Sporerse beagtedreest sens tekereleisssbeds 3) eb pps bene wymsuns evens wae PORTE SES DSRS Des 3 | pebscactierp soy isa seratiesea tesels niet ii i rittesnts Seas! itstetiets Pitt seretaes breesats ; canter ies phot Serepene +t . set iy oti { t bs eteree ei tes oh S8e8tieber : jist ; 3 +f srirerictrnitty paisa tate " Kh fe : Bisset ish Hank inna “iit b : i t i peshantitpsetteet este tee < t Viet wit : at “4 oti iat Git ates ait Ht : ' Tress Arar sy oe. + So fTesete: Be ry 1] # : i 7 AY ite 3 ieee s v bots Re Th Hi 4 ' Witt | | | : | : ta It i nh | ri | oy hi. ; 3 it if it (ty a JOURNAL NATURAL PHILOSOPHY, CHEMISTRY, AND oT i Me BES Be VOL. VI. Gllustrated with Enaravings: ——— ‘BY WILLIAM NICHOLSON. SSS “ LONDON: PRINTED BY W's STRATFORD, CROWN-COURT TEMPLE-BAR FOR THE AUTHOR, No. 10, SOHO-SQUARE; | AND SOLD BY G. anp J. ROBINSONS, PATERNOSTER-ROW. =: Se > 1803. Ae es | amuile’? ineeotg ait ial aga, igh? Towonis.: ; tisha 4 ai tie: aniwil: Ms? nits big ober Me Apodiad a wud bay 2 A. iT: ed oe ‘5 new ystasr: E Hodis tees cides’ ry Pt Ww E + ot Bt se r ee aM asta Moot Bal eet nswoH arbi x a GM soul ap de adinibey engi iG oS yyewto) aw ayiatod ie Aine 3 t rons Tama! td oor, ) dosnt - aabusti pet Pe) i oe eis wing Me Holliavel cial ony - seth oe Httlosaist ale crust « | Ai patie? Problmgatae mee rov * Laeger coders Hf eee ay re haa Sieticobsl? “tak 2A a y «oH ane boars wo NG Seale: tac ie pat perranrsd » eg tow ayer mV": ide Raton Ob tele iat “eB RA hell bedsigad Hee : “vie W enn} oy Re hy oe 4 pac. moan ae “in aD ‘eat Sa a sille¥ i SOBRE ¢ wack ALS 2 4 b peaai ate so Bee 2 Be aut. ite die’ weccriagede Seg ie mee of ‘cue ati 1st bes Mh Ae eet Ra ners 49) es eee sd woke ieee i SOD) | ees OE? Coated “ches vs nae y ak 2 & Lt ; et Oe 5 Ag * hate Mais pea 7 y * * + ~ e socsacs fod a ee ute : ane att oF snirged.e On gs i ta ass IMs pit “ie Saat ban: atts me Oe ar (Cy ae at es “y . x XY Ssinsialebl ; Ab ue @ tei boitoets er Sts: oie 8 9s zwenban). % ae a eteis YF oni a tb bi ae oF onl wt Ras, a, bis a, a fine: Jorn giaaer oth ee Be ADVERTISEMENT. ‘Tur Authors of Original Papers in the present Volume, are Mr. Frederick Accum; Mr. Irwine ; Sir. A. N. Edel crantz; Dr. T. C. Hope, F. R. S. Edinburgh ; Anthony Carlisle, Esq.; M. B. Donkin; Mr. Ezekiel Walker; Thomas Thompson, M.©.; Dr. Boftock; Mr. Dalton ; Edward Howard, Esq. F. R. S.; Mr. A. Woolf; Andrew Duncan, M.D. F. R. S. Edinburgh; Dr. Prince ; Mr. J. C. Hornbiower, and Mr. G. Smart. Of Foreign Works, M. Regnier; Wiegleb; Guyton; Curaudau ; Baunach ; Payffé; Parmentier; Steinacher; Schaub; Nicolai; Bouillon la Grange; Klaproth; Lomet; Tromfdorff; Seguin; Ritter Thenard ; Vauquelin; La Place; Guyton-Morveau ; Von Hombolt; Raymond; Berthollet, and Haffenfratz. And of English Memoirs abridged or extracted, Wm. Her- schell, L. L. D. F. R. S.; Richard Chenevix; Esq. F. R.S. and M. R.T. A.; aikeehty Davy, Esq.; Wm. Hyde Wel- laston, M.D. F.R.S.; Sir H. C. Englefield, Bart. F. R.S.; James Smithson, Esq. F.R.S. P.R.1.; Mr. James Woart ; William Fairman, Esq.; Charles Hatchett, Esq. F. R. 8.5 The Right Hon. C. Greville, F. R.S.; Mr. John Dalton; Everard Home, Esq. F. R. S.; and Andrew Duncan, ues M.D. F. R. 8. Edinburgh. Of the Engravings the Subjects’ are, 1. Dr. a: Apparatus for illustrating the Doctrine of Preponderance. 2. Apparatus for Experiments with Spouting-Fluids. 3. A Lock of Combination by M. Regnier. 4. Solar Phenomenon obferved, by Sir H. Englefield, Bart. 5. Figure to fhew the Proportion of the magnified Images of the fame Star at different Times, by Dr. Herschel]. 6. Sir A. N. Edelcrantz’s Method of Raifing Water in Worm*Tubs, Condensers, &c. 7. Eudiometric Apparatus, by Dr. Hope. 9. Veffel for In- closing ADVERTISEMENT. closing Anatomical Preparations, and other Objects. 9. Cry- stal of Electrical Calamine. 10. Curaudau’s Furnace fo, evaporating by a regulated Economical Heat. 11. Mr. Woart’s Method of fupporting decayed Timbers in Build- ings. 12. Mr. Fairman’s Method of extreme Branch-Graft- ing. 138.Cit. Lomet’s Addition to the Sextant for meafuring Vertical and Oblique Angles at the fame Inftant, from an _ Air Baloon, for Military Service. 14. An Apparatus. for drying Precipitates, and for Processes of Congelation, by Mr. Accum. 15. Hydraulic Combination for rendering the Atmospheric Pressure effective in Raising Water in Worm, Tubs, by Edward Howard, Esq. F. R.S. 16. Improve- ment in the Syphon, by the same. 17. A Rotatory Apparatus, by which the Power of a Steam-Engine is equalized without a Fly, and the Work may be stopped, or fet off in any Part of the Stroke, by Mr. A. Woolf. 18. Improvement in — Mr. Ezekiel Walker’s Reflecting Quadrant, by the Inventor, 19, A new Steam Valve, which indicates the Strength, and, without Attendance, regulates the Emission of Steam from a Boiler, by Mr. A. Woolf. 20. Mr. George Smart’s Ma- chine for Sweeping Chimnies without Climbing Boys. 21. An improved Chemical] Furnace. 22. Two Views of the Great Fiery Meteor which appeared Noy. 13. 1803. Soho Square, December, 1804. ea ee 8 CoCon re NL TO THIS SIXTH VOLUME. SEPTEMBER, 1803. Engravings of the following Objeéts; 1. Dr. Young’s Apparatus for illuftrating the Doétrine of Preponderance; 2- Apparatus for Experiments with Spouting Fluids; 3. A Lock of Combination, by M. Regnier; 4. Solar Phenomenon obferved by Sir Henry Englefield, Bart. 5. Figure to fhew the Proportions of ~ the magnified Images of the fame Star at different Times. By Dr. Hertchell; 6. Sir A. N. Edelerantz’s Method of eafily raifing Water in Worm ‘Tubs, - Condenfers, &c. 7, Eudiometric Apparatus, by Dr, Hope. I. Experiments and Obfervations on the Compound of Sulphur and Phof- phorus, and the dangerous Explofions it makes when expoled to Heat. By Frederick Accum, Praétical Chemift and® Teacher of Chemiftry. Com- municated by the Author. - ». ~ - - 4 - - 1 IJ. Obfervations of the Tranfit of Mercury over the Ditk of the Sun; ‘to which is added, an Inveftigation of the Caufes which often. prevent the proper AStion of Mirrors. By William Herfchell, LL.D. F.R.S. 8 I1I. Obfervations on the Chemical Nature of the Humours of the Eye. By “Richard Chenevix, Efq. F. R. S. and M. R. 1. A. - - - 2} 1V.°A Letter from Mr. Irvine concerning the late Dr. Irvine, of Glafgot, his Doétrine, which afcribes the Difappearance of Heat, without Increate of Temperature, to a Change of Capacity in Bodies, and that of Dr. Black, _which fuppofes Caloric to become latent by chemical’ Combination with Bodies; with particular Remarks on the Miitakes of Dr. Thompfon, in his Accounts of thefe Doétrines. + - - - - - - 25 v..An Account of fome Experiments and Obfervations on the conftituent ~ Parts of ‘certain Aftringent Vegetables; and on their Operation in ‘Tan- “ning. By Humphry Davy, Efq. Profeflor of Chemiftry in the Royal Infti- tution. - - - = - “ - - - - - 31 Vi. An eafy Method of raifing Water for the Purpofes of Refrigeration in | Diftilleries, Steam Condenfers, &c. By Sir A. N. Edelerantz; communi- cated by the Inventor. ey = - - - - - - 41 VII. Defcription of a new Padlock of Security with Combination. By Citi- zen Regnier. - = - - - - - - yet: 43 VIII. Obfervations on the Quantity of horizontal Refraétion ; witha Method of meafuring the Dip at Sea. By William Hyde Wollafton, M.D.F.R.S. 46 1X. An Account of Two Halos, with Parhelia. By Sir H. C. Englefield, Bart. F. R. S. - - : z - _- - 54 X. A Defcription of Dr. Young’s Apparatus for illuftrating the Doétrine of Preponderance, with an Account of an Experiment on the Velocity of Water flowing through a Vertical Pipe. eh PY = - - - - 56 XI. Account of a fimple Eudiometric Apparatus conftruéted end ufed by Dr. T. C. Hope, F. R. S. Edinburgh. : Shige sc aie a1 Mink Gl Scientific News, 62.—Combuftion of Metals in non-refpirable Gales, by means of Galyanifm - - - - - - - - - - - ib. OCTOBER, _ ii EON TENTS: OCTOBER, 1803. Engravings of the following Obje&s: 1. Veffel for inclofing Anatomical Prepa- rations and other Objects; 2. Cryftal of Eleétrical Calamine. ' By James Smithfon, Efq. S. Curaudau’s Furnace for Evaporating by a regulated econo- mical Heat; 4. Mr. Woart’s cheap Method of fupporting decayed Timbers in Buildings ; 5. Method of extreme Branch Grafting, By Wm. Fairman, E({q. I. Analyfis of the Egyptian Heliotropium, a Mineral lately imported from that Country. By Frederick Accum, Praétical-Chemift, and Teacher of Che- miftry. Communicated by the Author. - m4 - - 65 II. Method of clofing wide mouthed Veffels intended to be kept from cem- municating with the Air. In a Letter from Anthony Carlifle, Efq. 68 IlI. Extraét of a Letter from Toulon to General le Vavafleur, Infpeétor of the Materials of the Guns of the French Navy, on the Changes which Caft Iron undergoes by remaining long in the Sea. - : 710 IV. On the Antiquity of the Invention of Gun-powder, and its firft Applica- tion to Military Purpofes.. By Mr. Wiegleb. - - - 71 V. A Chemical Analyfis of fome Calamines. By James Smithfon, Efq, F.R.S.P.R.I. From the Philofophical Tranfactions for 1803. - ~~ 74 VI. Table of the Radii of Wheels, from Ten to Three Hundred Teeth. The Pitch being two Inches. By Mr. B. Donkin, Millwright, Dartford, Kent. 86 * VII. Account of the Pyrometer of Platina. By Citizen Guyton. - 89 VIL. Letter from Mr. Ezekiel Walker on the Proportion of Light afforded by Candles of different Dimenfions. - - = us £ 90 IX. On the Compounds of Sulphur and Oxygen. By Thomas Thomfon, , M.D. Leéturer on Chemiftry in Edinburgh. From the Author. 92 IX. Further Experiments and Cbfervations on the Effervefcences of Walls. In a Letter from Dr. Boftock. - - - - ~~» 109 X. Philofophical Obfervations on the Caufes of the Imperfetion of evapo- rating Furnaces, and on a New Method of conftruéting them, for the eco-- nomical Combutftion of every Defcription of Fuel.. By C. Curaudau, corref- ponding Member of the Pharmaceutic Society of Paris. . 114 XI. Correction of a Mittake in Dr. Kirwan’s Effay on the State of Vapour in the Atmofphere. By Mr. Dalton. - z c g t18 XII. Cheap and. effeétual Method of fecuring Beams of Timber in Houfes or elfewhere, which have been injured by the Dry Rot, or are decayed by Time. By Mr. James Woart. - - f s 120 XIII. Account of the Method of extreme Branch Grafting. By the Inventor William Fairman, Efq. - b ss rs e ah 194 XIV. Obfervations on -feveral Pharmaceutical Preparations, by Cit. Stein- acher, Druggift at Paris. Abridged by Citizen Parmentier. ~ 130 Scientific News, 184.—Extract of a Letter from Dr. Schaub to Mr. Parkinfon, ib.—-Meteoric Stones, 155.—Abftract of a Memoir on the Febrifuge Principle of Cinchona, 136.—Query by a Correfpondent refpeéting the Auguftine Earth, 139.—Spaniard faid to refift high Degrees of Heat and {trong chemi- cal Agents, 1b.—Method of giving Malt Spirits the Flavour of Brandy, 140, —Preparation of a Lute proper for Chemical Operations.. By C. Payfle, ib.—« Two new Quadrupeds, 141.—Prefervation of Iron from Ruf = - ~— 142 Account of Books, 143.—Philofophical Tranfagtions of the Royal Society ‘of London, forthe Year 1803, Part I. 143.—An Effay on the Law of Patents for new. Inventions ; to which are prefixed Two Chapters on the general Hiftory of Monopolies; with an Appendix, & i 144 NOVEMBER, , * CONT £ BTS. itt NOVEMBER, 1808. Engravings of the following Objeéts; 1. Mr. Woart’s Method of fecuring Tum- ~ bers which have been injured bythe Dry Rot; 2. Cit. Lomet’s Addition to the Sextant for meafuring vertical and oblique Angles at.the fame Inftant from ¢n Air Balloon, for Military Service; 3. Apparatus for drying Precipitate, and for Proceffes.of Congelation. By Mr. Accum; 4. Hydraulic Combination for rendering the Atmofpheric Preflure effective in raifing Water in Worta Tubs. By Edward Howard, Efqg. F. R.S. 5. Improvement in the Syphon. By the fame; 6. Rotatory Apparatus, by which the Power of a Steam Engine: is equalized without a Fly, and the Work may be flopped or fet off in any’ Part of the Stroke. By Mr. A. Woolf; 7. Improvement in Mr. Ezekiel} Walker’s Reflecting Quadrant. By the Inventor, I. Experiments aud Obfervations on the various Alloys, on the Specific Gras vity, and on the comparative Wear of Gold. Abftracted fram the Memoir of _ Charles Hatchett, Efq. F. R. S.in the Philofophical Tranfactions for 1803. 144 II. A Memoir on the Appearance of Speétres or Phantoms occafioned by Dif. eafe, with Pfychological Remarks. Read by Nicolai to the Royal Society of Berlin, on the 28th of February, 1799 = z = 16] II. Analyfis of Ambergris; by Cit. Bouillon LaGrange - - 179 IV. An Account of fome Stones faid to have fallen on the Earth in France; and of a Lump of native Iron, faid to have fallen in India. By the Right Hon, Charles Greville, F.R.S. - - > - - - 187% ¥. Analyfis of the Natrolite. By Klaproth - - - 19% VI. On the Employment of Aeroftatic Machines in the Military Science, and for the Conftruction of Geographical Plans. By Cit. A. F. Lomet 134 VIE. Chemical Analyfis and Properties of Arfeniated Hidrogen Gas, By Pro- feffor Trom{dorff - - - - - - 208 ~ VIII. Account of an Eudiometric Apparatus, contrived and ufed hy Dr. Hope, Profeflor of Chemiftry in the Univerfity of Edinburgh ~~ 210) 1X. Defcription of an Apparatus for drying the Produéts of Chemical Analyfis, which is alfo ufeful for Experiments of Congelation. By Mr. Fiederick Accum. Communicated by the Inventor - - - 212 X. Letter from Mr. Accum, in anfwer to the Enquiries of a Correfpondert refpecting the Procefs for obtaining the Agufine Earth - 214 XI, Letter from a Correfpondent concerning the Method propofed by Mr. Carlifle for clofing wide-mouthed Veffels - - - 21h XIE. Account of an Experiment fer fupplying Worm Tubs and other Refrigera+ tories by the affiftant Preilure of the Atmofphere, which proved unfuccefs- ful, on a large Scale ; to which is added an Improvement for extending the ufeful Application of the Syphon, By Edward Howard, Efq.F.R.S. Ina Letter te the Editor - - - -. - - 216) XIII. A Method of equalizing the Motion of a Steam Engine without the Affiftance of a Fly Wheel. By Mr. Arthur Woolf, Engineer, Communi- cated by the Inventor - - - - - - 218 XIV. Improvement by which the’additional Arc in Mr. Ezekiel Walker’s re-' | flecting Quadrant is rendered unnecéflary. In a letter fromthe Inventor 219 Scientific News, 221,~-Abftra&t of Cit. Seguin’s Inquiries concerning Fermen- tation, ib.—Additional Experiments of Mr. Ritter, of Jena, on Galvanic Phe- nomena, ib.—Abftraé&t of fome Remarks on the Acetite of Lead, by Cit. Thenard, 223.—The Arachis Hypogea, or Ground Nut of the Welt Indies, cultivated in France for its Oil = - ae - 224 DECEMBER, iv _ SONTENT 5. DECEMBER, 18053. Engravings of the following Objects: 1. A. new Steam Valve which indicates the Strength, and without Attendance, reculates the Emiffion of Steam from 4 Roiler. Communierted by Mr. A. Woolf the Inventor; 2. Mr. G. Smart’s Machine now in daily Ufe for Sweeping Chimnies, without Climbing Boys; 3. Improved Chemical Furnace; 4. Two Views of the great Fiery Meteor, which appeared Nov. 15, laft. 3, Letter from Andrew Duncan, M. D. F.R.S. E. containing Experiments and Ob{ervations on Cinchona, tending ae scm to shew that it does not contain Gelatine - - - - 225 II. Letter from a Correfpondent, containing Dilspuiitoasiy on the Phantafins of Nicolai, and other Derangements of the : Animal Syftem. - 229 JIT. Experiments on the Subltance valeeey called Gum Kino. By Cit. Vauquelin =e WV. Extract of a Taree from Dr. Piigee cemuettine ie Aig-Pump. 235 VY. Memoir on the Tides. By Cit. Lapiace : 239 VI. Abftrac&t of a Paper by Cit. Guyton-Morveau, paeiled an Examination of a native Carbonate of Magnefia. - - 4 a 240 VII. Curious Particulars reipecting the Mountains and Volts and the Ef- fe& of the Jate Earthquakes in South America, with Remarks on the Lan- guage and ree of the fprie and other ak eae BY, M. A. Von Hom- boldt. - 242 VIH. Method of meafuring any Aliquot Part of an Tact by a Sarit which gives no fuch Part in its Turn ; and Obfervation on an Error of Edwards in placing the Eye- Step of refleéting Meleiooues. In a Letter from Mr, J. C. Hornblower. - 247 7X. Account of a new ‘Aptian cuaiiructed die the Pie oF meafuring the Elaftic Force, and regulating the Emiffion of Steam from the Boiler in which it is generated. Communicated by the is innit Mr. Arthur Woolf, En- gineer. = - 949 X. Journey. to re pitas of Mont- Bardy By Cit. Bamtad, 250. XI. Notice of a Method of giving the Apres of Cotton to Hemp or Flax. By Cit. Bertholiet. 252 XII. Defcription of a Machine now in cata cant daily “Ute, for cleanfing Chimnies, without the Affiltance of Climbing-boys, and with much greater Effect than is produced by that Method. Communicated by the Inventor, Mr. Chriftopher Smart, of Ordnance Wharf, Weftminger Bridgee W.N. 255 XU. Experimental Eilays on the Contiution of mixed Gafes; on the Force of Steam or Vapour from Water and other Liquids in different Temper- atures, both ina Torricellian Vacuum and in Air; on Eveporais and on the Expanfiou ot Gales by Heat. By John Dalton. = 2571 XIV. Delcription of the portable Furnace conitrusted by Dr. Black, and fince improved. Ina Letter from Mr. Accum. 3 A 273 KV. Obfervations on the Stru&ture of the Tongue; {lluftrated by Cafes in which a Portion of that Organ has been removed ey Ligature. BY Everard Heme, Fig. F.R.S. — - - 216 XVI. Some Acci unt oF the large ne Mtbor ilies appeared on the 13th of lat Month (November) 279 XVI. A Firft Memoir om Coloured Ghedows By Cit. Je Halfeatiaee: 282. Scientific News, 286.—Ohbfervations on St. John’s Wort. By Cit. Baunach, ib. Account of New Books, 288.-~The Edinburgh New Difpen{atory: containing, 1. The Elements of Pharmaceatacal Chemiftry ; ; 2. The Materia Medica; or, the Natural, Pharmaceutical, and Medical Hittory of the different Subftances employed in Medicine; 5. The Pharmaceutical Preparations and Compofitions, &c. By Andrew Duncan, Jua. M. D, Fellow of the Royal College of Phy- ficians, and Royal Society of Edinburgh, and Affociate of the Linnzan So- ciety of London : = & ‘- - = Ib, . a A JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, AND THE AR PS, SEPTEMBER, 1803. ART LE Lyf, Experiments and Objervations on the Compound of Sulphur and Phofphorus, and the dangerous Explofions it makes when exr- pofed to Heat. By FrepertcK Accum, Practical Chemift and Teacher of Chemifiry. Communicated by the Author. Marcrarr, I believe, was the firft who noticed the Compound 6f combination of phofphorus and fulphur; and Pelletier See ane ; , g fulphur; when amined afterwards this compound, and pointed out fome of fir examined. its properties *, The latter philofopher thowed, at leaft, that the compound refulting from the union of phofphorus and fulphur, in different proportions, is infinitely more fufible than either of them taken feparately. Repeating the experi- ments of the French philofopher, I had no apprehenfion that not fuppofed to the combination of thefe two fimple bodies was attended, go auenaee with under certain circumftances, with confequences which might prove fatal to the chemical operator. And it is with the view of preventing my brother chemifts from falling a facrifice to unexpected dangers, that I fhall relate an accident, which might have been attended with-the moft dangerous con- fequences, before I ftate the properties which charaéterife the compound which is the fubjeét of thefe lines. The ac- * Journal de Phyfique, xxxv. 383, Vor. VI.—SertemBEeR. B cident ‘ 2) COMPOUND OF SULPHUR AND PHOSPHORUS. Very dangerous cident alluded to, happened ‘in the following manner. Half ri panents sae an ounce of phofphorus, cut into pieces of the fize of a pea, of half an ounce was introduced into a Florence flafk, containing about ten eee ounces of water ; one ounce of fulphur broken into fragments water andone Of about the fame fize was added, and the whole placed on a ounce of fulphur heated fand-bath, In a few minutes the union of the phof- on a fand heat. ; ; phorus and fulphur was effeéted. On leaving the whole in the heated fand, for about,ten minutes longer, the empty part of the flafk became filled with denfe white fumes, which in- creafed more and more ; being unable to obferve what change was taking place, I carefully removed the flafk out of the fand-bath, and agitated the fluid in fuch a manner, that the fufed compound of phofpnorus and fulphur ftillremained under the furface of the water. But the inftant this was done, the whole exploded in my hand with a tremenduous report; the mixture of the burning phofphorus was. thrown into my face, and occafioned very painful wounds; the pieces of the Florence flafk were {cattered all over the laboratory, as fine as fand, and the larger parts of the neck of this veffel were driven into my right hand, as well as into the wall, to a confiderable depth. Repetition of Anxious to underftand the nature of this unexpeéted ex- ee te aaa plofion I again expofed to heat, in a fimilar manner, two alfo with larger drachms of phofphorus and half an ounce of coarfely powder- asa gee ed fulphur, in a fmall flafk containing four ounces of water. plofion asbefore. Lhe mixture, after having been left in a heated fand-bath for about ten minutes, exploded with prodigious violence, and a flafh of fire rofe up to the ceiling. The fame experi- ment was repeated with larger quantities of phofphorus and fulphur, three fucceflive times, with fimilar effeéts. Thefe experiments were made at the laboratory, and in the prefence of the Right Honourable Lord Camelford, who liberally fupplied the materials for thefe and the following experiments, _ and permitted them to be made on his premifes, Another ac- Before I advance any thing further concerning the accenfion Be. of this compound, I beg leave to relate one inftance more of nature. a fimilar nature, which happened lately inmy own laboratory, Mr. Garden, a philofophical gentleman immerfed into a veffel filled with warm water, a vial containing fix ounces of phofphorus, to which had been previoufly added one drachm of a mixture of phofphorus and fulphur. The contents of the G@OMPOUND OF SULPHUK AND PHOSPHORUS. g the vial being liquified, (which was the intent of immerfing it into heated water) he removed the vial out of the fluid, taking care to clofe its orifice with his finger, and then agitated it gently. The moment this was began the vial burft to pieces with a report like a gun, the burning mixture was thrown in all dire@tions, and the whole laboratory was filled for fome hours with a very denfe cloud of white vapours. Being thus fufficiently convinced of the danger which attends Careful ape i the combination of phofphorus with fulphur, under fuch cir- eer cumftances, I introduced into a Wedgwood’s tube clofed at Phofphorus, +1. sulphur and one end, two drachms of phofphorus, and double that quantity “YP akon of fulphur. I then added four ounces of water, and clofed difttlation. the other extremity of the tube with a cork, into which a bended tube was cemented, which terminated under a glafs cylinder filled with mercury, ftanding inverted in a bafon containing the fame fluid. I then reclined the tube, and applyed heat to that part which contained the phofphorus and fulphur; on increafing the heat gradually'a quantity of gas forded a gas i without exolae was collected, which amounted to nearly two quarts. But <... : no explofion took place. To learn the nature of this gas, I transferred a quantity of which, added te it into the water apparatus, and agitated it in contaét with jj 700 2) that fluid ftrongly for a few minutes. Its volume was now fluid ; confiderably diminifhed. On repeating the experiment in diftilled water, it was found that this fluid abforbed nearly 4 of its own bulk. On fending up one part of atmofpheric air but took fire into a cylinder holding fix parts of this gas, an inftantaneous we oa inflammation enfued, the cylinder became filled with white mon air was fumes, and a white cruft lined the inner furface of the glafs. added to.a larger ues of the gas. Finding thus that the gafeous product was decompofable by atmofpheric air, I colleted another quantity of gas, in a fimilar The refidue of manner as before; and mingled it gradually with oxigen ‘his 82s decom- : > pofed by oxigen gas till no further accenfion enfued. The gas left behind was azote. amounted to 25 of the whole. It had all the properties of nitrogen gas. The white flakes which were colle&ted from the fides of the The precipitates glafs cylinder, as well as from the furface of the mercury over ('"; alphas - 4 E i ulphuric, and which the experiments were made, attracted moifture rapidly, phofphoric acide. and became converted intoa cream-like fluid. They confifted of fulphur, fulphuric and phofphoric acids. B2 Oxigenated 4. COMPOUND OF SULPHUR AND PHOSPHORUS. Oxigenized muriatic acid gas acted more violently than oxigen gas, when mingled with this gafeous compound over mercury; the refult was a confiderable detonation, accom- panied with vivid green light and denfe white vapcurs. , The gas was From the refults of thefe experiments it becomes obvious, therefore a com- that the gas under examination was a compound of hydrogen, Pound Re fulpl d phofphorus. And if we reafon’ from the nature gen, fulphur, {ulphur, and phofphorus. nd if we reafon from the nature and phofphorus;of the produétion of this gas, it is evident, that, during the aétion of the phofphorus\and fulphur upon water, the latter formed by the fluid is decompofed, though neither fulphur nor phofphorus decompofition of - 5 + -— . wus tid ete Par : ari es fingly taken, can effeét this decompofition ; this therefore is that fluid is not fufficient to account for the unexpected explofion before affected by either Aa tod fingly. ; Phofphuret of In order to fee whether phofphuret of fulphur were capable fulpbur can de- of decompofing water in common temperatures, two ounces compofe water ie . : : 3 at the common 0f it were covered in a vial with eight ounces of water, and temperature. put afide for further examination. The vial having been left unobferved, locked up in a clofet, for fome weeks; the corks was found to have been thrown out of the vial, and the whole infide of the clofet, which had been painted with white lead, was completely blackened ; the parts neareft to the orifice of the vial had a metallic afpeét, The fluid which was decanted from the phofphuret of fulphur had a milky appearance, its odour was like that of water firongly impregnated with ful- phurated hidrogen ; its tafte was uncommonly naufeous, It had a ftrong aétion on the greater number of metallic oxides. On mingling it with concentrated nitrous acid, a confidera- ble precipitate enfued, which after being dried on expofure to air, was luminous in the dark and became converted into fulphur. Another quantity of the water which was fuffered to evaporate, fpontaneoufly depofited cryftals of a lemon yellow colour, but of an indeterminate figure. ‘Phere re- mained, therefore, no doubt but that phofphuret of fulphur is capable of decompofing water at ufual temperatures, As phofphuret — Phofpburet of fulphur, compofed of three parts of phofphorus of fulphur de~ compofes airwith and one of fulphur, has.alfo the property of decompofing at- greater rapidity mofpheric air with great rapidity. It may, therefore, be pone aN employed more advantageoufly for eudiometrical proceffes be a good eudio- than either phofphorus, or the fulphurets of earths, alkalies, metrical agente or metals. If into a dry glafs tube clofed at the top, and graduated - COMPOUND OF SULPHUR AND PHOSPHORUS, 5 graduated. into equi-diftant parts, a quantity of phofphuret of fulphur, freed from adhering water, be poured, and agitated in the tube, fo as to line a confiderable part of it within, a vaft quantity of white vapour is produced the moment the tube is immerfed in water; fo as to exclude the air. The vapours will be abforbed by the water, and when no further clouds appear, the procefs is at an end. ’ The refiduary gas will then be found to be the quantity of nitrogen gas, which was contained in the air experimented upon in the tube, This procels is far more expeditious than the flow combuftion of phofphorus. I muft, neverthelefs, remark, that phofphuret This phofphuree of fulphur Like all other fubjfances hitherto employed for IR eudiometry, cannot be .abfolutely depended upon for af- tion of changing certaining the abfolute quantity of oxigen, contained in a the refidue. given portion of atmofpheric air. For as foon as the abforp- tion of oxigen is compleated, the remaining nitrogen exercifes an aétion upon the phofphorus, by means of which its bulk becomes increafed. From a number of experiments made with that’ view with this eudiometrical fubftlance, I am led to The change is believe that the volume of nitrogen gas, never increafes fo tae <4 much as to 7 part; confequently the bulk of the refiduum, diminifhed by 4; gives us the bulk of the nitrogen gas of the air examined; which bulk fubtraéted from the original mafs of air, indicates the proportion of oxigen gas contained in it. Phofphuret of. fulphur of the above compofition alfo de- This phofphuret compofes nitrous acid with uncommon rapidity at common ks temperatures. If one part of phofphuret of fulphur be in- rapidly, troduced in the cold into four or fix of concentrated nitrous acid, a violent aé@tion takes place, the acid is decompofed, and both the phofphorus and fulphur are oxigenized, at the expenfe of the oxigen of the nitric acid. A clear folution is obtained, from which phofphoric and fulphuric acid may be feparated in the ufual manner. Phofphuret of fulphur is foluble in expreffed or fat oils, Mit eee us one part of this compound, freed from adhering moifture as Hs mes * ; much as poffible, be triturated ina Wedgwood’s mortar, with fix parts of oil of almonds or olives, a liquid phofphorus is obtained, which is far fuperior to that produced in the ufua] manner from mere phofphorus. This liquid phofphorus fhines and gives a very fine liquid phofphorus, with a beautiful yellow light. It may be rubbed over the face, hands, &c. without injury, a 6 COMPOUND: OF SULPHUR AND FHOSPHORUS, ~ injury, provided the fluid be perfeéty tranfparent, and con- fequently contains not a particle of phofphuret of fulphur me- chanically fufpended. \ Which is un- The luminous property of this liquid phofphorus is fo con- commonly lu- ¢ derable, that about 40z. of it, when contained in a common ih a fize wine decanter, gives a fufficient light to difcern objects at a confiderable difiance ina largeroom, the moment the decan- ter is unftopped. Beautifulex- | Equal parts of this liquid phofphorus and oil of turpentine, ae * when agitated together and poured out of any convenient per-— shower. forated veffel; exhibits a beautiful phenomenon, greatly re- fembling a luminous rain, or fhower of fire. Caution againt = =Though a liquid phofphorus may be obtained, as direéted ee before, no attempt fhould be made to apply heat to a mixture of phofphuret of fulphur. For an explofion was always the refult whenever I attempted any procefs of that kind. Phofphuret of —§ = Phofphuret of fulphur is foluble in fulphuric and nitric ether, ee If either of thefe fluids be fuffered to ftand for fome weeks, over a quantity of phofphuret of fulphur in a clofed vial; part Luminous phe- of the compound becomes diffolved inthe ether. If the ether eee be fuffered to evaporate fpontaneoufly, or when aflifted by heat, a multitude of exceedingly fmall cryftals are left behind, which fhine in the dark with a brilliant yellow light. A piece of cloth dipped into this ether appears luminous in the dark all over, but in a few minutes this luminous appearance ceafes, and the whole appears to be fprinkled over with gems. If a feather, or piece of tow, be dipt in water, and then thrown into a bottle containing ether impregnated with phofphuret of fulphur; at the moment of contaét of the two fluids, a fudden light of a yellow colour f{preads through the air, undulates along the furface of the fluid, and illuminates the whole bottle. — Phofphuret of | Phofphuret of fulphur is foluble in pure or re@tified oil of Saga turpentine, oil of rofemary, oil of lavender, and in the reft of other volatile the volatile oils met with in commerce. The folutions are all oils. luminous in the dark, and depofit the phofphuret of fulphur when flowly evaporated, in the form of needlé-fhaped cryftals. Sparingly in Highly reétified alcohol takes upa fmall quantity of phofphuret alcohol. of fulphur, the alcolic folution is decompofable by the addition of water. It takes fire in hofphuret of fulphur takes fire fpontaneoufly in oxigenized — ox. mur. acid os muriatic acid gas, If afmall quantity of dry phofphuret of ful- phur COMPOUND OF SULPHUR AND PHOSPHORUS. 7 phur be introduced into a metallic fpoon, and then immerfed in a bottle filled with oxigenized muriatic acid gas; the com. pound inftantly kindles and burns with great vividnefs. The refults of this experiment of courfe are phofphoric, fulphuric, and muriatic acids. Phofphuret of fulphur, when in a ftate of inflammation burns When already alfo in nitrous gas, and in gafeous oxide of nitrogen. ) pe aes If a piece of cotton be impregnated with phofphuret of ful- nitrous gas and phur, and then furrounded with wool or tow, and placed un- peep 6s der the receiver of an air-pump, the compound fhines with a Combuttion in beautiful yellow light, which increafes in proportion as the air pre snie is more rarefied, On re-admitting a {mall portion of air, Deana: beautiful Corona or Aurora Borealis pervades the receiver. [f performed on a thermometer be included into the cotton containing the phof- mac aks We phuret of fulphur, it rifes in proportion as the light increafes, and in this refpeét, as well asin the former, the phofphuret of fulphur anfwers better for this experiment, which was firft no. ticed by Van Marum, who made ule of phofphorus. The formation of phofphuret of fulphur feems not to be at- No heat is de- : We veloped when tended with any change of temperature, as is {aid to be always the combination the cafe in all chemical combinations whatever. For if the of phofphorus ‘phofphorus and fulphur be immerfed in heated water, at a dif. pe ea * tancé from each other, together with a thermometer, no in- creafe or decreafe of temperature could be obferved by means of the moft delicate inftrument. The compound of phofpho- Itis more poi- rus and fulphur aéts more violently in deftroying animal life, teas than phofphorus alone. A cat which had eaten two grains of phofphorus repeatedly without impunity, died within half an hour after having {wallowed one grain of phofphuret of ful- phur. Old Compton-Street, Soho, Auguft 16, 1803, II. Obfervations Mercury neatly defined. Great magnie fying power not fuitable to the fun. TRANSIT OF MERCURY, II. (Concluded from Page 304. Vol. V ) Objfervations of the Tranfit of Mercury over the Dyk of the Sun ; to which is added, an Inveftigation of the Caufes which often prevent the proper Aétion of Mirrors.. By Wittiam HER- seurn; LLiD.fy ROS: Wirs a 10-feet refleGtor, and magnifying power of 130, I faw the corrugations of the luminous folar furface, up to the very edge of the whole periphery of the difk of Mercury. 10" 27’. When the planet was fufficiently advanced towards the largeft opening of the northern zone, I compared the in- tenfily of the blacknefs of the two objeéts; and found the difk of Mercury confiderably darker, and of a more uniform black tint, than the area of the large opening, 10" 32’. The preceding limb of Mercury cuts the luminous folar clouds with the moft perfeét fharpnefs ; whereas, in the’ great opening, the defcending parapet, down the ipa fide, was plainly vifible. It fhould be remarked, that the inftrument here applied to the fun, with the moderate power of 130, is the fame 10-feet reflector which, in fine nights, when direéted to very minute double ftars, will fhow them diftin@ly with a magnifier of 1000. Having often attempted to ufe high magnifiers in viewing the fun, I withed to make another trial; though pretty well affured I fhould not fucceed, for reafons which will appear hereafter. With two fmall double convex lenfes, both made of dark green glafs, and one of them having the fide which is neareft the eye thinly fmoked, in order to take off fome light, I viewed the fun. Their magnifying power was about 300; and I faw Mercury very well defined; but that complete diftinétnefs, which enables us to judge with confidence of the condition of the obje& in view, was wanting. With a fingle eye-glafs, {moked on the fide towards the eye, | and magnifying 460 times, I alfo faw Mercury pretty well defined; but here the fun appeared ruddy, and no very mi- pute objeéts could be perceived, 11" TRANSIT OF MERCURY. i 9 11" 28’, The planet having advanced towards the pre- Obfervations of ceding limb of the fun, it was now time to attend to the ap- the contacts. pearances of the interior and exterior contacts. 11" 32’. 10-feet reflector. The whole difk of Mercury is as Not the leat fharply defined as poffible ; there is not the leaft appearance 18" 1 any of any atmofpheric ring, or different tinge of light, vifible about Mercury. about the planet. 1)" 37’.. Appearances remain exaétly as before. 11 42’, The fharp termination of the whole mercurial difk, appears to be even more ftriking than before. This may be owing to its contraft with the bright limb of the fun, which, having many luminous ridges in the northern zone, is remark- ably brilliant about the place of the planet. 11* 44’, I was a few moments longer writing down the At Pt Ee above than I fhould have been, to fee the interior contaét fo ae eels completely as I could have wifhed; however, the thread of the fun’s limb light on the fun’s limb was but juft breaking, or broken; but eee ant no kind of diftortion, either of the limb or of the difk of Mer- cury, took place. | The appearance of the planet, during the whole time of its nor daring the - paeeive from the fun, remained well defined, to the Te a a aft. The following limb of Mercury remained fharp till it reached the very edge of the fun’s difk ; and vanifhed without occa- fioning the fmalleft diftortion of the fun’s limb,: in going off, or fuffering the leaft alteration in its own figure. As foon as the planet had quitted the fun, the ufual appear- ance of its limb was fo inftantly and perfeétly reftored, that not the leaft trace remained whereby the place of its difappearance could have been diftinguifhed from any other adjacent part of the folar difk. It will not be amifs to add, that very often, during the tranfit, No figns of I examined the appearance of Mercury with a view to its” culate Meare figure, but could not ‘perceive the leaft deviation from a fphe- rical form; fo that, unlefs its polar axis fhould have happened to be fituated, at the time of obfervation,; in a line drawn from the eye to the fun, the planet cannot be materially flattened at its poles, OBGERVATIONS 10 The attion of reflecting tele- {copes is very different at dif- ferent times. Whether moif- ture in the air impedes the action of tele- fcopes. TRANSIT OF MERCURY. OBSERVATIONS AND EXPERIMENTS RELATING TO THE CAUSES WHICH OFTEN AFFECT MIRRORS, SO AS TO PREVENT THEIR SHOWING OBJECTS DISTINCTLY. It is well known to aftronomers, that telefcopes will at very - differently at different times. The caufe of the many difap- pointments they may have met with in their obfervations, is however not fo well underftood. Sometimes we have feen the failure afcribed to certain tre- mors, as belonging to fpecula; and remedies have been pointed out for preventing them. Not unfrequently again, the tele- fcope itfelf has been condemned ; or, if its goodnefs could not admit of a doubt, the weather in general has been declared bad, though poffibly it might be as proper for diftinét vifion as any we can expect in this changeable climate. The experience acquired by many years of obfervation, will however, I believe, enable me now to affign the principal caufe of the difappointments to which we are fo often expofed. Unwilling to hazard any opinion that is not properly fupported by faéts, I fhall have recourfe to a collection of occafional ob- fervations. ‘They have been made with fpecula of undoubted goodnefs, fo that every caufe which impeded their proper ac- tion muft be looked upon as extrinfic. I fhall arrange thefe obfervations under different heads, that, when they have been related, there may remain no difficulty to draw a few general conclufions from them, which will be found to throw a con- fiderable light upon our fubjeé. Moifture in the Air. (1.) O€tober 5, 1781. I fee double ftars, with 460, com- pletely well. The air is very damp. (2.) Nov. 23, 1781. 15" 30’, The morning is uncom. monly favourable, and I fee the treble ftar Cancri, with 460, in high perfeétion. The air is very moift, and intermixed with paffing clouds. (5.) Sept. 7, 1782. I viewed the double ftar preceding 12 Camelopardalis,* with 932, In this, and feveral other fine nights which I have lately had, the condenfing moifture on the tube of my telefcope has been running down in ftreams ; which proves that damp air is no enemy to good vifion. * See Phil. Tranf, Vol. LXXV. Part I, page 68; II. 53. (4.) Dec, ‘TRANSIT OF MERCURY. J] - (4.) Dec. 28, 1782. 17° 30’. The water condenfing on my tube keeps running down; yet I have feen very well all night. I was obliged to wipe the objeét-glafs of my finder almoft continually. The fpecula, however, are not in the leaft affeéted with the damp. The ground was fo wet that, in the morning, feveral people believed there had been much rain in the night, and were furprifed when I affured them there had not been a drop. . (5.) Feb. 19, 1783. I have feen perfeétly well till now * that a froft is coming on; though Datchet Common, which is juft before my garden, is all under water; and the grafs on which I ftand with my telefcope is as wet as poffible. (6.) Feb. 26, 1783. All the ground is covered with {now ; yet I fee remarkable well. {7.) March 8, 1783. The common before my garden is all under water; my telefcope is running with condenfed vapour ; not a breath of air ftwring. I never faw better. | (8.) Auguft 25, 1783. My telefcope ran with water all the night. The fmall fpeculum, which fometimes gathers moifture, was never affeéted in the 7-feet tube, but was a little fo in the 20-feet. The large eye-glaffes and objeé-glaffes of the finders, required wiping very often. I faw all night re- markably well. Fogs. (9.) O&. 30, 1779, It grows very foggy, and the moon is Whether fogs furrounded with ftrong nebulofity ; neverthelefs, the ftars are oe a very diftiné, and the telefcope will bear a confiderable power. tele{copes. (10.) Auguft 20, 1781. It is fo foggy that I cannot fee an objeé at the diftance of 40 feet; yet the ftars are very diftine in the telefcope. By an jive of the fog, « Pifcium can no longer be feen by the eye; yet, in the telefcope, it being dou- ble, I fee both the ftars with perfeét diftinétnefs, (11.) Sept. 6, 1781. A fog is come on; yet I fee very well. (12.) Sept. 9, 1781. There is fo ftrong a fog, that hardly a ftar lefs than 30° high is to be feen ; and yet, in the tele- {cope, at great elevations, I fee extremely well. * The time is not marked in the journal; but, from the number of the obfervations that had been made during the night, it muft have been towards morning. (13.) March Whether froft be an impedi- ment to diftinét vifion by tele- fcopes. TRANSIT OF MERCURY, (13.) March 9, 1783. It is very foggy; yet in the telee fcope I fee the flars without aberration, and they are very bright. « Serpentarii is without a fingle ray. (14.) April 6, 1783. A very thick fog fettles upon all my glaffes; but the {pecula, even the 20-feet, which has fo large a furface, remained untouched. I fee perfeétly well. Froft. (15.) Nov. 15, 1780; five o’clock in the morning. An excellent {peculum, No. 2, will not aét properly; the frofty morning probably occafions an alteration in its figure. An-- other fpeculum, No. 1, aéts but indifferently, though I have known it to fhew very well formerly in a very hard froit: for inftance, November 23, 1779, I faw with the fame mirror, and a power of 460, the vacancy between the two flars of the double ftar Caftor, without the leaft aberration. (16.) O&. 22, 1781. Froft feems to be no hindrance to perfect vifion. The tube of my 7-feet telefcope is covered with ice; yet I fee very well. (17.) Nov. 19, 1781. It freezes very hard, and the ftars, even thofe which are 50° high, are very tremulous. I fufpeét their apparent diameters to be diminifhed ; and, if I recolleé& right, this is not the firft time that fuch a fufpicion has occurred to me. (18.) Jan. 10, 1782. My telefcope would not aét well, even at an altitude of 70 or 80 degrees. There is a ftrong froft. (19.) Jan. 31, 1782. I cannot fee with a power of 460, the flars feem to dance fo unaccountably, and yet the air is perfectly calm : even at 60 or 70 degrees of altitude, vifion is impaired, (20.) Feb, 9, 1782. That froft is no hindrance to feeing well is evident ; for, not only my breath freezes upon the fide of the tube, but more than once have I found my feet faftened to the ground, when I have looked long at the fame ftar. (21.) OG. 4, 1782. It froze very feverely thisnight. At firft, when the froft came on, I faw very badly, every object being tremulous; but, after fome time, and at proper altitudes, I faw as well as ever. Between five and fix o’clock in the morning, objects began to be tremulous again ; occafioned, I fuppofe, by the coming on of a thaw. (22.) Jan, TRANSIT OF MERCURY. 13 ‘ (22.) Jan. 1, 1783. I made a number of delicate obferva- tions this night, notwithftanding, at four o’clock in the morn- ing, my ink was frozen in the room; and, atabout five o’clock, a 20-feet {fpeculum, in the tube, went off with a crack, and broke into two pieces. On looking at Fahrenheit’s thermo- meter, I found it.to ftand at 112. (23.) May 6, 1783. It freezes, and in the telefcope the flars feem to dance extremely. Hoar-froft. (24.) Nov. 6, 1782. There isa thick hoar-froft; yet I fee Hoar froft ; its extremely well. It feems to enlarge the diameters of the ftars ; ae be buat, as I fee the minuteft double ftars well, the apparent en- largement of the diameters muft be a deception. (25.) Dec. 22, 1782. There is a ftrong hoar-froft: gather- ing upon the tubes of my telefcopes ; but I fee very well. . Dry Air. (26.) Dec. 21, 1782. The tube of my telefcope is dry, Dry air inimical and I do not fee well. bs talbott hes ; by telefcopes. (27.) April 30, 1783. The ftars are extremely tremulous * and confufed ; the outfide of the tube of my telefcope is quite dry. Northern Lighis. (28.) Sept. 25, 1781. There are very firong northern Northern lights lights; their flafhing does not feem to interfere with tele- 4° 2°t fem to ‘ 4 y impede vifion by feopic vifion; but all objeéts appear tremulous, and indif- telefcopes. ferently defined. (29.) Aug. 30, 1782. There are very bright northern lights, in broad arches, with white ftreaks; yet I fee perfeétly well. (30.) March 26, 1783. An Aurora Borealis is fo bright, that » Herculis, which it covers, can hardly be feen; yet, in - the telefcope, and with a power of 460, I find no difference. I compared the ftar with y Coronz, which was ina bright part of the heavens, and in the telefcope they appeared nearly alike. I fufpeéted » Herculis te be fomewhat. more tinged with red than it fhould be; and examined it afterwards, when clear of the Aurora: it was indeed lefs red; but, as it had gained more altitude, the experiment was not decifive. : Windy 14 TRANSIT OF MERCURY. Windy Weather. Wind impairs (31.) Jan. 8, 1783. Itis very windy. The diameters of the effect of the ftars are ftrangely increafed, even thofe at 60 and 70° of telefcopes. altitude. Every ftar feems to be a little planet. (32.) Jan. 9, 1783. Wind increafes the apparent diameters of the ftars. (33.) Sept. 20, 1783. The night has been very windy ; and I do not remember ever to have feen fo ill, with fuch a beautiful appearance of brilliant ftar-light. Fine in Appearance. Weather appa- (34.) May 28, 1781, The evening, though fine in ap-+ 1S Saag pearance, is not favourable. No inftrument I have will aé properly. The wind is in the eaft. (35.) Auguft 30, 1781. The ftars appear fine to the naked eye, fo that I can fee « Lyrz very diftinétly to be two ftars ; yet my telefcope will fhow nothing well. There are flying clouds, which, by their rapid motion, indicate a difturbance in the upper regions of the air; though, excepting now and then a few gufts of wind, itis in general very calm. Ata diftanee there are continual flafhes of lightning, but I can hardly hear any thunder. (36.) Sept. 14, 1781. I fee very fmall ftars with the naked eye; but the telefcope will not aé fo well as it fhould. (37.) Sept. 24, 1781. The evening is apparently fine; but, with the telefcope, I can fee neither n Corone nor Bootis double ; nor indeed can I fee any other ftars well. Over a Building. Vicinity of a (38.) Auguft 24, 1783. I viewed « Bootis with 449,737, building renders ang 910, but faw it very indifferently. The ftar was over a the ftars indif- ting; houle. (39.) O@. 26, 1780. « Bootis being near the roof of » houfe, I faw it not fo diftin€ly as I could wih. The Telefcope lately brought out. Recentexpofure (40.) O&. 10, 1780. 6° 30’. Having but juft brought out of the telefcope lake itowall & well does notafford. M™MY telelcope, it will not act weil, diftin&nefs. 6" 45’, The tube and fpecula are now in order, and per- form very well. | 2 (41.) Jan. TRANSIT OF MERCURY. 13 (41.) Jan. 11, 1782, To all appearance, the morning was very fine, but ftill the telefcope, when firft brought out, would not a& well. After half an hour’s expofure, it performed better. Confined Place. (42.) July 19, 1781. 13°15’. My, telefcope would not aét A confined place well; and, fuppofing the exhalations from the grafs in my Prevents tele- {copes from garden to affe& vifion, I carried the telefcope into the ftreet, aéting well. (the obfervation was made at Bath,) and found it to perform to admiration. (43.) July 19, 1781. My telefcope aéted very well; but a flight field-breeze fpringing up, and brufhing through the ftzeet where my inftrument was placed, it would no longer bear a magnifying power of 460. Hazinefs and Clouds. (44.) Sept. 22, 1783. The weather is now fo hazy, that Remarkable the double ftar 3 Cygni is but barely vifible to the naked 2 Seay gees This has taken off the rays of the large ftar, fo that I now fee the fmall one extremely well, which at other times it is fo dif- ficult to perceive, even with a magnifying power of 932. (45.) Auguft 13, 1781. A cloud coming on very gradually upon fixed ftars, has this remarkable effeét, that their apparent diameters diminifh gradually to nothing. (46.) July 7, 1780. The air was very hazy, but extremely calm. I had Aréturus in the field of view of the telefcope, and, the hazinefs increafing, it had a very beautiful effect on the apparent diameter of this ftar, For, fuppofing the firft of One caufe of the the points *, to reprefent the magnitude when brighteft, 15 el faw it gradually decreafe, and affume, with equal diftin€tnefs, ars, the form of all the fucceeding points, from No. 1 to No. 10, in the order of the numbers placed over them. The laf magnitude I faw it under, could certainly not'exceed two- tenths of a fecond; but was perhapslefs than one. This leads to the difcovery of one of the caufes of the apparent magnitude of the fixt ftars, | * Thefe points will be inferted in one of the plates in our next number. N. Focal 16 TRANSIT OF MERCURY. Focal Length. Obfervations in (47.) Nov. 14, 1801. The focal length of my 10-feet sae! mh ‘eS mirror increafes by the heat of the fun. I have often obferved of the fpeculum this before; the difference, by feveral trials, amounts to 8 = by hundredths of an inch. | (48.) Dec. 13, 1801. The focal length of my 10-feet mirror, while I was looking at the fun, became fhorter, con- trary to what it ufed to do; but, there being a ftrong froft, I guefs that the objeét metal grows colder, notwithftanding its expofure to the fun’s rays. (49.) Nov. 9, 1802. 10° 50’. The focus of my 7-feet glafs mirror became 18 hundredths of an inch fhorter, on being ex- poled for about a minute to the fun. The figure of the {pe- culum was alfo diftorted; the foci of the infide and outfide rays differing confiderably, though its curvature, by obferva- tions on the ftars, has been afcertained to be ftriétly parabo- lical. 12°0, The fame mirror, expofed one minute to the action of the fun, became 21 hundredths fhorter in focal length. The focus of a 10-feet metalline mirror, when expofed one. minute to the fun’s rays, became 15 hundredths of an inch longer than it was before. (50.) January 9, 1803. When I looked with the glafs 7- feet mirror, feveral times, a minute or two at the fun, it fhort- ened generally ,24, ,26, and ,30 of an inch, in focal length. The obfervations which are now before us, appear to be fuflicient to eflablit the following principle; namely, General prin- «That in order to fee well with telefcopes, it is required ciple. Uniform that the temperature of the atmofphere and mirror fhould be temperatures an is icy» Aerie ; moifture in the uniform, and the air fraught with moifture.” air are requifite This being admitted, we fhall find no difficulty in account- a li ing for every one of the foregoing obfervations. This doerine If an uniform temperature be neceflary, a froft after mild applied to, weather, or a thaw alter froft, will derange the performance of our mirrors, till either the froft or the mild weather are fufi- ciently fettled, that the temperature of the mirror may accom~ apeen etnies modate itfelf to that of the air. For, till fuch an uniformity of teeperature; with the open air, in the temperature of the mirror, the tube, the eye-glafies, and I would almoit add the obferver, be ob- tained, we cannot expeét to fee well. See obfervation 15, 47, 18, 19, and 23, But YRANSIt OF MERCURY, 17 Bat, when a froft, though very fevere, becomes [ettled, the mirror will foon accommodate itfelf to the temperature; and we fhall find our telefcopes to aét well. See obfervation 16, 20, 21, 22, 2%, and 25. _ This explains, with equal facility, why no telefcope juft or of expofure ; brought out of a warm room can a properly. See obferva- tion 40 and 41. Nor can we ever expedi to make a delicate obfervation, obfervations with high magnifying powers, when looking through a door, °™ 4 confined ‘ piace 5 window, or flit in the roof of an obfervatory ; even a confined place, though in the open air, will be detrimental. See obfer- vation 42 and 43. It equally thows, that windy weather in general, which-muft windy weather ; occafion a mixture of airs of different temperatures, cannot be favourable to diftin@ vifion. See obfervation 31, 32, and 33. » The fame remark will apply to Aurore Boreales, when they aurorze boreales ; induce, as they often do, a confiderable change in the tempera- ture of the different regions of air. See obfervation 28. But, fhould they not be accompanied by fucha change, there feems to be no reafon why they fhould injure vifton. See obs fervation 29 and 30. The warm exhalations from the roof of a houfe in a cold the roof ofan night, muft difturb the uniformity of the temperature of a {mall houfe 5 f portion of air; fo that ftars which are over the houfe, and at no confiderable diftance, may be affected by it. See obfer. vation 38 and 39. Sometimes the weather’ appears to be fine, and yet our tele- weather anpae fcopes will not a& well. . This may be owing to drynefs occas tently fines fioned by an eafterly wind; or to a change of temperature, arifing from an agitation of the upper regions of the atmofphere. See obfervation 34 and 35. Or, poflibly, to both thefe caufes combined together, See obfervation 36 and 37. If moifture in the atmofphere be neceflary, dry air cannot be proper for vifion. See obfervation 26 and 27. © And therefore, on the contrary, dampnefs, and hazinefs of damps, haze; the atmofphere, muft be favourable to diftin@ vifion. See obfervation 1, 2, 3, 4, 6, and 8. Fogs alfo, which certainly denote abundance of moifture, fogs SCs muft be very favourable to diftinét vifion. See obfervation 9, 105 1, 12, 13, and 14, Vor. VI.—SerremsBer, C Nay, 18 Experiments on the change of focal length in mirrors: by heat. TRANSIT OF MERCURY. Nay, if the obfervatory fhould be furrounded by water, we need be under no apprehenfion on that account. Perhaps, were we to ereét a building for aftronomical purpofes only, we ought not to objeét to grounds which are occafionally flooded ; the neighbourhood of a river, a lake, or other generally called damp fituations. See obfervation 5 and 7. It is however poffible, that fogs and hazinefs may increafe to {uch a degree as, at laft, to take away, by their interpofition, all the light which comes from celeftial objeéts ; in which cafe, they muft of courfe put an end to obfervation ; but they will neverthelefs be accompanied with diftiné vifion to the very laft. See obfervation 44, 45, and 46. We have now only the four laft obfervations to account for. They relate to the change of the focal length of mirrors in folar obfervations, and its attendant derangement of the foci of the different parts of the refleGting furface; and, as fimplicity is one of the marks of the truth of a principle, I believe we need not have recourfe to any other caufe than the change of tem- perature produced by the aétion of the folar rays that occafion heat; which will be quite fufficient to explain all the pheno- mena. But, in order to fhow this in its proper light, I fhall relate the following experiments. Wis Experiment. I placed a glafs mirror, of 7-feet focal length, in the tube belonging to the telefcope; and, having laid it open at the back, I prepared a ftand, on which the tron ufed in my expe- riments on the terreftrial rays that occafion heat (fee Phil. Tranf. for 1800, Plate XVI. Fig. 1.) might be placed, fo as to heat the mirror from behind, while I kept a certain objeét in the field of view of the telefcope. Having meafured the focal length, and alfo examined the figure of the mirror, which was parabolical, the heated iron was applied fo as to be about 23 inches from the back of the glafs mirror. The confequence of this was, that a total confufion in all the foci took place, fo that the letters on a printed card in view, which before had been extremely diftin€t, became inftantly illegible. In 15 feconds, the focus of the mirror was fhortened 2,3 inches; in half a minute, 3,47 inches; and, at the end of the minute, I found it no Jefs than 4,59 inches fhorter than it had been before the application of the hot iron. On TRANSIT OF MERCURY, 19 On repeating the experiment, but placing the heated iron no pyperiments on more than 2 of an inch from the back of the mirror, its focal the chan&¢ of length, in 12 minute, became 5,33 inches fhorter. I tried ail a more moderate heat; and, placing the iron at 3 inches from the back, the focus of the mirror fhortened in one minute 2,83 inches. A thermometer placed in contaé ail the refleGting furface of the mirror, could hardly be perceived to have rifen, during the time in which the hot iron produced the alteration of the focal length. 2d Experiment. Every thing remaining as before, I fufpended a fmall globe of heated iron in front of the mirror, at one inch and a half from its vertex ; and, in two minutes, the focus was lengthened 5,3 inches. The figure of the mirror. was alfo deranged ; fo that the letters on the card could not be diftinguifhed. I made a fecond trial, with the fufpended iron a little more heated, and brought it as near the furface of the mirror as I judged it to be fafe; fince a contaét would probably have cracked the mirror. In confequence of this arrangement, the focus lengthened, in one minute, 1,64 inch. On removing the heated iron, the mirror returned, in one minute, to within ,18 inch of its former focal length; and, at _ the end of the fecond minute feemed to be nearly reftored. But _ the difagreement of the foci of the different parts of the re- fle€ting furface might be perceived for a long time afterwards, and caufed an indiftinétnefs of vifion, which plainly indicated that, under fuch circumftances, the magnifying power of the telefcope, 225, was more than it ought to be, in order to fee well. 3d Experiment. I now changed the glafs mirror for a metalline one; and, on placing the heater near the back of it, the focus of the fpecu-< lum, in 30 feconds, became ,77 inch fhorter. But, conti- nuing the obfervation, inftead of fhortening ftill farther in the next 30 feconds, it became ,3 inch longer, fo that, at the end of a minute, it was only ,47 fhorter than before the approach of the hot iron. C2 4th Expe- focal length in mirrors by heats 20 Experiments on the change of focal length in TRANSIT OF MERCURY. 4th Experiment. When the fmall heated globe of the 2d experiment was fufpended in front of the mirror, the focus lengthened ,27 inch "mirrors by heat. in one minute; nor would the lengthening increafe by leaving the hot iron longer in its pofition. The foci in this, as well as in the 3d experiment, were fo much injured that they could not be meafured with any precifion ; and it was evident, that high magnifying powers ought not to be ufed with a mirror of which the temperature is undergoing a continual change. I repeated the experiment with the iron nearly red hot; and found the focus lengthened 1,48 inch in $0 feconds. Five minutes after the removal of the iron, the regularity of the figure of the mirror was pretty well reftored. With a moderate heat, I had, in 30 feconds, a lengthening of the focus, of ,57 inch; and, in about 14 minute after the removal of the heated iron, diftinét vifion was nearly reftored. Thefe four experiments fhow, that a change in the tempera- ture of mirrors, occafioned by heat, is attended with an altera- tion of their focal Jength ; and alfo prove, that the figure of the reflecting furface is confiderably injured, during the time that fuch a change takes place. We areconfequently authorifed to believe, that the {mall alteration in the focus of a mirror ex- pofed to the rays of the fun, arifes from the fame caufe. For, fince a thermometer, when the fun is fhining upon it, will fhow that its temperature is altered, the adtion of the folar rays upon a mirror muft be attended with a fimilar effe& in its tempera- ture. See obfervation 47, 48, 49, and 50. The fame experiments will now alfo explain why the obfer- vations of the fun, related in oar tranfit of Mercury, between 10" 32’ and 11" 28’, were not attended with fuccefs; for we have feen that heat occafions a derangement in the aétion of the reflecting furface ; and it follows that, under fuch circum- flances, high magnifying powers cannot be expected to fhow objects very diftinéily. If it thould be remarked, that I have not explained why the focus of a glafs mirror fhould fhorten by the fame rays of the fun which lengthen that of a metalline fpeculum, I confefs that _ - this at prefent does not appear; and, as it is not material to our purpofe, I might pafs it over in filence. We are however 2 pretty ! oy TRANSIT OF MERCURY, 9} pretty well affured, that the alterations of the focal length muft Experiments on - be owing to a dilatation of the glafs or metal of which mirrors pa od gth in are made, and muft be greateft where moft heat is applied. mirrors by heats Our experiments therefore cannot agree perfeétly with folar oblervations ; for, in the glafs mirror, the application of partial heat in front, muft undoubtedly have been much ftronger about _the middle of the mirror (though the centre of it was fome- times guarded by a brafs plate equal to the fize of the {mall fpeculum) than at the circumference. But when, on the con- trary, a mirror is expofed to the fun, every part of the furface will receive an equal portion of heat. It may alfo be faid, that I have pointed out a defeét in tele. fcopes ufed for folar obfervations, without afligning a cure for it. It will however be allowed, that tracing an evil to its caufe muft be the firft ftep towards a remedy. Had the imperfec- tion of the figure brought on by the heat of the folar rays been of a regular nature, an elliptical fpeculum might have been ufed to countera€&t the affumed hyperbolical form; or vice verfa. i And now, as, properly fpeaking, the derangement of the figure of a mirror ufed in obferving the fun, is not fo much caufed by the heat of its rays as by their partial application to the refleGting furface only, which produces a greater dilatation in front than at the back, there may be a poffibility of counter- aéting this effeét, by a contrary application of heat againft the back, or by an interception of it on the front, But this we leave to future experiments. Ill. Obfervations on the Chemical Nature of the Humours of the Eye. By Ricuarp Cuenevix, Lg. FR. S. and M. kt. I. A.* ‘Tue funétions of the eye, fo far as they are phyfical, have been fuund fubjeét to the common laws of optics. It cannot be expected that-chemiftry fhould clear up fuch obfcure points of phytiology, as all the operations of vifion appear to be ; but, fome acquaintance with the intimate nature of the fubftances * From the Philofophical Tranfactions, 1803. which 92 3h NATURE OF THE HUMOURS ON THE EYE. which produce the effects, cannot fail to be a ufeful appendage toa knowledge of the mechanical ftru€ture of the organ. Humours of the The chemical hiftory of the humours of the eye, is not of eye little known much extent. The aqueous humour had been examined by chemically. : i if : 5 Aqueous Bertrandi; who faid, that its fpecific gravity was 975, and humours therefore lefs than that of diftilled water. Fourcroy, in his Syftéme des Connoissances chimiques, tells us, that it has a faltifh . tafte ; that it evaporates without leaving a refiduum ; but chat -it contains fome animal matter, with fome alkaline phofphate and muriate... Thefe contradi@ions only prove, that we have no accurate knowledge upon the fubjeé. Vitreous The vitreous humour is not better known. Wintringham es has given its fpecific gravity (taking water at 10000) as equal to 10024; but I am not acquainted with any experiments to inveftigate its chemical nature. Cryftalline lens. We are told by Chrouet, that the cryftalline lens affords, by deftruétive diftillation, fetid oil, carbonate of ammonia, and water, leaving fome carbon in the retort. But, deftru@tive dif- tillation, although it has given us much knowledge as to animal matter in general, is too vague a method for inveftigating par- ticular animal fubftances. { thall now proceed to mention the experiments I have made upon all the humours. I fhall firft relate thofe which were made upon the eyes of fheep, (they being the moft eafily procured,) and fhall afterwards fpeak of thofe of the human body, and other eyes. I think it right to obferve, that all thefe eyes were © as frefh as they could be obtained. SHEEPS’ EYES. Aqueous Humour. Of theeps’ eyes; The aqueous humour is a clear tranfparent liquid, of the The aqueous f{pecific gravity of 10090 *, at 60° of Fahrenheit. When frefh, humour. Water, . A. albumen, gela- it has very little {mell, or tafte. tine and muriate It caufes very little change in the vegetable reactive colours ; of foda. and this little would not, I believe, be produced immediately after death. I imagine it to be owing to a generation of am- monia, fome traces of which I difcovered, * All thefe fpecific gravities are mean proportionals of feveral experiments. The eyes of the fame fpecies of animal, donot differ much in the Specific gravity of their humours, When NATURE OF THE HUMOURS OF THE EYE, 23 When expofed to the air, at a moderate temperature, it evaporates flowly, and becomes flightly putrid. When made to boil, a coagulum is formed, but fo fmall as _hardly to be perceptible. Evaporated to drynefs, a refiduum remains, weighing not more than 8 per cent. of the original liquor. Tannin caufes a precipitate in the frefh aqueous humour, both before and after it has been boiled, and confequently fhows the prefence of gelatine. Nitrate of filver caufes a precipitate, which is muriate of filver. No metallic falts, except thofe of filver, alter the aqucous humour. From thefe and other experiments it appears, that theaqueous humour is compofed of water, albumen, gelatine, anda muriate, the bafis of which I found to be foda. [have omitted {peaking of the aétion of the acids, of the alkalis, of alcohol, and of other re-agents, upon this humour. It is fuch as may be expeéted in a folution of albumen, of gelatine, and of muriate of foda, Cryftalline Humour. To follow the order of their fituation, the next of the humours Cry ftalline ‘is the cryftalline. os Much . i . reer proportion This differs very materially from the others. of albumen and Its fpecific gravity is 11000. gelatine. When frefh, it is neither acid noralkaline. It putrifies very rapidly. It is nearly all foluble in cold water, but is partly _ coagulated by heat. Tannin gives a very abundant precipitate ; but I could not perceive any traces of muriatic acid, when I had obtained the cryftalline quite free from the other humours. It is compofed, therefore, of a f{maller proportion of water than the others, but of a much larger proportion of albumen and gelatine. Vitreous Humour. I preffed the vitreous humour through a rag, in order to free Vitreous it from its capfules ; and, in that ftate, by_all the experiments )umeure, The I could make upon it, I could not perceive any difference aqueous. between it and the aqueous humour, either in its {pecific gravity, (which I have found to be 10090, like that of the other), or in its chemical nature, M. Fourcroy \ " Od, NATURE OF THE HUMOURS OF THE EYE. No phofphatein MM. Fourcroy mentions a phofphate, as contained in thefe thefe humours+ humours ; but I could not perceive any precipitation by muriate or nitrate of lime; nor did. the alkalis denote the prefence of any earth, notwithftanding M. Fourcroy’s affertion of that ~ fe HUMAN EYE. Human eye ; I could not procure a fufficient quantity of thefe, frefh enough not chemically t Itin] \ : a" | ies Iyantth different from 0 Multiply my experiments upon them. owever, by the other eyes. affiftance of Mr. Carpue, Surgeon to his Majefty’s Forces, I fully convinced myfelf, that the humours of the human eye, chemically confidered, did not contain any thing different from the refpe€tive humours of the eyes I had examined. ‘The aqueous and vitreous humours contained water, albumen, gela- tine, and muriate of {oda ; and the cryftalline humour contained only water, albumen, and gelatine. The fpecifie gravity of ; ihe aqueous and vitreous humours, I found to be 10053; while that of the cryftalline was 10790. EYES OF OXEN. So likewife the I found the eyes of oxen to contain the fame fubftances as eyes of oxen. the refpeGtive humours of other eyes. The fpecific gravity of the aqueous and viireous humours is 10088; and that of the cryftalline 10765. ; ‘ Probable law ; What is particularly worthy of notice is, that the difference that the {mailer : 3 z ” Pee oye the eaote which appears to exift between the fpecific gravity of the does the denfity aqueous or vitreous humour and that of the cryftalline, is much er a greater in the human eye than in that of fheep, and lefs in the ofthe other eye ef the ox. Hence it would appear, that the difference humours. between the denfity of the aqueous and vitreous humour and that of the cryftalline, is in the inverfe ratio of the diameter of the eye, taken from the cornea to the optic nerve, Should further experiments fhow this to be a univerfal law in nature, it will not be poffible to deny that it is in fome degree defigned for the purpofe of promoting diftinét vifion, pare In taking the {pecific gravity of the aqueous and vitreous euore delat - humours, no particular precaution is neceflary, except that they _ approaching the ought to be as frefh as poffible. But the cryftalline humour is os not of an uniform denfity throughout; it is therefore effential, that attention be given to preferve that humour entire for this. operation, I found the weight of a very’frefh cryftalline of an Ox , NATURE OF THE HUMOURS OF THE EYE. 25 ex to be 30.grains; ‘and its fpecific gravity was, as I before flated, 10765.. I then pared away all the external part, in every direétion, till there remained but fix grains of the centre, and the fpecific gravity of ihefe fix grains, I found to be 11940. From this it would feem, that the denfity increafes gradually, from the circumference to the centre. ~ It is not furprifing that the cryftalline humour fhould be Itis very fubjeé fubjeé to diforders, it being wholly compofed of animal matter ree of the moft perifhable kind. Fourcroy fays, that it is fome- lable nature. times found offeous in advanced age. Albumen is coagulated by many methods ; and, if we fuppofe that the fame changes can take place in the living eye as in the dead animal matter of the chemifts, it will be eafy to account for the formation of the cataraét; a diforder which cannot be cured but by the removal of the opaque lens. If a fufficient number of obfervas tions were made refpeting the frequency of the cataraé in gouty habits, fome important conclufions might be drawn, as to the influence of phofphoric acid, in caufing the diforder, by the common effect of acids, in coagulating albumen. IV. A Letter from Mr. Irvine concerning the late Dr. Invine, of Glafgow, his Doétrine, which afcribes the Difappearance of Heat, without Increafe of Temperature, to a change of Capacity _ in Bodies, end that of Dr. Buack, which fuppojes Caloric to become latent by Chemical Combination with Bodies ; with par- ticular Remarks on the Miftakes of Dr. THomeson, in his ° Accounts of thefe DoGrines. To Mr. NICHOLSON, SIR, In the article Chemiftry in the Supplement to the Encyclo- Account given pedia Britannica, in moft refpeéts excellently written, I could? the Encycls : ‘ : Britt. of the not fail to be ftruck with the account there given of the theory jnveftigation of. of heat, and the mode of inveftigating the natural zero adopted the zero of heats by the late Dr. Irvine. Had Dr. Thompfon been indifputably accurate in /és opinions, had a mathematically clofe argument left no door for the entrance of doubt, he would fcarcely even then 26 DR. IRVINE’S AND DR. BLACK’S then have been juftified in the terms he has ufed. But here we have every thing fettled, and we are informed with the air of an ancient fophift, that it is examined and found infuf- ficient. I am induced to make an,obfervation or two on this examination, becaufe I am informed that the mathematical air which reigns through this part of this work has actually im- pofed on many. For this time, however, I believe it can be fhewn that it is no more than an air, and that this fubje@ is not yet finally fettled. Dr. Thompfon’s. Dr. Thompfon fays, at page 269, Suppl. Ency, Brit. “ Dr. 2 Sania Irvine, of Glafgow, advanced a theory on this fubjec dif- r. Irvine’s theory of heat. ferent from that of Dr. Black. The fpecific caloric of water That caloric —_ being greater than that of ice, it requires a greater quantity of abforbed by ice pes Hee : : : on its converfion Caloric to raife it to a given temperature than it does to raife into iyi ice. The caloric therefore does not become latent, it only aegis Soman feems to do fo from the greater fpecific caloric of water. This rature) only theory was zealoufly adopted by Dr. Crawford. | Dr. Black seca obferved very juftly, that it did not account for the produétion really employed Of fluidity at all. The fpecific caloric of water is indeed in keeping up the greater than that of ice; but how is the ice converted into temperature while the capa- Water? This is an objeGtion which the advocates for Dr. eity is increafed; Iryine’s or Dr. Crawford’s theory, (as it has been improperly eee called) will not catty antwen' oLet ine whether thi doesitetexplain Calle ) will not eafily anfwer. Let us examine whether this , the aét of theory accounts for the apparent lofs of caloric. It follows - ae from Mr. Kirwan’s experiments, that the fpecific caloric of Dr. Thompfon. water is to that of ice as 10 to9. Dr. Black proved, that as The capacity of much caloric entered the ice as would have raifed it had it been is to tha : I of ice “ ey water, 140°. Let us fuppofe that it would only have raifed —Iceduring the ice 140; in that cafe the melted ice ought to have been of fufion abforbs oo 7 ; what would have the temperature of 158°, for 10:9::140: 126, but it was raifed water only 32°, Therefore 126° of caloric have difappeared, and | paar \ ° , “ce . Bee ges eee cannot be accounted for by the change of fpecific caloric. raiféd the ice at Nor can the accuracy. of Dr. Black’s experiment be fulpeéted ; Jeaft as much if if has been repeated in every part of the world, and varied 3t had remained . folid—whence in every poflible way. We cannot doubt, therefore, that itis inferred caloric unites with fubflances, and caufes them to become hat the fufed : sec : Nia, ante : ide hee fluid, or that there is in fact a caloric of fluidity different from eught tohave {pec fic caloric.” ie Now nobody doubts Dr. Black’s experiment, and it is not 326%, ifthe neceflary to our argument to have any doubt on that fubjeét. difference of : ; BN oN : a9 panty hid Dr. Thompfon gives it as a fair {tatement of Dr. Irvine’s thes alone operated ory, in the cafe; THEORIES OF HEAT. ye ery, that the 1403 entering ice during its change of forms, But it escatt fhould be leffened in the ratio of 9: 10, and fhould therefore ea rea be 126°, or in other words, if the heat entering the ice were the 126° of only-enough to raife the ice 140°, that the temperature of the heat are con= ° ae beef fidered as having water fhould be 158°. But it is eafy to fee that on this fup- beyond doubt pofition the water would contain two portions ofheat, namely, ps5 By * ages c t an its original quantity from the natural zero to 32°, expreffed 5.57 in degrees according to the capacity of ice, and the fuperadded Reply. Dr. 4 : ‘ that Thompfon in his portion from 32 to 158, expreffed in degrees according tO ne cm ent CPA of water. The ice would no doubt according to this ftatement, change of capa- become water without abforbing any heat, and the water “ty, attends to i S the fuperadded would be merely heated as in every other cafe. But Dr. Ir- je. only, and vine, and after him Dr. Crawford, and the writers of ele- noah eet; . t t mentary treatifes for the laft fifteen years, and I believe I may esting apt a venture to fay every one of our philofophers, except Dr. Thomp- body. fon himfelf, have ftated this doétrine of capacities to be, that no ha every one of the thermometrical degrees expreffing the whole We. Mien of the heat contained in a body, are to be taken in proportion is nynitere but c i ; 5 : re ‘Vhompfon to its capacity ; and therefore that if the ice fuddenly changed rth, eer its capacity, it would abforb not merely a rateable proportion the qwéole eat of what heat might be prefented to it, but an abfolute quan. i 4 bedy ata . ‘ s given temp€rae tity to make up for its new capacity. For the heat neceffary ture as the mea- to raife the temperature of ice each degree from natural zero, /ure of its capa~ . dis . tye is to the heat neceflary to raife water each degree from the 4G fame point as the capacity of the one body is to that of the other. Ice cannot then as it acquires its new form, thew any Ice in fufion augmentation of temperature till the differences between the 74/45 all the F _ beat prefented te heats of each degree from the loweft point be made up. Thisic until its ene difference amounts to the 140° found by the experiment, and pan rime . Keates rp 3 ished, an cannot raife the water even the fraction of a degree in tempe- cannot till then rature, becaufe it is barely fufficient for the demands of Big Pavan aac new capacity. Had the 140° been applied to water, Dr. ‘“™Peratures Thompfon’s affertion of the rife of temperature would have been juft, but it can have no reference whatever to heat ap- plied during a change of capacity. The fame arguments are repeated in page 271, and the fame If the capacity miftake reigns through the whole. Is it not obvious, that te eee . : . . . uddeni - you would inftantaneoufly increafe the capacity of any body, creafed iatees it would immediately become colder, and its temperature fink perature would as much lower as its new capacity was higher. In the fame ‘13 or it would cone way, if a body has its capacity fuddenly increafed, and at the tinue ftationary ame if due heat were fam added 5 and this ts the cafe with ice. hence, &c, as before. The caufe of fluidity afcribed to the fame ation of heat which enlarges the capacities of bodies. ‘The experi- ments on heat ace moftly too Inaccurate to give the fame depreffion for the uatural zero, DR. IRVINE’S AND DR: BLACK’S fame time a quantity of heat added to it to make the whole heat in proportion to its new capacity, furely that body would continue exaétly at the fame thermometrical point. Now melting ice is that body; the 140° are demanded by new capa- city,—would have been more if its capacity had been greater, and lefs if lefs. On the very principles therefore in difpute, ice on becoming water ought to receive a quantity of heat, and that quantity isnot governed by the proportion of 9 to 10, but the whole heats are in that proportion, and the 140° is only their difference. Fer all calculations on tke alteration of temperature to be produced by a given portion of heat on a body, from the knowledge of the relation of its capacity to another, and of the number of degrees that other is railed by the fame quantity, continue juft only while the capacities con- tinue in the fame proportion. Surely it is poffible to form a notion that heat (140°,) may enter into water as the very caufe of fufion, fo ds to alter its ftate and change its capacity ; that very heat making the quan- tum due to the new capacity. It is the faét, that ice at 32° cannot bear the fmalleft addition of heat in that ftate, but im- mediately begins to be converted into water. Leta quantity much lef{s than reprefented by 140°, enter a given portion of ice, fay 4 a degree. A fmall portion of the ice becomes water ; its capacity being increafed as 9:10, and here the procefs flops; the entire mafs of ice and water remaining at 32°. More heat would alter the ftate and enlarge the capa-- city of more of the ice, without raifing its temperature ; that is to fay, would fufe it. How this is done, or in other words, what it is that happens among the particles may not be eafy to explain or to imagine; but in my apprehenfion this hypo- thetical part of the difcuffion would be at leaft as obfcure in the do@rine of latent or combined heat, as in that which afcribes the difappearance of heat during fufions to the enlargement of capacity. As to the difagreement of refults in the hands of different philofaphers concerning the natural zero, it is to be obferved, that it is one thing to determine whether bodies have different capacities for heat, and: another to exprefs thefe by accurate numbers. There can be no doubt of the fact that bodies have different capacities, and Dr. Irvine’s theorem may enuntiate itfelf generally, by faying, that as the capacity of the folid is to THEORIES OF HEAT. 929 to that of the fluid, fo is the whole heat of the folid to that of the fluid. But it is a widely different thing to determine pre- cifely the capacities of airs, and various other fubftances, ex- , periments on which are fubje& to great inaccuracy, and muft be carefully repeated many times before a philofopher fhould pretend to draw final, and ftill lefs elementary, conclufions. Many of the experiments by which contradiétory refults have been obtained were made, (as I am told, for I have not yet had an opportunity of examining mylelf) by the calorimeter, an inftrument liable to great and deferved objeétions. Lavoifier, by mixing fulphuric acid and water made the natural zero 5803: my father by a fimilar procefs fomewhere I think be- tween 8 and 900. What will Dr. Thompfon make of this ? Surely he will not conclude the theorem falfe, but one expe- menter wrong ; moft likely both inaccurate. It is very ftrange indeed that Dr. Thompfon fhould have Dr. Thompfon found it dificult to underftand how thefe 140° enter ice during Fie fufion without raifing its temperature. All he fays amounts of ice eae aly to this, that a given quantity of heat will have more effect in changed ducing ; ; . theexperiment. raifing the temperature of ice than that of water. But the ice muft continue ice, and the water water, and a change of ca- pacity alters the whole reafoning. Before he can tell whether 140 fhould be 14 or not, he muft tell me the whole heat of ice, _and let me examine whether that be to itfelf plus, 140 as 9: 10 -ornot. He is exaétly in the fame error with regard to fteam. Deidisaees As to a mode of finding the capacities of ice and water, Of method of afcer- ¢ which my father was the undoubted difcoverer, as well as of taining the capa- the general faét that all bodies change their capacity and form LENO tn together, one of Irvine’s modes was this: he mixed fine river afcertaining how fand wafhed, or fine pounded glafs of a given temperature i oe with each, fo as to raife or reduce each an equal number of equal change of degrees, Then the capacities: were as the quantities of glafs pa ipa si added to produce the fame effect. Dr. Thompfon fays, that there is no proof that the capaci- aed ais ties of bodies are as their abfolute heats. The capacity of iron, capacities are not he continues, is greater than that of water or even that of azotic igs Piel as gas, yet it is improbable that iron contains more heat than heats. _ thefe fubftances. Now where did Dr. Thompfon find that Inftance of irons .the capacity of iron was greater than that of water and azotic ee gas? not in his own table furely. There iron by weight has and contain lets capacity 0.1264, water 1,000, azotic gas, 0.7036, or as Dr. sete Crawford miftakenly. 40 THEORIES OF HEAT. Crawford fays, .7936. Even of equal bulks that of iron is . lefs than that of water, as I fee in the fame table. I can only fuppofe that Dr. Thompfon has ftumbled on the fpecific gravi- ties inftead of {pecific heats, and there he would have been right enough. The fame expe- IT will fay only a few words farther on the queftion, whether riment that de- ae : lags ; Ay aes penance Tackle bodies contain caloric in proportion to their fpecific heats or heats is alfo the not. Now firft of all when they continue of the fame capa- ile oe cities. Suppofe the capacity of a body to be to that of water abfoluteheats aS 10 to5,72.e. double. The fame quantity of heat that raifes s (4 dete water two degrees, raifes it one; 2° more raife the body one extende r the whole range More, and fo on as far as we can go upwards, and the reverfe from zero) = downwards in the fcale. But fuppofe another body whofe taken to be in See je mae ; the fame ratio. C@pacity is to that of water as 20 to 5, 7. e. quadruple. Each 4° of the heat in water raife this new body one degree up- wards, and the reverfe downwards, as faras we know. Now is it not probable here that the whole heats are in proportion io the capacities thus determined, fince like thermometrical portions of heat taken out of each and applied to water affeet it in that ratio? The fpecific heats of bodies are faid to be | different, when the fame quantity of heat raifes one a different number of degrees from the other, and that regularly as far as we can examine. ‘Therefore each degree in each contains a quantity of heat proportional to its capacity, But the whole heat is made up of degrees, therefore the whole heats are proportional if the capacities remain the fame. Dr. Thomp- fon grants this to be abfolute fa& to the extent of our experi- ments. ; If the capacities But if the capacity be fuppofed to vary, firft let it diminith. Peel vey Then the quantity of heat given out is the difference of the while the tempe= ; raturechanges, Whole heats of the two different ftates of the body; and the the only confe- whole-heat of it in each ftate is proportional to its capacity, quence would be, : : ee that beat would and the whole heat of its higheft capacity is equal to that of be given out or its loweft plus the heat given out. Therefore the change of abferbed ll 1 capacity has made no alteration on the whole heat of the body common tempera- capacity has made no alteration on the whole heat of the body ture werersftored; computed from a higher point, but will turn out the fame as su peneoe if no change had taken place. ] awould be propor- If the capacity be fuppofed to increafe, a fimilar reafoning a. mW would fhew that the heat ftill may be computed in the fame 7 way. Such are a few arguments on the other fide of the quef- tion EXPERIMENTS ON ASTRINGENT VEGETABLES. Q1 tion from Dr. Thompfon, by no means all that might be brought, nor dare I venture to hope fo ftated as to be beyond the reach of cenfure. Many more curious points rife before the imagination on fo Oacaae ee interefting a fubjeét as heat. As I hope, however, foon tobe eaitnie at ae able to lay before the public fome of my father’s writings, I late Dr. Irvine, may on that occafion have an opportunity of exprefling my felf at greater length than I can intrude in your journal. lam, SIR, Your obedient humble fervant, ghia WILLIAM IRVINE. Bedford-Street, Covent-Garden. awh An Account of fome Experiments and Obfervations on the Confti- tuent Parts of certain Aftringent Vegetables ; and on their Ope- ration in Tanning. By Humepury Davy, Efq. Profe/~ for of Chemiftry in the Royal Inftitution. - (Concluded from Page 256, Vol. V.) LV. EXPERIMENTS AND OBSZRVATIONS ON THE AS- TRINGENT INFUSIONS OF BARKS, AND OTHER VEGE-= TABLE PRODUCTIONS. Vue barks that I examined were furnifhed me by my friend Infufions of ‘Samuel Purkis, Efq. of Brentford; they had been colleéted in Parks in water ; y gentle heat. the proper feafon, and preferved with care. In making the infufions, I employed the barks in coarfe powder ; and, to expedite the folution, aheat of from 100 to 120° Fahrenheit was applied. The ftrongeft infufions of the barks of the oak, of the Lei- Of oak, willow, cefter willow, and of the Spanifh chefnut, were nearly of the ven fame {pecific gravity, 1.05. Their taftes were alike, and ftrong- ; ly aftringeut; they all reddened litmus-paper ; the infufion of the Spanifh chefnut bark producing the higheft tint ; and that of the Leicefter willow bark the feebleft tint. Two hundred grains of each of the infufions were fubmitted were chemical- to evaporation; and, in this procefs, the infufion of the oak 'Y **#™ined- bark \ 32 Chemical ex- amination of various barks. EXPERIMENTS GN ASTRINGENT VEGETABLES. bark furnifhed 17 grains of folid matter; that of the Leicefter willow about 162 grains ; and that of the Spanifh chefnut nearly an equal quantity. The tannin given by thefe folid matters was, in that from the oak bark infufion, 14 grains; in that from the willow bark in- fufion 142 grains; and in that from the Spanifh chefnut bark infufion 13 grains. The refidual {ubftances of the infufions of the Spanifh chel- nut bark, and of the oak bark, flightly reddened litmus-paper, and precipitated the folutions of tin of a fawn colour, and thofe of iron black. The refidual matter of the infufion of the wil- low bark, did not perceptibly change the colour of litmus ; but it precipitated the falts of iron of an olive colour, and render- ed turbid the folution of nitrate of alumine. The folid matters produced by the evaporation of the infu- fions, gave, by incineration, only a very fmall quantity of afhes, which could not have been more than ,2, of their ori- ginal weights. Thefe afhes chiefly confifted of calcareous earth and alkali; and the quantity was grealeft from the infu- fion of chefnut bark. The infufions were aéted on by the acids, and the pure alkalis, ina manner very fimilar to the infufion of galls. With the fo- lutions of carbonated alkalis, they gave denfe fawn-coloured precipitates. They were copioufly precipitated by the folutions of lime, of ftrontia, and of barytes; and, by lime-water. in excefs, the infufions of oak and of chefnut bark feemed to be deprived of the whole of the vegetable matter they held in - folution. By being boiled for fome time with alumine, lime, and mag- nefia, they became almoft colourlefs, and loft their power, of © acting upon gelatine and the falts of iron. After being heated with carbonate of lime and carbonate of magnefia, they, were found deeper coloured than before; and, though they had loft their power of aéting on gelatine, they ftill gave denfe olive- . coloured precipitates with the falts of iron. In all thefe cafes, the earths gained tints of brown, more or le(s intenfe, When the compound of the aftringent coinealead of the in- fufion of oak bark with lime, procured by means of lime-water, was acted on by fulphuric acid, a folution was obtained, which pre- EXPERIMENTS ON ASTRINGENT VEGETABLES. 33 precipitated gelatine, and contained a portion of the vegetable principles, and a certain quantity of fulphate of lime; a folid fawn-coloured matter was likewife formed, which appeared to be fulphate of lime, united to alittle tannin and extraétive matter. * aa were copioufly precipitated by folution of al- aM men. The precipitates they gave with gelatine were fimilar in their appearance ; their colour, at firft, was a light tinge of brown, but they became very dark by expofure to the air. Their com- pofition was very nearly fimilar; and, judging from the ex- periments on the quantity of gelatine employed in forming them, the compound of tannin and gelatine from the ftrongeft infufion of oak bark, feems to confift, in the 100 parts, of 59 parts of gelatine and 41 of tannin; that from the infufion of Leicefter willow bark, of 57 parts of gelatine and 43 of tannin ; and that from the infufion of Spanifh chefnut bark, of 61 parts of gela- tine and 39 of tannin, Two pieces of calf-fkin, which weighed when dry 120 grains Experiments of each, were tanned ; one in the ftrongeft infufion of Leicefter ee re willow bark, and the other in the ftrongeft infufion of oak bark. fions of barks. The procefs was completed, in both inftances, in lefs than a , fortnight ; when the weight of the Jeather formed by the tannin of the Leicefter willow bark was found equal to 161 grains; and that of the leather formed by the infufion of oak bark was equal to 164 grains. When pieces of fkin were fuffered to remain in fmall quan- Spent ouze or tities of the infufions of the oak bark, and of the Leicefter wil. infusion. low bark, till they were exhaufted of their tanning principle, it was found, that though the refidual liquors gave olive-colour- ed precipitates with the folutions of fulphate of iron, yet they were fcarcely rendered turbid by folutions of muriate of tin; and there is every reafon to fuppofe, that a portion of their ex- tra€tive matter had been taken up with the tannin by the fkin, * M. Merat Guillot propofes a method of procuring pure tannin, (Annales de Chimie, Tome XLi. p. 325.) which confifts in pre- cipitating a folution of tan by lime-water, and decompofing it by nitric or muriatic acid. The folution of the folid matter, obtained in this way in alcohcl, he confiders as a folution of pure tannin; but, from the experiments above-mentioned, itappears, that it muft contain, befides tannin, fome of the extragtive matter of the bark; and it may likewife contain faline matter. Vou, VI.—SepremBer. D I at- 84 EXPERIMENTS ON ASTRINGENT VEGETABLES. I attempted, in different modes, to obtain uncombined galli¢ acid from the folid matter produced by the evaporation of the barks, but without fuccefs. When portions of this folid matter were expofed to the degree of heat that is required for the pro- duétion of gallic acid from Aleppo galls, no cry ftals were form- ed; and the fluid that came over gave only a brown colour to the folution of falts of iron, and was found to contain much acetous acid and empyreumatic oil. When pure water was made to aét, in fucceflive portions, upon oak bark in coarfe powder, till all its foluble parts were taken up, the quantities of liquor laft obtained, though they did not act much upon folution of gelatine, or perceptibly red~ den litmus-paper, produced a denfe black with the folution of fulphate of iron: by evaporation, they furnifhed a brown mat- ter, of which a part was rendered infoluble in water by the action of the atmnofphere; and the part foluble in water was not in any degree taken up by fulphuric ether; fo that, if it contained gallic acid, it was ina ftate of intimate union with extractive matter. low tanning Two pieces of calf-fkin, which weighed when dry 94 grains sesh fun each, were flowly tanned 5 one by being expofed to a weak in- of the leather fufion of the Leicefter willow bark, and the other by being acted than quick, and ynon by a weak infufion of oak bark. The procefs was com- more of the mu- : : ; : cilage is taken Pleted inabout three months; and it was found, that one piece De of {kin had gained in weight 14 grains, and the other piece about 162 grains. This increafe is proportionally much lefs : - than that which took place in the experiment on the procefs of quick tanning. The colour of the pieces of leather was deeper than that of the pieces which had been quickly tanned; and, to judge from the properties of the refidual liquors, more of the extraétive matters of the barks had been combined with them. The experiments of Mr. Biggin * have fhown, that fimilar barks, when taken from trees at different feafons, differ as to the quantities of tannin they contain: and I have obferved, ihat the proportions of the aftringent principles in barks, vary confiderably according as their age and fize are different ; be- fides, thefe proportions are often influenced by accidental cir- cumftances, fo that it is extremely difficult to afcertain their diftin€ relations to each other. *-Phil, Tranf. for 1799, page 299, In FXPERIMENTS ON ASTRINGENT VEGETABLES. 35 Tn every aftringent bark, the interior white bark (that is, the HR part next to the ibarnten’ contains the largeft quantity of tan- mo tannin ; nin. The proportion of extraétive matter is generally greateft the middle moft s : ; ? extractive ; and in the middle or coloured part: but the epidermis feldom fur- 44. épidermis nifhes either tannin or extraétive matter. little of eithers The white cortical layers are comparatively moft abundant in Young trees young trees ; and hence their barks contain, in the fame weight, Be a larger proportion of tannin than the barks of old trees. In barks of the fame kind, but of different ages, which have been cut at the fame feafon, the fimilar parts contain always very nearly the fame quantities of aftringent principles; and the in- terior layers afford about equal portions of tannin, An ounce of the white cortical layers of old oak bark, fur- are quanti- nifhed, by lixiviation and fubfequent evaporation, 108 grains of “* folid matter ; and, of this, 72 grains were tannin. An equal quantity of the white cortical layers of young oak produced 111 grains of folid matter, of which 77 were precipitated by gela- tine, An ounce of the interior part of the bark of the Spanith chefnut, gave 89 grains of folid matter, containing 63 grains of tannin. The fame quantity of the fame part of the bark of the Lei- eefter willow, produced 117 grains, of which 79 were tannin. An ounce of the coloured or external cortical layers from the oak, produced 43: grains of folid matter, of which 19 were tannin. From the Spanifh chefnut, 41 grains, of which 14 were tannin. And, from the Leicefter willow, 34 grains, of which 16 were tannin. In attempting to afcertain the relative quantities of tannin in the different entire barks, I fele&ted thofe fpecimens which ap- peared fimilar with regard to the proportions of the external and internal layers, and which were about the average thick- nefs of the barks commonly ufed in tanning, namely, half an inch, Of thefe barks, the oak produced, in the quantity of an ounce, 61 grains of matter diffolved by water, of which 29 _ grains were tannin. The Spanith chefnut 53 grains, of which 21 were tannin, And the Leicetter willow 71 grains, of which 33 were tan- nin. D2 The Properties of the refijual portion of infufed barks. Elm and willow bark, infufions of fumachs from Sicily and Ma- laga. EXPERIMENTS ON ASTRINGENT VEGETABLES. The proportions of thefe quantities, in refpeét to the tanning principle, are not -very different from thofe eftimated in Mr. Biggin’s table.* The refidual fubftances obtained in the different experiments, differed confiderably in their properties; but certain portions of them were, in all inftances, rendered infoluble during the pro- cefs of evaporation. The refiduum of the chefnut bark, as in the inftance of the ftrongeft infufion, poffefled flightly acid properties ; but more than 2 of its weight confifted of extrac- tive matter. All the refiduums in folution, as in the other cafes, were precipitated by muriate of tin; and, after this pre- cipitation, the clear fluids a€ted much more feebly than before on the falts of iron; fo that there is great reafon for believing, that the power of aftringent infafions to precipitate the falts of _ iron black, or dark coloured, depends partly upon the agency of the extractive matters they contain, as well as upon that of the tanning principle and gallic acid. In purfuing the experiments upon the different aftringent infufions, I examined the infufions of the bark of the elm and of the common willow. Thefe infufions were aéted on by re- agents, in a manner exaétly fimilar to the infufions of the other barks: they were precipitated by the acids, by folutions of the alkaline earths, and of the carbonated alkalis; and they form- ed, with the canftic alkalis, fluids not precipitable by gelatine. An ounce of the bark of the elm, furnifhed 13 grains of tannin, The fame quantity of the bark of the common willow, gave 11 grains. The refidual matter of the bark of the elm, contained a con- fiderable portion of mucilage; and that of the bark of the willow, a fmall quantity of bitter principle. The ftrongeft infufions of the fumachs from Sicily and Ma- laga, agree with the infufions of barks, in moft of their pro- perties; but they differ from all the other aftringent infufions that have been mentioned, in one refpect; they give denfe pre- cipitates with the cauftic alkalis. Mr. Prouft has fhown, that fu- mach contains abundance of fulphate of lime; and it is. pro- bab!y to this fubftance that the peculiar effect is owing. From an ounce of Sicilian fumach, I obtained 165 grains of matter foluble in water, and, of this matter, 78 grains were fannin, * Philofophical Tranfaétions for 1799, p. 263. i An #XPERIMENTS ON ASTRINGENT VEGETABLES. 39 An ounce of Malaga fumach, produced 156 grains of folu- ble matter, of ial 79 appeared to be tannin. The infufion of Myrobalans * from the Eait Indies, differed Of Myrobalanse from the other aftringent infufions chiefly by this circumftance, thatiit effervefced vith the carbonated alkalis ; and it gave with them a denfe precipitate, that was almoft immediately redif- folved. After the tannin had been precipitated from it by ge- latine, it ftrongly reddened litmus-paper, and gave a bright black with the folutions of iron. I expeéted to be able to pro- cure gallic acid, by diftillation from the Myrobalans; but in this I was miftaken ; they furnifhed only a pale yellow fluid, which gave merely a flight olive tinge to folution of fulphate of iron. Skin was fpeedily tanned in ihe infufion of the Myrobalans ; and the appearance of the Jeather was fimilar to the appear- ance of that from galls. The ftrongeft infufions of the teas are very fimilar, in their agencies upon chemical tefts, to the infufions of catechu. An ounce of Souchong tea, produced 48 grains of tannin. The fame quantity of green tea, gave 41 grains. Dr. Maton has obferved, that very little tannin is found in cinchona, or in the other barks fuppofed to be poffeffed of febrifuge properties. My experiments tend to confirm the ob- fervation. None of the infufions of the ftrongly bitter vegetable fubftances that I have examined, give any precipitate to gela- tine, And the infufions of quaffia, of gentian, of hops, and of chamomile, are {carcely affe€ted by muriate of tin; fo that they likewife contain very little extraétive matter. In all fubftances poffefled of the aftringent tafte, there is great reafon to fufpeét the prefence of tannin; it even exiftsin fubftances which contain fugar and vegetable acids. I have found it in abundance in the juice of floes; and my friend Mr, Poole, of Stowey, has detedted it in port wine. | V. GENERAL OBSERVATIONS, Mr. Prouft has fuppofed, in his paper upon tannin and its Probability that Species,+ that there exift different {pecies of the tanning prin- sy cries ciple, poffeffed of different properties, and different pas tanning mattere * The Myrobalans ufed in thefe experiments are the fruit of the Terminalia Chebula. Retz. Obs. Botan. Fale, V. p. 31. ¢ Annales de Chimie, Tome XLI. p. 332. : re The fpecific agencies of tannin in all in= fufions are the fame. Its affinities and habitudes. EXPERIMENTS ON ASTRINGENT VEGETABLES. of aéting upon re-agents, but all precipitable by gelatine. This opinion is fufficiently conformable to the faéts generally known concerning the nature of the fubftances which are pro- duced in organifed matter; but it cannot be confidered as proved, till the tannin in different vegetables has been ex- amined in its pure or infulated ftate. In all the vegetable infufions which have been fubjeéted to experiment, it exits in a ftate of union with other principles; and its properties muft neceffarily be modified by the peculiar circumftances of its combination, From the experiments that have been detailed it appears, that the /pecific agencies of tannin in all the different aftringent infufions are the fame. In every inftance, it is capable of en- tering into union with the acids, alkalis, and earths; and of forming infoluble compounds with gelatine, and with fkin, The infufions of the barks affeét the greater number of re-agentsina manner fimilar to the infufion of galls; and, that this laft fluid is rendered green by the carbonated alkalis, evidently depends upon the large proportion of gallic acid it contains. The infu- fion of fumach owes its charateriftic property, of being pre- cipitated by the cauftic alkalis, to the prefence of fulphate of lime; and, that the folutions of catechu do not copionfly pre- cipilate the carbonated alkalis, appears to depend upon their containing tannin in a peculiar ftate of union with extradlive matter, and uncombined with gallic acid or earthy falts, In making fome experiments upon the affinities of the tanning principle, I found that allthe earths were capable of attraéting it from the alkalis: and, fo great is their tendency to combine with it, that, by means of them, the compound of tannin and gelatine may be decompofed without much difficulty ; for, after pure magnefia had been boiled for a few hours with this fubftance diffufed through water, it became of a red-brown colour, and the fluid obtained by filtration produced a diftin@ precipitate with folution of galls. The acids have lefs affinity for tannin than for gelatine ; and, in cafes where compounds of the acids and tannin are aGted on by folution of gelatine, an equilibrium of affinity is eftablifhed, in confequence of which, by far the greateft quantity of tannin is carried down in the in- foluble combination. The different neutral falts have, com. paratively, feeble powers of attraGtion for the tanning principle ; but, that the precipitation they occafion in aftringent folutions, is ~ EXPERIMENTS ON ASTRINGENT VEGETABLES. 89 is not fimply owing to the circumftance of their uniting to a portion of the water which held the vegetable fubftances in fo- lution, is evident from many faéts, befides thofe which have een already ftated. The folutions of alum, and of fome other falis which are lefs foluble in water than tannin, pro- duce, in many aftringent infufions, precipitates as copious as the more foluble faline matters ; and fulphate of lime, and other earthy neutral compounds, whichare, comparatively fpeaking, infoluble in water, {peedily deprive them of their tanning principle. From the different faéts that have been ftated, it is evident It is not always that tannin may exift in a ftate of combination in different fub- pl as ey ftances, in which its prefence cannot be made evident by means of folution of gelatine; and, in this cafe, to deteé its exiftence, it is neceflary to have recourfe to the a¢tion of the diluted acids. In confidering the relations of the different faéts that have Skins in tanning been detailed, to the proceffes of tanning and of leather-making, ae ae it will appear fufficiently evident, that when {kin is tanned in aftringent infufions that contain, as well as tannin, extractive matters, portions of thefe matters enter, with the tannin, into chemical combination with the fkin. In no cafe is there any reafon to believe that gallic acid is abforbed in this procefs 5 and M. Seguin’s ingenious theory of the agency of this fub- ftance, in producing the deoxigenation of {kin, feems fup- ported by no proofs. Even in the formation of glue from fkin, there is no evidence which ought to induce us to fuppofe that it lofes a portion of oxigen; and the effect appears to be owing merely to the feparation of the gelatine, from the fall quantity of albumen with which il was combined in the orgae nifed form, by the folvent powers of water. The different qualities of leather made with the fame kind os bee ale of fkin, feem to depend very much upon the different quantities affedied by it : of extractive matter it contains. The leather obtained by means of infufion of galls, is generally found harder, and more liable to crack, than the leather obtained from the infufions of barks ; and, in all cafes, it contains a much larger proportion of tannin, and a fmaller proportion of extraétive matter. | When fkin is very flowly tanned in weak folutions of the Soft durable barks, or of catechu, it combines with a confiderable proportion ae flow of extractive matter; and, in thefe cafes, though the increafe of r@) EXPERIMENTS ON ASTRINGENT VEGETABLES. of weight of the {kin is comparatively fmall, yet it is rendered perfectly infoluble in water ; and is found foft, and at the fame time ftrong. The fatarated aftringent infufions of barks contain much lefs extra€tive matter, in proportion to their tannin, than the weak infufions ; and; when {kin is quickly tanned in them, common experience fhows that it produces leather lefs durable than the leather flowly formed. The common Befides, in the cafe of quick tanning by means of infufions opinion in favour of barks, a quantity of vegetable extraétive matter is loft to the of what is called * : : f feeding of the Manufacturer, which might have been made to enter into the leather probably compofition of his leather. Thefe obfervations fhow, that there ant. is fome foundation for the vulgar opinion of workmen, con- cerning what is technically called the feeding of leather in the flow method of tanning ; and, though the proceffes of the art may in fome cafes be protraéted for an unneceffary length of time, yet, in general, they appear to have arrived, in con- fequence of repeated praétical experiments, at a degree of perfection which cannot be very far extended by means of any elucidations of theory that have as yet been made known. On the firft view it appears fingular that, in thofe cafes of tanning where extra@live matter forms a certain portion of the leather, the increafe of weight is lefs than when the {kin is combined with pure tannin ; but the faét is eafily accounted for, when we confider that the attraGtion of {kin for tannin muft be probably weakened by its union with extraétive matter; and, whether we fuppofe that the tannin and extraétive matter enter together into combination with the matter of fkin, or unite with feparate portions of it, flill, in either cafe, the primary attraGion of tannin for {kin muft be, toacertain extent, diminifhed Vegetables are In examining aftringent vegetables in relation to their powers Se A of tanning {kin, it is neceflary to take into account, not only by the matter the quantity they contain of the /ubfance precipitable by gela- that glue can tine, but likewife the quantity, and the nature, of the extraétive a aie matter; and, in cafes of comparifon, it is effential to employ infufions of the fame degree of concentration. Catechu is the It is evident, from the experiments detailed in the IIId fec- mot powerful tion, that of all the aftringent fubftances which have been as fanning material. ; : ; : yet examined, catechu is that which contains the largeft pro- portion of tainin; and, in fuppofing, according to the common eflimation, that from four to five pounds of common oak bark are METHOD OF RAISING WATER. A] are required to produce one pound of leather, it appears, from the various fynthetical experiments, thai about half a pound of catechu would anfwer the fame purpofe *. Alfo, allowing for the difference in the compofition of the Its comparative different kinds of leather, it appears, from the geneval detail of sa cae faéts, that one pound of catechu, for the common ufes of the tanner, would be nearly equal in value to 24 pounds of ies to 7; pounds of the bark of the Leicefter villi to 11 pounds of thie bark of the Spanifh’ chefnut, to 18 pounds of the bark of the elm, to 21 pounds of the bark of the common willow, and to 3 pounds of fumach. . Various men{truums have been propofed for the purpofe oe and other expediting and improving the procefs of tanning, and, amongft robs tines them, lime-water and the folutions of pearl-afh: but, as thefe ful. two tubftances form compounds with tannin which are not de- compofable by gelatine, it follows that their effects muft be highly pernicious; and there is very little reafon to fuppofe, that any bodies wili be found which, at the fame time that they increafe the folubility of tannin in water, will not likewile di- minifh its attra€tion for {kin. VI. An eafy Method of raifing Water for the Purpofes of Refrigeration én Dijirlleries, Steam Condenjers, &c. By Sir A. N. Epe- CRANTZ. Communicated by the Inventor. "Tue method exhibited in the fketch, Fig. II. Plate IV. Introductions being capable of faving near thirty feet of the height to which water may be required to be pumped, for the ufes mentioned in the title, appeared too fimple and ingenious, when the learn- ed inventor did me the honour to mention it in converlfation, for me not to require permiffion 1o communicate it to my readers. * This eftimation agrees very well with the experiments lately made by Mr. Purkis, upon the tanning powers of Bombay catechu in the proceffes of manufacture, and which he has permitted me to mention. Mr. Purkis found, by the refults of different accurate experiments, that one pound of catechu was equivalent to feven or eight of oak bark. 3 If 42 METHOD OF RAISING WATER. The principle of If the worm tube were open at the top as ufual, itis evident aero pe that all the water employed for cooling, would require to be acurrentof _raifed by fome mechanic force as high as the furface ; fuppofe mi os 4 twenty feet. But as this water is not wanted for ufe at that elevation, but is only required to give out its heat, and then fall down again; it is clear that this fall may be applied to raife a confiderable portion of what is’to follow. Various means might be devifed for fuch an application ; the fimpleft and moft effeétual, no doubt, is that to which Sir A. N. has given the preference, namely to convert the whole apparatus into a fyphon. Defcription of Suppofe the worm tub to be clofed at top; the cold water the apparatuss conveyed into it at the bottom from the veffel A, and carried off heated at top by the pipe B into the overflowing veffel C. Let us fuppofe the level in A to be two feet higher than that in C, and acurrent will be kept up through the whole fluid as long as may be defired. Whether the It muft occur to the experienced engineer that gas or air ea ett or Willefcape from the water, efpecially when heated and defended impede the from the preflure of the atmofphere. But this may be obviated eis by attending to a few neceflary circumftances. Firft, the elevation need not be very great, and lefs gas will efcape ; fecondly, the temperature may be kept down by a large current through pipes of confiderable diameter; and thirdly, jt is praéticable by various contrivances, that an interior float fhall give notice when the gas has lowered the furface of the _ water beneath it to a ceriain point, and this may either warn an attendant to pump it out, or it may difcharge an apparatus to produce the fame effect without the immediate exertion of labour each individual time. Concerning thefe and other fecondary points, I fhall not, however, enlarge ; having enough to regret from the neceflary imperfection of this defcription, taken from the converfation of the inventor, inftead of being given in his own words. W. N. Deferipiion 2 DESCRIPTION OF A NEW PADLOCK. 43 VII. Defcription of a new Padlock of Security with Combinations. By Citizen ReGnier.* Tue intention of this padlock is to fecure portmanteaus, cloak Defeription of a 7 padlock of com-= bags, and other packages in the moft complete manner, and to}; , ation, ferve occafionally as defences to the key-holes of the doors of apartments. The padlock is compofed of four circular pieces of brafs, on which are engraven the twenty-four letters of the alphabet. The four pieces are moveable on their axes by turning them with the finger in order to produce the combination by which it is opened. The combination of the manufaéturer is the word ROME ; when this word is brought intoa correé line with the two marks on the edges of the two fteel plates FF, which form the ex- ternal part of the padlock, thofe two plates can be feparated alittle from each other, and the clafp of the lock can be opened by the hinge. The fame procefs is ufed to faften it, with this difference, that the two external plates are prefled together fo as to con- fine the bow or clafp of the lock in its cell at G ; after which, the combination is to be thifted fo that the chara¢ters fhall no longer form the fame word in the before-mentioned line. The Method by which the Poffeffor may difpofe the Padlock to a& by a new Combination, which cannot be known to any other Perjon: 1. A fcrew is taken out, which pafles through the centre of the plates FF. 2. The combination which it is intended to fet afide, namely, that which opens the lock at prefent muft be duly arranged. 3. The marked circular pieces or rings muit be taken off from four plates of brafs which conftitute the central part, and together form the centre-piece of the mechanifm. 4, Laftly, The rings muft be replaced on the centre pieces, each according to the letter the poffeffor may have chofen. For example: If you would adopt the word LOCK for the combination, the letter L of the firft ring muft be placed over * Tranflated from a paper circulated by the conitructor. , or Aid Defcription of a padlock of com- hinatione DESCRIPTION OF A NEW PADLOCK, or upon a fall fteel tooth, which is attached to the firft interior cylinder; the letter O of the fecond ring on the tooth of the fecond cylinder; the letter C of the third ring on the tooth of the third cylinder; and laftly, the letter K of the fourth tooth on the fourth cylinder. By this means the word lock is fet up and becomes the come bination of the lock, and the word Rome no longer produces the difpofition of parts required for the difengagement. After this operation the fcrew mutt be replaced in the centre of the plate; this {crew does not contribute to the ftrength of the mechanifm ; but is ufed merely to allow the exaét {pace neceflary for opening the padlock, and to prevent the fepara- tivn of the rings from the central parts in the common ufe of the lock. Method of ufing this Lock as a Defence to the Key-hole of a Door. A ring ftaple A, having a wood {crew, is fixed to the door above ihe key-hole or efcutcheon of the lock. A fecond ring C is fixed perpendicularly beneath the other, A cylindrical tube of iron D, in the form of a bolt, is placed vertically in the ring of thefe ferew ftaples. At the lower end of the tube is an aperture, through which the padlock is inferted, fo that the tube or bolt cannot be raifed or taken out. By this contrivance the key-hole of the lock is completely defended, and the introduétion of a pick-lock or falfe key is ~ ‘rendered morally impoffible. For the mechanifm prefents 331,776 combinations, * forming 331,775 different obftacles, to prevent the removal of this defence by any perfon unac- quainted with the fecret of the proprietor. If it be apprehended that the word of the combination may be forgotten, it will be eafy to write and difguife it in many different ways, without any rifk of difcovery: for example, The letter L, or eleventh letter of the alphabet oe will be written 1. The letter O, or fourteenth letter - é us So, The letter C, or third letter - ~ re 2 bal Be The letter K, or tenth letter = 7 - - 10, Total (expreffed) £. 38. * Number equal to the 4th power of 24, ; This _ DESCRIPTION OF A NEW PADLOCK. AD . This little calculation will appear to any other perfon to be Defcription of a, acommon account, but it is to the proprietor a memorandum pasion es tes by which he will perfeétly recolleét that the firft letter of his combination is the eleventh of the alphabet, that the fecond is the fourteenth, and fo of the reft. REMARKS. This padlock appears at firft fight fimilar to that contrived by Cardan; but we know that his was not capable of having its combinations changed; whence it refults that the manufac- turer, the retailer, and every other perfon who may have feen it opened, can themfelves open it with the fame facility as the proprietor himfelf. The notches which produce the opening may be alfo difcovered by the feel; our lock has falfe notches cut in the centre-piece of the mechanifm which prevent the dif- covery of the real one. Laftly, The clafp of this padlock is made of hardened and tempered fteel, to prevent its being eafily cut by an ordinary file. It is annealed fo far only as to prevent its breaking. ' ; AnnoraTion. -W.N. The remaining part of this paper contains the addrefs of the inventor and vendor, C. Regnier, ci devant Jacobins, Rue Do- minmique, F. St. Germain a Paris, and alfo a certificate of ho- nourable mention, &c. from the Athenée des Arts. - The lock of Cardan confifts of the four vifible circular parts carrying the alphabet. Thefe as well as the central parts of the prefent lock are perforated half way through their centers by an hole, and quite through by a fmaller hole, in the fide of which laft there 1s a notch extended to the circumference of the larger hole. All the four pieces are placed upona central pin, which has fide projections anfwering refpedtively to the notches, but occupying the fpace of the larger hole while the lock is clofed. From this conftruéction it is evident that the lock cannot be opened unlefs every one of the notches be placed oppofite its projeGtion; that this pofition or placing is fettled by the maker, and not variable; and that the lock is liable to be opened, though not eafily, by the tentative procefs defcribed at p. 204 of our laft volume. Cit. Regnier has perfeéted the lock of Cardan by seis the fyftem of the alphabet moveable with regard to the inter- nal 46 Defeription of a padlock of com- bination. Former paper of the author, and of Monge, upon horizontal refraction. QUANTITY OF HORIZONTAL REFRACTION. nal notch at the pleafure of the poffeffor, and alfo by making groves or fmall notches on the face of each central piece, which anfwer the purpofe of the teeth recommended at the page laft quoted, by preventing the rings from being turned round while any pull is made againft the clofure. I find fome obfcurity in his defcription of the manner of connecting the central piece and the external engraved part. From the operation, I apprehend, 1. that each ring has a number of notches at its inner furface, that anfwer to the letters on its outer face; 2. that each central round piece fits the cavity of its ring, and is prevented from turning by a tooth which it lodges in one of the notches; 3. that when all the four teeth are ranged in a line between F and F, the lock will open; and therefore, 4, when any particular letter is placed over the tooth, that letter becomes the effeétive letter for its own ring. | VIII. Obfercations on the Quantity of horizontal Refraction; with a Method of meafuring the Dip at Sea. By Witttam Hype Wo utaston, M.D. F.R.S.* In a Paper which I fome time fince prefented to this Society, (printed in the Phil. Tranf. for 1800,) I endeavoured to afcer- tain the caufes, and to explain the various cafes, of horizontal refraction, which I had either obferved myfelf, or had feen defcribed by others. At the time of writing that effay, I had not met with the Mémoires fur PEgypte, publifhed but a fhort time before; and I was not aware that an account had been given by M. Monge, of the phenomenon known to the French by the name of mirage, which their army had daily opportunities of feeing, in ibeir march through the deferts of Egypt. In the perufal of this memoir, I could not fail to derive inftruétion from the information it contained; but, as the faéts related by him accord entirely with the theory that I had advanced, I was by no means induced to adopt the explana- tion that he has.propofed, in preference to my own. * From the Philofophical Tranfations for 1803. 3 The “QUANTITY OF HORIZONTAL REFRACTION, 47 The definite refleG@ing furface which he fuppofes to take Objection to ths: place between two ftrata of air of different denfity, is by no means confiftent with that continued afcent of rarefied air which he himfelf admits ; and the explanation founded on this hypothefis will not apply to other cafes, which may all be fatisfaGtorily accounted for, upon the fuppofition of a gradual change of denfity, and fucceffive curvature of the rays of light by refraétion. ‘I have fince learned that the fame fubjeét has alfo been ably theory of Monges The fubjeé& well treated by Wolte treated by Mr. Woltman, in Gilbert’s Aanalen der Phyfik “ae but I have to regret that his differtation, as well as that of Gruber, in the fame Annals, were written in a language that was unknown to me, and that I could not avail myfelf of the afliftance that I might otherwife have received from their refearches. When I formerly engaged in this inquiry, being imprefled with the advantage to be derived from it to nautical aftronomy, on account of the variations in the dip of the apparent horizon, from which all obfervations of altitude at fea muft neceflarily be taken, I fuggefted the expediency of a feries of obfervations, to be made by a perfon attentive to thofe changes of tempera- ture or moifture of the atmofphere, on which he might find the depreffion of his horizon principally to depend. I had at that time no expeétation that I could myfelf purfue this fubjeét farther to any ufeful purpofe, having little profpeét of refiding for a fufficient length of time in view of the fea, and feeing no other method by which the fame end might be accomplithed. I have, however, fince that time, found means to fatisfy myfelf, _ by obfervations over the furface of the Thames, that although Obfervations over the furface of the Thames: the quantity of refraétion varies in general with any change of » the thermometer or hygrometer, yet the law of thefe variations is not altogether fo fimple as I had hoped it might be found. I hall, on the prefent occafion, firft relate the faéts on which this opinion is founded, and which are in themfelves fufficiently remarkable, on account of the unexpected quantity of refraction obfervable over a fhort extent of water; I fhall, in the next place, fhew that the exact determination of the concurrent changes of the atmofphere are of lefs value, and their irregu- larities of lefs confequence, than I had conceived, as there isa very eafy method whereby the quantity of dip at fea may be at any time correctly meafured ; and therefore the end which I fought by indireét means, may be at ence direétly attained. The Narrative. 48 QUANTITY OF HORIZONTAL REFRACTION. Apparent diftor- ‘The firft inflance that occurred to me, of obfervable refrac pais ales tion over the furface of the Thames, was wholly accidental. over the furfice [ was fitting in a boat near Chelfea, in fuch a pofition that of the Thames. my eye was elevated about half a yard from the furface of the water, and had a view over its furface, that probably forne- what exceeded a mile in length, when I remarked that the oars of feveral barges at a diftance, that were then coming up with the tide, appeared bent in various degrees, according ‘to their diftance from me. The moft diftant appeared nearly in the form reprefented, Plate I. Fig. 1. dd being my vifible horizon by apparent curvature of the water; ab the oar itfelf in its inclined pofition ; and bc an inverted image of the por- tion be. By a little attention to other boats, and to buildings on fhore, I could difeern that the appearance of all diftant objeéts feen near the furface of the water was affeéted in a fimilar manner, but that fearcely any of them afforded images fo perfe€ily diftin@ as the oblique line of an oar dipped in the water. Thefe effects A perfon prefent at the time (as well as fome others to are diffe «nt whom I have fince related the circumftance) was inclined to froin what : ae : might be caufed attribute the appearance ‘to refleétion from the furface of the by geficction, water; but, by a moderate fhare of attention, a very evident difference may be difcovered between the inverfion occafioned by refie@lion, and that which is caufed by atmofpherical refrac- tion. In cafes of refle€tion, the angles between the objeét and image are fharp, the Jine’ of contaét between them ftraight and well defined, but the lower part of the image indefinite and confufed, by means of any flight undulation of the water. But, when the images are caufed-by refraétion, the confines of the objeét and its inverted image are rounded and indiftin@, and the lower edge of the image is terminated by a ftraight line at the furface of the water. In addition to thefe marks of diffe- rence, there is another circumftance which, if attended to, muft at once remove all doubt ; for, by bringing the line of fight near to the furface of the water, boats and other {mall objects are found to be completely hidden by an apparent hori- zon, which, in fo fhort a diftance, cannot be owing to any real curvature of the water, and can arife folely from the bend- ing of the rays by refraétion. They appear When I refleéted upon the caufes which were probably in- referrible to an ftrumental in the production of thefe phenomena, they appeared higher temperae : thie in the . referrible QUANTITY OF HORIZONTAL REFRACTION, 49 referrible to difference of temperature alone. After a fuccef- water, which — fion of weather fo hot that the thermometer, during one month “ane Snnnim iat preceding, had been 12 times above 80°, and on an average of ee et of the month at 68°, the evening of that day (Auguft 22, 1800) rane was unufually cold, the thermometer being 55°. The water power. might be fuppofed to retain the temperature it had acquired during afew weeks preceding, and, by warming the ftratum of air immediately contiguous to it, might caufe a diminution of its refractive denfity, fufficient to effeét this inverted curvature of the rays of light, in the manner formerly explained. As L was at that time unprovided with inftruments of any kind, I had it not in my power to eftimate the quantity of refraétion, or temperatures ; and can only fay that, to my hand, the water felt in an uncommon degree warmer than the air. Being thus furnifhed with an unexpeéted field for obferva- Particular ace tion, I from that time took fuch opportunities as fimilar changes 6°Mt of the ; ks : obfervations. of the weather afforded me, of examining and meafuring the quantities of refraction that might be difcovered by the fame means over another part of the river, that I found moft fuited to my convenience. The fituation from which the greater part of my obfervations were made, was at the S. E. corner of Somerfet houfe. The. view from this {pot extends under Blackfriars bridge, towards London bridge, upwards of a mile in length, and in the oppo- fite direétion through Weftminfter bridge, which is three quarters of a mile diftant. Such diftances are however by no means neceflary ; and in« deed the air over the river, in cold weather, is generally, or at leaft very frequently, not fufficiently clear for feeing diftin€lly to fo great diftances. For, fince the winds which are moft likely to effeét a fufficient change of temperature, on account of their coldnefs, are ufually from the E. or N. E. the principal f{moke of the town is then brought in that direétion, and hovers, like a denfe fog over the courfe of the river, This circum= ftance deprived me of many opportunities which the changes of the thermometer indicated to be favourable for my purpofe, and obliged me often to make ufeof fhorter diftances than I fhould otherwife have chofen, by bringing the line of fight as near as I could to the furface of the water. For this purpofe, I had a plane reflector fitted to the obje@- end of a fmall pocket telefcope, at an angle of 45°, fo that, Vou. VI.—SEPTEMBER. E when QUANTITY OF HORIZONTAL REFRACTION. when the telefcope was held vertically, it gave a horizontal view at any level that was found moft eligible. When the water has been calm, I have obferved that the greateft refrac- tion was vifible within an inch or two of its furface, and I have - then feen a refraétion of fix or feven minutes in the fpace of 300 or 400 yards: at other times, I have found it greateft at the height of a foot or two; but, in this cafe, a far more ex- tenfive view becomes neceflary. The firft meafures that I took were on the 23d of September, 1800. The water was 24° warmer than the air, and I found a refraction of about 4%, Od. 17. The difference of temperature was 3°, and the refraction 3’. Oct. 22. The water was 1]2° warmer than the air, yet the quantity of refraétion did not exceed 3’. The fmallnefs of the quantity of refra€tion upon this occa- fion, I attributed to the drynefs of the atmofphere, conjeCturing that a rapid evaporation might in great. meafure counteract that warmth which the water would otherwife have commu-~ nicated to the air, . From that time, therefore, I have noted not only the heights of the thermometer in the water and in the air, but have added. alfo the degrees of cold produced by keeping the bulb of it moiftened for a fufficient time to render it ftationary. In con- firmation of my conjeéture refpegting the drynefs of O&. 22, I have alfo, in the following Table, which comprifes the whole _ of my obfervations, inferted a column from the Regifter kept at the apartments of the Royal Society, containing the heights of the hygrometer, on thofe mornings when my obfervations were made, ‘ TABLE, QUANTITY OF HORIZONTAL REFRACTION. | BL TABLE. At 8, A.M. | a... | rater, | Diffe- | Refrac-] Cold by | Hygro- Table of obfere rence. tion. {evaporation.} meter. vations: errr | | | rrr | 1800. Sept. 23} 57 | 603° | 32° | 4 zoe 79° O&. 17} 463] 494 3 3 —— 72 221 38 | 49% | 112 | 3 -— 67 Nov. 1} 41 | 454 44 | 8 2 la 4| 432) 462 3 3- 12 72 5| 37 | 45 8 8 + 1 69 12] 442} 482 4 1+ 32 73 13] 40 | 444 4 15 2 76 1801. June 13] 50 | 63 13 9 + 5 65 221 55 | 61 6 6 +. 6 65 BUSS G2 7 6 42 65 24, 55 | 61 6 3 3 67 Sept. 8] 60 | 64 4 7 2 78 9) 64 | 642 2 5 3 7 A 10}; 58 | 64 6 7 Z 70 12 o’clock, 10] 63 | 64 1 2 From a review of the preceding Table it will be found, upon The dip of the the whole, that when the water is warmer than the air, fome Mirren aia increafe of depreflion of the horizon may be expected ; but by the water ont its quantity will be greatly influenced, and in general Sting Warmer diminifhed, by drynefs of the atmofphere. UPd ainsinimiea It appears, however, that no obfervable regularity is dedu<(more confider- cible from the meafures above given; but that the quantity, shi ihor ate on fome occafions, is far different from what the ftates of the The meafares thermometer and hygrometer would indicate. On the 9th of indicate little of siden ‘ ’ any practical September, for inftance, the difference of temperature is only jay, 2°, and the evaporation, to counteraét this flight excefs of warmth, produced as much as 3° of cold; neverthelefs, the refra€tion vifible was full 5’. In this obfervation T think that EI could not be miftaken, as the water was at the time perfectly calm, the air uncommonly clear, and I had leifure to pay par- ticular attention to fo unforefeen an occurrence. This one inftance appears conformable to the opinion enter- Solution of tained by Mr. Huddart, and by M. Monge, that, under fome ™oifture not of ; f ; much probable -eircumftances, the folution of water in the atmofphere caufes a conicquencée decreafe in its refra€tive power; but, on no other occafion have I been induced to draw a fimilar inference, E 2 The It is not likely that fo great a variation of the dip happens out at fea. Mr. Huddart’s remedy. QUANTITY OF HORIZONTAL REFRACTION. The objeét that I have at all times chofen, as fhewing beft the quantity of refraétion, has been either an oar dipped in the water at the greateft difcernible diftance, or fome other line equally inclined; and the angle meafured has been, from the point where the inverted image is terminated by the water, to that part of the oar itfelf which appears to be direétly above it. (The apparent magnitude of ec, Fig. 1. Pl. 3.) The eight firft angles were taken with a mother-of-pearl micrometer in the principal focus of my telefcope, and are not fo much to be depended upon for accuracy as the fucceeding eight. Thefe laft were meafured with a divided eye-glafs micrometer, and confequently are not liable to any error from unfteadinefs of the inftrament or objeé. From the foregoing obfervations we learn, that the quantity of refraétion over the furface of water may be very confiderable, where the land is near enough to influence the temperature of the air. At fea, however, fo great differences of temperature cannot be expected; and the increafe of dip caufed by this variation of horizontal refra€tion, it is to be prefumed, is not fo great as in the confined courfe of a river; but, if we confider that it may alfo be fubjeét to an equal diminution from an op- pofite caufe, and that the horizon may even become apparently elevated, there can be no queftion that the error in nautical obfervations, arifing from a fuppofition that it is invariably according to the height of the obferver, ftands in need of correction. The remedy employed by Mr. Huddart,* of taking two angles of the fun from oppofite points of the horizon at the fame time, and confidering the excefs of their fum above 180° as double the dip, muft without doubt be effe€tual ; but, from caufes which he affigns, it is pra€ticable only within certain limits of zenith diftance; for, where the zenith diftance is fmall, and the changes of azimuth rapid, there is required con- fiderable dexterity and fteadinefs of a fingle obferver who at- tempts to turn in due time, from one obfervation to another ; and, when it exceeds 30°. the greater angle cannot be mea- fured with a fextant, and confequently his method is, with that inftrument, of ufe only in low latitudes. , * Phil. Tranf. for 1797, p. 40. On QUANTITY OF HORIZONTAL REFRACTION. 53 On account of the difficulty attending fome of the adjuft- Objeétions to ments for the back obfervation, he rejeéts that method © Gata rleys/7 taking angles in general, with much reafon; but he has thereby ae overlooked a means of determining the dip, which I am inclined to think might be employed with advantage in all latitudes, _ without any occafion to hurry the moft inexperienced or cau- tious obferver. By the back obfervation, the whole vertical angle between but the method any two oppofite points of the horizon may be meafured at ee eae once, either before or after taking an altitude. Half the ex-arc between the cefs of this angle above 180°, fhould of courfe be the dip re- eg hori- quired. But, if it be doubtful whether the inftrument is duly adjufted, Error of the a fecond obfervation becomes neceflary. The inftrument mutt a ae be reverfed, and, if the apparent deficiency of the oppofite whole sate angle from 180° be not equal to the excefs before obtained, ™°"'s the index error may then be correéted accordingly; and, fince the want of adjnftment, either of the glaffes at right angles to the plane of the inftrument, or of the line of fight parallel to it, will affeét both the larger and fmaller angle very nearly in an equal degree, the } part of their difference will be extremely near the truth, and the errors arifing from want of thofe ad- juftments may with fafety be neglected. This method of correéting the index error for the back obfer- as firft fuggefted vation at fea, was many years fince recommended by Mr, by Ludlame Ludlam ; * yet I do not find that it has been noticed by fubfe- ; quent writers on that fubjeét, or fuggefted by any one for determining the dip; but I can difcover no reafon for which it could be rejeGted as fallacious, and I fhould hope that in prac- tice it would be found convenient, fince in theory it appears to be effeétual. The moft obvious objection to this, as well as to Mr. Hud- Whether refrac- dart’s method, is the poffibility that the refra@tion may be in Pai pose. fome meafure different in oppofite points of the horizon at the ferent bearings fame time. When land is at no great diftance, fuch an in- 2 the fame equality may be found to occur; but, upon the furface of the ee ocean in general, any partial variations of temperature can rarely be fuppofed to exift ; and it is probable, that under any circumflances, the difference will not bear any confiderable * DireStions for the ufe of Hadley’s quadrant, 1771, § 82, p. 56. proportion 54 Uncommon halos round the fune ACCOUNT OF TWO HALOS. proportion to the whole refraétion ; nor can it be thought a fufficient reafon for rejecting one correétion propofed, that there may yet remain other {mall errors, to which all methods are equally liable, but which it is not the objeét of the prefent differtation to rectify. IX. An Account of Two Halos, with Parhelia. By Sir H.C. ENGLEFIELD, Bart. F. R. S*. On the 20th of November, 1802, at two o’clock in the afternoon, going out of doors, at Richmond in Surry, I per~ ceived the fun, accompanied by uncommon halos and parhelia, The weather was fhowery, and the fky had that peculiar turbid appearance, which is the certain forerunner of heavy and Jong continued rain. The fun fhone with a faint and watery light, was very ill defined, and appeared rather elon- gated in a vertical direétion. A very denfe cloud occupied all that quarter of the horizon, and rofe up pretty near to the fun. Very heavy clouds covered the eaftern part of the heavens, extending quite to the north, and were proceeding gradually towards the fouth weft. The wind was about eaft. The altitude of the fun was 14°. The circle neareft the fun was diftant from him nearly 24°, and was about a de- gree in breadth, It was of a pale yellowifh light, but had no tendency to prifmatic colours. On ihe left hand, it extended below a line drawn through the fun parallel to the horizon. To the right, it terminated in denfe clouds confiderably above that line. The exterior circle was 48° from the fun, and it might be 14° in breadth, as it was evidently broader than the inner circle. It terminated on either hand at nearly the fame height as the interior one. It was tinged throughout with - the prifmatic colours, though only red, green, and blue, were diftinétly vifible. The red was neareft the fun, The blue very faint. ‘The brightnefs of this circle was about that of the fecondary rainbow, to abright common bow. * Royal Inftitution, II. 1. i a ACCOUNT OF TWO HALOS, 55 In a line parallel to the horizon, paffing through the fun, Uncommon there was, in the left hand branch of the inner circle, a very ¢* ai borage faint parhelion ; but in the upper point of the fame circle, there was a very bright and remarkable one. Its light was fo vivid, that it could fearcely be fteadily viewed ; and, indeed, it was rather brighter than the real fun. It was of a whiter light than the reft of the circle in which it was, and had a pearly appearance, as partaking a little of prifmatic tints. It was large, perhaps in its brighteft part near two degrees broad, very ill defined every where, but moft diffufed in the part furtheit from the fun. From each fide of the bright light pre- ceeded a bright ray, which had a double curvature very diftin&, being firft convex towards the fun, and then concave. The lower edge of thefe rays (or that neareft the fun), was tolerably well defined, the upper edge melted away into the fky, with a fort of ftreakinefs. They grew both narrower and fainter towards their termination, and they reached pretty near io the other cirele. The whole form of this parhelion and its rays, bore fo firiking a fimilitude to the body and extended wings of a long winged bird, fuch as an eagle, hovering direéily over the fun, that fuperftition would really have had little to add to the image. There was no trace of any other circle or arch in the heaveng, nor of any anthelion. It is probable, that it had been fill more beautiful before I faw it, as during the time I obferved it, its brightnefs was continually diminifhing; fome traces, however, were vifible for nearly half an hour. . The meafures which I have given muft be confidered as very rough. I had no inftrument at hand, but a fix inch pocket fe€tor. I held the joint of this as clofe to my eye as I could, and opened it, till the points of the legs coincided with the fun and with the circles that I wifhed to meafure. I am, how- ever, inclined to think, that the meafures I have given are true within a degree. The accompanying fketch, (Plate III.) oy is drawn on a {cale of 20° to an inch, from a rough draught which I made at the moment, will give a more difiiné idea of the whole ap- pearance than can be conveyed by words, A Theory 56 Theory of halos and parhelia. Variable halos produced by equal drops. The conftant halo of 23° not explained. The hypothefis of Huygens im- probable. ACCOUNT OF TWO HALOS, A Theory of Halos and Parhelia. By Tuomas Youne, IM 7b. Bo Re Ss. The explanation of the primary and fecondary rainbow begun by De Dominis, and completed by Defcartes and Newton, derives an entire and fatisfaGtory confirmation, from the perfeé coincidence of the obferved angular magnitudes, with the refult of calculations of the effeét of {phericai drops, We know that drops of water, either accurately, or very nearly {pherical, exift in great abundance in every cloud, and in every fhower of rain; and whatever their dimenfions may be, they muft neceffarily confpire in the fame general effect, of producing the fame rainbow, whenever a f{pectator is placed in a proper fituation for obferving it; confequently fuch rainbows are of very frequent occurrence. I have attempted to fhow, that for producing the phenomena of variable halos, often obfervable in hot climates, it is only neceffary that a confiderable part of the {pherules of a cloud or mift, be either accurately, or very nearly, of equal magnitude, a condition, of which the poflibility is eafily admitted from analogy, and the probability is favoured by the apparent unifor- mity of the different parts of fuch mifts as we can examine. But no fatisfaétory reafon has hitherto been affigned for the production of the halo, which in thefe climates is the moft common of all; that is, the conftant halo of 23° or 24°. The hypothefis by which Huygens attempted to explain the - produétion of halos and parhelia, are both arbitrary and im- probable. He imagined the exiftence of particles of hail, fome globular, others cylindrical, with an opaque part in the middle of each, bearing a certain ratio to the whole; and he fuppofed the pofition of the cylinders to be fometimes vertical, and fometimes inclined to the horizon in a given angle. It has already been obje&ted, that no fuch particles have ever been obferved to accompany halos; and it is, befides, highly improbable, that fuch an opaque part fhould bear the fame proportion in all the hailftones, and that the cylinders fhould have terminations fo peculiar as is fuppofed; and the moft incredible circumftance of all is, that all thefe proportions fhould be conftantly fuch, as always to produce a halo at the diftance of 23° or 24° from the fun or moon. . Tt ACCOUNT OF TWO HALOS. 57 It appears, that a much fimpler and more natural expla- nation of thefe phenomena may be deduced from the regular cryftallization of fnow in the atmofphere. Tit is well known, that the cryftals of ice and fnow, tend ah diaiile always to form angles of 60°; now a prifm of water or ice, a iat erode of 60°, produces a deviation of 23° 37’, for rays forming devi:tion of 23° equal angles with its furfaces, and the angle of deviation eee varies at firft very flowly, as the inclination changes, the flowly. variation amounting to lefs than 3°, while the inclination changes 30°. Now if fuch prifms were placed at all poffible angles of in- The cafual ar- clination, differing equally from each other, one half of them rine wale, would be fo fituated, as to be incapable oftranfmitting any light the halo. regularly by two fucceffive refraétions dire€ted the fame way ; and of the remaining two fourths, the one would refra& all the light within thefe three degrees, and the other would difperfe the light in a {pace of between 20° and 30° beyond them, In the fame manner, we may imagine an immenfe number Refraétion of prifmatic particles of fnow to be difpofed in all polibie pte ear direGtions, and a confiderable proportion of them to be fo greater halo of fituated, that the plane of their tranfverfe feétion may pafs 47%. within certain limits of the fun and the fpe@tator. Then halt of thefe only will appear illuminated, and the greater part of the light will be tranfmitted by fuch as are fituated at an an- gular diftance of 23° 37’, or within 3° of it: the limit being firongly marked internally, but the light being externally more gradually loft. And this is precifely the appearance of the moft common halo. When there is a fufficient quantity of the prifmatic particles, a confiderable part of the light muft fall, after one refraétion, on a fecond particle; fo that the effe@ will be doubled: and, in this cafe, the angle of retraétion will become fufficient to prefent a faint appearance of colour, the red being internal, as the leaft refrangible light, and the external part having a tinge of blue. Thefe concentric halos of 233° and 47°, are therefore fuf- Very fhort ficiently explicable, by particles of fnow, fituated promifcuoufly okie in all poffible ‘direQions. If the prifms be fo fhort as to form wife; and the triangular plates, thefe plates, in falling through the air, i ont tend to affume a vertical direction, and a much greater number give the hori- of them will be in this fituation than in any other. The reflec ser eoas tion from their flat furfaces will confequently produce a hori- tion 4 ey zontal circle of equal height with the fun; and their refraGtion with wings, will 5$ ACCOUNT OF TWO HALOS. will exhibit a bright parhelion immediately over the fun, with an appearance of wings, or horns, diverging upwards from the parhelion. Exp. with the For all fuch particles as are direéted nearly towards the prifm. fpectator, will confpire in tranfmitting the light much more copioufly than it can arrive from any other part of the circle ; but fuch as are turned more obliquely, will produce a greater deviation in the light, and at the fame time a defie@tion from the original vertical plane. This may be eafily underftood, by looking at a long line through a prifm, held parallel to it: the line appears, inftead of a right line, to become a curve, the deviation being greater in thofe rays that pafs obliquely with re[peci to the axis of the prifm; which are alfo defleéted from the plane in which they were paffing. The line viewed through the prifm has no point of contrary flexure, but if its ordinates were referred to a centre, as in the cafe of the halos, it would aflume a form fimilar ito that which Sir Henry Englefield has deferibed. Tho’ fnow flakes The form of the flakes of fnow as they ufually fall, is in- ee ae deed more complicated than we have been fuppofing, but may be fimple in their elements in the upper regions of the air are probably the upper more fimple. The coincidence in the magnitude of the regionss &- ob ferved and calculated angles is fo ftriking, as to be nearly decifive with refpeét to halos, and it is not dificult to imagine that many circumftances may exift, whici may caufe the axis of the greater number of the prifms to affume a pofition nearly - horizontal, which is all that is required for the explanation of the parhelia with their curved appendages. Perhaps alfo, the effeét may fometimes be facilitated by the partial «melting of the fnow into conoidal drops: for it may be thown, by the light of a candle tranfmitted through a wine glafs full of water, that fuch a form is accommodated to the produétion of an in- verted arch of light, like that which is frequently obferyed te accompany a pathelion, A Defcription POCTRINE OF PREPONDERANCE. 59 X. A Defeription of Dr. Youne’s Apparatus for illufirating the Doétrine of Preponderance*. Plate I. Fig. I. AruoucH there can be no doubt of the truth of the “pparatus of ; 4 pullies for fhew- mathematical conclufions, which have been deduced from the jng the mo ad- well known laws of motion, refpeéting the moft advantageous vantageous em employment of force in machines, yet they have, in general, blag 4) been too little confidered in pra@tical works, and fcarcely ever enforced by experimental illuftration. The apparatus con- trived for this purpofe, has been mentioned in the account of the leGures on mechanics ; its advantage is derived from the fimplicity of its operation, and the facility of obferving at once the feveral motions, which begin at the fame time, and may eafily be compared, as long as they continue. The ratio of the portions of the middle pulley, which is that of 5 to 2, is near enough to the maximum (,/2 x 1): 13 and the other ratios 3: 2 and 4: 1 are taken fufficiently different from this to fhow that the velocity of each is inferior to that of the middle pulley. The pulleys are all perforated in the axis, and move freely on a ftrong polifhed wire, fupported by two fhort arms, projecting a little from two upright pieces about three feet in length, in order that the defcending weights may proceed without interruption beyond the edge of the table, —SE An Account of an Experiment on the Velocity of Water flowing through a Vertical Pipe. By the fame Author. IT has been afferted by fome writers on hydraulics, and Whether the Yenturi defcribes ticular experiment in fi atthe oer u cribes a particular experiment in fupport of the water through affertion, that the difcharge of water running out of the bottom a vertical pipe . : : on from the bottom of a ciftern, through a defcending pipe, is nearly the fame as oF o cifern be if the ciftern were continued through the whole height, from the fame as the furface of the water to the orifice of the pipe, and thefrom an hole in : ‘ : a ciftern of the water were then difcharged from the bottom of the ciftern by total depth. a fhort pipe in any direGtion. The apparent difficulty of find- ing a caufe adequate to the effect, on the one hand, and the * In the leftures of the Royal Inftitution from whofe Journal No. 11. the prefent and next articles are taken, authority 60 CASE OF SPOUTING FLUIDS. authority of Venturi on the other, made it defirable that the experiment fhould be repeated ; and an apparatus Fig. III. Plate I. was conftruéted, in the houfe of the Royal Inftitution, for performing it in a fimple and fatisfa€tory manner. The ciflern employed was a cube of nine inches: clofe to the bottom a cylindrical tube was inferted, in a horizontal direc- tion, nine inches in length, and half an inch in diameter; an- other tube, of exaétly the fame dimenfions, was provided with a flat funnel at its upper end, and its lower end was fitted to flide inacollar placed in one of the upper angels of the ciftern, Experiment fo that it was fupported in a vertical pofition. Water was poured into the funnel, as faft as it could be tranfmitted through the tube, and, as the furface of the fluid rofe in the ciftern, the vertical tube was drawn up, fo that its lower orifice was barely immerfed in the water. It was expected, that if the velocity of the water in the vertical tube were equal to the velocity correfponding to half its length, the water in the ciftern would ftand at the height of four inches and a half, or one half of that length, and that the preffure of this head of water would generate, in the water flowing through the horizontal tube, nearly the fame velocity as the column of water would acquire in its defcent through the vertical tube: the friétion and refiftance being in both cafes the fame. fhewed thecon- But the refult was far different, and it fully confirmed thé cae truth of the received theory: for the water rofe in the ciftern to the height of eight inches, which was very nearly the length of the tube. It is true that the water had already fome velocity when it entered the funnel; but moft of this muft have been loft by refleGion from its fides and bottom ; and the quantity . of air bubbles, that were unavuidably carried down with the water, muft have fully compenfated the little that remained. The entire ad- ‘It appears therefore, that we are to confider this effeé in a hering column in light fomewhat different from that in which it was placed in sion ner 3 the leGlures on hydraulics. The water acquires all its velocity, active upon the in confequence of the preffure of the atmofphere aéting jointly ean a2 with its cohefion, in a very {mall fpace at the entrance of the ducesthevame- tubel: confequently, during the whole time of its defcent it effect as an head acquires no new motion, and the whole force of its gravitation of that height. : ; : muft therefore be at liberty to aét in any other way; hence the whole column produces the fame degree of preflure as if it were at reft, and caules the atmofphere to prefs on the water above SIMPLE EUDIOMETRIC APPARATUS. Of above it in proportion to its whole height, in the fame manner as if the preffure were derived in any other way from an equal column of water; and the cafe is reduced to a perfe& analogy with the preffure of a head of water of this height, fince the air aGts upon the particles entering the tube in the fame man- ner as the water does in more common cafes. Had the refult of the experiment been different, it would have been an ex- ception to the general principle of the prefervation of living force, or the equality of the potential afcent to the aétual. defcent; for, the water moving with the velocity due to half the height only, would have been capable of afcending but to half the height. a S| XI. Account of a funple Eudiometric Apparatus conftructed and ufed by Dr. T. C. Hope, FL R.S. Edin. &e. &e. Since the difcovery of the uncertainty with which the ap- The uncertainty plication of nitrous gas to atmofpheric air, and other mixtures °f eudiometrical containing oxigen is attended, it has been found defirable to WER ee ae prefent folid or liquid fubftances for the abforption of that prin- tenders the ufe ciple. This on firft confideration may feem at leaft as eafy to Adib laances be done as to mix two gafes ; but it is by no means fo, becaufe fary. the liquids in particular poffefs a degree of chemical aétivity which readers it inconvenient to immerfe the hands in them, or to expofe their furface to the open air. Dr. Hope, whom I had lately the pleafure of feeing in town, mentioned an ap- paratus he ufes in his leétures and experiments, which is at once fimple and effeétual, and I am happy in his permiffion to defcribe it in this place, A Fig. 3, Plate IV. reprefents a bottle which may be 12 Apparatus by inch in diameter, and 22 inches in length, having a neck and nip pay ftopper at D, and another neck as ufual at C, into which laft without incon- the neck of the bottle or body B, is fitted by grinding. This venience. laft was made of the fame diameter as the bottle, but feven or eight inches long. B contains the gas, and A the liquid; for example, folution of hydrofulphuret. When B is thus con- neéted with A, the compound veffel may be inverted and agi- 4 tated ; 62 The apparatus fimply ind highly conve- ricnt. Metals burned in nitrogen, &c. by galvanifm. - ReduGion of titanium. SCIENTIFIC NEWS. tated ; and the liquid will flow into B, where it will abforly the oxigen, and form a partial vacuum. If this circumftance be found, or apprehended, to prevent the complete or rapid abs forption, the veffel A may be plunged beneath the furface of common water, and the ftopper D flowly opened. The pref- fure of the atmofphere will then force in a quantity of water, which will dilute the hydrofulphuret, but not fufficiently te prevent the completion of the procefs. The veffel B muft be graduated to fhow the dimenfions of the refidue, or otherwife this refidual gas may be transferred into a veffel exprefsly gra- duated for meafuring gafes. By this fimple and elegant apparatus we fee that the liquid is economized, and the facility, neatnefs, and precifion of ex- periment infured. The fize here mentioned is very well adapted to the purpofes of public demonftration; but it is almoft needlefs to remark, that it may be made confiderably f{maller without depriving it of its utility and excellence. P. S. While reading this proof, I have received a line from Dr. Hope, by which I am very forry to find that the fketch I have given is not accurate; but as it is now late in the month, and the figure is engraved, I fhall be careful to give another engraving with the obfervations he may favour me with. W. N. SCIENTIFIC NEWS. Combuftion of Metals in non-refpirable Gafes, by means of Gal« vanifin.® Proressor Tromfdorff has noticed that metals are come buftible by means of the galvanic {park in hidrogen, ammo- nia, nitrogen, nitrous and carbonic acid gafes, Reduction of the Oxide of Titanium. Profeffor Lampadius has fucceeded in reducing to the me- tallic flate by means of charcoal only, the oxide of titanium, obtained by decompofing the gallate of titanium by potafh or foda. The metallic titanium is of a dark copper colour; it * Tromfdorff’s Hiftory of Galvanifm and its chemical agency, p> 122, has SCIENTIFIC NEWS. 63 has much metallic brilliancy, is brittle, and poffeffes in {mall {eales a confiderable degree of elafticity. It tarnifhes on ex- pofure to air, and becomes eafily oxided by heat. It then acquires a blueifh afpect. It detonatés with nitrate of potafh, and is highly infufible. All the denfe acids aét upon it with confiderable energy. Scherer’s Journ. 1X. p. 49. p. 72+ On the Precipitability of the Oxide of Bijmuth. Mr. Buckholtz has found that the folution of bifmuth pre- Solution of bife pared in the cold is alone decompofable, by a’ copious addition muth by heat not of water, but that no fuch effect takes place in the folution aa ae prepared by means of heat. He has alfo noticed that a folution of this metal prepared in thec olde, depofits its oxide ina cryf- talline form merely by warming the folution gradually. Scherer 1X. p. 73. New Method of preparing phofphate of Soda. Mr. Funcke, apothecary at Linz, inGermany, has difcovered Preparation of a new method of preparing phofphate of foda, in a more at of economical, expeditious and eafy manner, than any of the proceffes hitherto made ufe of by manufaéturers or chemifts. His procefs confifts, in faturating the excefs of lime contained in calcined bones with dilute fulphuric acid, and then diffolv- ing the remaining phofphate of lime in nitric acid. To this folution, he adds a like quantity of fulphate of foda, and then recovers the nitric acid by diftillation. The phofphate of foda is then feparated from the fulphate of lime, by the affufion of water, and cryftallization in the ufual manner. Scherer IX. 59. REMARK BY THE TRANSLATOR. (A.) This procefs feems to be much preferable to that now in ufe, viz. to decompofe the bones of animals burned to whitenefs, by fulphuric acid, and then prefenting foda to the difengaged phof- phoric acid. For the phofphate of lime cannot be completely decompofed by the affufion of fulphuric acid ; on account of this acid forming inftantly a portion of fulphate of lime: the liberated phofphoric acid then produces with the remaining undecompofed portion of phofphate of lime, a fub-phofphate of lime, which cannot be decompofed by fulphuric acid, and which together with the fulphate of lime already produced, forms an 3 unmanageable 64 SCIENTIFIC NEWS. unmanageable and bulky mafs. And again if to this mafs, wafhed out with water as well as poffible, carbonate, of foda be now prefented, a partial decompofition will only be effeéted, for it is the excefs of the phofphoric acid of this falt only, which in that cafe forms the article fought. The remaining portion of phofphoric acid remain united to the lime, in the form of phofphate of lime. The above procefs is therefore evidently better. Sulphate of Soda prepared from Sulphate of Lime. Sulphate of foda This method confifts in making into a pafte witha {ufficient from gyplum. quantity of water, eight parts of burned.gypfum, or fulphate of lime, five of clay, and five of common falt. This mixture is burned ina kiln or other convenient oven, and then ground to powder, diffufed in a fufficient quantity of water, which after being ftrained and evaporated, is fuffered to cryflallize. Scherer 1X. 61. A JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, AND TAE . ARDS. OCTOBER, 1803. ARTICLE «I. Analyfis of the Egyptian Heliotropium; a Mineral lately imported from that Country. By Frepericx Accum, Praétical Chemift, and Teacher of Chemifiry. Communicated by the Author. A PARTICULARLY beautiful {pecies of filicious ftone Beautiful filice- has lately been imported from Egypt, which was ftated in the 04S fone of a green colOur letter of the perfon who fent it, to poffefs the peculiar property ane Egypte of refle€ting the rays of the fun red, when immerfed in water ; and when taken out of this fluid to exhibit the figures of the fun and of the moon, when viewed in a particular direétion. But as none of the purchafers of this mineral could make out thefe fingular properties, the price fixed on the article was confiderably diminifhed, and the ftone fold at a cheap rate, The beautiful green colour which it: poffeffes, and the capabi- lity of receiving a high polifh, together with the facility of cutting it, has neverthelefs rendered it a convenient article for being worked into different objeéts of fancy and ornament. The colour of this ftone is a fine apple-green. It is very External appear- hard, and cannot be fcratched, but with the point of a good f2°° andere pen-knife. Its fraéture is even and free from all afperities. It breaks with very fharp edges, and its texture is very com- paét. It is femi-tranfparent when in pieces not exceeding halfan Vor... VI.—OcrToseEr, 1803, F inch 66 EGYPTIAN HELIOTROPIUM. inch in thicknefs. It ftrikes fire with fteel, and breaks into acute angular irregular pieces. Its fpecific gravity is 2,708. The ftone is fold by the venders by the name of Egyptzan Heli otropium. Its nature will be more clearly deduced from the following examination : Analyfis. Analyfis. An entire polifhed piece of the ftone, weighing 250 grains, ee prea was expofed to a white heat, ina wind-furnace, for two hours, sherri with and then fuffered to cool. The original green colour of the white and yellow mineral, was changed during this procefs to a chocolate brown, ine eas with fnow white and lemon yellow veins, The polith of the 1-21f part. {tone was not injured, but its weight was diminifhed 12 grains. Diffufion of the Five hundred grains of the ignited ftone were finely pulver- powdered ftone jzed, and mixed with 2000 grains of potafh, diffolved in alike in fourparts pot- : eee Ri he aq d (; afh, fufion, fo- Quantity of water. This mixture was evaporated to drynefs lution of the in a crucible of platina, and expofed to heat, gradually in- mafs in watery Greafed to whitenefs, for one hour. During this operation the yather turbid. : : : Bh mixture fufed quietly, and exhibited when cold, a homogene~ ous opake mafs, of a reddifh colour. This mafs was covered with water, and after having been expofed to a gentle heat, a folution of it was effeéted in that fluid. Saturated with This alcaline folution was a little turbid, and could. not be eohain dv isi rendered tranfparent by repeated filtration. I faturated it with Dilution with muriatic acid, a white precipitate fell down, the whole.fluid waters acquired a reddifh hue, and affumed a gelatinous confiftence. The latter could but difficultly be dimmifhed, by a copious ad- mixture of water. Evaporation In order to colleé the precipitate which was diffufed through nearly todry- the fluid, the whole was evaporated nearly to drynefs, and then nefs, addition of = ; Pane ; A : dilute muriatie transferred into muriatic acid, diluted with fix times its quan- - Stags tity of water, and afierwards filtered. The precipitate, after ate LLeXs e wi? . 5 ° ° : having been wathed, dried, and ignited, weighed 365 grains. It was pure filex. ; By iL Refidual fluid The fluid trom which thefe earths had been feparated, to- eoncenirated - gether with the water expended for walhing it, I concentrated costa by evaporation to about + Of its original bulk, and then fatu- of :potath. rated it with aheated folution of carbonate of potath in excefs. _ The white precipitate which was depofited, I transferred into a tik containing muriatic acid; a brifk effervefcence enfued,. but no perfect folution could be effe&ed, by either this, er any other ae EGYPTIAN HELIOTROPIUM, 67 ‘ether acid employed. It was therefore filtered, and the info- luble part collected: This infoluble refidue was of a fine red Infoluble (red) colour, and harfh to the touch. It weighed 22 grains. But Portion boiled E i nee MO): ’ with muriatic after having been boiled in muriatic acid; it loft $ grain, and acid gave a little acquired a perfeét white colour. The acid made ufe of for iron» andleft . . . AICX» that purpofe proved to have {tripped it of iron to that amount. It was therefore a portion of filex which had eluded the firft procefs employed for feparating this earth. _ The muriatic folution from which this filicéous éarth had The faft muria- been feparated, I mingled with a folution of carbonate of t< lution : i a treated as before. potafh, till no further turbidnefs enfued: ‘The obtained pre- cipitate was transferred after repeated ablutions in water, into a boiling folution of potath, and digefted in that fluid for one hour. The mixture was then diluted with water, and the in- foluble part feparated by the filtre. The alcaline folution was faturated with muriatic acid, and The alcaline fog decompofed by carbonate of ammonia in excefs; the precipi- tion was de- | ; q x compofed by tate obtained by this means, after having acquired a confider- carbonate of ame able confiftence, was digefted in acetous acid, and examined eae and di- . € Cce= for magnefia, but no veftige of fuch earth could be deteéted ae . Tt was therefore dried and ignited, its weight amounted to 204 and the {olution : contained no grains. ae ; magnefia, but The infoluble refidue from which this earth had been fepa- only alumines rated, was again diffolved in muriatic acid, and into this folu- st sat as : He. Wee . : aken up by t tion I dropped liquid ammonia till the odour of the latter con- sc-tous seid oe fiderably predominated. A brown flocculent precipitate fel] again diffolved . down, which was collected, wafhed in liquid ammonia, and pee te iad boiled for a few minutes in a folution of potafh. It was then excefs of ammo-~ P : transferred into a {mall retort, and nitric acid affufed upon it, his jean which was again diftilled off from it repeatedly. The retort after perfe@ fe- was laftly heated to a dull rednefs. The precipitate now P*ation of all ‘ z acid, and com~= weighed 29 grains. plete oxidation The fluid from which this precipitate had been obtained, by ae : together with the folution of potath made ufe of for boiling it, a eid was then mixed with muriatie acid, and afterwards decompofed The fluid from ; a : which the iron by the addition of carbonate of potath. The product obtained, nated fens eflervefced with muriatic acid, and yielded fulphate of lime on rated was mixed eflaying a fmall quantity of it by fulphuric acid. It was theres With mur. acid : . Rene E and decompofed fore dried, and expofed toa white heat, after which its weight by carb. potath. was 56% grains, Lime fell down. F2 The “at 6s EGYPTIAN HELIOTROPIUM. The refiduary fluid was further examined in the ufual man=' ner, but no other fubftance could be found, but what had been introduced during the different procefles made ufe of in this examination, The analyfis of the mineral being therefore compleated, from which it appears that 500 grains of the Egyptian heliotropium contain, Component Silex - - - - - 365 grains parts of Egyp- Alumine - - = = 205 tian heliotropi- Oxide of Iron 4 G ae 29 & um. Lime jo senility ssiv be 56% Water - - sii Mugs) 1a 495 Lots” «75 500 Old Compton-Street, Soho, Sept. 8th, 1803. P. §. In my paper on the compound of phofphorus and ful- phur in your laft Journal (Auguft) I obferve a typographical error, p. 5.1. 22. which materially affeéts the fenfe, and which I will thank you to correét, namely, for 3, read =, part. FA. II. Method of clofing wide mouthed Veffels intended to be kept from communicating with the Air. Ina Letter from ANTHONY Caruisie, Efq. To Mr. NICHOLSON Dear Srr, Clofure of wide Gy is frequently defirablesto clofe the openings of wide-mouths sonia ik ed veffels intended to contain fubftances which would be in- tomical prepara-jured by free expofure to the atmofphere, or to evaporation. ie ar The prefent obfervations, however, originate in attempts made to improve the art of preferving anatomical preparations.—: The moft ufual liquids employed for what are termed “ wet preparations,” are weak ardent fpirits, and diftilled oil of tur- pentine, METHOD OF CLOSING WIDE-MOUTHED VESSELS. 69 — pentine, to which may be added an aqueous folution of hy- drargyrus muriatus, or mercury corrofive fublimate in the pro- portion of twenty grains of the latter to a pound of pure water. The methods ordinarily adopted for clofing glafs veffels ufed Ufual methods. for thefe purpofes, have been ground glafs ftoppers, well foaked bladders with a middle plate of thick fheet lead, to keep the top level, and plates of glafs luted with glaziers putty. The objeétions to thefe methods are found by experience to Obje@ions to be fufficient to induce the trial of others. The ground glafs each feverally. ftoppers are feldom air-tight, but when they are, it happens that by the accumulating of particles of duftin the fitting, the ftopper becomes in a few years immoveable. Where oil of turpentine is employed, the {topper becomes fixed by hardened turpentine. The ftopping with bladders and fheet lead is li- able to fuch repeated changes of preffure within and without, by the alterations in the expanfion of the contained liquids from variations of temperature; that the cohefion of the bladders are eventually deftroyed ; add to this, that fuch preparations cannot be taken out of the veffels for examination, or the li- quor renewed, without the trouble of a new ftopping. The plate of glafs with putty is feldom air tight, but when it is fo, the ftopping is liable to the fame objeétion which was ftated laftly againft the bladders. The method [ have now adopied, is to have a glafs jar with New ae by a groove half an inch deep round the outfide of the top or ae ake mouth, and a glafslid, like that ufed by confeétioners in their into a groove fhow glaffes, the lid fitting loofely into the groove is rendered baniual eae air tight by hog’s lard, a fubftance never quite fluid at the higheft temperature of this climate, and always foft enough in the cold feafon to admit of removing the lid or top. The firft glafs of this kind was made to my order by Mr, Parker in Fleet-ftreet, to contain twenty ounce meafures of water, and the coft was five fhillings. A fimilar adjuftment for the lids of earthen jars, to contain pickles, preferves, &c. feems both eligible and eafy in practice. See Plate V. Fig. 2. Iam, Dear Sir, Your obliged Friend, A. CARLISLE. Soho-Square. Extrad 70 Catt iron lying thirty years at the bottom of the fea was ox- ided, Not uni- formly, but in yeins. A cannon funk ina fhip burned at the evacua- tion of Toulon was oxided only in the middle. CHANGES OF CAST IRON. iif. Extra& of a Letter from Toulon to General le Vavaffeur, Infpector of the Materials of the Guns of the French Navy, on the Changes which Caft Iron undergoes by remaining long in the Sea.* An obfervation I have never heard explained is, that caft iron, which has lain a long time at the bottom of the fea, is not equally oxided throughout. I formerly faw acannon weigh- ed up, .after it had been funk thirty years, which was fo much oxided in veins, that I could run a knife into fome places, while the metal clofe by was impenetrable; and on carrying the knife beyond this hard vein, it entered as before. A gun has juft been weighed up here (at Toulon,) belonging to one of the thips burnt when the Englifh evacuated the city, The middle is fo uniformly oxided, that a large piece may be cut — off witha hatchet. ‘Toward the breech, and toward the mouth, the metal appears to have loft nothing of its hardnefs. Can this difference be afcribed to the contaét of the fubftances in which the gun was buried underneath the water? Its pofition at the bottom of the fea not being known, we can form no cane jectures on this point. For my part [had imagined, from the hard veins of the cannon mentioned above, that its metal had’ intermixed with it fubftances on which falt water could not act. The gun lately taken out of the fea appeared more ho- mogenous, but I cannot frame any fatisfactory explanation of the faét.+ * Annales de Chimie, V. 139. ; + It is probable, that the laft cannon, as it belonged to a fhip that was burned, had part of it heated to fuch a point, when it.fel] into the fea, as would occafion it to be oxided in a higher degree than the others. It appears to me, more difficult to explain the different veins exhibited by the former cannon. Note of General le Vavaffeur., | , IV. On ANTIQUITY OF THE INVENTION OF GUN-POWDER, 71 IV. On the Antiquity of the Invention of Gun-powder, and its firf? Ap- plication to Mihtary Purpojes. By Mr. Wirc ies.* THe period of the invention of Gun-powder, and its firft application for the purpofe of artillery, has not yet been accu- rately afcertained, Though there are many accounts which have been given concerning the invention of this deftructive ; compound, yet none of them ftate their authorities. The un- certainty concerning the invention of gun-powder feems merely to be owing to the want of proper documents. The moft Hiforical faés fummary accounts the author of this paper could find, are con- papal tamed in two Effays, the one written by Gram, the other by gunpowder, and Tremler. The firft account contains the hiftory of the inven, its ule in war. tion of gun-powder in Europe, and its firft application in Denmark ; the latter comprehends both the invention of pow- der, and the ufe of guns among the Europeans, According to the opinion of Gram, gun-powder was al- ready known in Europe about the year 1340. Tremler, on the contrary, endeavours to prove, that no author of credit has pofitively fhewn that it was known before the year 1354. Thefe authors, therefore, differ only 14 years, refpe@ing the period of the invention. Being the other day, fays Mr. Wiegleb, in fearch of fome documents depofited in the ar- chives of this town (Langenfalze), I happened to meet with ihe annual account of the expences of the town for the year 1378. This account contains a fpecification of different arms, viz. pikes, bows, crofs-bows, arrows, guns and gun-powder. The following articles particularly fixed his attention : 1. One gun. 2. One gun andonecharge of lead. 3. One gun and one charge of lead, 4. Two guns and two charges of lead. 5, One gun and one charge of lead. 6. Two guns and three charges of lead. Befides thefe articles, the following charge was made in the account ; Pro Pulveribus, 35 thillings, Pre Pulveribus quos domini emerunt ad Pyxides, 3 fhillings, Pro duabus Putellis ad Pyxides, 3 fhillings. © From the German of Crell’s Annales, ve xx. Pe 6. tf \ 72 ANTIQUITY OF THE INVENTION OF GUN-POWDER,. Hittorical fats If we confider that guns, powder, and lead, are here a. determine th€ charged, it is obvious that by the word pulvis, gun-powder rf invention of i unpowder, and muft be underftood ; and by patellis, guns muft be meant. its ufe in war’ From thefe documents we are led to believe that guns and gun-powder were known already before the year 1378. And it is more than probable that they were not purchafed that year, but had probably been ufed before that time. For guns were too expenfive for fingle individuals and fmall towns at that time; and on that account, the place in which I met with the faid documents was very probably provided with guns many years after the invention of them. That this muft have been the cafe becomes obvious from the following ob- fervation: Achilles Gefner, the Hiftorian of Augfburg, who wrote a Latin Chronicle at the beginning of the 16th century, fays,* ‘* Three large cannons were caft at Augfburg in the “ year 1378, the largeft of which difcharged a ball of 127 “¢ pounds ; the fecond a ball of 70 pounds, and the third a «« ball of 50 pounds, at a diftance of 1000 paces.” Herman Corner, who lived at the end of the 14th century, relates that the inhabitants of Lubec affifted the Emperor Charles, who befieged the caftle of Dannenberg, with 600 armatis cum duabus machinis. Bombardae enim pro tunc non erant tta communes, utt nunc funt: From hence it is evident that the 600 machines were nothing but bombardae, or guns. Another remarkable document the author of this paper met with was the fentence of death of Nicolaus the Bold, who fupplied the enemy with two barrels of gun-powder, in the year 1372. In this fentence it is clearly expreffed, that the gun-powder was made up of faltpetre and fulphur. In the fame year, the Corporation of Augfburg ordered to have caft, twenty cannons of metal, at the great expence of fifty pence, Thefe cannons were intended to be ufed againft their neigh- bours, the Bavarians. Petrarch, born 1304, ftates, in his work + publifhed 1374, Gav. Habeo machinas, ingentia fuxa torquentes. Rav. Saxa torquere furiofum eft. Gav. Habeo machinas et balliftas innumeras. Raz. Mirum nifi et glandes Aeneas quae flammis ejectis hor= rifon sone tru jacuntur. Non erat fates de coelo tonantes ira * Annales Augfburgenfes. + De Remediis utriu{que fortunae, 4. Dei ANTIQUITY OF THE INVENTION OF GUN-POWDER. 713 Dei immortalis, homuncio? O credulitas junéia fuberbiae. De Hiftorical fa&s terra etiam tonuzfet : Non immutabile fulmen ut Maro ait humana parents rabies tmmitata eft, et quod e nubibus mitt? folet, ligneo quidem, gunpowder, and fed tartareo mittitur infrumento, Evat haec pefiis nuper rara ut is ¥f& in ware cum ingenti miraculo cerneretur, nunc ut rerum pefimarum do- ciles funt anime, ita communis eft ut unum quodlibet genus ar- morum. We fhall be lefs furprifed that cannons and guns were made of wood ; even inthe 15th century guns were bound with iron hoops. : In the year 1365, Margraff Frederick, of Meiffen, at- tempted to ftorm the town and caftle of Einben with flings, battering rams, and other machines, then made ufe of in be- fieging towns. Rothe, who mentions this in his Chronicle of Thuringen, farther relates that the Duke Albert was in poffeffion of a gun which he himfelf ufed at the fiege, for fhooting into the works of the enemy. It was, fay this author, the firft gun ever feen in that country. In another document is ftated, that anno Domini, millefimo tricentefimo fexayefimo, confiftortum urbis Lubecenfis in toto com- bujfium eft, per negligentiem illorum qui pulveras pro bombardis parabant. | The fame fire is mentioned by Herman Corner, a. native of Lubeck. His words, as taken from the Chronicle ‘of Lubeck, are as follows: Con/fiftorium urbis Lubecenfis incen- Sum eft, et combuftum per negligentiam illorum qui pulveres pro bombarbis, five petraries parabant, fecundum Chronicam Lube~ cenfem. Cum enim praedictas parafent locabant cos in quodam loco confiftoris non caute cuftoditos ab agne. Pulveres ergo per incue riam noéte accenfiy domum ipfam fuccenderunt, ad antequam ex- tingut potuiffent, ewm in cineres redegerunt, Confequently gun- powder muft have been prepared already at Lubeck about the year 1360. In the year 1359, a war broke out between the kings of Caftile and Arragonia; in which the latter made ufe ofa large gun, with which he did much damage to the veffels of the king of Caftile ; for he fhot down with it the mafts and rigging, and killed many men by only two fhots. Peter Divacus commemorates, that in the year 1356 the inhabitants of Lyons in Brabant purchafed 12 guns (bombar- .dae) which were called thundering guns, or blunderbuffes, - ab horrendo fragore. 74 Refearches of Bergman on Calamines. Hauy’s opinon that they are pure oxides, ‘Experiments, ony Calamine from Bley berg. External cha- racterse CHEMICAL ANALYSIS OF SOME CALAMINES. Vv. 4A Chemical Analyfis of fome Calamines. By JAMES SMITHSON, Esa. F.R.S. P.R.S. From the Philofophical Tranfac- tions for 1803. NorwitHsta NDING the experiments of Bergman and others, on thofe ores of zinc which are called calamine, much un- certainty ftill fubfifted on the fubjeét of them. Their conftitution was far from decided, nor was it even determined whether all calamines were of the fame fpecies, or whether there were {fe- veral kinds of them. The Abbé Hauy, fo juftly celebrated for his great oan: ledge in cryftallography and mineralogy, has dhe: in his late work *, to the opinions he had before advanced +, that calamines were all of one f{pecies, and contained no carbonic acid, being a fimple calx of zinc, attributing the effervefcence which he found fome of them to produce with acids, toan ac- cidental admixture of carbonate of lime. The following experiments were made to obtain a more certain knowledge of thefe ores; and their refults will: thow the neceflity there was for their farther inveftigation, and how wide from the truth have been the opinions adopted con- cerning them. Calamine from Bleyberg. a. The fpecimen which furnifhed the fubjeét of this article, was faid by the German of whom it was purchafed, to have come from the mines of Bleyberg in Carinthia. It was in the form of a fheet ftalactite, fpread over fmall fragments of limeftone. It was not however at all cryftalline, but of the dull earthy appearance of chalk, though, on coms parifon, of a finer grain and clofer texture. It was quite white, perfectly opaque, and adhered to the tongue; 68.0 grs. of it, in fmall bits, immerfed in dittilled water, abforbed 19.8 grs. of it, = 0,29. It admitted of being {craped by the nail, though with fome. difficulty: fcraped with a knife, it afforded no light. ® Traité de Mineralogie, Tome 1V. + Fournal des Mines. Noi 32. 6$.1 grs. | e CHEMICAL ANALYSIS OF SOME CALAMINES, 75 68.1 grs. of it, broken into fmall pieces, expelled 19.0 grs, Specific gravity. of diftilled water from a ftopple bottle. Hence its denfity = 3.584. In another trial, 18.96 grs. at a heat of 65° Fahren- heit, difplaced 5.27 grs. of diftilled water; hence the denfity = 3.598. The bits, in both cafes, were entirely penetrated with water. : b. Subjeéted to the aétion of the blowpipe on the coal, it be- Blowpipe affays« came yellow the moment it was heated, but recovered its priftine whitenefs on being let cool. This quality, of temporarily changing their colour by heat, is common to moft, if not all, metallic oxides ; the white growing yellow, the yellow red, the red black. Urged with the blue flame, it became extremely friable ; fpread yellow flowers on the coal; and, on continuing the fire no very long time, entirely exhaled. If the flame was direéted againft the flowers, which had fettled on the coal, they fhone with a vivid light. A bit fixed to the end of a flip of glafs, watted nearly as quickly as on the coal. It diffolved in borax and microcofmic falt, with a flight effervefcence, and yielded clear colourlefs glaffes ; but which became opaque on cooling, if over faturated. Carbonate of foda had not any action on it. ce. 68.0 grs. of this calamine diffolved in dilute vitriolic acid Solutions in the with a brifk effervefcence, and emitted 9.2 grs. of carbonic icone Denk acid. The folution was white and turbid, and on ftanding gave only falts of depofited a white powder, which, colleGted on a {mall filter pe Le ‘ of gauze paper, and well edulcorated and let dry, weighed only 0.86 grs. This fediment, tried at the blowpipe, melted firft into an opaque white matter, and then partially reduced into lead. _ It was therefore, probably, a mixture of vitriol of lead and vitriol of lime. The filtered folution, gently exhaled to drynefs, and kept over a fpirit-lamp till the water of cryftallization of the falt and all fuperfluous vitriolic acid were driven off, afforded 96.7 grs, of perfectly dry, or arid*, white falt. On re-folution in water, and cryftallization, this faline matter proved to be wholly vitriol * Dry, as oppofed to wet or damp, which are only degrees of each other, merely implies free from mechanically admixed water. Arid, may be appropriated to exprefs the ftate of being devoid of combined water, of ~I Dy The calamine contained oxide of zinc, car- bonic acid, and water, Somerfetthire calamine. CHEMICAL ANALYSIS OF SOME CALAMINES. of zinc, excepting an inappretiable quantity of vitriol of lime in capillary cryftals, due, without doubt, to a flight and accidental admixture of fome portion of the calcareous fragments on which this calamine had been depofited. Pure martial pruffiate of tartar, threw downa white precipitate from the folution of this falt. In another experiment, 20.0 grs. of this calamine afforded 28.7 grs. of arid vitriol of zinc. d. 10 grs. of this calamine were diffolved in atidaat marine acid, with heat. On cooling, fmall capillary cryftals of muriate of lead formed in the folution. This folution was precipitated by carbonate of foda, and the filtered liquor let exhale flowly in the air; but it furnifhed only crvftals of muriate of foda. e. 10 grs. diffolved in acetous acid without leaving any refi- duum. By gentle evaporation, 20.3 grs. = 2.03. of acetite of zinc, inthe ufual hexagonal plates, were obtained. Thefe cryf- tals were permanent in the air, and no other kind of falt could be perceived amongft them. Neither folution of vitriolated tartar, nor vitriolic acid, occa- fioned the flighteft turbidnefs in the folution of thefe cryftals, either immediately or on ftanding ; a proof that the quantity of lime and lead in this folution, if any, was exceffively minute. f. A bit of this calamine, weighing 20.6 grs. being made red hot in a covered tobacco-pipe, became very brittle, dividing on the flighteft touch into prifms, like thofe of ftarch, and loft 5.9 | grs. of its weight = 0.286. After this, it diflolved flowly and difficultly in vitriolic acid, without any effervefcence. According to thefe experiments, this calamine confifts of, Calx of zinc - - - 0.714 Carbonic acid - - = 0.135 Water - “ - 2 OSE 1.000. _ The carbonates of lime and lead in it are more accidental admixtures, and in too fmall quantity to deferve notite. Calamine from Somerfetfhire. a. This calamine came from Mendip Hills in Somerfethhire. It had a mammillated form ; was of a denfe cryftalline tex- ture ; femitran{parent at its edges, and in its fmall fragments ; and upon the whole very fimilar, in its general appearance, to calcedony. Tt CHEMICAL ANALYSIS OF SOME CALAMINES. Va It was tinged, exteriorly, brown ; but its interior colour was a greenifh yellow. It had confiderabie hardnefs; it admitted however of being Charaéters. {craped by a knife to a white powder. 56.8 grs. of it difplaced 13,1 grs. of water, at a temperature of 650 Fahrenheit. Hence its denfity = 4.336. b. Expofed to the blowpipe, it became opaque, more yellow, Blowpipe affays, and friable; {pread flowers on the coal, and confequently vola- tilized, but not-with the rapidity of the foregoing kind from Bleyberg . . It diffolved in borax and microcofmic falt, with effervefcence, yielding colourlefs glaffes. Carbonate of foda had no aétion on it, c. It diffolved in vitriolic acid with a brifk effervefcence ; eshitens and 67.9 grs. of it emitted 24.5 grs. = 0.360, of carbonic acid. This folution was colourlefs; and no refiduum was left. By €vaporation, it afforded only vitriol of zinc, in pure limpid cryftals, " d. 23.0 grs. in {mall bits, made red hot ina covered tobacco- Pipe, loft 8.1 grs. = 0.352. It then diffolved flowly and diffi- cultly in vitriolic acid, without any emiffion of carbonic acid ; and, on gently exhaling the folution, and heating the falt ob- tained, till the expulfion of all faperabundant vitriolic acid and all water, 29.8 grs. of arid vitriol of zinc were obtained. This dry falt was wholly foluble again in water ; and folution of pure martial pruffiate of foda occafioned a white precipitate in it. This calamine hence confifts of, - Component Carbonic: acid fe - « 0.352 parts, Carboni¢ ‘ . acid and oxide Calx of zinc - . 4 - 0.648 of zinc. 1.000. Calamine from Derbyfhire. a. This calamine coafifted of a number of fmall cryftals, Derbymire cas about the fize of tobacco-feeds, of a pale yellow colour, which one appeared from the fhape of the mafs of them, to have been depofited on the furface of cryftals of carbonate of lime, of the form of Fig. 28. Plate IV. of the Criftallographie of Romé de L’Ifle, The fmallnefs of thefe calamine cryftals, and a want of External cha- fharpnefs rendered it impoffible to determine their form with ers, &c. cetlainty : 78 CHEMICAL ANALYSIS OF SOME CALAMINES¢ certainty; they were evidently, however, rhomboids, whofe facée were very nearly, if not quite, rectangular, and which were in- complete along their fix intermediate edges, apparently hke Fig. 78. Plate IV. of Romé de L’Ifle. 22.1 grs. of thefe cryftals, at a heat of 57° Fahrenheit, dif- placed 5.1 grs. of water, which gives their denfity = 4.333. Heat did not excite any eleétricity in thefe cryftals. b. Before the blowpipe, they grew more yellow and opaque, and fpread flowers on the coal. They diffolved wholly in borax: and microcofmic falt, with effervefcence. ¢. 22.0 grs. during their folution in vitriolic acid, effervefced, and loft 7.8 grs. of carbonic acid = 0.354. This folution was colourlefs, and afforded 26.8 grs. of arid vitriol of zinc, which, rediffolved in water, fhot wholly into clear colourlefs prifms of this falt, Component | d. 9.2 grs. of thefe cryftals, ignited in a covered tobacco- parts carbonic acid and oxide of P'pe, loft 3.2 grs. = 0.3478 ; hence thefe cryftals confift of, zinc. Carbonic acid - - - 0.348 Calx of zinc + ml git - 0.652 Experiments. 1.000. Eleé&trical Calamine. EleGrical ca- = The Abbé Hauy has confidered this kind as differing from lamine from c 2 : ea ree Saw ary Rerbania. the other calamines only in the circumftance of being in diftinét cryftals; but it has already appeared, in the inftance of the Derby thirecalamine, that allcryftals of calamine are not eleétric’ by heat, and hence, that it is not merely to being in this ftate that this fpecies owes the above quality. And the following experiments, on fome cryftals of electric calamine from Reg- bania in Hungary, can leave no doubt of its being a com~ bination of calx of zinc with quartz; fince the quantity of quartz obtained, and the perfe@t regularity and tranfparency of thefe cryftals make it impoffible to fuppofe it a foreign admixture in them. . a. 23.45 grs. of thefe Regbania cayftals, difplaced 6.8 grs. oe diftilled water, from a ftopple-bottle, at the temperature ee ° Fahrenheit; their fpecific gravity is therefore = 3.434. he he form of thele cryftals is reprefented in Figure I, Plate V. where the angle formed by the planes a and c was 90°, that by a and e = 150°, a by b and c = 15%, and that by c and C150": They were not feraiched by a pin; a knife marked them. 3 b. One CHEMICAL ANALYSIS OF SOME CALAMINES. 79 6. One of thefe cryftals, expofed to the flame of the blow- Blowpipe ex pipe, decrepitated and became opaque, and fhone witha green Ponments. light, but feemed totally infufible. ; Borax and microcofmic falt diffolved thefe cryftals, without any effervefcence, producing clearcolourlefs glafles, Carbonate of foda had little if any a€tion on them. c. According to Mr. Pelletier’s experiments * on the cala- mine of Fribourg in Brifgaw, which is undoubtedly of this {pecies, its compofition is, Quartz - - - - - 0.50 Calx of zinc - 2 = - 0.38 Water ~ 8 “ " « Owl? 1.00. The experiments on the Regbania cryftals have had different refults; but, though made on much fmaller quantities, they will perhaps not be found, on repetition, lefs in conformity with nature. 23.45 grs. heated red hot in a covered crucible, decrepitat- ed a little, and became opaque, and loft 1.05 grs. but did not fall to powder or grow friable. It was found, that this matter was not in the leaft deprived of its eleétrical quality by being ignited ; aad hence, while hot, the fragments of thefe decrepi- tated cryftals clung together, and to the crucible. d, 22.2 grs. of thefe decripitated cryftals, = 23.24 grs. of the original cryftals, in a ftate of impalpable powder, being digefted over a fpirit-lamp with diluted vitriolic acid, fhowed no effervefcence ; and, after fome time, the mixture became a jelly. Exhaled to drynefs, and ignited flightly, to expel the fuperfluous vitriolic acid, the mafs weighed 37.5 grs. On extraétion of the faline part by diftilled water, a fine powder remained, which, after ignition, weighed 5.8 grs. and was quartz. The faline folution afforded, on cryftallization, only vitrio] Component parts of eleétri« of zinc. Thefe cryftals therefore confit of, cal calamine. Quartz - - - - 0.250 Calx of zinc - - = - 0.683 Water - - - - - 0.044 O77 Lofs “ - ~ - - 0.023 1.000. * Journal de Phyfique. Tom. XX. p. 414, The 80 It is found in Derby thire. Component parts of fulphate of zince CHEMICAL ANALYSIS OF SOME CALAMINES. The water is moft probably not an effential element of this calamine, or in it in the ftate of, what is improperly called, water of cryftallization, but rather exifts in the cryftals in fluid drops interpofed between their plates, as it often is in cryftals of nitre, of quartz, &c, Its fmall quantity, and the eryftals not falling to powder on its expulfion, but retaining almoft per- fetly their original folidity, and {pathofe appearance in the places of fraéture, and, above all, preferving their eleétrical | quality wholly unimpaired, which would hardly be the cafe after the lofs of a real element of their conftitution, feem to warrant this opinion. If the water is only accidental in this calamine, its compofi- tion, from the above experiments, will be, Quartz. - - - - - 0.261 Calx of zine - - te 0.739 1.000 I have found this fpecies of calamine amongft the produc- tions of Derbyfhire, in fmall brown cryftals, depofited, to- gether with the foregoing {mall cryftals of carbonate of zinc, on cryftals of carbonate of lime. Their form feems, as far as their minutenefs and compreffion together would allow of judging, nearly or quite the fame as that of thofe from Reg~ bania ; and the leaft atom of them immediately evinces its nature, on being heated, by the ftrong eleétricity it acquires. On their folution in acids, they leave quartz. OBSERVATIONS. Chemiftry is yet fo newa fcience, what we know of it bears fo fall a proportion to what we are ignorant of, our know- ledge in every department of it is fo incomplete, fo broken, confifting fo entirely of ifolated points thinly fcattered like lucid fpecks on a vaft field of darknefs, that no refearches can be undertaken without producing fome faéts, leading to fome confequences, which extend beyond the boundaries of their im-— ete objeét. . The foregoing experiments throw light on the proportions in ee its elements exift in vitriol of zinc. 23.0 grs. of the Mendip Hill calamine, produced 29.8 grs. of arid vitriol of zinc. Thefe 23.0 grs. of calamine contained 14.9 grs. of calx CHEMICAL ANALYSIS OF SOME CALAMINES.» oD ealk of zinc; hence, this metallic falt, in an arid ftate, con- fifts of exaétly equal parts of calx of zinc and vitriolic acid. This inference is corroborated by the refults of the other experiments: 68.0 grs. of the Bleyberg calamine, containing 48.6 grs. of calx of zinc, yielded 96.7 grs. of arid vitriol of zinc ; and, in another trial, 20.0 grs. of this ore, containing 14.2 grs. of calx of zinc, produced 28.7 grs. of arid vitriol of zinc. The mean of thefe two cafes, is 62.7 grs. of arid vitriol of zinc, from 31.4 grs. of calx of zinc. In the experiment with the cryftals of carbonate of zinc from Derbythire, 14.35 grs. of calx of zinc furnifhed indeed only 26.8 grs of arid vitriol of zinc; adeficiency of about ~$,5, occa- fioned probably by fome fmall inaccuracy of manipulation. 2. When the fimplicity found in all thofe parts of nature Pofition that the which are fufficiently known to difcover it is confidered, it “eve ciece i p : pounds do not appears improbable that the proximate conftituent parts of greatly exceed bodies fhould be united in them, in the very remote relations to ach other in each other in which analyfes generally indicate them ; and, an oo attention to the fubjeét has led me to the opinion that fuch is in faét not the cafe, but that, on the contrary, they are univer~ fally, as appears here with refpeét to arid vitriol of zinc, frac- tions of the compound of very low denominators. Poflibly in few cafes exceeding five. The fuccefs which has appeared to attend fome attempts to apply this theory, and amongft others, to the compofitions of fome of the fubftances above analyfed, and efpecially to the calamine from Bleyberg, induces me to venture to dwell here a little on this fubje€t, and ftate the compofition of this cala- mine, which refults from the fyftem, as, befides contributing _ perhaps to throw fome light on the true nature of this ore, it may be the means likewife of prefenting the theory under cir- cumftances of agreement with experiment, which, from the furprifing degree of nearnefs, and the trying complexity of the _ cafe, may feem to entitle it to fome attention. From this calamine, containing, according to the refults of Hence the com- _ the experiments on the Mendip Hill kind, too {mall a quantity ee, of carbonic acid to faturate the whole of the calx of zinc init, mine are fup- and from its containing much too large a portion of water to es Geert Th Saar ‘ ged in fubare be in it in the ftate of mere moifture or dampnefs, it feems to dinate com- confift of two matters; carbonic of zinc, and a peculiar com- Pounds. _ pound of zinc and water, which may be named hydrate of zinc. Vor. VI.—Octoser, 1803. G By Elucidations of chemical theory. CHEMICAL ANALYSIS OF SOME CALAMENES, By the-refults of the analyfis of the Mendip-Hill calamine, » corrected by thetheory, carbonate of zinc appears to confift of, Carbonicacid - + - - & : Calx of zinc mal), SNR ae Deduéting from the calx of zinc in the Bleyberg calamine, that portion which correfponds, on thefe principles, to its yield of carbonic acid, the remaining quantity of calx of zinc and water are in fuch proportions as to lead, from the theory, to confider hydrate of zinc as compofed of Calx of zinc - - ~ = 2 Water, or rather ice - e - z And, from thefe refults, correéted by the theory, I confider Bleyberg calamine as confifting of, Carbonic of zinc = aes si attee Hydrate of zinc © - - 3 : s The teft of this hypothefis is in the quantities of the remote elements which analyfis would obtain from a calamine thus compofed, The following table will fhow how very infignificantly the calamine compounded by the theory, would differ in this ree {peét from the calamine of nature. 1000 parts of the compound falt of carbonate and hydrate of zinc confilt of, : Carbonic 400 Carbonate of zinc} acid = ———-= ----- — 133% 400... = ‘~ Calx of 400 x 2 Zing = == 9662 = — 716} Calx of 600% 3 , Hydrate of zinc zinc - = Hike, i hh = 600 4-= - - 4 ’ 600 Ice.) oss ae Ss ee - 156 4 Die ca 1000. Great as is the agreement, between the quantities of the lat column and thofe obtained by the analyfis of the Bleyberg ca- famine, it would be yet more perfeét, probably, had there been, in this inftance, no fources of fallacy but thofe attached j to chemical operations, fuch as errors of weighing, wafte, &c, but 3 CHEMICAL ANALYSIS OF SOME CALAMINESs but the differences which exift are owing, in fome meafure at leaft, to the admixture of carbonate of lime and carbonate of lead, ih the calamine analyfed, and alfo to fome portion of water, which is undoubtedly contained, in the ftate of moifture, in fo porus and bibulous a body. It has alfo appeared, in the experiments on the Mendip Hill calarnine, that acids indicate a greater quantity of carbonic acid than fire does, -225. If we make this deduétion for diffolved water, it reduces the quantity of carbonic acid in the Bleyberg calamine, to 0.1321. If we affume this quantity of carbonic acid as the datum to calculate, on this fyftem, the compofition of the calamine from Bleyberg, we fhall obtain the following refults : Compceund falt, of carbonate of zinc and hydrate of zinc 990.3 Water inthe ftate of moifture - - «© = 25 Carbonate of lime and carbonate of lead + 8 - WV 7 1000.0 It may be thought fome corroboration of the fyftem here offered, that, if we admit the proportions which it indicates, 83 Elucidations of chemical theorye the remote elements of this ore, while they are regular parts . of their immediate produéts, by whofe fubfequent union this ore is engendered, are alfo regular fraétions of the ore itfelf: thus, : The carbonic acid - » - =e The water a = = é =, The calx of zine - ~ - me ES Hereby difplaying that fort of regularity, in every point of view of the objeét, which fo wonderfully charaéterifes the works of nature, when beheld in their true light, If this calamine does confift of carbonate of zinc and hydrate of zinc, in the regular proportions above fuppofed, little doubt can exift of its being a true chemical combination of thefe two taatters, and not merely.a mechanical mixture of them ina pulverulent ftate; and, if fo, we may indulge the hope of fome day meeting with this ore in regular cryftals. If the theory here advanced has any foundation in truth, the difcovery will introduce a degree of rigorous accuracy and certainty into chemiftry, of which this fcience was thought to - be ever incapable, by enabling the chemift, like the geome- trician, to re@tify by calculation the unavoidable errors of his G2 manvwal 84 CHEMICAL ANALYSIS OF SOME-CALAMINES, Elucidations of manual operations, and by authorifing him to eliminate from chemical theorys the effential elements of a compound, thofe produéts of its TEE Se analyfis whofe quantity caynot be reduced to any admiffible proportion. A certain knowledge of the exaé€t proportions of the con- ftituent principles of bodies, may likewife open to our view harmonious analogies between the conftitutions of related objeéts, general laws, &c. which at prefent totally efcape us. In fhort, if it is founded in truth, its enabling the application of mathematics to chemiftry, cannot but be produétive of material refults * 3. By the application of the foregoing theory to the experi- ments on the eleétrical calamine, its elements will appear to be, Quartz - - - SM Calx of zinc - - - - - A {mall quantity of the calamine having (caged! the aétion of the vitriolic acid, and remained undecompofed, will account for the flight excefs in the weight of the quartz. 4, The exhalation of thefe calamines at the blowpipe, and the flowers which they diffufe round them on the coal, are probably not to be attributed to a direé volatilization of them, It is more probable that they are the confequences of the dif- oxidation of the zinc calx, by the coal and the inflammable matter of the flame, its fublimation in a metallic ftate, and in- ftantaneous recalcination. And this alternate reduction and combuftion, may explain the peculiar phofphoric appearance exhibited by calces of zine at the blowpipe. | The apparent fublimation of the common flowers of zinc at the inffant of their produé€tion, though totally unfublimable afterwards, is certainly likewife but a deceptious appearance. The reguline zinc, vaporifed by the heat, rifes ‘from the crucible as a metallic gas, and is, while in this ftate, convert- ed toacalx. The flame which attends the procefs is a proof of it; for flame is a mafs of vapour, ignited by the produétion of fire within itfelf. The fibrous form of the flowers of zinc, is owing toa oo of the calx while in mechanical f~ ple pls * It may be pr oper to fay, that the experiments have been ftated precifely as they turned out, and have not been in the Jeafl degree bent to the fyftem. penfion CHEMICAL ANALYSIS OF SOME CALAMINES. 85 penfion in the air like that which takes place with camphor’ Elucidations of when, after having been fome time inflamed, it is blown out. chemical theorys A moment’s refleGtion muft evince, how injudicious is the common opinion, of cryftallization requiring a ftate of folution in the matter ; fince it muft be evident, that while folution fub- fifts, as long asa quantity of fluid admitting of it is prefent, no cryftallization can take place. The only requifite for this opera- tion, is a freedom of motion in the maffes which tend to unite, which allows them to yield to the impulfe which propels them together, and to obey that fort of polarity which occafions them to prefent toeach other the parts adapted to mutual union. No fiate fo completely affords thefe conditions as that of me- chanical fufpenfion in a fluid whofe denfity is fo great, rela- tively to their fize, as to oppofe fuch refiftance to their defcent in it as to occafion their mutual attraction to become a power fuperior to their force of gravitation. It is in thefe circumftances that the atoms of matters find themfelves, when, on the fepa- ration from them of the portion of fluid by which they were diffolved, they are abandoned in a difengaged ftate in the bofom of a folution; and hence it isin faturated folutions fuf- taining evaporation, or equivalent cooling, and free from any perturbing motion, that regular cryftallization is ufaally effefted. ; But thofe who are familiar with chemical operations, know the fort of agglutination which happens between the particles of fubfided very fine precipitates: occafioning them, on a fecond diffufion through the fluid, to fettle again much more quickly than before, and which is certainly a cryftallization, but under circumftances very unfavourable to its perfeét per- formance. 5. No calamine has yet occurred to me which was a real, uncombined, calx of zinc. Iffuch, as a native produé, fhould ever_be met with in any of the ftill unexplored parts of the earth, or exift amongft the unfcrutinized poffeffions of any cabinet, it will eafily be known, by producing a quantity of arid vitriol of zinc exa@ly double its own weight; while the hydrate of zinc, fhould it be found fingle, or uncombined with the car- bonate, will yield, it is evident, 1.5 its weight of this arid falt. TABLE 86 RADII, OF WHEELS. VI. Table of the Radii of Wheels, from Ten to Three Hundred Te eeth,: the Pitch* being Tuo Inches. By Mr. B. Donxin, Millwright, Dartford, Kent t. Table of the sages ti No. | Radius i radii of wheels of ih No. | Radius. No. | Radius. Teeth} Inches. 10 3,236 42}. 13,382. _ TA | 23,562 1] 3,549 43 | 13,700 75 | 23,880 12| 3,864 44} 14,018 76 | 24,198 13 | 4,179 45 | 14,336 77 | 24,517 14] 4,494 46] 14,654 78 | 24,835 15 4,810 47 | 14,972 79.\) 25,153 16 | 5,126 48 | 15,290 80 | 25,471 17 | ° 5,442 49 | 15,608 81 | 25,790 18 5,759 50 | 15,926 82 | 26,108 19 | 6,076 51} 16,244 83 | 26,426 20 | 6,392 521 16,562 84 | 26,744 21 6,710 53 | 16,880 85 | 27,063 Pood Bul27, 54 | 17,198 86 | 27,381 93 | 7,344 55.4 by yo he 87 | 27,699 24 | 7,661 56 | 17,835 88 | 28,017 25 7,979 57d: 18,053 89 | 28,336 26 8,296 58 | 18,471 90 | 28,654 27 | 8,614 59 | 18,789 91 | 28,972 28 8,931 60 | 19,107 92 | 29,290 29 | 9,249 61 | 19,425 93 | 29,608 30 | 9,567 62 | .19,744 94 | 29,927 31 | 9,885 | 63 | 20,062 95 | 30,245 32 | 10,202 64 | 20,380 96.| 30,563 } 33 | 10,520 65 | 20,698 97 | 30,881 | 34 | 10,838 66 | 21,016 98 | 31,200 35 | 11,156 67 | 21,335 99 | 31,518 36 | 11,474 68 | 21,653 100 |- 31,836 37 "| 11,792 69 | 21,971 — F101 | 32;155 38 | 12,110 70 | 22,289 102 | 32,473 39 | 12,428 71 | 22,607 103 | 32,791 40 | 12,746 72 | 22,926 104 | 33,109 4} 13,064 73 | 23,244 105 | 33,427 op eS ge a ee 5 ea * By the pitch is underftood the diftance between the centers of two Contiguous teeth; and by the radius is underftood the diftance between the center of the wheel and the center of each tooth. t Communicated by the author. : . No Radius. 34,064 345382 34,700 35,018 OIF aT 35,655 35,974 536,292 36,929 37,247 37,565 37,883 38,202 38,520 38,838 39,156 - 39,475 39,793 40,111 40,429 40,748 41,066 41,384 41,703 | 42,021 42,539 42,657 42,976 43,294 43,612 43,931 44,249 44,567 44,885 45,204 45,522 45,840 46,158 46,477 46,795 47,113 47,432 47,750 | 33,746 36,6) 1. RADIL OF WHEELS. Radius. 48,068 48,387 48,705 49,023 49,341 4.9,660 49,978 50,296 50,615 50,933 51,251 51,569 51,888 52,206 52,524 52,843 53,161 53,479 53,798 54,116 54,434 54,752 55,071 55,389 55,707 56,026 56,344 56,662 56,980 57,299 57,617 57,935 58,253 58,572 58,890 59,209 59,527 59,845 60,163 60,482 60,800 61,118 61,436 61,755 62,073 Radi us, 62,392 62,710 63,028 . 63,346 63,665 63,983 64,301 64,620 64,938 65,256 65,57 4 65,893 66,211 66,529 66,848 67,166 67,484 67,803 68,1211 68,439 68,757 ' 69,075 69,394 69,712 70,031 70,349 ° 70,667 70,985 — 71,304 71,622 71,941 72,258 72,577 72,395 73,214 73,532 73,850 74,168 74,487 74,805 75,123 75,441 75,760 76,078 16,397 87 Table of the radii of wheels, 88 Table of the radii of wheels. -_ RADII OF WHEELS. Nc No. Radius, No. Radius. No. Radius. 241 | 76,715 261 | $3,081 281 | 89,447 242 | 77,033 262 | 83,399 | -| 282] 89,765 243 | 77,351 263 | 83,717 283 | 90,084 244 | 77,670 264 | 84,036 284 | 90,402 245 | 77,988 265 | 84,354 285 | 90,720 246 | 78,306 266 | 84,673 | ’ | 286 | 915038 247 | 78,625 267 | 84,991 287 | 91,357 248 | 78,943 268 | $5,309 288 | 91,675 249 | 79,261 269 | 85,627 289 | 91,993 250 | 79,580 270 | 85,946 290 | 92,312 251 | 79,898 271 | 86,264 291 | 92,630 252 | 80,216 272 | 86,582 292 | 92,948 253 | 80,534 273 | 86,900 293 | 93,267 254 | 80,853 274| 87,219 294 | 93,585 255 | 81,171 275 | 87,537 255 | 93,903 256 | 81,489 276 | 87,855 | 296 | 94,229 257 | 81,808 277 | 88,174 297 | 94,540 258 | 82,126 278 | 88,492 298 | 94,858 259 | 82,444 279 | 88,810 299 | 95,177 260 | 82,763 280 | 89,129 300 | 95,495 | N. B. When the pitch is different from two inches, the radius of a wheel of any number of teeth, from 10 to 300 may be found from this table, by the Rule of Three; for as two inches (the pitch in the table) is to any radius in the table, fo is any given pitch to the radius required. For Example ; let it be required to find the radius of a wheel of 100 teeth, when the pitch is 1} inches. The radius of a wheel of 100 teeth is, in the table, 31,836 inches. Accord- ingly we have 2 : 31,836 : : 1,25, to the number of inches in the radius required ; which will be found 19,897 as by the Operation annexed. 2 B1;836-09 1,25 1525 159180 | 63672 31836 2) 39,79500 19,8975 ‘ VII. Account n PYROMETER OF PLATINAs 89 sind Ate Account of the Pyrometer of Platina. By Citizen GuyTon.* Cinzen GUYTON prefented an inftrument to the irieken ail for ting of the French National Inftitute of the 26th Floreal laft, Gifting of pecranik intended to meafure the highéft degrees of heat of our furnaces. of platina moved It confifts of a rod or plate of platina placed horizontally in i ish a groove formed in a cake of hardened white clay. This plate fame metal; the is fupported at one of its extremities on the part of the mafs vont ing. 10 which terminates. the groove; the other end preffes againft a ce baked clay. bended lever, whofe longeft arm forms an index toa graduated sl is resin by arc; fo that the change of poiition of this index indicates the ie Bei | expanfion produced on the plate of metal by the heat. pottery and pla The cake of clay having been highly baked, leaves no caufe Defeription. to apprehend any contraction; and the expanfion which may take place during the ignition will only affeét the very fmall diftance between the axis of motion of the index and the point of contaét of the plate, that is to fay, in fuch a manner as ra- ther to diminith the effeé& than to increafe it. All the parts of this inftrament being of platina, neither fu- fion nor oxidation are to be apprehended. With refpe& to its dimenfions, the author conceives that in Dimenfions. order to render the ufe of it commodious and accurate, they ' fhould be reduced to fuch as may be neceffary to obtain fenfible variations ; it will then be rendered commodious by the facility with which it may be placed under a muffle or an inverted erucible, &c. and accurate, becaufe the probabilities of any accidental inequalities of the heat will be diminifhed, which it is impoffible to avoid to a certain extent, even in the midft of a large mafs of fire. : The variations will be fafficiently perceptible, if we can not Degree of accu- only eftimate, but correétly determine expanfions of the 200th ™°Y: part of a millimetre (about the 5000th part of an inch,) thefe the author obtains by the proportions of the inftrument which he has himfelf adopted. The rod or plate of expanfion is 45 millimetres (one inch Dimenfions of and three quarters) in‘length, 5 in width (one fifth of an inch) "© Parts. and 2 in thicknefs (one thirteenth of an inch.) * Annales de Chimie, No. 138. XLVI. 276. The 90 PYROMETER OF PLATINA. The arm of the bended lever, which prefies againft the end of this rod, is 25 millimetres in length; (rather 24, or about one ninth of aninch) and the arm at right angles to it, or the index, which traverfes on the graduated arc, is 50 millimetres in length (one inch and eight tenths) or twenty times the length of the other. The fpace traverfed by the difplacing of the © fmall arm will be thus encreafed in the proportion of t to 20. As the long arm or index carries a nonius which divides each degree on the graduated arc into ien parts, we can dif- tin@tly obferve the 200th of one of thofe meafures (referred to the bar itfelf.) , Laftly, As the decimal divifion of an are of a circle of 50 millimetres radius, gives only 7.8538 deci-millimetres for one of its degrees, it is evident then that we may meafure an ex- panfion of 0.078538 deci-millimetres, or of the 5730th part of the length of the radius. In order to prevent the pofition of the index from being . changed in removing the inftrument from the furnace, a plate of platina is fixed fo as to form a fpring againft its extremity. The author has commenced a feries of éxperiments to de- termine the range of this pyrometer, to compare.it-with the pyrometric pieces of Wedgewood, and fo to fhew the degree of confidence it merits, the methods of ufing, and the cafes in which it may be ufefully employed in philofophical refearches and in the arts. —a Vil. Lester from Mr. Ezekiel Walker on the Proportion of Light afforded by Candles of different Dimenfions. To Mr. NICHOLSON, SIR, Obfervations on Your correfpondent, who has made fome remarks on my be iy tothe experiments on candles, does not feem to have fufficiently confidered his fubjeét; for had he paid attention to my paper on page 40 of the fourth volume of your Journal, he could not have advanced that ‘ Though Mr. Walker afferts with con- fiderable decifion, that the light afforded by candles, is pro- portioned to the quantity of material confumed, yet he has not given PROPORTION OF LIGHT AFFORDED. BY CANDLES. Ol given the detail of his experiments, but feems in fome mea- fure to have difcovered this refult by argument, from the fup- pofed nature of the fubjeé.” * In the table in my paper above mentioned, the laft cobain Obfervations of contains the diftances of the candles from the wall, when the i oy fhadows were equal; and the fourth column contains the the weights cone weights of thofe candles confumed ina given time, and thefe aanee are all the data required for making the calculations, to fhow whether my deduction is true or falfe. The mode of calcu- lating feemed to me, at the time I wrote that paper, too eafy to need any illuftration, but as I now ftand charged by your correfpondent, of having deduced a general law from doubtful principles, a further explanation becomes neceffary. To inveftigate rules for this purpofe, 1. Let M reprefent the Inveftigation of mould Bandle, a its diftance from the wall, on which the fha- at ae val dows were compared, x its quantity of matter confumed ina re given time, (¢) and Q the quantity of light emitted by M in the fame time: 2. Let m reprefent any other candle, b its dif- ‘tance from the fame wall, and y its quantity of matter con- fumed, in the time ¢. Then as the intenfities of light are direéily as the fquares of the diftances of the two candles from the wall, we have, as 2 ~a*:Q:: db: axes the quantity of light, emitted by m inthe time, | _ Then let us fuppofe that the quantities of light are direétly as the quantities of matter confumed in the time ¢, and we eaves; As 2 > Qs: y 3 —_ = the quantity of light emitted by m in fe time, by hypothefis. ee Now, when —— (ied...) is: = = ~ = (Theo. 2.) the quantities of light of M and m are dire as their quan- . tities of matter dawhithied in any given time, By thefe rules, the calculations contained in the following table, were made from the experiments mentioned at the be- ginning of this paper. * See Philofophical Journal, Vou, V. page 219% CY PROPORTION OF LIGHT AFFORDED BY CANDLES, Light | Light | 2dRule by | by (differsfrom Rule I. |Rule 1]. | the rf. No of ex- periments. 1 {No. 1. compd. with the mould | 1.000} 1.000} .000 2 |No. 1. compd. with do. 1.000 | 1.000 .000 3 |No.1.compd. with do, 1.000 {1.015 | + .015 3 |No. 3. compd. with do. 1,196 | 1.125 | — .07] 4 |No, 4. compd, with do. 1,196 | 1.226 | + .030 The mean error of the 2d Rule — .005 As the mean refult given by the 2d rule, differs only 1 in 200 from the 1{t, which is univerfally received as true, the 2d rule appears fufficiently exaét for many praétical purpofes, where the properties of that light is concerned, which is produced by candles, EZEKIEL WALKER. Lynn Regis, 20th Sept. 1803. Whether the P. 8S. As to your correfpondent’s experiment, it does not experiments of a annear fo correét to me, as it appears to himfelf; for every one correfpondent be : a eccurate, knows, that one end of a mould candle is thicker than the other, therefore if that gentleman made his experiment with the {mall end of his candle, he has eftimated the quantity of light pro- duced by a pound, too little; and if he made his experiment with the large end, his eftimation is too great; and moreover, it may be doubted, whether the 4, part of a pound of candles, can be fo exaétly afcertained by meafuring as by weighing, even if the candles were perfeét cylnders. a IX. On the Compounds of Sulphur and Ovygen. By Tuomas — ‘Tuomson, M. D. Leéturer on-Chemiftry in Eien From the Author. Three known if compounds of Tis at prefent the opinion of Chemifts that fulphur is capa- cra sagetienortmggl combining with three dofes of oxygen, and of forming — ygen, 1. oxide, 2. acids. three diftinét compounds, namely, 1.,Oxide of Sulphur. 2 Sulphurous Acid. 3. Sulphuric Acid. i The ON THE COMPOUNDS OF SULPHUR AND OXYGEN. , 93 The firft of thefe is fuppofed to contain a minimum, the third ’ amaximum of oxygen. “Of thefe three the conftituents of the laft only have been afcertained with precifion. It will be proper to begin with it, as the knowledge of its compofition _ may be of fervice in afcertaining the conftituents of the reft. I. Of Sulphuric Acid. This acid has been lately analyfed with precifion by Sulphuric acid, Thenard and Chenevix. I have repeated their experiments a vaete (ee with care, and have obtained for the mean refult 39 per cent. oxygen. of oxygen, which is only one half per cent. greater than the refult obtained by Mr. Chenevix. This difference in the pre- fent ftate of analyfis may be accounted altogether infignificant. I fhall confider fulphuric acid, then, as compofed of F 61 fulphur 39 oxygen 100 II. Of Sulphurous Acid. Moft of the properties of this Acid have been long known Sulphurous acid. _tochemifts; but no experiments have been made to afcertain the proportion of its component parts. Before I proceed to relate the refult of mine, it may be worth while to defcribe a few of the properties of Sulphurous Acid, which have not hi- | therto been ftated with precifion. ¢ 1. Fifty-three meafures of fulphurous acid gas were intro- Water at 60° ab- duced into'a graduated tube ftanding over mercury, and one Reged meafure of water was thrown up. In five minutes 20 mea-its piehtoe Ol. fures of gas were abforbed, and in 24 hours the abforption Phurous canuP amounted to 33 meafures. No farther abforption took place in three days more ;_ but on introducing the tube into water, the whole gas difappeared, except a {mall globule, which did not exceed 1-10th ofa meafure. During this experiment the thermometer at the time of obfervation deviated very little from 61°, and the barometer ofcillated from 29.55 to 29.77. Water then, at the temperature of 61°, abforbs 33 times its bulk of this gas. Now, if with Lavofier, we fuppofe a cubic inch of gas to weigh 0.63 grs. a cubic inch of water will ab- forb 19.79 grains of fulphurous acid, and ¢° parts of water will abforb 8.21 parts by weight. "2, A current Od ON THE COMPOUNDS OF SULPHUR AND OXYGEN. The impregnat- 2. A current of fulphurous acid gas was paffed through a nate 5 Sy large quantity of water till the liquid refufed to abforb any gratity ve pas more. The'tafte of the water thus faturated, was{intenfely ci a acid and fulphureous, and its odour exceflively ftrong. The Sere aot fpeenie gravity at the temperature 68° was 1.0513; the heat of the hand was fufficient to occafion an extrication of gas. Whien moderately heated, it frothed violently, and exhaled the denfe blue f{moke which ufually indicates the prefence of fulphurous acid. When boiled down in a retort to half its bulk, it loft its fmell, but ftill continued ri ap acid. Hence it obvioufly contained fulphuric acid. Analyfis of ful- - 3. In analyfing the different fulphites, I have not found Pate barytes an{wer fo well as I was led to expeét from the experi- phurous acid ments of Fourcroy and Vauquelin; the folubility of fulphite. paras oF iia of barytes in water is fo confiderable, that precifion by means phuric acid. of it is fcarcely to be looked for. But nitrate of lead yields’ with the alkaline and earthy fulphites a white infoluble powder of fulphite of lead, which may be dried in the temperature of 800° without decompofition, and is then compofed of about 25 fulphurouws acid. ‘a 75 yellow oxide of lead. 100 One hundred parts of the above liquid fulphurows acid yielded, with nitrate of lead, a precipitate indicating the pre-- fence of 6.15 parts of fulphurous acid. Another hundred parts, boiled down to one half in a retort, yielded, with muriate of barytes, a precipitate indicating the prefence of 0.34 ful-.. phuric acid. Therefore, 100 parts of my liquid fulphurous acid contained about 5.81 fulphurous acid, 0.34 fulphuric acid, 6.15. So that the fulphuric acid amounts nearly to 4 of the ful- phurous. The prefence of this acid is a proof of an affinity between fulphurous acid gas and fulphuric acid ; for the gas. was pafled through an intermediate veffel before it reached the water. This contamina~ 4, The proportion of\ acid combined with water in the li- ae ga nase quid fulphurous aaid was rather lefs than 7 ; yet, when water lefs capable of js plunged into a large column of gas, we have feen that it abforbing ful- abforbs: _phurous gas. ON THE COMPOUNDS OF SULPHUR AND OXYGEN, 95 abforbs rather more than eight parts of it by weight. Perhaps this difference was owing to the prefence of the fulphuric acid in the liquid. For water, flightly acidulated with fulphuric acid, abforbs a {maller proportion of gas, than pure water. 5. After trying various experiments, in order to afcertain Analyfis of fuls the conftituents of fulphurous acid, I found the following Phurous acid, method moft to be depended on. Sulphite of potafh was obtained by Berthollet’s method. Sulphite of pote It isa fine white falt, the properties of which have been Pe gtr by aiiee fully detailed by Fourcroy and Vauquelin, though they haveheat: by igni- negleéted to analy(e it. tion it lofes 22.3, 5 f % é _and fulphuric When this falt is expofed for a few minutes to a heat ofacid with the ale 300°, it lofes 3.3 per cent. of its weight; and fuffers no ad-ali areleft. ditional lofs, though the heat be continued for an ‘hour. When heated to rednefs in a platinum crucible, it decrepi- tates, becomes of an opake white, a blue flame iffues from below the lid, and, on taking off the cover at that inftant, the falt may be obferved of a glowing red heat in the middle. When this glow difappears, tie falt willbe found to have fuf- tained a lofs of 22.3. per cent. and it lofes no more, though melted, and kept half an hour in fufion. On evolving, it fplits _ into the fine thin tranfparent plates, which diftinguih fulphate of potath in the fame circumftances. When this refidue is dif- -folved in water, and treated with muriate of barytes, this q precipitate of fulphate of barytes obtained, when dried and heated to rednefs, weighs 95.5, indicating the prefence of 22,92 fulphuric acid, Suppofing with M. Chenevix, that _ fulphate of barytes contains 24 per cent. of fulphuric acid 3 _ hence it follows that fulphate of potath is compofed of 22.30 volatile matter 22.25 fulphuric acid 55.45 potafh ed 100.00 When 100 grains of fulphate of potath were expofed to the The volatile heat of a lamp in a retort with a very long beak, fitted to a tis fulphu- rous gas, with © mercurial air holder, they decrepitated and affumed the ap-fome fulphur "pearance of an opake white powder: 18 cubic inches of gas pee hae Wee were extricated, and fulphur, with a little water, was volati- 4 lized into the beak of the retort; the gas was abforbed by | water, and had the ufual {mell of fulphurous acid: the retort had 96 Component parts of fulphite of potafh. Explanation of the aétion of heat on fulphite of potafh. ON THE COMPOUNDS OF SULPHUR AND OXYGEN. had loft 15.2 grains of weight. The fulphur being carefully colleéted, was found to weigh 5.1 grains. When burnt, it left 0.1 of refiduum, which feemed to be fulphurate of iron, for it gave a yellow colour to muriatic acid ;* the water vola-. tilized could not be weighed, but I eftimate it at 2 grains. The experiment fhews us what the volatile matter is which is drawn off when fulphate of potafh is heated to rednefs. It is compofed of 15.2 fulphurous acid 5.1 fulpbur 2.0 water 2250 The falt which remained in the retort being diffolved, and | treated with muriate of barytes, gave a precipitate which in- dicated the prefence of 23.2 of fulphuric acid. Hence ful- phate of potath is compofed of — 23.2 fulphuric acid 15.2 fulphurous acid 5.1 fulphur 54.5 potahh 2.0 water 100.0 But it is obvious that, before the application of heat, the firft three conftituents together conftituted fulphurous acid. Hence fulphite of potath is compofed of 43.5 fulphurous acid 54.5 potafh : 2.0 water 100.0 This analyfis enables us to trace the changes produced upon fulphite of potafh by heat. A temperature of 300° feparates the water and a {mall portion of fulphurous acid, which feems more loofely combined; for the falt, in confequence, lofes its fmell; an increafe of heat occafions a feparation of a portion of the acid, unaltered ; the remainder divides itfelf into two parts, namely, fulphuric acid, which remains com- bined with the potafh, and fulphur, which fublimes. Hence * I have never yet burned fulphur, without obferving traces of a fimilar refiduum. 4 we | : ON THE COMPOUNDS OF SULPHUR AND OXYGEN. 97 we learn, that fulphurous acid is compofed of 23.2 fulphuric acid, and 5.1 fulphur, which gives us 82 fulphuric acid 18 fulphur ‘ 100 But 100 parts of fulphuric acid contain 39 of oxygen; there- fore 82 contain nearly 32, Hence fulphurous acid is com- pofed of 68 fulphur 32 oxygen - 100 Fourcroy affirms, that fulphurous acid contains only about 15 per cent. of oxygen, which is lefs than one half of the refult juft given. But he quotes no experiment in proof of his affer- tion. Inall probability it was a mere guefs. 6. The phenomena which attend the acidification of ful-Sulphurous acid phur and the decompofition of falphurous acid, render it pro ee ee bable that fulphurous acid is rather a compound of fulphuriced with fulphue acid and fulphur, than of fulphur and oxygen. ribet Sulphur and fulphuric acid combine with great facility. For if we form them into a probe, a very tne tleses heat is fufficient to convert the whole into fulphurous acid gas. Whenever fulphur is acidified, a portion of fulphuric acid always makes its appearance in whatever way the procefs is conduéted. Such at leaft has been the conftant refult of my experiments, When fulphur is expofed to the heat of an Argand lamp _ in aretort conneéted with a mercurial air holder, it melts and fublimes at firft rapidly, but much more flowly, when the pro- cefs has continued for fome time. Ina retort, whofe capa city was 63 cubic inches, four hours elapfed before 3 oz, of fulphur was fublimed into its neck. A confiderable quantity of air was driven over; but on allowing the veffels to cool, the whole returned again, except 3 cubic inches. So that, by ‘the operation, the air in the retort had increafed about gothpart. It fmelt very pungently of fulphurous acid. When agitated in water, a {mall portion of it difappeared. The _ water did not acquire a perceptible tafte, but it precipitated Muriate of barytes even after being boiled for fome time. A portion of this air, after being well wafhed, was left in con- _ taét with a flick of phofphorus over water. Its bulk was di- Vor. VIL—Ocroser, 1803. H minifhed O§ ON THE COMPOUNDS OF SULPHUR AND OXYGEN. minifhed 17 percent. Hence it had loft 5 per cent. of oxy- gen by the aétion of the hot fulphur on it. Here we fee the fource of the acidification of the fulphur during its fublimation. From this experiment we are authorized to conclude that both fulphuric and fulphurous acids may be formed merely by heating fulphur in comimon air, without any fenfible com- buftion. Sulphur, when- Sulphuric acid feems to be formed whenever fulphur is a nary aaa fublimed. For every fpecimen of flowers of fulphur which I have had an opportunity of examining, contained that acid. If common flowers of fulphur be boiled in water, the li- quid always precipilates muriate of barytes. But flowers of fulphur, when once they have been well wafhed and dried, communicate no fuch property to water. If we now fublime thefe very flowers a fecond time, water in which they are boiled, precipitates muriate of barytes, as at firit. Combutition of —§ Whena red hot glafs capfule is rapidly placed ona pedeftal of fulphur under 2 fonding water fulphur thrown into it, and a glafs jar fuddenly gar over water. te) y, oe 5 / put over it, the combuftion of the {ulphur continues for a con- fiderable time ; denfe bluifh-white fumes fill the jar, and at laft conceal the flame completely. The fmoke foon fubfides when the combuftion is over, and the water rifes flowly in the jar. . By this procefs, the air in the jar lofes.uniformly 8 per cent. of oxygen; it retains the fmell of fulphurous acid, even though allowed to remain over water for a week. But the fmell difappears in an inflant, if the air be paffed through water. A portion of the water over which the jar ftood, being treat- ed with muriate of barytes, yielded a precipitate which weighed 8. An equal portion of the fame water evaporated to one-fourth, yielded a precipitate which weighed 7. A@ion of acids 7, The ation of the more powerful acids upon the ful- on the fulphitess Shites deferves attention, becaufe it ferves to illuftrate the na- ture of fulphurous acid. ‘This aétion has been defcribed with confiderable minutenefs by Fourcroy and Vauquelin ; but as the refult of my experiments differs a little from theirs, a few obfervations may not be unacceptable to the chemical reader, Yo prevent tedioufnefs, I fhall confine my remarks to fulphite of potath, Aétion of ful- | When fulphite of potafh is thrown into concentrated ful- bikie al ed phuric acid, a confiderable heat is evolved, a violent effer- ath. velcence takes place, and the falt lofes 48 per cent. of ils 4 weight. ON THE COMPOUNDS OF SULPHUR AND OXYGEN, weight. The heat of boiling water renews the effervefcence, _ and occafions a lofs of weight, amounting to 2 per cent. more. So that fulphite of potafh, when treated with fulphuric acid, lofes uniformly the half of its weight. Yet it contains only 43.5 per cent. of fulphurous acid. The additional 6.5 parts may be afcribed perhaps to the efcape of fulphuric acid along with the gas ; for it can fcarcely be doubted that there is an affinity between them, When the fulphuric acid folution is fet afide, brilliant plates of fuper-fulphate of potafh foon make their appearance in it. ~ When fulphite of potafh is thrown into muriatic acid, a violent effervefcence enfues, but no increafe of temperature ; and the falt lofes 34 per cent. ofits weight. The heat of boil- ing water renews the effervefcence, and occafions a farther lofs of 16 per cent. making the whole lofs amount to 50, as in fulphuric acid. From this experiment we fee that muriatic acid does not expel the whole of fulphurous acid, unlefs affift- ed by heat: and inthat cafe, a portion of the muriatic acid is driven off at the fame time with the fulphurous. When the muriatic acid folution is fet afide, beautiful arborefcent cry{- tals of muriate of potafh make their appearance in it. Muriatic acid and fulphite of aih. I diffolved 500 parts of fulphite of potafh in water, and Oxy muziatic putting the folution in a Woulfe’s bottle, caufed a current of oxy muriatic acid gas to pals through it ; the gas paffed after- wards through a fecond bottle of water conneéted to the firft by a bent glafs tube. After the procefs the bottles were fet ' afide, till the green colour, occafioned by the oxy-muriatic acid, difappeared, and the fetid animal odour which ufually fucceeds that colour, was become perceptible. From the firft bottle I obtained, by means of muriate of barytes, a pre- cipitate whch weighed 777 parts, indicating the prefence of 37.3 per cent. of fulphuric acid. Butas the fulphurous acid originally prefent amounted to 43.5 per cent. had it been wholly converted into fulphuric acid, not lefs than 48.5 per cent. of fulphuric acid would have been obtained, there was a lofs then of 11.2 per cent. of courfe, 10.5 parts of fulphurous acid muft have been diffipated by the aétion of the oxy mu- riatic acid. Accordingly the liquid in the fecond phial gave an abundant precipitate with muriate of barytes: and this “8 contrary to what I expected, confifted chiefly of H 2 {ulphite gas and fulphite of potafhe 100 ON THE COMPOUNDS OF SULPHUR AND OXYGEN. fulphite of barytes; for the greater part of it was foluble in fulphurous acid. Nitric acid and When fulphite of potafh is thrown into concentrated nitric fulphite of pot- ath. Compofition of fulphite of pot- afh. acid, a violent effervefcence takes place, and much heat is evolved, the lofs of weight is 44.5; the liquid treated with nitrate of barytes, gives a precipitate, which indicates the pre- fence of 39.6 of fulphuric acid. Hence we fee that the lofs of weight during the effervefcence was owing chiefly to the efcape of nitrous gas. When the acid is diluted, the effervefcence is violent, but no heat is evolved, and the {mell of fulphurous acid gas mak- ing its efcape is very perceptible. The lofs of weight is only | 12 per cent. the refiduum, treated with nitrate of barytes, gave a precipitate indicating the prefence of 43.2 per cent. of ful- phuric acid. Here we fee that moft of the lofs of weight was owing to the efcape of fulphurous acid: yet the greater part was converted into fulphuric acid. 8. During the courfe of thefe experiments I had occafion to examine the compofition of fulphate of potafh ; and as my re- fults differ a little from thofe ftated by others, it will be pro- per to notice fome of them in this place, When fulphite of potafh is heated to rednefs in a pla- tinum crucible, the refiduum pofleffes the properties of fulphate of potafh.. It may be fufed without any lofs of weight, and when diffolved and cryftallized again, we obtain the fame falt as at firft: 100 parts of this falt precipitated by muriate of ~ barytes, yields a precipitate which, after being heated to red- nefs, weighs, at a medium, 96 parts, indicating about 23 per cent. of fulphuric acid. Hence this fulphate is compofed of 23 acid 67 potafh 100 When fulphuric acid is fuperfaturated by means of carbonate of potafh, we obtain by evaporation the common fulphate of potath of chemifts: the fame falt feparates in cryftals during the purification of the potafh of commerce. When the falt is reddened in a platinum crucible, it lofes 1.4 per cent. of its weight, and no more, though it be kept in fufion. Diffolved in water, and treated with muriate of barytes, it yields a pre- cipitate which weighs 128.5 ; the mean of three experiments differing Pid ON THE COMPOUNDS OF SULPHUR AND OXYGEN, JO] differing from each other not more than 3.5 per cent.* Hence it contains 30,84 fulphuric aehd, This fulphate, then, is compofed of 30.84 acid 67.76 potath 1.40 water 100.00 When fulphite of potath is left for fome months expofed to the air, and then heated to rednefs, it yields with muriate of barytes a precipitate indicating about 38 per cent. of ful- phuric acid. The fuperfulphate of potath lofes 26 per cent. ina red heat, and the remaining 74 parts diffolved in water, and treated with muriate of barytes, yield a precipitate indicating the prefence of 30.4 {ulphuric acid, whereas 100 parts of the fuperfulphate diffolved in water, without being previoufly heated, yield, with muriate of barytes, a precipitate indicat- ing the prefence of 38.4 fulpburic acid. Hence it follows that the falt is compofed of 38.4 acid 43.6 alkali 18.0 water 100.0; or, abftraéting the water, of 46.4 acid ° 53.6 alkali 100.0 III. Oxide of Sulphur. Sulphur ufuafly occurs in one or other of three ftates ; External charace namely, 1. A whitifh powder, formerly diftinguiflied by the ters of fulphur. name of lac fulphuris. 2. In rolls or flowers of a greenifh yellow colour. This‘is the fulphur of commerce.. 3. In the ftate of a reddifh yellow, pitchy fubftance. This is commonly employed for forming the cafts of medals, &c. known by the name of fulphurs. * Mr. Vauquelin affirms, in his Differtation on the Potath of Commerce, that this falt yields with muriate of barytes a precipi- tate amounting to 22°, the weight of the falt. My experiment differs very much from this ftatement. tee ~ 102 ON THE COMPOUNDS OF SULPHUR AND OXYGEN. Lac fulpburis, or 1 It is well known that fulphur, when firft obtained by white fulphor, is precipitation from any liquid, is always of a white colour, a Slow fal, Which gradually changes to greenifh yellow when the ful- phur is the pure. phur is expofed to the open air. If this white powder, or lac Sulphuris, as it is called, be expofed to a low heat in a retort, it foon acquires the colour of common fulphur ; and, at the fame time, a quantity of water is depofited in the beak of the retort. On the other hand, when a little water is dropt into melted fulphur, the portion in contaét with the water imme- diately affumes the white colour of lac fulphuris. If common fulphur be fublimed into a veffel filled with the vapour of water, we obtain lac fulphuris of the ufual whitenefs, inftead of the ufual flowers of fulphur, Thefe faéts prove that lac ful- phuris is a. compound of fulphur and water. Hence we may conclude that greenifh yellow is the natural colour of fulphur, Whitenefs indicates the prefence of water. Sulphur render- 2, It has been long known, that when a confiderable quan- priest tity of fulphur is kept melted for fome time in an open veffel, by fufion. it becomes vifcid, changes its colour to a dark violet, and ac- quires a kind of pitchy appearance. The nature of this change has not hitherto been examined by chemifts. Fourcroy, in- deed, affirms, that the fulphur, in this cafe, is in the ftate of an oxide. But the affertion does not feem to have been the refult of any pofitive experiment. Doesnotfueceed J have never been able to produce this change in the ap- in a fhallow vef- Soar : : fel. pearance of fulphur by heating it in a flat difh, where nothing impedes the volatilization, though I have kept it melted in a glafs capfule on fand, heated to 250°, for ten hours toge- ther. But the change takes place in a fhort time, when a con- fiderable quantity of fulphur is kept melted in a crucible; and the greater the quantity employed, the fooner the change is produced, and the more complete it is. Thfs fuppofed When fulphur, thus converted into a fuppofed oxide, is oxide is of a vio~ 5 : : 5 let colour; is foft M¢Wly prepared, its colour is a dark violet, with the metallic if pouredinto luftre ; not very unlike newly-melted muriate of filver, when pag siviaetirans feen by reflected light. If it be thrown fuddenly, while in phur; and tough. fufion, into water, it continues foft for a confiderable time. and, as it hardens, the colour changes from purple to reddith yellow. When broken, it exhibits a fibrous fraéture, com- pofed of fmall prifmatic cryftals: Its fpecific gravity was 2.325. It was very tough, refifting, with a good deal of ob. 4 ftinacy, ~ OF THE COMPOUNDS OF SULPHUR AND OXYGEN. 103 ftinacy, the aétion of the peftle. The powder hada ftraw yellow colour. Its properties differ, we fee, from roll fulphur, which is remarkably brittle, and whofe {pecific gravity does not exceed 2. To afcertain whether this fuppofed oxide really contained It feems to con- oxygen, I treated 100 parts of it with nitric acie till the whole a coal was converted into fulphuric acid. The procefs was as te- though perhaps dious as the acidification of common fulphur, by means of the pee oe Te X ‘ i I e it to the fame acid. By nitrate of barytes I obferved a precipitate, name of oxida. which, after being reddened in a platinum crucible, weighed 667, indicating 160 parts of fulphuric acid; the fuppofed oxide had abforbed, of courfe, 60 parts of oxygen. Hence we have fulphuric acid compofed of 62.5 fuppofed oxide 37.5 oxygen 100.0 But 100 part of pure fulphur would have abforbed nearly 64 of oxygen, and formed 164 of fulphuric acid. Hence it follows that the fuppofed oxide is compofed of 97.6 fulphur 2.4 oxygen 100.0 Though the refult of a fimilar experiment was nearly the fame ; yet the proportion of oxygen is certainly too {mall to authorize us, in the prefent ftate of chemical analyfis, {o con- clude that the fuppofed oxide really contains 24 per cent. of soxygen : for fo fmall a deviation from the compofition of fulphu- ric acid, by acidifying common fulphur, as 2% per cent. may, very probably, be owing to an error of analyfis. At the fame time the uniformity of my refults inclines me to believe that this fuppofed oxide of the French chemifts really contains - fome oxygen. | 3. As no fatisfaGtory refult was likely to be obtained by ex- Oxigenation of pofing fulphur to heat and air, it became neceflary to try the ate Os effeéts of thofe chemical agents which are capable of commu- _ nicating oxygen to other bodies. Sulphuric acid could not be ufed, becaufe fulphur converts it into fulphurous acid; the effe& of nitric acid was well known; but the action of oxy- -muriatic acid had not been tried, Some of the foreign chemitts, indeed, 104 ON THE COMPOUNDS OF SULPHUR AND OXYGEN, indeed, affirm that fulphur takes fire when plunged into that gas; but they muft have, fome how or other, deceived them- felves. Oxigenation by 1 conneéted three Woulfe’s bottles in the fame manner, by oxymuriaticacide means of glafs tubes; furnifhed each with Welter’s tubes of Balen Sx Poa fafety. The firft contained an ounce troy of pure dry flowers gas was convert- of fulphur; the fecond was filled two-thirds with diftilled pete, pike water; and the third with a weak folution of cryftallized car- red liquid. bonate of potafh. A current of oxymuriatic acid gas was made to pafs through thefe bottles in the ufual way. The procefs lafted a confiderable time. The firft bottle was foon filled with the greenifh fumes of the gas; the fulphur gradually be- came moift and doughy, and the particles of it which adhered to the fides began to trickle down in drops; its colour changed to orange, and at laft, a fine red liquid made its appearance, The whole of the fulphur was gradually converted into this liquid. I then ftopt the procefs. Abundance of gas had paffed through all the bottles; the water in the fecond was, at one time, quite milky, but it recovered its tranfparency before the procefs was finithed. Dots of {ulphur were depofited along the glafs tubes which conneéted the firft and fecond phials ; but none in that which conneéted the fecond and third, the folution in the third phial effervefced precifely as in the ufual procefs for preparing hyper-oxymuriate of potafh, The gas: which efcaped was carbonic acid. No oxymuriatic acid gas could be diftinguifhed by its {mell in the {mall capfule of water into which a tube iffuing from the third bottle was pluaged. «=~ denominated As the red liquid obtained by this procefs has never before Cin aaa been examined by chemifts, and, as it differs very much in its properties from all other fubftances at prefent known, it will be neceffary to diftinguifh it by a peculiar name, I fhall call it fulphureted muriatic acid, till fome better name be thought of, == more than This liquid amounted to 1$ ounce meafures, exclufive of double the what adhered to the fides of the bottle; its i : weight of the in ol fpecific gravity fulphure was 1.623, It amounted, therefore, to 2.63 ounces, or more than twice the weight of the fulphur, exclufive of what had been volatilized during the procefs. It is green by Sulphureted muriatic acid is perfedtly liquid ; its colour is a gai fine red, intermediate between fcarlet and crimfon. When ftreaks of it run down the infide of the phial, they appear green by tranfiitted light, . When ON THE COMPOUNDS OF SULPHUR AND OXYGEN, 105 * When expofed to air, it fmokes at firft almoft as intenfely as It {mokes, and the .fmoking oxymuriate of tin of Lebavius; but the intenfity eae gradually diminifhes, and, at laft, refembles that of the moft con- dens blue colour; centrated muriatic acid a little heated. It is very volatile, ae tee: . : ; umes by ap- difappearing very rapidly when expofed to a moderate heat. proach of am- Its fmell has a ftrong refemblance to that of fea-plants, but 07145 and when ® : dropped into is much ftronger. The eyes, when expofed to its fumes, are water, leaves a foon filled with tears, and acquire the fame painful feeling as Ae of signer: when expofed to the {moke of wood or peat. acids du@ie, tte Its tafte is ftrongly acid, hot, and bitter, affe@ting the throat gee flakes with a painful tickling. By ee It converts vegetable blue papers to red; but the change . takes. place flowly, unlefs the paper be dipt into water; the paper is not corroded unlefs heat be applied. When brought near a phial of ammonia, denfe white fumes of muriate of ammonia make their appearance. © If it be held above a folution of nitrate of filver, yellow flakes precipitate in abundance. . If adrop of fulphureted muriatic acid be let fall into a glafs of water, the furface of the water becomes immediately co- vered with a film of fulphur; a greenifh red globule falls to the bottom, which remains for fome time like a drop of oil, but at laft is converted into yellow flakes; thefe flakes have an acid tafte, which they do not lofe, though allowed to remain in water for feveral days; they are very duétile, and continue fo, though left expofed to the air. 4. To afcertain the conftituents of this liquid I agitated 110 Chemical exami- parts of it ina very weak folution of potath, and then threw liquid Sane the whole on a filter: a yellow duétile fubftance was fepa- reted muriatic rated, which adhered very firongly to the filter ; what I could #4 feparate was put on a plate of glafs,and dried gently in the open air. It weighed 40, This fubftance had a yellow colour, and refembled half dry oil paint ; its tafte was hot; it adhered fo obftinately to the finger, that feveral days elapfed before every trace of it difappeared. When digefted for fome time in hot water, it fell into flakes of fulphur, and the water acquired an acid tafte. The flakes weighed only 34, and poffeffed all the properties of common fulphur. The water in which it had been digefted yielded, with nitrate of barytes, a precipitate which weighed 8, indicating the prefence of 1.92 fulphuric acid with nitrate of filver ; the precipitate amounted to 16, indicat- | ing , . 106 Chemical exe mination of the red liquid or ful- phureted muriatic acide Remarks on the fulphuret of mue Yiatic acid, ON THE COMPOUNDS OF SULPHUR AND OXYGEN. ing 2.88 muriatic acid: but the precipitate had a brownifh tinge, of which muriate of filver is deftitute. The 40 parts of yellow refiduum then contained 34.00 fulphur 1.92 fulphuric acid 2.88 muriatic acid 1.20 water or lofs 40.00 Seventy parts {till remain to be afcertained. They muft exift | in the folution of potafh. This folution, fuperfaturated+ with nitric acid, and treated firft with nitrate of barytes, and next with nitrate of filver, yielded precipitates indicating the pre- fence of 4.8 fulphuric acid and 36.45 of muriatic acid. The refiduum yield no farther precipitate with filver; but, when evaporated to drynefs, fome yellow cryftals were obtained, which gave traces of fulphur, but in too fmall quantity to be weighed. This analyfis gives us the following proportions : 35.00 fulphur 39.33 muriatic acid 6.72 fulphuric acid 81.05 28.95 lofs 110.00 . or per cent. 31.82 fulphur 35.75 muriatic acid 6.10 fulphuric acid os 73.67 26.33 lofs . This enormous lofs was owing, at leaft, in part, to the im- probability of feparating from the filter, the whole fulphure- ous mafs fo as to weigh it. This induced me to have recourfe to the following method of afcertaining the proportions of ful- phur in fulphureted muriatic acid. When fulphureted muriatic acid is thrown into warm nitric acid a very violent effervefcence takes place, and the whole mixture is thrown, witha kind of explofion, out of the veffel. If the acid be cold, the effervefcence is at firft flow, but heat is very foon evolved, and the fame effeéts produced. When the proportion of nitric acid is great, and. the fulphuret dropt in ON THE COMPOUNDS OF SULPHUR AND OXYGEN. 107 ut very flowly, the effervefcence continues moderate ; nitrous Chemical exa- gas and oxymuriatic gas being evolved, as was evident, from red liquid ore the fmell. I diffolved 100 parts of the fulphuret in nitric péureted muriatic acid. The liquid yielded, with nitrate of barytes, a folution #4 which, when properly dried, weighed 282 parts, indicating 67.6 parts of fulphuric acid; but 67.6 of fulphuric acid con- tain 26.3 oxygen. Hence 100 parts of fulphureted muriatic acid contain 41.3 of fulphur. If a cryftal of muriate of barytes be fufpended in fulphureted muriatic acid, no precipitate takes place ; neither was any ob- tained by agitating this falt in powder with the fulphuret. Hence I conclude, that the fulphuret does not contain fulphu- ric acid ; but that fulphuric acid is formed whenever the liquid comes in contaét with water. The oxygen cannot be fup- pofed to have been previoufly united to the muriatic acid fo- lution. For I find, by trial, that if the oxymuriatic acid gas be ftill made to pafs through the fulphuret, after it is once formed, fulphuric acid immediately makes its appearance in it. The oxygen then muft have been combined with the fulphur; the whole of which was in the ftate of an oxide. Whenever the fulphuret is diluted with water, that oxide undergoes decom- pofition, one portion of it abftraéting the whole of the oxygen from the other, fo that fulphuric acid and fulphur make their appearance together. If we fuppofe the proportion of fulphur and fulphuric acid obtained by the firft analyfis to be that which is formed when the fulphur is mixed with water, we fhall have the oxide of fulphur compofed of 31.82 fulphur 6.10 fulphuric acid or of 35.54 fulphur ‘ 2.38 oxygen or per cent. of 93. 8 fulphur 6. 2 oxygen 100. O But the fulphuret yielded to nitric acid 41.3 per cent. of fulphur. Hence it muft contain 44 per cent. of oxide of ful- phur. Sulphureted muriatic acid then contains 44,00 oxide of fulphur 35.75 muriatic acid 20.25 lols 100.00 108 ON THE COMPOUNDS OF SULPHUR AND OXYGEN. Chemical exa- The lofs is ftill very confiderable. Probably the greater part mination of the of jt is owing to the prefence of water ; the amount of which red liquid or ful- |, : pbureted muriaticit is impoffible to afcertain. acide The above analyfis conveys but an inadequate idea of the conftitution of fulphureted muriatic acid, becaufe the propor- tions of its conftituents vary confiderably, according to the pro~ cefs. The longer the procefs is continued the greater is the encreafe of muriatic acid, and the fmaller the- proportion of oxide of fulphur. 1 found a portion of fulphuret thus formed to contain 47.1 muriatic acid 35.2 oxide of fulphur 4.0 fulphuric acid —— 86.3 13.7 lofs It was this laft fulphuret that was obtained in the procefs in which the quantity of fulphuret which I got, as ftated above, was meafured, the fecond Woulfe’s bottle contained a folution of muriatic acid and fulphuric acid in water. Hence we fee that the fulphuret, after being formed, had been partly covered over by the oxymuriatic acid gas. The fulphuric acid ob- tained, by means of barytes, amounted to 36 grains; the mu- riatic acid to 139 grains. The third vial contained no fulphu- ric acid, but confifted of a mixture of muriate of potath, hyper- oxymuriate of potafh and carbonate of potafh. Remarks on the 5, The fulphuret of muriatic acid claims the peculiar at- fulphureted mu- : - ; ae ; Sete, tention of chemifis, not only on account of its compofition, which our previous knowledge would have induced us to _ confider as impoffible, but on account of the many remark- able properties whch it difplays. As I mean to referve a full account of its properties for a fubfequent paper, I fhall fatisfy myfelf at prefent with the following remarks. Sulphuret of 1. Sulphuret of muriatic acid diffolves phofphorus cold oe acid dif- with great facility. No effervefcence takes place ; the folu- olves phofpho- |. : use tion bas a fine amber colour, and is permanent. When eva- porated, the phofphorus remains behind with a little fulphur, and at laft takes fire. When the folution is mixed with liquid potath, the whole becomes beautifully luminous, and_phof- phuret of fulphur is precipitated. Sulphuret effer- 2. When mixed with alcohol, a violent effervefcence is vefces with al- produced, ether is immediately difengaged, and, what I did cohol, and forms ether. not EFFLORESCENCES OF WALLS, ~ 109 not expe? : this ether is mixed with fulphurous acid, and muft be re@tified in the fame way as fulphuric ether, which it refem- bles in fmell. ; 3. All the acids decompofe this fulphuret, fulphur ufuallyis difcompofed precipitating, except liquid fulphurous acid, which produces>y 4! acids 5 no change, and nitrous acid, which diflolves and decompofes it at the fame time. 4. The fixed alkalies dry produce with it a violent effervef-habitudes with cence and a very high degree of heat. When ammoniacal™ <5 gas is paffed through it, the veffel is filled with a fine purple fal-ammoniacal {ssoke, the whole becomes folidand of a deep red colour; but when mixed with water, fulphur is immedi- ately precipitated. 5, This liquid precipitates filver of a yellow colour mixed precipitates fil- with white, the white is a muriate of filver, the yellow is LS aera A compound of the oxides of filver and fulphur. It becomes brown when dry. Nitric acid decompofes it, diffulving the filver and acidifying the fulphur. iyi Further Experiments and Obfervations on the Efflorefcenees of Walls. Ina Letter from Dr. Bostock. To Mr. NICHOLSON. STR, INCE I fent you the analyfis of the faline efflorefcence Four eMoref- from the walls of Mr. Earle’s houfe, inferted in your journal: 0° ear for November laft, [ have had an opportunity of examining four other effloref{cences obtained from brick walls, the parti- _ culars of which I thall now detail. The firft of thefe was prefented to me by my friend Dr. ve firft ving Rutter, who difcovered it in confiderable quantity on the top Sie esi of the walls of his houfe juft below the roof. This falt hadnefia in every refpeGt the fame external chara¢ters with the one which I had before examined, and upon fubmitting it to the aétion of the fame chemical re-agents, fimilar refults were ob- tained. In addition to the former experiments, I compared the effeéts produced upon it by pure ammoniac, and by the éarbonate of ammoniac ; the former threw down a copious : preci- 110 EFFLORESCENCES OF WALLS. precipitate, while the latter had no perceptible operation ; 4 decifive teft of the exiftence of magnefia, which was fug- gefted to me by Mr. William Henry of Manchefter. This falt appeared, therefore, tobe a very pure fulphate of mag- nefia. The fecond ef- The fecond efflorefeence which I examined. was obtained ad pe) from the outer wall of a ftable, which had been ereéted for with indication fome years. It differed on its appearance from the two of muriatic acids eer; inftead of fhooting out from the wall in fpiculz of confiderable length, it appeared like a powder feattered over the furface, occupying diftinét, round patches, fo as in fome degree to refemble the growth of a grey lichen. The bricks on which this efflorefcence appeared were in general of a 2 fofter texture than thofe of the reft of the wall. Though it occupied a confiderable extent, it was difficult to colleét it in any quantity, -but I obtained fufficient to fubjeét it to the fol- lowing experiments. The falt was diffolved in warm water, filtered and cryftallized ; the cryftals were very foluble at the common temperature of the atmofphere. Muriate of Barytes added to the folution produced a copious precipitate; car- bonate of pot-afh, pure pot-afh, pure ammoniac and oxalic acid were refpeétively added to the folution, but produced no effect. Nitrate of filver caufed a precipitate, but only in {mall quantity. From thefe experiments it appeared that the falt in queftion confifted of the fulphuric acid, mixed with a fmall proportion of the muriatic, and combined with one of the fixed alcalies. From the form of its cryftals I conceived that the fulphuric acid was in this cafe united to foda, but the quantity of falt which had been procured, was not fufficient to enable me to determine accurately from this circum- ftlance. A more decifive teft between the fulphate of foda and the fulphate of pot-afh, is the property which the latter alone poffefles of forming alum with the acid) fulphate. of alumine, I accordingly prepared a quantity of this fubftance ; to one portion of it fulphate of pot-ath was added, and to the: other fome of the falt under examination. By gentie evapo- ration and fubfequent cooling, the firft produced very evident cryftals of alum, the latter only formed a confufed mafs. This. I confidered as a fufficient proof that this faline efflorefcence was the fulphate of foda. . Third efforef- Lhe third efforefcence was obtained ‘from the inner wine of cence {ulphate a brick houfe which was then ereéting ; it had all the internal chae , EFFLORESCENCES OF WALLS. 111 chara¢ters of the faline efflorefcence from the ftable, and whenof foda nearly fubmitted to the fame chemical re-agents, differed from itP’'® only in exhibiting flighter traces of the muriatic acid; this falt was therefore a fulphate of foda nearly in a ftate of purity. The walls of the falt water baths in this town are covered Fourth efMoref- with a ftucco, which is in feveral places bliftered and moulder-ir.? or pe ingaway. ‘The parts of the plaifter which are decaying, are water bath, was covered with a copious efflorefcence, which has the appear-°*bonate of foda, ance of a fine white down. Some of this I colleéted and examined. It was diffolved in warm water and filtered; the folution was not capable of being regularly cryftallized, but formed a white mafs, eafily foluble, poffefling the acrid tafte of a fixed alcali, and affeéting the colour of teft papers in the fame manner. A brifk effervefcence was excited by the ad- dition of an acid, and from this circumftance and the effe@ of the different re-agents, I conceived it to be one of the fixed alcalies. In order to determine whether it was an uncom- bined alcali, and to which of thefe bodies it ought to be re- ferred, I afcertained what quantity of the fulphuric acid was requifite to faturate a known weight of the falt, and after- wards, employing the fame acid, compared it with the quan- tity which the fame weight of alcali required. As the falt had not attraéted any moifture from the atmofphere during a period of fome weeks, I eoncluded it to be foda, and I ac- cordingly found that the fame quantity of fulphuric acid fafu- rated equal weights of foda, and of the falt under examina- tion; the folution being flowly evaporated, formed well- , marked cryftals of the fulphate of foda. That part of the walls of the bath on which the falt had efflorefced in the gteateft quantity, was out of the reach of the immediate action of the fea water; but it is probable that the fand of the fhore had been mixed with the lime, for by examining a quantity of water which had been digefted upon a portion of the plaifter, it yielded a very copious precipitation by the ni- trate of filver, and this rendered it highly probably that the Probably formed mortar contained the muriate of foda. It might therefore beby procefs for- conjeCtured that the foda in this cafe was accidentally formed ¢, ey re by the fame procefs which, according to Mr. Accum’s sCcount in the 2d vol. of the Journal, p. 243, is employed defignedly in Pruffia for obtaining it, by the decompofition of common dale... I hall 112 EFFLORESCENCES OF WALLS. Invettigation of I fhall conclude this communication by detailing to you the the origin of ~~ progrefs which 1 have made in inveftigating the origin of the ao ere -- fulphate of magnefia, which appeared in Mr. Barle’ s houfe. bricks of Mr. Before proceeding farther, it will be proper to obferve that Eaile’s houfee the efflorefeence was here altogether confined to the bricks, the mortar which united them being entirely free from it, and that rain water only had been employed in tempering the clay. It remained therefore to examine with accuracy, whether any falt, foluble in water, exifted ready formed in the clay, and what were the component parts of the clay itfelf. To afcer- tain the firft of thefe points, 60 grains of the clay. powdered and dried were well wafhed with boiling water; the water was filtered and evaporated, and the refiduum carefully col- The clay con Jegted; it did not weigh 4 of a grain. It was re-diffolved in tained a por- is i pts : tion of mu- water; it produced a copious precipitate with the muriate of riate and fulphate barytes, and the nitrate of filver; a very. faint cloud with ea oxalic acid and with pure pot-afh; ammoniac produced no effect. The ready formed falts appeared therefore to be the fulphate and muriate of a fixed alcali, with a minute fortion of the muriate of lime, the whole however exifting in very {mall quantity, \ ee a ee The clay itfelf was next examined ; it was found to.confitt ortion OF mage . . > . . I . a. : principally of filex and alumine in the proportion of about three to one; the quantity of lime was very fmall, though its exiftence was detected by the oxalic acid; its colour Wed that it contained iron, and I alfo found that about ive parts in the 100 confifted of magnefia. From this exa« mination it appeared that one of the component parts of the falt exifts in the ‘clay ; I attributed the formation of the ful- phuric acid to the fulphur which is frequently met with in our coals, and which I conceived might unite with oxigen, during Experiment to the burning of the bricks, _I attempted to put. this aétion to fhew whether : fidietu gf Rett the teft of experiment, and accordingly I formed a. pafte of coals had given pipe clay and calcined magnefia in the proportion of 95 to “igi aici five ; this was placed in a crucible, furrounded. with {mall coal mixed with a quantity of fulphur; the crucible was then kept for fome time in a firong heat. I was not able to dete@ | the prefence of the fulphuric acid in the clay that was thus baked, but fo many circumftances. might .aétually take place in the formation and burning of the bricks, which we have it not in our power to imitate in the laboratory, that I do not confider the hypothefis difproved by my want of fuccefs. In EFFLORESCENCES OF WALiS. 113 Th analyfing the clay I proceeded nearly upon the plan Analyfs of the pointed out by M, Vauquelin in the 30th vol. of the Ann, Slay, &c. de Chimie. This operation is however fo tedious, and requires fo much nicety in the management, that I made fome attempts to af= certain the exiftence of magnefia in the clay by a fhorter pros eels. The firft method which I employed was fuggefted by an obfervation of Mr. Kirwan; he ftates that alumine is fuf- ficiently difcriminated from magnefia by the greater folubility of the latter in dilute fulphuric acid ; but it appears that the dif- ference of folubility of thefe two fubftances cannot be em- ployed as a teft of the prefence of magnefia where it exifts only in fmall proportion ; for I found that the fulphuric acid: diluted with above 200 times its weight of water, after being in contaét with pure alumine for the {pace of 10 minutes only, had acted upon the alumine fo far that a precipitate was formed in the fluid by the addition of ammoniac, The acetous acid is ftated as pofleffing a much more power- ful ation over magnefia than over alumine; but upon trial the fame objeétion occurred againft its ufe as in the former inftance, The property which the magnefian falts poffefs of being decompofed by pure ammoniac but not by the carbonate:of ammoniac, feemed to offer a method by which the fulphates of magnefia and of alumine might be feparated when mixed together in folution, and by which means confequently t * prefence of magnefia might be dete@ted in the clay under examination. But I found that though the fulphate of mag- nefia alone is not decompofed by the carbonate of ammoriiac, _ yet that when a mixed folution of alum and the fulphate of magnefia is fubjected to the a€tion of the carbonate of ammo- niac, both the alumine and the magnefia are precipitated, fo _ that when the fluid is feparated by filtration, the addition of pure ammoniac produces no farther effeét : fe After I had made the unfuccefsful experiment related above refpeéting the formation of the fulphuric acid, I receivéd the laft number of your Journal, containing a communication from Mr. Gregor, in which he gives an account of the produétion of the fulphate of magnefia from the afhes of pit-coal. He Mt.Gregor’s ete attributes the produétion of this falt to the decompofition of periment notape _ the fchiftus and pyrites which are commonly found in coal, ope ao VoL. VI.—COctoner, 1803, I and as coal afhes were not uled, 314 ON EVAPORATING FURNACES. and by heating a mixture of thefe fubftances he fucceeded in forming the falt artificially. The fuccefs of his experiment feems to prove the truth of the theory, at leaft in the parti- cular inftance in which he obferved the efflorefcence : but in thofe cafes where the falt evidently proceeds from the fub-* ftance of the brick, and where the magnefia has been found to exift previoufly in the clay, the idea of Mr. Gregor appears lefs applicable, fo far as regards the origin of the magnefia ; but in both the proceffes the fulphuric acid is equally fuppofed to be derived from the pyrites. Mr. Gregor fuggefts that coal afhes might have been mixed with the clay of which thefe bricks were formed ; but I find upon enquiry that this was not the cafe. Iam, Liverpool, Aug. 30, Your obedient fervant, 1803. JOHN BOSTOCK. a a PS SSS SSE SE SY be Philofophical Obfercations on the Caufes of the Imperfeétion of evaporating Furnaces, and on a New Method of conftructing them, for the economical Combuftion of every Defcription of Fuel. By C. Curaupau, correfponding Member of the Pharmaceutic Society of Paris *. On the come W orwirustanpinc the attempts already made to buftion of fuel end conftruétion of furnaces. introduce ceconomy in the ufe of the combutftibles neceffary to the manufactures, we ftill ufe them with confiderable wafte, In all cafes a much greater quantity of fuel is confumed than is needful to keep up the ebullition in evaporating furnaces, or to produce the requifite temperature in furnaces for other purpofes. It may be eafily conceived that this fuperfluous con- fumption muft in large eftablifhments be attended with great lofs, and muft eventually tend to produce a fcarcity of fuel in the market. It therefore becomes us for both reafons to en- deavour to prevent a fcarcity, of which future generations might with juftice accufe us of being the authors, unlefs. we ferioufly occupy ourfelves in fearch of the methods of burning wood with more economy, Many very remarkable improve- ® From the Annales de Ghimie, No. 138¢ ments ON EVAPORATING FURNACES. 115 ments have indeed been made in the conftruétion of furnaces On the com- within thefe few years, but they are only advances towards pe fain perfection, and are yet very far from being carried to the ex-of furnaces. tent of which they are capable. This will no doubt be the cafe with the alterations Iam about to propofe ; for thefe will enable us to make new obfervations, which moft probably will lead to further alterations ftill more important. Concerning Evaporatory Furnaces. The phyfical impoffibility of raifing the temperature in eva- porating furnaces as they are at prefent conftruéted, is one of © the caufes which has always appeared to me moft ftrongly in- imical to their improvement. For it muft not be imagined that * the intenfity of the heat will be in proportion to the quantity of. matter in ignition, or that caloric will not be more copi- oufly produced by the fame quantity of combuftible under certain circumftances than others; as for example, when the temperature is already very high, the produéts of heat from a combuftible fo fituated will be much more confiderable than thofe from the fame combuftible burned in a furnace, the tem- perature of which is conftantly depreffed by the evaporation of the liquid in the boiler. To prove that it is only by virtue of a temperature already elevated that we can obtain an advantageous combuttion, I fhall take Argand’s lamp, which will afford a comparative inftanag on a fmall fcale of the effeét produced by the intenfity of heat during combuftion. When thefe lamps have their glafs chim- “ney, they afford a very brilliant light, and the oil will emit no fmoke. But if the chimney be taken off, the oil will immedi- ately burn duller, the light will be lefs intenfe, and the wick will give out fmoke. This effeét fhews that it is the current of air in the chimney, and the heat it keeps up round the wick, which contributes to the effeét of the combuftion. What fill adds weight to this opinion is, that the perfection to which this kind of lamp is brought depends principally on the form and proportions of its glafs chimney. This example muft then naturally lead us to think that eva- porating furnaces, as they are made at prefent, cannot advan- tageoufly promote combutftion, fince the bottom of..the boiler, which is continually kept at the fame degree of heat by the evaporation of the liquid in boiling, conftantly prevents the . 12 rife 116 On the com- buftion of fuel and conftru€tion of furnaces. ON EVAPORATING FURNACES. rife of the temperature, whence it refults that the heat whieh is infufficient to produce a complete combuftion of the inflam- mable particles, will rather produce gazification than oxigi- nation. This volatilization of the particles of combuftible bodies which efcape combuftion, and’ which pafs fucceffively into the ftate of permanent gales, will alfo abforb a quantity of heat neceffary to their gafeous conftitution, which, together with the effeéts of the current of air, will tend to lower the interior temperature of the furnace, and to ae the procefs of combuttion. Thefe remarks, which perfeétly agree with all the pheno- men of combuftion, thew that the oxigen of the atmofphere does not act with much efficacy on ccinabiulite bodies, except when they are immerfed in it at an high temperature, and that to apply an intenfe and uniform heat to an evaporating furnace without lofs of the combutftible, it fhould be produced in a fire- place, having a current of air, and fo far diftant from the boiler that the temperature may be raifed gradually and at pleafure. By this means all the particles of the combuftible matter will be in a ftate favourable to their oxigination; and the whole quantity of radiant heat produced by the reaétion of the oxi- gen upon the combuftible, will be difengaged and employed without lofs. That which under fimilar circumftances conduces ftill farther ‘to encreafe the action of the oxigen, is its continual renewal. For the higher the temperature of -a furnace is raifed the more eafily the outer air will enter; and fo likewife when the igni- tion is carried to a high degree, it becomes neceflary and ad- -vantageous to check the current of air, not by clofing the door or lower opening of the furnace, as is generally done, but ra- ther by contraéting or even clofing the upper aperture of the chimney. By this means the heat becomes concentrated in the body of the furnace, and has no other paflage than through the liquid in the boiler, This remark on the method of checking the current of air . by the top of the chimney, may alfo be applied to furnaces of fufion, and in cafes where it is required to maintain the heat of a metal without expofing it to the oxigenating aétion of a current of air in a ftate of ignition. General ON EVAPORATING FURNACES. General Remarks on the Conftruétion of Furnaces. That part of the fire-place which is to fupport the greateft heat, fhould be made of very refractory bricks. The beft ce- ment or mortar for bricks, in all cafes where a bad conductor of heat is required, is a mixture of equal parts by meafure of tan and-clay. The tan prevents the cement from cracking, and produces an adhefivenefs which, when dry, gives it a great degree of firmnefs. Furnaces may alfo be conftruéted with this Bre and on the fame principles with thofe of evaporation, which Iam about to defcribe. : _ Furnaces intended for ftrong heat, fhould be externally co- vered with a thick wall, conftru€ted with the mortar of tan, By this means very little heat will be loft. All furnaces fhould be fo conftru€ted as to have the power of clofing the upper aperture of the chimney at pleafure, in order to check the combutftion, and concentrate the heat within the furnace, when- ever this becomes neceffary. When the temperature is very high, it is particularly neceflary to regulate the iffue of the current of air fo as to prevent its too {peedy circulation through the furnace, which, in certain cafes, is prejudicial to the fuc- cefs of the operation. By uniting all thefe conditions in furnaces, a certain faving ef one fourth of the fuel will be made, and the combuftion will be produced without any appearance of {moke. I infitt more particularly on this remark, becaufe it is clearly and phy- fically proved that no combuftible « can be completely burned if {moke be produced. Defeription of an Evaporating Furnace, in which the Temperature may be ruifed at Pleafure. 117 For common furnaces, the aperture of the vaylt A, Plate Defcription of VI. thould be four decimetres (153 inches) wide, by three # furnace ia decimetres and a half (13% inches) in height; B is the part of _ the vault in | which the combultion is performed. This vault - muft be. at. leaft two metres (64 feet) inlength, C reprefents _a boiler of one metre and a half (nearly five feet) in diameter, and of the fame depth; it is fet in a brick furnace. The interval from the bottom of the bojler to the bafe of the furnace muft be at moft one decimetre (about four inches.) It mutt be obferved in the conftruction of furnaces, that the brick- work fhould be gradually floped towards the boiler, and to re- duce evaporation. 118 STATE OF VAPOUR IN THE ATMOSPHERE. duce the fpace to about three centimetres (about an inch.) It muft be thus continued to within one decimetre of the edge of the boiler ; and muft then be brought into contaét with it. D is an aperture of two decimetres wide by one in height (about eight inches by four) communicating with E. But at the fide of the angle a, this paflage for the heat muft be made of one metre (three feet three inches) in width, by one decimetre (about four inches) in height, and this proportion continued to the aperture E. F is a fecond boiler, intended to be heated by means of the excefs of heat from the firft; many others may be applied in fucceffion, if required. G is an aperture with the fame pro- portions as D, At the angle b, it muft be obferved to’ make the aperture of the chimney five decimetres by two (192 inch. by 73 inch.) and to continue this proportion to about two thirds of its height. The aperture may then be contraéted fo that, at its upper extremity, it may not be lefs than one decimetre by three (about four inches by twelve.) This part of the chim- ney fhould be fo conftruéted as to be able to clofe it conveni- ently, when required, Se en XI. Correction of a Miftake in Dr. Kirwan’s Effay on the State of Vapour in the Atmofphere. By Mr. DaTon. To Mr. NICHOLSON, o 18, aise: I TAKE the liberty of requefting you to corre&t a miftake in ing Mr. Crof- Dr. Kirwan’s effay on vapour, copied in your laft number, pase page 246. In treating upon the height of clouds, he obferves, mum heightof “ In lat. 54°, in Cumberland, Mr. Crofthwaite obferved none the clouds. “lower than 2700 feet, and none higher than 3150, in the “« courfe of feveral years.” For this he refers to my meteoro- logical obfervations, page 41. The faéts there ftated, how- ever, are fo very different from thofe above mentioned, that I conclude Dr. Kirwan has not feen the book, and has been mifinformed. The account referred to is, that Mr. Crof- thwaite obferved the heights of the clouds ufually three times a day for five years, by remarking their interfeGtion with Skid- daw (a high mountain near Kefwick.) ‘The refult was, 4 Clouds STATE OF VAPOUR IN THE ATMOSPHERE, 119 Clouds from 0 to 100 yards above Derwent Lake, 10 times. WOMWBABI4 2S) WBisinp peli’ ow 49 200'3'''300)" ¢ae,e 6 - - 62 ' 300 - 400 - - - - 179 400+ 500 - ab ive - 374 500 - 600 2 sHiiogts' jews 486 600 4),,700 (4 Pee © . 416 FOO\S>-800 i200 )\« - - 367 s00- 900. -« - aratt 410 900 - 1000 ~ abvatlgerd smd ce SB 1000- 1050s - site he & 419 above 1050 ° - = - 2098 ——— Total 5381 His obfervations could not be particular above 1050 yards, No maximum that being the perpendicular height of Skiddaw. There is not ei 4s dias therefore any maximum of height fo much as hinted at ; and author’s obfer- the minimum is 0, or when the clouds reft on the sea iin event occurring in every part of Great Britain two or three times a year. Were we to forma conjeéture from the above obfervations relative to the greateft height at which clouds are formed in this country in ordinary, it would be about 1 mile; but in fummer they are probably fometimes 1} mile above the level of the fea. Confidering the great fervice that Dr. Kirwan has rendered Obfervations, or to meteorology and chemiftry, and my own obligations to him a age on thofe accounts, it is unpleafant for me to fignify diffent from and Mr. Dalton’s the doétrine he inculcates refpeéting the ftate of vapour in the ellos atmofphere. At the fame time that his interefting feries of pheric vapours eflays in the eighth volume of the Tranfaétions of the Royal Irith Academy were in the prefs, my effays on the force of va- pour from water and other liquids, both in a vacuum and in air, and on evaporation, publifhed in the Manchefter Tranf- aétions, Vol. V. Part 2, were alfo in the prefs. He holds the notion of a chemical folution of water in air; and I maintain that vapour fubfifts in air as it does in vacuo, conftituting a pe- culiar atmofphere, mixing but not combining with any of the gafes of the compound atmofphere. On my principle the den- fity of the aqueous atmofphere at any height is totally inde- pendent of the denfity of the compound mafs of - air, and is to be afcertained by ‘knowing the denfity of vapour at the earth’s 120 Eafy method of fecuring decayed timbers in builds ings, &c. METHOD OF SECURING DECAYED TIMBERS... earth’s furface, and its fpecific gravity ; in the fame way as we would afcertain the denfity of the oxygenous or azolic at- mo({pheres, or one of hidrogen, at any given height, having the like data. It has been a matter of furprife to me, that moft or all of my effays publifhed in the volume above mentioned, have been - copied and circulated in one or other of our periodical publi- cations, except thofe two juft mentioned, which appear to me by far the moft important, and which feem too to have been confidered as fuch by the forcign journalitts. Iam your’s, &c. : J. DALTON. Manchefter, Aug. 22, 1803. Xi. Cheap and effectual Method of fecuring Beams of Timber in H oufes or elfewhere, which have been injured by the Dry Rot, or are decayed by Teme. By Mr, James Woart.* W urre the ends of the girder are: decayed by time, or injured by the dry rot, they are often taken out, and new onés put in their place, at a great expenfe: and if the dry rot is in the walls, the ends of the new girder will be in danger se of it again: fuch was the cafe at Eliham, in Kent, where in one hotife there were three new girders to one floor in the fpace of twenty years ; whereas my method will be found infallible, executed at much lefs expence, and not fubjeét to the dry rot, becaufe the end of the girder may be cut off clear from the wall; and if an air grate is put on the outfide, fo as to admit air to the end of the girder, it will remain fafe from injury. Plate 1X. Fig, 2.t-—A, fhews the end of the decayed girder, with the braces applied upon it. . BB, * Memoirs of the Society of Arts, 1802. A reward of twenty guineas was awarded to the inventor, who, in an introduétory let- ter ftates, that by the iron braces, of tefs coft than 20]. he fecured the houfe of Hannege Legg, Efq. at Putney in Surry, which could not have been done by new beams without lofs, derangement, and . sharges to the amount of eight hundred pounds. + There are two plates i in the Tranfactions, the fecond of which forms METHOD OF SECURING DECAYED TIMBERS. 1} BB, the templets or wall-plates on which the girder refts. Eafy method of CCCC, one of the iron levers for raifing and fupporting Spirria ingle hy the girder (there being a fimilar one on the oppofite fide.) ings, gc. This lever is moveable on a pin D, which comes through a hole in the lever, diftant about two feet from the end of the girder.. This pin forms part of a collar E bedded in the girder. The lever is fix feet long, three inches wide, and three fourths of an inch thick, and extends from the wall-plate along the fide of the girder. The extremity of the lever is moveable on another pin F; projecting through it from an upright iron G, bedded in the fide of the girder, and carrying a nut and fcrew, which aé& on acrofs plate H, through which the upright iron paffes. At the other end of the lever, next the templet, is an iron collar I, bedded in the girder, which collar may be raifed or Jowered at pleafure, by means of the nut and fcrew K, form- ing part of it; and by aid of the cap-plate L, which preffes upon the lever, and alfo clafps it to the girder by its bend at L. As Plate 1X. Fig. 2, fhows only one fide of the girder, and, as has been before obferved, there being alfo a finular lever on the oppofite fide of the girder, their feparate parts, method of conneéting them, and their mode of aétion, are more fully explained in Plate VII. Fig. 1, 2, 3, where the fame letters are made ufe of to point out the feveral parts. Fig. 1.—E, thows the whole of the collar to be bedded in the fide and bottom of the girder, and the pins D D, on which the two levers are moveable. : Fig. 2.——The cap-plate H, the two upright irons G G, with their nuts and fcrews, which aét upon the extremities of the two levers by means of their pins F F. Fig. 3.—The collar I, on which that end of the girder next the templet refts, the fides of which collar are bedded in the girder. CC are the claws or bended legs of the two levers. _ which go into the templet. Lis the cap-plate, K K are the nuts and fcrews. At Mr. Legg’s houfe, where the levers above eb were applied, the beams of the roof were fo decayed that the roof was in imminent danger, the bearings were entirely rot- forms Plate VII. of our prefent number. The other unfortunately was neglected to be fent to the engraver’s, and the miftake not dif- covered till too late. It will be given in our next, ten, 122 METHOD OF SECURING DECAYED TIMBERS, Eafy method of ten, and the beams were funk three fourths of an inch, and fecuring decayed prefling againft the wall for fupport ; if there had not beena timbers in build- : ; ings, &ce large cornice underneath, fupported by brackets, the whole roof muft have fallen. To put them in order, I firft put fhores or fupports under each end of the two beams, on which the double roof lay, and then forced the four fhores at once, for the fecurity of the roof, the work, and men. The iron levers, C, were then prepared, let into the templet, and fixed on each fide of the beam, on the pins D, projeéting from the collar E, bedded in the beam, about two feet from itsend. When the whole ap- paratus was ready, on {crewing the nuts on the upright irons G, at the extremity of the levers, the beam was raifed to its proper height with great eafe, although it was fuppofed there was above two tons weight on each beam, on account of the lead gutter, and gutter-beam betwixt the double roof, and the rich ornamented ceiling attached to the joift, which was notin the leaft deftroyed except where the iron collar E was fixed, which was put up from the under fide by cutting the ceiling the width of the collar. Thefe beams were fo decayed, and fo hollow, that the common method of bolting plank on each fide of the beam would not have been fafe; and if it could have been executed, thenew planks would have been fubje& to the dry rot, and the roof ftill in danger, which is now prevented, as the iron is not affected by it. The beam-ends were cut clear from the walls, and the beams are fufpended by means of the iron levers, whofe feet reft on the templets of the walls. An air grate was made, on the outfide of the wall, to admit a. current of frefh air to the ends of the timbers. The roof is now much fafer than when originally made, as the timber is fecured from decay ; and, owing to the collar E, the bearings are now two feet fhorter at each end of the beam ; the bearing on each beam being now, in the whole, four feet fhorter than in its original ftate. | After ,the beams were brought to their proper height, and the levers and ferews adjufted, fcrew-bolts were put into the timber, through holes purpofely left in the lever, betwixt D and F, and the whole work thus perfeétly fecured. At the other end of the girder, M, Plate IX. is fhown an- other method of fupporting timbers, where the ends are de- cayed. The METHOD OF SECURING DECAYED TIMBERS, 193 __» The particular irons ufed in this way are thown in Plate VII. Eafy method of Fig. 4. N is-a collar for the girder ; O, aniron frame which gracias pce ti refts on the templet; P P, two nuts which raife the collar N. ings, &Ce R R fhow the clawed ends of the two bars of iron,. extending under the girder, bedded. therein, and fcrewed to it at their extremities, about five feet diftant from the templet. Fig..5, is one of the iron bars laft mentioned. S is the claw or lap which projeéts over the collar N. T is the place where it is {crewed into the girder. Fig. 6 and 7. Plate VII. explain a third method of fecuring decayed timbers. Fig. 6, gives a fide view of a decayed girder: a, reprefents the templet; 5b, an iron lever, fix feet long, nearly- ftrait, being only cambered one inch, three inches wide, and three quarters of an inch thick ; this lever-extends along the fide of the girder c, and is fecured firmly toit by the fide irons d dd d, which are two ‘inches wide, and full half an inch thick, point- edat the ends. The higher ends of thefe fide irons are driven into the girder, and the lower points pafs through holes in the lever into the lower part of the girder, and are held clofe to the girder by ftaples eeee: the fide iron next the templet may be fixed flanting, in order that it may enter founder wood. A claw, f, which is part of the lever, refts on the wall plate a, and is bedded in it ; an iron plate, g, lying under the girder, _ and let into it, paffes through the lever at 1, conneéting it with a fimilar lever on the oppofite fide, and which affiits in the fame way to fupport the girder: 7 isa flooring joift, to fhow how deep the levers are inferted therein. Fig. 7, thows the under part of the fame girder; bb, are the bottoms of the two levers above mentioned, fixed to the girder by the fide irons and ftaples before defcribed; kk, the broad feet of the levers which lie flat upon the wall plate; ff the two claws projecting from the feet, in order to bed in the wall plate ; 7277 are joifts, partly cut through, to admit the iron levers to lie clofe to the girder: g thows the iron plate or collar on which the girder bears; it is tarnéd up an inch anda half at each end, to keep the levers clofe to the fides of the girder. This collar fhould be made out of inch-bar iron, with points projecting from it, in the fame manner as the collar at DD, Fg. 1, to conneét it with the levers, by paffing through holes made through them for that purpofe. — To 124 Introductory ubfervations on ebe ufelefs trees “in orchards. BRANCH GRAFTING. To fix the levers, put a fhore two feet fix inches from the wall, under the girder, to fupport it ; then cut off the decayed end, and take out the templet, or part of the wall plaie, if decayed ; and put in a ftone templet for the irons to reft upon, with mortices in the ftone to admit the claws of the lever : then fit the collar underneath the girder, two feet from the wall, to anfwer the holes in the lever ; make an incifion in the joifts three-fourths of an inch wide, and three inches deep, to admit the levers; fix the levers on each fide with the collar, fo as to force up the. levers together; then with flight fhores force up the ends of both levers together, and fix the fide-irons firm. The girder will thus be perfeétly fate. The templet or wall plates, on which the levers reft, are made of Portland ftone, three feet long, nine inches wide, and five inches deep, with incifions or mortices made therein for the claws of the levers. ; _ Certificates, confirming Mr. Woart’s improvements, were received from the commillioners of the navy, from Mr. Jofeph Harris, fmith, at Putney, and Mr. George Smith, furveyor, at Putney. XIII. Account of the Method of extreme Branch. Grafting. By the Inventor Witt1amM Fatrman, Ly/q.* STR); From much converfation with Mr. Bucknall on the idea of improving ftandard fruit-trees, we could not but remark that in apple orchards, even in fuch as are moft valuable, fome were to be feen that were ftinted and barren, which not only occafioned a lofs in the produétion, but made a break in the rows, and fpoiled the beauty and uniformity of the planta tion, To bring thefe trees into an equal ftate of bearing, fize, and appearance, in a fhort time, is an objeét of the gréateft importance in the fyftem of orcharding, and alfo for the * In a letter to Charles Taylor, Efq. Secretary to the Society of Arts, and inferted in their Memoirs for 1802. For which the filver medal was awarded. recovery BRANCH GRAFTING. 125 recovery of old barren trees, which are fallen into decay, not “fo much from age, .as from the forts of their fruits being of the worn-out and deemed nearly loft varieties. Having long entertained thefe thoughts, and been by no means inattentive to the accomplifhment of the defign, I ate tempted to change their fruits by a new mode of engrafting, and am bold enough to affert that I have mioft fortunately New method of fucceeded in my experiments; working, if I am to be allowed &ti"é+ _to fay it, from the errors of other practitioners, as alfo from thofe of my own habits. My name having feveral times appeared in the Tranfactions of the Society for the Encouragement of Arts, &c. and having the honour of being a member of that Society, I thought no pains or expence would be too much for the completion of fo defirable an improvement. Under thefe impreffions, and having many trees of this defcription, I made an experiment on three of them in March 1798, each being nearly a hundred years old. They were not decayed in their bodies, and but Jittle in their branches: Two of thefe were golden pippins, and the other was a golden rennet. Each likewife had been paft a bearing ftate for feveral years. I alfo followed up the _ praétice on many more the fucceeding fpring, and that of the taft year, to the number of forty at leaft, in my different plantations *. ' The attempt has gone fo far beyond my moft fanguine exe pectation, that I beg of you, Sir, to introduce the fyftem to the Society, for their approbation ; and I hope it will deferve the honour ofa place in their valuable Tranfaétions, I direéted the procefs to be conduéted as follows: Cut out Inftru@ions for all the (pray wood, and make the tree a perfe@t tkeleton, leav- PR PonNs ste ing all the healthy limbs; then clean the branches, and cut the top of each branch off where it would meafure in circum- ference from the fize of a fhilling to about that of a crown -piece. Some of the branches muft of courfe be taken off where it is a little larger, and fome f{maller, to preferve the canopy or head of the tree; and it will be neceflary to take out the branches which crofs others, and obferve the arms are left to fork off, fo that no confiderable opening is to be perceived when you ftand under the tree, but that they may reprefent an .@ The average expence I calculated at 2s. 6d. each tree. 2 uniform 126 Pofition of the rafts. Cement and general prepara- tionand ma- hagement. Great advane tages of leaving the tree of its full fize. —and increafing its powers. BRANCH GRAFTING. uniform head. I muft here remark to the praétitioner, when he is preparing the tree as I direéted, that he fhould leave the branches fufficiently long to allow of two or three inches to be taken off by the faw, that all the fplintered parts may be removed. . The trees being thus prepared, put in one or two grafts at the extremity of each branch ; and ‘from this circumftance I with to have the method called extreme branch grafting. A cement, hereafter defcribed, muft be ufed inftead of clay, and the grafts tied with bafs or foft ftrings. As there was a confiderable quantity of mofs on the bodies and branches of the trees, I ordered my gardener to fcrape it off, which is effe@tually done when they are in a wet ftate by a ftubbed birch broom. I then ordered him to brufh them over with coarfe oil, which invigorated the growth of the tree, aéted as ~ a manure to the bark, and made it expand very evidently ; the old cracks were foon, by this operation, rendered in- vifible. All wounds fhould be perfe@ly cleaned out, and the medica- tion applied as defcribed in the Orchardift, p. 14. By the beginning of July the bandages were cut, and the fhoots from the grafts fhortened, to prevent them from blowing out. I mutt here, too, obferve, that all the fhoots or fuckers from the tree muft enjoy the full liberty of growth, till the fucceeding fpring, when the greater part muft be taken out, and few but the grafts fuffered to remain, except on a branch where the grafis have not taken: in that cafe, leave one or more of the fuckers, which will take a graft the fecond year, and make good the deficiency. This was the whole of the procefs *. By obferving what is here ftated, it will appear that the tree remains nearly as large when the operation is finifhed, as it was before the bufinefs was undertaken ; and this is a moft effential circumftance, as no part of the former vegetation is loft, which is in health fit to continue for forming the new tree. It is worthy of notice, that when the vivifying rays of the fun have caufed the fap to flow, thefe grafts inducing the fluid. through the pores to every part of the tree, will occafion in- * The fyftem fucceeds equally well on pear, as alfo on cherry trees, provided the medication is ufed to prevent the cherry’ tree from gumming. numerable BRANCH GRAFTING.’ 127 numerable fuckers or {cions to ftart through the bark, which, together with the grafts, give fuch energy to vegetation, that in the courfe of the fummer the tree will be a€tually covered ever by a thick foliage, which enforces and quickens the due circulation of fap. Thefe, when combined, fully compel the roots to work for the general benefit of the tree. In thefe experiments I judged it proper to make choice of The mot luxu- grafts from the forts of fruits which were the moft luxuriant in halt Pe their growth, or any new variety, as defcribed in the feven- teenth and eighteenth volumes of the Society’s Tranfaétions,. by which means a greater vigour was excited; and if this obfervation is attended to, the pratitioner will clearly perceive, from the firft year’s growth, that the grafts would foon ftarve the fuckers which fhoot forth below them, if they were fuffered to remain*. With a view to accomplifh this grand objeé of improvement, I gave much attention, as I have before obferved, to the general praétice of invigorating old trees ; and I happily difcovered the error ofthe common mode of engrafting but a fhort diftance from the trunk or body, as in Fig. 1. Pl. VIII. There the circumference of the wounds isas large as to require feveral grafts which cannot firmly unite and clafp over the ftumps, and confequently thefe wounds lay a foundation for after- decay. If that were not the cafe, yet it fo reduces the fize of the tree, that it could not recover its former ftate in many years, and it is dubious if it ever would; whereas, by the method of extreme grafting, as Fig. 3, the tree will be larger, in three or four years, than before os operdeiee was performed. | For all the large branches remaining, the tree has nothing to make but fruit bearing wood ; and from the beautiful verdure it foon acquires, and the fymmetry of the tree, no argument is neeeffary to enferce the praétice. Fig. 2 was my firft experiment about eight years fince. The error of No, I was there a little amended, and gave me the idea of engrafting at the extremity. Permit me to remark, _ that thofe done in my orchards, on the plan of Fig. 2, did . not, neither were they able to bear fo many apples laft feafon, which was a bearing year, as thofe on the plan of Fig. 3 * This thought fhould be kept in fufpence, as ten years hence it may appear otherwife. However, they will be valuable trees, and highly profitable, as will any other brought under the fare oo which 128 BRANCH GRAFTING. which produced me about two bufhels each tree of the fineft fruit I had in my orchards, from the third fummer’s wood only. Some engrafted with Ribfton pippins were beautiful. Approbation of | Mr. Bucknall vifited me this fummer for the exprefs purpofe, Mr. Bucknalle of feeing my trees; and he fays the manner of conduéting the — fyftem is the happieft that ever was conceived. For when a tree has done its beft, and has continued to extreme oldage, juft difpofed to fall into diffplution, as alfo when this is the cafe with trees in a ftagnated and barren ftate, they are thus renovated, and may, with; the greateft probability, continue valuable for fifty years to come. Ineed not fay, do not make the attempt when the energy of growth is over; that will eafily be feen by the body and arms, but more particularly from the fize, figure, fhape, and colour of the leaves, which give the proper indication of health or decay in vegetation. Should the Society defire it, feveral gentlemen refident here, will gladly fend up certificates to confirm the ftatee ments. I remain, Srr, Your moft obedient fervant, W. FAIRMAN, Millers-Houfe near Sittingbourn, Kent, Feb. 9, 1802. CEMENT FOR ENGKAFTING. Cement for § One pound of pitch engraftinge © One do.... rofin To be boiled up together, but. Half do... . beefwax not to be ufed till you can bear Qtr. do.... hogflard your finger in it. Qir. do... .. turpentine SIR, Teftimonial of “THIS is to certify to the Society for the Encouragement of Bi. Bucknall, Arts, &c. that William Fairman, of Millers-Houfe, Lynfted, Efq. has long been a fteady and zealous promoter of the im-< provement of the ftandard fruits of the country ; and that he planted one entire orchard, of fixteen acres, ten years ago. The fyftem of extreme-branch grafting, now intkoduced to the public, he has had in contemplation full eight years, though not in its prefent ftyle of fuccefs and elegance; for he has been improving. In thofe operated upon within the laft | thre BRANCH GRAFTING. | 129 three or four years he has been wonderfully fuccefsful, and I am happy in an opportunity of adding my teftimony to the advantages refulting from this methad of renovating old fruite trees. An idea equal to the prefent fyftem could not have fallen into better hands than thofe of Mr. Fairman. He is bleffed with a good foil, cultivates the land well, and fteadily attends to improvement; The gentlemen of the committee, by looking at the three little fketches of drawings which reprefent the three trees, will fee that Fig. 1 is fo amputated, as not likely to continue in health, foas again to form a good tree; and that Fig. 2 will be many years before, if ever it does. But there are now many fine large trees in the ftate of Fig. 3, which have been engrafted but three or four years, and yet, ~ as far as ftru€ture goes, are complete already, and in two years much fine fruit may be expeéted. The fyftem is as follows: Make the trees perfeétly clean, and keep them as uniformly large as is convenient. In autumn, 1801, I fpent fome days at Lynfted, and feveral times walked over the plantations with Mr. Fairman, and was very much pleafed with their appearance, I remain, Srr, Your obedient Servant, THOMAS SKIP DYOT BUCKNALL, February 22, 1802. Reference to the Engraving of Mr. Fatrman’s Method of — Reference to'thé Extreme-Branch Grafting; Plate VU. Fig. 1, 2, 3, 4. a Figure 1. difplays the old pra@tice, commonly called clefts grafting. . Fig. 2. Improved experiment on Fig. 1, by engrafting higher up the tree. Fig. 3. Shows the method of extreme-branch grafting, rea commended from experience, by Mr. Fairman. Two grafis or fcions are there placed at the extremity of each branch ; befides which, additional grafis are inferted in the fides of the branches; as, at AAAAAA, or where they are wanted to form the tree into a handfome fhape. Fig. 4, Shows upon a larger feale than the former figures the method of applying the grafts at the extremity of the _ branches, and retaining them by the bafs-mat bandage and cement. Vor. Vi—Octoser, 1803, K Obfervations 13e Unguentum nutritum. The mixture of oil, vinegar, and litharge. Requires car= bonic acid, #o convert the litharge into caibonate, and thicken the oil. Too much vine- gar will pre vent the com- bination. ' Dhe formula of the French pharmacupeia the beft. Litharge com- pletely foluble in acetous acid, but not in com-~ mon vinegar. The refiduum of the latter. FHARMACEUTICAL PREPARATIONS. XIV. Objercatious on feveral Pharmaceutical Preparations, by Crrs. STEINACHER, Druggift at Paris. Abridged by Citizen PARMENTIER*®, Unguentum Nutritum. Citizen Dubree, an eminent druggift at Rouen, has lately prefented a formula for unguentum nutritum, to the Pharmaceutical Society. As apothecaries zealous for the per= feétion of their art, have propofed improvements in the pre~ paration of this ointment at different periods, I have thought that an objeét to which the attention of praétitioners has been called from time to time, notwithftanding it is apparently ob- folete, deferved a frefh examination +. When oil, vinegar, and litharge are to be mixed together into a homogeneous mafs, alittle IMharge mutt be diffolved in acetous acid t, and a fufficient quantity of carbonic acid muft he introduced, 1{t, to convert the greater part of the litharge into white carbonate, which remains diffufed through the oil; Qdly, to thicken the oleous mixture, an effeét analogous to the thickening of foups by the carbonic acid, with which we were made acquainted by Pelletier. If a fufficient quantity of vinegar to form a faturated faline compound be employed, the mixture will never combine perfe@tly. This theory, founded on experiment, brings us back to the prefcribed formula, as the beft ihat can be adopted, that which preduces an ointment, the moft bulky, the lighteft, and the moft cooling to the part * Annales de Chimie, XLVII. 97. (No. 139.) + Dr. Aikin, the learned editor of Lewis’s Materia Medica, fays; “* The unguentum nutritum, made without heat, though now expunged from our difpenfatories, is much the beft of the ointments prepared from lead, and a very excellent application in many cafes. It fhould not be long kept, but made frefh as wanted.” H. t Experience has taught me, that levigated litharge is completely foluble in a fufficient quantity of acetous acid, but that the final re~ ‘fiduum of its folution in common vinegar, which has been fuppofed to be fuperoxided lead, contains only tartrite and malat of lead, with a great deal of extraétive matter, which form a pafte with a remnant of the litharge reduced toward the metallic ftate- affected, PHARMACEUTICAL PREPARATIONS. 131 affééted. It fucceeds very well, when the operator is endued with patience, and worksina cold place. It may be abridged The procefs may however, if, according to the excellent advice of Baumé, we ae eh i employ coagulated oil of olives, by which the furfaces of con- gulated oils taét are increafed, and the introdu@tion of the air is facilitated. One important faét with refpeét to keeping the preparation is, Warmth fpoils that at the temperature of 15° or 16°, at which moft kinds '* of fermentation take place, a portion of the carbonic acid is extricated, and leaves expofed an oxide at +25, which becomes again yellow. It requires a temperature of 10° to preferve But it will keep its white colour unaltered. sinless Citizen Dubree, and Citizen Granet before him, propofed ne ee of to expedite the preparation by adding hog’s lard; but I find, a aaie rans _ that this addition diminifhes its bulk and Lets In Germany D: biaaie aN different compofitions are made under the name of nutritum, POTS os as with vinegar of litharge and half its weight of oil of rofes, Germany« which peadune an ointment as white as wax, and of the con- fiftence of aliniment; with vinegar of litharge two parts, and olive oil three parts, itch Giicka a whitifh ointment of a mo- . derate confiftence; with two parts of olive oil, one part of wax, and two parts of vinegar of litharges; which furnifh an Ointment of a firm confiftence, and a waxy whitenefs. But all All thefe fimply thefe compofitions are fimple mixtures, feebly united, by no ™*™*** means refembling the nutritum of the French fhops, and not requiring for thelr formation a mutual reaétion between the dif- ferent particles of the ingredients. Cryftallization of Phofphoric Acid. It is known, that the affinity of phofphoric acid for water Phofphorie acid _ overpowers its force of cryftallization; in faét this falifiant fub- ane aed: ftance appears commonly in the form of a thick oil. I have yet cry ftalliz= lately obferved, however, that time, the grand producer of ble by time. regular cryftallizations, effeéts a fymmetrical combination be- tween its particles. Thad prepared halfa kilogramme of phofphoric acid, accord- ing to the method of Lavoifier; with phofphorus and nitric atid, both of them extremely pure. This acid, freed from nitrous gas, reduced to the confiftence of a thick fyrup, and introduced into a phial with a glafs ftopper, had been ufed at different times in the courfe of a year, without exhibiting any peculiar appearance, The year following I let it remain per-Cryftals formed ‘aaes K 2 feétly in it by repofey 132 PHARMACEUTICAL PREPARATIONS. - feétly at reft in the phial, which was half full, and clofely Thefe cryfials flopped. After this period I found the furface of the fluid eet Mi ese covered with a faline cruft, from which thot downward prif- famine. matic cryftals in fhining laminz, an inch long, and a line broad, diverging from acentre. I will not defcribe their geometrical ftru€ture, for they are extremely thin, and embedded ina fluid too vifcous for me to take them out without breaking. Befides, they are ftill increafing ; laminze rife from the ealtnns of the veflel, which touch the furface of the glafs, and feem pre- paring to intermix with the ramifications that fhoot down from the upper ftratum. The fides of the veffel are the feat of this beautiful cryftallization. The centre remains in part concrete or fluid, whenceit follows, that if a very regular diffipation of the particles of the liquid acid of phofphorus be occafioned by repofe, the fides of the veffel contribute to it in great mea- fure by affording fixed points, to which the pofitions of affinity moft favourable to cryftallization dire& themfelves. Purity of Phofphorus. Charcoalcom- Prouft has informed the public, that, in the diftillation of bines with phof- phofphorus, a combination of this fubftance with the charcoal phorus daring the diftillation, conftantly took place. This important difcovery, extends much farther than its celebrated author has fhewn. Phofphorus pu» Take the moft brilliant and moft tranfparent phofphorus,. caer which has not only been ftrained through chamois leather, ac- method. cording to Woulfe’s method, but has alfo been diffolved feveral Muffin. Pufch- times in nitro-muriatic acid, as done by Count Muffin-Pufchkin, eee or which has been treated with oxigenated muriatic acid, after or Juch’s, the mode of Mr. Juch of Wurkburg ; let it be heated gently ‘fill thewsmarks in a long flender tube; red parts will feparate from it. Puta ig few grains of this phofphorus, which is conceived to be fo pure, ona filver fpoon, and fet fire to it; a red trace will re- main. If the fpoon be heated in the dark, the red trace will be feen ftill to burn, and a coal will remain impregnated with’ phofphoric acid. Heatingwith Mr. Juch has afferted, that his phofphorus is extremely, ee pure, becaufe it no longer becomes black when heated with. proving the pu- cauftic alkali; but it isin fa&t becaufe the phofphure of car- po of phofpho- hone is unalterable by cauftic potath. According to the indifput- able authority of Prouft, this re-agent is incapable of proving Heatedoxige- the purity of phofphorus, I confels, that heated oxigenated nated muriatic muriatie ee rc ee ——t—(CSCt—™S e , PHARMACEUTICAL PREPARATIONS, 133 muriatic acid deftroys part of the carbone of phofphorus, be- acid deftroys caufe the combuftible power of its oxigen increafes in the P@rt of the care ratio of its elafticity ; but it produces this effect only by burn- ing a proportionate quantity of phofphorus. On the contrary, Cold feparates when it is cold, and its oxigen is reduced to its natural degree a of of elafticity, it is far from deftroying the carbone, it feparates rer it in the ftate of black oxide, and converts the phofphorus inte white oxide, while at the fame time, itfelf returns to the ftate of fimple muriatic acid. Ihave obferved this fa@ on a ftick of tranfparent phofphorus, which I kept two years in a bottle filled with pure oxigenated muriatic acid, faturatéed at the tem- perature of 10°. It is impoflible, therefore, ‘to free the phof- Impoffible to phorus entirely of charcoal. They oxide, or are acidified nearly {°° Phof horus e i ee ‘ 4 from charcoa) in proportional quantities ; and though the proportion of char- completely. _ Coal may be diminifhed, the phofphorus always retains fome by Hs power asa whole. In fine, I am obliged to contradi@ the affertion of an illuftrious mafter, Citizen Fourcroy, ‘* that we Miftake of are unacquainted with any dire&t combination between car- Fovrcroys bone and phofphorus, though it probably exifts,” and to cone fider that produét on which chemifts have hitherto beftowed the name of pure phofphorus, as'a kind of gangue, from which Pare phofphorus the radical phofphorus is difengaged to enter into a number of ¥°t bakaowne combinations, without our being capable of obtainmg it in its primitive form, White Oxide of Phofphorus. When phofphorus is heated in a very long and very Mode of cin- flender glafs tube, in a fand-heat of 100° of the decimal ther- ae ona mometer, it is covered with a mild light, and exhales a white white oxide at a vapour, which condenfes in the upper part of the tube, while, ™#!mum. at the fame time, part of the phofphorus, with excefs of carbone, feparates with its red colour. This white vapour, which has acquired for its formation a flight combuftion, is a white oxide of phofphorus ata minimum. The following are fome of its properties. It is flocculent, poffeffed of cohefion, some of its pros and occupies four times the {pace of the phofphorus employ ei perties. in the experiment. When it is dry, it does not redden lit- mus paper. It contains caloric, and inflames on the conta¢t of combuftible fubflances. It powerfully attraéts the moifture of the air, and is rapidly converted into phofphorus acid. It White oxide of differs greatly from the white oxide of phofphorus made Fe a ‘i Bile 1 134 SCIENTIFIC NEMS. Its properties, the long a€tion of water, or cold oxigenated muriatic acid. This appears friable and pulverulent. It has loft almoft all its Jatent heat. It is very little inflammable, and does not attract the moifture of the air. It is acidifiable only by the intimate action of an oxigen that contains caloric highly con- denfed, as that of the nitric acid. Ina word, it is phofphorus at a maximum of oxidation. Regular Cryfiallization of Effential Oil of Rofes. Regular cryftal- Citizen Steinacher has lately obferved this with atten- eas oilof ‘tion, He mixed eight kilogrammes of the magna of da- mafk rofes (rofés pales) with {ome parts of water, according to the procefs of Cit. Demachy; and after a day’s macera- tion he drew off by diftillation fixteen kilogrammes of water. This was immediately poured into a large glafs jar, which was covered with a cloth, and left at reft. In twenty-four hours he found the furface of the water covered with an iridefcent Refembles the pellicle, interfperfed with little hexhaedrons, very much re- cryftalsof fnow, fembling the cryfials of {now, which the illuftrious Cit. Mongé has defcribed. He informs us, that a flight fhake is and requires ab- fufficient to tear the cryftalline gauze, and reduce it to that folute repofes irregular form of whitifh fcales or lamin, which the oil of rofes commonly aflumes. ——_—_—_—_$_ =_[_[_[_$_=====—[—[—[—[—[—=&=£_=[—[F—[—[—*—T———————[——————SSS>SS— SCIENTIFIC NEWS. Extra& of a Letter from Dr. Scuaus to Mr, Parkinson, dated Caffel, july 2, 1803. I AM bufily employed in the analyfis of various minerals, © the refults of which I fhall communicate to you in my next. I have noticed among other things alfo, that the metal called Tungften not tungften (Wolfram by the Germans) can only be obtained at co the higheft degree of de-oxidation, and that this metal does not belong to the clafs of acidifiable metals ; for tungflen cannot be oxidized by means of common proceffes of oxida-. New method of yen. : obtaining pure 1 have difcovered a new method of obtaining pruffic acid, in pruflic acid. a ftate of abfolute purity. This procefs confifts in pouring upon one part of pruffian blue, half a part of fulphuric acid, diluted 3 with SCIENTIFIC NEWS. ; 138 with an equal quantity of water, and fubfequent diftillation, The pruffic acid paffes over in the alcohol; its odour greatly refembles the water of the lauro cerafus. It is a deadly poifon to animals. Perhaps thefe notices ee intereft the London chemifts, &c. &e. Annotation by the Tranflator, The following method of obtaining tungften, I believe has Richter’s_ not been made known in this country. It is recommended by opamp rom Richter * a German chemift.—F. A. he SE Let equal parts of tungften oxide (tungftic acid) and dried hlood be expofed for fome time to a red-heat in a crucible ; pafs the black powder which is formed into another findttet crucible, and expofe it again to a violent heat ina forge, for at leaft an hour. Tungften will then be found, according ta this chemift, in its metallic ftate in the crucible. See Meteoric Stones, C. BIOT, member of the National Inftitute, in a letter to the Extraordinary French Minifter of the Interior, dated July 20, 1803, gives a Aideos or til ‘detailed account of his inquiries, &c. refpe@ting a fire ball in France. which exploded in the neighbourhood of Laigle. The memoir will be feparately printed. On Tuefday, April 26; 1802, about one in the afternoon, the weather being ferene, there was obferved from Caen, Pont-Audemer, ie the environs of Alencon, Falaile, and Verneuil, a fiery globe of a very brilliant {plendour, which moved in the atmofphere with great rapidity.” Some moments afier there was heard at Laigle, and in the environs of that city in the extent of more than thirty leagues in every dire¢tion, a violent explofion, which lafted five or fix minutes. At firft there were three or four reports like thofe of a cannon, followed by akind of difcharge which refembled a firing of ‘mufketry ; after which there was heard a dreadful rumbling, like the beating of a drum. The air was calm and the fky- ferene, except a few clouds, fuch as are frequently obferved. * Richter ueber die neuen gegenftande der Chimie, Part I. p. 49. Nu ' : , - A The 13¢ SCIENTIFIC NEWS. The noife proceeded from a {mall cloud which had a: reét~ angular form, the largeft fide being in a direétion from eaft to weft. It appeared motionlefs all the time that the phenome~ non lafted. But the vapour of which it was compofed was projeGted momentarily from the different fides by the effeét of the fucceffive explofions. This cloud was about half a league to the north-north-eaft of the town of Laigle; it was at a great elevation in the atmofphere, for the inhabitants of two hamlets a league diftant from each other faw it at the fame time above their heads. In the whole canton over which this cloud hovered, a hiffing noife like that of a ftone difcharged from a fling was heard, and a multitude of mineral maffes, exaétly fimilar to thofe diftinguithed by the name of meteoric tones, were feen to fall at the fame time. The diftriét in which the ftones fell forms an n elliptical extent of about two leagues and a half in length and nearly one in. breadth, the greateft dimenfion being in a dire@tion from fouth-eaft to north-weft, forming-a declination of about 22°. This dire@ion which the meteor muft have followed is exadly that of the magnetic meridian; which is a remarkable refult. The largeft of thefe ftones fell at the fouth-eaft extremity of the large axis of the ellipfe; the middle-fized ones fell in the centre, and the fmalleft at the other extremity. It thereby appears that the largeft fell firft, as might naturally be fup- pofed. The largeft of all thofe which fell weigh 172 pounds. The {malleft he faw weighed about two gros, which is the thous fandth part of the former. The number that fell is certainly. above two or three thoufand. They were friable fome days after their fall, and fmelled ftrongly of fulphur. Their prefent hardnefs was acquired gradually. (ee gee: of a Memoir on the Febrifuge Principle of Cinchona, by Crt. Securn *, ~ ‘THE objeét propofed to himfelf by the author in the tafk he undertook was, to point out the means of knowing with certainty the. true febrifuge principle of cinchona, to dif- tinguith the fpecies that contain it from thofe that da not, and’ laftly to appreciate its quantity and quality. * Bulletin des Sciences, No» 7% : Hitherto. SCIENTIFIC NEWS. 137 Hitherto the fight and tafte have been the only tefts of the Sight and tate prefumable qualities of the peruvian bark of the thops; but as nae Gene thefe bave no precife ftandard, and are inapplicable: to goodnefsof bark. powdered bark, they-very imperfe@tly indicate the prefence of the febrifuge principle. It was of importance, therefore, to fubftitute to thefe means, little better than illufory, others not only capable of calculation, but likewife invariable. Che- mical re-agents alone can anfwer thefe ends, In. confequence Cit. Seguin began by ifolating the refpe€tive properties of all medicinal fubftances, and he examined the action they exert on all other chemical fubftances. Thefe refearches led him to develope very decifive chara€ters The febrifuge eftics in the febrifuge principle of cinchona; which place it rie. ina perfeétly diftinét clafs. The following are its chara€ters. It precipitates the folution of ian, but not the folutions of Its charaéters. gelatine and fulphate of iron. When cinchona has not all thefe charaéters, it is a proof that it is mixed with fomething elfey or that it does not contain the febrifuge principle. The author has fubje@ed to this analyfis all the known Various fpeci- fpecies of cinchona, found among all the druggifts and apothe- eee caries of Paris and Verfailles, and conftantly obtained the tett, fame refults. Unfortunately thefe refearches have fhown, that but an Ba ee infinitely {mall quantity of good, unmixed cinchona, is ta be good is to be procured in the fhops; the greater part being either deftitute Sy in the of the febrifuge principle, or mixed, or of a very inferior on quality, though containing no mixture. } _ Thefe refults are of fo much the greater importance, be- Efficacy of cine caufe the effects.of different kinds of cinchona in fevers are Sapo bee only in proportion to the greater or Jefs quantity of the febri- quantity of fe- fuge principle they contain; and thofe which contain none, as napa lage. . well as all the fubflances that may be mixed with them, are more or lefs injurious to the fyftem. The experiments of Cit, Seguin on. the febrifuge stindiple Defeéts rd ee : of cinchona, having convinced him that moft: of the bark found oe tee . in. the fhops was injurious or inefficacious, becaufe it was {poiled by keeping, adulterated by mixture, or deprived of the febri- fuge principle ; he has endeavoured to obtain a febrifuge prin- ciple always the fame, more efficacious, more certain in its effe&s, more capable of affimilation with our fyftem, and: fo cheap, that there could be no temptation to adulterate it. ii 5 To 138 SCIENTIVEO NEWs. To attain this important objeét, the author has inquired what aS the true caufe of fevers, as of their effects, is; what the nature of the febrifuge principle of chinchoa, and what its aétion on our fyftem. Hehas fubjeéted to the aétion of the re-agents pointed out for the febrifuge principle of cinchona, all chemical and medicinal fubftances ; and affured himfelf, whether fuch of thefe fubftances, as might contain the febrifuge principle, did — not contain, at the fame time,' other fubftances prejudicial to the animal economy. Laftly, he had to cure fevers by the help of thefe remedies, and then confirm this theory by re; peated experiments. Such is the courfe Cit. Seguin has purfued. | The febrifuge The new febrifuge principle, which he propofes to fubftitute Sie. inftead of cinchona, becaufe it unites all the advantages of the bark, without any of its inconveniences, is gelatine in its pure ftate. Advantages this Confidered in a medical, economical, and political view, he over gelatine promifes much greater advantages than bark, in its application to the cure of fevers. It occafions no irritation ; procures quiet fleep and gentle perfpiration ; keeps the belly open, without producing colic or naufea: has no unpleafant flavour; reflores the ftrength, and is digefted even by the weakeft ftomach, that would reject the "bat as foon as ad- miniftered. Difadvantagesof On the other hand, cinchona irritates the fyftem, difturbs bark. the fleep, has a difagreeable tafte, frequently occafions cof- tivenefs, and is very indigettiblas Gomesorive In an economical view, there is ftill greater difference 8 cheapnefs o} dictine, tween cinchona and gelatine; the price of the latter being to that of the former at moft as one to thirty-two Laftly, gelatine is indigenous, cinchona is oes ; and the purchafe of the Jatter requires us to fend abroad a very confi- derable fum of money, which might be kept at home by adopting the ufe of gelatine. Cafes cured by | To this memoir the author has fubjoined thirty-feven cafes, ‘es in which he performed a cure with gelatine, under the eyes of fome refpeétable phyficians, and he has defired a Committee to be appointed, to repeat his experiments, and report ie them. Committee ap- Accordingly Citizen Portal, Defeffarts, Hallé, Fourcroy, pointed to exa- imine its effects, Berthollet, and So bateces been nominated for this gone ‘ eir SCIENTIFIC: NEWS. 139 Their experiments are made at the School of Medicine, in a room. exclufively appropriated to thefe inquiries ; already awhich apgjar to great number of patients have been cured ; and. the Com- (os nae, by mittee will foon make their firft report on thefe cafes. Query by a Correfpondent refpecting the Auguftine Earth, To Mr. NICHOLSON. SIR, WE poffefs many excellent elementary works on Che- Auguftine earth, _mifiry, both original and tranflations, fuch as Thompfon, Aecum, Murray, Henry, Parkinfon, La.Grange, Green, Fourcroy, Jacquin, &c. but in none of thefe authors is men- tioned the method for obtaining the new earth, called Aux gufine; although moft of thefe works have been publifhed a confiderable time after this earth -was made known by the German difcoverer, Profeffor Tromfdorf. .I have alfo made enquiry, concerning this fubjeét, of moft of the public teachers of chemiftry, and other individuals, who ftand high as che- mical philofophers, but in vain ; I will therefore thank you to allow thefe lines a place in your valuable Journal. Perhaps one of your Correfpondents will be kind enough to favour me _ with the procefs for obtaining this earth; for the author of thefe lines cannot find it in the mineral which is faid to con- tain it; having purfued the ufual methods of examining Mis neral fubftances for that purpofe. I am, R “* SIR, Your’s, &c. P. O. Spaniard faid to refit high Degrees of Heat and ftrong chemical Agents, THE prints of Paris, and fome of our own, too implicitly Extraordinary co for fi bited a ft ftory of a Spa- pying them, have for fome time exhibited a ftrange narra- Linciitin totied tive ofa young Spaniard, born at Tolofa, and now 23 years fift heat and cor= of age, of whom it has been very particularly affirmed, ‘Ave acids. That 140 7 SCIENTIFIC NEWS. That though his fkin exhibited no appearance of peculiarity, either natural, or indicating preparation by art, yet without injury, 1. He bathed his feet for fix minutes, and wafhed his. hands. and face in oil heated to 250° of Fahrenheit, which is 38 degrees hotter than boiling water. 2. He did the fame with a folution of fea falt, heated 12 degrees higher. 3. He ftood with his naked feet upon a bar of iron near the welding, or at the white heat ; he held the bar in this Rate in his hands, and rubbed it on the furface of histongue. 5. He wathed his mouth with the firongeft fulphurie and nitric acids, and applied the fame to the other parts of his ikin, with no other effeét than that the nitric acid produced a yellow.tinge ; and 6. he remained a confiderable time in an oven heated to within 18 degrees of the boiling water point. Though our reafoning from analogy in matters of experi- ment, is liable to miflead, as well by infufing too much doubt as too much confidence, yet I fhould have paffed over this tale without notice, if I hed not heard of it from very refpe@- able correfpondents. I fuppofe there may be fomething ex< traordinary in the degree of infenfibility of the fubjeét in quel. tion, as the Inftitute has paid attention to him ; but I under- ftand that the ftory is now told with great abatements. Citizen Pinel, a man of information, and well known as an accurate _ obferver, is commiflioned to report upon the fame; and } have Flavour of malt fpirits amended Lute, eggs and chalk, or flaked dimes uo doubt but his account will fhew how much eafier it is for men to tell falfehoods than to reverfe the courfe of nature. ~ Method of giving Malt Spirits the Flavour of Brandy.* INTO a quart of malt fpirits put three ounces and a half of finely powdered charcoal, and four ounces anda half of ground rice. Let. thefe ingredients remain during fifteen, days, only obferving to ftir them often: at the expiration of this time, let the liquor be ftrained, and it will be found to be much improved. Preparation of a Lute proper for Chemical Operations, By C. Paysse, Profefor of Chemifiry.t | IN the preparation of the oxigenated muriatic acid in the large way, the neceffity I found for a lute, which, to the ad-. * From the Bibliotheque Phyfique Economique, No. 10. An. XI. + From the Annales de Chimie, No, 137. An, XI, vantage SCIENTIFIC NEWS, vantage of being cheap, fhould add thofe of being eafily pre« pared ; of refifting the a@tion of the deftruétive. vapour of the acid, as well as the ftrong heat which the luted part is often required to bear; which fhould be eafy of application, and im an uniform manner, and not harden too quick! y 3 obliged me to make fome experiments on the fubje@, the refult of which have been very fatisfa€tory. After making a great number of mixtures. with different fubftances, I made choice of the following, which produced me a homogeneous compofition, drying as flowly as could be defired, extremely hard; when dry, of a very compa@ texture; and, in fhort, poffefling all the properties I had defired, ; Take the white of two eggs, with their-yolks, and of pow- dered carbonate of lime, or of quick lime well flaked in the air, about half the weight of the eggs; fpread it on a cloth, and apply it as a lute. NOTE. THIS lute, the compofition of which is very fmple, pof- feffes a degree of elafticity, when dry; I have formed veflels of it, which are impermeable to water, and fufceptible of being polifhed on the wheel. This compofition refembles the fubRance of which the pipes, called Meerfhaum, are made. Two new Quadrupeds.* Two living Quadrupeds have lately been received at the : Mufeum of Natural Hiftory at Paris, which are entirely un- _ known among naturalifts, and were brought to Europe by Captain Baudin. Profeffor Geoffroy (of Egypt) who has in- ferted a defcription of them in the annals of the Mufeum, calls them Fafcolomes. They come from the wettern coaft of New Holland; their fur promifes to be of fome ufe; and, “according to the opinion of Captain Hamelin and his fuite, their flefh is very excellent food. They are particularly inte- refting to naturalifts from the fingularity of their organization. In the form of the head, the number, arrangement, and na- ture of the teeth, and the form of the fore feet with which * Decade Philof. No. 51, An, XT, tthey 141 Two new Qua- drupeds from New Holland, 142 : fenee of iron m ruft. SCIENTIFIC NEWS. they butrow in the earth, they refemble the marmot ; but they differ from them, by the female having a pouch beneath the belly, and by the whole ftruéture of the organs of gene- ration, in which they are fimilar to the farique of Buffon. The form of the hinder foot is the fame as in that animal with a pouch; the thumb being diftin@ from the other fingers; and without a nail: the tail is fo fhort, that it remains hid be- below the hair, which is brown, bufhy, and very long. The Fafcolomes of the Menagerie are yet young, but are already larger than rabbits. Their temper is admirable ;: they may be handled, or removed, without fhewing any fymptoms of fear; anger, or uneafinefs ; their movements are heavy and clumfy ; they live under ground, fleep during the day, and go in fearch of food at mght. In ‘general they poflefs but little energy or aftivity ; they fcratch themfelves like the monkey, and they may be fed with bread, milk, roots, and every fort of herbage. Prefervation of Iron from Ruft. CIT. Conté has adopted a method, which he finds effe@tual, for preventing the oxidation of iron and fteel ; or, -in popular terms, to prevent iron and fteel from rufting. It contifts in mixing with fat oil varnifh, at leaft half, or at moft four-fifths of its quantity of highly reétified {pirits of tur pentine. This varnifh muft be lightly and evenly applied with a fponge ; after which the article is left to dry in fome fituation not expofed to duft. He affirms, that articles thus varnifhed retain their metallic luftre, and do not contra€ any {pots of ruft. This varnifh may alfo be applied to copper, of which it preferves the polifh, and heightens the colour. I¢ may be employed with particular advantage to preferve philo- fophical inftruments from any change, in experiments where, by being placed in conta& with water, they are fubje& to lofe that polifh and precifion of form which conftituted part of their value. ACCOUNT AGGOUNT OF NEW BOOKS:;* | ACCOUNT OF NEW BOOKS. Philofophical Tranfa@ions of the Royal Society of London, for the Year 1803. Part I. Tue Contents of this Part are, 1. The Bakerian Le@ure, Obfervations on the Quantity of horizontal Refra€tion; with a Method of meafuring the Dip at Sea. By William Hyde Wollafton, M.D. F.R.S. 2. A Chemical Analyfis of fome Calamines. By James Smithfon, Efq. F.R.S. 3. Experi- ments on the Quantity of Gafes abforbed by Water at different Temperatures and under different Preffures. By Mr. William Henry. 4. Experiments and Obfervations on the various Alloys, on the Specific Gravity, and on the comparative Wear of Gold, » Being the Subftance of a Report made to the Right Honourable the Lords of the Committee of the Privy Council, appointed to take into Confideration the State of the Coin of this Kingdom, and the prefent Eftablifhment and Conftitution of His Majefty’s Mint. By Charles Hatchett, Efg. F.R.S. 5. Obfervations on the Chemical Nature of the Humour of the Eye. By Richard Chenevix, Efq. F.R.S. and M.R.I.A. 6. An Account of fome Stones faid to have fallen on the Earth in France, and a Lump of Native Iron faid to have fallen in In- dia. By the Right Honourable Charles Greville, F. R.S. 7. Obfervations on the Struéture of the Tongue, illuftrated by Cafes in which a portion of that Organ has been removed by Ligature. By Everard Home, Efq. F.R.S. 8. Obferva- tions on the Tranfit of Mercury over the Difk of the Sun; to which is added an Inveftigation of the Caufes which often prevent the proper A@tion of Mirrors. By William Herfchell, LL. D.F. R.S.&c. 9. An Account of fome Experiments and Obfervations on the Conftituent Parts of certain Aftringent Vegetables; and on their Operation in Tanning. By Hum- phry Davy, Efq. Profeffor of Chemiftry in the Royal Infti- _ tution. 10. Appendix to Mr. William Henry’s Paper, on the — Quantity of Gafes abforbed by Water, at different Tempera- tures, and under different Preffures.* we APPENDIX. Meteorological Journal kept at the Apartments of the Royal Society, by Order of the Prefident and Council. * Our Readers will obferve, that we have as ufual, reprinted in - our Journal moft of thefe valuable Papers, An 143 144 ACCOUNT OF NEW BOOKS. An Effay on the Law of Patents for new Inventions ; 40 which are prefixed Two Chapters on the general Hiftory of Monopoliess and on their Introduétion and Progrefs in England, to the Timé of the Inter-regnum: with an Appendix containing Copies of the Caveat, Petiteon, Oath, and other Formula, with an ar-~ ranged Catalogue of all the Patents-granted from tlie \ft of Ja- nuary 1800, to the prefent Time. By Joun Dyer Couture, 1803. . Longman and Rees, Royal 8vo. One of the moft obvious expedients for taxing the induftry of man in focial life, but at the fame time one of the moft pers nicious, confifts in monopolies, Accordingly we find in all governments that this refource is more or lefs adopted, and _ trades, manufactures, and various operations, become confined, to the excutive power, or what is worfe, to the private fas vourites of men of influence. A long feries of years have elapfed fince this nuifance was abolifhed in our country, by the ftatute of James, and the monopolies that yet remain, are under the dire@ fanétion of law, and fo few, that a common obferver would be difpofed to fay we have none. A clafs of monopolies which has conftituted the fubjeét of a claufe of exception in that aét, confifts in the fole working and making of new manufaétures for a limited time under royal. grant, to the firft and true inventor thereof. It has beena fubjeét of difcuffion whether even this exclufive privilege which is often made the inftrument of public deception, and fome- times of oppreffion by wealthy Individuals to crufh the induftry of ingenious men by expenfive legal proceffes under letters patent, for objeéts of public poffeffion; it has often been dif-. puted whethker this exclufive privilege be a benefit or an evil. The faéts I think are, that many private fortunes are loft, in {upporting pretended inventors, or in bringing real ones into effect, and that our arts, trade and fciences are greatly bene- fitted by this laft operation ;— The fubjeét of patents and monopolies in general is there- fore of great intereft and praQical importance, and I have no doubt the public will receive this compendium as a valuable addition to their means of information refpe@ting them. A JOURNAL NATURAL PHILOSOPHY, CHEMISTRY, AND DE SA Ros: NOVEMBER, 1803. ARTICLE. L Experiments and Obyjercations on the various Alloys, on the Specific Gravity, and on the comparative Wear of Gold. Abftraéted Jrom the Memoir of Cuarues Hatcuert, Ey. F.R.S. nthe Philof. Tranf: for 1803. (Concluded from Vol. V. Page 303 of our Journal.) Esaperimen i. ae pieces of ftandard gold were firft ae a and Lofs of ftandard were placed fo that fix were ale to fix. gold by friétion, The brafs frame, in which each upper piece was, fixed, ~ weighed 1604 grains; and it was found neceflary to. add to each a weight of lead, equal to 19825 grains; fo that the pieces were rubbed againft each other under the preffure of 19825-+1604=21429 grains = 3 lb. 80z. 12dts. 21 grs * * This weight was not employed till repeated trials had proved the extreme difficulty, and almoft impoffibility, of producing any perceptible effeét with lefs, in a moderate period of time; and, even with this weight, the experiments were found te be exceed- ingly tedious. The only evil which refulted from fuch a preffure ' was, that the comparative wear of the fine gold appeared much more confiderable than would have been the cafe, if a {mall weight could have been employed; fome obfervations will therefore be found in the fubfequent pages, which point out the neceflity of making an allowance for this circumftance. » Vor. VI.—NovemBer, 1803, L The 146 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD, The machine was then put in motion, until the index fhowed that 286690 revolutions had been performed ; and, as a double © crank aéted during each revolution, the pieces were rubbed againft each other alternately, in oppofite direétions, 573380 times, being twice the number of the revolutions. The twelve pieces of ftandard gold, being taken out, were : weighed, and were found to have loft 8,60 grs. Experiment ee Of gold alloyed | Twelve pieces of gold combined with an equal proportion with an unequalof copper, and without any impreffion, loft 103,11 grs. in weight of copper. Epes ge Se 4 4 riabteieh 70640 revolutions. Experiment Ill. Of fine copper, Mrwelve fimilar pieces of fine copper, loft 174,80 grs in 22200 revolutions. Hence it appears, that ftandard gold lofes lefs by friétion than gold much debafed by copper, and this lefs than copper alone. Gold alloyed The next feries of experiments was made with gold dif- Aa la ae ferently alloyed; when gold 1. made ftandard by copper, 2. aS ae reduced to 18 carats by copper, 3. made ftandard by copper and filver, 4. made ftandard by filver, 5. of 23 car. 3% grs. fine, 6. made ftandard by tin and copper, 7. made ftandard by iron a copper, 8. alloyed with an equal quantity of copper, was found to have loft in the following proportions, in the order in which they have been enumerated. Ogrs. Ogrs. 0,10 grs. 0,10grs. 4,20 grs. 15,30grs. 21,60 grs. 65,78 grs. The wear of the pieces alioeed with equal parts of gold and copper, and with iron and copper, was fo rapid, that they were obliged to be taken out of the machine after 105480 revolutions ; and thofe containing tin were worn fo thin in 189000 revolutions, as to require being removed: the reft fuftained 200300 re- volutions, whence their comparative lofs was ftill lefs than as above given. Gold fimilarly This experiment being rite on fmooth, flat pieces, it was Monae repeated with others of fimilar compofition ftamped with the die before defcribed, only omitting the compound of equal parts of gold and copper, and adding pieces of ftandard filver and of fine copper. The number of revolutions were only 20680, and the pieces, taking them in the order already mentioned, now loft refpeétively : 0,60 grs. 4,80 grs. 1,20 grs. 3,58 wT EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 3,50 grs. 4,60 grs. 13,80 grs. 7,60 grs. The ftandard filver loft 3,70 grs. the fine copper 46,30. 147 Standard filver . and fine co »pper - From comparing the effeéts produced with the number of re- raifed furfaces volutions, it is obvious, that much more is loft in the friétion of emboffed furfaces, than of plain. The experiments were afterwards varied by placing pieces of the different compofitions in fuch a manner, that in fome cafes the friétion fhould be between fimilar pieces, in others, between thofe differently alloyed. The refults of all thofe experiments are tabulated, but they would occupy too much room to enter into them minutely; and though, from un- avoidable circumftances, fome little inaccuracies oeca- fionally occurred, they may be concluded, as Mr. H. obferves to prove: ift. That fine sale, or of 23 car. 32 grs. when expofed to friétion againft gold of an equal quality, under the preffure of a confiderable weight, fuffers a very notable lofs; and, al- though various circumftances feemed to indicate, that but little effeét, in refpeét to abrafion, is produced under a lefs weight, yet it muft be remembered, that the firft cafe may occur. * . Moreover, that fine gold, under all circumftances, is more fubje€t to have any raifed parts of its {urface obliterated, than any variety of alloyed gold; not always, nor indeed fo much, * It is proper to remark, that the preceding experiments were made under a much greater weight than can be fuppofed to operate generally during the circulation of money ; and as, by fome pre- vious experiments, a lefs weight was found to produce, during a certain time, little or no effect, it may be fufpeéted, that although, under a greater preffure, fine or very ductile gold fuftains a greater Jofs than fome of thofe which are reduced to ftandard, yet, under a lefs preffure, or fuch as that which moft commonly prevails in the courfe of the ufual wear of coin, the reverfe may probably be the cafe ; for then the fame caufes operate with le{s rapidity, during a long period of time. From many various circumftances, there is reafon therefore to believe, that the wear of coin againft coin of a fimilar quality is, under a fmall or very moderate weight, in the inverfe ratio to the degree of duétility; but this is only to be un- derftood in the abovementioned cafe, of coin rubbed againft coin of equal quality. Leg by lofe moft. Fri€tion be- tween fimilar and diflimilar pieces. Fine gold. Wear of coin in the inverfe ratio of its duce tility. 148 Standard gold. Gold with iron or tine ¥8 carat gold, with copper. Gold much de- bafed with cop- per. Difadvantage of foftnefs in coin. EXPERIMENTS ON VARIOUS ALLOYS OF GOLD, by a@tual abrafion, as. by having the protuberant parts preffed and rubbed into the mafs, in confequence of its extreme foft- nefs and duétility.* 2d. That fine gold, or of 23 car. 32 grs. when rubbed againft the various kinds of alloved gold, always or pong fuffers the greateft comparative lofs. 3d. That gold reduced to 22 carats, or to fanttond by filver, or by filver and copper, or merely by copper, fuffers by friction, under general and fimilar cireumftances, a {maller diminution than the fine gold abovementioned; and, with or without abrafion, the protuberant parts on the furfaces of thefe pieces remain much more permanent, under all circums flances, than thofe of the fine gold. The difference of wear between the three kinds of ftandard gold abovementioned, does not in reality appear to be very confiderable ; but, upon the whole, the preference may be given to gold alloyed with a mixture of filver and copper, or to that which has only copper for the alloy. 4th. That gold made ftandard partly by the addition of iron or tin, fuftains a greater lofs by fri€tion than either of the three kinds of Gamaeed gold above-mentioned. 5th. That gold reduced to 18 carats by copper, is more liable occafionally to wear, in a {mall degree, than the three kinds of ftandard gold which have been lately mentioned, provided that the friétion takes place between pieces of equal quality ; but, in the contrary cafe, the principal lofs always falls on the foft or ftandard gold, when it is oppofed to gold of 18 carats, which is confiderably harder. 6th. That gold more debafed than that of 18 carats, fuch as gold alloyed with an equal proportion of copper, fuffers very confiderably msore than any of the kinds hitherto mentioned, provided that the pieces are of the fame quality ; but, on the contrary, fine and ftandard gold experience a very great lofs, when expofed to the aétion of this debafed gold, while the lofs of the latter is comparatively much lefs. * This is, however, of much confequence; for, although coin may not fuffer by actual abrafion, yet, if the impreffion made upon it can fo foon be deftroyed, it follows of courfe, that the pieces be~ come (although ftill allowed to be current) no better than mere blanks, or fragments of a bar or ingot. 7th EXPERIMENTS ON VARIOUS ALLOYS OE GOLD, 149 7th. That the wear of ftandard filver appears to be nearly Standard filver. equal with that of fine gold; but more than that of gold _ made ftandard by filver or by copper, and lefs than that of gold much debafed by copper. 8th. That, as gold which is not inferior to ftandard wears , in general lefs than ftandard filver, fo does this laft fuffer much lefs than copper, The lofs fuftained by copper, when rubbed againft copper, Copper: is infinitely more than that of the former metals; and, when thefe are expofed to the a@tion of copper, they, as well as the Copper, fuffer a very confiderable lofs. This appears from the general refults of thefe experiments, which prove, that pieces of metal which are the moft fubjeét to wear,, are thofe which produce the greateft lofs upon other pieces of metal, when rubbed againft them; and it is remarkable, that in fuch a cafe, the lofs does not always fall on one in preference to the other ; fo that the wear can only be confidered in the aggregate, although one of the pieces may be regarded as the principal caufe, In order, however, to illuftrate the refults of the preceding experiments, as far as they concern the fofter and harder kinds of ftandard gold, and to afcertain more fully the com- parative wear of flat and fmooth furfaces with that of {uch as were partl; protuberant, an experiment was made, with two kinds of ftandard gold: 1f. Gold made ftandard by fine Gold made Swedifh copper, which was very du@tile; and, 2d. Gold shah dl che made ftandard by a mixture of fine Swedifh copper and dollar copper. _ copper. This was as brittle as was compatible with rolling _ and ftamping; and was prepared by melting gold made _ ftandard by fine Swedifh copper, with an equal quantity of _ gold rendered brittle by the ftandard proportion of Swedith ' dollar copper, which was mentioned in the firft feGion of _ this paper. > S «© It may here be obferved, that a diftinion muft be made Diftin@tion be- _ between hard and brittle metal. If a metal is difpofed to en ate crack when rolled, without requiring any extraordinary force _ to enable it to pafs the rollers, then it may be regarded as brittle; but, if it requires an extraordinary force to make it : pals the rollers, and is not difpofed to crack, then it may be _ confidered as hard, , This 150 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. This experiment proves, Very duttile 1ft. That very duétile ftandard gold, when expofed to the’ eae 80l4 frition of gold of a fimilar quality, fuffers lefs by abrafion than gold which is comparatively brittle, or harder, and which is fubje€ted to friétion under the fame circumftances. 2d. That when foft gold and brittle or hard gold rub again{t each other, the greateft lofs is fuftained by the foft gold. And, 3d. That pieces which have raifed or emboffed furfaces, fuffer a greater lofs, under every circumftance, than thofe which are fmooth and flat. ; Coin rubbing | The whole of the foregoing experiments were made with nae ee the machine called No. 1; and, as the fri€tion was conti- lation, lofes but nued, in each experiment, during many days, with a prefiure Berle. upon each couple of pieces equal to 3 lbs. 80z, 12 dts. and 21 grs., and as (confidering the feverity of fuch a trial) the lofs fuftained by the pieces, feparately or colleétively, was not very confiderable, it may with reafon be inferred, that ftandard gold does not eafily fuffer abrafion by the friétion of metal againft metal, or of coin againft coin, efpecially under . the circumftances which commonly prevail during the circula- tion of money. In the machine No. 1, the pieces of gold were oppofed face to face ; it now therefore appeared proper, that the faéts thus afcertained concerning the wear of gold, of different degrees of duétility, fhould be farther examined, and corro- borated by a different methed. To effe& this, the fecond of the machines before defcribed, was employed. 4 Emperimicn Two hundred pieces of gold, of five different qualities, with machine, x ‘ : i RG e: were employed in this experiment; twenty pieces of each ‘kind were plain and fmooth, the others were ftamped with the die already mentioned. The two hundred pieces were mingled, and were enclofed within the cubic box. Different quali- The following were the qualities of the gold. 1. Gold of ~ ai plelities thy a 32 grs. 2. Gold made ftandard by filver. 3. Gold made ftandard by filver and copper. 4. Gold made ftandard by fine Swedifh copper. 5. Gold made ftandard by equal parts of fine Swedith copper and dollar copper. Their lofse After 71720 revolutions of this machine, performed in 40 hours, the lofs fuftained was found to be as follows: of No. 1. the EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 151 the unftamped pieces 92,8 grs.. ftamped, 95,6 grs. No. 2 -unftamped, 63,5 grs. ftamped, 60,1 grs. No. 3, unftamped, 12 grs. flamped, 11,7 grs. No.4, unftamped, 18 grs. ftamped, 19,2 grs. No. 5, unftamped, 13 grs. ftamped 12,1 grs. The total weight of the unfiamped pieces, before friGion, was : 13701,3 grs. Their total. lofs, 199,3: the weight of the fiamped, 13679,5; the lofs.198,7 All the pieces appeared to ba fuffered more on the edges Edges worn than on the faces ; and thofe which were ftamped had the im- mot; preffion more or lefs obliterated or flattened, in proportion to their refpeG&ive degree of duétility, or to the lofs which according to the refult of this experiment, they had rela- tively fuftained. The different pieces, after the experiment, had a curious 2 raifed bead appearance ; for, on the edges, which were become round wile ache and polifhed, a fmall regular raifed bead or moulding was formed, which furrounded each face, like a frame; and both the faces con- faces were become more or lefs concave. ad The original diameter of the pieces was alfo diminiflied, The diameter nearly according to their different degrees of duétility, and ac- diminithed. cording to the lofs which they had experienced in confequence of the operation. The meafure of the diameters of the pieces, after the ex- periment, was, Gold 23 car. 3 grs. eight-tenths of an inch and 3 _ Gold alloyed with filver, nine-tenths of an inch. The others varied litle from nine-tenths and =; which was lefs, by about 4, of an inch, than the originai diameter of the pieces; and a was evident, that. the pieces of fine gold, and thofe confifting of gold alloyed with filver, being the moft du@tile, had fuffered the greateft lofs, and were moft diminifhed in diameter. Upon the whole, therefore, this ex- periment appears to corroborate what has been afferted con- cerning the former, viz. that foft or duétile gold fuffers the greateft lofs, when expofed to friction in contaét with gold which is comparatively harder. Thefe experiments for afcer- taining the effects arifing from the fri@tion of coin againft coin being gone through, another feries was commenced with the apparatus, No. 3, by means of which various pieces were ex- Apparatus, pofed to the aétion of certain powders and filings’of metals, No- 3¢ which were feparately fprinkled upon the horizontal table. 7 The 152 Friction of gold by whiting, fand, filings of ftandard gold, and of iron. General refults. Fine gold lofes its impreffion. Very hard gold. improper for coin; Why. EXPERIMENTS ON VARIOUS ALLOYS OF GOLD, The pieces were properly fixed in their refpe€tive fockets © and frames, and were placed fo as to bear upon the table, with or without additional weights. : The table was moved by a wheel and pinion, fo calculated as to avoid too rapid a motion; and the revolutions were de- noted, as in the former experiments, by means of a counter. The table was covered with fine powdered whiting, with fine white writing fand, with filings of gold made ftandard by copper, and laftly filings of iron. The laft three were fixed on the table by means’of a folution of ifinglafs. Geld of dif- ferent kinds as before, ftandard filver, and fine copper, both ftamped and unftamped, were fubjeéted to the different trials. From the whole of the preceding experiments, made with the three different machines, viewed and compared together, the author infers. 1ft. That when equal friction, affifted by a moderate pref- — fure, takes place between pieces of coin of a fimilar quality, abrafion is moft commonly produced in an inverfe ratio to the ductility. * 2d. That the contrary effeét happens, when pieces of dif- ferent qualities rub againft each other ; for then, the more duc- tile metal is worn by that which is harder.* 3d. That earthy powders and metallic filings produce fimilar effeéts, and tend to wear the different kinds of gold in proportion to their refpe€tive degrees of duétility. Fine gold, being extremely foft and duétile, fuftains a con- fiderable lofs, under many of the general circumftances of fri€tion ; and as at all times it appears certain, that the im- preflions which have been ftamped upon it are moft eafily obliterated, even when aétual abrafion does not take place, there is much reafon to conclude, that gold of fuch extreme du@tility is not that which is the moft proper to be formed into coin. But gold of the oppofite quality, or at leaft fo hard as to be juft capable of being rolled and ftamped, feems to be equally improper for the purpofe of coin. For, even fup- * Some experiments made at Paris, in 1790, upon pure and upon alloyed filver are concifely mentioned, the refults of which appear to be nearly the fame as thofe of the prefent experiments upon gold. pofing — _ EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. - pofing that hard gold fuffered, in every cafe, lefs by fri€tion than that which is moderately dutile, (which is not however the fact,) and allowing that ftandard gold may, by a mixed alloy, be rendered as hard as gold reduced by copper to 18 carats, without changing the ftandard proportion of gold, yet it would be very difficult always to make fuch ftandard gold of an uniform degree of hardnefs. Moreover, by fome experiments which Mr. H. purpofely made at the Mint, upon the rolling and ftamping of gold of different qualities, it evidently appeared, that gold equal in hardnefs to that of 18 carats, could not be employed with advantage; for, the additional labour which was required for the rolling and ftamping of this hard gold, the frequent failure in making the impreffion, and the battering and breaking of the dies, fully proved, that the expence and difficulty attending the working of fuch gold, would by no means be compenfated by any fmall degree of durability which it might poffefs over any other. The extremes of duétility and of hardnefs being therefore equally obje@tionable, it follows of courfe, that gold of mo- derate duétility muft be that which is the beft adapted for _ coin; and, as nothing but filver or copper can be employed to alloy gold which 1s intended to be coined, it may be here obferved, that whatever might have been the original motive for introducing the prefent ftandard of 22 carats, yet it ap- pears, from the experiments lately defcribed, that this pro- portion of +. of the above-mentioned metals, is (every cir- cumftance being confidered) the beft, or at leaft as good as any, which could have been chofen. There is, however, fome difference in the quality of gold, when alloyed with the ftandard proportion of filver, of filver and copper, and of copper, which requires to be con- fidered. - Gold alloyed with one-twelfth of filver, is of a fine but pale yellow ; it is very duétile ; it is eafily rolled, and may be ftamped without being annealed ; it confequently does not require to be blanched ; and, after the complete procefs of coining, the furface and every part remains of an uni- form quality, fo that, by wear, it does not appear of different _ colours. - Thefe properties are certainly much to be valued ; but the objections to this kind of ftandard gold are, ift. 153 Gold of mode- rate ductility beft. Gold alloyed with filver 5 its advantages 5 * 154 Its difadvan- tages 5 with equal parts of Gilver and copper 3 its ad- vantages 5 its difadvan- ‘tages: EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. Ift. The additional expence attending the ufe of filver as an alloy. . 2d. Theextreme pale yellow colour. And, 3d. That, from its great du@tility, it is almoft as liable to have the impreflions which have been made upon it obliterated, as thofe which have been made upon fine gold. All things being therefore confidered, gold alloyed only with filver, does not appear to be fo proper for coin as may at firft be imagined. Gold made ftandard by a mixture of equal parts of filver and copper, is not fo foft as gold alloyed only ‘with filver ; neither is it fo pale, for it appears to be lefs removed from the colour of fine gold than either the former or the following metal. i Gold alloyed with filver and copper, when annealed, does not become black, but brown; and this colour is more eafily removed by the blanching liquor, or folution of alum, than when the whole of the alloy confifts of copper. It may alfo be rolled and fiamped with great facility ; and, under many circumftances, it appears to fuffer lefs by fri€tion, than gold alloyed by filver, or by copper alone, But, afler it has been -fubjeéted to the ordinary friétion which muft take place during the circulation of money, it is liable to appear of a deeper colour in thofe parts. which are alloyed with copper alone. prominent, and are confequently the moft expofed to friétion. This defe& arifes from a caufe which will foon be explained, but it cannot be regarded as an objeétion of any weight. The laft kind of ftandard gold which remains to be men- - tioned, is that which is alloyed only by copper. This is of a much deeper colour than thofe which have been hitherto no- ticed, and it is flightly harder than either of them ; but ne- verthelefs it is very duétile, provided that the copper be pure. It requires to be annealed, and then becomés nearly or quite black: which colour is not fo eafily removed by the blanch- ing liquor, as that.which is produced by the procefs of annealing, upon gold alloyed with a mixture of filver and copper. | It fuffers lefs by many of the varieties of fri€tion, than gold ‘which is alloyed with filver ; but, in fome'cafes, it feems to wear rather more than gold alloyed with filver and copper ; the difference is not however very confiderable. This EXPERIMENTS ON VARIOUS* ALLOYS @F GOLD. 155 This fort of ftandard gold, as well as that which is alloyed with filver and copper, appears commonly, after a certain de- '. gree of wear, of a coppery colour, more or lefs deep, in thofe parts which are the moft prominent; and, when coin thus alloyed exhibits fuch an appearance, it is frequently and vul- garly faid to have been in. contact with copper money ; and. fometimes guineas having this appearance have been refufed, upon the fuppofition that they were debafed. But the real fact is, that when copper conftitutes part or the whole of the alloy, it becomes oxidized or calcined upon;the furface of the blanks, by the procefs of annealing ; and the blackith cruft of -copper, in this ftate, muft then be removed by the folution of alum, called the blanching liquor. Now it is evident, that after this operation, the furfaces of the blanks or un- unftamped pieces, can no longer be regarded as ftandard gold. For, if copper alone forms the alloy, it muft be diffolved and -feparated from the furface of each piece of coin; and the fame effect muft alfo take place, with refpeét to the copper, in the alloy formed of copper and filver.. So that, in the firft cafe, each piece, when blanched, will confift of gold made ftandard by copper, covered with a thin coat of fine gold; and, in the fecond cafe, each piece will be compofed of gold made ftandard by filver and copper, coated with gold alloyed with 4. of filver, or with half of the ftandard pro- portion of alloy, fuppofing the filver and copper to have been in equal quantities. As, therefore, the ftandard gold of which the pieces confift is always, more or lefs, of a deeper colour than the coating or film of the finer gold which covers each piece, it muft be evident, that when this coating has been rubbed and removed from the raifed or pro- minent parts, thefe will appear of a very different and deeper. colour than the flat part or ground of the coin. The reafon thereforé is fufficiently apparent, why gold which is alloyed with filver only, cannot be liable to this blemifh. Upon a comparifon of the different qualities of the three Comparifon of — kinds of ftandard gold which have been lately mentioned, it ee appears, (ftri€tly fpeaking,) that gold made ftandard by filver and copper is rather to be preferred for coin; but, as gold’ made ftandard by copper alone is not very much ins ferior in its general properties, it may be queftioned, whe- ther. the few advantages which are thus gained, will com- penfate 156 Extraordinary lofs fuftained by our gold coin not imputable to fair Wear. EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. penfate the additional expence of the filver required for half of the alloy; and, indeed, any extraordinary addition of filver appears to be the lefs neceflary, as there is commonly fome filver in the gold which is fent to the: Mint, which, being reckoned as part of the alloy, contributes to produce thofe be- neficial effeéts which refult when filver is purpofely added. Froma general view of the prefent experiments, there does not appear to be any very great or remarkable difference in the comparative wear of the three kinds of ftandard gold, all of which fuffer abrafion flowly, and with much difficulty ; and (as it has been already obferved) the difference of wear between the two laft mentioned, is certainly but inconfiderable. For thefe reafons, and from the confideration of every other circum- ftance, it muft be evident, that the extraordinary lofs which the gold coin of this kingdom is ftated to have fuftained within a certain limited time, cannot, with even a fhadow of proba- bility, be attributed to any important defeét in the compofition or quality of the ftandard gold ; and all that can be faid upon this fubjeét is, that fome portion of this lofs may have‘been caufed by the rough impreffion and milled edge now in ufe, by which each piece of coin aéts, and is acted upon by the others, inthe manner of a file. The lofs thus occafioned cannot however be confiderable ; for the quality of the prefent ftandard gold is certainly that which is well adapted to refift abrafion, efpecially in the cafe of the frition of coin againft coin ; and this is ftrongly corroborated by the obfervations of bankers and others, who are in the babit of fending or receiving large-quantities of gold coin from any confiderable diftance. When a number of guineas, rather loofely packed, have been long fhaken together by the motion of acoach or other carriage, the effects of friétion are obferved chiefly to fall upon only a few of the pieces, But it is not a little remarkable, that although thefe are often reduced nearly or quite to the ftate of plain pieces of metal or blanks, yet, upon being weighed, they are found to have fuftained little or no Jofs; and from this it appears, that the imprefliions have been obliterated, not by an aétual abrafion of the metal, but by the depreffion of the prominent parts, which have been forced into the mafs, and become reduced to a level with the ground of the coin. Pieces of hard gold would not fo eafily fuffer by depref- 4 fion; EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. 157 fion; but the real lofs would probably be greater, they being, in the cafe of the friétion of coin againft coin of fimilar quality, more fufceptible of abrafion. Upon the whole, there is every reafon to believe, that our gold coin fuffers but little by friction againft itfelf ; and the chief caufe of natural and fair wear probably arifes from extra- neous and gritty particles, to the a@tion of which the pieces may occafionally be expofed in the courfe of circulation. But ftill it muft be repeated, that the united effeéts of every fpecies of friétion to which they may be fubjeéted, fairly and unavoidably, during circulation, cannot produce any other. wear than that which is extremely gradual and flow, and fuch as will by no means account for the great and rapid diminution which has been obferved in the gold coin of this country. : SLC PION LL. ON THE SPECIFIC GRAVITY OF GOLD WHEN ALLOYED BY VARIOUS METALS. Difficulties in afcertaining the fpecific gravities of bodies, The problem of particularly from the inaccuracies of balances, the application aR i hig and temperature of water, and the porofity of the objeét itfelf, tended with nu- ~ Metals vary in their denfity by cafting in a mould, by fpeedy Bac diffi or flow cooling, and by hammering. ae Hammering and rolling is an imperfeét remedy, and not ap- Hammering. plicable to the brittle metals. The effeéts of alloys on the fpecific gravity of gold are very Alloys affeé& shine : > . the fpecific gra- intricate, and only capable of being determined by a direét zlteae cals caer trial; for a numerous feries of experiments clearly proved, not fingularly. only that the {pecific gravity of the compound may differ from the mean of the component parts, but that the effeét of the ~ fame alloy, inftead of being proportionate to the quantity em- = of pure filver, as it produced only an expanfion of 0,10. ployed, may differ confiderably from this. To the peculiar Compound effets produced by certain proportions of fome of the metals @lloys- mutt be added the effeéts peculiar to certain compound alloys, _ whence arifes an immenfe complicated feries of alterations in fpecific gravity, never yet inveftigated by philofophers. With regard to the expanfion or contra€tion of the compound, Expanfion pre- little alteration appears to be produced by alloying gold with a an gat by 3 " With copper it was 0,66: with equal parts of filver and cop- copper ; per 4 158 EXPERIMENTS ON VARIOUS ALLOYS OF GOLD. ’ t s y nervous only that which the x is to the mathematician ; and, if I be indifpofition. not altogether miftaken, the mathematician can with his x, bring more clear truths to light, than the philofopher by the word power, Ifa given power cannot be rendered fubfervient to deduétion, fo that, like Newton’s calculus, it fhall perfeétly accord with experience; nothing more will be determined or explained by the mere word power, than by the word {pirit; and I doubt much whether the new judicious Kantian fyftem of Dynamic natural philofophy, which confiders all bodies as mere aggregates of powers, would not rather cut the gor- dian knot than unravel it. It is not very uncommon that by a derangement of the corporeal powers, even without infanity and inflammatory fevers. apparitions do ftrike the eye externally, which are only internally the produétion of the imagination. The expe- rience of this may teach usa leffon of forbearance, not rafhly to confider as impoftors thofe well difpofed perfons who believe they have feen apparitions. But as manifold experience fhews us how far the human imagination can go in the external reprefentation of piétures; it may alfo admonith thofe well- difpofed perfons not to afcribe to their vifions any degree of reality, and ftill lefs to confider the effeéts of a difordered - fyftem, as proofs that they are haunted by {pirits. . The celebrated Juftus Mofer frequently believed that he faw flowers, Another of my acquaintance fees in like man- ner, at times, mathematical figures, circles, fquares, &c. in different colours. More examples of this kind may per- haps be found in Moretz’s Magazine, in Krueger’s Expe- rimental Pfychology, and in Bonnet’s Pfychological writings. The hearing of founds is a cafe which feldomer occurs. My much-lamented friend Mofes Meudeljohn had, in the year 1792, by too intenfe an application to ftudy, contracted a malady, which alfo abounded with particular pfychological apparitions. For upwards of two years he was incapacitated from doing any thing ; he could neither read nor think, and was rendered utterly incapable of fupporting any loud noife. If any one talked to him rather in a lively manner, or if he himfelf happened to be difpofed to lively converfation, he Gigad fell 174 Narrative and remarks on fpectres produ- ced by nervous indifpofition. SPECTRES OCCASIONED BY DISEASE. fell in the evening into a very alarming {pecies of catalepfis; in which he faw and heard every thing that paffed around him, without being able to move a limb. If he had heard any lively converfation during the day, a ftentorian voice re- peated to him while in the fit, the particular words or fylla- bles that had been pronounced with an impreffive accent, or loud emphatic tone, and in fuch a manner that his ears re- verberate. Seldom as it may happen, that perfons believe they fee human forms, yet examples of the cafe are not wanting. A refpeétable member of this academy, diftinguifhed by his merit in the fcience of botany, whofe truth and credibility are unexceptionable, once faw in this very room in which we are now aflembled, the phantafm of the late prefident Maupertuis. A perfon of a found and unprejudiced mind, though not a man of letters, whom I know well, and whofe word may be credited, related to me the following cafe. As he was recovering from a violent nervous fever, being ftill very weak, he lay one night in bed perfeétly confcious that he was awake, when the door feemed to open, and the figure of a woman entered, who advanced to his. bed-fide. He looked at it for fome moments, but as the fight was difagreeable, he turned himfelf and awakened his wife ; on turning again how- ever he found the figure was gone. But out of many cafes I have never known an inftance like my own, in which any per- fon had for almoft two months conftantly beheld fuch vifionary forms, and feemed even to have heard them; except it was that of two young ladies, who, as I have been credibly in- formed, frequently faw appearances of this nature. Iam by no means infenfible to a certain feeling which ad- monifhes me of the impropriety of talking fo much of myfelf in an affembly like this; but fince I tranfgrefs only with a fci- entific intention, to contribute to the knowledge of the effeéts of the human imagination, I muft endeavour to fupprefs this feeling. I may look for pardon, I truft, from thofe who know and refpeét every thing which tends to enlarge the ftock of human knowledge, even if I fpeak more of myfelf. For, when I proceed to defcribe the ftate of my imagination, and the nature of the apparitions during a previous malady, it will be merely with an intention to fhew the apparitions which form the fubje& of this le€ture in a lefs wonderful point of view, and SPECTRES OCCASIONED BY DISEASE. 175 and by that means perhaps to contribute in fome degree to the Narrative and illuftration of fo ftrange an incident. fein _I muft obferve that my imagination poffeffes in general a duced by nervous great facility in pi€turing. I have for example fketched in indifpofition, my mind a number of plans for novels and plays; though I have committed very few of them to paper, becaufe I was lefs folicitous to execute than to invent. I have generally arranged thefe outlines when, in. a chearful ftate of mind. I have taken a folitary walk, or when travelling I have fat in my Carriage, and could only find employment in myfelf and my imagination. Conftantly and even now do the different perfons whom I imagine in the formation of fuch a plot, pre- fent themfelves to me in the moft lively and diftin& manner ; their figure, their features, their manner, their drefs, and their complexion, are all vifible to my fancy. As long as I meditate on a fixed plan, and afterwards carry it into effet, — even when I am often interrupted, and muft begin it again at different times, all the aéting perfons continue prefent in the very fame form in which my imagination at firft produced them. I find myfelf frequently in a ftate betwixt. fleep- ing and waking, in which a number of piétures of every defcription, often the ftrangeft forms, thew themfelves, change and vanifh. In the year 1778, I was afflicted with a bilious fever, which, at times, though feldom, became fo high as to produce delirium, Every day towards evening, the fever came on, and if I happened to fhut my eyes at that time, I could perceive that the cold fit of the fever was beginning even before. the fenfation of cold was obfervable. This I knew by the diftin@ appearance of coloured pictures of lefs than half their natural fize, which looked as if in frames. ‘They were a fet of land{capes compofed of trees, rocks, and other objeéts. If I kept my eyes fhut, every minute fome al- teration took place in the reprefentation. Some figures va- nifhed, and others appeared. But if I.opened my eyes all was gone ; if I fhut them again J had quite a.different land- “Aecape. This cafe was therefore entirely different from what _ afterwards in the year 1791, when the figure remained un- changed during the opening and fhutting of the eyes. In {the cold fit of the fever I fometimes opened and fhut my eyes every fecond for the purpofe of obfervation, and every time a different pi€ture appeared. replete with various ob- jes 176 SPECTRES OCCASIONED BY DISEASE. Narrative and jeéts which had not the leaft refemblance with thofe that ap- remarks on {pectres pro- peared before. Thefe piétures prefented themfelves without duced bynervous interruption, as long as the cold fit of the fever lafted. They indifpofition. became fainter as foon as I began to grow warm, and when I was perfectly fo, all were gone. When the cold fit of the fever was entirely paft, no more piétures appeared; but if on the next day I could again fee pi€tures when my eyes were fhut, it was a certain fign that the cold fit was coming on. I muft further obferve, that when I either think deeply on a fubjeé, or write attentively, particularly when I have exert- ed myfelf for fome time, a thought frequently offers itfelf which has no connection with the work before me, and this at times in a manner fo very lively, that it feems as if ex- preffed in aétual words. Thisnatural vivacity of imagination renders it lefs wonder- ful, that after a violent commotion of mind, a number of delufive pi€tures fhould appear for feveral weeks in fucceffion. Their leaving me on the application of leeches, fhews clearly that fome anomaly in the circulation of the blood was con- nected with the appearance of thofe phantafms; though it may perhaps be too hafty a conclufion to feek for their caufe in that alone. It feems likewife remarkable, that the be- ginning of the apparitions, after. the difturbance in my mind was fettled, as well.as the alteration which took place when | they finally left me, happened exaétly at the time when digeftion commenced. It is no lefs remarkable, that the ap- paritions before they entirely ceafed, loft their intenfity of colours; and that they did not vanifh or change as formerly, but feemed gradually to diffolve into air. Had I not been able to diftinguith phantafms from pheno- mena, I muft have been infane. -Had I been fanatic or fu- perftitious, I fhould have been terrified at my own phantafms, and probably might have been feized with fome alarming diforder. Had I been attached to the marvellous, I fhould have fought to magnify my own importance, by afferting that I had feen fpirits ; and who could have difputed the faéts with me? The year 1791 would perhaps have been the time to have given importance to thefe apparitions, In this cafe however, the advantage of found philofophy, and deisberate obfervation may be feen. Both prevented me from becoming either a lunatic or an enthnfiaft; with nerves fo ftrongly ex- | cited SPECTRES OCCASIONED BY DISEASE; 177 cited; and blood fo quick in circulation, either misfortune Narrative and might have eafily befallen me. But I confidered the phan- remarks on tafms that hovered around. me as what they really were phe A 2 duced by nervous namely, the effects of difeafe; and made them fubfervient to indifpofition. my obfervations, becaufe I confider obfervation and refle@ion as the bafis of all rational philofophy. Our modern German philofophers, will not allow that obfervation ought to be admitted in theoretical philofophy. Hence arofe Kants’ Tranfcendental Idealifm, which at laft degenerated into the grofs enthufiaftic idealifm; which is found in Fichte’s writings. This philofopher confiders all external objects as our own produdtions. “ What we con- “* fider as things independent of us are,” according to him, “no more than our own creatures, which we fear, admire “‘ and defire ; we believe our fate to be dependerit on a * fhadow, which the fingle breath of a free being might * deftroy.”” Thefe are Mr. Fichte’s own words *. The mere pigture in the mind, without external experience, would never be fnfficient to afford us a convincing proof; whether we faw phenomena or phantafms. The critical philofophers maintain, that knowledge deduced from obferva- tion is merely empirick, and therefore not to be depended on; it is perhaps true that nature has affigned us no greater certainty than this refpeéting our ideas. But could we be truly confcious of our grounds of reafon, if the appearances called external, which follow laws that do not depend on the re- prefentations in our mind, did not continually agree with thofe reprefentations ? Are we poffeffed of any other criterion? Does not the great theoretical philofopher, when he fees _ every thing yellow, conclude that his eye is jaundieed ; or _ when every thing appears black to him, that his brain is _ affeGted? In thefe cafes he does not truft his imagination or _ mental powers alone. I may here apply the confideration of the illufions which I witneffed. I am well aware that no general conclufions can be drawn from a fingle inftance ; but ftill the experience _ Of a fingle cafe, if accurately obferved and faithfully defcribed, is fufficient to deftroy hypothefes which have too long been _ honoured with the name of fyftems. Ae tei tee er * Fichte’s Appeal; p. 44. Vor. VI.—Novemser, 1803. N _ According aes 178 SPECTRES OCCASIONED BY DISEASE, Narrative and According to Fichte, fince during the fituation I have above remarks on : 4 Sip fpe€tres pro- deferibed, I was in other refpeéts in the perfeét ufe of my duced by nérvous reafon, as well as the perfons who were really about me; as indifpofition. ce : . the apparitions which I faw, as well as thofe which are con- fidered as realities, were the one as well as the other, my own produétions:—Why then were my creatures of both kinds fo effentially different ? My judgment fhewed me this plainly, by conclutions founded on the previous courfe of obfervations. The greateft modern idealifts who depend fo much on the confufion in which they have involved themfelves by the fuppofed depth of their fpeculations, will certainly never pretend that both perceptions were of the fame nature; fince if fo, T could not have inveftigated their difference? But by what means could this be done? I obferved that real perfons followed in a determinate order, by external laws that do not depend on me, inan order that I myfelf muft continually follow, as was evident from my fenfe of confcioufnefs. I could alfo lay hold _ of the real objets, as well as of myfelf. Neither of thefe circumftances was, however, the cafe with the phantafms ; I had always found it fo in the conftant obfervation of my elf, of the apparitions without me, and in my own confcioufnefs. The phantafms, as well as the phenomena, no doubt, lay in my mind; but I am neceffarily compelled to afcribe to the latter, the fame reality which I am obliged to afcribe'to myfelf; viz. fomething that does not lie in my mind alone; fomething that alfo exitts without my mind; fomething independent of my con{cioufnels, which determines the nature of my idea 5 fomething which we formerly ufed to call the thing itjélf, ‘be- fore the critical philofophy fo unjuftly reprobated this unex- ceptionable term. On the contrary, however, I could ‘not a{fcribe this fame reality to the illufion ; I could form no other eonclufion, than that they originated in my internal confciouf- ; nefs alone; in a confcioufnefs which was alfo difordered, ~ as I might juftly conclude from the obfervations I made on — myfelf. I repeat, that both the phenomena and the phan- ~ tafms exifted in my mind: if I had not been able to diftinguifh — between them, I muft have been infane. By what means | could I diftinguifh, if I did not attribute reality to the | former ;—and that they poffeffed reality, Iinferred from ob- fervations frequently collected on the fhores of the Ifland of Maragnan, ANALYSIS OF AMBERGRIS; : 179 fervations to which I am fill inclined to give confidence, until Mr. Fichte can more clearly convince me that it ought - in no cafe to be depended on. [ES SO I SR TES I > | Il. Analyfis of Ambergris ; by Cit. Bourtton La Grance*, \ Iv: is an opinion now generally adopted, that ambergris is Ambergite fod formed in the ftomach of the cachalot, or fpermaceti whale, \ ie hye phyfeter macrocephalus, and appears to be a produét of its iiderece plates digeftive faculties. tr, Swediaur has fhewn, in his inquiries into the. nature Beaks of cuttle- and origin of ambergris, that the beaks of the cuttlefifh, in- a a iy all terfperfed throughout all the large pieces of ambergris, that me Efe are found fwimming on the fea, or caft upon the. fhore, as well as thofe extraéted from the bellies of whales, belong to the fpecies called by Linneus fepia oftopodia. The exiftence of thefe beaks and other foreign f{ubftances in ambergris evidently proves it to have been originally in a foft or fluid whence it muf fiate. Dr. Swediaur afferts, that the whale, in the belly Beg cad nae which ambergris is found, is the fame fpecies as that from The fpermaceti whale that which ect 3 is extracted, which appears to be the phy/éter é produces its macrocephalus of Linneus ; and feeds chiefly on the large fpecies © of cuttlefith., The ambergris is found in the inteftinal canal of this fifh; it is a fource of difeafe to it +; and after it iffues Occafionsa from the cavity in which it had been included, it gradually oat te the acquires the folidity it is known to poffels. lid eee Ambergris is found in the Indian Seas, near the Moluccas, exclufion. Found on the ~ Maldivia Ifiands, and Madagafcar, on the coafts of China ,,.¢5 ofthe and Japan, and from Jolo to the Philippine Iflands. It is Indian Ocean and its iftandss or of Brazil; but more commonly on thofe of Africa, toward Of Brazil, cape Blanco, the gulf of Arguin, the bay of Portendie, and nd alfo of Africas on fome other Iands, that extend from Mofambique to the aay # Red Sea. % Annales de Chimie, No. 139. or XLVII. 68. 4 Is it not rather the effe&, than the caufe of difeafe? J.C. N 2 From 180 The inhabitants ef the Samballas feek for iton the fhore after ftorms by the {mell. Certain birds and other animals fond of t. Certainly a vegetable pro- dudtion. Excrements of fome animals, particularly of the ox and pig, refemble it in fmell. Cowdung called in fome places Native mufk. External quali- ties of amber gris. Its odour more powerful as it grows old, or when mixed with other per- fumes. Marks of good ambergris. The older che- mitts claffed it among the bitu- mens, Geoffroy’s analyfis of it b alcohol, and by diftilla- tion, ANALYSIS OF AMBERGRIS. From the accounts of various travellers, the inhabitants of the Samballas feek for it in a fingular manner: they hunt it by fcent. After a ftorm they run along the fhore, and if any ambergris be thrown up, they findit by the {mell. There are certain birds and other animals on thofe coafts, that are very fond of ambergris, and, attraéted from a diftance by its {mell, they fearch for it to eat. There is no doubt, that ambergris is a vegetable produétion. Many fubftances refemble it greatly in fmell, fuch as the ex- crements of mammiferous animals, particularly thofe of the ox and the pig. I have found, that cowdung dried in the fun, has a fmell much like that of ambergris, and even of mufk, whence in fome countries this fubftance, fo prepared, has re- ceived the name of native mufk. Ambergris, ambra grifea, isa light fubftance, fwimming on water, folid, opaque, of an afhen gray colour ftreaked with white and yellowith brown, flightly odoriferous, its odour dif- playing itfelf more as it grows old, or when it is mixed with mufk or other aromata, as is done in preparing perfumes or odoriferous waters, ; In its natural ftate good ambergris is known by adhering like wax to the edge of a knife with which it is fcraped, retaining the impreffion of the teeth or nails, and emitting a fat odori- ferous liquid on being penetrated with a hot needle. Though folid, and in general brittle, it is not hard enough to take a polith; but on rubbing it with the nail it becomes as fmooth as hard foap. Geoffroy, Neumann, Grim, and Brow, have claffed am- bergris among the bitumens. ‘The analyfis made of it by thefe chemifts was inadequate to determine its nature. Ambergris, fays Geoffroy, melts into a refin of a yellow or gold colour ; kindles, and burns with flame, Spirit of wine does not diffolve itentirely; a black fubftance like pitch being left, on which it does not aét. When it is diffolved, it lets fall after fome time a white cloudy fediment, which gradually coagulates, and grows thicker and thicker. This coagulum, on drying, changes to a fhining foliated earth, nowife different from {permaceti. On diftillation, according to the fame chemift, ambergris yields at firft an infipid phlegm, then an acid fpirit or liquor and ANALYSIS OF AMBERGRIS.. 18] and a very odoriferous yellow oil, with a fmall portion of a volatile acidofaline falt ; and laftly, a fhining black bituminous fubftance remains at the bottom of the retort. Hence we Thisanalyfis ine fee this analyfis, which does not differ from thofe related by isiest- all other chemifts, requires to be revifed, in order to give us determinate ideas of the nature of this fingular fubftance. It is perhaps neceflary to apprife thofe, who wifh to repeat Neceffary to be thefe experiments, that they fhould pay great attention to the itis >) choice of the ambergris. Many varieties are found in the Many varieties fhops, the different kinds of which are diftinguifhed by their of itm the thops price. No doubt this fubftance is fabricated, as caftor is in fome parts of Germany. Bayen affured me, that he had Fabricated by feen it made at Frankfort; and it is well known that this 2% 28 Bayes : : faw at Frankfort father of chemiftry faw clearly, and that his memory was not apt to deceive him; and, what is very rare among travellers, that he never told a lie. I have examined feveral fpecimens of the ambergris of the Differences of fhops: fome varied in fpecific gravity, were more or lefs deep thefe varieties, in colour, had very httle fmell, and were flexible ; others were of an afhen gray colour, and tolerably hard; and fome were almoft ftony, fcarcely at all foluble in alcohol, and void of fmell. | The ambergris I analyfed was not purchafed from the fhops; and, on comparing it with that in the cabinet of the Mufeum, I could find no difference, either in colour or in {mell. Phyfical Properties. It is of an afhen gray colour, internally variegated with a Its colour, fmell, few yellow ftreaks, of a fweet and pleafing fmell, foftening texture, between the fingers; when reduced to a fine powder it is of a deeper colour; pounded in a glafs mortar it agglutinates, and adheres to the peftle. -Of a flat and almoft infipid tafte, exhibiting the fame ap- tafte, pearances as wax when chewed between the teeth. Its fpecific gravity is to that of water as 844 or 849 to fpecific gravity. 1000. According to Briffon, the fpecific gravity of ambergris is 9263; the weight of the French cubic inch, 4gros 58 grs.; that of the cubic foot, 64 Ibs. 140z. 3 gr. 47 grs. * * The fpecimens of ambergris, on which Briffon made his ex- periments, were taken from the king’s collection, The \ 182 ANALYSIS OF AMBERGRIS. The fpecific gravity of the blackifh gray ambergris 7803 ; the weight of the cubic inch, 4 gros 3 grs.; that of the cubic foot, 541bs. 9 oz. 7 gr. 35 grs. Chemical Properties. Ttburns entirely Experiment I. Ambergris burns, and is entirely diffipated, Hh al when placed on a red hot coal. It leaves behind an agreeable fmell. Melts with alefs If the combuftion be conduéted more flowly, in a crucible dss ated platina, the ambergris melts, diffufing the fame f{mell. The fmell of a fatty fubftance may be diftinguifhed like- wife, Nothing remains in the crucible, but a-greafy black fpot., and is then a 50° of Reaumur’s thermometer are fufficient to melt it, and fhining brown s ee : @uid. _ a fhinmg brown-fluid is thus obtained, Becomes volatile At 80° it is volatilized im the form of a white vapour. ih ths ‘aj. Exp. Il. The fmell perceived ‘during its volatilization catesan acid. having led me to fufpeét the prefence of an acid analogous to that of balfams, an experiment was made to afcertain this. a oe eae A bit of ambergris was placed in a china capfule, covered porating it under With a bell, in which was fufpended fome litmus paper. a bell, This apparatus being placed on a fand-heat, the temperature was railed fufficiently to volatilize the ambergris, and the paper was very quickly reddened. Nothing now remained but to determine the nature of the acid; and for this purpofe _ and proved to be Schelee’s procefs for extra@ting the acid of Benjamin was the benzoic, adopted. The produét was examined, and left no doubt of their analogy. On diftillation, Exp, III. The analyiis by diflillation in a retort added nothing to the knowledge we already poffefled of the nature of ambergris. it gives out a A gentle heat melted it: on raifing the fire it was decom- Ee teihia pofed, and there pafied over into the receiver a whitifh acid light oil, and liquor with a white oil, partly foluble in alcohol, which gave ash abulky it a yellow colour, In the retort remained a light and very * bulky coal. Imparts neither fivp. LV. Ambergris {wims on water, and is not penes tafte nor {mell : . : é 4 to cold water, a by it when cold.” It imparts to it neither taite nor Mei, Boiling | f 2 J i SP PA a AS at a it foluble foaps. ANALYSIS OF AMBERGRIS. 183, Boiling water is equally incapable of altering its properties. and to boiling In this degree of heat the ambergris melts, aaa appears in the ieee form of a isiokevifi oily fluid ; re a {mall quantity of black bitter tafte. matter, infoluble in alcohol, feparates from it. The filtered liquor has neither colour nor fmell, it has however a flightly bitterith tafte. It is only in confequence of the temperature therefore that the ambergris melts, fince on this being lowered it re- fumes the fame properties as before. Exp. V. Acids in general have little ation upon amber- gris. Thefe agents likewife do not enable us to difcover the conftituent parts of this compound fubftance. Dilute fulphuric acid effeQs no change in it, The con- S¥!phuric. centrated acid expofes a little oxide of carbon. The fame phenomena are produced by the muriatic an oxigenated muriatic acid. The nitric acid, at 18°, diftilled over this fubftance in the hee pneumato-chemical apparatus, produces nitrous gas, carbonic bonicacid, and acid, and azote gas, A ae The azote gas arifes no doubt from the decompofition of fome animal matters, accidentally mixed with the ambergris, as may be obferved in the examination of {ome pieces. After the extraGtion of the elaftic fluids, a thick liquor, in- and leaves a fub- ftance analogous Acids act but feebly on it. d Muriatic. _ clining to a yellow colour, was found in the retort: this, OM to refins, bringing it to a foft confiftency, flightly {welled up; and being evaporated to drynefs, in a porcelain capfule, what ‘remained was a dry, bitier fubftance, of a golden yellow hue, fining and tranfparent, and exhibiting properties analogous to thofe of refins. - Exp. V1. Alcalis combine with ainbergris, and form with Alcalis form foap with ambere ; : : gris. ’ Into-a crucible of platina were put one gramme, 592 (30 _ fr. grs.)of ambergris, with 531 thoufandth of a gramme (10grs.) _ of pure potath ; it was gently heated; the mixture melted, 4 without exhibiting any figus of the prefence of ammonia ; on cooling a homogeneal brownifh mafs was obtained. On this were poured 30 grammes (one fr, ounce) of diftilled : water, which diffolved part of it, The folution was very _alcaline. The undiffolved portion remained in a foft tenacious mafs, by which adhered to the fingers when warm. 2 : A large a 184 ANALYSIS OF AMBERGRIS. A larger quantity of water was added, and the whole was diffolved. Cauftic potahh Cauftic potafh triturated for fome time in a mortar with does not facili- ‘ hive P Sere tate its {olution 2™Mbergris does not facilitate its folution in water. in cold water. Ammoniac does not aét on ambergris cold, but when heated - aaatig diffolves it; the mixture gradually becomes brown, and on the aidof heat. evaporation yields a glutinous faponaceous fubflance, in all re- fpects fimilar to that obtained by means of potafh. Itis folublein Exp. VII.° The fixed oils, as thofe of rape, olive, &e. the fixed oils, diffolve amber with the affiftance of heat in a very fhort time ; the folution is yellow and tranfparent, and becomes brown on being evaporated. galas the volas Exp. VIII. ' Volatile oils likewife diffolve ambergris. ; ‘ Thofe of turpentine, favine, and hyffop, exhibit the fame appearances. The folution affifted by heat takes place pretty readily. On evaporating On evaporation a thick red magma is produced, incapable folution a 6f complete deficcation, burning on the coals, and emitting a magma is 5 left, whichis denfe fmoak, of a fmell refembling that of the ambergris. Sati in al- Alcohol diffolved this fubftance, and thence acquired a golden ; yellow colour, but it was precipitated from it by means of water. Old volatile oils If volatile oils be too old, they will not completely diffolve Aa no. diffolve i+ even with the help of long continued heat. Soluble inether, Exp. 1X. It diffolves very quickly in ether, even cold. ace ea Exp. X. The folution of ambergris by alcohol is the only flituen: parts, “one that is really capable of affording us any certain refults. Its conftituent parts may be feparated by it in fuch a manner, that on reuniting them a compound is obtained, the qualities of which came very near thofe of the original fubftance. Part diffolved in 3.821 grammes (one drachm) of ambergris were reduced to he without powder, put into a phial, and 61.143 grammes, (two ounces) 2 twenty four hours was fufficient to give the alcohol a deep yellow colour ; it was filtered, and a frefh quantity of alcohol another part by was poured’on the undiffolved portion. The folution was means of heat; facilitated by increafing the temperature. The whole of the Jeaving a little 3 : es : black matter; ambergris being diffolved, except a fmall quantity of black and feparating matter, the liquor was filtered while hot. It paffed through when cold, the filter clear; but on cooling there feparated from it a light pale yellow fubflance, part of which adhered to the fides of the veffel, The : of reétified alcohol were poured on them. A maceration of, \ ANALYSIS OF AMBERGRIS. 185 The firft folution in alcohol made without heat} and that This folution which was poured off from the precipitate, were mixed to- aay or gether, and evaporated to the confiltence of an extraét: it was then of a reddith yellow colour, adhered to the fingers, had an agreeable {mell, and a pleafant tafte. The evapora- le/t a refinous : d : : ake ubftance. tion being continued to drynefs, it appeared fhining and tranf- parent, grew foft between the fingers, and burnt in the fame manner as refins. The experiment was repeated, to determine the characters of thefe two fubflances more pofitively. For this purpofe ambergris was left to macerate in alcohol phe experiment twenty-four hours as before ; it was then filtered, and a frefh repeated. quantity of alcohol was added to the refiduum, which was macerated in the fame manner. The fecond liquor was lefs coloured than the firft, A third portion of alcohol being poured on what was left undiffolved ; its colour was fcarcely altered. The flight a€tion of the alcohol on this refiduum feemed to indicate, that it was no farther foluble in this menftrum ; but I quickly found the contrary. I heated the mixture, and the whole was inftantly diffolved, leavmg about 212 thoufandths of a gramme, (four grains) only of a black powder, which The plack was nothing but oxide of carbone. The {olution was filtered powder oxide hot, and on cooling a whitifh yellow glutinous fubftance was of Sanaa depofited, which was feparated from the tin¢ture. This experiment fhows us the poffibility of feparating és Thue these means of alcohol three very diftin@ fubftances ; the firft foluble ¢'ferent tub- jagices fepa- init cold; the fecond, by means of heat; and the third in- pateg, foluble, which remains in the form of powder. To determine the charaéters of the firft two fubftances, the whe Gch eve tin@lure made without heat was firft evaporated to drynefs; amined. when there remained in the capfule 1.167 grammes (22 grains) of a brown fubftance, dry and fhining in its fraéture, unaltera- ble in the air, and growing foft witha gentle heat ; 15° were fufficient io give it a tenacious and glutinous confiltence ; and being put on red-hot coals it was completely volatilized.. If this experiment be made in a filver {poon, the volatilization takes place with the fame rapidity, an odoriferous {mell is diffufed around, and no coally refiduam is left. Sufpeéting this fubftance might be in fome refpeé analogous pers from the to the refin obtained from propolis by Cit. Vauquelin, I in- refio obtained ftituted a comparifon between them, and found the following from propolis _ differences ; ift, 186 ANALYSIS OF AMBERGRiS, in three ree Ift. It melts much ‘more flowly ; Qdly, it diffufes a denfe a nai odoriferous vapour, refembling a little the fmell of honey 5 — 3dly, it {wells up, and leaves a very bulky coal. Finally, this firft fubfance obtained from ambergris, which may be confidered as a true refin, -is foluble in alcohol, and is precipitated by water. The folution reddens litmus papery 7 which proves too, that the alcohol. diffulves the benzoic acid previoufly dete@ted, either hy burning the ambergris under’a bell, or by treating it with lime. Examination of _ Nothing now remains, but to examine (he produét obtained the fecond fub- 5 ; ; ; : Rance. © Dy heated alcohol, after the refin is extraéted by maceration. I have faid above, that there feparated from the alcohol by refrigeration a fubftance, part of which fubfided to the bottom of the veffel, and part adhered to the fides. Being feparated from the liquor, and properly dried, it remains a littie bulky and light. Under the preffure of the finger it contraéts and crumbles, but it 1s foon lengthened out and foftened by the heat. It has a laminated texture, if it be- fuffered to cool flowly, Js a true refin, It retains between its particles a little water.and alcohol, which may be feparated by keeping it a fhort time in fufion, When melted over again it is much whiter than before, and Its properties no longer exhibits its former granulated texture. In fine, the fame with bh { pd | - - EM . . | : , b Bhoke of the ave difcerned in it all the properties of the adipocerons fub- adipocerous fub-fiance, difcovered by Cit. Fourcroy in the fatty matter of detec dead bodies, and the properties of which he has deferibed in a of dead bodies. paper publifhed in the 8th volume of the Annals of Chemifiry. From 3.821 grammes, (72 grains) of ambergris, 2.016 grammes, (38 grains) of adipocerous maiter may be obtained. / Recapitulation. From thefe experiments it appears we may conclude: Recapitulation, 1 ft, That ambergris isa compound fubftance, which burns, and may be entirely volatilized. 2dly, that on diftilling it alone we obtain from it a flightly acid liquor, and an oil partly folubie in alcohol, and of an empyreumatic {mell, — 3dly. That by fublimation, or by the procefs of Scheele, — benzoic acid may be extraéted from it. 4thly, That water does not aét upon it. 5thly, bi | - - STONES FALLEN ON THE EARTH. 187 '. Sthly. That by means of nitric acid a mattér analogous to refins, mixed with the adip6cerous fubftance, is extrac¢ted from it. 6thly. That the concentrated fulphuric, muriatic, and oxigenated muriatic acid, convert it to a coal, without dif- folving it. 7thly. That with alcalis it forms a faponaceous compound. 8thly. That fixed oils, volatile oils, ether and alcohol, are the true folvents of ambergris. : 9thly. And lafily, that alechol affords the means of feparat- ing its conftituent parts in the following proportions, _ Adipocerous matter | - - - - 2.016 grammes. Its conftituent ® Refin - 4 “ ~ = £ - 1.167 Eattss _ Benzoic acid - ms - - - 0.425 i Coally matter Bit leap ket a) te UBUD q i 3.820. ; ; ; LV. An, Account of fome Stones faid to have fallen on the Earth in France ; and of a Lump of native Iron, faid to have fallen in India. By the Right Hon, Cuarres Grevite, F. R. §*, a | | Tue experiments and obfervations made by Edward How- That ftony and ard, Efg. on certain ftony and metalline fubftances faid to M*tallic bodies a, have fallen on have fallen on the earth, and the accurate defcription which the earth is the Count de Bournon has given of thofe fubftances, have, fly *fablithed. _ in my opinion, fully eftablifhed the following faét, namely, . - that a number of ftones afferted to have fallen under fimilar _ circumftances, have precifely the fame characters. The ftones from Benares, that from Yorkfhire, that from _ then been feenin England, They ail contained pyrites of a pe- _ culiarcharaéter’: they all hadacoating ofblack oxide of iron: they _ all contained an alloy of iron and nickel ; and the earths which _ ferved to them as a fort of conne@ting medium, correfponded _ in their nature, and nearly in their proportions. i Since the publication of Mr. Howard’s and Count de Three new fpe~ ~Bournon’ s obfervations, I have received from France three oe from ranc€e~ * From the Philof. Tranf. 1803, additional i 188 Remarkable additional fpecimens. Monfieur St. Amand very obligingly biftory. divided with me'a fpecimen he had broken from a ftone of about 15 inches diameter, preferved in the Mufeum of Bourdeaux, which ftone fell near Roqueford, in the Landes, on the 20th Auguft, 1789, during the explofion of a meteor; it broke through the roof of a cottage, and killed a herdfman and fome cattle. M. St. Amand alfo gave me part of a ftone he had preferved in his colleétion ever fince the year 1790, whena fhower of ftones, weighing from 4 an ounce to 15 and 25 pounds each, fell in the parifhes of Grange and Creon, and alfo in the parifh of Juliac, in Armagnac; which faét was, at the time, verified by Duby, Mayor of Armile, and publithed by Bertholon, in the Journal des Sciences utiles de Montpellier, in the year 1790. a The third fpecimen, I owe tothe Marquis de Dree ; it is a fragment, broken from a ftone of 22 pounds weight, which fell near the village of Salles, not far from Villefranche in Burgundy, on the 12th of March, 1798; this was alfo ac- companied by a meteor. Thefe three I content myfelf with the mere recital of the faéts, mm con« = aan firmation of the obfervations prefented to the Society, as thefe the others, three additional fpecimens have precifely the fame characters, texture, and appearance, as the others in my colleétion; and are {carcely, by the eye, to be diftinguifhed from them. I fhould not, perhaps, have troubled the Society with this account, as my friend the Marquis de Dree, whofe knowledge in mineralogy peculiarly qualifies him to inveftigate thefe fub- jects, has given me hopes of feeing his obfervations on them publifhed ; but a new evidence has lately fallen into my hands, and is the only one I have met with that afcertains the origin of native iron, which from analyfis, had been fufpected to have Metallic ftone @ Conamon origin with the {tones fallen on the earth. Con- that tell in India yerfing with Colonel Kirkpatrick, whofe refearches have rir a, “™" embraced both the literature and politics of India, and whofe talents had placed him in very important filuations in various parts of India, I inquired whether he had ever heard of any inftances fimilar to the explofion of the meteor at Benares in 1798. He told me, he could not recolleét having heard or’ read of any other inftance, excepting one in the Memoirs written by the Emperor Jehangire, and of that he did not recolleét the particulars. A few days after, having found the paflage STONES FALLEN ON THE EARTH. / STONES FALLEN ON THE EARTH. 189 paffage i in the origival Perfian, he was fo obliging as to tranflate - it. Iconfider it as an authentic fa@; for the Emperor Jehan- gire was nota prince on whom his courtiers would idly venture to impofe; and there can be-little probability that an Aumil of a diftrict fhould invent fuch a ftory, or be able to produce a fubftance apparently like iron, but which, on trial, differed from manufaétured iron. Colonel Kirkpatrick’s tranflation I have obtained his leave to communicate, with his atteftation, to the Royal Society. Extra& from the Memoirs of the Emperor Jehangire, writien (in Perfian) by himfelf, and tranflated by Colonel Kirkpatrick. A. H. 1030, or 16th year of the reign.—The following is Narrative among the extraordinary occurrences of this period. eas oe Early on the 30th of Furverdeen, of the prefent year *, and gire of a metallic in the Eaftern quarter, fof the heavens] there.arofe in one of ripeness a the villages of the Purgunnah of Jalindher +, fuch a great and : i tremendous noife as had nearly, by its dreadful nature, dauvinel the inhabitants of the place of their fenfes. During this noife, a luminous body [was obferved} to fall from above on the earth, fuggefting to the beholders the idea that the firmament “was raining fire. Ina fhort time, the noife having fubfided, and the inhabitants having recovered from their alarm, a courier was difpatched [by them] to Mahommed Syeed, the Aumil ¢ of the aforefaid Purgunnah, to advertife him of this event. The Aumil, inftantly mounting, [his horfe,] proceed. ed to the fpot, [where the luminous body had fallen]. Here he perceived the earth, to the extent of ten or twelve guz §, in length and breadth, to be burnt to fuch a degree, that not _ the leat trace of verdure, or a blade of grafs remained ; nor had the heat [which had been communicated to it] yet fub- fided entirely. _ ™® The firft of Furverdeen of this year, (A. H. 1030,) cor- _ refponded with Saturday, the 27th of Rubbi ul Akhir; con- fequently, the 30th of Furverdeen fell on the 26th of Jummad ul _ Ouwul, or A. D. 1620. _ A purgunnah is a territorial divifion, of arbitrary extent. _ The purgunnah of ‘falindber is fituated in the Punjaub, and about 100 miles S. E. of Lahore. + Aumil is a manager or fiscal fuperintendant of a diftri&. A, guz is rather lefs than a yard. S48 i Mahommed 190 STONES FALLEN ON THE EARTH. Mahommed Syeed hereupon directed the aforefaid {pace of ground to be dug up; when, the deeper it was dug the greater was the heat of it found tobe. At length, a lump of iron made its appearance, the heat of which was fo violent, that one might have fuppofed it to have been taken from a furnace. After fome time it became cold; when the Aumil conveyed it to his own habitation, from whence he atfter- wards difpatched it, in a fealed bag, to court. It weighed up- Here I had [this fubftance] weighed in my prefence. Its ied hah weight was one hundred and fixty tolahs.* I committed it: brittle. to a ikilful artifan, with orders to make of it a fabre, a knife, andadagger. The workman [foon] reported, that the fub- ftance was not malleable, but fhivered into pieces under the hammer.t Upon this, I ordered it to be mixed with other iron. Con- formably to my orders, three parts of the iron of lightmings. were mixed with one part of common iron; and from the mixture were made two fabres, one knife, and one dagger. With the addi- By the addition of the common iron, the [new] fubftance ai ei acquired a [fine] temper; the blade [fabricated from it} of common iron to three parts of proving as elaftic as the moft genuine blades of Ulmanny,§ Ake ah and of the South, and bending, like them, without leaving 5) 3 js > ; blades were any mark of the bend. I had them tried-in my prefence, a ee and found them cut excellently; as well [indeed] as the belt genuine fabres. One of thefe fabres I named Kataz, or the cutter; and the other Burk-ferifht, or the lightning-na- tured. A poet|| compofed and prefented to me, on this occafion, the following tetraftich. ~ « This earth has attained order and regularity through the. ‘« [Emperor Jehangire : ‘<< Inhis time fell raw iron from lightning : «« That iron was, by his world-fubduing authority. «« Converted into a dagger, a knife, and two fabres.” * A tolah is about 180 grains, Troy weight. t + Literally, ‘¢ it did not ftand beneath the hammer, but fell to - i pieces. . i { This expreffion is equivalent to our term thunder-bolt. § The name of the place here defigned is doubtful. 7 || The poet is named in the original ;. but the name is not per> | fectly legible. om | AWALYSIS OF THE NATROLITE. 191 The chronogram. of this occurrence is contained in the ‘words* ( . - ) which fignify ‘ the flame of the imperial lightning ;” and give the year (of the Hegera) 1030. N. B. The foregoing tranflation (which is nearly literal} has been made from a manufcript that has been feveral years in my poffeflion; and which, although without date, bears marks of having been written at a remote period. WM. KIRKPATRICK. \ V. Analyfis of the Nairolite. By Kuarrotu.t x ‘ 4 Fa > q ‘| HE foffil which forms the fubjeé& of this analyfis, and to Natrolite found ” fpecific gravity. Bes ) fome time ina 4lver crucible, loft nine grains. The figure . into a tranfpare snt clafs, full of {mall air bubbles. heat of a porcelain furnace, fufed into a tranfparent glafs of a light brown colour. q2t mn in which I give the name of natrolite, for reafons to be ftate Se he hereafter, is found at Hégau in Suabia, on the borders of Switzerland, It is depofited in the crevices, or clefts and ca- vities of the fonorous porphyry. (Klinginftein Porphyr) from having a found, nearly metallic, which form the mountains and rocks of Hohentwie!, Hohenkrahen, and Magdeberg. The colour of this foffi! is a dirty ochreaceous yellow, ap-Itscoloura dirty proaching fometimes to an Ifabella yellow, at other times to Yellow. a yeliowifh brown, interfeéted with concentric white lines, It is compaét, its internal fracture hasa filky luftre. It breaks Its properties "into wedge-like pieces, the edges of which poffefs little tran- parency ; if is not very hard, extremely brittle, and of=2,200 A a. 100 grains of natrolite, after having been ignited for Ignited ina ss filver crucible, of the ftone was retained, but its compaétnefs was con- ) fiderably diminifbed. b. the blow-pipe on charcoal, natrolite fufes quickly Fufes quickly Before the blow-pip q ¥ Before the blow- PIR : c. Natrolite placed in aclay crucible, and expofed to the Ina porcelain furnace melts into a brown glafs, \ _* The Perfian “charaéters are given in the Tranfactions. N. + Abftra& of an Effay in the memoirs of the Royal Academy of Sciences at Berlin, 1803, page 243. ; d. In 2 ANALYSIS OF THE NATROLITEs with minute d. In a charcoal crucible the mineral afforded the fame globules of iron in the furface, Produét. The glafs pearl exhibited on its furface.minute glo- bules of iron, ; B. 'Diffolved in a. 100 grains of finely levigated natrolite, were mixed into Batre abides 7 pafty fluid with water, put into a flafk, and digefted in mo- derately ftrong muriatic acid. The folution was foon effeéted, and it exhibited a reddifi yellow gelatinous mafs. After di- The filiceous —_Jyting it copioufly with water, and continuing the digeftion, earth being pre- : ‘ é d cipitated by the filiceous earth feparated, which, being colleéted an watery dried, weighed 48 grains. cubic cryftals b. The fluid altatnedl in the laft procefs on evaporation, were obtained. yielded cubic cryftals, The remaining fluid being further The dry mafs evaporated to drynefs, the dry mafs was pulverifed, and di- digefted in ale gefted with a gentle heat in alcohol. Having fuffered the al- i coholic folution to cool, a white faline powder was depofited ; the alcohol was therefore decanted, and the powder colle&ed, wafhed in fpirit, and dried. The remaining alcoholic folution was afrefh evaporated, a fmali quantity of the fame faline powder became feparated, which was added to that obtained before. The refiduum c. The refidue of the procefs b infoluble in alcohol, was age in Was" diffolved in water, On adding to this folution liquid ammonia, ~ precipitated by alight flocculent precipitate became depofited. This being miineiei feparated by the filtre, the fluid which paffed through, was evaporated by a gentle heat. The falt obtained, weighed when perfeétly dry, 313 grains. The folution in . The alcoholic folution 6 (which from other experiments, — alcohol decom- was known already to contain nothing but alumine and oxide | pofed by am- ; ; : : saghia of iron) after being diluted with water, was decompofed by liquid ammonia, and the precipitate colle€ted and dried. The fluid, from which this precipitate had been feparated, was evaporated, and the mafs ftrongly heated, fo as to vola- — tilize the muriate of ammonia that had been formed, when there remained two grains of falt, which being diffolved in | water, yielded cubical cryftals. Tbe precipitates ¢, The precipitate obtained by means of liquid ammonia d, ae car together with that before produced c, were put into a folu- tion of pot-ath, and digefted with that fluid. A folution was_ effeGted, and oxide of iron feparated, wohiaey after being igs nited, weighed 13 grains. f, The | ANALYSIS OF THE NATRGLITE. 1938 Ff. The alcaline folution e was mingled with muriatic acid, Alumine fepa- till the precipitate produced, became rediffolved, and was then prio aitens stale decompofed by carbonate of foda. The precipitate obtained after being wathed, dried, and ignited, weighed 242 grains, It was alumine. g. It remained ftill to examine the alcaline part of the foffil, The alcaline which produced with muriatic acid the 312 gr. c. and the — two grains d. Tafte, figure of cryftals, and chemical re- agents, proved it to be muriate of foda. A folution of it in water, mingled with a concentrated folution of tartareous acid, did not produce tartarite of potafh. Another part of the folution, after being decompofed by fulphuric acid, yielded fulphate of foda, Having afcertained by experiments that 100 parts of abfo« lutely pure carbonate of foda *, dried in a heat of ignition, when faturated with muriatic acid, loft 41 parts by weight of carbonic acid, and yielded 1204 parts of dry muriate of foda (the deficcation of which was not continued te decre- pitation) we may conclude, that the above 332 grains of mu- riate of foda contained 164 of foda. 100 parts of the natrolite confequently yielded : Component ‘. parts of natres Siliceous earth B. a ~ - +48. grs. lites Alumine - AFA fait, ws: ante LASS Oxide ofiron - e - ae ao: Soda~ + - g Die, 2 16550 Water .- A.’ a - - 99.50 The {mall number of foffils which contain foda, is therefore ‘augmented by one more. That foda was contained in this ftone might perhaps have been expeéted, on account of its forming frequently the matrix of the fonorous porphyry, which, __* In order to obtain perfeély pure carbonate of foda, I diffolve Pure carbonate _ common carbonate of foda in water, and faturate this folution ° 14% with nitric acid, taking care that the acid is a little in excefs. I : _ then feparate the fulphuric acid by nitrate of barytes, and the . muriatic acid by nitrate of filver. The fluid thus purified I eva- porate to drynefs, and fufe the nitrate of foda obtained, and decom- pofe it by detonation with charcoal. I then elixiviate the refidue, filter, and cryftalize the carbonate of foda. Vor. VI.—Novemser, 1803, O it 194 AEROSTATIC MACHINES. it is now known, always contains this alcali, but as the quan- tity of foda contained in this foffil, is twice as large as that which exifts in the fonorous porphyry, I have not hefitated at giving it the name of natrolite. Vi. On the Employment of Aerofiatic Machines in the Military Science, and for the Conftruétion of Geographical Plans.* By Citizen A. F. Lomer.t Prefent ftate of Tue acroftatic art is ftill in its infancy; and whatever pre- aeroftation, grefs may have been already, made in it, it is impoffible to forefee all the refources it may afford, or to determine the li- mits of its utility. Time and experience muft fix our opinions refpe€ting it; but it is of confequence to obtain the affiftance Its improvement of learned men and artifts in this interefting purfuit; and as the ma Ke ay {malleft inveftigations of this nature are generally too expen- werimnent. five for individuals, it is neceffary that the government fhould fupport an eftablifhment particularly devoted to the praétice and improvement of the proceffes which conftitute it. Advantages to Aeroftats will furnifh, in prefence of an enemy, one or be derived from more points of obfervation at pleafure, from which the pofi- its ufe in war. |. : ; , . tions he occupies may be reconnoitred, his movements ftudied, and his maneuvres judged of in the grofs, or appreciated in the moft minute detail. It may be prefumed that thefe ma- chines will become of the moft indifpenfable utility in war, be- caufe they fupply it with an extraordinary means, hitherto un- known, of making obfervations, which may in an inftant de- termine the fate of battles, fecure the difpofitions for a vigoroug defence, or at leaft point out the moment and the moft con- venient outlets for a retreat; and more particularly to draw at-- tention to the advantages which an army may derive from bal- Taftances loons, it will be fufficient to remember the happy ufe made of them at the battle of Fleurus. - * Adjutant-commandant, formerly keeper of the colleétion of models belonging to the Polytechnic School, and now at'the head of the fixth divifion of the war department. (Military operations and: movement of the troops.) t+ From Journal de l’Ecole Polytechnique, Tome 1V. p. 252. | The. “A®RostAtie MACHINES; 195 The Committee of Public Safety, and afterwards the Exe- Experiments -Cutive Directory, thought that the application of aeroftats to apa _ inilitary inquiries of every defcription ought to be ftudied and the French practifed during peace. They were alfo defirous, that they sovernments might be employed in the conftruétion of geographical plans, or at leaft in afcertaining the intermediate particulars of the territory between the points which had been geometrically de- termined. Having been charged with the experiments re- lative to thefe different applications, I purpofe giving an ac- count of the principal refults. The intention, from the firft afcents, was to meafure the Firft attempts at angle formed by the vifual rays falling on the eye of the aerial ane hae obferver, from feveral determinate points on the earth: The fual rayse unavoidable motion of the aeroftat preventing the ufe of the graphometer in this operation, a recipiangle was at firft fub- ftituted, fufpended like a mariner’s compafs, by the affiftance of which, it was hoped the meafure of the angles would be eafily taken, and particularly that they would be obtained with immediate relation toa horizontal plane. This attempt not having fucceeded, it was neceffary in future to make ufe of a fextant. This inffrument was every thing that could be defired for The ufe of the celerity, as well as for the facility aa precifion of the obfer- ee ea vations, but it has this inconvenience, in the cafe in hand, that it only fhews the angle ona plane inclined to the horizon; and moreover, in its ordinary confiruétion it furnifhes no means of noticing this inclination. The perpetual agitation of the ma« chine is another fource of error; in fa@, an aeroftat, kept eles vated and held by cords, is continually changing pofition; it. _ moves in fpace, defcribing alternate ellipfes, the curvature of which is modified to infinity, according to the violence of the wind, the elafticity of the cords, and the fituation of the places to which it isfaftened. It leaves then no trace of its variations, and does not permit the obferver which it fupports, to add to the meafure of any angle whatfoever, that of the two angles neceffary to conneét the firft with the plane of the horizon. _ Neverthelefs, for plans relative to the generality of military But is nevers inquiries, and in all cafes where a ketch of the figure of the aeee A gg earth is fufficient without attending to flight inaccuracies in cafes, diftances, fimple obfervations, made with the fextant, will anfwer the purpofe, and furnifh the means of operating with O2 facility 196 AEROSTATIC MACHINES. facility over a vaft extent of territory, fecure from the attempts. of anenemy. But it is not equally ferviceable in operations which require a rigorous exaétnefs, and in which it is requi- fite to conneét the angles with the centre of the ftation, and with the plan of the horizon. Additional ap- The following is the mode in which I have endeavoured to en Pap fulfil the various objeéts : capable of indiz The angles neceflary for conneéting the pofition of two ob- cating a// the re- jets with the centre of the ftation and the plane of the hori- quired angles. zon, are, lft. the angle comprehended between the rays fall- ing on the eye of the obferver from thefe points; 2d. the an- gles formed by each of thefe rays with the perpendicular.— We have feen, that it is impoflible for the aeroftatic obferver to mark thefe three angles by taking them after each other; but if their meafure were inflantaneous, the difficulty would be overcome. This would therefore be the cafe if an inftru-. ment could be devifed, which would give thefe three angles _at once bya fingle obfervation; and as the fextant already fhows the angle ‘oummatchendad between the rays, the objeét in view is to add the neceffary parts to that inftrument for ob- ‘taining the other two at the fame time. Preliminary ob- Let BAC (Plate X.) be the angle formed by the vifual rays fervations. AB, AC;; falling on the mirror A of the fextant from the ob- © jeGts B and C; if the index A Dbe moved until the image of the obje€&t C reflected by the mirror A placed on the index coincides by double refleétion on the mirror L, with the point where the obje& B is feen; and if they be both perceived at the fame time by the obferver looking through the telefcope P, itis known, (by the Theory and Ufe of the Sextant) it, That the angle D AE, comprifed between the index A D and the fixed radius or line of zero AE of the inftrument, is always equal half the angle BAC, the meafure of which is required: 2d, That the line R B, which is fuppofed to pafs through the axis of the telefcope and the centre of the mirror L, is always direGted to the point B, and is ufually taken for the fide A B; the error arifing from the {mall diftance A R being confidered as nothing in praétice: hence, if we fuppofe a vifual ray pafl- ing from the point R to the objeé&t C, the angles BRC and B AC may be reputed equal, and be taken indifcriminately for each other. This AEROSTATIC MACHINES. JOT This being premifed, if a ruler be placed in the dire€tion Method of af- RB, it may be confidered as in that of the fide AB, and eee eur ae if we can fucceed in fixing a fecond ruler in fuch a manner vifual rays.” that the moveable index fhall carry it into the dire@tion R C, at the infant that the images of the two objets B and C are brought into one at the point L, it is evident that thefe two rulers will form between them the angle BRC, and confe- quently the angle BAC. Toaccomplifh this, let us fuppofe a fort of falfe {quare, SR Q, fituate in the plane of the inftrument, and moveable at its axis on a pivot fixed at the point R, at the interfeétion of the lines ARand RL; making the angle SR Q, comprifed between its arms, equal to the anyle ER L, and the fide R S equal to the diftance AR. If now we fuppofe that the extremity S of the fide R S, is retained by a button ina groove M N, worked in the moveable index, the movement of it will be communicated to the falfe fquare in fuch a manner that the angle LR Q will always be equal to the angle B A C, and confequently the fide. R Q will be placed in the requifite direétion. In faét, the triangle ARS being ifofceles in its form, the exterior angle SRE=RAS+AER.= 2RAS=BAC; but SR Q being equal toE RL, if the common angle SRL be taken away, there will remain the angle S RE=LRQ= BAC. Now let us fix under each of the two rulers R L and Q R Obfervation of- a {mall graduated quadrant, fufpended in fuch a manner bbe ae that it will place itfelf in the vertical plane of the fide corref- yifual rays and ponding to the angle obferved; let us affix to each of thefe te perpen- quadrants a plummet, compofed of a ftiff arm moveable upon oe a pivot, and furnifhed with a nonius index and a weight, which gives it a conftant tendency to affume a vertical pofition, in whatfoever fituation the fextant may be placed; finally, let the whole be fo difpofed that the index of each plummet may be retained at will, at the divifion indicated on the limb by the effe&t of the fufpenfion, and this by means of a trigger, which can be pulled at the exaét inftant of obferving the principal ; angle in the points of reflexicn. It is evident that the fimul- shee cr ss taneous aétion of the two rulers and the plummets will fhow plane on the the three angles fought, and that nothing remains but to re- horizon are : btained b duce, by calculation, the angle B AC to the plane of the ho- calculation. rizon. This 198. Succefs of the inftrumente Probable future advantages. Method of con- neCting all the obferved angles in one com- mon centre. Application of the procefs. Inaccuracy to be expected from an inexperiened obferver, AEROSTATIC MACHINES. This inftrument, arranged in the manner here defcribed, produced every defired effeGt in our experiments. The irs vention, as fimple as it is happy, may become very important from the ufeful applications of which it is fufceptible; and there is already reafon to hope that, by bringing this to perfeétion, or bythe formation of fome analogous inftrument hereafter, there will be a poffibility of executing trigonometric operations- with much correétnefs, by the afliftance of aeroftatic machines, ° notwithftanding their continual motion, It was not enough to have difcovered the means of conneét= ing the angles with the plane of the horizon: it was ftill de- firable, that all the angles obferved during afcents in any one place, fhould have a relation to the common centre of obfer- vation. To accomplith this, it was neceffary to keep a regifter, by fome means, of the fituation of the machine at the precife moment of meafuring each of thefe angles. This was done by dropping from the aeroftat, at that inflant, a {mall flake, leaded and furnifhed with an iron point. This ftake fell rapidly to the earth, into which it ftuck, and marked a point correfponding to the fummit of the angle meafured. It was then eafy to compare the pofition of’this point, with that of one taken for the common centre of the obfervation, and thence to deduce the neceflary correétions, It muft however be noticed, that the ftake, when abandoned to itfelf, acquires, at the inftant of its fall, a compound motion which partakes of that of the aeroftat, and confequently is not exactly vertical; but the er- ror which refults from this deviation is but flightly perceptible in practice. The calculations and ordinary proceffes of defcriptive ge- ometry will furnifh all the means of making ule of thefe differ- ent obfervations, and of expreffing the refults on paper; not only for their application to the conftru@ion of maps, but alfo to afcertain heights compared with the level: but we {hall not in this place enter into any details on that head. The obferver engaged making thefe firft experiments, foon perceives that the involuntary embarraffment, occafioned by the novelty of his fituation, when he finds himfelf infulated and fufpended at a height of feven or eight hundred metres, has’ a confiderable influence both on the fidelity of his ob- fervations and. on the time neceffary for making them. All certainty depends, in faét, upon the confidence and readinefs of AEROSTATIC MACHINES. 199 ef the obferver; and it cannot be concealed, that it may produce great inconveniences, becaufe this difficulty of ope- rating opens wide limits for the errors which it is poffible to commit. | From this laft obfervation it will be feen: 1ft. That it is in- Conditions nee di{penfably neceffary to have acquireda great aptitude for thefe eefiary oe correét obfer- fort of obfervations, to be able to execute them with precifion : vations. 2d. That the proceffes juft defcribed are more fatisfaétory in theory than they would be in thofe applications which require ftrict accuracy; and, that though there are fituations in which nothing can be fubftituted for their ufe in the conftruc- tion of fome figured plans, it is at leaft proper never to ufe them in preference to thofe means of obfervation which are better known, and which can be employed with more cer- dainty. But it cannot be too often repeated, at the fame time, that Advantages to aeroftats furnifh the means of giving the moft lively intereft to ana aetie te the delineation of the figure of the earth, in maps of all de- joons in furvey- fcriptions; and that their ufe is of the greateft afliftance in the img countries. formation of plans, the outline of which may be fufficiently defined by a fimple eye-fketch. The aerial obferver, by difcovering a vaft extent of country, accuftoms himfelf fully to confider tle general organifation of the afperities of the country, and even the particulars of its varieties, as well as the tone of colour, which appear to give a different charac- ter to each portion of territory. If this new method of obfer- vation be cultivated with afliduity, it will doubtlefs lead to a fenfible improvement in the art ‘of drawing plans. But to be- nefit by the advantages which it affords, it 1s neceffary, that thofe who are deftined to this employment fhould join a pro- found knowledge of géometry to a great facility in defigning landfcapes. May they be convinced of the importance of this truth, and affure therafelves that no part of the plan can arrive at perfe@tion, either ornamental or relative to civil and mili- tary purpofes, unlefs ftri€t accuracy in the outline is accom- panied by that fidelity of expreffion which is capable of pro-~ ducing in thofe who infpeét the plans, all the ideas which the obferver had formed from the afpeé of the country. _’ From all that has been faid, we may conclude, that the aero- valuable pro- ftatic art combines properties no lefs valuable than unqueftionable At doe in topographic operations and military refearches; that its per- Bie fection hines. 200 pia ufe of eMe Scheele dif- covered an ine fizmmable ar- Seniated gas. Its properties. ARSENIATED HIDROGEN GAS. feétion may produce new and invaluable properties; and. that it would be equally impolitic to negleé the ufe of thefe ma- chines, or not to obtain for them the information to be derived from reflection and experience. We fhall terminate this me- moir by an obfervation relative to their military ufes. Our enemies would not fail to oppofe to the creative induftry of of France, an induftry of imitation: they would alfo have their balloons and ballooneers (ueroftiers.) The influence of this innovation in war is of a nature to fpread with. rapidity, and it muft foon ceafe to favour any nation exclufively. But even in this cafe the art of aeroftatic machines will have acquired a higher degree of intereft, becaufe another element fhall then be in the power of man, in which the efforts of genius and . induftry may be fubftituted inftead of the inconfiderate devafta- tions of force; and this obfervation ought to intereft the friends of hu-manity in bringing them to perfection. Vi. Chemical Analyfis and Properties of Arfeniated Hidrogen Gas By Proressor TROMSDORFF.* "THE immortal Scheele, in his effay on arfenic and arfenic acid,t mentions an inflammable arfeniated gazeous fluid, of which he fays: ‘¢ Hine intelligas, hunc aerem inflammabilem eff, regulumque arfenict folutum tenere.” Scheele ftates, that he ob- tained this gas during the folution of tin in arfenicacid. The properties of this gas, as pointed out by him, are the follow- ing. Arfeniated hidrogen gas is infoluble in water; it does not render lime-water turbid; mingled with atmofpheric air, no diminution of bulk enfues; on bringing the flame of a taper in contaét with this mixture, a loud detonation follows, and metallic arfenic is depofited. Interefting as the obfervations here pointed out muft appear to every chemift, the obje& has been negleéted by fucceeding operators. * From a memoir, read in the Royal Academy of Sciences at Berlin, 1803, p. 370. + C.H. Scheele Om Arfenick och defs Syra; Kongl. Svenkk. Vetenfkaps Academiens Handlingar. Ar. 1775. V. xxxvi. 265. Prouft ARSENIATED HIDROGEN GAS. 201 Prouft is the only philofopher who mentions this gas: * he Prouft mentions obtained it by digefting arfenious acid and zinc, in dilute ful- its phuric acid ; on burning the gas, he obtained fometimes arfe- nious, at.others arfenic acid. Being perfuaded that the for- mation and properties of this gas deferved a clofer examination, I inftituted a feries of experiments, the refults of which are as follows. Methods of obtaining urfeniated Hidrogen Gas. 1. There are a variety of proceffes for obtaining arfeniated Proceffes for ob. » nidrogen. It is produced by heating tin filings in liquid arfe- ame nic acid. This method is the moft expenfive and moft tedious. gas. During the evolution of the gas in this procefs, arfenic, al- loyed with tin, is precipitated, and the fluid obtained, holds in folution, arfeniate of tin. 2. It is likewife formed by treating ina fimilar manner, arfe- nic and iron with muriatic acid. 3. Arfeniated hidrogen is alfo produced by heating a mix- ture of arfenious acid, iron filings and muriatic acid. The fluid, in this cafe, contains muriate of iron and muriate of arfenic. 4. Tin filings and arfenic acid yield this gas under fimilar circumftances. 5. Four parts of granulated zinc and one of arfenic, treated : in a fimilar manner with fulphuric acid, previoufly diluted with two parts of water, afford arfeniated hidrogen very readily. The gas obtained according to either ar thefe proceffes, is Beft produced nearly alike, but that produced according to the laft procefs sree feems to be the moft perfeét gas, for it contains no excefs of fulphuric acid. hidrogen. When arfeniated hidrogen is produced by means of zinc, arfenic, and dilute of fulphuric acid, the quantity of arfeniated hidrogen is lefs than the quantity of hidrogen which would be obtained in decompofing water in a fimilar manner, without the interpofition of arfenic. The refidue, after the evolution of the gas has ceafed, contains metallic arfe- nic; part of the hidrogen muft therefore have aéted on the oxigen of the arfenic acid, in order to reduce it to the metal- - jie ftate. From what has been ftated, it appears that arfeni- ated hidrogen contains arfenic in a metallic ftate, and not in the ftate of arfenious, or arfenic acid. This will become more _ obvious in the fequel of this paper. : * Journ. de Phys, T. II. p. 173. Phyfical 202 ARSENIATED HIDROGEN GAS. Phyfical Properties of Arfeniated Hidrogen Gas. Its phyfical proe Arfeniated hidrogen is a permanent elaftic aeriform invifible pesties. Its chemijcal properties. Mixed with nie Prous £ase With oxiginized muriatic acid gas. fluid. It is a trae chemical compound. Prouft afferts that it depofits arfenic: This however I have never been able to ob- ferve, if the gas were pure. It has an alliaceous fetid fmell. It extinguifhes burning bodies. It is not abforbable by water; but when this fluid is freed from atmofpheric air, it takes up a {mall quantity of the gas which becomes difengaged again by mere agitation. It does not change the colour of tinéture of litmus. The fpecific gravity of arfeniated hidrogen is, at 28° barometrical preffure = 0,5293, or, one cubic inch fold French meafure) weighs 0,2435 grains. It is therefore lighter than oxigen, nitrogen, atmofpheric air, carbonic acid, nitrous gas, ammonia, and gazeous oxide of carbon, but heavier than hi- drogen and fulphurated hidrogen gafes. It is abfolutely fatal to animal life, Chemical Properties of Arfeniaied Hidrogen Gas, Arfeniated hidrogen, mingled with atmofpheric air, fuffers no chemical change, but meredilution. The fameholds good with refpe@ to nitrogen. When mingled with nitrous gas, a diminution of 0,02, or 0,03 takes place, which fometimes even amounts to0,05. To afcertain the nature of this gas, I mixed two parts of arfeniated hidrogen, with one of nitrous gas, and gradually added oxigen, till no further diminution of bulk en- fued. On prefenting to this mixture a lighted taper, a loud explofion took place, accompanied with flame. Probably part. of the oxigen added, remained uncombined; for a mixture of two parts of nitrous gas, and three of arfeniated hidrogen, could not be inflamed by the taper; arfeniated hidrogen is, mifceable with hidrogen, with carbonic acid, and with ammo- nia in all proportions. Into acylinder half filled with arfenic and hidrogen, I fent up bubbles of oxiginized muriatic acid gas. The bulk of the gas was diminifhed, heat was evolved, and metallic arfenic was depofited in a cryftalline ftate. On adding to the mixture an additional dofe of oxiginized muriatic acid gas, white fumes appeared, and the depofited metal vanifhed. The fame ex- periment was repeated fucceflively, taking care toadd no more of the latter gas, than was juft {ufficient to occafion the pre. cipitation & ARSENIATED HIDROGEN GAS, 208 cipitation of metallic arfenic. The colleQ@ed metal yielded nitrous gas, by the affufion of nitric acid, and on adding to this mixture muriatic acid, arfenie acid was produced. The arfenic depofited in the manner ftated before, when laid on ignited coals, became volatitized in thick white fumes, yield- ing arfenious acid. The precipitation of metallic arfenic muft be afcribed to the decompofition of the oxiginized muriatic acid gas; the oxigen of this gas uniling with part of the hidrogen of the arfeniated hidrogen, and forming water, and thus fe- parating the arfenic. For the arfenic is capable of being ox- ided by the muriaticacid. Should it be imagined, that arfenic exifted in arfeniated hidrogen, in the oxidized ftate, and that it became precipitated by the oxiginized muriatic acid robbing it of its oxigen, we fuppofe things analogically erroneous, for the oxiginized muriatic acid is more capable of giving cut oxi- gen than of taking it. The experiments of Chenevix feems perhaps hoftile to this affertion; but the experiments of this philofopher merely prove that the oxiginized muriatic acid is capable of combining with an additional dofe of oxigen, and conttituting with it a hyperoxiginized muriatic acid, This ~ certainly cannot be the cafe in the prefent inftance, as will appear more evident from what I fhall {tate prefently. J filled a cylinder in the mercurial pneumatic trough, with Further experi« arfeniated hidrogen, and fent up into it as expeditioufly as pof- ents with this fible, a quantity of oxiginized muriatic acid gas. The refult ela ict was evolution of heat, diminution of volume, and the inner _ fides of the cylinder became covered with a kind of dew. A formation of water had therefore a¢tually taken place in this experiment. Into another dry cylinder half filled over mer- cury, with arfeniated hidrogen, I introduced dry muriatic acid gas. In this cafe no diminution of bulk, no feparation of arfenic enfued; no changeat all took place. Repeating the fame experiment, I introduced into the cylinder a fmall quan- tity of water; the muriaticacid gas was abforbed, and the re- _ fidue was arfeniated hidrogen unaltered. Into a cylinder half filled with oxiginized muriatic acid gas, I paffed gradually arfeniated hidrogen in fmall bubbles at a _ time; in this cafe no metallic arfenic was feparated, but thick white clouds appeared. On continuing the addition of arfes Miated hidrogen till no more white fumes appeared, metallic arfenic was depofited, Jt follows from this experiment, that when 904 ARSENIATED HIDROGEN GAS. when a fall quantity of arfeniated hidrogen is made to act upon a large quantity of oxiginized muriatic acid gas, part of ihe oxigen of the oxiginized muriatic acid gas combines, not only with the hidrogen of the arfeniated gas, and forms water, but the metallic arfenic alfo becomes oxidifed. Reafoning from this faét, we fhould be inclined to believe, that a mutual de- compofition of both the gafes could be thus effeéted; but this camot be accomplifhed; a diminution of bulk indeed takes place to a certain extent, but the complete difappearance of both the gafes cannot be effe€ted. If the admixture of arfe- niated hidrugen, with this oxiginized muriatic acid gas, be continued no longer than white clouds appear, and the refidue be then examined, it will be found to confift of hidrogen and oxiginized muriatic acid gafes; and the mixture detonates at the approach of a taper. The oxiginized muriatic acid gas- can only be feparated with difficulty by long agitation, in con- taét with water, andit feems as if it were become lefs foluble in that fluid. If the feparation of this gas be accomplifhed, the remaining arfeniated hidrogen burns with a pure flame, void of alliaceous odour, and contains no veftige of arfenic, as fhall be proved hereafter. From what has been ftated, the following theory may be formed. Theory of the Arfenic, in combination witha certain portion of hidrogen, decompofition of conftitutes arfeniated hidrogen gas. On prefenting to this asfeniated hidto- — 4 bination oxiginized muriatic acid gas, the oxigen of this rite! gas combines with the hidrogen, which held in folution the arfenic, and the latter is feparated. If more oxiginized mu- riatic acid be added than is neceflary for this purpofe, the por- tion of oxiginized muriatic acid gas does not aét further upon the hidrogen, but merely upon the arfenic, and the latter be- comes oxidifed. Arfeniated hi- Hidrogen and arfeniated hidrogen may be mingled without drogen gas MiX* Jecompofing each other; the decompo.-tion can only be ef- ed with hidro - C “ : gen. feéted by the contaét of fire; but if we mingle hidrogen, hold- ing in folution fulpbur and-oxiginized muriatic acid gas, the decompofition and formation of water is inftantly effected. This is likewife the cafe with arfeniated hidrogen gas. Hidrogencom- Hitheriono combination of hidrogen with a metallic fubftance bined with me- has been known; but it is highly probable, that fach combinae tallic fubftances. . 2 ar 3 tions may exift. This indeed feems to be the cafe in the for- mation of this gas on which we are treating. » If this be ad- 4 - mitted, ARSENIATED HIDROGEN GAS, 905 i mitted, a divifion of hidrogen muft take place, in the follow- ing manner; one part of it muft unite with the oxigen of the oxiginized muriatic acid gas, to produce water; another part muft fall down with the arfenic; and another portion remains combined with caloric, in the form of hidrogen gas. Hydrothian acid gas * and arfeniated hidrogen do not aé Sulodiordees and upon each other. Toa mixture of equal parts of hydrot Te ar aia acid gas, and arfeniated hidrogen gas, I added gradually Qx- Oxiginized mu- iginized muriatic acid §233 a diminution of volume inftantly ae pee took place, accompanied with liberation of heat, and a depo-- NEE fition of yellow fulphurized arfenic (orpiment). On adding an additional quantity of gas, the precipitate acquired a beau- tiful orange red colour, and on continuing the addition of ox- iginized muriatic acid gas, white clouds were produced, the precipitate detached itfelf from the fides of the veffel, and were gradually converted into a pulverulent lnbitance ofa yel- lowith white colour. The refults of ‘thefe experiments are obvious, and might Teft of arfeni- have been expeéted a priori. But they may ferve asa teft to #4 hidrogen. difcover the prefence of arfeniated hidrogen, when contained in other gafes, | I mingled one cubic inch of arfeniated hidrogen with ten of Nitrogen mixed © "nitrogen, and one of hydrothian acid (fulphurated hidrogen With it. gas;) on adding to this mixture a {mall quantity of oxiginized _ muriaticacid gas, yellow fulphurized arfenic was inftantly de- pofited. It is not improbable, that arfenic is likewife foluble in other gafes, and in this cafe the hydrothian acid (liquid ful- phurated hidrogen,) in conjunétion with oxiginized muriatic __ acid, would provea ufeful re-agent for difcovering the prefence of it. A lighted taper immerfed ina vial filled with arfeniated hi- es 2 _ drogen, is inftantly extinguifhed; at the fame time that the mo niet’ _ gas burns at the orifice of the vial with a lambent white flame, diffufing a difagreeable odour, and much white fumes, which are arfenious acid. If the gas be inflamed in a phial with a {mall orifice, the flame defcends gradually down to the bottom of the phial, which becomes lined with a coat of cryftallized In this cafe therefore the hidrogen alone / metallic arfenic.. _ burns. _* The name given by the Germans to fulphurated hidrogen gas, on account of its pofleffing the properties of an acid. If 9206 Explodes with oxigen. Burns beauti« fully in oxigen Fase Compofed of me- tallic arfenic and hidrogen. Its habitudes to acids. Concentrated nitric acid. ARSENIATED HIDROGEN GAS: If two parts of arfeniated hidrogen be mingled with thre of dxigen, anda taper be prefented to the mixture, an ex .plofion takes place; no metallic arfenic is feparated, but the produ@ts are arfenious acid and water: foap-bubbles with the mixture of thefe gafes, explode with a bluifh white flame, leaving a white {moke and ftrong alliaceous odour. Equal parts of arfeniated hidrogen and oxigen gafes, fired in like manner, do not explode fo loudly, but the report is accompa- nied with a much more vivid flame.’ A ftream of arfeniated hidrogen, iffuing from a bladder fitted with a ftop-cock, and fet to burn in a large receiver filled with oxigen, yielded arfenic acid. The combuftion in this manner is uncommonly beautiful; the gas burns with a blue flame of uncommon fplendor: Two parts of arfeniated hidrogen, and one ofoxigen gas, being detonated in a clofe veffel by means of the ele@tric {park, left a fmall refiduum; on repeating the experiment, the deto- nating tube broke during the explofion, which prevented the examination of the refidue. From what has been fo far re- lated, it becomes evident that the conftituent parts of aFles niated hidregen gas, are metallic arfenic and hidrogen. Were it poflible to determine with abfolute certainty, that no ins creafe of volume took place during the folution of arfenic in hidrogen, ‘the proportion of the conftituent parts of this gas might be afcertained thus : | French weight and meafure. One cubic inch of hidrogen, weighs - 0,0353 One cubic inch of arfeniated hidrogen, weighs 0,2435 Deduéting the former from the latier, we get 0,2082 Which is the quantity of arfenic diffoived in the gas, confes quentiy one cubic imch of arfeniated hidrogen gas, confifts of 0,0363 hidrogen, and 0,2082 arfenic ; and one cubic inch of this gas contains about 4 grain of metallic arfenic. Habitudes of arfeniated Hidrogen to Acids. Into a phial, containing about eight cubic inches of ar+- feniated hidrogen, I Boarea a half cine inch of concentrated nitric acid. The moment the acid came into contact with the gas. ARSENIATED HIDROGEN GAS. 907 gas. The phial was filled with denfe red fumes, a white flame pervaded the veffel, and a‘detonation enfued. On repeating the experiment with dilute nitric acid, no pilure nitric accenfion took place. The refiduary gas was pure hidrogen, “id. and the water contained arfenic acid. Fuming concentrated nitrous acid therefore is capable of oxidifing the arfenic con- tained in this gas, at the fame time that the oxigen of the acid burns with the hidrogen of the gas, and produces water ; whereas weak nitric acid is only capable of oxidizing the are fenic, without ating upon the hidrogen prefent. Into.a glafs tube, furnifhed with a ftopper at one extre- Nitro-muriatie mity, and clofed at the other, I introduced eight cubic aid. inches of arfeniated hidrogen, to which were added two cubic inches of nitro-muriatic acid. After having agitated the _ fluids, on opening the tube under water, a diminution of one cubic inch took place. The refiduary gas was pure hidrogen. it isremarkable that, during the addition of the nitro-muriatic acid, a black powder feparated, which again difappeared on agitating the tube. Nitro-muriatic acid aéts therefore in the fame manner upon this gas, as oxigenized muriatic acid gas. It effects firft a feparation of the metallic arfenic, and then oxiginizes this metal. Liquid oxigenized muriatic acid: de- Oxiginized mus compofes arfeniated hidrogen by mere agitation; the refidue "tic acid. is hidrogen. Muriatic acid exercifes very little aGtion upon Mutiatic acide arfeniated hidrogen ; but merely diffolves a minute portion of it, which may be expelled again by heat. Concentrated Concentrated 2 . : : acetic acid. acetic acid has no effect upon it. Into a glafs cylinder holding eight cubic inches of arfe- Concentrated niated hidrogen, I poured one cubic inch of concentrated ful- fulphuric acide phuric acid, and then clofed the tube. At the moment of the addition of the acid, the cylinder became lined with a coat cyrious phenoe of bright metallic arfenic, fo as to refemble a looking-glafs, menon. On agitating the cylinder, the coating refolved itfelf intoa _ brownifh black powder, which, after a few days, aflumed the colour of Kermes mineral. On opening the cylinder un- _ der water, a diminution of bulk enfued, and the refiduary _ gas proved to be hidrogen. The experiment was repeated, and yielded the fame refults. The fulphuric acid employed The fulphuria in this experiment, had acquired a penetrating pungent fmell, acid examined. and was examined, after having been neutralized by am- -monia, in the following manner : 5 Ammo- 208 ARSINEATED HIDROGEN GAS, Ammoniate of copper, on being mingled with it, acquired: a greenifh colour. Hydrofulphuret of ammonia inftantly oc- cafioned a copious yellow’ precipitate. Water impregnated with fulphurafed hidrogen gas, occa- fioned a fimilar effe@t.. From the refults of thefe tefts it be- comes obvious, that the acid confifted of fulphuric, ful- phureous and. arfenic acid. In order to be certain in this refpect, I. mingled a few. drops of liquid arfenic acid with a mixture of fulphuric and: fulphureous acid, neutralized the fluid: with ammonia, and fubmitted it to the fame tefis. The Rheory. refults of this mixture were analogous to the former. The decompofition of the arfeniated hidrogen gas, is probably analagous to the decompofition of this gas, by means of oxiginized muriaticacid gas... The fulphuric acid firft gives ap part of its oxigen to the hidrogen‘of the arfeniated gas, and occafions the feparation of the arfenic.; which, at the ex- pence of the remaining portion of oxigen of the fulphuric acid, becomes afterwards onigeiiae, and conftitutes the arfenic acid. Itchabitudes Habitudes of arfeniated Hydrogen Gas to Metallic Solutions. to metallic Mima uss atucey ian lL caufed a current of arfeniated hidrogen gas, to pafs through: Ammoniate of 4 (olution of ammoniate of copper. , A metallic pellicle ap- eae: peared on the furface of the fluid, which fuffered no other change. Muriate of tin. Into a botile filled with arfeniaia hidrogen gas, I dropped a folution of muriate of tin, On agitating the folution, it ac- quired a brown colour, a partial diminution of the gas en- fued, but the folution of tin was not converted into an oxi- _ dized muriate of tin, which would have been the cafe, if . the arfenic exifted in the gas in an oxidized ftate. Nitrate of lead. | Nitrate of lead, on being brought into contaét with ar- feniated hidrogen gas, became turbid; and: ao a preci- pitate, which was arfeniate of lead. Nitrate of filver. Nitrate of filver fubmitted to the action of, the gas, became inftantly of an intenfe black, and a pellicle of metallic filver — . colleéted on the furface of the fluid. The refidue of the gas, which had been made to aét on the oxide: of' filver for fome time, had all the properties of pure hidrogen.- A good teft. This experiment fhows, that nitrate of filver might be em- ployed for deteéting the prefence of arfeniated hidrogen ; for as ARSENIATED HIDROGEN GAS, 2999 ss long asa minute quantity of arfenic was prefent, a black precipitate enfued; whereas pure hidrogen has no effeét upon this re-agent. I paffed into a concentrated folution of nitrate of filver, a fiream of arfeniated hidrogen, collected the black metallic _precipitate, wafhed and dried it: The fluid obtained in this procefs did not difturb the tranfparency, or change the co- lour of ammoniate of copper. Neither liquid fulphurated hidrogen, tinGiure of galls, nor potafh, had any effeét upon it. It contained therefore neither filver nor arfenic. The precipitate before obtained, acquired a metallic luftre on be- ing faturated ; laid on ignited coals, it diffufed an odour of arfenic, and it yielded by fufion a button of filver. It was an arfeniate of filver. . Arfeniated hidrogen paffed into a folution of nitro-muriate Nitro-muriate of gold, occafioned a precipitate; on the furface of the of sold fluid appeared a pellicle of metallic gold; and the fides of the veffel, in contact with the fluid, became beautifully gilded. The fluid through which the gas had been pafled, examined in the ufual manner, proved to contain no veftige either of gold orarfenic. ‘The precipitate greatly refembled _ charcoal duft, interfperfed with minute particles of gold. It is highly probable, that arfeniated hidrogen is capable of Decompofes mes decompofing all metallic folutions, the bafis of which is either tallic folutionse nitric, or muriatic acid, and probably other acids. Habitudes of arfeniated Hidrogen Gas to various other Bodies. Expreffed oils, on being agitated for fome time in contaét Its habitudes with arfeniated hidrogen, abforbed part of the gas, and ac- © ee _ quired a deeper colour. Alcohol fuffers no change from arfeniated hidrogen, Solu- andto alcohols tion of potafh, and liquid ammonia, do not abforb it. andealcditete . Such are the properties of this gas, the inveftigation of which I fhall continue as foon as my health is reftored, it be- ing fo confiderably injured by the unavoidable inhalation of this gas during the courfe of thefe experiments, which gives me ample reafon to conclude, that the gas muft be highly poifonous. ) D. J. B. TROMSDORFF. Enfurth, Feb. 1803. Vor, VI.—NovemBeER, 1803, r Account Dr. Hope’s eu- diometric appa- yatus. KUDEIOMETRIC APPARATUS. VII. Account of an Eudiometric Apparatus, contrived and ufed by Dr. Horr, Profeffor of Chemifiry in the Univerfity of Edin- burgh*. SINCE the difcovery of the uncertainty with which the application of nitrous gas to atmofpheric air, and other mix- tures, containing oxigen is attended, it has been found de- firable to prefent folid or liquid fubftances for the abforption of that principle. This, on firft confideration, may feem at leaft as eafy to be done, as to mix two gafes ; but it is by no means fo, becaufe the liquids in particular poflefs a degree of chemical a€tivity, which renders it inconvenient to im- merfe the hands in them, or to expofe their furfaces to the open air, efpecially when it is attempted to accelerate their Operation by means of agitation, fo as to obviate the prin- cipal objeétion to their ufe, the tardinefs of the procefs. - The apparatus of Dr. Hope, which he ufes in his leétures and in his experiments, is at once fimple aud effectual, and I have the pleafure of inferting the following correét enone tion with his permiffion. The apparatus confifts of two bottles, which are repre- fented in Plate XII, conneéted together in the manner in which they are ufed; A reprefents a fmall bottle which may be nearly two inches in external diameter, and three in length, ' having a neck and ftopper at D, and another neck as ufual at C. It isdeftined to contain the eudiometric liquor. Brepre- fents a larger bottle, which may be nearly of the fame dia- meter, or rather of {omewhat lefs, but 82 inches long. The neck of B is fitted accurately by grinding into the neck of AatC. The method of ufing this apparatus is very fimple: intro- duce in the ordinary ‘way into the bottle B, the air or gas * As the defcription at p. 61, of the prefent volume is in fome sefpeéts inaccurate through hafte, and the figure, being an outline, appears as if the neck of the upper veffel protruded fo far into the lower, as to prevent the afcent of a portion of the gas after agi- tation,—I have chofen rather to give an entire defcripticn and drawing in this place, than adopt the lefs acceptable procefs of an- gotating and correcting. til ZUDIOMETRIC APPARATUS. 911 ill it is full; then fill A with the abforbing liquor, for exam- Dr. Hope’s eu- : a 3 : : diometric appa ple with a folution of fulphuret of lime, which Dr. Hope jatys, ‘commonly employs, and covering the mouth with a flat piece of glafs, plunge it under the furface of water, and there in- fert the neck of B. The compound veffel is then removed from the water, and inclined till a fufficient quantity of the liquor flows into B. It is now well fhaken, and the agitation ought to be con- tinued till the abforption is compleated—Left the diminution of the denfity, of the included elaftic fluid fhould retard the abforption of the oxigenous portion; from time to time the apparatus, in the pofition in which it is reprefented in the figure, is to be placed ina plate full of water, and the ftopper D is to be loofened, or fo far withdrawn, as to allow this fluid to enter to fill the place of the abforbed gas.—By this admixture of water the liquor is diluted, but not to fuch a degree as in any meafure to interrupt the advancement of the procefs, unlefs indeed when the gas abounds very much in oxigen. When a gas of this defcription is the fubje& of experiment, it may be proper to ufe an apparatus, of which the bottle A is made of greater capacity in relation to the fize of B, than in the proportion already affigned. As foon as it is obferved, that after reiterated agitation, and opening the ftopper D, the liquor does not rife higher, the ab- forption may be confidered as compleated, and the operation may be finifhed by allowing the inftrument to regain its ori- ginal temperature, in cafe, from want of due precaution, it _ may have been affected in this refpeét by the warmth of the hand in the courfe of the experiments. If the bottle B be graduated, the amount of the abforption may be determined at once, by plunging the apparatus into water to the level of the included liquid, and removing the ftopper, otherwife the refidual gas may be transferred into a tube, exprefsly graduated for meafuring gafes. - By this convenient contrivance, we fee that the liquid is ~economized and the celerity, neatnefs, and precifion of ex- periment are enfured. The fize here mentioned is very well adapted to the purpofes of publie exhibition, but it is almoft ~ needlefs to remark, that it may, and in general ought to be made confiderably fmaller for the ordinary eudiometric expe- riments. F:2 Dr, 219 Apparatus for drying precipi- tates on the water bath ; APPARATUS FOR DRYING Dr. Hope fuggefted that the apparatus might be made ftitt more fimple without impairing its merits, in any confiderable degree, particularly when fmall volumes of gas are to be ex- amined, This is done by ufing a {mall bottle having one neck only, and having a graduated tube nine or ten inches long, and from half to three quarters of an inch in diameter, accurately adjufted to fit into it, but not projecting into its cavity. If the bottle have twice or thrice the capacity of the tube, the fame folution of fulphuret of lime may be repeatedly ufed, and the abforption will be more expeditious. In employing this inftrument, the manipulation is in all refpeGts the fame as above defcribed, excepting when the progrefs or termination of the operation is to be difcovered. . For this purpofe, loofen the conneétion between the tube and the bottle, in a degree fufficient to allow the ingrefs of the water of the trough, in which the eudiometer muft then be immerfed. This apparatus equally unites difpatch, coeconomy of eudio~ metric liquor, and convenience of management. IX. Defcription of an Apparatus for drying the Produéts of Chemical Analyfis which is alfo ufeful for Experiments of Congelation. By Mr, FrepertcK Accum. Communicated by the In- ventor. "Tuts apparatus, Plate X. is extremely ufeful in drying fuch produéts as abfolutely require a temperature not exceed- ing 212°; fuch as fulminating mercury, Chenevix’s fulminat- ing filver, and other explofive compounds. The fubftance to be dried muft be placed in the conical glafs veffel B, and when the veffel F is filled with water up to the fide tube D; the deficcation may be performed without any rifk of ex- plofion, or any further trouble, by putting the apparatus over alamp, and keeping the water in a ftate of ebullition. (See the lower drawing in perfpective.) I have found it particularly ufeful in the deficcation of the precipitates obtained in the analyfis of minerals, Itis well known that the fame mineral, analyfed CHEMICAL ANALYSIS, 913 analyfed by different chemifts, has been found to yield dif ferent proportions of the fame ingrediants, and that the difference of proportions of the conftituent parts, in many cafes, is often more apparent, than real; arifing entirely "from the various degrees of deficcation that has been employed by different analy{ts, and fometimes even by the fame perfon. This point is of fuch importance, and is productive of fo much trouble, that every chemift who has analyzed a mineral water, or cryftallized and feparated {mall quantities of deli- quefcent falts, will at once perceive the utility of the ap- paratus in this re{pect. This apparatus may likewife be ufed as a water-bath. In The fame ufed that cafe, the conical glafs veffel B is removed, and the inner 4S 4 water bath tin velfel E filled with water ; into this, retorts, flaiks, galli- pots, vials, bottles, &c. may be immerfed for promoting the proceffes of diftillation, digeftion, folution, evaporation, &c. é or it may be ufed asa fund bath, (it being hard foldered) by or fand bath. . filling the tin veffel with fifted fand, for performing thofe operations which require a higher temperature, than that of boiling water. When the inflrument is required to be ufed as a freez ing Method of freez~ apparatus, the bottom cover G is to be taken off, and the Hes (mercury for example)’ by cavity between the interior, and exterior veffel, filled with PRR 62S the frigorific mixture ; a wetted piece of bladder is then to be tied over the opening, or the cover is put on, to retain the mixture. The fecond frigorific material (for inftance if quickfilver is to be frozen) confifting we wil fay, of muriate - of lime and fnow, are to be cooled by the mixture in the exterior veffel, by putting the muriate of lime into the conical glafs veffel, together with the mercury contained in a thin glafs tube; and furrounding the glafs veffel, by filling the interior tin veffel with fnow, or pulverized ice. When thefe ‘materials have been cooled down to 0°; the fnow and ice may be mixed together by emptying the muriate of lime into the veffel containing the fnow, and ftirring the mixture with a glafs rod to facilitate the folution of the falt, and to produce the requifite degree of cold. The number of apparatus I have fold to philofophical chemifts, gives me reafon to fuppofe, that they have proved ufeful. FREDERICK ACCUM. 11, Old Compton Street, Soho. Letter 914 PROCESS FOR OBTAINING THE AGUSTINE EARTH. xX. Letter from Mr. Accum, in anjwer to the Enquiries of a Cor- refpondent refpeciing the Procefis for obtaining the Agufiine Earih. To Mr. NICHOLSON, ° DEAR SIR, Miftake refpe&t- Your correfpondent, P. O. in the laft number of your ing the publics: Journal, is correé&t, when he obferves, that the procefs for tion of the ase é 4 ; : method of ob- obtaining aguftine earth is not noticed in my fyftem of prac~ taining a8%s= tical chemiftry, nor in any other work publifhed in this coun- tine earth. iry, and alfo that moft of the books he quotes, were pub- lifhed a confiderable time after this earth was made known by profeffor Tromsdorf; but he is miftaken in his opinion, that it was known in this country previous to the publication of the above works. Firft account. The method of feparating this earth from the mineral which contains it, had not then been communicated to us through ~ the ufual channels of fcientific information. - The firft account of the method of feparating this earth I can find, is contained in agerman work, entitled Prediijche Anleitung zur zerlegenden Chiemie, publifhed by Profeffor Géetling, 1802. From which the following tranflation is made. oS ee Let a determinate quantity of the Saxon beril finely levi- pieces, boiled gated, be boiled in a filver vellel, with three or four times its with potah; weight of potath, diffplved ina fufficient quantity of water ; sie Oe evaporate the whole to drynefs, and fufe the mals. aR aN Soften the alcaline mafs by the gradual addition of water, ees as and when detached from the crucible, add to it muriatic acid . evaporated to till the whole is diffolved. Evaporate the folution to drynefs, with waers and Boil. the mafs in-a fufficient quantity of water, and feparate the filex fepa- the infoluble refidue [filex ] by the filtre. Bees ie Decompofe the fluid from which the filiceous earth has been cipitated by car-feparated, by gradually mingling it with a folution of car- bonate of foca; bonate of foda; colleét the precipitate, and wath it re- peatedly. feparate the When the precipitate obtained in the laft procefs has amapune too) acquired fome confiftence, transfer it into a flafk containing the precipitate , ; i by potath whicha concentrated folution of potafh, The alumine which was. diffolves it and i e1e Jeaves the agus pr fent- tine carthe METHOD FOR CLOSING WIDE MOUTHED VESSELS, 916 prefent in the mineral, will be diffolved*, and the infoluble refidue left, is the new earth called Agufine. It is diftinguifhed from all other earths by being teddy Charaéters of iMfoluble in potafh, foda, and ammonia, and all their car- this earth. bonates. Nor can an union of either of the two firft al- calies with Aguftine be effected by fufion, It is foluble in acids, with which it forms falts, which have little or no tafte, It is foluble in acids with equal facility after having been ig- nited, as when frefh prepared. It fufes with borax into a tranfparent colourlefs glafs. 100 parts of the Saxon beril yielded Profeffor Trom(dosf 78,0 Aguftine, 4,5 alumine, and 15,0 filex. lam, Sir, Your moft obedient, FREDERICK ACCUM, 11, Old Compion Street, Soho, 15th Odober, 1803. a er ee ae ee XI. Letter Jrom a Correfpondent concerning the Method propofed by Mr. Carlifle for clofing wide-mouthed Veffels. Odtober 15, 1803. STR, In the laft number of your Journal, publifhed on the firft of The method of this month, page 68, I find a letter addreffled to you by Mr. te uetehs uggefted in our Carlifle, defcribing ‘ more advantageous in chimnies on fire, than the fhocking procefs of fending up a child wrapped in rags to’ entet an a@ual place of combuftion and fuffocating vapour. Plate XII. Fig. 1. reprefents an apparatus of brufhes, fup- ' pofe four, which are fixed by hinges to a middle. piece or bar, | fe 3 256 Machine for clearing chime nies. MACHINE FOR CLEANING CHIMNIES, fo that they thall be capable either of hanging down, parallel to the bar, or of being opened and expanded, fomewhat in the manner of an umbrella, until they ftand out at right angles with the middle piece; in which fituation they are retained by fmall fupporting bars, refembling thofe of the fame well- known utenfil. Fig. 2. fhews the bruthes in their collapfed ftate, with an appendage of tubes, by which the fyftem is thruft up the chimney. $0:"000 If we divide thefe again, they become, ‘ Force at 32° = »200 inch. 2-17 542 = 9435 2. a9 The = 3910 i i ae Oe 592 = 3. a0" ~ 1, 92 122 = 33 500 Ratios, achat ‘1. 84 ar 1442 = 6. 450 ; - ee ges Yor = 11. 250 . ae) Se i | 1893 = 18. 800 ; et The Ser 212 = 30, 000 FORCE OF VAPOUR, 298 By another divifion we obtain the ratios for every 13° of Examination of temperature from 32° to 212°, as under : the progreffion of the force of Force at 32° = 3200° inch vapour. 1. 485 43% = 297 1. 465 542 = 4435 I, 45 652= 630 1, 44 Oe 3910 1. 43 8382 1. 290 I, 41 991 1. 820 1, 40 4102 = 2. 540 i 3s 122 = 3. 500 Ratios, 1. 36 133} 4. 760 lL. 35 _ 1442 = 6, 450 1. 33 15h 48. 550 1. 32 LORS (asm). 250 i. 30 178% = 14. 600 1: 29 1892 = 18. 800 Ly QF I, 25 212 = 30. 000 : 7 Thus it appears that a ratio having a uniform decreafe The ratio of _ nearly takes place; and we may therefore extend the table ae oP sof forces at both extremes, without the aid*of experiment, vapour is not as to a confiderable diflance. Thus affuming the ratios for each aia Sloat interval] of a 11°94 below 32° to be, 1.500, 1.515, 1.530, lefss 1.545, &c. and for each interval above 212° to be 1.235, £.220,, 1.205, 1.190, 1,175, 1.160, 1,145, 1.130, 8c. we can extend the table many intervals of temperature, and ‘determine all the intermediate degrees by interpolation. This method may be relied upon as a near approximation ; 3 3 however 2@4: FORCE OF YAPOUR. however it does not fuperfede the expediency of determi- nation by experiment ; though that is much more difficult above 212°, and below 32°, than in the intermediate de. grees; becaufe it is difficult to procure a fteady heat above 212°; and below 32° the variation of force becomes fo fmall as to elude minute difcrimination. It will appear from what follows that the extenfion of the table by this method above | 212° is in all probability accurate, or very nearly fo, for | 100° or more. | TABwLE Table of the Of the Force of Vapour from Water in every temperature force of aqueous from that of the congelation of Mercury, or 40° below zero vapour or fteam. 4 of Fahrenheit, to 325°. 4 ener Meine ett eer rere inches oF || eeeae Te nee ot Mercury. Mercury, Mercury. -40° 5013 || 25° 156 54° 9429 "-30 020 || 26 162||55 9443 =20 9030 || 27 ,168 || 56 9458 -10 9043 || 28 31741157 9474 a ——H|' 29 9180 ||58 5490 O 064] 30 ,186 ||59 ,507 1 066 || 31_ 5193 ||60 3524 2 ,068 || — — ||61 3342 3 30711) 32 2200 || 62 3960 4 3074 || 33 2207 |\63 2978 5 ,076 || 34 3214 164 597 6 3079 || 35 9221 ||65 "616 7 082113 9229 ||66 3633 8 3085 || 37 9237 ||67 9655 9 ,087 ||38 1245 ||68 676 10 3090 || 39 9254 ||69 3698 11 5093 || 40 5268 ||70 meee 12 ,096|| 41 3273 71 3745 13 4s) LOO WAR 5283 ||72 RO 14 104 43 3294 ||73 1796 15 3108 || 44 3305 ||74 BRB 16 31121 45 9316 1175 9851 17 116|| 46 5328 ||76 9880 18. 1201/47 3339 ||77 3910 19 ,124.|/ 48 351 ||78 3940 20 ,129 || 49 3365 ||79 971 21 _,134||/50 375 |/80 1. 00 22 9139 ||51 3388 |181 1. 04° 23 3144 1]52 3401 182 1. .07 24 1501/53 7415-83 1, 10 FORCE OF VAPOUR. Table continued. ‘Temper- _ Force of Vap- atures in inches of Mercury. 84° 1. 14 85 ae if) 86 Ube ee | 87 1. 24 88 1.228 89 12 90 Ts 136 91 1. 40 92 1. 44 93 1. 48 94 se 95 1. 96 1. 63 97 1. 68 98 1. 74 99 I. 80 100 1. 86 101 1, 92 102 1. 98 103 2. O4 104 2.631 105 2.208 106 2. OG 107 2.32 108 2. 39 109 2. 46 110 2. 703 111 2. 60 #2 2. 68 113 2. 76 114 2. 84 15 2. 92 116 3. 00 117 3. 08 118 S816 119 3.525 120 De toe 121 Os ae 122 3. 50 123 3.59 124, 3. 69 125 3. 79 126 3. 89 127 | 4. 00 Temper- atures 128° 129 130 131 132 133 134 135 136 137 138 139 140 el 142 143 14.4 145 146 147 148 149 150 ea 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169, 170 171 Force of Vap. in inches of Mercury. 4, 4. BS => . . tr Gr Gr or Gr Gr & BOB BOD « COOODOOMHHMDHTITIIIMWQDAAAODO Temper- Force of VaP. alas Mercury. PUL POO act)” POR aig 221173 13. 02 BA 174 13. 32 AT 1175 13. 62 60] 176 13. 92 73177 14, 22 86] 178 14, 52 00] 179 14, 83 14/180 15. 45 29/181 15. 50 44|| 182 15. 86 5911 183 16. 23 741) 184 16. 61 90/| 185 17. 00 05} 186 17-40 211] 187 17. 80 3711188 18. 20 531169 18. 6@Q 70} 190 19. 00 87} 191 19, 42 . 05 || 192 19. 86 2311193 20. 32 42]| 194 20. 77 6111 195 21, 22 8111196 21. 68 O1|| 197 22. 13 20|| 198 22. 69 40/1199 23. 16 60 || 200 23. 64 8111201 24, 12 02||202 24. 61 24.\|203 25. 10 46 || 204 25. 61 68 || 205 26. #13 91|}206 26, 66 15 || 207 27.20 41 1208 O7 sade 68 ||209 28, 29 9611210 28. 84 25211 29. Al 541212 30. 00 Se i ee pad 131213 30. 60 43 1214 31. 21 265 Table of the force of aqueous in inches of yapor or fteame 266 FORCE OF VAYOUR. Table of the forcbaf aquemin Table continued. vapor or fteam. “ely oh OTOL 4) ORS) BUR "268 BORN ame Temper- Force of VaP. || Tempers Force of Vap. | | Tempers Force of Vap--. ature. in inches of ature. in inches of acure. in inches of Mercury. Mercurys Mercury. 215° —— 31. 83|/252° 60. 05|| 289° ———- 98. 96 216 32. 461/253 61. 00}; 290 100. 12 pA) | 33. 09)|254 61, 92}/291 YOl. 28 218 336, %2\\256 62. 85|| 292 102. 45 219 34. 34\|256 63. 76|| 293 103. 63 220 34, 99}1257 64. 82]| 294 104. 80 221 35. 6311258 65. 78|| 295 105. 97 222 36. 25||259- 66. 75|| 296 107. 14 223 36. 88||260 676.7341) 29T 108. 31 224 57-5326 68. 72)|298 : 109. 48 225 38. 20]| 262 69. 72\| 299 110. 64 226 38. 89]|263 70. 731|3CO lll. 81 DDE 39. 59||264 71. 741/301 112. 98 298 40. 30]|265 HQ RGN B02 114.175 2929 Al. 02)|266 73. 771|\303 115. 32 230 41. 75||267 74. 79|\ 304 116. 50 231 42. 49||268 75. $0|\305 "117.68 232 : 43. 24)|269 76. §2||306 118. 86 233 44. 001/270 77. 85||307 120. 03 O34 44, 78\\271 . 78. 89)||308 J2t. 20 235 45. 58)||272 79. 941/309 1223 437 236 46. 39||273 80. 98]|310 123. 53 237 47, 20/|274 82. OL}\311 124. 69 238 48, 02)|275 So. ao | louie 125. 85 239 48, S4//276 84. 3511313 127. 00 240 49. 67||277 85. 47||314 [28 eRe 5 241 50. 50)\278 86. 5011315 129. 29 242 51. 34||279 87. 63}'316 130. 43 243 - 52, 18}1280 88. 75/317 13ib. 7 244 53. 03//281 89. 87||318 132, 72 945... 53. 88|/282 90. 99} 319 133. 86 246 54. 68|/283 92. 111}|320 135. 00 IAT 95. 541/284 93. 425 321 136. 14 248 56. ‘42/1285 94, 35]|/322 137, 28 249 57. 311/286 95. 481/323 138. 42 250 58, 21\|287 96. 64|| 324 139. -56 251 59, i 288 97. 80}|325 140, 70 Vapor from ‘On Vapour from Ether, &c. peck eat ag We conie now tothe confideration of vapour from other follow a general liquids. Some liquids are known to be more evaporable pe their = than water; as liquid ammonia, ether, fpirit of wine, &c. others lefs; as, quickfilver, fulphuric acid, liquid muriate of _ ‘lime, FROM WATER AND OTHER LIQUIDS, lime, folution of potath, &c. and it appears that the force of vapour from each in a vacuum is proportionate to its eva- porability. M. Betancourt maintains that the force of vapour from fpirit of wine is in a conftant ratio to that from water at all temperatures; namely, as 7 to 3 nearly. My firft experiments with fpirits of wine led me to adopt this con- clufion, and naturally fuggefted that the force of vapour from any other liquid would bear a conftantratio-to that of water. The principle, however, is not true, ejther with regard to fpirit of wine or any other liquid. Experiments made upon fix different liquids agree in eftablifhing this as a general law ; namely, that the variation of the force of vapour from all liquids is the fume for the fame variation of tempera- _ture, reckoning from vapour of any given force: thus afluming a force equal to thirty inches of mercury as the ftandard, it being the force of vapour from any liquid boiling in the open air, we find aqueous vapour lofes half its force by a diminution of 30° degrees of temperature; fo does the vapour of any other liquid lofe half its force by diminifhing its temperature thirty degrees below that in which it boils ; and the like for any other increment or decrement of heat. This being the cafe, it becomes unneceflary to give diftinét tables of the force of vapour from different liquids, as one and the fame table is fufficient for all. But it will be proper to relate the experiments on which this conclufion refts. Experiment on Sulphuric Ether. The ether I ufed boiled in the open air at 102 .—] filled a barometer tube with mercury, moiftened by agitation in ether. After a few minutes a portion« of ether rofe to the top of the mercurial column, and the height of the column became ftationary. When the whole had acquired the tem- _- perature of the air in the room, 62°, the mercury ftood at " 17.00 inches, the barometer at the fame time being 29.75. Hence the force of vapour from ether at 62 is equal to 12.75 inches of mercury, which accords with the force of aqueous vapour at 172°, temperatures which are 40° from the refpeétive boiling points of the liquids. By fubfequent obfervations I found the forces of the vapour from ether in all the different temperatures from 33° to 102° exaélly cor- sefponded with the forces of aqueous vapour of the like | range 267 The law enuns Clatcde Experiments with ether; in the barometer, below ebullition. 268 ON THE FORCE OF STEAM OR VAPOUR range, namely from 142° to 212°: the vapour from ether depreffes the mercury about fix inches in the temperature of 32°, above ebullition © Finding that ether below the point of ebullition agreed with water below the faid point, I naturally concluded that ether above the point would give the fame force of vapour as water above it; and in this I was not difappointed; for, upon trial it appeared that what I had inferred only from analogical reafoning refpe@ting the force of aqueous vapour above the boiling point, actually happened with that from ether above the faid point. And ether is a much better fubjeét for expe- riment in this cafe than water, becaufe it does not require fo high a temperature, with the fyphon I took a barometer tube of 45 inches in lect and having paremmc ters fealed it hermetically at one end, bent it into a fyphon thape, - making the legs parallel, the one that was clofe being nine inches long, and the other 36. ‘Then conveyed two or three. drops of ether to the end of the clofed leg, and filled the refit of the tube with mercury, except about 10 inches at the openend. This done, I immerfed the whole of the fhort leg containing the ether into a tall glafs containing hot water ; the ether thus expofed to a heat above the temperature at _ which it boils, produced a vapour more powerful than the at- mofphere, fo as to overcome its preflure and raife a column of mercury befides, of greater or lefs length according to the temperate of the water. When the water was at. 147° the vapour raifed a column of 35 inches of mercury, when the atmofpheric preflure was 29.75: fo that vapour - from ether of 147° is equivalent to a preffure of 64.75: inches of mercury ;“agreeing with the force’ of aqueous vapour of 257°, according to the preceding eftimation: in both cafes the temperatures are 45° above the refpeétive points of ebullition. In all the temperatures betwixt 102° and 147° the forces of ethereal vapour correfponded with thofe of aqueous vapour, as per table, betwixt 212° and 257°. I could not reafonably doubt of the equality con- Experiments in tinuing in higher temperatures; but the force increafes fo ae ag faft with phe increafe of heat, that one cannot extend the cluded air was experiments much farther without tubes of very iconve- ufed as the mea- nient lengths. Being defirous however to determine the fure of force, f oree — FROM VARIOUS LIQUIDS. force of the ethereal vapour experimentally up as high as 212°, I contrived to effeét it as follows:—Took a fyphon tube fuch as defcribed above, only not quite fo long, and filled it in the manner above mentioned, with ether and mercury, leaving about ten inches at the top of the tube vacant; then having graduated that part into equal portions of capacity, and dried it from ether, I drew out the end of the tube to acapillary bore, cooled it again fo as to fuffer the internal atmofpheric air to be of the proper denfity, and fud- denly fealed the tube hermetically, thus inclofing air of a known force in the graduated portion of the tube. Then, putting that part of the tube containing ether into boiling water, vapour was formed which forced the mercurial co- lemn upwards and condenfed the confined air, till at length an equilibrium took place. In this way I found 8.25 parts of atmofpheric air of the force 29.5 were condenfed into 2.00, at the fame time a perpendicular column of 16 inches of mercury in addition preffed upon the vapour. Now the force of elaftic fluids being inverfely as the fpace, we have 2.00 : 29.5:: 8.25: 121.67 inches = the force of the air within; to which adding 16 inches, we obtain 137. 67 = the whole force fuftained by the vapour, meafured in inches of mercury. The force of aqueous vapour, at the fame diftance beyond the boiling point, or 322°, is equal to 137.28, per table. Thus it appears that in every part of ale fcale on which experiments have been made, the fame law of force is obfervable with the vapour of ether as of water. Experiments on Spirit of Wine. By boiling a fmall portion of the fpirit I ufed (about one cubic inch) in a phial, the thermometer fiood at 179° at the commencement; but by continuing the ebullition it ac- quired a greater heat. The reafon is, the moft evaporable part of the fpirit flies off during the procefs of heating, and the reft being a weaker compound, requires a ftronger heat. The true point of ebullition, I believe, was nearly 175°.— The force of the vapour from this fpirit at the temperature of 212°, I found both by an open fyphon tube and one her- metically fealed with atmofpheric air upon the mercurial co- Jumn,; as with ether, to be equal to 58} inches of mercury. , This . 269 Force of vapor of ipirit of wines 270... ON THE FORCE OF STEAM OR VAPOUR This rather exceeds the force of aqueous vapour at dn equal diftance from the boiling point; but it is no more than may be - attributed to unavoidable little errors in fuch experiments. In Force of vapor of liquid am- monia, of muriate of lime. nh Na Forces of the vapour of mer- ¢ury and ful- phuric acid, a barometer tube the fpirituous vapour at 60°, over the mer- cury, depreffés the column about 1.4 or 1.5 inches; which is fomething lefs than the due proportion; one caufe of this may be the evaporability of fpirits, which in operating om fmall quantities, quickly diffipates part of their ftrength. Experiments on Liquid Ammonia. Liquid ammonia or volatile alkali, the fpecific gravity of which was .9474, boiled near 140°; in the barometer a fmall quantity depreffed the mercury 4.3 inches in the tem- perature of 60°. In higher temperatures it did not produce a proportional depreffion; becaufe the moft volatile part of the compound, expanding in the vacuum of the barometer, leaves the reft more watery, and confequently its vapour muft — be weaker ; efpecially when the portion ufed is confined to @ drop or two. Muriate of Lime. Put a portion of liquid muriate of lime over the column of mercury in a barometer. The boiling point of the muriate was found by experiment to be 230°. At 55° the deprefion was ,22 of an inch; at 65°—.30 — 70°2-.40 ‘ — 95°—.90 all which nearly agree with the forces of aqueous vapour 18% below the refpeétive temperatures. Mercury and Sulphuric Acid. Mercury boils by my thermometer at 660°, and fulphuric acid of the fpecific gravity 1.83, boils at 590°. It is very difficult to determine the precife force of vapour from thefe liquids in any temperature under 212° ; becaufe at {uch great difiance from the boiling point the vapour is fo weak as to be in effcét almoft imperceptible, Following the general law, the vapours of thefe fluids ought to be of the force .1, mer- cury at 460°. and fulphuric acid at 390°.—Col. Roi makes the expanfion of 30 inches mercury by 180, of heat = 5969 or 56513 and in a barometer the expanfion in’ the fame 4 FROM VARIOUS LItQuIDs, 271 fame circumftances is .5117; the differences are .0852 and .0534 which fhould meafure the effeGtive force of mercurial vapour of 212°, nearly, This is in all probability too much ; as it is next to impoffible to free any liquid en- tirely from air; and if any air enter the vacuum, it unites its force to that of the mercurial vapour. That the force of vapour from fulphuric acid, in low tem- peratures, is exceedingly fimall, will appear from the ens fuing feétion, SECTION Il. On Vapour in Air. The experiments under this head were made with manome- Effect of the ters, or ftraight tubes of different lengths, hermetically fealed sare t at one end, oF +s inch internal diameter, and their capacities The experi- divided into equal portions. A drop or two of the liquid, the eesti | fubjeét of experiment, was conveyed to the bottom or fealed ftoppea by ae end of the tube; the internal furface was then dried by a wire moveable plug and thread, and atmofpheric, (or any other air) was admitted cies into the tube, upon which a column of mercury was fufpended of gs of an inch, or of 30 inches, lefs or more, according to the nature of the experiment. By immerfing the end of the manometer, containing the air thus circumftanced, into a tall glafs veffel containing water of any temperature, the effect of the vapour in expanding the air could be perceived. It was firft indeed neceflary to determine the increafe air unaffeéted by any liquid (except mercury) would obtain by increafe of tem- perature: that was done, as will be particularly fhewn in the next eflay. * The expanfion of all elaftic fluids, it feems pro- bable, is alike or nearly fo, in like circumftances; 1000 parts of any elaftic fluid expands nearly in a uniiorm manner into 1370 or 1380 parts by 180° of heat. It will be unneceflary to repeat in detail the numerous ex- General law of periments made on the various liquids in all temperatures from go eae A 32° to 212°; asthe refults of all agree in one general rule or gether. The {pace at a principle, which is this: let 1 eatelak the ieee occupied by ee oni any kind of air of a given temperature and free from moifture 5 dire@ly as the ie i it, in inches of mercury ; f== the preflure and p= the given preffure upon it, in inch 95S Scapa i preffure lefs the Philofophical Journal, VoL. IIT, page 130, force of the force vapours 27 @N THE FORCE OF STEAM OR VAPOUR. force of vapour from any liquid in that temperature, in vacuo; then, the liquid being admitted to the air, an expanfion enfues, and the {pace occupied by the air becomes immediately, or ina fhort time = }] + ; or,, which is the fame thing, ere: eee poe Thus in water for inftance : Let p=30 inches, f=15 inches, to the given temp. 180°. Then, Btn NS for the fpace; or the air be« p—Sf - 30-19 comes of twice the bulk. If the temperature be 203°, f=25, and the {pace becomes fix times as large as at firft. ! If p=60 inches J =30 inches to the given temperature 212°; then the BOW i os 160-3 inches of mercury, and at the temperature of 212°, produces vapour which juft doubles the volume of air. If ether be the inftance: let the temperature be equal 70°; then f=15 ; and fuppofe p30; in this cafe the colume of air is doubled; that is, ether of 70° being admitted to any por- tion of air, doubles its bulk. The expanfion of hydrogenous gas and atmofpheric air by the vapour of water is the fame for every temperature. * Sulphuric acid does not expand atmofpheric air to any fen- fible amount by the heat of boiling water. The theory of thefe faéts is evident upon the principles laid down in the former eflay: for inftance; let it be required to explain the experiment with water of 212° under a preffure of 60 inches. Here the air was condenfed into the fpace 1 by the preffure of 60 inches; but being expofed to water of 212°, a vapour arofe from it equal in force to 30 inches ; the air theres fore expanded till its force alfo became = to 30 inches, which was effeéted by doubling its volume: then the vapour prefling with 30 inches force and the air alfo with 30 inches force, the two together fupport. the preffure of 60 inches and the equi+ librium continues. In fort, in all cafes the vapour arifes toa certain fpace = 2;, or water under the preffure of 60 PORTABLE FURNACEs 973 ,certain force, according to temperature, and the ait adjufts the equilibrium, by expanding or contraéting as may be required. The notion of a chemical affinity fubfifting between the gafes Thefe faéts do and vapours of different kinds, cannot at all be reconciled to = aoe thefe phenomena. To fuppofe that all the different gafes have chemical affinity the fame affinity for water might indeed be admitted if we bene eaiand could not explain the phenomena without it; but to go further, ici and fuppofe that water combines with every gas to the fame amount as its vapour in vacuo; or in other words, that the elafticity of the compound fhould be exaétly the fame as if the two were feparate, is certainly going far to ferve an hypothefis. Befides, we muft on this ground fuppofe that all the gafes have the fame force of affinity for any given vapour; a fuppo- fition that cannot be admitted as having any analogy to other eftablithed laws of chemical affinity. (To be continued, ) (SS Sr ES RE SE TT RTM T| XIV. Defeription of the Portable Furnace conftrufled by Dr. Blacl:, and fince improved, In a Letter from’ Mr. Accum, To Mr. NICHOLSON. Dear Sir, In my Syftem of Practical Chemiftry, Vol. IT. p. 357, I Defcription of have given a Defcription and Drawing of a Portable Uni- whale in verfal Furnace, which in the praétice of my profeffion I operations. found the beft furnace for all chemical operations whatever which require like aid. The number of furnaces which I have caufed to be made for different philofophers of that kind, and the ufeful hints which I have received from diffe- rent quarters, have materially improved it, that I flatter myfelf, whether a defcription of this furnace would not be. acceptable to your readers, particularly to thofe who have no accefs to the laboratory of the operative chemift ; for thofe who are familiar with practical chemiftry will readily allow, that a furnace capable of producing a very low and very intenfe heat is one of the moft requifite and moft indif- penfible inftruments of all the apparatus of chemiftry. The Vor. VI. DecemBer, 1803. X iin great 7 4: PORTABLE FURNACE< Defcription of great advantage of this furnace (which was fir/t invented bi ce poe DP Black, and improved by others) above all others Tam ac~- nace in chemical operations. quainted with, confifts in confuming as little fuel as poffible, in producing quickly, if required, a very intenfe heat—in regulating expeditioufly, and at pleafure, its intenfity—in duel fut it as direétly, and as fully as poflible, to the fub- {tances upon which it is intended to aét—and moreover in enabling the operator to perform his operations in the clofet, or in any other place, without the rifk of endangering the conflagration of the furrounding objeéts, which were not meant to be expofed to the action of heat. atcoill — ie h | =U Sh, ny ea — 7 = hii = | |e == <= = = = === es as a ' 2 ; / 7, 4 ; 4 ’ ; > ag ’ Phdlos. Journal Vol.V1. PLVL p44. | Aurwnace fer Ovapora lion ty veg wlater Sempre 2alhire: dahon. fru viallel Nath Pore AB { QW \’"blbl»h SGWQ.WHu00wwW”Bbu'’#sE’.F”F”ivn MGS \ XW ll Ro AN Sante ee Zt WN Lee un the tine ©, G SS SS \\ | \ es Metres of 39 4 Inches. q 2 3 4 o Vution Se. Rugxell @! * ~ . ih « yi s > . “1 < . ’ - ee ~ ‘- ! { - k yt TNE Tit iis TM Ts TTT oo Sry =F =n Prilos. Jranal Vou.Vl Pl. Vip.144. k i ume ul HE j (ii | | | | HIE i I WE il l iii il ml i | ) il Wi. . Piulos. Journal Vou.Vl. Pu ViLp.144. Se es a rma NTR NE NATIT TU ah Hite aN aa i ay { Ni \ AN) M ok ng: , ANP QMNAD « A Fm Hua CYL AI AAINEC CVVLE’ é MW ——— aS O7 Oaths Philos. Journal Vol.VE PLIXp.224. ¢ Gombe (FU I ys method o sf fio? 2 e roy acro#wld “ic 4 O bere a/b “a OI. Drawn by Blunt Engraved byMutlow Rupiell @? . Pralos. Jounal Vol VI. PUX. p. 224. Ap aalis fo by ee be iy and: fer See Drawn by Biot. Engraved hy Mutlow Rupsell Oo: t i> Os Philos. Journal VOLVIFUAL p.22 4. || iF Ha ro a a, © i {|| \ Sa | | at : * Engraved by Mutlow Rujiell Gl \ Philos. Journal Vol.VI-Pt.XILp. 224. ippenny yg Wy, a nfo, oe Yeoupg hj « 2g YY iy bury ffar tof, PUIUMNMYED ‘ O ee E r ~ eo — ee eee ee a _- ee a = as Ol Se Sr. eS OS So Philos. Journal Vol. VL. PUXM. p. 304. ae a | Drawn by Blunt. be a Ae roan Philos Journal Vol, VI. PUM. p.304. - pees aC. reguléting ee, Ay | £ GUA MAgubis 0 ff } rl " ay | | \ 4 + ¢ 7 4 Mla sooo ees WWF — 1 le Uf "V"YY it H hil z i UY ntl — Tz YW, fs S:> ‘il CO yy, ae LLU LZ Z| ll“ INDE X. A, Accum, Mr. on the combinations of fulphur and phofphorus, 1-—Analyfis of the Egyptian heliotropium, 65— Defcription of an apparatus for drying chemical produéts and for congelation, 212——LetterrefpectingAuguftine earth, 214—Defcription of an improved por- table univerfal furnace, 273 Acetite of lead, remarks on, 223—Two fpecies of, ib. Acid, benzoic, found in ambergris, 182 ——, gallic, cannot be obtained pure from bark, 34 ——, nitrous, decompo(ition of, by phof- phuret of fulphur, 5 we——, phofphoric, is cryftallizable by long keeping, 131 . ——, prufiic, new procefs for obtaining it pure, 134 ; -—, fulphuretted-muriatic, pPoduétion of, 104——Properties of it, ib.—-Che- mical examination of, to5—Compofi- tion of, 107—Remarks on, 108 ~=——-, fulphuric, component parts of, 93 —Seems to be produced whenever ful- phur is acidified or fublimed, 97, 98 =-——, fulphurous, properties of, 93— Contains fulphuric acid, 94—-Analyfis of, 95—Is probably a compound of ful- phuric acid and fulphur, 97 Vor. VI. / a Adams, 235 , Adipocire obtained from ambergris, 136 Acroftatic machines, advantages to be derived from the ufe of, 194—-Experl- ments with,195— Apparatus for making terreftrial obfervations from,196—Con- ditions neceffary to obtain correct re- fults; 199—~Valuable properties of, ib. Auguftine earth, queries refpecting, 139 —Method of extraéting, 214—Cha- ratters of, 215 Aikin, 130 Air is decompofed by phofphuret of ful- phur, 4—Its moiiture does not impede telefcopic vifion, 10—Dry, is unfa- vourable to ftellar obfervations, 13 — -pump, letter from Dr. Prince re- fpeCting hiss 235—Improvements in, 236—Is the fimpleft form now ufed, 238 Alloys, experiments on the comparative wear of feveral, 145—Compound, are real chemical combinations, 160 Ambergris, a product of impaired digef- tion, 179——Natural hiftory of, ib»—Ex- ternal qualities of, 130—-Formerly claf- fed among bitumens, ib.—Geoftroy’s analyfis of, ibh—-Many varieties in commerce, 181—Fabrication by art, ib.—New refearches into the nature of, ib.—Phyfical properties of, ib.—-Che- mical properties of, 1$2—-Alcohol iz the INDEX. the only re-agent to be depended on, ¥84—Examination of the produéts ob- tained from, 185—Recapitulation, 186 =—~Conftituent parts of, 137 Apparatus for drying precipitates and for congelation, 212 Eudiometric, contrived and ufed by Dr. Hope, 210 for meafuring the aliquot parts of an inch, 247 — for meafuring the foree and re- gulating the emiffion of team, 249 ——-——— for raifing water by atmofpheric preffure, 217 Aqueous humour of the eye, chemical ex- amination of, 22 “Arachis hypogza cultivated for economi- ’ “eal purpofes, 224 Arfeniated hidrogen gas, chemical analyfis: and properties of, 200 Aurora Borealis does not affeé& telefcopic vifion, 33 B. “Barks, aftringent, chemieal examination of, 31—Properties of the refidual por- tions of, 36 Barytes not to be depended on in the ana- lyfis of fulphites, 94 Baumé, 131 Baunach’s obfervations of St. John’s wort, 286 Bawens, 253 Bayen, 182 Bergman, 74 Beril, Saxon, component parts of, 215 Berthollet on a method of giving the ap- “pearance of cotton to hemp or flax, 252 Bertholon, 138 Bertrandi, 22 Betancourt, 260, 267 Biggin, 34 Biot, 135 Bifmuth, difference between hot and cold folutions of, 63 Black, Dr. his theory of heat, 25—His portable furnace, 273 Blagden, Sir Charles, 281 Body and mind, philofophical opinions re- {pecting, 161 Bones, foffil, found in America, 247 Bonnet, 173 Boftock, Dr. on the efflorefcences found on walls, 109 Bournon, Count de, 187 Brandy, method of giving its flavour to malt fpirits, 140 Briffon, 158 Buckholtz, 63 Bucknall, 124 Buffon, 216 Buildings, their vicinity impedes telefco- pic vifion, 14 Cc. Calamines, opinions of authors refpeéting, 74—Analyfis of that of Bleyberg, ib. External charatters, ib.~-Component parts of, 76.—Analyfis of the Somer- fetfhire, ib.—External charafters, 77. Component parts of, ib.—Analyfis ef the Derbyfhire, ib.—External charac- ters of, ib.—Component parts of, 78, —Analyfis of the ele&tric, of Regba- nia, ib,—-Component parts of, 79— General obfervations, 80--Chemical theory of the compofition of, 32—Has mot been yet difcovered as an uncom- bined calx of zinc, 85 Calorimeter, its ufe as an inftrument de- fective, 29 Camelford, Lord, 2 Candles, on the light emitted by different fizes of, go—Rules for computing the proportion of, 9% Carbonate: INDEX. Carbonate of magnefia, native, examina. tion of, 240—Difference between it and the artificial, 241 — of foda found efflorefcent on walls, 111—Method of obtaining pure, 193 Cardan’s padlock, 45 Carlifle, Mr. on a method of clofing | wide-mouthed veffels, 68 Caft iron, effeéts produced on it by long immerfion in the fea, 70 Cataract of the eye, conjectures relative to the caufe of, 25 Catechu, the moft powerful of all the tan- ning materials, 40o—Comparative value of, 41 Cement for extreme branch grafting, 28 Charcoal carinot be abfolutely feparated from phofphorus, 133 Chenevix, on the chemical nature of the humours of the eye, 21, 93, 203 Chimnies, defcription of a machine for cleanfing, 255 . Chrouet, 22 Cinchona, on the febrifuge principle of, 136—Obfervations on the varieties found in the fhops, 137—Comparifon between its medicinal virtues and thofe of gelatine, 138—-Does not contain ge- Jatine, 225—-Experiments and obferva- tions on, 226—Contains a new prin- ciple analogous to gelatine, 228 Cinchonin, the new principle of cinchona, experiments to prove the exiftence of, 226—Comparifon of its properties with thofe of gelatine, 228 Clays, Cit. 252 Clouds, effeéts produced by them on te- le{copic vifion, 15 Coin, obfervations on its lofs of weight by wear, 147-——Difadvantage of foftnefs in, 148—Lofes but little in ordinary circu- jation, 150—-Comparifon of the value of different alloys for, 1§2—Erroneous opinion refpeéting that of the prefent reign, 164 Cold, the focal length of mirrors is alter~ ed by, 16—-Experimental proofs of this effe, 18 Colours obtained from St. John’s wort, 286 Congelation, apparatus for promoting, 213 Conté, 142 Corer, 72 Crawford, Dr. 26 Crocodile, effects produced on atmofphe- ric air by the refpiration of, 246 Crofthwaite, 118 . Cryftalline humour of the eye, chemical examination of, 2g—Is very fubjeét to diforders, 25 | Curandau on the imperfeétions of evapo~ rating furnaces, with a new method of conftructing, 114 Cuthbertfon, 245 D. Dalton, Mr. on a miftake in Kirwan’s eflay on vapour, 118—-On mixed gafes ; on the furce of fteam ; on. evaporation, and on the expanfion of gafes by heat, 257 Davy, Profeffor, on: he conftituent parts of aftringent vegetables, and their ope- ration in tanning, 3% De Dominis, 56 Delufions, audible, occafioned by debility of the organs of hearing, 231 Derangements of the animal fyfem, dif- quifitions on, 229 Defcartes, 56 Divacus, 73 Donkin’s table of the radii of wheels, 86 Dree, Marquis de, 188 Dry-rot, method of fecuring timbers in- jured by, 120 Dubree, 130 ba Duncan, ees INDEX, Duneay, Dr. on cinchona, 225—-On gum-kino, 234 S E. Earthquakes, their effeéts in South Ame- rica, 242 Edelcrantz, Sir A. N. his method of rai- fing water for the purpofes of refrigera- tion, 41- Edwards, Mr. an erroneous affertion of his refpecting the eye-ftop of refleting telefcopes, 248 Efflorefcences on walls, experiments and ‘-obfervations on, 109—Enquiries into the origin of, 112. EleGtricity of the oppofite poles of the galvanic pile, experiments on its nature ahd effets, 222 Englefield, Sir H. C. his account of two halos with parhelia, 54 Eudiometric apparatus conftruéted and ufed by Dr. Hope, 6% properties of phofphuret of _fulphur, 4 Evaporating furnaces, on the conftruétion of, 114, Evaporation of liquids, experimental eflays on, 257 Excrements of mammiferous animals, are analogous. to’ ambergris and mufk, 180 Extractive matter of vegetables, is moft abundant in the middle bark, 35—Is abforbed during the procefs of tanning, 39——Is probably the canfe of foftnefs in fkins, 40—Mutual a¢tion with tan- nin, ibe Extreme branch grafting, a method of re- ‘ftoring: decayed. trees, 124—-General preparation and management, 126— Teftimonials of its fuccefs, 128 Eye, its funétions are fubjeét to the laws of optics, zI—-The chemical hiftory of its humours limited, 22—-Experiments on the humours of, in different ani- mals, ib. Eye-ftop of. refleGting telefcopes, cor- reCtion of an error refpeéting the, 247 F. Fairman, Mr. on the reftoraticn of des cayed trees by a new method of graft- ing, 124 Fafcolomes, a new fpecies of quadrupeds, defcription of, 141 Febrifuge principle of cinchona, memoir ons 146 ‘ Feeding of leather philofophically account-_ ed for, 40 Fermentation, enquiries into the nature and caufes of, 221 Pichtegurys Flax, method of giving the appearance of cotton to, 252 Fluidity may confit in the change of the capacity of bodies for caloric, 28 Fogs do not impede telefcopic vifion, 10 Foffil banes, large ones found in both Americas, 247 Fourcroy, 22, 24, 94, 186—A miftake . of his rectified, 133 Froft, its ,effe&ts on telefcopic vifion, i2 ; Fruit-trees, new method of reftoring de- cayed, 124 . Fuel, wafte of its confumption in fur- naces, 114. Funcke, 63 P Furnaces, evaporating, on the conftruc- tion of, 114——-Caufe of the defective aétion of, 115—-General remarks, 117 —Defcription of a new, ib, » portable, improvement in Dr. Black’s, 273 _ : Gaji- INDEX. Gs Gai-Luffac, 253 Galvanic phenomena, additional experi- ments on, 221 Garden, 2 Gafes, cannot be reduced to a ftate of liquidity, 259—Differ from {team or vapour in their mechanical aétion, ib. Have no chemical affinity with va- pour, 273 -——, arfeniated hidrogen, difcovered by Scheele, 200—Properties of, ibs-New inveftigations,; 201—Methods of ob- taining, \ ib.—Phyfical properties of, 222—Action with gafes, ib.—Theory of its decompofition by oxigenated mu~ riatic acid gas, 204—Tefts to difcover its prefence, 205, 208—Compofition of, 206—Habitudes to acids, ibh——-Cu- rious phenomenon, 207—Habitudes to metallic folutions, 208—-To various other bodies, 209 “———, mixed, experimental eflays on the conftitution of, 257—Do not repel each other, 258—Are all equally expanded by heat, ib. =—, fulphurous acid, abforption of by water, 93 Gelatine, propofed as a fubftitute for cin- chona, 138—Comparifon of the medi- cinal virtues of the two fubftances, ib. —Is not the febrifuge principle, 225 —Comparifon with cinchonin, 229 Geoffroy, 141, 180 : Gefner, 72 Glauber, 216 Goetling, 214 Gold, experiments on the comparative wear of various alloys of, 145—-Stamp- ing increafes the lofs, 146—Fine lofes more than alloys, 147—Conclufions, ib.—=Diftinétion between hard and brit- tle, 149—Further experiments, 150— General refults, 152—-Beft adapted for 5 coin when alloyed, 153-~Comparifon of three kinds of ftandard, 155-—Spe- cific gravity of, alloyed with different metals, 157 Grafting, extreme branch, propofed as 2 remedy for decayed trees, 124 Gram, 71 Granet, 131 Gregor, 113 Greville, the Right Hon. Charles, on meteoric ftones and native iron, 187 Ground-nut. of the Weft Indies, culti- vated for its oil, 224 Gruber, 47 Gum-kino, an erroneous appellation, 232 Gunpowder, antiquity of the invention of, i Guyton’s pyrometer of platina, 89—-Ex- amination of a native carbonate of mag nefia, 240 H. Halos, account of two remarkable ones with parhelia, 54-—-Theory of, 56 Hanway, 255 Haffenfratz’s firft memoir on coloured fhadows, 282 Hatchett’s, Mr, experiments and obferva- tions on gold and its different alloys, 145 Hauy, 74 Hazinefs, effets produced by it on tele- {copic vifion, 15 Heat, the focal length of mirrors altered by, 16—-Experimental proofs of this effe&t, 18—Theories of, 26—Thé thermometrical degrees of, are to be taken according to the capacity of the body, 27—Applied during a change of capacity does not alter the temperature, ib.——The experiments to afcertain the natural zero erroneous, 28—Method of afcer- INDEX. afcertaining the capacity of bodies for, 29—Specific, is proportional to capa- city for, 30—Theory of its aétion on fulphite of potafh, 96—Extraordinary infenfibility toy 139 Hebden, 255 Heliotropium, Egyptian » phyfical proper- ties of, 65—Analyfis of, 66-—Compo- nent parts of, 68 Hemp, method of giving the appearance of cotton to, 253 Herfchell, Dr. on the transit of Mercury over the Sun’s difk, and on the defec- tive action of mirrors, 8 Hidrogen, poffibility of its combination with metallic fubftances, 204 Hoar-froft does not impede telefcopic vi- fion, 13 Home’s, Mr. obfervations 9n the ftruc- ture of the tongue, 276 Mope’s, Dr. eudiometric apparatus, 61, 210 Horizon, its Feb, dip is influenced by the flate of the atmofphere, 51—Caufe of the errors:in nautical obfervations on the, 52—Remedy, ib.—-Method of correcting the errors of the glaffes, 53 Hornblower, Mr. on meafuring parts of an inch, 247—On the eye-ftop of re- flecting telefcopes, ib. Howard, Mr. 187—Apparatus for raifing water by atmofpheric preffure, 216 Huddart, 57 Hufeland, 164 Humours of the eye, experiments on the chemical nature of, 22 Hutton, 260 Huygens, 56 Hydrate of zinc, 81 I. Ice, phenomena of its abforption of heat during liquefaction, 26 { Imagination, the difeafes of, require in- veftigation, 163 Infenfibility to- heat and chemical agents faid to be poffeffed by a Spaniard, 139 Tron, prefervation of, from ruft, 142 ——, caft, effects of long immerfion in the fea on, 70 ——, native, its origin analogous with that of meteoric ftones, 188 Irvine, Dr. his method of afcertaining the capacities of bodies for caloric, 29—In= tended publication of his works, 31 > Mr. his letter in vindication of his father’s theory of heat, 25 Jars, on the method of clofing wide- mouthed, 69 Jehangire, emperor, his; narrative of a metallic ftone that fell in India, 189 Juch, 132 K, Kant’s tranfcendental idealifm, foundation of, 177 Kino, is not a gum, 232—Natural hif- tory of, ib.—Medicinal ufes of, ib. Chemical examination of, ib.—Is a fpecies ef tannin, 234—Reference to Dr. Duncan’s account of, ib. Kirkpatrick, Col. 188 Kirwan, Mr. 26—A miftake in his effiiy on vapour rettified, 118 laproth’s analyfis of natrolite, 19% Krueger, 173 L. Lac fulphuris, compofition of, 102 La Grange’s analyfis of ambergris, 179 Lampadius, 62 Language of the South gery day 0% copi- eutnefs of, 246 La INDEX. La Place’s memoir on the tides, 239 Lavoifier, 29, 93 Laws, general, their eftablithment of high value to fcience, 257 Lead, acetite of, remarks on, 223—T wo {pecies of, ib. Ve'Cat; 21 Light, on the quantity of, emitted by candles of different &zes, go—Rules for computing, 91 Lights, northern, do not feem to impede telefcopic vifion, 13 Lime, probably hurtful in tanning, 41 Litharge is foluble in acetons acid, 130 Lomet oh the employment of aecroftatic machines, 194 ‘Ludlam, 53 Lute for chemical operations, preparation of, 140 M. Machine for cleanfing chimnies, 255 Magnefia, examination of a native carbo- nate of, 240—Difference between it _ and artificial, 241 Magnifiers, high, are not calculated for folar obfervations, 8—Cannot be ufed while the temperature of the mirror is fufceptible of alteration, 20 Malt fpirits, method of giving the flavour of brandy to, 140 Manufcripts, Indian, of the fifteenth can- tury, 245 Margraff, 1 Maton, 37 Mechanifm for equalizing the motion of a fteam engine, 218 Mendeljohn, 173 Menftrua, thofe made ufe of in tanning probably injurious, 41 Merat Guillot, 33 _ Mercury, obfervations on its tranfit over the Sun’s difk, 8—Has no apparent at- _mofphere, g—Is truly fpherica!, ib. Metals are combuftible in non-refpirable gafes, by galvanifm, 62—May be com-~ bined with hidrogen, 204 Meteor, account of an extraordinary one feen in France, 135—-Account of the fiery one of November laft, 279 Meteoric ftones, fall of, 135—Experi- ments and obfervations on, 387 Mind and body, philofophical opinions re- fpecting, 161 Mirrors, on the caufes which prevent their fhewing objects diftin@tly, 1o—Their focal length affected by changes of tem- perature, 16—Experiments to afcertain this faét, 18—The figure of the re- fiecting furface is injured during this change, 20—A remedy fuggefted, Zs Moifture of the air does not impede telé. {copic vifion, 10 Molar, 253 Monge’s theory of horizontal refra@tion objeéted to, 47, 51 Mont Perdu, journey to the fummit of, 250 Moritz, 173 Mofer, ib. Mountains of South America, curious particulars refpecting, 242 Muriate of potafh, produétion of, 99 Muffin Pufchkin, 132 Myrobalans, chemical examination of, 37 Nairne, 235 Native iron, 188 Natrolite, natural hiftory of, 191—Phy- fical properties of. ib.—Analyfis of, ibh—Component parts of, 193—The name derived from the foda it contains, 194 Newton, 56 Nicolai INDEX. Nieslai on the fpeétres produced by dif- cafe, 161—Difquifitions on his account, 229 Nitrate of filver, a good téft for arfeni- ated hidrogen, 208 Go. Oétant, advantageous method of conftruct- ing, 220 Ocular fpeétra, nature and caufes of, 229 Oil, from the arachis hypogea, or ground nut, 224 of rofes, cryftallization of, 134 Orchards, obfervations on the ufelefs trees in, 124 -Orfted, 22x Oxide of fulphur, inquiries into the na ture of, 102 —— of titanium, reduétion of, 62 ——, white, of phofphorus, properties of, 133 Pe Padlock of fecurity, 43—Method of ap- plying as a defence to the key-hole of a door, 44 Paramos of South America are piercing cold, and deftitute of vegetation, 242 Parhelia, theory of, 56 Payffe on the preparation of a lute for chemical operations, 140 Pearl-afh, probably hurtful in tanning, 41 Pelletier, 15 79, 130 Pepys, Mr. the inventor of the apparatus for drying precipitates, 287 Phantoms produced by difeafe, 16x Phofphate of foda, new method of pre- pating, 63 Phofphoric acid, cryftallization of, 131 Phofphorus, experiments and obfervation» on its combination with fulphur, 1— Danger of expofing the compound to heats 2—Phenomena produéed by the diftillation of the mixture, 3-—Cannot be obtained pure, 133—Converfion in- to white oxide, ik. 5 liquid, produced by diffolv- ing phofphuret of fulphur in oil, 5—~ Luminous properties of, 6 Phofphuret of fulphur decompofes water and atmofpheric air; 4—May be em- ployed as an eudiometer, ib.—«Decom- pofes nitric acid, g5—Is foluble in fat oils, ib.—In ether and volatile oils, and fparingly in alcohol, 6—Accenfion by oxigenized muriatic acid gas, ibbh——When inflamed it burns in nitrous gas and ni« trous oxide, 7—Combuftion in a va- cuum, ib.—-No change of temperature produced by its formation, ib.<—More poifonous than phofphorus, ib. — Pinel, 140 Poole, 37 Preponderance, apparatus for illuftrating the doétrine of, 59 Prince, Dr. letter from, refpecting his air-pump, 235 Produéts of chemical analyfis, apparatus for drying, 212 Prouft, 36, 132, 201 Pruffic acid, method of obtaining it pure, aa Pfycological remarks on the fpe€tres pro- duced by difeafe, 161 Purification of phofphorus, impoffibility of, 132 Purkis, 41 Pyrometer of platina, 89 Q. Quadrant, refle€ting, improvement on, 219 Quadrupeds, news 141 Ramond's INDEX. R. Ramond’s journey to the fummit of Mont Perdu, 250 Refraétion, horizontal, obfervations on the quantity of, 46—lIs not the fame as reflection, 48-—Attributed to variations in the temperature, 49—-Table of ob- fervations, 51 Regnier’s padlock of fecurity, 43—Re- marks and annotations on, 45 Refin from ambergris, properties of, 186 Reverie, a {tate favourable to the pro- duGtion of fpectres, 229—Inftances, Oa ar Richter, 135 Ritter’s experiments on galvanic pheno- % _™mena, 221 Roi, Col. 270 Rothe, 73 Rutter, 100 NI Sabres made of native iron, 190 Schaub, 134 : Scheele difcovered arfeniated hidrogen gas, 200 Sciences, antiquity of, in South America, 246 Screw, meafuring, 247 Seguin on the febrifuge principle of cin- chona, 136—Abftraét of his enquiries concerning fermentation, 221 Sextant, its ufe in aeroftatic obfervations liable to error, 196—Additional appa~ ratus to remedy the defect, 197—~Suc- cefsful refults, 198 Shadows, coloured, memoir on, 282—— ~ Phenomena of, ib.—Obfervations on their nature as produced by various caufes, 283—General refult, 285 $mithfon’s, Mr. analyfis of fome cala- amines, 74 Vox, VI. Soda, carbonate of, found eflorefcent on walls, rr1—Method of obtaining pure, AQS'Sn Fy South ‘America, curious particulars re- {pecting, 242 Spaniard, faid to be infenfible to the ac- tion of heat or powerful acids, 139 Specific gravity of gold fingularly affected by alloy, 157—Various circumftances which affe&t, 158—Caufes of the va- riation enumerated, 159—Table of, 160 . Spectres, memoir. on thofe produced by difeafe, 161—Attempt to explain them by natural caufes, 229 Speculum of a refie&ting telefcope is af- feéted by change of temperature, 16 Spinoza, 172 Square, reticulated, method of conftruc- ting, 247 Stars, caufes which affect their apparent magnitude, 14, 15 Steam, its force the fame from all liquids under the fame conditions, 258, 267, 271—Is capable of becoming liquid, 259 —Its mechanical aétion different from that of gafes, ib.—-Method of meafuring the force of, 260—Examination of the progreffion of its force; 262—Tuble of its force at every degree of temperature, 264—General law of its expanfion in -air, 271——Has no chemical affinity with gales, 273 engine, method of equalizing the motion of, 218 valve, felf aéting and regulating, 249 Steinacher, on pharmaceutical preparations, "130 Stones, meteoric, 135—Their exiftence fully eftablifhed, 1837—Hiftory of three new fpecimens, 188 St. Amand, 188 St. John’s wort, chemical examination of, 286 ¢ Su'phur INDEX. Sulphate of magnefia found éeflorefcent on walls, 109 of potafh, compofition of, 100 of foda, prepared from gypfum, 64—Found efflorefcent on walls in two ftates, 110 of ziné, component parts of, 80 Sulphites, analyfis of, 94—Experiments on the aétion of acids with, 98 -——— of lead, component parts of, a of potafh, component parts of, 95 —Changes vroduced on, by heat, ib. Sulphur, expetiments and obfervations on its combination with phofohorus, 1— Danger of expofing the compound to heat, 2—Phenomena of the diftillation of, 3—-May be combined with three dofes of oxigen, 92—External charac- ters of, 103=*Oxigenation by compound agents, 103 Sulphuretted muriatic acid, produ€tion of, 104—Properties of, ih—Chemical ex- amination of, 1o5—-Compofition of, 107—Remarks on, jos Sulphuric acid, component parts of, 93— S¢ems to be formed whenever fulphur 18 acidified or {ublimed, 97, 98 Sulphuroys acid, properties of, 93—Con- tains fuiphuric acid, 94—Analyfis of, 9§—-Is probably a compound of fulphu- ti¢ acid and fulphur, 97° Sumach, chemi¢al examination of, 36 Super-fulphate of potafh, produétion of, 99—Component parts of, 101 Swedenborg’s vifions philofophically ac- counted fory 171 > Swediaur, 179 Syphon, improvement in, 218 Syftem, animal, difquifitions on the de- rangement of; *229 | i Tannin, method of obtaining it pure, 33 e=Is moft abundant in the interior whité bark, 35—Relative quantities in diffe rent barks, ibs—-Various fub(tances in which it exifts, 37—Its fpecific agency always the fame, 38—Affinities and habitudes of, ibh—Mautual aétion with extractive matter, 40 Tanning of fkins, experiments ony 33—+ Difference between the flow and quick procefles, 33, 40—Extraétive matter is abforbed during the operation, 39—Its perfection not to be judged of by the increafe of weight, 4o0—Vegetables which are of mott value in, ib. Teas, chemical examination of, 37 Telefcopes, reflecting, caufes of the dif- appointments in the ufe of, 10 Temperature of bodies, muft be eftimated according to their capacities for caloric,27 Tennhart, 172 Thenard, 93—Remarks on the acetite of lead, 223 Thompfon, Dr. on the compounds of fale phur and oxigen, 92 ‘Thought, fpeculations on its nature delu+ five, 162 Tides, memoir on the, 239 Timbers of houfes, method of fecuring decayed, 120 Titanium, reduétion of its oxide, 62—4 Properties of, 63 Tongue, obfervgtions on the ftructure of, 276—Cafes in which a portion was fe- parated without affecting the nervous fyftem, 277 : Trees, decayed, method of reftoring, 124 —Teftimonials of its fuccefs, 428 Tremler, 71 Tromfdorff, 62—Chemical analyfis of ar- feniated hidrogen gas, 200 Tungften, is not acidifiable, 134—Me- thod of obtaining, 135 | v. Unguentom nttritum, on the compofition of, 139 ; Vana INDEX. Vv, an Marum, 7 Vapour, ftate of, in the atmofphere, 118 —Experiments on that produced from ether, 266—From fpirit of wine, 269 _ From liquid ammonia ; from muriate of lime; and from mercury and fulphu- ric acid, 270—See alfo Steam Varnifh, a fine red, 287 Vauquelin,~ 94, 101—Experiments on gum kino, 232 Vavaffeur, Le, 70 Vegetables, aftringent, experiments on, 31%—-Properties which render them va- luable in tanning, 40 Venturi, 59 Veflels, method of ftopping wide-mouthed, 68, 216 Vifion, telefcopicy caufes which affeét it, zo-~Can only be diftinét in moift air and uniform temperatures, 36 Vitreous humour of the eye, chemical examination of, 23 Volcanos, curious particulars refpecting thofe of South America, 242 Yon Hombolt, on the natural hiftory of ' South America, and the language and icience of the natives, 242 Ww. Walker, Mr. on the proportion of light from candles of different dimenfions, go—Improvement in his reflecting quadrant, 219 Walls, experiments and obfervations on the efflorefcences on, 109—Enquiries into the origin of, 112 Water, decompofition of, by phofphuret of fulphur, 4—TIts fpecific caloric is greater than that of ice, 26—Method of raifing, for the purpofe of refrigera~ tion, 41—Velocity with which it Aows through a vertical pipe, 6¢—a. + Ly reree "reget rte D-O 4 6+ 789 0d-@ R08 Lites Peeed eee ert esele ils° STitpratp iene ls ee et fer peceettsee oss 5 Fete een ol cena Str yittorstpeseets Ee Sot eee tse ete Paed Bes SS peres seas Tot stere ee Societ tres see Sree se tt? +t? $338 Bi SySonatocsses ples ett tae en Septet ey peseaieees Saaeqeeeet es tee aheee ereees reg bY af] jag Trott trozneeeeis +35 Sasiae SHE EESS sees eperenee Oe tt bla =a ; sr ph ae am ty is tere Hl niiigerse Hh: Steer HEH EEE SHE oe Siaiees +L Eisgesstesiocsses Prepestisseetissteseess SSSi3S2 ES eierecsestetsestrssertes fotterer ite 4333 pith 3 e. aa23 pexeres eae sse eat ave Sa oer Ssewce etede: Heerlen es thet peetat Hunan hPL Sisttsssseseses Perpertee vane hotter vt Pete eSsrsessseress Se See. es ae : Stress rake ereae peacetstd eoay . ee pores. oteee tel Ses oS Tye t+ = : isegcteseto-s eer erge et tesco: wn oF mers en seeseS rt" aigipasts rca eeeree esr; Se : Sig hgteseheceees pecenees ee Sir HES i PES IR ee + ee ate ccevenecenesece: Sugeeca i Sosa sslatel ae Pisee3e=e=- taste leséeactastas pite <3 Sesti! 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