered round the vent-holes of the burning gulf, also large quantities of fine natural flowers, or very pure sulphur. What passes in this mountain may be called a natural analysis and distillation. The brimstone takes fire in the centre of the earth, as in chemical operations, when the mixture of spirit of nitre and oil of turpentine suddenly produces a surprising heat and flame : in like manner an oily and sul- phureous exhalation inflames and sends forth fires, which the ignorant vulgar take for shooting or falling stars. The flowers rise with the acid spirit, which being condensed by the cool air, falls down in drops. By fixing bell-glasses to the apertures of the funnels, one might collect a spirit, that rises naturally. One of them having thrust his cane too far into one of the funnels, and not being able to pull it out again, helped himself with the blade of his sword to catch hold of it. In an instant they saw the hilt quite wet, and the water dropping off, and when he drew it out, they were surprised to find the blade extremely hot. LXXXFI. Of the Earthquake, felt Feb. 18, 1756, along the Coast of Eng- land, betiveen Margate and Dover, in a Letter from Mr. Samuel Warren. Communicated by John Pringle, M.D., F.K.S. p. 579- This earthquake happened a little before 8 in the morning. Many persons felt it by the shaking of their beds, &c. at Margate, Deal, Dover, Sandwich, gcc.} LXXXP^II. On the Stones in the Country of Nassau, and the Territories of Treves and Cologn, resembling those of the Giants-Causey, in Ireland. By Abralmm Trembley , F.R.S. From the French, p. 581. These stones were in a quarry, near Weilbourg in the country of Nassau, on the declivity of a hill; it had not been dug into above 20 feet deep, and 40 long. This quarry consists of a mass of stones of an almost regular form. He could not discover at what depth these stones extended under-ground. They appeared very near the surface of the earth, where the quarry lies. And there was a pretty considerable space of ground, in which the top of the stones appeared, and where it was easy to examine the shape of their upper ends. It is very far from being the same in all of them :, but when a number of them are comjjared with one another, we find reason to conclude, that the hexagonal form is the most com- mon. The more regular the figure of these extremities is, the more it approaches to that of a hexagon. The two ends of every stone appeared, for the most part, to have the same shape. The sides of the stone are of the same form with the ends, and are plain. Every stone is therefore a prism of a certain rjumber pf 704 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. sides. They are from 3 to 8 sides, and of all the intermediate numbers. The length of the prisms is unequal, from 2 to 5 feet long. The thickness of them is not at all more equal : it is of 9 inches and under. Many of them form a pillar by lying one upon another; all their ends and joints plain. The pillars, formed by several of those stones, are placed exactly one against the other, with- out having any void between them. They are in a situation almost perpendi- cular. On breaking these stones, their colour appears clearly to be black. It is a kind of pretty hard basaltes. It strikes fire with steel ; and it appears to be very like that of the Giants Causey in Ireland. This stone must be very common in the country of Nassau. At some leagues distant from Weilbourg, is an old castle almost entirely built of it. In going from Weilbourg to Coblentz in the electorate of Treves, he observed on the road thither, in the towns and villages through which he passed, that this ba- saltes was made use of in the buildings and pavements. He made the same re- mark in his journey from Coblentz to Cologn through Bonne. He found a pretty large heap of it in a village 3 leagues from Bonne. In continuing his journey along the Rhine, in his way to Bonne, he saw in the river, the waters being pretty low, a rock, which stood a foot or two out of the water, which was a mass of those prisms of basaltes, the heads of which appeared ; and which he concluded was the top of a natural mass of the stone. Hence he was convinced that there were quarries of it along the Rhine. In coming near Bonne, the parapet-walls along both sides of the high road, are found built of these basaltes stones. There are many of them in the old walls of the ramparts of Bonne and Cologn, and in the pavements of those cities. Some authors mention quarries of this basaltes in Upper and Lower Saxony, and in Silesia. Those who have made observations on salts, and inquiries into stones, mine- rals, and metals, know how common crystallizations are in nature. A very great variety are found in searching mountains, visiting caverns, and descending into mines. There are few of the naturalists, accustomed to these researches, who shall observe the basaltes above mentioned, but will be inclined to consider them as so many crystallizations. LXXXFIII. Account of a Work published in Ilalian by Fitaliano Donati, M.D. containing, An Essay towards a Natural History of the Adriatic Sea. By Mr. Abraham Trembley, F.R.S. From the French, p. 585. In this work. Dr. Donati examines both the earth and the sea, and even the soil under the sea, to discover their fossils and other productions. His inquiries have enabled him to determine, that there is very little difference between the bottom of the Adriatic sea and the surface of the neighbouring countries. There are at the bottom of the water, mountains, plains, vallies, and caverns, just as on the land. The soil consists of different strata placed one upon another ; and VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 705 particular species are found ; and lastly, there are other places, in which neither plants nor animals are to be met with. These observations not only point out the affinity and resemblance between the surface of the earth and the bottom of the sea ; but may likewise contribute to discover one cause of the varieties which are observed in the distribution of the marine fossils found in the earth. Dr. Donati remarked in that vast mass of marble, which is common to the bottom of one part of the Adriatic sea, and to the neighbouring provinces towards the east, a multitude of marine bodies petrified ; some of which are so united to the stony substance, that they are scarcely to be distinguished. He found in some places human bones petrified, which form one mass with a mixture of marble, red earth, and stalactites. One of the objects, which most excited the attention of our author, was a crust, which he discovered under the water in divers places, and for a great ex- tent. It is a composition of crustaceous and testaceous bodies and beds of polypes of different kinds, confusedly blended with earth, sand, and gravel. They are found at the depth of a foot or more, entirely petrified and reduced to marble. At less than a foot deep they approach nearer to their natural state. And at the surface of this crust, they are either dead, though extremely well preserved, or still living. This observation demonstrates, that stones or petrifactions may be formed, and actually are formed, in great quantities under the water. It is to be remarked, that these crustaceous and testaceous bodies and beds of polypes, are every where mingled in the utmost confusion with each other : which shows a striking resemblance between the crust discovered at the bottom of the sea, and those of the marine bodies petrified, found in many parts under the earth, and especially in Italy. If these marine bodies petrified are naturally in that confusion in the sea ; if they were born and die ; and if they have been petrified in that state ; it is highly probable, that those which are found under- ground in the strata in such confusion, are likewise placed naturally in the same manner under the sea, when it covers them, and not by means of extraordinary events, such as volcanos and earthquakes, as has been conjectured. The more these bodies and beds of polypes multiply, the more their exuviae and skeletons contribute to enlarge this crust discovered at the bottom of the sea. Dr. Donati remarked, that in several parts it formed very considerable banks, and of a very great thickness. Hence it follows that the bottom of the sea is constantly rising higher and higher. Divers other causes contribute to it. Snow and rain-waters bring down from the neighbouring mountains, into the sea, a great quantity of earth and stones. The waves, beating against the shores of the continent and islands, detach many masses, which are spread upon the bot- tom of the sea. The rivers carry the mud with their waters into the sea, at the bottom of which that mud deposits itself. From the rising of the bottom of the VOL. X. 4 X 706 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. sea, that of the level of the water naturally follows. Dr. Donati furnishes us with a great number of facts in proof of this. He observed, that at Venice, in Istria, and in Dahnatia, the level of the waters is several feet higher than it was formerly. This elevation of the waters is observed only on the northern and eastern coasts of the Adriatic. The sea seems on the contrary, to abandon the western coast, that of Italy. This Dr. Donati has showed by many very inte- resting facts. He proceeds then to the observations, which he made upon the plants and animals of the Adriatic sea. He begins with some general reflections on the nature of both. On this occasion he treats of the question concerning the re- semblance between plants and animals, and in general of the chain, which these different organised bodies form by the affinity between them established by na- ture. In mentioning the facts, which show this imperceptible transition from the class of animals to that of plants, he seems inclined to believe, that these facts are most frequently to be met with in the waters. After having given a description of several very curious marine plants, he pro- ceeds to the beds of polypes. He gives this name to all those organized bodies, known under the name of coralline bodies ; and which were, for a long time, ranged under the class of plants. He then mentions different bodies, which he calls plant-animals, and animal-plants, according to the characters which he found belonging to them, and which bring them more or less near to one or other of these general classes. dini I LXXXIX. On a Parihian Coin, with Characters on the Reverse resembling those of the Palmy renes. By the Rev. John Swinton, M- A. of Christ-Churchy Oxon, F. R. S. p. 593. Some years before, Mr. S. met with a small brass medal, in but indifferent conservation ; which he discovered, he thinks, by comparing it with others, to be a Parthian coin. This medal, he apprehends, exhibits the head of Vologeses the 3d, adorned with a beard and a tiara, after the Parthian manner, with a beta be- hind it, which seems to point out the place in which it was struck. The reverse presents a strange sort of instrument or machine, which perhaps may be imagined to represent a key, besides some traces of characters in a great measure defaced, and which he thinks are 4 entire Palmyrene letters. XC. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the Royal Society, by the Company of yfpothecaries, for the Year 17 55, pur- suant to the Direction Sir Hans Sloane, Baronet, by John Wilmer, M,D., &c. p. 607. This is the 34th annual presentation of this kind, completing to the number of 1 700 different plants. VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 707 XCI. On the Earthquakes felt at lurin, Dec. Q, 1755, and March8, 1756. Bij Dr. Fital. Dovuti, Prof, of Botany at Turin. From the Italian, p. 6l2. The cause of earthquakes is unknown to me. The ancients have observed, that earthquakes were accompanied witli some particular meteor, and some re- markable alteration in the air. Such alterations have been observed at the time of the late earthquakes. Who knows, whether an electrical force be not ca- pable of moving more than a quarter of our globe ? I have communicated this notion to father Beccaria, and I found him almost entirely convinced of it. On the 9th of December, at half an hour after 2 in the afternoon, a shock of an earthquake was felt here at Turin ; but not a considerable one, so that a great number of persons did not perceive it. For my own part I felt it very sensibly, being then in the Universitj-pulpit raised very high. The chair, on which I sat, was thrown by the shock from one side of the pulpit to the other, in the direction of south to north. This shock lasted between 4 and 6 seconds. Some minutes after came another shock, but it was extremely slight. Its di- rection was likewise from south to north. I have been informed from Milan, that about the same hour, and on the same day, a shock of an earthquake had been felt. The waters did not rise, and yet a good deal of motion was observed in those of the lakes. For 3 days the waters rose from underground in the lower apartments of the houses situated near the east gate. The springs that water the lands in the country, became more copious. On the 28th of December at 6 o'clock, according to the Italian way of reck- oning, a slight earthquake was felt at Padua. On the 8th of March, at half after 1 1 in the morning, in the French way of reck- oning, I felt 2 shocks directed from above downwards, but they were very slight. CII. Of a Continued Succession of Earthquakes at Brigue in Calais. Written by the Rector of the College of Jesuits at Brigue. From the Latin, p. 6l6. Valais, and especially Brigue, have almost every 1 0 years felt earthquakes, but never any so considerable as in 1735. For in that year, on the 1st of No- vember, which was so fatal to Portugal, we felt Brigue several times shaken, and particularly on that very day. And from that time, especially in the night, the walls were perceived by many persons to tremble ; whence they justly ap- prehended still greater shocks of an earthquake. On the gth of December, about 2 in the afternoon, the earth at first made a great noise, and seemed, as it were, to give a signal for immediately retiring. This was, not long after, fol- lowed by repeated, but sliglit motions. At a quarter after 2, the earth was again shaken, and a much louder noise heard : at last, a little before half an hour after 2, all Valais seemed on the point of destruction ; for the earth began not only to tremble, but to send forth a horrible noise, and to shake all the buildings with so violent a motion in the space of 2 pater nosters, that the houses inclined 4x2 708 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. on each side alternately, and rocked like a cradle : almost all the chimnies were thrown down ; all the churches suffered very great damage ; the towers gaped ; a considerable number of walls fell down ; and stones of all sizes poured down from all the buildings, so that no house at Brigue escaped some injury. The whole neighbourhood suffered the same calamity, especially Glisa and Natria. In th« latter, the roof of the parish church fell at the same moment ; and at Glisa, the large church, and especially the tower, were greatly damaged. For a great part of the wall of the tower being removed out of its place, fell on the roof of the church, and broke it, and demolished the side altar under it. At Brigue both the church and college of the Jesuits suffered very considerably. Part of the roof of the former fell down ; and all the walls of the college were much cracked. In some places the earth opened and immediately closed again ; and water rose from the ground several feet high. Some fountains also ceased running ; and not a few, never seen before, have flowed from that time. From the Qth of December to the 2 1 st, the shocks were repeated every day, but still fewer and less violent. On the 21st, at 4 in the morning, Brigue was «o much shaken, that every body was justly frightened : but no damage was done, except the falling down of some stones. From the 21st to the 27 th, we felt the earth moved twice or thrice every day at different times. On the 27 th, at half after 2 in the afternoon, Brigue suffered a shock almost equal to that on the Qth, but of a shorter duration, and attended with scarcely any damage. On the 28th, about 6, a. m. there were 2 slighter motions. The 29th was the first day free from disturbance. On the 30th, at one in the night, the houses were greatly shaken, so' that some chimnies, which had been before damaged, now fell. On the 2d of January, 1 7 56, at half after 9 at night, there was a slight shock. On the 3d, a little before 10 in the morning, there was another gentle one ; but none till the 6th, before 8 at night, when a pretty considerable shock happened. On the 7th, about 5 in the evening, were two more, as also on the 8th at half after 8 at night. For the 3 following days all things were quiet. On the 1 1th, at 3 in the morning, and again about 8, and on the 12th and 13th were some few shocks, but slight. On the 14th, at half an hour after 2 in the morning, every thing was put into such an agitation, as is inexpressible ; but the damage was but small, as the motion lasted but 3 or 4 seconds. On the 15th, at half an hour after 5 in the morning, there was a slight shock. It is obser- vable, that on this day, and generally for 3 or 4 hours before the earthquake, we observed a gentle trembling to precede, and the winds which were before violent, to subside of a sudden : and that the motion seemed always to be propagated from the south to the north. It is fact, that all the books in our library, though of a square form, were all thrown down from the south towards the north. I observed the same in the chasms of the ground, which were nearly pa- rallel with the meridian. I often remarked likewise, that the Rhone grew turbid VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. yOQ a little before the earthquakes ; and I frequently took notice, in the evening after sun-set, very long clouds stretched out like a straight line, without any breadth, and extended from the south to the north. The earth in some places was broken into fissures, but not large ones. The writer then goes on to state, that repeated shocks were felt, but gradually less violent, from the 1 8th of January till the end of the month ; that on the 6th and 1 8th of February violent shocks were experienced, with slight interme- diate ones; «nd that they were repeated slightly till the 26th, when they ceased. cm. Extract of a Letter of Mans, la Condamine, F. R. S. to Dr. Maty, F. R. S. Translated from the French. Dated Rome, March 11, 1756. p. 6'22. The Abbe Barthelemi, who is here, has been at Naples. In the manner of going on with the manuscripts there, it will require above a century to open and paste them all. However it is done with great dexterity. But there is only one person employed in it. The Canonico Mazzocchi, who copies them, is very capableof that task. An academy of antiquaries is just founded at Naples, for explaining all the antiquities dug up at Herculaneum ; but according to their method of discussing things in their assemblies, they will not explain 2 dozen antiquities in a year. They will alter their method, and find, that such kinds of works, and perhaps all others, are not to be done by a company. The Abbe Barthelemi has read very well a page, except a few words, which he had not time to study. The account of the manuscript on music is true. The measures of the Abbe de la Caille, and those of Father Maire and Father Boscovich do not agree with the elliptical curve of the meridian, or with the circularity of the parallels. And the earthquakes felt on the same day on all the coasts of Europe, and in Africa and America, at Ancona, Morocco, Boston, and in the Baltic, may contribute to convince those who should doubt of it, that the earth has immense cavities, and that it is very heterogeneous, or rather of a very unequal density. Consequently its figure is a little irregular ; or, if the curvature be such as the laws of statics seem to require in the hypothesis of ho- mogeneity, that figure must be altered by changes happening in the internal parts of the mass. It was at first supposed to be spherical, and the orbits of the planets were considered as circular. It was afterwards found that they were elliptical, and the earth an elliptoid. Every step made in the study of natural philosophy has discovered some apparent irregularity, according to our manner of conception. The refractions, the aberration of light, the nutation of the earth's axis have all been reduced to a calculation. Afterwards was found out the irregularity of the refractions on small eminences, which perplex astrono- mers. The heterogeneity of our globe will puzzle the mathematicians ; and earthquakes will perhaps do so more than all the rest. I have probably observed to you before, that I am convinced, that Italy was a chain of volcanos, of which 710 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755. we know only some of the links. I have found lavas exactly like that of Ve- suvius in the whole way from Florence to Naples, and in places where there was no suspicion of volcanos. All the lakes of Italy, which I have seen hitherto, exhibit traces, not to say evidences, of this. I begin to think that the whole earth is perhaps in the same case with its surface, and was thrown into the utmost disorder at some period of time, of which no remembrance has been preserved. Lazzaro Moro, a Venetian, has gone much further than I do : all the mountains, isles, and continents arose, according to him, from the bottom of the sea, by means of subterraneous fires. I never heard of his opinion till after I had formed my own conjecture, or rather verified the fact in part of the Apennine which I have passed through. I have had time only to run over the titles of his chapters. CIK. On the Currents of Sea at the Antilles. By Dr. Peyssonnel, F.R.S. p. 624. The coasts of these American islands are subject to counter-tides, or extraor- dinary currents, which render it very dangerous to chaloupes and other small craft to land ; while at the same time the boats and ships in the roads are scarcely ever sensible of them, and seldom incommoded by them ; nor do those which are out at sea appear to be affected by them. It is however certain that a regular wind constantly blows, in these parts of the torrid zone, from the tropic of Cancer, to the equinoctial line, from the east ; inclining sometimes northward, and sometimes southward. This wind is called alize, or trade-wind, for reasons admitted by philosophers, and it draws the water westward, giving a total and uni- form course to that immense quantity, which comes from the great river of the Amazons, and from an infinite number of other rivers, which discharge them- selves into the ocean. These currents passing to the westward, go up to the American islands, then to the coasts of Jucatan and Mexico, and running round in the gulf, return Into the great ocean, by the straits of Bahama, along the coasts of Florida, in order to pursue, in the north, the course ordained them by the Supreme Being. It is in this course the waters are known to nm with an extraordinary rapidity ; they pass between the great and little islands of America, in the great deeps, by an almost even and imperceptible motion ; but against the shores and coasts of these islands, which form this archipelago, these currents are very sensible and dangerous; they interrupt the navigation, insomuch that it is scarcely possible to stem these tides to get to the eastward. It often happens, that vessels steering from St. Domingo, or the other Lee- ward islands, to the windward ones, cannot absolutely accomplish it, and are therefore obliged to get out of the channel, and steer away to the northward, in order to tack up to the windward isles. These are daily observations, and well known to all navigators of America. Besides these regular currents, there are others, called counter-tides, which VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 711 are observable on the sea-coasts and shores. In places where these flow, the sea rises in an extraordinary manner, becoming very furious without any apparent cause, and without being moved by any wind ; the waves rise and open very high, and break against the shore, with such violence, that it is impossible for vessels to land. These he thinks are chiefly caused by the pressure of heavy black clouds sometimes seen hanging over an island or the sea. As to other currents in the main seas, or in other particular situations, as the gut and the coasts of the Mediterranean, Dr. P. ascribes them to the action of the winds, &c. Hurricanes are foreseen by a calm, and a frequent shifting of breezes from all points; the setting sun of a blood-red; little clouds moving with great rapidity; the sea-birds, called frigates, and many other kinds, quit the air, and seek the shore. By these signs, together with the season in which these happen the hurricanes are expected; proper precautions are then taken to avoid the fury of the winds; the houses are propped, the windows and doors are barred up, and papers and other valuable moveables are secured in chests. Soon after, a north breeze springs up, which comes to the north-east, and from south to south-east; the air is darkened by one continued thick cloud, which increases the horrors of the night ; for it often happens, that these tempests come in the night, and con- tinue all the next day. In the last hurricane he saw, the wind stood at north- east, and blew with such violence, that the largest trees were torn up by the roots, their trunks broken to pieces, and not a leaf left on those other trees which yielded to the fury of the winds , the houses were thrown down, and the tops of the sugar-mills, which are conical, and less susceptible of being thrown down, were crushed to pieces ; scarcely any thing remained standing on the ground. These ftirious winds were accompanied with a violent rain, which resembled the mist made by the agitation of waves, or like waters kept up by the wind. The tempest lasts till day-light, and sometimes continues pretty far in the day. In that in 1740, towards 8 o'clock in the morning, it grew suddenly calm for a quarter of an hour, and then returned again blowing from the south, with such violence, that the buildings and trees, which were destroyed by the north wind before, were blown about, and moved by the first blast of that from the south. At the end of these there appears lightning, and we hear the noise of thunder : these are the signs of the tempest's being at an end ; for the wind softens gra- dually, and all becomes quiet. After these hurricanes the forests appeared only like a parcel of ship-masts or poles standing ; all the trees being stripped of their leaves', and their branches broken off^ made a dreadful appearance, especially in these countries, where a perpetual verdure adorns the trees and fields. Every one is employed in repair- ing his losses, and mending the dismal remains of the frightful wreck. 712 PHILOSOPHIC AL TRANSACTIONS. [aNNO 1755. XCV. Of the Lacerta (Crocodilm) ventre marsupio donato, faucibm Merganseris rostrum cemulantibus.* By Mr. George Edwards, p. 639. What is most extraordinary in this species, and distinguishes it from all other crocodiles, is the narrowness of the beak or chaps, which appears like the bill of the bird called a goosander (merganser). It has small sharp teeth, of which he says no more, as he has given 3 very exact views of the head and beak ; see fig. 14, pi. 16. Another particularity is a pouch or open purse in the middle of the under side of the belly, which seems to be naturally formed, with round lips and a hollow within, perhaps to receive its young in times of danger; as we find it in the American opossum. The opinion of Dr. Parsons too was, that the opening in the belly was really natural, it having no appearance of having been cut or torn open. In other respects it has all the marks common to alligators and crocodiles, viz. a particular strong square scaliness on the back, which in the young ones appear distinct and regular, but in the older ones lose their dis- tinct form, and become knobbed and rough, like the bark of an old tree; and in having small, round, and oval scales on their sides, which in the young ones are no larger than rape seeds; and the belly is scaled, to appearance a little like the laying of bricks in a building. It has fins on the outsides of its fore and hinder legs, as other crocodiles have. It has also a great distinguishing mark of the crocodile kind, viz. two rows of fins on the upperside of the tail, which be- gin insensibly small at the setting on of the tail, and increase gradually as they advance toward the middle of it, where they become one row, and so continue to the end. The tail is roundish at its beginning, but from the middle, where the two rows of fins become one, it is flat like an oar. The fore feet have each 5 toes, the hinder feet only 4; which is also a mark of the crocodile; all the lesser lizards having 5 toes on each of their hinder feet. In the fore and hinder feet, the 3d and 4th toes only are webbed together. The eyes are very promi- nent. The head is covered with several large scales. The beak is finely creased transversely. As I have been very exact, says Mr. E. in my figure, which was worked on the copper-plate immediately from nature by my own hand, and in several different views, it will express more than can easily be conveyed by words. It appeared in the spirits all over of a yellowish olive colour, the underside lighter than the upper ; the upperside having some dusky marks and spots, as repre- sented in the print. This species Mr. E. believes, when at full growth, to be near, if not quite, as large as the common crocodile. * This species is the lacerta gangetica, Linn. Gmel. It grows to a larger size than the Nilotic crocodile, and exclusive of the long and narrow form of the snout, it has nearly double the number of teeth : the specimen here described was so young as to have the opening of the umbilical vessels still remaining : otherwise it has no particular ventral cavity, as erroneously imagined by the author. END OF VOLUxME TENTH. C. and R. Baldwin, Printer*, New Bridge-itreet, London , 1 Vol.X. Fhilos. Ti-ans. ri.2. Uiuttr MxJIf^i (if Vc-I. X. Fhilos. Trans. Fi.n. I IBidim ^> AyMI AT Vol.X. Fhilos. Traju. J%.M. 1^.1 ^ €> The wnmwn ■feal/ The TortPUff headed Seal'. Mkttw .rc.lt^fiMitT vu.x. Philos. Tmns. PI. IT. F,y.7. Fiy.2. Fi^. 8. Fi0. 10. Fl^.M. • 1 t Fig. 9. Fig.S. Fi0.1. Fy.n. Fy.lS. Fig. 3. Fy.n. Fig.n. Fy.lS. Fig U. MiattwSe.JlagMl thf rubU^hal by C kR.Bu^wuutf IfewMndgt Sthcer.iimdon.ito6. -<*i^rv va.x. Thilos. Trans. JPl.V. ^fadrr;p0ra/. JAOfr.'it.t^itUaf VU.JT. ThUos. Trans. ii.n. Pig. 5. rig. 4^. , riff .6 Fi^.5. fuctiom pi^ VA. X. 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