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Pig aY¥ a if ES lhe ca So ” ’ md - - i ~ af : Reh Oe ee eae ae ee “ae : 4) ne Hrs ¥ Cae f - ;, PANS hes a bent op SOP ns ® 2 ray a + vad . ‘ % a rr. hg ‘a : eae aM lm) aa ‘ Ane = ,* 4 Le ¥ q “9 : i é - i by > Eo ‘ ' > i my 5 A 3 j Bs = gs es > ey ee «aj 4 as La) aS A JOURNAL OF NATURAL PHILOSOPHY, — CHEMISTRY, &., AND Bom ba Be os VOL. VIII. — Flustrates with Engravings, BY WILLIAM NICHOLSON. — LONDON: PRINTED BY W. STRATFORD, CROWN-COURT, TEMPLE-BAR, ‘FOR THE AUTHOR, No. 10, SOHO-SQUARE; AND SOLD BY ALL THE BOOKSELLERS IN THE UNITED KINGDOM, ‘ SE Rie 1804, ADVERTISEMENT. Tue Authors of Original Papers in the present Volime, are C. Wilkinson, Esq.; Peregrinus . Proteus; A Constant Reader; E. P.; Mr. W. Jones, F. Am. P. S.; Alexander Henderson, M. D.; Mr. J. Haley, Jun.; R.B; Mr. Eze~ kiel Walker; G. A.; I. R. I.; A Correspondent; Mr. Cuthbertson; Mr. J Bramah; Messrs. Harman and Dearn; Mr. Frederick Accum; A Carlisle, Esq.; R.T.3 Mr. J. Dalton; H. G.; Mr. J.C. Hornblower; Mr. John Gough 5 M. le Comte de Bournon; Mr. A. Woolf; Right Hon. Sir Joseph Banks, Bart. P.R.S.; Thomas Thomson, M. D.; Wm. Hyde Woollaston, M.D. F. R.S.; Mr. Wm. Henry; po ae _ Of Foreign Works, H. Beaupoil; Cit. Berthollet; Four- croy; Vauquelin; Collet Descotils; Brugnatelli; Professor Lichtenberg; Ritter; Hauy; J. Drapernaud; Klaproths Van Marum; J. C. Bartholdi; Jerome De Lalande; J. L. Guy Lussac; Dr. P. A. Nemnich. And of English Memoirs, abridged or extracted; R. Ramsden Bradley, Esq. ; Mr. Robert Green; Rev. Edmund Cartwright; Dr. John Winterbottom; R.B.; Benjamin Smith Barton, M. D.; Mr. Edward Massey; Mr. David Charles; Smithson Tennant, Esq. F. R. S. Of the Engravings the Subjects are, 1. Machine of con- fiderable Power for clearing Roads of Mud, by Dr. Winter- terbottom, 2. Mr. Robert Green’s Hand Drill for Peas. 3. The Rev. E. Cartwright’s Three-Furrow Plough. 4. Dia- gram for inveftigating the Figure of the Farth. 5. New Gal- Vvanic ADVERTISEMENT, vanic Apparatus, convertible at Pleasure into one or more Plates. 6. Hydraulic Machine operating by the rotation of two Pinions, in a Water Veffel. 7. An improved Jib for a Crane, by Mr. Bramah. 8. New Filtering Apparatus, by Messrs Harman and Dearn. 9. Galvanic Apparatus. 10. An ancient Lock ufed in Egypt and Western Asia for above three thousand Years. 11. Developement of the Mechanifm of the Lock. 12. Sketch of the Orbits of the New Planets, by Jerome de Lalande. 13. Cryftals of Arseniated Copper, by Hauy. 14. Telegraph by the Human Figure. 15. Ma- chine for levelling the Surface of Land, by Mr. David Charles. 16. Shaded Se€tions of a Clock, which strikes the Hours by simpler Mechanism, and with greater regularity than usual, by means of a Pendulum substituted in the Place of a Fly. . 17. Specimen of a very curious antique Composition or Paint- ing in coloured Glass, by an Art at present lost. 18, Im- proved Lamp for producing a strong Heat in Chemical Ix- periments, by Mr. Accum. . Soho Square, Auguft, 180%. TABLE OF CONTENTS TO THIS EIGHTH VOLUME. a MAY, 1804. Engravings of the following Objests: 1. A Machine of confiderable Power, for clearing Roads of Mud, by Dr. Winterbottom; 2. Mr. Robert Green's Hand Drill for Peas; 3. The Rev. E. Cartwright’s Three Furrow Plough; 4. Dia- gram for inveftigating the Figure of the Earth; 5. New Galvanic Apparatus, convertible at Pleafure into one or many Plates; 6. An Hydraulic Machine, operating by the Rotation of two Pinions in a Water Veffel. I, Letter from C. Wilkinfon, Efq. on the Means of fimplifying and improving the Galvanic Apparatus = - - Page 1 II. Chfervations and Communications on the Dry Rot in Timber, made to the Society for the Encouragement of Arts - - - 5 III. On the Figure of the Earth. By Peregrinus Proteus ~ 12 IV. Defcription and Drawing of a Hand Drill for fowing Peas, Beans, &c. Communicated to the Society of Arts, by the Inventor, Mr. Robert Green, of Weftwratting, Cambridgefhire — - - - - 19 V. Enquiries concerning the Methods of inveftigating the Courfe and Velocities of a Bedy fuppofed to be projected from the Moon to the Earth. By a Correfpondent . ; - 22 VI. Drawing and Defcription of a Three Furrow Plough. By the Rev. Edmund Cartwright, of Woburn, Bedfordthire - - - 24 VII. On the State of Science among the earlier Nations of Antiquity: and more efpecially of thofe Refearches which conftitute the Subjects of Alchemy, In a Letter from E. P. - - - - - 27 VIII. Defcription of a Machine for clearing great Roads from Mud. Com- municated to the Society of Arts, by the Inventor Dr. John Winterbottom, of Newbury, Berks - - - - - 29 IX. Defcription and Drawing of an Hydraulic Machine, with an Account of feveral Inventions of early Date, which have been fince brought forward by later Inventors. Extraéted from a Foreign Work publifhed early in the Jaft Century. By a Correfpondent - - - - 35 X. An Examination of Dr. Wollafton’s Experiment on his Perifcopic Spectacles. By Mr. W. Jones, F. Am. P.S. - = - - 38 XI. Experiments and Obfervations on the Change which the Air of the At- mofphere undergoes by Refpiration, particularly with Regard to the Abforption of Nitrogen. in a Letter from Alexander Henderfon, M. D. - 40 XII. Obfervations and Experiments tending to afcertain the Caufes of thofe Irregularities in Chronometers, which are generated during confiderable In- tervals of Time, and have been afcribed to external Caufes. By Mr. f. Haley, Jun. - - - - - - 46 XIII. A Memoir concerning the Fafcinating Faculty afcribed to the Rattlefnake and other American Serpents. By Benjamin Smith Barton, M.D. From the American Tranfaétions, Vol. IV. - - - 58 Scientific News, 62—Very extenfive Table of Squares, ib»x—On Phofphoric Rings. From a Correfpondent, R. B, 64. JUNE, li JE. TLE N BS. JUNE, 1804. Engravings of the following Objects: 1. An improved Jib fora Crane, by Mr. Bramah ; 3 2. New filtering Apparatus, by Meffrs. Harman and Dearn; 3. Gal- vanic Apparatus; 4. An ancient Lock ufed in Egypt and Weltern Afia, for ~ upwards of Three Thoufand Years ; 5. Developement of the Mechanifin of the Lock. T, Letter from Mr. Ezekiel Walker, on the Metheds of obferving the Longitude at fea; with an Exhibition of the very gveat ACCURAES of the mean Refult from a Number of Chronometers = - - - 65 II, On Galvanifm. By C. Wiikinfon, Efq. ~ - ee 70 UI. On the Formation of Snow. By G. A. - 73 IV. Medico Chemical Refearches on the Vircues and Principles of Cantharides. By H. Beaupoil 76 V. Detcription of a Colvenic Repoee sHordoae a large bee for Oxida- tion, and convertible into one o1 more Plates at pleafure. By I. R.I. 79 VI. On the Difference between the Effects of gaa and of Heat. By Cit. Berthollet - 80 VII. Letter from a Correfpondent I. R,., “i explaining fome Faas i in Galvanifm, and on other Objects - - 84 VIII. On the Preience of a new eet Phoiphate, fauna in the Bones of Animals, which does not exift in thofe of Men. By evareiyy and gh ace Read before the National Inftitute 85 TX. On the Nature of Oxigen, Hidregen, Caloric, Be as deduged from leilvahic Experiments. Bya Correfpondent - - X. Experiments on the Yolk of Wool, falleaned by fome Confiderations on the Cleanfing and Bleaching cf Wool. By Cit. Vauquelin . 90 XI. Copy of a : Letter from Mr. Cuthbertfon to Dr. Pearfon, communicating an important and curious diftinguifh'ng Property between the Galvanic and Electric Fluids. Communicated by Dr, Pearfon - - - 97 XII. Letter from a Correfpondent, containing an Obfervation of the fpontancous Inflammation of Paper in Nitric Acid Gas - - 98 XIII. Defcription of a Jibon a hew Conftruion ; by Mr. J. ‘Bramah, Engineer. Communicated by the Inventor - 99 XIV. A Memoir concerning the Fpipinctins Baculty hick has been afcribed to the Rattle-Snake, and. other American Serpents. By Benjamin Smith Barton, M. D. From the American TranfaGtions, Vol. IV. = 100 XV. Some Account of an Egyptian Lock of very high Antiquity. Indicated from Denon’s Travels. By a Correfpondent. With Obfervations by W.N. 115 XVI. On the Caufe of the different Colours of the triple Salts of Platina, and on the Exiftence of a new Metallic Subftance inthat Metal. By Collet Defcotils. Prefented to the Clafs of Mathematical and oe Sciences of the National Tnftitute of France - 181 XVII. Defcription of an Aepantns for ee Water. ‘By Meff. Harman and Dearn, of Redriff. — - - ~ 126 XVIII. Examination of a Stone ae ie Potafh. By Frederic Accum, Teacher of Practical Chemittry, Pharmacy, and Mineralogy 127 XIX. Letter from A. Carlifle, Efq. on the Temperature of the Sea 131 XX. Obfervations upon the Doétrine of Count Rumford, refpefting the Want of direct conduéting Power in Fluids with eae to Heat. By Cit. Ber- thollet . - 134 ‘XXI. On the Difficulty of obtaining Alumine ina State of Puriips ByR.T. 141 Scientific News, 142—New Earth, i1b.—Suberic. Acid from Paper, ib: —Ealy and expeditious Method of preparing Copal Varnith, ib.—Large Piece of Amber, 143—Fluoric Ether, 1b.—New Method of preparing Nitric Ether, by Brugnatelli, ib,— Accenfion of ee ahaa Hidrogen Gas, by the Affuficn of Nitrous Acid, by Profeffor puma. 144, JULY CONTENTS. ie TUL Y,, 1804. Wharetin of the following Objects : 1. Sketch of the Orbits of the New Pla. nets, by Jerome de Lalande ; 2. Cryftals of Arfeniated Copper, by Hauy; 3. Figures to iliuftrate a Procefs for Telegraphic Converfation at confiderable Diftances, in which the Human Figure itfelf conftitutes the peonnhs 4, A Machine for levelling the Surface of Land, by Mr. David Charles; 5 . Shaded SeGtions of a Clock, wien h ftnikes the Eiginrs by fimpler Mechanifim, miss with greater Regularity than ufual, by Means of a Pendulum fubftituted in the Place of a Fly. ¥, On the fuppofed Chemical Affinity of the Elements of Common Air; with Remarks on Dr. oor s Obfervations of that i see In a Letter from Mr. J. Dalton 3 145 HI. Eafy Methods of completing Tables of Squares and Cubes. In a Letter from H.G. “ 150 XII. Problems in spieroreet "Hianales. i Pa ore: Proteus 151 iv. Defcription of a ftriking Part for a Clock, in ‘welch the Intervals between Stroke and Stroke are not t regulated by a Fly, but ‘by a Pendulum, By Mr.. Edward Mafley 162 V. Defcription of a very fiple Pelearayh, confifting of the Gianh Figure, adapted te converfe at a Diftance by means of Signs 164. VI. Account of a Fa& refpe&ting Water heated in a Boiler oe Stone; with _Obfervations. By Mr. J. C. Hornblower 169 Wil. Fa&ts and Obfervations tending to elucidate the Theory of Galvanifm, By a Correfpondent - 171 VIII. Experiments with the Eleétric Pile by Mr. Ritter of Jena. Communi- cated by Mr. Orfted - 17%6 TX. Account of a Machine for laying Fahd level. By Mr. David Chante 181 X. Experiments on Magnetifm ; by ve Ritter, of chiar Communicated by Dr. Orfted, of Copenhagen L 184, Xi. Obfervations on Arfeniated Copper. By Hauy 187 XII. Obiervations upon the Doétrine of Count Rumford thedttiig the Want of dire&t conducting Power in Fluids with Regard to Heat. By Cit. Berthollet 193 XIII. A Memoir on the Movements which certain Fluids receive from the Conta& of other Fluids. By J. Draparnaud, Curatcr and Profeffor of Natural Hiftory, at the Medicinal Schoo! of Montpelier - 901 XIV. Letter from Mr. Cuthbertfon 4 anes his Galvanic and Eleétrical Experiments - - 905 XV. Chemical Examination of the Getvcite’ a Mineral not hitherto well known, containing a New Earth. By Klaproth = 207 XV4. Letter from Van Marum to J. C. CeCe a on Ritter’s Galvanic Experiments u 212 XVII. Experiments on Light by Mr. Ritter of Jena. Communicated by . Orfted ~ - 214 XVIII. On Spontaneous Le dpaiae ‘By J.C. ba tholdi, Pichia of Phyfic and Chemiftry 216 KIX. Difcovery of Two New Metals in Crude Platina. By Smith Set Tennant, Elg. F.R. S. : Ae 4 220 Scientific News and Account of Books, doa“ of the Orbits of the New Planets, By Jerome de Lalande, ib.—Philofophical Tranfactions of the Royal Society of London, for the Year 1804, Part I. ato, 182 Pages, with 5 Plates and 26 Pages of Metereological Journal, ib.— Analytical Eflays towards pro- moting the Chemical Knowledge of Mineral Subftancess By Martin Henry Klaproth, Profeffor of Chemiftry, &c. 223. AUGUST, iv CONTENTS. AUGUST, 1804. Engravings of the following Objeéts: 1. Secichen of a very curious antique Compofition or Painting, i coloured Glafs, by an Art at prefent loit; 2. An improved Lamp for producing a ftrong Heat in Chemical Experiments, by Mr. Accum. J. On the Pattes, coloured Glaffes, or Enamels, of the Ancients. By M. Klaproth = - = - - - 225 II. On Spontaneous Inflammations. By G.C. Bartholdi, Profeffor of Phyfic and Chemittry - - - 236 III. On the Solution of Water in the Atmofphere; and on the Nature of atmofpherical Air, By Mr. John Gough. From the Author 243 IV. Reply to the Obfervations of M. "Abbé Hauy, on Arfeniated Copper. By M. le Comte de Bournon, Member of ‘the Royal and Linnean Societies of London - Spe - - - 247 V. Procefs for feparating Alumine from Alum. In anfwer to the Enquiries of R.T. By Mr, Frederick Accum - - . 260 WI. Short Account of Mr. A. Woolf's sae in the Conftruction of Steam-Engines - a ae 262 VII. Defeription of a Chemical Lamp, with double concentric Witks, Com- municated by Mr. Frederic Accum - 266 VIII. On the mutual Precipitations of Metallic Oxides. By J.L. Guy-Luffac 270 IX. A Report of the State of his Majefty’s Flock of Fine Wooled Spanifh Sheep, for the Year ending Michaelmas, 1803- By the Right Honourable Sir Jofeph Banks, Bart. P. R. S. &c.e &ce From the prieees Copy com- municated by the Author - - QTT X. On the Oxides of Lead. By ghee Thomfon, se D., Communicated by the Author - = 280 XI. On certain Chemical Effects of Light. In a Letter from Wm. Hyde Wollafton, M.D. F.R. S. - > - 293 XII. Iluftrations of Mr. Dalton’s Theory of the Conftitution of Mixed Gafes. In a Letter from Mr. Wm. Henry, of Manchefter, to Mr. Dalton. Com- municated by the Writer - : - 297 XII. On the Difappearance of Oxigen and iddvech over veered at the Heat of the Atmofphere. ByT.S.T. «= - 30} XIV. Letter from Dr. P. A. Nemmich, exprefling obs with regard to the Death of the celebrated Humboldt : - 303 A JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, AND PER RTS, MAY, 1804 ARTICLE I. Letter from C. Wiixinson, Efy. on the Means of fimplifying and improving the Galvanic Apparatus. To Mr. NICHOLSON. Tue communication from your ingenious correfpondent Introduétion, I. R. I. afforded me confiderable pleafure. As you favoured . — me with his idea how the galvanic power may be increafed to an immenfe degree, prior to its appearance in your valuable Journal, I have been induced to refleét upon various modes of galvanic arrangements. ‘If the whole apparatus be made to confift only of a fingle In apparatus of plate refleéted backwards and forwards, fo as to expofe an ice mai immenfe furface, no plate of copper would be required, only copper is un- taking care, which in this inftance would be eafily effe€ted, eceflary- that one fide of the plate only fhould be expofed to the aétion of the acid. For, from various experiments, J am perfuaded that the other metal anfwers no other eleCtrical purpofe, than to guard and proteét the zine fide, to which it is foldered from being aéted upon by the acid. Even cement anfwers very Cement will de well, if we only preferve through the cement a good con-*$ Well. duéting medium to the zinc. Thus witha zinc plate of eight inches diameter, if only a piece of copper the fize of a half. Vor. VIII.—May, 1804. B penny g IMPROVEMENTS IN GALVANISM. penny be foldered in its centre, and all the reft of that furface, which is ufually foldered to copper or filver, be well covered with cement, equal effeéts would be obtained. Proof in the In a Couronne de Taffes I find the fame effeéts are pro- i tl ¢¢ duced, whether the copper be of a correfponding fize to the : zinc plates, or, whether they be merely fimple copper or filver wires. and in a pile. Upon this principle I have confiru€ted a pile, and find it produces the fame effeéts, as if the whole furface were covered with copper; I purpofe foon to arrange a trough upon the fame principles, and I am perfuaded, that the more tedious and expenfive part of galvanic apparatus may thus be prevented. Thecorrofion in - When a trough has beenfometime employed, upon removing atroughis the plates, the lofs of metal, I always.obferve, does.not take greateft near the : : i aire place uniformly over the furface, but in the upper part, which in the galvanic aétion is the moft expofed to the atmofphere, is the moft aGted on, and towards the bottom, the metal is very little altered. In order te preferve a more equal aétion, I am now preparing a battery formed of plates of ten inches by two and a half, the longeft fide placed horizontally, and f am perfuaded, that this fized plate will produce more ative effets than a plate of five inches fquare. Hence a pileof It is well known, that in every galvanic operation, oxida- | difoes would be tion is produced, and if oxigen can be procured from the preferable. : : : : farrounding air, the effeét would be more eafy tnan producing it from the decompofition of water. I have no doubt, that if a feries of zinc plates formed like large pewter difhes, were to be arranged in a pile-like form, infulated from each other, and the galvanic mixture to be poured in the hollow part; the lower fide being covered with cement, excepting that from the centre a piece of copper fhould be foldered, and fo projecting as to be in contaét with the fluid in the. cavity of the plate below; that a very powerful apparatus would thus eafily be formed. : On the fubftitue In the latter part of your Jottrnal I perufed with a con-. ried pati fiderable degree of furprife, fome obfervations of a Mr. Dyck- mediums by | hoff relative to the fubftitutions of thin ftrata of air, inftead Dyckhoff. of wet media. As the refults of his experiments appeared fo contrary in principle to any I had tried, I immediately re- peated them in the manner he has defcribed, with interpofed 5 lentils {IMPROVEMENTS IN GALVANISN. gq lentils of glafs, fo as torender the feparation very fmall. I then arranged feveral feries of plates of one inch, to plates of feven inchesin diameter; becaufe he has not particularized the fize of the plates ke employed. I arranged piles of thefe different fizes to the number of twenty pairs in each arrangement, and obferved not+the flighteft galvanic effeét, either by my tongue or by any other teft. 1 employed a very excellent condenfer; The experiment no influence at all was evinced; and, lafily, I fubjeGted it to “4 2 Succeed. the moft delicate electrofcope we have, viz. the mufcular fibres of a frog. Not the flighteft difturbance took place, although I fancy I have demonftrated, in the elements of gal- vanifm I have publifhed, that the fenfibility of this animal eleétrofcope is fifty thoufand times greater than that of the condenfer. As to the charging of a Leyden phial, I am convinced it is Conviétion of perfeétly erroneous to fuppofe it has ever been done. I have i dues ice employed from fifty pair of plates to fifteen hundred, and never charge a Leyden yet have produced any charge. Nor indeed could fuch bei? expected from the weak intenfity of the ftate of eleétricity in galvanic operations; for a jar cannot be charged until a fufficient quantum is accumulated to overcome. the refiftance of the furrounding air, fo abfolutely requifite to the charging of a Leyden phial. I am; Sir, Your’s, &c. C. WILKINSON. : ANNOTATION. W.N. THE valuable obfervations in the preceding letter, will Form of gal- naturally fuggeft improvements to thofe who are employed in Me ye the conftruction of galvanic apparatus. It muft be a great i oe advantage, that the expence of copper and the work of foldering, or placing it, will be almoft entirely faved. Fig. 1. Plate Ii. thews a fimple method of difpofing a fingle plate of zine of large furfacein atrough. It is fuppofed to have been made fufficiently hot to bed itfelf in cement at the bottom of the box in which it is placed, and its two ends A and B are fecured in the fame way. The fhaded fpaces reprefent the cavity occupied by acid, and the dotted fpace 4s left empty. _ B2 A com- 4, IMPROVEMENTS IN GALVANISM. A communication may be made by a copper wire from the wet or corroded furface to the oppofite or dry furface, as fhewn at A andC. Another of As it may be difficult to bend a very long piece of laminated fae Eee att- pinc, and to keep it flat, fo as to give it a fecure and clofe fixture in the cement, I fhould prefer a number of ftrait pieces {crewed together with varnifhed pieces of wood between their extremities : every fecond piece being perforated on the acid fide, to permit a free communication. , More particular Mr. Wilkinfon’s pile of difhes promifes to be very effeétual, eae ee and of eafy conftruétion. I fuppofe the difhes to be of zine, either caft in a metallic mould or ftamped, and that each fhould be provided with three fhort copper legs, foft-foldered on 5 after which, the lower face of the difh fhould be well defended by varnifh or cement, and alfo the lower ends, but not the fides of the copper legs. Thus prepared, they might be eafily builded up, and charged by a proper funnel, and an appropriate meafure for dealing out the acid. Galvanic trough In Fig. 2.1 have ventured to offer the fketch of a troughy hea) aga confifting of zinc plates only, principally becaufe it appears a fingle plate, by Capable of being as {peedily charged with acid as another varying the com- trough, and may with facility and at pleafure be ufed either as iis one fingle plate, or as the ufual feries of plates, aéting in fucceffion upon each other. Let A B reprefent a trough con- ftruéted after the manner of Cruickfhank ; excepting that the plates are of zinc only: and let the alternate fhaded cells be charged with diluted acid, while the dotted cells continue | empty. This may, without difficulty, be done at one pouring, by means of a channel in the wooden fide of the trough. Arrangement to Whether this trough, fo charged, fhall aét as one extended Pe a wi galvanic furface, or as a continued feries, will be governed. large plate. by the copper wires of communication. If the former, then a long copper wire having branches defcending from it into every one of the acid cells muft be duly placed; and another wire parallel to, but not in contaét with, the former, and having double branches defcending into all the empty cells, fo as to touch both the dry metallic furfaces, muft alfo be placed. Whenever a communication is made between thefe two principal wires or conductors, the galvanic energy will pafs through the medium of communication. I have not given a diagram, becaufe this difpofition is very obvious. If €URE OF THE DRY ROT. 5 If the latter effe€t be required, namely, that the trough Arrangement fhould a@ like a continued feries, the conneétion of the troughs cat hed aoe al muft be differently made. A number of clipping pieces or plates. {pring forks muft be provided of copper wire, as reprefented by the curved lines a, b,c, d, &c. from each of which proceeds a third leg or branch, as feen in the figure. Thefe are ap- plied (moft conveniently above, but) not fo as to touch each other; the clipping part of each embracing the dry furfaces of a pair of the zinc pieces, which are aéted upon by the fame mafs of acid, while the third leg is immerfed in the acid of the next adjacent cell. Every one of their legs or branches is difpofed towards the fame region or part of fpace; by which means the acid of each compartment aéting upon a pair of zinc plates, on one furface only, is made to communicate, by the interpoiition of copper, with the uncorroded fide of the next pair in fucceffion ; and fo on, exaétly as in the common trough or pile. —-- 2 II. Objervations and Communications on the Dry Rot in Timber, made to the Society for the Encouragement of Arts. (Concluded from p. 318 of Vol. VII.) Second Letter from BENJAMIN JOHNSON, E/y. SIR, ‘Tue obfervations I fent yefterday were taken from different parts of my note-book, in hafte, becaufe the fecond Tuefday in December was paft; for it was by accident I faw the adver- tifement on Saturday ; but withing not to be deficient in infor- mation, I trouble you again. The leaves of the plant appearing exhaufted and dead, is A more full ac- owing to their having imparted all their juices to the wood, Count of the d > : plant that occa- which changed it to a fungus, and not toa powder, like rot- fons the dry tennefs from length of time. rot 5 The Boletus Lachrymans is of the fungus tribe, and is one of the few that have leaves, asthe mifeltoe, &c. - Nothing is more eafy than to prevent the damage from the plant. Befides what I faid yefterday, Iam pofitive that a tile , laid and the method of cure. CURE OF THE DRY ROT. Jaid clofe along the walls round the room, would prevent the growth of the plant, even without mortar; and perhaps it is only neceflary where the walls are next to the air. Charring the ends of the joifts for a few inches, and char- ring the fide of the wainfcot at bottom, next to the walls would be fufficient; for the plant cannot adhere to any thing but wood, and that poffeffed of its natural juices, toa certain degree ; fo that I queftion if old dry oak would receive it. All the white foft woods, as beech, poplars, and deals, are for a long time ready to receive it. Repairing the damage with freth wood, without removing the earth and plant, is only feed- ing the evil. The plant is of the creeping kind, and cannot rife two inches ; fo that wood in all cafes, muft be in contaét with the earth to fupport it. A fungus broader than the palm of one’s hand, and an inch or more tn thicknefs, is commonly feen at the bottom of an old poft, on the furface of the earth; but itis not eafy to difcern whe- ther the wood or the earth furnifhes the matter; fo true is the obfervation of Muller :—** Dans Vétude de la nature, on peut nous comparer a de petits enfans qui commencent ad owvrir les yeux ; nous coulons parler beaucoup, et nous ne faifons que bégayer.” Jam, Sir, . Your moft obedient Servant, BENJAMIN JOHNSON. Ipfwich, Dec. 21, 1799, To the Secretary. N. B. The qualities of this plant are unknown to moft Eng- lith botanifts, as appears from their publications; but they are Known to the Germans, who have habitually ufed more wood in their buildings than we have. EE Third Letter from the Sume. SIR, Affured that the purfuits of the Society for the Encourage- ment of Arts, &c. aim at the full invettigation of whatever they propofe for the public benefit, I cannot perfuade myfelf that I am troublefome in going a little further into this fub- jet. T had CURE OF THE DRY ROT. 7 I bad Jately a converfation with an old friend, who fhowed Some account o me two parcels of rotten wuod, from an oak barn floor, laid caer shina about fixteen years ago. After lying twelve years it fhook upon the joifts. On examination, it was found to be rotted in various parts, and the planks, two inches and a half in thicknels, were nearly eaten through, though the outfide was gloffy, and with- out blemifh, The joifts, and a large middle beam were laid at the ends, in brick and mortar, tocreate a firm level. No earth was near the wood; and he thinks that no air could find a paf- fage. The rottennefs was partly an impalpable powder, of the colour of Spanifh fnuff, and other parts were black, as if burnt; the reft was clearly a fungus. This gentleman isa perfon of undoubted veracity; buta nice It does not ap- and exaét obfervation is neceflary in fuch examinations. He aeclpaker op thought nothing of any plant, and it is likely there was none of any plant, the Boletus; fo that my affertion that it was always to be found, was rather too fyftematic. { afked him if the timber was dry when laid down. He could not however fay that had been particularly adverted to. it had been fawed from a large oak, and was, as he thought, in all refpeéts proper for a barn floor. As this feems not the operation of the Boletus, how did it happen ? We know that the oak, when in vegetation, is fubjeét to On the decay of what I fhall’ call an exudation of juices, which produces the °& timber. fungus, .named the Agaric of the oak, with which the Druids of old played many tricks. The oak, then, if fawed into thick quantities, may emit thefe fame juices, as the progreffive courfe of nature to its entire decay, We have all feen oaks of vaft fize and ancient record, with a great part of the outfide whole, and all the infide gone ; perhaps the work of a century. In all hollow trees fungus is difeoverable. To ufea law term, it isa mifnomer to call it dry- rot; for the rotting principle is in moifture. I had never feen the rot upon fo large a fcale as in timber, The preparation till lately. The prevention, then, of beams, rafters, large a wood for pre- ue f erving it, fhould joifts, and pofts, put into the earth, from decay by the rot, 4 cither char- is in charring only, which will dry up all the fungus juices of ring, wood in large fubftance. Paint, or a bituminous preparation, o» bituminous may probably {top up the pores, and prevent tie rot in flight paint. work, where the treatment I before obferved, with fire, might be incommodious, as in half-inch wain{cot, &c. The 8 Durability of charcoale Tatroductions CURE OF THE DRY ROT. The incorruptibility of charcoal is attefted by undoubted hiftorical fa@s, at the deftruétion of the famous temple at Ephefus. It was found to have been ereéted on piles that had been charred ; and the charcoal in Herculaneum, after almoft 2000 years, was entire and undiminifhed. Iam, Sir, Your moft obedient Servant, BENJAMIN JOHNSON. Ipfwich, December 26. Letter from Ricuarp Ramspen Bramuey, Ef. of Leeds, relative to the Dry Rot in Timber. To CHARLES TAYLOR, Efgq. SIR, I take the liberty of inclofing to your care an Effay on the Dry Rot in Timber, which you will be fo obliging as to lay before the Society for the Encouragement of Arts, &c. Should this Effay be deemed worthy of attention, or fhould any farther notice be neceflary refpecting it, every information that may promote the views of your refpeétable Society will be given with pleafure by, Sir, Your moft obedient Servant, | R, RAMSDEN BRAMLEY, Leeds, Aug. 26, 1799. As the Society for the Encouragement of Arts, 8c. have for fome years offered a premium for the difcovery of the caufe occafioning the dry rot in timber, of which, it feems, no fa- tisfaftory account has yet been received; fhould the following prove fo, it will give the author much pleafure. To bring the matter to the teft by experiments, would require the obfer- vation of a long period, and in feleéted fituations, Wood, ufed.for the general purpofes of man, is cut down at different periods; and although it may be felled at the proper feafon, or when moft free from fap or moifture, it is not al- ways to be effected. : Even admitting it to have been cut down in the moft favour- able fituation, it ftill abounds with fuch an extra proportion of & moifture CURE OF THE DRY ROT, 9 moifture, as to require a regular expofure to the air, prior to Faéts and obfer- its being applied to ufe, if we with to guard againft that fhrink- Yann ene Mis iy ay 5 i g the dry rotin ing which always takes place, where this precaution has not timber, and its been taken. patie Although the fir kind contains lefs of this watery portion, yet it affuredly poffeffes a confiderable fhare ; and it is in this {pecies, I apprehend, thatthe evil called the dry rot moft ge- nerally occurs, as from the facility of working the fame, it is moft generally applied in buildings. But fuppofing it to be fir, or any other f{pecies ; wood felled when abounding with any extra proportion of fap, and applied to ufe without the proper feafoning or expofure to a free current of air, until fuch extra moifture as has had time to exhale, is moft liable to the difeafe in queftion ; and the cure, or principal _ prevention againft it, would be the precaution of felling all wood only at the proper feafon, or when the fap is not in cir- culation, The next mode of prevention would be to ufe {uch wood only as has been for a confiderable period expofed to the influence of a free current of air, or where convenience will admit, to that of air heated to a moderate degree; fuch air ex- traéting with greater facility the inclofed moifture, and in a more certain ratio than the irregularity of our atmofphere will allow. : In all rapidly-improving countries, this evil is likely to be an increafing one, as the current demand for wood generally ex- ceeds the fupplies laid by in ftore, fo as to be applied to ufe in regular fucceffion, after being properly feafoned. Another caufe that affects all wood moft materially, when not fully dried, is the application of paint, the nature of which prevents all exhalation, and confines the inclofed moifture, till it occafions a fermentation through the whole fibrous fyftem of the wood, and brings on a premature ftate of decompofition, or the dry rot. A fimilar evil may be induced, in confequence of any newly- finifhed building having all the doors and windows fhut up, and that for fome length -of time, particularly in moift weather, The wood, even though unpainted, is thus frequently placed in an atmofphere more charged with vapour than its own inter- nal contents, and is confequently in an imbibing inftead of an exhaling flate, and tending to decay. Wood placed in damp- ifh fituations, and the ends of timbers near to moift walls, fuffer from fimilar caufes. What 10 Fats and obfer- vations concern- ing the dry rot in timber, aid ats cure. CURE OF THE DRY ROT, What particularly attra@ted my obfervation to the: circum- ftances was this, that both oak and fir pofts were brought into this premature ftate of decay, from their having been pain- ted prior to the due evaporation of their moifture; and then extending the obfervation, and tracing the hiftory of other wood affeéted in a fimilar manner, I am convinced that the evil frequently thus originates, and its prevention would be in ufing timber, previoufly well dried and feafoned. RICHARD RAMSDEN BRAMLEY. SIR, A confiderable time has elapfed fince I furnifhed you with fome obfervations relative to the dry rot in timber, and having been fince engaged bufily in draining from 4 to 5000 acres of ground, further ideas on the fubjeét of the dry rot have in the interim recurred to me from the work I have been engaged in, which, if the refpe€table Society towhich you are Secretary think worthy attention, they may add to, or conneé with my former ideas, as may be deemed moft ufeful. Where houfes are troubled with damp walls, near to the earth’s furface, it is generally, if not univerfally, occafioned by the percolation of water from the higher adjoining ground, which, thus in- tercepted in its current, attempts to follow the general hydrof- tatic law, of elevating itfelf, by the fyphon line, to a height equal to that from whence it has its origin, Thus, in houfes differently fituated, we fee the damp arifing, to varying de- grees of height, on the walls; and thofe are probably all cor- refponding to the height at which the moifture circulates in the adjoining ground. At its firft entrance to the building, and whilft the moifture is in {mall quantity, the excavated part of the foundation wall may abforb, and gradually quit fuch proportion ; but the excefs, as is generally the cafe in moift weather, exceeding that power, the foundation ftones are then faturated in a more rapid proportion than the adjoining rarified internal atmofphere can evaporate: the watery particles then creep up, in degrees proportionate to the afcent from which they originally defcended, excepting when prevented, or driven off by the fuperior heat of the adjoining rooms, when, in addition to the difagreeable damp they caufe, they fre- quently occafion confiderable damage to piétures, furniture, &c. Drains laid out athwart the afcending ground, witha emery CURE OF THE DRY ROT. ll! very flight defcent or fall, and made of the depth of one yard Fats and obfer- for each yard of afcent, and from the foundation until equal deena to the height that (uch damp ever rifes, would, there is little in timber, and doubt, completely fecure the houfe and furniture from the its curce inconveniences hitherto fuftained, and would generally prove an effectual prevention to moft cafes of the dry rot, where it originates in extreine moifture. Iam of opinion that the fun- gus which pervades decaying wood is not the firft caufe, but an attendant on the peculiar ftate to which fuch wood has been reduced by prior caufes. The diffeminated feeds finding a ‘proper bed, or midus, like the mufhroom, toad-ftool, &c. fix there their abode, and pervade the whole fubftance, thus ac- celerating the general law of Providence, which tends tomake all matter re-produ@tive. Cellars, or fuch other places, fhould be drained in the man- ner I have above mentioned, by taking off the percolating water, prior to its gaining. admiffion to or contaé with the walls; and it is probable that, in moft cafes, a fingle drain will have complete effect ; it would affuredly do fo, if it was not for the yariation of the earth’s internal ftrata, which are not eafily difcernible. If attention to this rule was paid prior to the-building any new ftreets in towns, it would prove ef- fentially ufeful. Iam, with efteem, Dear Sik, Your’s truly, Leeds, June, 1803. R. RAMSDEN BRAMLEY. To Mr. Charles Taylor. The Society have been informed, that mortar made of lime from burnt chalk is much more deftruétive to timber than ftone lime, or that burnt from lime-ftone. Chalk lime attraéts moif- ture; and communicating it to any timber which it touches, oc- Cafions its decay.. | Sea fand is alfo prejadicial, if made into mortar, from a fimilar quality of attra¢ting moifture from the atmofphere: this may in fome degree be corrected by wafhing the fand well in frefh water, where good fand cannot be procured. - Good mortar, where any is required to be in contaét with fimber, may be made from a mixture of ftone lime frefh burnt, and 12 Obfervations upon Profeffor Play fair’s memoir on the figure of the earth. ON THE FIGURE OF THE EARTH. and river fand, towhich a very {mall quantity of common brown, or yellow iron ochre, fhould be added, and well incorporated therewith. a BS HI. On the Figure of the Earth. By PereGRINUS PROTEUS. To Mr. NICHOLSON. SIR, In fome of your late Journals I obf{ervea paper on the figure of the earth, by Mr. John Playfair, profeflor of mathematics in the Univerfity of Edinburgh, containing feveral new the- orems, and ingenious remarks, ona fubjeét which has engaged the attention of the firft mathematicians of Europe fince the days of Newton. Onreading it, I was led to examine the properties of {pheroidal triangles, and to inveftigate the pro- blem, propofed by the author, for determining the dimenfions of the earth from the length of the ftraight line or chord join- ing two places whofe geographical fituations are given. Thefe are intended to form the principal fubje€& of this letter; but, before I proceed to them, I beg leave to make a few obferva- tions on that paper, without any view to cavil, or detract from its real merits. After taking notice of the difagreement in the compreffions of the terreftrial fpheroid, which refult from the comparifon of different meafurements, he affigns, as the principal reafon for this inconfiftency, the local irregularities in the direétion of gravity, arifing in fome fituations from the attraCtion of moun- tains, and in others from the unequal denfity of the materials under, and not far from, the furface of the earth. That the firft has a fenfible effect on the plumb-line has been proved by accurate and undeniable experiments ; the fecond is an ingeni- ous and probable conjeCture, which the furveys carrying on in Great Britain and France will afford data to refute or confirm. But though the former may operate in the general furvey of a country, where the obferver has not his choice of ground, it has always been avoided as much as poflible in meafurements made for the exprefs purpofe of determining the figure of the earth; and though the latter may produce fome perceptible difference ON THE FIGURE OF THE EARTH. 13 difference in obfervations made in nearly the fame latitudes, Obfervations does the author think it fufficient to account for the great dif- 5° eae agreement in the refults from the comparifon of diftant obfer- memoir on the vations? Is it not much more probable, without giving up the rm of the elliptic figure, that fome of the obfervers may have ufed dif- ferent ftandard meafures from the reft, or not made proper al- lowances for the alteration of their lengths in different temper- atures? In fhort, this circumftance appears to me fufficient to account for fome fmall local irregularities, but wholly inade- quate to explain the great differences in the general refults. The author then proceeds to point out feveral methods of calculating the dimenfions of the earth from terreftrial meafure- ments. ‘The firft applies to the cafe where two arches of the meridian are given in different latitudes, which, under the moft favourable circumftances, is incomparably the moft accurate that can be employed, The rules he gives are certainly very fimple, and in fome refpeéts new; but he feems to be mif- taken when he afferts, that the calculation muft be made by rules quite different from thofe that have been hitherto given. Euler’s * is effentially the fame with his own; and Du Séjour, Legendre, Delambre, &c. have given many accurate theo- rems, which may be applied to this purpofe. The fecond me- thod is, from comparing a degree of the meridian in any lati- tude with a degree of the curve perpendicular to the meri- dian in the fame latitude ; and the third from the meafures of degreesof the curve perpendicular to the meridian in differ- ent latitudes. His theorems for both are very accurate and fimple. But the principal novelty of Mr. Playfair’s paper is, the method he propofes of finding the figure of the earth from the length of a ftraight line or chord joining two places whofe geographical fituations are given. As he has left the folution _ of this problem to fome future occafion, the following perhaps may not be unacceptable ; Let PAO (Plate III. Fig. 1.) reprefent one quarter of the Solution of the ellipfis, by the revolution of which round the femi-conjugate aaa axis PC, half the terreftrial fpheroid is generated. Let C figure of the be the center of the earth, P the pole, C O the radius of dae from the A ength of achord equator=a, C P half the polar axis =), and c=the compref- joining two fion at the poles, or the excefs of a above b, Let A in the known places, Co ® Memoires de L’Academie Royale des Sciences Belles Lettres a Berlin, 1753. meridian 14 ON THE FIGURE OF THE BARTS; Solution of the meridian PAO be one of the extremities of the meafured chord, problem for finding the figure of the earth from the length of achord joining two known places, Co and B in the meridian P B the other extremity ; let AD, BF be drawn perpendicular to CP, BE perpendicular to the plane CPAO, and let AB, AE, FE be joined. ‘Then wilt AE? be=(CD—CF)* -+(AD—FE)?=CD?-+-AD? x CF? 4 FE?—2CDxCF—2ADx¥E, and AB? =AE?+BE2 = CA?-+-CB*—2 CD x CF—2 ADx FE. Now let a, ? be the latitudes of A and B expreffed in deci- mals of the radius 1, » the difference of longitude or theangle. . BFE, and D the length of the meafured chord=AB. Then from the properties of the ellipfis we have a? cof. .a7-+-b? fin. a? 7 ot dug! ; : ae "a2 cof, A762 fin. a? =a? — 2ac Sina a” cof, » =e iy aE EN ne we tie oe Beka col. 2.7 4b? fin. A?) aco +c col. 4 fin. A° ries a =a fin. _—c fin. a J (a col, A7+-b? fin, A*) (2—fin. a7), neglecting the powers of e ‘higher than the firft, -becaufe c is very {mall in comparifon of a. Whence by fub- ftitution, and putting 0? = 2 a? (1—fin. ® fin. A—cof. @ cof. a cof, v), we obtain the following equation; y2 37—c (4a (fin, A—fin. 8 iow (fin. 2® + fin. $7) Jeb: and by extraéting the fquare root of each fide, and rejeéting the fquare, cube, &c. of c, there refults, 2 3 : Ie} = (fin, A— fin. 9)? — = (fin. A” + fin. o*) | ap, mt or ate } t (fin. 2 a fin. 97) = (fin, a—fin. $)? \ = This equation may be otherwife exprefled thus ; let a {phe- rical triangle be conftructed, having two fides equal to the polar diftances of A, B, and contained angle = their difference of longitude; whence find the third fide, which put = 3.’ - Then will fin. @ fin. A +- cof. @cof. x x cof.» = cof. 4, and 1—fin. ¢ fin. 1 — cof. 9 cof. cof. w = 1—col. 3 = 2 fin, 292; therefore 3 = 2a fin. 29, and D=2a fin. 134+¢ } fin 19 (fin. A—fin. %)? z oe (fin. x fin. 97) fin 2 es The value.of 3 ~ is manifeftly equal to the length of a ftraight line joining two places, whofe latitudes are A, ?, and difference of longitude w, ona f{phere, whofe radius is a. From ON THE FIGURE OF THE EARTH. 15 From this equation the following method of determining the Solution of the problem for figure of the earth is deduced. Let /be the length of a mea- § ang the dured chord, and.a, ¢, w the latitudes and difference of longi- figure of the * Be 2 an 219 earth from the tude of its extremities ; find 4 as above, and let m = 2 fin. 24, Stee a (fin. a—fin. @)?. joining two and n == fin. i4 (fin. A aa fin. $7) ar ih a known places, e . . ye S&C. Then if we rejeé all the powers of c higher than the firft, we fhall have the fimple equation ma +-ne = J. In like manner find a fimilar equation m’a 4-n'c =I’, correfponding to any other chord whofe length is ’, and there will refult a = / 7 le i; n’l — nl m'l—ml Sle —_——’ and ce =——-———.._ The approximation may be mn — mn mn —mn eafily carried further by including the fecond power of c, and thus finding an equation of the form ma +-nc + pe 2=/; but this labour would be ufelefs, as the method itfelf does not ad- mit of greater accuracy. If ¢=a the equation becomes a= a+c fin. 9?, as isfound by Mr, Playfair in § 31. From the firft equation a rule may be eafily derived for cal- culating the difference of longitude of two places, when their latitudes and diftance are given. For by tranfpofition we have e2 (1 + — (fin, Az + fin. $7) = D* + 4ac (fin A—fin 9%)”, and by divifion, and reje€ting the powers of ¢ higher than the firft3* ==D? + (4a? (fin —fin.9)*—D? (fin. 0? fin. )): but 3% is == 2a? (1—fin. a fin. ¢@—cof. a cof. @ cof. #), there- 1— —-—fin. a fin. g ae < (2 (fin. a—fin. 9)? 4 fas Z =—=—— Dp. A—fin. a= fore col. » = —~Sar eg 7g (2 (fin. fin. 0) 2 D? ; D Sa (fin, a? + fin. ¢)) and putting 1 = oen fin. a fin. col. a col. 9 Dz 2 (fin. a — fin. o)* — — : / pit c a* = cof. .’ we have = o’ +— x a . fin, a’ , (fin A* -+- fin. 07) ~y which rule may be thus expreffed. Let there be a fpherical triangle, having two of its fides equal to the polar diftances of the places, and the third fide d fuch that fin, 16 ON THE FIGURE OF THE EARTH. Solution of the D problem for fin. 3d = ——=: find the angle w” contained between the polar finding the 24 figureof the —diftances, and the difference of longitude » will be = w’ ++ earth from the lbnath ofa chord 2c x cof, $ d? (fin. a? + fin. $*\—2 fin. a fin ?, joining two a fin. wo’ — ia The latitude % may alfo be found from the fame equation, when a, wand D are given. For if the bafe of a fpherical triangle be = d, the two other fides = 90°—a, 90°—9’, and the contained angle =, the cof. w will be = D2 a a fin. a fin. oy) ot a - Now let ?=@ +42, where x muft be very fmall, and cof. 4 cof. ¢ there refults cof, w = cof. w ++ (cof. a fin. %’ cof. » — fin. a cof. ¢) cof, a cof. o’ (cof. a fin. 9’ cof. » — fin. a cof. 9’) cof. A cof. 9 (2 (fin. A — fin, iP (fin. A* ++ fin, 9/7) ) nearly, x fin. x: confequently c fin. x == — ‘~ a c andyxy=-~x a cof, Acof. 9’ (2 (fin. A—fin. o’)® — oe (fin. 7 +- fin. 9/2 ) @ cof. a fin. 0 cof, « — fin. a cof. 0’ From the inveftigation of Mr. Playfair’s problem, therefore, we have obtained very accurate rules for finding » from a, 9 and D, and ¢from a, w, D. Now in order to find an equation expreffing the relation be- tween the latitudes, difference of longitude, and one of the azimuths, let AL be perpendicular to the meridian PAO in A meeting FE in L, and BK perpendicularto AL. Join KE, and the angle BKE will be equal to the fpheroidal angle OAB, and BFE equal to the angle APB or difference of longitude. Let OAB= BKE = A, BFE =», and a, $as before, then will LE be = (CD — CF) cotang. a + FE — AD, KE= (CD— CF) cof. 4 + (FE— AD) fin. 4, and cotang. A =e Whence by fubflituting the valves of CD, CF, AD, BF given above, and rejeéting the powers of c higher than the firft, there refults ON THE FIGURE OF THE EARTH. 17 cof. ? fin. a cof.w—fin. 9 cof.rA 2c , Solution of the refults cot, A= nat @ Winton a pi om nding the — of the ekeelin sO) col.r. But if # be the vertical angle of a fey the col. ? fin, # length of a chord {pherical triangle, and 90°—@, 90°— a the fides; alfo A’ joining two the fupplement of the angle oppofite the fide 90°— 9%; then rae placesy cof. ¢ fin. piel w— fin. cof. a col. ? fin, 3) ». 2c , cof.a (fin. A — fin. 9) quently cot, A= cot. A= Ocha will cot. A’= > and ne Whence as A, A’ are nearly equal, we obtain A= A’ + —< cof. a (fin. 4 — fin. ?) cot. @ col. w abundantly accurate in praétice, but if the fquare of ¢ be re. 2 fin. A’? cof, a (fin. A — fin. ?) oy Bh Mrdcee Pinwe i aie oe OT _ fin. A cof. 24 +2 fin, a fin. ¢% —fin. cof. > fin, w Qfin. A’ x 9 which will be found tained, and and fin, A’* cof. 2 x Z —cot. ab A will be = A’ + M x — —N x — more accurately, The rule may be thus bt ida, let ‘the colatitudes of the two places, and their difference of longi- tude form the fides, and contained angle.of a {pherical triangle, of which find the bafe angle at the place whofe latitude is a, and let it be—=~’, and the hie scegche angle « of the Ipheroidal triangle will be = a’— - = x 2 fin, «/* x cof. A (fin. A — fin. 6) cof. @ col. w the {pherical triangle at the place whofe latitude is @, the cor- refponding angle of the {pheroidal triangle will be found to Bs ns ahaa v5, ., col. > (fin. @—fin. a) , be= 8 q Xx fin. x fen abel teal ak Con- Bes pe Sa) Gitex —- sins © Bee en Rea A cof. @ cof. w cof. cof. 9 (fin. @— fin. a) = cof. Acof,a *. In like manner if 6’ be the angle of x 2 fin. a’? cof. Aeagcs x 2 fin. Cats a Cc oe! + B— Palsy: 2 (fin. «/?.cof. »” — fin. B* cof. $7) (fin A — fin. ¢) bist Bp cof. A col. ? coi. 3 Vor. VIII.—May, 1804. C fpherics 18 ON THE FIGURE OP THE EARTH. Solution of the fpherics fin. «’ cof. A= fin. 6’ cof.o, therefore « + P= on +-(¢ apart Se _ if we reject the powers of c higher than the firft, which’ are figure ef the infenfible. Hence the principle laid down by Mr. Dalby, viz. rae fromthe that in a {pheroidal triangle, of which the angle at the pole ength of a chord 5 joining two and the two fides are given, the fum of the angles at the bafe. Pi places is the fame as in a fpherical triangle, having the fame fides, Co . . . and the fame vertical angle, is verified, and'therefore the con- cluding remark of Mr. Playfair is hafty and ungrounded, But perhaps Mr. P. in his folution retains the fecond power of c, and objeéts to. Mr. Dalby’s principle becaufe its coefficient does not vanifh except in particular cafes. If fo, the objec- tion is frivolous, as the difference is fo {mall as fearcely to be computed in the cafes that occur in pra@tice, and too {mall in any cafe to lead into error or deferve attention. The preceding theorems for the folution of fpheroidal tri- angles will be found extremely accurate, when applied to fuch as are defcribed on the furface of the earth, on account of the fmallnefs of c in comparifon of @; and in like manner others may be deduced, when different parts of the triangle are fup- pofed given. Thus if a, « and D be given; let a fpherical triangle be conftruéted with one fide = 90° —a, another=d, D : fuch that fin. $ d= ai and the contained angle =a; find , a / the other fide 90 — ¢’, the angle at the pole w’, the other azi+ muth 6’ and we fhall have equations of this form @=@ + Pc,» = wv +.9%c, andB = +. Rc, where P, Q, R are func- tions of a, «, D, which may be derived from the foregoing equations by proper artifices, But the formula, except in particular cafes, will not be found fo fimple as the former. Thefe, however, and fome new theorems applicable to trigo- nometrical furveys, I fhall delay to fome future communica- tion, In the mean time, it may not be foreign to the fubjeé to Arch of the - remark, that the arch of the meridian, faid to have been lately hon popeaicr meafuredin the Myfore country in the Eaft Indies, by Brigadier Myfore country, Major Lambton, gives the degree, in latitude 12°.32’N. equal to 60494 fathoms; which compared with that of 60795 in la- titude 47°,24’ N. gives .4, for the compreffion at the poles, a quantity differing very little from the mean deduced from all the meafures of degrees. But it muft be confeffed that there appear at prefent to be two very important objeétions againft the accuracy of Major Lambton’s meafure. The Myfore, on account DRILL FOR SOWING PEAS, 19 account of the irregularity of its furface and its uncertain ele- vation above the level of the fea, is an unfit country for afcer- taining a nice point of this kind, however well fituated for —perhaps in conneéting the eaftern and weftern fides of the peninfula by a oy helt gas geographical furvey ; and the Major, from his account in the caufes ftated, Tth volume of the Afiatic Refearches, feems to be fomewhat doubtful of the exaét length of his chain. Neverthelefs it is probably to India that we muft look for the means of finally de- ' ciding this long contefted queftion. There, and there only, we find many traéts of country highly favourable to this pur- pofe; and it is to be hoped that the Eaft India Company, while anxious to afcertain the extent of its poffeffions, will not en- tirely negleé the interefts of {cience. “ “Tam, Sir, .&c. : PERIGRINUS PROTEUS. Portfmouth, April’ 7, 1804. ee oe IV. ie Defeription and Drawing of a Hand Drill for fowing Peas, Beans, &c. Communicated to the Society of Arts, by the Inventor, _ Mr. Rosarr Green, of Weftwratting, Cambridgefhire*. To CHARLES TAYLOR, Efq. SIR, [ HAVE invented an engine to fow peas, with which I have Very economical fown all my peas, to the amount of 40 acres, at the price of 1s, aril! for fowing per acre, and think that my peas are much better than thofe**” fown any other way. It is alfo on a very fimple plan, and the = expence of it when complete is not 2/. It is ufed by manual labour, without any horfe; and it will draw the drill, fow the peas, and cover them at the fame time, and will fow them “much rounder than any other I have yet feen. I likewife find Ican doit much cheaper than with any horfe, and am of opi- * To whom the filver medal and ten guineas were voted by the Society. A complete machine is placed in the repofitory of the Society, C2 nion 20 DRILL FOR SOWING PEAS, Very economical nion that it fows much better than any drill I have feen. If drill for towing peas. the Society with it, I will fend a model for their infpec- tion. | Iam, Six, Your obedient Servant, ROBERT GREEN. Wefiwratting, Cambridgefhire, June 27, 1802. SIR, I wave fent the engine for fowing peas, in order that it may be laid before the Society for the Encouragement of Arts, &c. J intended to have fent a model of it, but afterwards thought that the engine itfelf would be more acceptable to the Society. I made it myfelf, and have fown with it 26 acres of land in my own occupation. Mr. Piper, a near neighbour of mine, has fown-with it five acres; and Mr. Cock, of Blunt’s Hall, Wratting, in Suffolk, 25 acres, at the expence of 1s. per acre. Several other gentlemen had drills of me for fowing peas. If I give my men Is Gd. per acre, they will fow for me two acres in one day. I can with my own hand fow one acre in five hours, and at the fame time fow the peas, draw the drill, and cover them, and make full twelve drills and a half to the rod. ‘I likewife produce the plant much handfomer than any other feen in our country, and at avery trifling expence. By this too, the labour of horfes is fpared, which we find to bea very material circumftance. It will be a moft excellent engine for gardeners in the neighbourhood of London; for I will be bold to fay, that no man can fow with his hand, fo as to equal this, at a very trifling expence. I have fpent much time in making implements of ‘hufbandry, but have made none fo ufeful as this; for it is fimple in its con- ftruétion, may be purchafed by any man, the expence being fo trifling, and faves the labour of horfes. I remain, Sir, Your moft obedient Servant, Weftwratting, ROBERT GREEN. Defcription DRILL FOR SOWING PEAS. Do} _ Defeription of the Engraving of Mr. Rosert Green’s Hand- Very economical Drill, for fowing pce, Beans, &c. Plate II. sent fowing Fig. 3.a a, The wheels placed upon a wooden axis 6, which is {quare at each end, but round in the centre. The fquare ends of the axle have holes throughout them, at different dif- tances in order to depofit the feed at nearer or more diftant in- tervals, as may be wanted. c, The box in which the feed is placed: the axis 6 is cylin- drical, and has holes made therein proper to receive the feeds, which by the revolution of the axis are carried forwards, and fall through an iron tube into the ground opened for them by the fhared, When depofited in the ground, they are covered, or the earth drawn over them by two iron pins or fcrapers é, fixed on each fide of the tube, and extending fome inches behind it. Sf, The handles of the drill-machine, by which it is pufhed forwards. Fig. 4. Shows an enlarged view of the interior of the feed- box c, above mentioned, and holes for the feeds placed in a fpiral line, in order to drop the feeds more regularly. g, Isa fmall brufh within the box, which rubs againft the cylinder, to keep the holes clear to receive the feeds. Fig. 5, Is a fe€tion of the machine, where a is part of the feed-box ; 6, the round part of the axle, which aes the feed. d, The thare which opens the earth, h, The tube through which the feed falls. z, The mouth of the tube, and one of the fins which draws together the foil, and covers the feed. k, Is afmall door, to be opened occafionally, if the roller or tube are out of order; : l, A ftrong flat board, to which the iron work is fcrewed, ' Fig. 6, Shows an enlarged plan of the iron work, when the machine is reverfed, d, Is the fhare, 2, The hole from which the feed is dropped. ee, The two fins, or f{crapers, which colleé& the earth and cover the feed, N, B. 99. PROJECTILES FROM THE MOON, N. B. The length of the upper rim of the feed-box of the machine in Fig. 3, being fifteen inches, will ferveas a ftandard for the meafure of the other parts La V. Enquiries concerning the Methods of inveftigating the Courfe and Velocities of a Body fuppofed to be projected from the Moon ta, the Earth. By a Correfpondent. To Mr. NICHOLSON: et Theory of La Aone the various theories concerning the ftones fallen a roe upon the earth in different parts of our globe, (the fubjeéts of the moon. Mr. Howard’s Analyfis), that which De la Place has ventured upon, though apparently incapable of proof, feems the leaft improbable, namely, that they are projections from the lunar volcanos. Surely, Sir, whether this is or is not pofible, may be mathematically demonftrated, certain data being allowed. If you, or any other able mathematician, could find time to do this, it would be a great gratification to fee the folution of thefe queftions. . Data forcompus We mutt affume as data, That the denfity of the materials ion. compofing our fatellite, is precifely fimilar to the denfity of our globe; and that the moon has no atmofphere to refift the projection from its furface, or fo fmall a one as not to be cal- culated upon, fince, probably, it is rare and low, perhaps not more than one-fixth of a mile high. _ Now their relative bulks and diftances are pretty well afcer- tained, and we will take them to be preci/ély known. Their comparative centrifugal forces may eafily be calcu- lated, as the moon revolves about 27 times flower oe its axis than the earth about hers. Thefe points muft be fettled, becaufe particularly the laft muft have confiderable effe&t in determining the line Leg pro- jeGted body would deferibe. * This account was alfo fupported by a certificate from eight perfons who had ufed the drill in fowing 113 acres of land, and of eleven farmers who witnefled and approved i its operation, a FROJECTILES FROM THE MOON; 93 Let us fuppofe too, that this body weighs one hundred weight, ’ What will be the velocity requifite to overcome the mutual Refults to be in. attractions of the moon and this body, foas to project it beyond weaned their powers ; remembering that its velocity will be continually diminifhing as long as any attra€ting power aéts upon the pro- jeGtile, and calculating the aid it would receive from the cen- trifugal force, In the journey of 240,000 iiles through which it has to tra- vel in a direét line, is there any free Gece beyond the {phere of the moon’s attraétion and that of our planet’s? If fo, at what diftance from the moon will that be found? and at what dif- tance from the earth? and with what velocity may it be fup- pofed to travel through that fpace? of courfe it will be much flower than when firft projected. As upon entering the limits of the earth’s attraétion its velo- city will be again increafed, quere its rate of travelling to the earth; and, taking the three reckonings into account, in how many days and hours can it be mathematically demonftrated that it would reach our folid globe? Acted upon by the united forces of projeétion, centrifuge, {if I may coin a word) and the motion of the moon in its orbit, and the force of attraétion and orbital motion of the earth, what will be the precife line it may be prefumed to defcribe i in its courfe? Would it not have a revolving motion during fome part of its courfe? What are the calculations by which we may be enabled to “judge that 3 or 5 times the velocity of a cannon-ball, at the moment of projection, would econ it to counteraét thefe im- pediments? It has furprized me, that the numerous late publications men- tioning this theory, have not detailed the mathematic procefles ‘by which it feems capable of being folved, or of proving its fallacy. I hope, Sir, you will not think this obtrufion impertinent. You obligingly and fatisfaétorily complied with my requeft in a note concerning Col, Blaquiere’s gun to throw double headed fhot ; this has emboldened me to exprefs my withes on the fubjeét _ of this letter. But I do not wifh to have my ignorant queftions load Ok THREE-FURROW PLOUGH. load your valuable Journal, though I fhall feel myfelf much obliged by any further information upon this head. | I remain, Sir, Your moft humble fervant, A CONSTANT READER. ————————>—>>—>>>—>>>=——>E>>E>EE>EEeyxvxlx7_l] ~——~>>>>l—S—>S>[>[l—SSSS===s VI. Drawing and Defcription of a Three-Furrow Plough. By the Rev. Envmunv Cartwricht, of Woburn, Bedford/hire,.* To CHARLES TAYLOR, Efg. DeEaR SiR, Economical I ENCLOSE you a certificate of the performance of a plough oe of my invention, which has occafionally been at work through ibis the whole fummer. For this laft fortnight, it has been ufed for ploughing in wheat under furrow. Though a very ufefyl inftrument at all times, it is particularly valuable at the feed times, and the turnip feafon; becaufe at thofe times it fre- quently happens you lofe the moft favourable opportunities, for want of ability to execute your operations with fufficient difpatch, Weekly faving | I need not calculate to you the faving on the ufe of this plough, ql. 166. It is worked (on light land I mean) with a pair of horfes, without a driver. A pair of horfes and a ploughman cannot be laid at lefs than 8s. per day. As two fets of thefe are faved, the weekly faving by the ufe of this plough amounts to no lefs than 4, 16s. Applicable to Ufeful, however, as I find this inftrument on our light level level lands ina Jands, I am not fo partial to it, to fuppofe it is equally calcu- nat a nite lated for all foils, or all kinds of ground, For inftanee where : the ground is very uneven, or the ridges are narrow and fteep, I would not ufe it; neither when the land is very foul with root weeds. In all thefe cafes a fingle plough is certainly to be preferred : but in all cafes where the ground is in a tolerable ftate of cultivation, and where it lies reafonably level, it will _ be found a moft valuable acquifition. * From the Tranfaétions of the Society of Arts, who voted him the filver medal. A model is placed in their repofitory. I will THREE-FURROW PLOUGH. 25 I will thank you to communicate this letter, and the certifi- cate accompanying it, to the Committee of Agriculture; and and if they are difpofed to think favourably of this invention, { will fend you a model for their infpeétion. Iam, Dear Sir, Your very obedient fervant, EDMUND CARTWRIGHT. Woburn, Od. 20, 1802. ene iat eee This is to certify, that the three-furrow plough invented by Certificatey the Rev. Edmund Cartwright, ploughs a furface of twenty- feven inches each bout, and that on light land a pair of horfes regularly ploughs three acres per day with it ina workmanlike manner, JOHN DUCKITT, as Bailiff to his Grace the Duke of Bedford. WILLIAM BAXTER, Afifant, Jme 21ft, 1802, a Dear Sir, YOU herewith receive the model of my three-furrow why this plough plough, faves powers The faving of hands, and confequently of expence, in a plough of this kind, is obvious; but why there fhould be a faving of power, may require to be explained. I need not obferve to you, nor to any man who confiders the action of a common plough, that a very material part of the labour in ploughing, arifes from the fri€tion of the land fide and the fole; of the cneagainft the fide of the furrow, of the other againft the bottom, In a fingle plough a certain length and width are required in thofe parts of it, to make it go fteady ; and even then the effect would be imperfe@ly obtained, did not the ploughman affift by the leverage of the handles of the plough. Hence itis clear, that the lefs difpofition any plough has to follow the draught in a ftrait line, the greater is the labour of working it, becaufe the ploughman in that cafe is to exert a greater power of leverage to keepit fteady. On the contrary, when two, three, or more ploughs are combined, they ferve to fleady each other, and require comparatively very little power of the lever to keep them ina ftrait line. Under thefe circumftances, 26 Economical three-furrow plough. Defcription of _ Mr. Cart- wright’s three- furrow plough. ' THREE-FURROW PLOUGH. circumftances, neither the firft nor fecond plough has any fole or land-fidé whatever ; and even the third does not require fo much of either as a fingle plough. I-calculate the faving of power from the confideration alone, as equal at leaft to one ‘ plough. What farther power is faved, I attribute to the ait nefs and compactnefs of the inftrument, I am willing to think the fimplicity of its conftruétion, and the manner of fixing the plough (confifting but of two parts) to the beam, will not efcape your obfervation. When the cutter (for as it is both coulter and fhare, I can give to it no other fingle name) requires to be fharpened, or new-laid with fteel, by drawing the two bolts the whole is fet at liberty. I make the ploughs to fit each beam indifcriminately ; becaufe when the land is too ftrong, or too foul, to work the three, I take off the fecond plough, and transfer the third. into its place. You will cbferve the centre of the whiple-tree fhifts, By this contrivance, the power of the horfes is equalized, though they may be unequal in ftrength, the longer lever being given to the weaker horfe. Should the Society wifh for any farther information, it will give me pleafure to furnifl) them with it, Tam, Dear Sir, ? Very truly and fincerely, yours, EDMUND CATWRIGHT, Woburn, December 14, 1802. Charles Taylor, E{q. > Te Reference to the Engraving of the Rev. Evmunp Carvr- wricut’s Three-Furrow Plough.—Plate I]. Fig. 1, 2. Fig. 1. AB, the two wheels of the plough, the wheel B being full one-feventh in diameter larger than the wheel A. CDE, the three beams of the plough, of which C is the fhorteft and E the longeft: thefe beams are fixed in, fhe ftrong crofs | piece F, at equal diftances from each other, and braced by another crofs piece from C to E. G HI, the three cutters which anfwer the purpofe of both coulter and mould-board, each being formed together, or made of one piece of beaten iron. Each cutter is {crewed to its beam by the flanging-iron K, | ? LM ANCIENT STATE OF SCIENCE. . QT LM, the two handles of the plough, the lower extremities Defcription of of which are fixed in the two outer beams C E, and conneéted ee reared 8 _ bya crofs piece N, to make them firmer, The handle L is fame peuge Jonger than the handle M, in the fame proportion as the beam C is fhorter than the beam E. O P, two upright pieces of iron fixed in the crofs piece F, having two holes at their-fummits for the reins to pafs through which guide the horfes, S, an iron bar which flides up and down near one end of the erofs piece F, to raife or lower the wheel A, | Fig. 2. Shows a detached portion of the {trong crofs piece F, to explain the manner in which the whiple-tree fhifts (R) are fixed in front of that crofs piece; fo as to peaiate or equalize the power of the horfes, S, a bar of iron, the lower part of which forms the axis of the wheel A, the upper part flides in a groove, in the crofs piece, F, and has holes at different diftances, Jt may be re- tained at any height by an iron pin T, which paffes through the crofs piece, and one of the holes of the iron bar. The real plough is nine feet long to the extremity of the handles and each utter turns a nine-inch furrow; from centre to centre of the beams, being nine inches. VI. On the State of Science among the earlier Nations of Antiquity : and more efpecially of thofe Refearches which conftitute the Subjects of Alchemy. In a Letter from E, P. To Mr. NICHOLSON. . Rofeommon, April 1, 1804. SIR, Ir is an authenticated faét, that much of our late fcientific Reafons for acquifition, and many of thofe faéts which the experimental thinking that the modern fci=, genius of the prefent age is daily bringing io light as original ences were difcoyeries,; were well known in more ancient periods of the known to anti- world; and there is abundant reafon for fuppofing that, in che- a mifiry and metallurgy, the philofophers of thofe ages were fu- perior to thofe of the prefent day. , But Tranfmutation of metals. ‘Decompofition Of water. Alchemy. ANCIENT STATE OF SCIENCE,s But we muft mount up much higher than what are called the dark and barbarous ages of modern Europe, or even of any of thofe revolutions in the Eaft of which hiftory has tranfmitted any detailed accounts.—Science had began to decline previous to the earlieft hiftoric relation which is extant, and there ap- pears fufficient evidence that the Greeks and Egyptians, in their hieroglyphics, their allegoric devices, and in their my- thologic myfteries, which they had blindly received from their enlightened predeceffors, were recording for pofterity a feries of phyfics, of which they were ignorant, and which is now gradually unfolding. é The univerfal rage for penetrating into the fcience of ale chemy, not only indicates the {carcity and value of gold in all ages, but evinces, I think, that there has always exifted fome tradition of fuch a iranfmutation having been once effe@ted. The decompofition of water into different gafes was cer- tainly once known; and our recovery of that fublime phe- nomenon, which feems the key to the great laboratory of na- ture, bids fair to reftore to mankind the moft important faéts which have lain in obfcurity for fo many centuries. Of thefe, alchemy will probably be one; it has deeply exe cited the attention of fome excellent chemifts in this ifland, with whom I have the honour of being conneéted: of any progrefs we may hereafter make, you fhall be immediately ap- prifed; and if you, or any of your ingenious correfpondents are engaged in a fimilar courfe of experiments, we might mue tually affift, and abridge each others labours, I have the honour to be, Your fincere friend and zealous well-wifher, E. FP. P. S. A feries of experiments on this fubje€ will probably throw confiderable light on the lunar (more properly lunatic) fiones, the rational phenomena of which you have taken fo much laudable pains to elucidate, Defeription MACHINE FOR CLEARING ROADS. 99 VIll. Defeription of a Machine for Clearing great Roads from Mud. Communicated to the Society of Arts, by the Inventor Dr. JouN Wintexrsorrom, of Newbury, Berks*. | In a defcription of this machine, I fhall briefly notice the Machine for en's 7 es clearing roads five principal parts of which it is compofed; the frame, the from muds {craper, the chain, the fledge, and the pole; becaufe a very accurate model accompanies this paper, made upon the ufual {cale of one inch to a foot. The frame (fee Plate I. Fig. 1.) confifts of two pieces of timber AA, which at one extremity are formed into a pair of fhafts BB, and at the other are ftrongly united by three tranf- verfe pieces CDE. The feraper F is placed under this frame-work, in an oblique direétion, at an angle of 30°, between two of the tranf- verfe pieces C D, and confequently forms an angle of 150° with the line of draught. By this pofition of the fcraper, the machine, when ufed, actually clears itfelf from the mud as faft as it is colleéted, and removes it into a heap on one fide, after the manner of a plough. The chain G is conneéted with a piece of iron-work H, which projects from the lower end of the fcraper; for here additional power is required, as the whole body of the mud, which has been collected, muft pafs off by this extremity. Some advantage has alfo been gained by making this end of the {craper fhorter than the cther, The fledge II is conftruéted upon the upper part of the frame, that by inverting the machine it can be tranf{ported without injury to the fcraper, over the moft rough and ftony roads, or pavements, to thofe places where its ufe is par- ticularly required. The pole K, which is moveable, ferves the purpofe of a rudder, that when the machine happens to be forced by any great weight of mud, or folid body of earth, &c. from its proper direction, it can be eafily reftored to its former pofi- tion: and it may alfo be obferved, that the moderate preflure * To whom the filver medal was voted. ‘There is a model in the Society’s Repofitory. dy of 50 Machine for clearing roads from mud. MACHINE FOR CLEARING ROADS. of the hand upon the pole tends to make the machine fteady, and therefore caufes it to work ‘to more advantage. In the model, the pole is made only ten inches long, inftead of fif- teen, that it might occupy lefs {pace in the box. The plates in front of the pa and upon Ss fledge, are made of cait-iron. OPERATION. For the operation of the machine, two men and four horfes are required; one man to drive the horfes, and another to take the management of the pole and the direétion of the labour to be performed. The horfes are to be worked double, as commonly praétifed, two being employed to draw by the fhafts, and two by the chain above defcribed. But the manner of ufing the machine will be beft underftood by the following fketch. Platel. Fig. 3. The firft progrefs of the machine marked No. 1, commenc- ing from the arrow-mark, will remove the mud in a line to the right; the firft return, No. 2, will remove another part of it to the left. The fecond progrefs, No. 3, will take up what is left by No. J, befides the quantity which is upon the fpace now to be paffed over, and will remove it all to the right. The fecond return, No. 4, will operate in a fimilar manner with regard to No.2, and remove that to the left. Thus, by four lengths, more than twenty feet wide of a road can becleared; and this has been frequently performed in the prefence of feveral perfons. The number of lengths may be increafed at pleafure, according to the width of the road. In the neighbourhood of London! where there is inceffant travelling, it would be advifeable to ufe two machines at the fame time, one immediately following the other, asin No, } and 3, which will leave a fpace fufficiently wide for the largeft carriage to pafs, without difturbing the mud already fcraped up. There is one advantage in the operation of this machine worthy of being noticed, which is, that by the ufe of it the road is madé more even and fmooth, the {mall holes’ being filied up by the more folid parts of the mud; whereas, when roads are feraped in the ufual way, by hand, all the irregu- larities are increafed, and become the future depofits of water ; and it is univerfally known that thefe puddles, as they are called, are the chief caufe of the deftruétion of roads. I MACHINE FOR CLEARING ROADS, $1 It has been obferved, that ftones are fometimes forced up Machine for by the machine; but it appears to be thofe.only which pro- pari jeétin fuch a‘degree as to be dangerous to the traveller, and which require to be broken for the more effeQual mending of the road. ; I can fay nothing concerning the effeG@ of the machine upon dafty roads, having had no opportunity of trying it at that feafon of the year, When, indeed, the roads are watered, as about London, there is no doubt but a great quantity of that dirt may be removed, which, in a few hours of feorchs ing fun, would again be converted into a body of duft. If it fhould be objeéted, that the machine is too large, and that a {maller one, which might pafs over half the {pace of ground that this does, and ipl be worked by two horfes, would be better; I muft beg leave to anfwer, that, in my opinion, with a lefs one there would be much labour to little purpofe; becaufe this machine, which pafles over a {pace of about fix feet and a half, will not, in fome places, when the roads are very wet and very deep, leave more than three feet clear, the mud on each fide falling in and filling up, to a con- fiderable extent, the fpace already paffed over: it muft there- fore be obvious, that, under fimilar circumftances, the track of a fmaller one would almoft inftantly be obliterated. TESTIMONIALS. _ [Tam fo anxjous that the Society fhould have ample fatis- fa€tion on this head, that I fhould be happy if they would, before finally determining on the utility of this machine, con- defcend to make fome inquiries in this part of the country, where it has been publicly tried. . I can however mention, with fome pleafure, that feveral gentlemen, a€ting as Commiffoners of the Roads, have ho- noured me with their attendance during various experiments ; and, having witneffed the very powerful effeéts of the ma- chine, they have given it their public approbation at the laft monthly meeting, when the following entry was made in their -minute-book :— « Ata meeting of Truftees of the London and Bath roads, held at the Globe Inn, Newbury, on Monday, the 21ft of February, 1803. At this meeting were prefent, James Croft, Efq. 39 MACHINE FOR CLEARING ROADS; price Efq. Frederick Cowflad, Efq. Rev. Thomas Beft, Mr. Richard from mud, «Baily, Mr. Thomas Clark, Mr. John Baily, Mr. Jofepli Tanner, Mr. Thomas Pocock. «* Refolved, that the machine invented by Dr. Winter- bottom, for f{craping off mud from turnpike roads, will be of public utility, and fave confiderable expence of labour.” After this public teftimony in its favour, I might perhaps be excufed from producing the ceftificates of a few indi- viduals: it will; notwithftanding; be neceflary to give fome eftimate of the probable faving to be expeéted from its ufe. In all trials made previous to the 21ft of February, the machine had been worked upon no meafured extent of ground ; but the general effeéts were fuch, that feveral perfons of great experience in the management of roads, rated the daily work of one machine only as equal to the labour of fifty or feventy men: fifty being the loweft eftimate ever named. A few daysago I dire@ed fome work to be done by meafure; and I can now flate it as the opinion of. two very competent judges, that one machine will clear three miles in a day, twenty feet wide (confifting of four lengths, and making the day’s work twelve miles) which is confiderably more than 120 men can do in a day. 120 men, at 2s. per day 12 ee 6 Four horfes and two men can here be hired to work the maz chine forthe day, at - 1 5 O Difference “ g « 102 151 20 At a diftance, where carriages run principally in the centre of the road, the chief bufinefs in the management of it cone fifts in keeping the fides clear and open. One machine may therefore be occafionally employed in outfide work only; that is, may go fix miles, and return, (making twelve miles, as juft mentioned) with the faving already given, Whatever furprife thefe calculations may occafion, the Society will perhaps be fatisfied that I have not over-rated them, when I produce the refult of a fair experiment, made onthe 25th of February, in the prefence of four truftees (Frederick: Page, Efq. Francis Page, Efq. Mr. Thomas Clark, MACHINE FOR CLEARING ROADS. 33 Clark, and Mr. John Baily) and others, by which it appears, Machine for that two miles, by meafure, on the road to Reading, were Pang Feo _ cleared from mud, to the extent of 18 or 20 feet wide, by two machines, in the fpace of two hours and a half, by the watch ; and the work was judged to be equal to the labour of more than eighty men ina day. The fuceefs of this experiment was fo fatisfatory to the above-named truftees, for I was not prefent on the occafion, that they dire¢ted, without my knowledge, the remainder of our diftrict on this road, extending feven miles, to be cleared in the fame manner; and I can now declare, with fome degree of pleafure, that this was a€tually completed by two machines in one day, viz. on the following day, the 26th of February. Of this day’s work I have heard it affirmed, by an experienced furveyor, that it could not have been done in one day by 400 men. I confefs that I am myfelf unable, from the want of prac- tical knowledge on this fubjeét, to form a comparative eftimate between the work done by this machine and by hand: I have therefore fought for information from perfons of refpeétable characters, who have been furveyors, or renters of roads for “many years: and I have been aflured, as well. by thofe who were prefent at the experiments, as by others who examined the reads afterwards, that it would require fixty men a mile, to do the work in one day, which a, fingle machine will ac- complith at four lengths; and it has been already fhown, that three miles can, without difficulty, be cleared ina day: one machine will therefore do the work of one hundred and eighty men, But I have taken the average at only two thirds of this eftimate, viz. at forty men per mile inftead of fixty, being more willing that the power of the machine fhould at prefent _ be under-rated, than that the public fhould be deceived or dif- appointed concerning it. The truftees of the London and Bath roads, being defirous _ of haying thefe two machines, which had been conftruéted on my account, and under my own infpeétion, for making the experiments, I have confented to difpofe of them: and as far as I am now able to judge, the price of a Hy ae complete will be about ten guineas. Finally, I muft beg leave to advife thofe who are inclined to make a trial of this machine, to be careful whom they in- fw oi, VIIl.—May, 1804, D tend 3k Machine for clearing roads from mud. MACHINE FOR CLEARING ROADS. tend toemploy in the conftruction of it; for I can affure them, that it is not fufficient to attend only to the form of the model ; but it is abfolutely neceffary that the different parts, and ef- pecially the two braces behind, fhould be firmly put together, otherwife it will be impoffible for it to withftand the force that mutt fometimes be exerted upon it by four, or perhaps by fix horfes. The feraper may be made of beech or elm, &c. but the other parts ought to be made of ath; and I muft par- ticularly recommend thefe materials to be well feafoned ; all which circumftances were minutely attended to in the two machines which were made for me by Mr. Jofeph Mofs, of Gieenham, near Newbury. JOHN WINTERBOTTOM. Certificates from Mr. George Goddard, Greenham, near Newbury, Mr. Francis Page, Mr. Frederick Page, Mr. John Baily, and Mr. Thomas Clark, accompanied the above paper ; flating, that on the 25th of February laft, two miles had been cleared in two hours and a half, by two of Dr. Winterbottom’s machines. Reference to the Engraving of Dr. W1ntTERBOTTOM’s Ma- chine for Clearing Roads from Mud.—Plate I. Fig. 1, AA. Two pieces of afh timber, forming at one extremity a pair of fhafts, BB. CDE. Three tranfverfe braces, to fecure firmly the tim- bers above-mentioned. F, The iron plate, or front of the fcraper, fixed within the braces C D, at an angle of thirty degrees, extending on “the further fide two feet, and on the nearer fide one foot and a half beyond the timbers. G. An iron chain, one end of which is faftened to the outfide of the timber A; the other end of the chain may be moved nearer to, or further from that end of the fcraper which . depofits the mud, by means of notches in the iron muzzle H, fixed to the fcraper, and which regulates the qe of the horfes attached to the ring at G, K. The pole, or rts e, to be made fifteen feet long, which paffes through the {trong holdfafts in the braces CD. This pole aéts asa lever, as the {craper may be raifed or funk by * HYDRAULIC ENGINE. 35 by it, at pleafure. The perfon who holds it may dire€t the Machine for {eraper in its proper line, and affift it in overcoming any ob- oe oe ftacles it may meet with in its way, or in giving it additional preffure where neceffary. II, Show the two parts of the machine which form the feet, or. fledge part of the machine, on which it flides when réverfed, and which enable it to be removed from place to place, when the fcraper is not in ufe. Thefe feet are ftrongly fixed to the timbers AA, and ftrengthened by a tranfverfe brace betwixt them. _L. {s theiron chain, or back band, which lies upon the cart-faddle of the horfe in the fhafts, and which Epes the fhafts. Fig. 2. Shows, on an enlarged fcale, the iron-work, fixed on the outfide of the fhafts, to which the chain and horfe are atiached. Fig. 3. Defcribes, in a fmall extent, the track ufually made by the {craper in a large way, in four rows, commenc- ing at the arrow mark, in the track No. 1, returning after it has gone any length required by the track No. 2, proceeding _ again by the track No. 3, and forcing the mud colleéted by _ the tracks No. 1 and 3 to the right fide of the road, and, on its return by the track No. 4, depofiting the mud of the tracks No. 2 and 4 on the left of the road, as is more fully defcribed in the preceding account, and thus clearing from mud a breadth of road twenty feet wide, by four paffages of the machine. 7 IX. Defcription and Drawing of an Hydraulic Machine, with an Account of several Inventions of early Date, which have been ' fiance brought forward by later Inventors. Extracted from a ¥ Foreign Work publifhed early in the lat Century. By a Correfpondeut. To Mr. NICHOLSON. SIR, : ] HAVE lately met with a work in French, entitled Recuedl Account of the @Ouvrages curieux de Mathematique et Mecanique, ou Defcrip- AE - ‘ oi 2 Cabinet de Monf. Grollier de Serviere, in quarto, Monf, de Ser- D2 printed Vieres 86 HYDRAULIC ENGINE. printed at Lyons in 1719. The book is divides? into three parts, the firft of which contains curious engravings of delicate, Yurnerys eccentric, fwafh and rofe-work turnery, the methods of pro- ducing which are to be found in Moxon’s Mechanic Exercifes, and in other later works on that fubject. Upon this part I fhall make no other remark, than by demanding of your correfpondents, whether the oval chuck, or uigine for turns ing ovals, was unknown fo late as the period above fpecified. If Monf. de Serviere had known it, I fhould fuppofe he would have introduced ellipfes among the various figures he has ex- _ hibited, The fecond part of the work confifts of clocks or Time-pieces timepieces, more remarkable for fome fingularity in figure or ftruéture, than any improvementin the artof meafuring time; and, the third part contains models of hydraulic machines, with fome engines for military and other purpofes. Many of Hydraulic mae the hydraulic machines appear better calculated to be fhewn chines. in a model, than carried into effeét on a larger fcale, and, among the other engines, I fee nothing which, at the prefent day, would much conduce to the entertainment of your readers. I have, therefore, fent you a drawing of the hydraulic engine _exhibited in his 49th plate, and after the defcription, I will mention a few other obje€ts which have been thought of more modern invention. Hydraulicoma- In Plate IV. Fig. 2. A and B reprefent two folid pinions chine deferibed- made in wood or petal and occupying all the interior {pace Pinger of the oval box or chamber CD; in which they turn freely in an elliptical and take into each other. The chamber C D is to be well Wes and folidly made, having an openipg below at D, as in the figure, and alfo at E, where the aperture correfponds with the bore of a pipe F, applied and fixed to the fame. Every other part is well clofed and fecured. Fig. 3, Teprefents the cover or cap. This chamber is properly fixed under the water of the well, or ciftern, out of which the fupply is to be obtained, and in this fituation, the elbow or handle G, Fig. 1. PlateIV. is fixed on the fquare of the axis A. This handle is conneéted with another H, by the iron fliding piece I, which moves upon the fixed pin K, and obliges its two extremities conitantly to move alike. Wiicactier therefore the handle H is turned by the firft mover M L, the other arm G muftalfo revolve to- gether with its pinion, and by confequence the other pinion B, _ When - Se a HYDRAULIC ENGINE. 37 When the two pinions turn (fo that their upper teeth may Its action. conftantly approach each other, while the lower recede,) the water which lies between their teeth in the lower part D of the chamber, will be carried round till it arrives -at the part C, where it will be compreffed by the continual augmen- - tation of water, which is brought thither between the teeth, (or rather by the perpetual diminution of the fpace between the two uppermoft teeth that touch thechamber). So that the _ fluid will enter the pipe F, and be forced to the intended place. Thus far I have tranflated from Monf. de Serviere. The Remarks on the machine appears to be ingenious, and though liable to the “8 objeétions of wear which you very properly urged againft the {chemesof O. B. and others*, feems preferable to them in feveral refpeéts. I think it would bean improvement, to caufe the axis A : and B to drive by a conneétion of external wheel-work, inflead of depending upon their interior teeth, which require tobe well figured and fitted, and kept fo, by not loading them with preffure of one furface againft the other. It feems fcarcely neceflary to remark, that we have better methods of connec- tion for work at a diftance in our cotton gear and elfewhere, than the fliding piece I; and laftly, I would propofe it as a mathematical exercife to determine the law of the velocity of the fluid through F, when the rotation of.the machinery is uniform. Among the machines which I believe have been confidered O!d engines res as of later date, but are found in this work, are the engine is ei , mentioned in Defaguliers, for raifing water bya lofing and Lofing and gain- ” gaining bucket, and regulated by a fly; the chain pump, for oe which Cole had a patent, but which is&nown to have been _ of very ancient ufe in the Chinefe Empire; the horfe mill Adam Walker's worked by the wheels of a carriage, as lately propofed by the 2° ™"”- ingenious Adam Walker; and the gouty chair of Merlin, worked by two {mall handles conneéted with a uc of {mall wheels attached to the fore feet. Iam, Sir, with efteem, - Your obliged Reader, ri a Be , * Philof, Journal. Quarto feries. IV. 468. 38 ON PERISCOPIG SPECTACLES, 2a An Examination of Dr. Wollafton’s Experiment on his Perifcopic Spectacles. By Mr. Wiitam Jones, F. Am. P. 8. To Mr. NICHOLSON. SIR, ‘ Preliminary ob- "THe inferences that Dr. Wollafton has thought it beft to ab publifh in your laft month’s Journal, inftead of a direét reply to my refutation of his new principle of {pe@tacle glaffes, are of themfelves fufficient to convince any impartial perfon of the validity of the objeétions advanced by me in your preceding Journal; and, notwithftanding an extraordinary experiment he has therein related, as made only by himfelf, I fhould not have thought it requifite to trouble your readers again, but for the an feanted imputation that he has declared againft me, that of having by an experiment deceived myfelf. I sf Sir, I may be allowed, in contradiGtion to this, to obferve, that, after more than 20 years experience in the praétice of my pro- feffion, fuch as daily adminiftering to decayed vifion, and . — employment in the conftruétion of all kinds of optical in- firuments, I fhould not be acquainted with all the various properties of lenfes, fingly or combined, and efpecially of fo fimple and well known a form of lenfes as adopted by him, is an idea, that I am confident he will not be able to imprefs upon the minds of the public. I fuggefted no new experi- ment, nor was any one wanting; the definitive laws I ad- - duced, were contained in the works of the beft writers on optics, and were fufficient to evince the want of originality and improvement of his menifcus fhaped lens. In refpe@ to the experiment by which he attempts to inforce a proof of an advantage in his fpeétacles, its value will be known by the following account of a repetition of it. Experiment with Iam poffeffed of a pair of his perifcopic glaffes, mounted a pair of perifco- jn a fingle fleel frame, which coft 10s. 6d. The glaffes, I ertnced wit 4 muft obferve, are different to his propofed form, Having of pair of the ufual each, the inner fide, or that next to the eye folittle aeitbraied, conftructions that by any perfon but an optician, they would be called plano convexes, The focus is four inches, the fame as ufed by Dr. Wollafton in his experiment. In a fimilar mounting - | ~ with’ ‘ON PERISCOPIC SPECTACLES. 39 with double convex glaffes of the fame diameter and focus, I provided a pair of our own manufaéture, and as fold by us at 3s. 6d. Thefe two pair of {peétacles were attentively compared together, by myfelf and feveral judicious and im- partial perfons, in the manner as ftated by Dr. Wollafton of ‘his. The refult was as follows. The convex glaffes being applied as clofe as poffible to the Refult. With eyes, with the frame attached to the head, the print of a large we a ae quarto page was viewed through them, at adiftance for diftin€t pytent of dif- vifion at their centres, the letters at the diftance of about 25 tin vifion. lines, appeared quite diftiné or well defined; giving the axis “tah of the eyes a little obliquity to difcriminate more lines, an indif- tinGinefs or confufion of letters commenced, increafing to- wards the extremity of fight, and from the lateral aberration of the lenfes, the letters were tinged with the prifmatic colours. Keeping the head fixed in the fame pofition, the with the perif- perifcopic glaffes were fubflituted. The extent of diftinét copicglafes, letters without diftortion was nearly as great, but the coloured more colour. letters were evidently nearer to the centre, and more numerous than by the other glaffes. By inclining the axis of the eyes ftill more than in the former cafe, or looking extremely afquint through the glaffes, a greater extent of lines was obferved, but blended with colour and confufion. ‘The optic nerves felt a fenfible irritation, evidently from the fquinting pofition of the eyes, a refraétion of many fuperfluous rays, and the confequent increafed and unufual magnitude of the images on the retina. The pain in the eyes mentioned by Dr. Wollafton, muft have arifen only from this circumftance, and not from the one he reprefented it to be. By a trial of the old menifcus Trial of another glafs I before mentioned, which is of four inches focus, and menifcus, - correfponds with what he has a patent for, in comparifon with one of the above plano convexes, the view of letters was ftill more extended, but illegible and with much colour, and like the others towards the extremity, of no fort of ufe for the purpofes of vifion. Now all this is conformable to the laws of optics, and manifefis a property differeni to that advanced _ by Dr. Wollafton. Thefe feveral glaffes are alfo at the public fervice for in- fpeétion in our fhop in Holborn. By making the glaffes of the above perifcopic fpeétacles Concluding re- pearly planos, Dr. Wollafton’s peste) is deftroyed, and my rails, opinion EXPERIMENTS AND OBSERVATIONS ON THE > opinion evidently verified; that the nearer a menifcus ap- proaches to a plano, the more perfeét it will be, as the fpherical {urface, for the fame focus, is diminifhed, and confequently the aberration befides; admitting that there were any advantage defirable from a’ great obliquity of the axis of the eyes to thofe of the minifcus fhaped fpeétacle glaffes. I would afk, for what reafon has man his head moveable? was it not, that he fhould place his eyes direétly before the objeét to be viewed, and not fubjeét himfelf to fallacious ideas of them, by an aukward and revolutionary fquinting. From what I have advanced, I doubt not of the public decifion, (from a fair comparifon of the two kinds of fpeétacles) in favour of the eftablifhed double convex fpeétacle-glaffes, for ; “ Magna eft veritas et prevalebit.” lam, Sir, : Your refpeétful humble Servant, © W. JONES. Holborn, April 10, 1804. He XI. Experiments and Obfervations on the Change which the Air of the Atmofphere undergoes by Refpiration, particularly with Regard to the Abforpiioncf Nitrogen. Ina Letter from ALEXANDER Henverson, M.D. - pism different animals; ~° °° °' 3 Method of fee | fake a quantity of bones of adult animals, burn them to parating mage whitenefs'in-an' open fire, and reduce thein ‘to a fine powder. nefia from the bones of ani- Upon one part of this powder, after having been put into ¢ mals. convenient earthen or glafs veflel, affufe an equal quantity by weight of ‘concentrated fulphuric:acid; ftir the mixture inti- mately together, and then fuffer it to ftand for five or fix days. Having done this, dilute the mafs with at leaft ten times its bulk of water, agitate it well ‘and’ transfer it on a ftrainer. When no more fiuid pallies, diffufe the mafs again through five times its quantity of water, and ftrain again as before, and ree peat this procefs till the’ water runs taflelefs. ©The fluids thus obtained, are to be added together, and mingled with liquid ammonia, taking care the latter bein excefs. The preci- pitate which is obtained ‘confilts of phofphate of lime, phof- phate of ammonia, and phofphate of magnefia. (To feparate i" | thete Se ——————— NEW EARTHY PHOSPHATE, thefe falts, wath it in as little cold water as poffible, and boil it in a folution of potath fo long, till the odour of ammonia is no further perceptible. The potafh in this procefs decompofes the phofphates of ammonia and magnefia, leaving the latter and phofphate of lime. To feparate thefe two, let the whole be boiled in acetic acid, the magnefia will be diffolved, and the phofphate of lime remain untouched. To obtain the magnefia, let the folution of acetite of mag- nefia be carefully evaporated to drynefs, re-diffolve the falt in water, and decompofe the foluiion by carbonate of foda; the precipitate obtained is carbonate of magnefia, If it be pure carbonate of magnefia, it will be completely foluble in ful- phuric acid; if it contains lime, the folution will be cloudy, and a precipitate will gradually be depofited. Such is the method we employed for deteéting and feparat- ing the magnefia contained in the bones of animals; it is per- haps tedious, but it is eafy and certain. _ The bones of the ox examined in this manner yielded fome- thing lefs than 4; of its weight of fulphate of magnefia, which is equal to about ,, of phofphate of magnefia, or in the burnt bone to 54. The bones of the horfe and fheep afforded =z of phofphate of magnefia. Thofe of fowls and fith yielded nearly the fame quantity as thofe of the ox, The refults of a general analyfis of the bones of the ox were: ‘Dry gelatine - - - a he Phofphate of lime. - - Bio F : Carb. of lime - - - - 10 0 Phofphate of magnefia - ~~ - l. 3 100 0 The prefence of phofphate of magnefia in the bones of ani- mals, and its total abfence in thofe of man, calls upon the phy- fiologift to point out the fource whence this falt is derived in the former, and why it is not met with in the latter. That it 87 Method of fe- parating mage nefia from the bones of ani- mals. forms a conftituent part of the food of both, we have proved — elfewhere ; that phofphate of lime enters into the compofition | of wheat, barley, oats, peas, &c. Why then is it not to be found in the bones of men? The nature of the human urine, may perhaps aflift in explaining this problem, We have proved ANN that 88 NATURE OF OXIGEN, HIDROGEN, CALORIC, &c. that the urine of men contains phofphate of magnefia, and that the urine of animals is free from it. This falt is therefore ejected in man, by the kidneys; it therefore does not enter into the compofition of bones; moreover the urinary calcult of man frequently contain phofphate of ammonia and magne- fia, but no fuch falts are ever found in the ftony concretions of . the inteftinal canal, maaan bee a So ES ee ey IX. On the Nature of Oxigen, Hidrogen, Caloric, &c. as deduced JSrom Galoanic Experiments. By A CoRRESPONDENT. On the exiftence SINCE we are told that oxygen is one of the moft effential Of oxigen. fubftances in the produétion of the moft ftriking phenomena of nature; that heat and light refult from its change of com~ bination, nay, that animal life is dependant on if, it becomes a matter of very great utility to inveftigate its nature, much more to prove whether it has any exiftence. ' It is well known that this fubftance, which has now fo long and fo generally been admitted, has never yet been exhibited except in combination, and that the evidence of its exiftence im combination has never been more than prefumptive. It appears from fome late ex- periments tobe poflible to fubftitute known for unknown prin- ciples, and to relieve {cience from thofe agents which are merely hypothetical. Oxigen and bi- ‘The wires from the galvanic combination of metals produce ae *° different effeéts when placed in the fame veffelof water. One the power from Produces inflammable air, the other vital air, When the cir- re ae cuit is made by the iuman body, a fhock fimilar to an ele@trical vanic wien, one is perceived. It therefore appears that thofe powers which thus affect the human body, change water into inflam- mable and vital air. One wire always produces one air, and the other wire another air from water. Is it not therefore philofophical to refer the produétion of one of thefe airs to the power proceeding from one end of the pile and water; and the produétion of the other air to the power proceeding from the other end of the pile and water? In this experiment we are made fenfible of no other principle, power, or fubftance than the above-mentioned. Why fhould we therefore have recourfe to two hypothetical fubfiances, oxygen and hydrogen, which have NATURE OF OXIGEN, HIDROGEN, CALORIC, &e. 8S have never in any experiment been made fenfible to us? Is it not philofophical to refer phenomena to caufes which are ob- jets of our fenfes, rather than to account for them by agents which are merely hypothetical? Under certain circumftances water is converted into two Developement airs, which airs have peculiar properties; in the galvanic ex- aetna ae periment we are made acquainted with no other agent but thofe powers which are elicited by the particular arrangement of metals, and thefe powers we are made fenfible of; they produce different effeéts on various fubftances, and therefore I contend that thefe powers are different agents: for the fame powers under the fame circumftances fhould produce the fame effects. -The zinc fide of the galvanic arrangement produces vital air, whilft the copper fide produces inflammable air.— Does it not appear from this experiment that there are other caufes befides caloric that give aeriform elafticity to bodies? And do not the two powers of the pile here feem to be real principles? Each of them produces a real and decided effec on water. At all events we have not in this experiment any reafon for afferting that water isa compound body, formed of two diftinét and folid fubftances, oxygen and hydrogen. Ido not mean at prefent to inquire whether negative electricity be @ mere negation or not. We know that it is as much a caufe of repulfion as what is called pofitive eleétricity, and that in experiments of a different kind from the one we are now confi- dering. When a fubftance has in one inftance been clearly proved to be formed of certain principles, it is confiftent with philofophical accuracy to refer in all other inftances to the fame principles as the caufes of the produétion of fuch fubftance. -Inflammable air therefore is water rendered aeriform by nega- tive electricity or galvanifm; and vital air is water rendered aeriform by pofitive eleétricity or galvanifm. This is nearly the enunciation of the faét, and I contend that in this, and in . all the reafonings refpe@iing water and fire, we have no occa- fion for the two hypothetical principles, oxygen and hydrogen. In the above experiment with the pile of Volta, it appears The effe& not that it is not caloric which caufes the elaftic aeriform ftate of 44 by calories either the vital or the inflammable air, at leaft we dre not made fenfible of it. If it were caloric that proceeded from the two wires of the pile, why fhould each wire uniformly produce ' the fame air, and one different from the other? There fhould be 90 ON THE YOLK OF WOOL. be fome reafon why the folid bafe hydrogen attaches itfelf to the caloric of the one wire, and why the folid bafe oxygen is always fo ready to enter into combination with the caloric of the other wire. Compound na- —- Scheele has afferted the compound nature of the matter of turcofheate = heat, and that all inflammable bodies contain a principle of inflammability, which principle, by combining with his igne- ous air, produces the phenomena of combuftion. It does not appear that this opinion has been controverted by any decifive faét. We now know that fome principle befides caloric is neceflary in the production of one inflammable body, namely,. of inflammable air; which principle, by combining with vital origneous air, produces combuftion. ‘The re-produced water iscommon to both. Generation of I think upon a further profecution of this inquiry, it will ss appear, that fire is generated during combuftion, that it is fire alone, (that is, the principle which caufes the fenfation of heat) that caufes all the phenomena of combuftion, and that it is, as Scheele obferves, the water of his igneous air which forms the additional weight of bodies after they are burned. I know of no chemical fa& that contradiéts this explanation, in which no new fubftance that is not fenfibly difcovered is introduced. A CORRESPONDENT. X. Experiments on the Yolk of Wool, followed by [me Confiderations on the Cleanfing and Bleaching of Wool. By Cit. Vavaue- LIN.* Yolk of wool. SEVERAL philofophers have thought that the yolk of wool was a fatty matter; others from its diflolving in water could not adopt the fame opinion. Chemical analyfis alone vould decide this queftion, and this is what I propofed to myfelf in the work, the refult of which I now offer. A@tion of water Ift. Water deprives wool of much of its colour, and the upon wool. liquid acquires colour; odour and tafte. 2d. The wathings of the wool is milky like an emulfion of gum-refin, and paffes through paper with difficulty. * From the Ann, de Chimie, Fruétidor, An. XI. No. 141. 3d. In ON THE YOLK OF WOOL, - 9] 3d. In time it gives a depofition of fand, carbonate of lime, and feveral other foreign bodies; it lathers by agitation and ‘heat like a folution of foap. 4th. The water with which wool has been wahhed, filtered Aqueous folu- tion and extraét. | and evaporated, yields a brown extraét, thick like a fyrup, of. an acrid, falt, and bitter tafte: in this ftate it ftill retains its peculiar odour. 5th. Alcohol, applied to this extraét, diffolves a part which Extra expofed communicates a reddith-brown colour to it: if the alcohol be © sii feparated from this fubftance by evaporation, it affumes the form of a tranfparent, thick, and vifcous honey. The following are fome of the properties which it offered: To acids. Li. Lt Bigolves eafily in water, and its folution is {peedily coagulated by the acids, which feparate a fat fubftance from it, infoluble in water. The matter thus feparated by the acids, colleéis very flowly; its colour is yellowifh. The acids, as will be feen lower, retain a great quantity of it in folution, which gives them a reddifh brown colour. By evaporation, be Ln ois the greateft part of this fubftance, diffolved by the acids, is eee depofited in the form of a black bitumen, and falts are obtained with bafe of potafh and of lime. The greafy matter is fo ad- herent to thefe falts that they cannot be obtained in a ftate of purity and whitenefs, until after feveral calcinations and folu- tions. At the fame time that the acids precipitate this fat matter, base acidy they drive off a certain quantity of acetous acid, very dif- Nt a tinguifhable by its odour. Concentrated fulphuric acid black- ens the infpiffated yolk, and difengages fome vapours of mu- rialic acid, . 2d. Lime-water renders the folution of the yolk turbid and Lime-water, milky, but it does not form a coagulum in it as in a folution of common foap. _ $d. Cauftic alkalis or quick-lime do not demonftrate the Cauttic aikalis _ prefence of ammonia, and giiel-BaRe. 4th, Nitrate of filver produces a yellow precipitate in it, Nitrate of filver. which attaches itfelf to the fides of the veffel, like a fat /ub- flance. Great part of this precipitate is diffolved in nitric acid, + The part of the yolk which is infoluble in alcohol has ftill a The infolubie falt tafte, but lefs diftiné& than the part which is foluble in this Sa rah al re-agent. After having been thus treated with alcohol, it does Is not entirely not entirely re-difolve in water; there remains a glutinous ten inl matter, treated with alcohol. 92 Contains an al- kaline carbonate. A€tion of see agents. Yields fulphate of lime by ful-~ phuric acid ; ON THE YOLK OF WOOL. matter, of a grey colour, with which the acids produce a pretty brifk effervefcence, which fhows the prefence of an alkaline carbonate. The portion which retains its folubility in water communicates a reddifh colour and a faline tafte to this fluid ; its folution is not difturbed by the acids, as it was before having been treated by alcohol. Cauftic alkalis do not difengage any ammonia; the muriate of barites forms a very abundant depo- fition in it, the greateft part of which is foluble in water: the nitrate of filver alfo occafions a precipitate init, which diffolves partly in nitric acid. Alcohol precipitates this matter in the form of amucilage, which is depofited quickly. Nitrate of iron being mixed with the folution of this fub- ftance, formed a brown precipitate in it, and at the end of fome days, the liquor furnifhed a pretty Jarge quantity of ni- trate of potath. The yolk being decompofed by dilute fulphuric acid, and the liquor filtered, it blackened by evaporation, exhaled va- pours of fulphuric acid, and became carbonaceous, as the con- centration of the fulphuric acid took place. The refidue being afterwards wafhed with water, and the folution fuitably eva- porated, yielded cryftals of neutral fulphate of potafh, but a> good deal remained in the folution on account of the fuper- abundant acid which brought it to the ftate of an acidulous falt: by a longer evaporation, this falt cryftallizes in needles and plates of a pearly white. During the courfe of thefe fucceflive evaporations, another fpecies of falt was offered, in the form of flattened needles, of a fattiny white, and without any fenfible tafte. This falt examined with care, appeared to me tobe only ful- phate of lime; it however differed from it in fome refpes; for example, it melts much more readily by the flame of the blow-pipe into a globule, tranfparent while it is in fufion, and which becomes opaque by contraéting : it is alfo much more foluble in water, and neverthelefs does not contain the acid in excefs; as I have fatisfied myfelf. Its folution in water pre- cipitates muriate of barites and oxalate of ammonia abundantly ; one of thefe precipitates is fulphate of barites, and the other oxalate of lime. Neither lime-water nor ammonia difturb its folution.. It appears therefore that this falt is a modification of fulphate of lime, which 1s probably produced by the proportion of its elements, It may alfo be poffible that this falt ftill con- 3 tains * ON THE YOLK OF WOOL, 93 tains fome portions of fat matter, which, by decompofing the fulphate of lime, and forming a little fulphuret would facilitate the fafion, Iregret my not having had a fufficient quantity of this falt, to examine its properties more minutely. The yolk diffolved in water, filtered, and infpiffated, having Acetic acid; been diftilled with dilute fulphuric acid, furnifhed a liquor in which I eafily recognized acetic acid, by its odour, its tafte, and the properties of the falts which it formed with different bafes, particularly with lime and potafh. Thus the yolk contains acetic acid, which without doubt is combined with part of the potafh. It alfo contains muriate of potath, for, with the folution of and muriatic filver it forms an abundant precipitate, which is not entirely 34: foluble in nitric acid; and, by diftillation with fulphuric acid, it gives fenfible indications of muriatic acid, which is mixed. with the acetic acid. The yolk evaporated to drynefs, and ftrongly heated in a filver crucible, fwells, chars, and exhales fetid ammoniacal vapours; afterwards oily fumes arife which take fire, and when the greateft part of the oil is diffipated, it reddens, and enters into quiet fufion, If, at this moment, it be poured on a marble, it yields a fubftance which contraéts by cooling, of a greyifh colour, and a very cauftic alkaline tafte: if this fub- ftance be afterwards diffolved in water, there only remains an infinitely {mall quantity of carbonaceous matter, and, by eva- poration, the liquor yields a true potafh flightly carbonated. It refults from thefe experiments that the oil or greafe, Recapitulation whofe prefence in the yolk has been demonftrated by means Lingle csed of the acids, is combined in it with potafh, in the ftate of a true animal foap; that, befides, there is a portion Of carbonate of potafh in excefs, fince the acids produce a pretty brifk frothy effervefcence in the concentrated folution of the yolk. Inad- ' dition to the fubftances which I have juft mentioned, the yolk contains a certain quantity of animal matter; for, by diftilla- tion, it gives very fenfible traces of ammoniac, and an oil whofe fetid odour refembles thofe furnifhed by animal matters. The yolk is therefore formed, 1/2, Of a foap with a bafe of potafh, which makes the greateft part; 2d, Of a fmall quan- tity of carbonate of potafh; 3d, Of a perceptible quantity of acetate of potath; 4th, Of lime, whofe ftate of combination Tam O+ ON THE YOLK OF WOOL. I am unacquainted with; 5th, Of an atom of muriate of pot- afh; 6th, finally, Of an animal matter to which I attribute the peculiar odour of the yolk. which are not I am of opinion that all thefe matters are effential to the acoldentale nature of the yolk, and are not found in it by accident; for I have conftantly found them in a great number of famples, as well of Spanifl, wool as of French, I do not here fpeak of the other matters, infoluble in water, which are alfo met with in wool, fuch as the carbonate of lime, fand, and filth of every fort, thefe being evidently acci- dental. Are they the It remained now to enquire if all the matters in the yolk eee were the produét of cutaneous tranfpiration, accumulated and ration ? thickened in the wool, or if they were taken up in the folds and other places in which the fheep lie. It is very certain that all the elements fit for the formation of the matters con- tamed in the yolk, are found in the excrements of thefe ani- mals, and in the vegetables which ferve them for litter. Ne- verthelefs, I could not believe that all of it was the effeét of dung; on the contrary, I am of opinion that the humour of the tranfpiration is the principal fource of it. J The analyfis of the dung offers nothing certain in this refpeét, becaufe the matters found in it may have been depofited there by the theep themfelves. In what ftate are But admitting that the principles of the yolk arife from the SS bY cutaneous tranfpiration, which is very probable, are thefe matters emitted by the body of the animal in this ftate, and do ~ they not experience fome change while they remain in the wool? This is a queftion on which it is difficult to decide po- fitively ; we can only prefume that changes are produced in it, as in all very complex fubftances deprived of motion, of which, in the prefent cafe, we neither know the caufe nor the manner. . Wahhing the The yolk, as we have feen above, being a true foap; fo- tc th Nag luble in water and alcohol, it would feem that nothing better enough to cleanfe Can be done for {cowering the wool than to wath them in runs it. ning water. But I fhould obferve that there is a {mall quan- tity of fat matter in the wool, which is not in combination with the alkali, and which, remaining attached to the wool, keeps it a little glutinous (poigeur), natwithftanding the moft careful wafhing. . But ON THE YOLK OF WOOL, 95 . But if the wool be put into buckets, and only as much water ‘as will moiften it poured in, and if it be fuffered to remain fome time in this bath, prefling it often, it {cours much better, and becomes much whiter afterwards, by wathing in running water. The -fcourers have a cuftem of macerating the wool in pu- Putrid urine trefied urine, and it is generally believed that it is the ammo- Seats feou nia which is developed that effects the fcouring ; but I have ing. fome reafon to think that this alkaliis of no value, This effet is rather owing to the yolk itfelf, or to fome other principle of the urine, to the urée, for example. The following are the grounds of my opinion in this refpeét; I put wool wathed in running water into a mixture of fal ammonia and common pot- afh; the mixture had a {trong {mell of ammonia, and never- thelefs the wool was in no refpeé cleanfed, becaufe this alkali does not form, or at leaft with great difficulty, a faponaceous combination with the greafy matter of wool. From thefe ob- fervations, therefore, I believe putrid urine to be nearly ufe- _lefs in the {couring of wool, at leaft as far as refpeéts its am- monia. Though the utility of putrified urine be in fome degree doubt- Fieth urine ful, it is, on the contrary, very certain that fre(h urine would be rate oe greatly i injurious to the propofed objeét, for the foap cantained wn the yoik would inconteftibly experience a decompotition by _ the acid of the urine, which would precipitate the greafe on the wool. | I fufpeet that the fame effect would take place from walhing As would water the wool in water containing earthy falts, which are known Containing to decompofe alkaline foaps. For which reafon it is always ucla prudent to employ ihe pureft water which can be procured for this purpote. This is not the cafe with foap-fuds, which accomplifh the Soap-fuds the _ feouring of weol perfeGily, at the fame time giving it more heft menftruum, whitenels. It, therefore, after having wathed the wool in - running water till it lofes no more, it be fuffered to macerate for a few hours in only one twentieth of its weight of foap dif folved in a fuflicient quantity of warm water, fqueezing it ‘often, it will be entirely purged gf the fmall portion of greafe which | fiill adhered to it, and will then have a fofinefs and degree of clearnefs which it could net have had without this @peration. zt, The ° 96 ON THE YOLK OF WOOL. The yolk exer- ' The yolk itfelf, when a little concentrated, as [ have already cifes an action mentioned, has an efficacious ation on the portion of greafe wah ee ag which is not in a faponaceous fiate; for I have found that, in putting to the wool only the quantity of water neceffary to cover it, it fcours better, particularly with a little heat, Danger of conti- than when it is wafhed in running water. But I alfo found ai 8 a ie that, when wool has remained too long im its own yolk, it ufing trong —s fells, fplits, and lofes its ftrength: this effeét alfo takes place foap fads. with foap-fuds which are too ftrong. ; Since the folution of the yolk occafions this {welling and fplit- ting of the wool, is it not poffible that this accident may hap- pen on the fheep’s back, particularly in hot, moift feafons, or when they are fhut up in folds in which the litter is not often The acrimony of enough renewed? Nor would it be impoffible that the acri- the yolk pto- =~ mony of the yolk fhould occafion an irritation in their fkins, bably hurtful to ) the living ani- and, by that means, be the caufe of fome of the diforders to mal. which this organ is liable in thefe animals, which muft princi- pally happen in hot and damp weather : fortunately, in thefe feafons, they are from time to time expofed to rains which wath them, and carry off at leaft a portion of this matter. On Wahhing recom- this fubjeét [ cordially agree with thofe who think that wath- meee ing fheep in hot and dry weather, would be ufeful to their health and the quality of their wool. Lofs of weight § The lofs experienced by fcouring wool is very variable; by feouring. the greateft I met with was 45 per cent. arid the leaft 35; it it is true, thofe which I wathed were very dry. This lofs is not wholly owing to the yolk; the humidity, the earth, and . the filth of every fpecies, alfo contribute to it. Bleaching of I have made fome attempts to bleach feoured wool, but I fcoured woole confefs that they have not been carried fo far as they ought to have been. I have remarked, generally, that thofe which had been wafhed with foap-fuds whitened better, by every method, than thofe which had not. Sulphureous acid diffolved | in water whitened it pretty well, but it did not deftroy the yellow colour which the wool, growing in the groin and under the fore-legs of the fheep, had contra@ed. In liquid fulphu- reous acid the wool acquires the property of crackling between the fingers like brimftoned filk, and, at the fame time, con- traéts a very powerful fetid {mell, which is not diffipated in a long time. I did GALVANIC DEFLAGRATIONS, OF I did not try the vapour of burning fulphur, but all the world knows that it whitens wool well, and that the woollen manufacturers ufe it to give the finifhing degree of whitenefs to their goods. Of all the methods which I tried, I found none better for bleaching the wool, than expofing it, on the grafs, to the dew and the fun, after being well fcoured with weak foap-fuds; the yellow fpots of that from the groin, how- ever, were not entirely deftroyed; they had only diminifhed in intenfity. ‘ ee XI, Copy of a Letter from Mr. Curusertson to Dr. PEARSON, communicating an important and curious diftingurfhing Pro- perty between the Galvanic and Ele@ric Fluids. Communicated by Dr. Pearson, To Dr. PEARSON: Dear Sir, I THINK it right to inform you, that yefterday evening I Galvanic defiae refumed the experiments with the galvanic batteries; the re- 8t@tions. - fult was— - 1, Charcoal was deflagrated and ignited for about one inch in length. 2. Iron wire ;'; inch diameter, was melted into a ball J, inch diameter. 3. Platina wire ;2,5 inch diameter, was melted into a ball z5 inch diameter, 4, Brafs wire ;3; inch diameter, £ inch in length was ig- nited. _ 5. Ditto 3, inch diameter, was red-hot at the extremity. 6. Iron wire ~25 inch diameter, was red-hot for 16 inches in length. _ 4. Ditto 12 inches, deflagrated and melted into a ball. -. §, Ditto fix inches in length, were deflagrated. 9. Ditto 8 inches in length, were ignited. Two troughs, each trough containing 30 pair of plates fix inches fquare, were ufed for the firft feven experiments, and one of thefe troughs only for the two laft experiments, - Vou. VIIL—Junez, 1804, H The 98 Galvanic defla- grations. Paper inflamed iM nitrous gase PAPER INFLAMED IN NITROUS GAS. The four laft experiments prove, I think, that double quan- tities of galvanic fluid only burn double lengths of wire, and not the fquare, as eleétrical difcharges do *. Iam, with the greateft refpeét, Sir, Your very humble fervant, JOHN CUTHBERTSON, Poland-Street, Soho, ~ March 27, 1804. “Xa. Letter from a Correfpondent, containing an Obfervation of the Spontaneous Inflammation of Paper in Nitric Acid Gas. To Mr. NICHOLSON. Dear Sir, London, May 22, 1804. Tuat feveral different inflammable bodies, while in a ftate of inflammation or of ignition, burn with an enlarged flame, and continue ignited when immerfed in nitric acid gas, is, I fuppofe, commonly known ; but that paper itfelf would take fire. and flame moft beautifully in this gas, and at nota very elevated temperature, has not, that I recolleét, been already obferved. By the following accidental.circumftance this phe- nomenon was feen this morning in the public le€ture-room, while reading on the fubje€t of nitrous acid, In putting to- gether the different parts of the Wolfe’s apparatus, having ready only a bent tube much {maller than the lateral aperture of the globe condenfing receiver, I filled up that aperture, partly.with a piece of writing paper which projeéted into the receiver, and partly with almond pafte. Soon after the acid had begun to diftil, and while the apparatus was filled with * It is not faid whether the two troughs were ufed collaterally or longitudinally. Eleétrical jars may be confidered as being al- ways combined in the former mode. This fubje&t feems to require comparifon with the faéts given in Mr. Wilkinfon’s letter in our Journal, Vol. VII, p. 207; but the communication came too late for me to offer any remarks upon its W. Ne 4 reddifh JIBS ON A NEW CONSTRUCTION. 99 reddifh coloured nitrous acid gas, I was furprized by the burfting forth of flame from the paper, which was confumed by it in lefs than a minute, without cracking, as I expefted, the receiver, I think it unneceflary to make any comments, or give the rationale of this fact. Always your’s faithfully, AMICUS. ~ XIII. Defeription of a Jib on anew Conftru&ion; by Mr. J. BRaMaHy Engineer. Communicated by the Inventor. Jigs of the ufual conftruétion turn on two folid ee. Berean of & The rope by which the goods are raifed, paffes over the - a ae, upper gudgeon, and is confined between two fmall vertical : rollers, in order that it may conftantly lead fair with the pulley or fheave at the extremity of the jib. According to this con firuction, whenever the crane turns round its axis, the rope is bended fo as to form an angle more or lefs acute, which caufes a great increafe of fri€tion, and produces a continual effort to bring the arm of the jib into a parallel pofition to the inner part of the rope. Thefe inconveniences may appear to be trifling on paper, but. in a@tual practice they are of no fmall importance, for they neceffarily imply a much greater exertion of power in raifing goods, and the application of a conftant force to keep the jib in the pofition that may be requifite ; while the partial ftrefs which is exerted on only a few ftrands of the rope, when bended into an acute angles infallibly deftroys it in a very fhort time. The fimple conftruétion exhibited in Plate V. obviates all thefe defeéts, and at the fame time poffefles the very defirable property of permitting the jib of what is termed a-campshut or landing crane, wholly to revolve round its axis, and to land _ goods at any point of the circle defcribed by the arm of the jib. It confifts in perforating the axis or pillar of the crane, and in conduéting the rope through this perforation by means of _an additional pully fixed on the top of the arm of the jib. \ H 2 The 4 100 ON THE FASCINATING FACULTY Defcriptionof a. ‘The nature of the contrivance cannot fail to be fufficiently jibonanew —_ynderftood by an infpeétion of the figures; the one of which a _reprefents a jib attached to the wall of a warehoufe, the other a campfhut or landing crane fixed on the edge of the wharf. ‘Each of thefe jibs turns on a perforated axis or pillar. The rope proceeds from the goods which are hoifted, through a pully fixed as ufual at the extremity of the jib; it then paffes over another pully fixed at the oppofite extremity of the jib, and is, by this pully conduéted through the perforated axis or pillar to a third pulley; whence it is immediately direéted to the crane by which the weight is elevated. It is almoft unneceffary to ftate that the lower axis is ufually fixed in an oil box, and that friétion rollers are applied to the axis wherever the circumftances may render it neceflary. The importance of this improvement, in an article of fuch extenfive ufe, muft be evident even to thofe who are the leaft acquainted with the fubjeét. Mechanics who are aware that fimplicity of conftru€tion and certainty of effect are among the moft valuable chara@ters to be fought in engines, will moft probably obferve this crane with pleafure; and the ad- vantages to the community at large muft be meafured by the convenience and faving of labour it-is calculated to afford. — XIV. A Memoir concerning the Fafcinating Faculty which has been af= | cribed to the Rattle-Snake, and other American Serpents, By BeNJAMIN SmiITH Barton, M.D. From the Armerican _ Tranfadiions, Vol. IV. (Concluded from Pape 62.) Other fnakes SECONDLY. It is a fat well known in this country, that aarp a the the rattle-f{nake is not the only kind of ferpent that is faid to which is not De Endued with the faculty of fafcinating birds, f{quirrels, and poifonous) are other animals. A\s far as my inquiries have extended, it does faidto chums not appear to me that, in general, the ratile-fnake is thought : to have fo large a portion of this faculty as fome other fpecies — of ferpents. Of this, at leaft, I amcertain, that perfons re= | fiding in our country-fituations tell us many wonderful tales of - the bewitching eyes of ba black-fnake, the coluber conftri€tor — of ‘ ASCRIBED TO THE RATTLE-SNAKE, Jol of Linnzus, as they do of the boiquira, or rattle-fnake. Now let it be fuppofed, for a minute, that the poifon of this latter ferpent, when thrown into the body of a bird, a fquirrel, 8&c. is capable of producing, in thefe animals, thofe piteous cries, _ thofe fingular movements, thofe tremulous fears, which are mentioned by Kalm, by de la Cépéde, and by other writers,— in what manner are we to account for the fimilar cries, move- ments, and fears, in thofe birds which are frequently feen under the fafcinating influence of the black-fnake? For we Americans all know, that the bite of the black-{nake is perfeétly innoxious, This, indeed, is alfo the cafe with the greater number of the fpecies of ferpents that have, hitherto, been difcovered in the extenfive country of the United States. And yet almoft every fpeties of ferpents is fuppofed to be endued with the power of fafcinating fuch animals as it oc- cafionally devours. Thefe faéts, and this mode of reafoning, certainly involve, - can aad in fome difficulty, Mr. de la Cépéde, and thofe writers who fone aati efpoufe his opinion, which I have examined, under the firft fluence is un- head of my objeétions. An attempt is made to account for rt the imaginary fafcinating faculty of the ferpent from the power- ful influence of a fubtile poifon. But, upon inquiry, it is found, that the power of bewitching different animals is not an exclufive gift of thofe ferpents which nature has provided with envenomed fangs: it isa gift which as extenfively be- longs to that more numerous tribe of our ferpents, whofe bite is innocent, and whofe creeping motion is their only poifon *. Thefe * Jf there is any impropriety in this mode of expreffion, the im- propriety has its fource in my feelings, with refpeét to the ferpents. Perhaps, no man experiences the force and the miferies of this pre- judice in a greater degree than I do. It is the only prejudice which, I think, I have not ftrength to fubdue. As the natural hiftory of the Serpents is a very curious and interefting part of the fcience of zoology ; as the United-States afford an ample opportunity for the farther improvement of the hiftory of thefe animals, and as I have, for a long time, been anxious to devote a portion of my leifure time to an inveftigation of their phyfiology, in particular, I cannot . but exceedingly regret my weaknefs and timidity, in this refpeét. I had meditated a feries of experiments upon the refpiration, the digeftion, and the generation of the ferpents of Pennfylvania. But, » 1 want the fortitude which it is neceflary to poflefs in entering on the 102 -@N THE FASCINATING FACULTY Thefe objeétions will, I am perfuaded, be fufficient to convince every unprejudiced reader, that the fyftem of ex- planation offered by Mr. de la Cépéde is unfounded in facts ; and, confequently, that the problem ay remains to be folved, in another way. Profeffor Blue © Among the number of ingenious men who have amufed re en themfelves with fpeculations on the fubjeét of this memoir, afcribesit toa and who, rejecting the commonly received notion of the moralcaufee = eyiftence of a fafcinating power in the rattle-fnake, have attempted to explain the phenomenon upon other principles, it is with pleafure I recognize the refpeétable Profeflor Blu- menbach, of Gottingen. This gentleman, in a late publica- tion, fpeaking of the rattle-fnake, makes a few remarks on the fafcinating faculty which has been afcribed to this reptile. Thefe remarks I fhall tranflate at length, ) « That fquirrels, {mall birds, &c.” fays he, “ voluntarily fall from trees into the jaws of the rattle-{nake, lying under them, is certainly founded in faéts:. nor is this much to_ be wondered at, as fimilar phenomena have been obferved in other fpecies Toetes Gepete of ferpents, and even in toads, hawks, and in cats, all of have the power Which, to appearance, can under particular circumftances, meeps bY entice other fmall animals, by mere ftedfaft looks. Here the ; rattles of this fnake (the rattle-fnake) are of peculiar fervice ; for their hiffing noife caufes the {quirrels, whether impelled by a kind of curiofity, mifunderftanding, or dreadful fear, to follow it, as it would feem, of their own accord. At leaft,” continues Mr. Blumenbach, “7 know from well-informed eye witneffles, that it is one of the common praétices among the younger favages to hide themfelves in the woods, and by counterfeiting the ‘hiffing of the rattle-fnake to allure and catch the {quirrels.”*. the tak. Inftead of flowly and cautioufly diffefting and examining their ftruéture and their functions, with that attention which the fubies merits, I am more difpofed, at prefent, to obey the in- *puniGtion of the Mantuan poet, in the following beautiful lines : ———Cape faxa manu: cape robora, paftor, ‘Tollentemque minas et fibila colla tumentem Dijice: jamque fuga tumidum caput abdidit alte, Cum medii nexus, exftremaque agmina caude Solvuntur, tardofque trahit fnus ultimus orbes, GEorG. Lib. iii. 420—494, * Handbuch der Naturgefchichte, P, 253, Goettingen: 1791. | } I do se ASCRIBED TO THE RATTLE*SNAKE. 103 I do not intend to take up much time in examining the fore- going explanation. I fhall offer my objections to it, in as concife a manner as I can. Firft. The faculty of fafcinating is by no means pecu- Examinston of liar to the rattle-fnake, but is attributed as extenfively to the oa black-fnake, and other ferpents, which are not furnifhed with which are con- the crepitaculum, or fet of bells*, by which this ferpent in fuppofed to be enabled to ring for its prey, when it wants it. Secondly. Some perfons, who have feen the rattle-fnake in the fuppofed aét of charming, affure me that the reptile did not fhake its rattles, but kept them fill. It is true, that Mr. Vofmier’s rattle-fnake, already mentioned, pio fhook its rattles. _ Thirdly. With regard to the praétice of the young favages, Fatts and ob- fpoken of by Mr. Blumenbach, I know nothing. I have in- ou sani quired of Indians, and of perfons who have refided for a powasr of fafci- confiderable time, among the Indians, and they appear to be Scone . as ignorant of the circumftance as I am myfelf. I am in- clined to think that Mr. Blumenbach has been impofed upon; or, perhaps, the following circumftance may have given rife to the ftory.. The young Indians put arrows, acrofs, in their mouths, and by the quivering motion of their lips upon the atrows, imitate the noife of young birds, thus bringing the old ones fo near to them, that they can be readily fhot at. In like manner, the Lanius Excubitor, or great fhrike, hiding itfelf in a thicket, and imitating the cry of a young bird, often fucceeds in feizing the old ones, which have been folicited, by the counterfeited noife, to the affiftance of their young. Ever fince I have been accuftomed to contemplate the. objeéts of nature with a degree of minute attention, I have ‘confidered the whole ftory of the enchanting faculty of the rattle-fnake, and of other ferpents, as deftitute of a folid foundation, I have attentively liftened to many ftories, which have been related to me as proofs of the doétrine, by men whofe veracity I could not fufpe@t. But there is a ftubborn incredulity often attached to certain minds, In me it was firong. The mere force.of argument never compelled me to believe. I always fufpeéied, that there was fome deficiency in the extent of obfervation, and the refult of not a little attention. to the fubje& has taught me, that there is but one * Serpent a fonnette is the French name for the rattle-fnake. wonder 104 Faéts and ohe fervations re- {pecting the power of fafcie nation afcribed te {nakes. ON THE FASCINATING FACULTY © wonder in the bufinefs ; the wonder that the ftory fhould ever have been believed by a man of underftanding, and of obfervation. In conduéting my inquiries into this curious fubjeét, I thought it would be proper, and even neceflary, previoufly to my forming a decided opinion, to afcertain the two follow- ing points, viz. firft; what {pecies of birds are moft frequently obferved to be enchanted by the ferpents? and, fecondly, at what feafon of the year has any particular fpecies been moft commonly feen under this wonderful influence? I was in- duced to believe that the folution of thefe two queftions would ferve as a clue to the inveftigation of what has been long con- fidered as one of the moft myfterious operations in nature. I am perfuaded that I have not been miftaken. Poffibly, the credulous may not think as I do. It is a curious circumftance in the hiftory of birds, that almoft every fpecies, in the fame country at leaft, has an almoft uniform and determinate method of building its neft, whether we confider the form of the neft, the materials of which it is conftruéted, or the place in which it is fixed *. Some obfervations on this fubje@ are neceffarily conneéted with the point under inveftigation, in this memoir ;—indeed, they are involved in the queftion concerning the {pecies of birds which have moft generally been obferved to be enchanted by the rattle-{nake, &c. Some birds build their nefts on the fummits of the loftieft . trees; others fulpend them, in a pendulous manner, at the extremity of a branch, or even on a leaf+, whilft others build them * I do not mean, by this obfervation, to affert, that birds are neceflarily impelled to conftrué their nefts of the fame materials, or to place them in the fame fituations; yet fuch is the language of fome writers on natural hiftory, and on morals, who talk of the S¢ determinate inftinét” of animals, and who think it impoffible that ‘* animals of the fame fpecies fhould any where differ.” ** The groufe in America, we are told, perch upon trees ; the hare bur- rows in the ground; and we have, in thefe inftances, fufficient reafon to deny that the fpecies of either is the fame with thofe of a like denomination, with which we are acquainted, in Europe.” Thefe are the words of the celebrated author. See Dr. A. Fergu- fon’s Principles of Moral and Political Science, vol. i. p. 59 & 60. quarto edition. + See a very interefting account of the Motacilla futoria, or Taylor- ASCRIBED TO THE RATTLE-SNAKE. 105 them on the lowey branches, among buthes, and in the hollows Faéts and ob- of decayed, and other trees. Many fpecies, again, are content fre cine ae with the ground, laying their eggs, and hatching them, in power of fafci- the cavity of a ftone, an excavation from the earth, among osha ge the grafs of fields and meadows, or in fields of wheat, rye, and other grains. -Thus, to confine myfelf to our own country, the eagle, the vulture, the hawk, and other birds of this extenfive family, make choice of the loftieft oaks, and other trees of our forefts; the baltimore-oriole *, commonly called, in Pennfylvania, the hanging bird, fufpends a beautiful neft to the extremity of a branch of the Liriodendron +, or fome other tree; the migrating thrufh{, called robin, is content with the lower branches; the red thrufli§, the cat-bird ||, the red-winged oriole, called the {wamp-black-bird 1, and many others build in the low bufhes; the wood-peckers**, the blue motacilla (blue-bird) ++, the torchepot ¢}, and others, build in the hollows of trees, the chattering plover §§, and the whippoor-will ||j, take advantage of a hollow place in the ground, or in a ftone, which the great lark ¢q], the marfh- wren ***, &c. place their nefts in the grafs; and, laftly, the partridge +++ builds in the corn-fields. Of all thefe birds, and of a great many others, thofe which | build their nefts upon the ground, omsthe lower branches of _ irees, and on low bufhes (efpecially on the fides of rivers, creeks, and other waters, that are frequented by different kinds of ferpents), have moft frequently been obferved to be under the enchanting faculty of the rattle-fnake, &c. Indeed, the bewitching fpirit of thefe ferpents feems to be almoft entirely limited to thefe kinds of birds. Hence, we fo fre- quently hear tales of the fafcination of our cat-bird, which builds its neft in the low bufles, on the fides of creeks, and other waters, the moft ufual haunts of the black-fnake, and Taylor-bird, by my learned friend Mr. Pennant, in his Indian Zoology, pages 44, 45 & 46. * Oriolus Baltimore. + Liriodendron tulipifera. ¢ Turdus migratorius. § Turdus rufus. Mufcicapa carolinenfis. @ Oriolus phoeniceus. #* Pici ++ Motacilla Sialis. Tt Sitta. §§ Charadrius vociferus. {I\]| Caprimulgus. qq Alauda magna. *** Motacilla Troglodytes? +7} Tetrao virginianus. other 106 ON THE FASCINATING FACULTY Faéts andob- Other ferpents. Hence, too;.upon opening the ftomachs of Eger rie fome of our ferpents, if we often find that they contain birds, rea it is almoft entirely thofe birds which build in the manner I nation afcribed have juft mentioned. to {nakess This faét I had long remarked. It had made fome im- preflion upon, my mind before I had turned my attention to the fubjeét of this memoir. Lately, when 1 came to take a view of the fubjeGt, the fat appeared to me to be of fome — confequence. I thal! now avail myfelf of it. The rattle-fnake feldom, if ever, climbs up trees*. He is * Some refpectable writers affert, that the rattle-fnake does climb trees, and that it does it with eafe. Mr. de la Cépéde is of this opinion. After telling us that this reptile lives upon worms, frogs, and hares, this naturalift proceeds: ¢ il fait auffi fa proie d’oifeaux & décureuils; car i] monte avec facilité fur les arbres, & s’y lance avec vivacité de branche en branche, ainfi que fur les pointes des rochers qu’il habite, & ce n’eft que dans Ja plaine qu’il court avec difficulté, & qu’il eft plus aisé d’eviter fa pourfuite.” Hiffoire Naturelle des Serpens. p. 409. At the conclufion of his account of the boiquira, or crotalus horridus, the eloquent author has run into the fame error, in the following beautiful, though rather poetical, apoftrophe. ‘* Tranquilles habitans de nos contrées tempérées, gue nous fommes plus heureux, loin de ces plages ou la chaleur & Vhumidité regnent avec tant de force! Nous ne voyons point un Serpent funefte infecter l'eau au milieu de laquelle il nage avec fa- cilité; les arbres dont 1] parcourt les rameaux avec vitefle; la terre dont il peuple les cavernes 3 les bois folitaires, ot il exerce le méme empire que le tigre dans fes déferts bralans, dont l’obfcurité livre plus firement fa proie 4 fa morfure. Ne regrettons pas les beautés naturelles de -ces climats plus chauds que le notre, leurs arbres plus touffus, leurs feuillages plus agréables, leurs fleurs plus fnaves, plus belles: ces fleurs, ces feuillages, ces arbres cachent Ja demeure du Serpent a fonnette.” Hiftoire Naturelle des Serpens. p- 419 & 420. IT have been at fome pains to difcover whether the rattle-fnake does climb up trees. The refult of my inquiries is that it does not. Although I have had opportunities of feeing great numbers of rattle-fnakes in the weftern parts of Pennfylvania, &c. particularly in the vicinity of the river Ohio, I never faw one of them.except on the ground. The black-fnake I have often feen upon trees. I ought not, however, to conceal that in the fummer of the Jaft year, a Choktah-Indian told me, that the'rattle-fnake does climb trees and bufhes, to a _fmall height. He faid, that he had once feen one of thefe {nakes upona reed. I am not very willing ASCRIBED TO THE RATTLE-SNAKE. 107 is frequently, however, found about their roots, efpecially pe ob- : . . ° . * . ervations re= in wet fituations. It is faid that this reptile is often feen, {pe€ting the curled round a tree, darting terrible glances at a fquirrel, power of fafci- which after fome time is fo much influenced by thefe glances, ya ie or by fome fubtile emanation from the body of the ferpent, that the poor animal falls into the jaws of itsenemy. This ftory is, I believe, deftitute of foundation, though it is related by the good Cotton Mather*. The rattle-fnake is, indeed, fometimes feen at the root of a tree, upon the lower branches of which, at the height of a few feet from the ground, a bird or fquirrel has been feen exhibiting fymptoms of fear and diftrefs, Is this a matter of any wonder? Nature has taught different animals what animals are their enemies; and al- though, as will be afterwards fhewn, the principal food of the rattle-{nake is the great frog, yet as he occafionally devours birds and fquirrels, to thefe animals he nuft neceflarily be an object of fear. When the reptile, therefore, lies at the foot of atree, the bird or the fquirrel will feel itfelf uneafy. That it will fometimes run towards the ferpent, then retire, and return again, I will not deny. But that it is irrefiftibly drawn into the jaws of the ferpent, I do deny: becaufe it is very frequently feen to drive the ferpent from its hold ; becaufe the bird or fquirrel often returns, in a few minutes, to their willing to deny this Indian’s ftory: yet it is oppofed to every in- formation I have been able to procure from perfons well acquainted _ with the reptile of which I am fpeaking. However, it is not im- poffible that where trees and bufhes grow very clofe together, the fnake may climb them to a very fmall height. Mott fpecies of fer- pents move in a fpiral manner: the rattle-fnake moves ftrait on ; and this is the reafon why he cannot climb trees. In the quotation which I have made from Mr. de la Cépéde, another miftake is in- volved. He fpeaks of the agility with which the rattle-fnake moves. This is not, however, merely the miftake of Mr. de la Cépéde. We find it in Pifo. Speaking of this reptile, our author fays: *€ Tn triviis juxta ac deviis locis cernitur, tam celeriter proreptans ut volare videatur, idque velocius per loca faxofa, quam terreftria.” De Indie uitriufque re naturali et medica. p. 274. Now the truth is that the rattle-{nake is one of the moft fluggifh of all our ferpents. Linnzus was well informed, when he afferted that Providence had given ‘* the Crotalus a very flow motion.” See Reflections, &c. quoted p. 84 of this memoir. * Philofophical Tranfa&tions of the Royal Society, No. 339. habitations 108 Faéts and ob- fervations re~ {peting the power of fafci- pagon afcribed to fnakes. ON THE FASCINATING FACULTY habitations. Sometimes the bird or fquirrel, in attempting to drive away the fnake, approach too near to their enemy, and are bitten, or immediately devoured. But, from what will afterwards be faid, it will appear that thefe inflances are not fo common as is generally imagined. My inquiries: concerning the feafon of the year, at which any particular {pecies of birds has been feen under the fafcinat- ing power of a ferpent, afforded me ftill more fatisfaQion. In almoft every inftance, I found that the fuppofed fafcinating faculty of the ferpent was exerted upon the birds at the particular feafon of their laying their eggs, of their hatching, or of their rearing their young, {till tender, and defencelefs. I now began to fufpe&, that the cries and fears of birds fuppofed to be fafcinated originated in an endeavour to protec their neft or young. My inquiries have convinced me that this is the cafe. I have already obferved, that the rattle. fie does not climb up trees. But the black-fnake and fome other fpecies of the genus coluber do. When impelled by hunger, and in- capable of fatisfying it by the capture of animals on the ground, they begin to glide up trees or bufhes, upon which a bird has its neft.. The bird isnot ignorant of the ferpent’s objet. She leaves her neft, whether it contains eggs or young ones, and endeavours to oppofe the reptile’s progrefs. In doing this, fhe is a€tuated by the ftrength of her inftinétive attachment to her eggs, or of affeétion to her young. Her cry is me- lancholy, her motions are tremulous, She expofes herfelf to the moft imminent danger. Sometimes, fhe approaches fo — near the reptile that he feizes her as his prey. But this is far from being univerfally the cafe. Often, fhe compels the ferpent to leave the tree, and then returns to her neft *. * Horace, though he has not, like his contemporary, Virgil, given any great proofs of his knowledge in natural hiftory, appears to have known, full well, the anxiety of birds for the prefervation of their young : “© Ut aflidens implumibus pullis avis ‘¢ Serpentium allapfus timet.”* Epop. 1. The author of thefe two fine lines, had he lived in iene the land of fafcination, would, I am inclined to think, have dif- believed, the whole ftory. They would have been a clue to light’ and truth on this fubject. ; It ASCRIBED TO THE RATTLE«SNAKE, 109 It is a well known fat, that among fome fpecies of birds, ee: and ob- the female, at a certain period, is accuftomed to compel the pai a gy young ones to leave the neft; ‘that is, when the young have power of i acquired fo much ftrength that they are no longer entitled to oe F all her care. But they ftill claim fome of her care. Their _ flights are awkward, and foon broken by fatigue. They fall to the ground, where they are frequently expofed to the attacks of the ferpent, which attempts to devour them. In this fituation of affairs; the mother will place herfelf upon a branch of a tree, or bufh, in the vicinity of the ferpent. She will dart upon the ferpent, in order to prevent the deftruétion of her young: but fear, the inftin& of felf-prefervation, will compel her to retire. She leaves the ferpent, however, but for a fhort time, and then returns again. Oftentimes, fhe prevents the deftruétion of her young, attacking the fnake, with her wing, her beak, or her claws. Should the reptile fucceed in capturing the young, the mother is expofed to lefs danger. * For, whilft engaged in {wallowing them, he has neither inclination nor power to feize upon the old one. But ihe appetite of the ferpent-tribe is great: the capacity of their ftomachs is not lefs fo. The danger of the mother is at hand, when the young are devoured. The fnake feizes upon her ; and this is the cataftrophe, which crowns the tale of faf- cination ! - An attachment to our offspring is not peculiar to the human kind alone. It is an inftinét which pervades the univerfe of animals, It is a fpark of the divinity that a€tuates the greater number of living exiftences. It is a paflion which, in my mind, at leaft, declares, in language moft emphatic, the exiftence, the fuperintendance, the benevolence, of a firft great caufe, who regards with partial and parental, if not with equal eyes the falling of a fparrow and the falling of an empire. Among the greater number of the {pecies of birds, the at- tachment of the parent to the young is remarkably ftrong. We have daily inftances of this attachment among our domettic birds, and I believe, it is ftronger among thefe birds in their wild ftate: for there are fome reafons for {ufpeéting, that this amiable inftiné is diminifhed and weakened by culture *. *® This queftion will be examined in my memoirs upon the ftorge, er affeftions, of animals, The 110 ON THE FASCINATING FACULTY Fa@ts andob- The inftances which I have already mentioned, as well as a v: ervations re~ faét, which remains to be mentioned, point out, ina ftriking pecling the : power of fafci- view, the attachment of the mother-bird to her offspring. nation afcribed She often guards her ‘neft with the greateft attention, fearful — of the infidious glide of the ferpent. She endeavours to prevent the deftru€tion of her eggs or young, by thisenemy. When he has fucceeded in obtaining them, fhe attacks him either alone, or calls other birds to her affiftance. We ought not to be furprifed, that fometimes fhe falls a viétim to her affeétion. For it isa well known faé, that fome fpecies of birds will fuffer themfelves to be taken upon their nefts, rather than relinquifh their young, or their eggs. In the ftudy of natural hiftory, I am always happy to dif- cover new inftances of the wifdom of providence, and new proofs of the flrong affe€tions of animals. And for the dif- covery of fuch inftances of wifdom, and fuch proofs of affec- tion, the contemplation of nature is an ample field. In the inftances now before us, the ftrength of the inftinét of affec- tion in birds is illuftrated, in a ftriking point of view; and I cannot help obferving, that I feel an high degree of pleafure in being able to do away, in fome meafure at leaft, a pre- judice, not lefs extenfive than it is unfounded, by bearing my flender teftimony in favour of the exiftence and the powerful dominion of a benevolent principle in animals. The following fa€t was communicated to me, fome time fince, by our prefident, Mr. Rittenhoufe. I think it ftrikingly illuftrates and confirms the fyftem which I have been endea~ vouring to eftablifh, I relate it, therefore, with pleafure, and the more fo, as I have no doubt, that the authority of a. cautious and enlightened philofopher will greatly contribute to the deftru€tion of a fuperftitious notion which difgraces the page of natural hiftory. Some years fince, this ingenious gentleman was induced to fuppofe, from the peculiar melancholy cry of a red-winged- maize-thief*, that a {nake was at no great diftance from it, and that the bird was in diftrefs. He threw a ftone at the place from which the cry proceeded, which had the effeét of driving the bird away. The poor animal, however, im- * Commonly called, in Pennfylvania, the Swamp-Black- bird, It is the Oriolus pheeniceus of Linnzus, sicitiat ely ASCRIBED TO THE RATTLE-SNAKE, 1ii mediately returned to the fame fpot. Mr. Rittenhoufe now Faéts and obs went to the place where the bird alighted, and, to his great Pe hg g the aftonifhment, he found it perched upon the back of a large power of fafcie black-fnake, which it was pecking with its beak. At this nation afcribed to fnakes. very time, the ferpent was in the aét of {wallowing a young bird, and from the enlarged fize of the reptile’s belly it was evident, that it had already {wallowed two or three other young birds. After the fnake was neil the old bird flew away. Mr. Rittenhoufe fays, that the ony and ations of this bird had been precifely fimilar to thofe of a bird which is faid to be under the fafcinating influence of a ferpent; and I doubt not that this very inftance would, by many credulous perfons, have been adduced as’a proof of the exiftence of fuch a faculty. But what can be more evident than the general ex- planation of this cafe? The maize-thief builds its neft in low bufhes, the bottoms of which are the ufual haunts of the black- fnake. The reptile found no difficulty in gliding up to the neft, from which, moft probably in the abfence of the mother, .it had taken the young ones. Or it had feized the young ones, after they had been forced from the neft, by the mother, in either cafe, the mother had come to prevent them from being devoured. 3 Weare well acquainted with the common food of the rattle- _fnake. It is the great-frog* of our rivers, creeks, and other waters. The {nake lies infidioufly in wait for his prey, at the water-edge. He employs no machinery of enchantment. He trafts to his cunning and his ftrength. A very ingenious + friend of mine, who has devoted con. fiderable attention to the natural hiftory of the rattle-fnake, and who has diffeéted many of them, affures me, that he never faw but one inftance in which a bird was found in the ftomach of this reptile, and this bird was the chewink, or ground- robin}. In another inftance, he faw a ground-fquirrel § _ taken out of one of thefe reptiles. In every other cafe, fo long as the food retained enough of the form to be dif- tinguifhed, the ftomach was found to contain the great- frog, ‘which I have mentioned. * Rana ocellato of Linneus. > Timothy Matlack, ot ® t This is the Fringilla erythrophthalma of Linneus. hs | © & The Sciurus ftriatus of Linnzus. | Another 112 Faéts and ob. fervations re- fpe€ting the power of fafci- mation afcribed to fuakes. ON THE FASCINATING FACULTY Another argument againtt the fafcinating power of the ferpent-tribe {till remains to be confidered. : It is natural to inquire, for what purpofe nature has endued ferpents with the fuppofed powers of fafcinating birds, and other animals? The anfwer to this queftion is uniform, It is faid, the power is given that the ferpents may obtain their food. Let us‘examine this opinion, Admitting the exiftence of this power, I fhould have no hefitation in believing, that its ufe is what is here mentioned, though, indeed, it ought not to be concealed, that fnakes are fuppofed, by fome foolith people, to have the power of charm- ing even children. And yet, I believe, there are no in- ftances recorded of our American fnakes devouring children. If, then, nature, in the immenfity of her kindnefs, had gified the ferpents with this wonderful power, we fhould, at leaft, expect to find that the common and principal food of thefe ferpents was thofe animals, viz. birds and fquirrels, upon which this influence is generally obferved to be exerted. This, however, is by no means the cafe, . As conneéted with this part of my memoir, it will not be improper to obferve, that all our ferpents are the food of dif- ferent kinds of birds. Even the rattle-fnake, whofe poifon produces fuch alarming fymptoms in man, and other animals, is frequently devoured by fome of our ftronger and more courageous birds. As farasI can learn, the birds which moft commonly attack and deftroy this reptile, are the fwallow- tailed hawk *, and the larger kinds of owls, The owl often feeds her young with this fnake, whofe bones are frequently found in her neft, at confiderable heights from the ground. Even a hen has been known to leave, for a minute, her af- frighted chickens, and attack, with her beak, a rattle-{nake, the greater part of whofe vody fhe afterwards devoured t. * Falco furcatus. + It is commonly believed, that the rattle-fnake is a very hardy animal; but this is not the cafe. A very fmall ftroke on any part of its uot difables it from running at all; and the flighteft ftroke upon the top of the head is followed by inftant death. The fkull- bone is remarkably thin and brittle; fo much fo indeed, thatitis — thought that a itroke from a wing of a thrufh or robin would be fufficient to break it _ The ASCRIBED TO THE RAYTLE-SNAKE. 113 - The black-{nake is a ferpent of much more aétivity than the Faéts and ob= rattle-fnake, The latter, as I have already faid*, feldom, if aeawe aan ever, climbs up trees. But the former will fometimes afcend power of faf- the loftieft trees, in purfuit of the objeé of his appetite. The By ota rattle-fnake, it has been juft obferved, fubfifts principally upon the large frog, which frequents the waters of our coun« try. Hehas, therefore, but little occafion for aétivity. But the black-fnake, feeding more upon birds, ftands more in need of aétivity. He frequently glides up the trees of the foreft, &c. and, commonly in the abfence of the mother, devours either~her eggs or her young ones. The difficulty of obtaining his prey upon the tree is fometimes very con- fiderable, as will appear from a faét which will be related immediately. Now, if this ferpent is gifted with the faculty of fafcinating, why is he not content to continue at the bottom of the tree, and bring down his objeét? And if he can employ this machinery of fafcination at his pleafure, how comes it, that he fo feldom fucceeds in capturing old birds? For-it is a fagét that when birds are found in his ftomach, they are princi- pally young birds, I have faid, that the black-fnake fometimes finds great dif- ficulty in obtaining his prey upon the tree. In fupport of this aflertion I could adduce many fa€ts. But my memoir has already exceeded the limits which I originally prefcribed to it. I fhall content myfelf, therefore, with relating a folitary fact, which ftrikingly illuftrates my pofition. _ A black-fnake was feen climbing up a tree, evidently with the view of procuring the young birds in the neft of a balti more-bird.. This bird, it has been already obferved, fulpends its neft at the extremity of the branch of a tree. The branch to which the bird, of which I am fpeaking, had affixed its neft, being very flender, the ferpent found it impoffible to come at the neft by crawling along it: he, therefore, took the advantage of another branch, which hung above the nett, and twifting a fmall portion of his tail around it, he was enabled, by firetching the remainder of his body, to reach _ the neff, into which he infinuated his head, and thus glutted his appetite with the young birds, _. The importance of this faét, in the inveftigation of the fubje€&t of my memoir, appears to me to be great. An * See page 106. Vor. VII.—June, 1804, I American 114 Faéts and ob- fervations re- fpeéting the power of fafci- nation afcribed to fnakes. ON THE RATTLE-SNAKE, American foreft is not the filent refidence of a few birds. During the greater part of the fpring and fummer months, our woods are alive with the numerous fpecies of -refident and vifitant birds. At thefe times, if the black-fnake pofleffes ‘the faculty of fafeinating, it cannot be a difficult thing for him to procure his food, Yet, in the inftance which I have juft related, we have feen this reptile climbing up a tree, and there obliged to exert all his ingenuity to obtain his prey. | I cannot well conclude this memoir without obferving, that in the inveftigation of the fubjeé&t which it involves, I have experienced much pleafure. For to the cultivators of fcience, the difcovery of truth muft, at all times, be a fource of pleafure. This pleafure will even rife to fomething | like happinefs, when, in addition to the difcovery of truth, we are enabled to draw afide the veil, which, for ages, has curtained fuperftition and credulity.. Under the influence of various fpecies of fuperftition, we fall from our dignity, and are often rendered unhappy. It fhould be one of the principal objects of fcience to rear and prop the dignity of the mind, and to fmooth its way to comforts, and to happinefs. The ills and the infirmities of our earthly ftate of being are numerous enough. It is folly, if not vice, to increafe them. He who ferioufly believes, that an hideout reptile is gifted, from the facred fource of univerfal life and good, with the power of fafcinaling birds, fquirrels, and other animals, will hardly ftop here. He may, and probably will, believe much more. He will not, perhaps, think himfelf entirely exempted from this wonderful influence. He may fuppofe, that the property belongs to other beings, befides the ferpents; and he will, perhaps, imagine that it forms a part of a more extenfive plan, the effeéts of which, he will affert, are pro- minent, and unequivocal, though its ways, he will confefs, are incomprehenfible to mortal minds. Hiftorta naturalis non bene digefta abit in fabulam ; raid vero et nimia credulitas Veritatem, etfi cominus Jatis cognitam, — longifime aliquando propellunt. JACOBUS THEODORUS KLEIN. Some a ANCIENT EGYPTIAN LOCK, 115 XV. Some Account of an Egyptian Lock of very high Antiquity, In- dicated from Denon’s Travels, by a Correfpondent. With Obfervations by W. N. To Mr. NICHOLSON. ‘SIR, A FEW weeks ago I faw, with particular pleafure, a model, Letter concerri- or wooden lock, Hint from the defcription in Denon’s travels, '?& 3 'ock Mewn at ‘the Royal which was exhibited in the le@tures at the Royal Inftitution, I Infiitutions beg leave to propofe the infertion of the fame in your excellent Work, and fhould hope for your opinion as to its fecurity. J am, Sir, Your obliged reader > New Broad Street, P..Q. led 12, 1804. I HAVE given engravings of this lock, copied from De- Defcription of non’s book, Plate VIL. fhews the lock as applied to a door, the lock, and its developement is made in Plate VIII. The paffage in Denon (tranflated) is as follows: . «No. 2, 3, 4,and 6. The Egyptian lock, It fecures the _ gates of towns, of houfes, and the apertures of the {malleft articles of furniture or ufe. I have placed it among the anti- quities, becaufe it is the fame as was in ufe four thoufand years ago. I found one fculptured among the bal-reliefs which de- feulptured on -corate the great temple of Karnack. It is fimple in concep- the gree! saat ‘tion, ealy of execution, no lefs fure than any other lock, and -deferves to be applied on all our rural occafions. Fig. 2 is the key, which is capable of thoufands of different combinations. In Fig. 3 the lock is fhewn clofed, feen as to its interior; the key being in the aét of lifting up certain pins which had fallen -into holes in the bolt, and kept it in its place. In Fig. 1 the »bolt is drawn back, and the lock confequently open.” See plate 139 of the fard work. Eton, in his Survey of the Turkith Empire, mentions this lock as follows: ** Nothing can be more clumfy than the door-locks in Eton’s account Turkey, but their mechanifm to prevent picking is admirable, °f the fame lock as of univerfal 12 It uf in Turkeys Sc. 116 ANCIENT EGYPTIAN LOCK, It is a curious thing to fee wooden locks upon iron doors, par- ticularly in Afia, and on their caravanfaries and other great buildings, as well as on houfe doors. The key goes into the back part of the bolt, and is compofed of a fquare ftick with five or fix iron or wooden pins about half an inch long, to- wards the end of it, placed at irrregular diftances, and an- fwering to holes in the upper part of the bolt, which is pierced with a fquare hole to receive the key. The key being put in as far as it will go, is then lifted up, and the pins entering correfponding holes raife other pins, which had dropt into thefe holes from the part of the lock immediately above, and which have heads to prevent them falling lower than is ne- ceflary. The bolt being thus freed from the upper pins, is drawn back by means of the key, the key is then lowered, and may be drawn out of the bolt: to lock il again the bolt is only pufhed in, and the upper pins fall into the holes of their own weight. This idea pies be improved on, but the Turks never think of improving.’ —— Obfervations. THE fimplicity and other advantages of this lock or bolt, are too obvious to require much remark; for which reafon I fhall confine my prefent obfervations to its degree of fecurity or inviolability, I think we may contemplate it in three feve- Simpleft ftruc- ral ftages of perfection or improvement. 1. If it be con- - | ture of this lock ftryéted with one pin of confiderable fize to fall into the bolt, | is a kind of 2 | latch and the finger be fuppofed to be introduced for the purpofe of raifing it and fetting the bolt at liberty, we fhall have a faften- ff The prefent | ing of nearly the fame effect as the common latch. 2. Or if, lock, inftead of one falling pin, there be many, and an inftrument | be ufed to lift them, we fhall have the bolt before us: and this, as far as we are informed, is the prefent ftate of the J Probable im- invention, though of fo long ftanding. 3. Or thirdly, in cafe PROWEMANIs the prefent bolt fhould, on examination, be found to admit of # j being opened without extreme difficulty, it will become a } queftion whether the principles of its ftru€ture can be fo ap- 1 plied as to render it abfolutely fafe. This laft queftion requires that we fhould firfl examine the ancient bolt a little more clofely. 1 This lock can- | We may admit that the ancient lock, with many pins falling } Bot be picked; independently of each other, cannot be ‘picked or opened — without its key; and therefore we muft afk whether the key can ¢ ANCIENT EGYPTIAN LOCK. BLY can be made from an examination of the lock alone? In anfwer to this it may be noticed, that fince all the pins in the key muft be of equal height, the fecret will confift in their relative diftances and pofitions on the face of the key ; and that thefe diftances and pofitions can be eafily known by intro- _ ducing a ftick, or key without pins, into the hollow of the bolt, and taking an impreffion (by means of a facing of foft _ clay) of the holes intended to receive the pins. After this a but its key may key may be made without difficulty ; fo that we arrive at our e ace a conclufion, that though this ingenious piece of mechanifm SR. cannot be violated without its key, yet it is eafy to conftruét a key for that purpofe, We now come to the enquiry afier that application of its Improvement by principles which may render ‘it abfolutely fate. This is cer- Ae is rene it ‘ sis tenn atari . dered fafe, tainly poffible ; but not without confiderably diminifhing its _ fimplicity. Befides feveral others, the following may be pro- pefed: Let the dropping pin have an enlarged part, and a tail of wire above and below. Let the lower tail fall into its hole in the bolt, while the enlarged part falls into a focket made for its reception. Under thefe circumftances the bolt becomes faft: But when by raifing the pin the enlarged part is clear of its focket, the bolt becomes free, and the lower tail is prevented from ftopping it by a groove left for its re- ception. The bolt muift have a covering piece of board, having a hole of the fize of the enlarged part of the pin, direétly _ above the focket into which it falls, and a groove for its upper tail; the interval between the covering-piece and the bolt itfelf being equal to the height of the enlarged part of the pin. By this means, when the pin is pufhed up, juft out of its focket, the bolt will move freely ; but if it be pufhed the leaft quantity farther, the enlarged part will enter the hole in the covering-board, and fet it faft, as if it were in the focket; fo that a very precife diftance of elevation will be requifite, Laftly, the lower pin may be fhorter or longer at pleafure. Now, if there be a number of thefe pins fo placed and ad- jufted as to fall into their refpe€tive fockets at the pofition of the bolt when fhut; if their lower tails be of different lengths, and a key be made to correfpond with them, and lift them all to the proper height at once; the combination will be fuch as cannot be made out by any impreffion or tentative procefs upon the lock itfelf, For the evidence of a due length of any fy 0 . - one 118 Precipitation of the folution of platina. Remarks. Foreign admix~ tures in crude platina. ON PLATINA. one of the lifting pieces of the key, will confift in the actual opening of the lock; and this cannot be had unlefs the due length of all the pins be obtained at once; againft which the probability will be asthe number of permutations of the pins, multiplied into the number of poffible lengths of pins praétically differing from each other in effe@. Thus if the pins were fix, the permutations would be 1x2x3x4x5x6=720; and if the length of a whole pin were one quarter of an inch, and a fenfible difference would in praétice arife from making the pins one-fixtieth of an inch longer or fhorter, there would be 15 poftible lengths for every pin. Whence 720x 15= 10800, the number of chances againft the difcovery. W.N. po SRR SS SS SS ee AVI. On the Caufe of the different Colours of the Triple Sets of Platina, and on the Exiftence of a new Metallic Subftance in that Metal. By Cotzer-Descotirs.* Prefented to the Clafs of Mathe- matical and Phyfical Sciences of the National Injitute of France. me Au chemifts know that crude platina is eafily foluble only in nitro-muriatic acid, thatthe folution is decompofable by muriate of ammonia and other falts with alkaline bafes; and that the refult of their former decompofition is a triple compound, confifting of oxid of platina, muriatic acid, and ammonia, or the alkaliemployed. The colour of this precipitate varies from a light yellow toa dark brown. It is fometimes alfo greenifh. The latter is the cafe if the folution of platina is precipitated by a falt with bafe of foda, Before I fay any thing further concerning the caufes which influence the colour of this precipitate, I hall point out fome phenomena which characterife the folution of the metal itfelf, The grains of platina of commerce always contain more or lefs of foreign mixtures from which it fhould be previoufly freed. i as much as poffible. The foreign bodies met with are moft fre- quently minute ftones, on which the acid employed for diffolv- ing the metal, -has little or no a@ion, and two forts of ferrugi- * Gchlen’s Chemical Journal, Vol. II. Part I. p. 73. nous ON PLATINA. 119 nous fand, one of which is obedient to the magnet, and an- other which is not attracted by the magnet, and which is only partially aéted on by acids. I hall fay no more in this place The ferruginoug concerning thefe bodies, but that the firft contains titanium and ce the fecond chromic acid, in confiderable quantity. chromic acid. The beft method to free platina of commerce from thefe ad- Mechanical mixtures, is that recommended by Prouft, which conjifts in “aay by {fpreading out the platina on a fheet of paper, and carefully blowing away the lighter parts by means of a pair of bellows, Platina thus purified Iintroduced into a porcelain retort, to Crude platina by which a glafs receiver had been fitted, previoufly filled one- saya aise third full of water: After having placed the retort in a re- blue fublimate verberatory furnace, I raifed the fire gradually, and increafed {!ble in watere __ the heat to the utmoft Icould produce, which was kept up for two hours. Nothing particular attended this procefs, except that the water with which the receiver had been partly filled, acquired a greenifh hue towards the end of the procefs. On the roof of the retort, a fine blue powder was fublimed, of which I fhall fay no more at prefent than that it was foluble in water. The water inthe receiver, after having been fuffered to ftand for a few days, had acquired a beautiful blue colour, which furpaffed the colour of the beft ultramarine. It was impoffible to get the platina out of the retort. On The platina breaking the diftillatory veffel, the metal was found aglutinated, pe my the upper furface of the mafs had a rufty appearance, the . middle was lefs difcoloured, and the lower part had fuffered no perceptible change. ‘In order to examine the colouring matter which tinged the The aqueous‘ water of the receiver, I dropt into it a folution of an alcali; aibagperine 3 this produced inftantly a blue precipitate. Sulphuric and mu- forded a precipi« riatic acids, when mingled with this fluid, occafioned no Each change. Nitric and oxiginized muriatic acids changed this acids). &cs blue fluid, firft toa lilac, but it foon loft this colour, and the whole became limpid. Water holding in folution fulphuretted _ hydrogen gas, occafioned no precipitate; but hidro-fulphuret _ of ammonia threw down a grey precipitate, which became blue by the affufion of acids, and then was rendered foluble ~ again in hidro-fulphuret of ammonia. A {mall quantity of the blue precipitate collected from the The He fubli- ‘roof of the retort, when urged with the blow-pipe in con- ee oy een aét with borax, imparted no colour to this:falt. When heated pipe: it did not per fe, it difappeared completely. Nearest - ‘Having 120 ON PLATINA. When platinais Having fo far proceeded, I made a folution of platina in diffolved inn. nitro-muriatic acid (the platina had been freed from iron as poh Oe to much as poffible by muriatic acid.) During this folution, a ee : glittering black powder became feparated, as is always the cafe when platina of commerce is diffolved’ in nitro-muriatic © acid. If the operator be careful in colle€ting this powder as faft as it is feparated, the quantity which may be colleéted, amounts to about 0,03 of the platina employed. But if this powder be not removed as faft as it is depofited in the folution, part of it becomes again acted upon, and a much lefs quantity is obtained. . Muriate of pl. The muriate of platina obtained, after having been fuffered- aah aap gt to repofe and being decanted, I decompofed by adding by a ants... " *™° faturated folution of muriate of ammonia; the precipitate was feparated by decanting the fupernatant fluid, and repeatedly wahhed till the water which paffed, did not become green by the addition of pruffiate of potafh. The precipitate obtained Yellow precipie Was of a yellow colour. The decanted fluid from which the tales precipitate had been feparated, and the firft quantity of water employed for its ablution, after having been-mingled together The decantea and concentrated by evaporation to one third of its bulk, were fluid being con- again mixed with a folution of muriate of ammonia; the pre- nascar, of cipilate now obtained was of a dark red colour. On treating amm. added, a thie fluid feparated from it, as before, the precipitate which did oe il fall down was of a very dark brown. All thefe different co- ed. loured precipitates were carefully wathed till they contained no The fluida —_yeftige of copper or iron. fecond time : : : decanted gave by 1 have remarked that if the folution of platina be flowly pre- mur. amm.a pared, that is to fay, if the platina be introduced into the dark brown . sae ot tel oe : precip. nitro-muriatic acid, in {mall quantities at a time, and the fub- ei colour of fequent folution of each quantity be refpeCtively feparated, and Hee an feparately be decompofed by muriate of ammonia, the colour the more of the of the precipitate or triple falt obtained, is darker in propor- black d : - : : ‘Sig ool tion to the quantity of the black powder which was contained in the folution. The black pow- This black powder which is depofited during the folution of mv) patag sti platina of commerce * in nitro-muriatic acid, is foluble (though oluole in nitr. . . . LN . i m. acid; and ifficultly) in nitro-muriatic acid, compofed of much nitric, decomp. by mur. and little muriatic acid; its folution is alfo decompofable by of am. * This black powder is likewife feparated during the folution of malleable platina in nitro-muriatic acid. F. A. muriate ON PLATINA. 121 muriate of ammonia, and the colour of the precipitate is more | or lefs intenfe, according to the quantity of powder contained * in the folution. . From what has been fo far ftated, it appears, that this black — pow powder is the caufe of the different colours which the different cea engi precipitates or triple falts of platina exhibit, under different precipitates. circumftances. In order to learn the nature of this fubftance, I fhall detail Enquiry into the experiments which were undertaken for that purpofe. The ee precipitates or falts I made ufe of were, the triple ammoniacal muriate of platina, and the triple muriate of platina and foda; the former falt I preferred on account of its eafy decompofibi- lity, and the latter on account of being very foluble. Experiments on the triple ammoniacal Muriate of Platina. Equal quantities of the before-obtained yellow and dark red Aqueous folus aly he Be 2 : rtions of the yel- precipitate, being feparately diffolved in equal quantites of)” dediMare tect water, the firft falt furnifhed a folution of a gold yellow colour, precipitates; the whereas that of the latter was orange red. On adding to the “'# gold-yellow, se , é : the fecond orange Jatter folution a minute quantity of green fulphate of iron, oF ted, fulphureous acid, it became inftantly of a gold yellow colour; The latter was the fame effect was produced, though flowly, by the addition ae mee alcohol. of gr. fulph. of It was natural to fuppofe that the colour of the red falt (03 * by al- might be owing to the higher degree of oxidizement of the The red colour _ diffolved platina. In order to convince myfelf of this conjec- 5 2°t owing: f : 3 to greater oxie ture, I altempted to transfer oxigen to the yellow falt, by means dizements of nitric and oxiginized muriatic acids. This however failed; the colour of the falt remained yeilow as before. On repeating the application of nitric and oxiginized muriatic acids alter- nately, the refult was only a very pale red coloured precipitate. © Equal parts of the yellow and red precipitate, deficcated at The yellow and equal temperatures, and under the fame circumftances, when td sy f ait oO not decompofed by heat, yield alfo unequal quantities of fixed re- pis ne pl fidue. That of the firft, amounted to 0,44 of the weight of when decom- the falt employed, and that of the latter was 0,4 and 5. poled hy Heat. If yellow precipitate be reduced by heat, the platina ob- The yellow tained is uncommonly foluble in a comparatively fmall quan- precipitate if re- tity of nitro-muriatic acid, and the folution yield a yellow pre- si ig cipitate with muriate of ammonia. platina ; which If again affords a yellow precip, 122 ON PLATINA. The red preci-. If the red precipitate be reduced, the metal obtained is of pitate affords a 4 different nature from the former. It is far more infoluble in Jefs foluble metal bites. f : i which leaves a nitro-muriatic acid, and whatever quantity of acid may be black powdery applied, there remains conftantly a quantity of black powder, and affordsared |. . shine : ; 5 5 precip. which is abfolutely’infoluble in the acid. This folution, on be- ing decompofed by muriate of ammonia, yields a red precipi- tate. This Heap To learn the nature of this precipitate, I reduced a quan- treated with ox-,- bras ee ; er ‘ iginiaed mutiate tly’ of it, introduced it into a porcelain tube, connetted with of potafh with a fmall retort, containing hyper-oxiginized muriate of potath, beats and applied heat to the retort, after having firft adapted to the other extremity of a receiver containing alittle water. On in- creafing the heat fo as to decompofe the hyper-oxiginized mu- Blue powder _riate, the tube became lined with a blue powder, which was obtained 5 alfo obferved in the empty part of the receiver. After all the falt in the retort had been decompofed, I col- lected the blue fublimed powder. The minute quantity of it however did not permit me to fubmit it to many experiments, —folublein [t was eafily foluble in nitro-muriatic acid. Its nature will eae become more obvious hereafter. The red colour From what has been fo far ftated, it appears to follow that arifes from 2 the red colour of the triple precipitate of platina, obtained by peculiar metal. 5 4 eles : muriate of ammonia, or other falts with alkaline bafes, is ow- ing to the prefence of a peculiar metal contained in the pla- tina, which has hitherto been confidered as fimple. Examination of the triple Muriate of Platina and Soda. Triple muriate ‘This triple compound is very little known.* It may eafily aoe and be obtained by pouring into a folution of platina, a falt with bafe of foda. It is very foluble in water, and even in alcohol. The folutions are capable of cryftallizing in long prifms, on three-fided tables, of a yellowifh red colour. It is decom- pofable by muriate of ammonia; the precipitate is a mufiate of platina and ammonia. It is likewife decompofed by a fo- lution of fodas on adding this alcali in excefs, the formed pre- cipilate becomes again diffolved. Reducible on Muriate of platina and foda is reducible upon charcoal be- ak ly the fore the blow-pipe. The reduced metal poffeffed a confider- able luftre. * Muffin-Pufchkin has pcinted out fome of its properties in Crell’s Annales, 1800, Vol. I. p. 93. of which a thort abftra& is to be found in the Annales de Chimie. p, 277. 2 Ft; if - fure to air. ON PLATINA. 123 If cryftallized muriate of platina and foda, free from all ad- Its eryftals from hering or excefs of acid, be expofed for fome time to the air, otal, its beautiful red colour becomes changed into a greenifh hue. expofure to the If the falt in that ftate be diffolved in water, and oxiginized Sih te muriate of lime be added to it, a dark brown precipitate falls, precip. by ox. which after having been wafhed and dried, is foluble in mu- ™¥siate of lime. riatic acid, with which it forms a beautiful blue foluiton. This colour becomes again deftroyed by the admixture of alcohol, and re-appears by the addition of oxiginized muriate of lime. This precipitate is fomewhat foluble in water; itis reducible shape ni gs when fufed with borax, without imparting to the latter any co- reducible Ran lour. The reduced metal is very porous: it appeared not to 4 porous metal be foluble in any of the acids. eo = If the folution of muriate of platina and foda, contain an No precipitate excefs of acid, it then is not difturbed by letting fall into it hon be im Oxiginized muriate of lime; but on evaporation the mixture : acquires a fine green colour, \ ‘Examination of the Yellow and Red triple Muriate of Platina. _ If weadd to the red triple muriate of platina, a folution of The red triple muriate becomes carbonate of foda, till it becomes completely diffolved the fo- yeilow by carbo- lution is of a yellow colour. On expofing it for fome time to te of foda 5 . . ~ ° ene, d the contact of air, a green fubftance becomes depofited. ech a The yellow triple muriate of platina, treated in a like man- expo to the Z ; . : : aire ner with carbonate of foda, yields a folution of a dark yellow, 7. pelloerubiais er orange colour, which fuffers no change whatever on expo- treated becomes darker, and does i : not afterwards - The feparation of the green fubftance from the red triple change. muriate, is much accelerated by the admixture of oxiginized rhe aie Pana oi ge . : ‘ ~ - ; it from ¢. muriatic acid. . It feems as if the feparation of this fubftance triple pe 4 s is owing to the aétion of oxigen; for no other acid is capable ftom oxidize- of producing it; al-leaft the precipitate which they produce,. ae i is a mere oxid of platina, The green fubflance may likewife be inftantly obtained by It is inftantly had by evapora= — evaporating the folution by heat. : ; Pp g 4 tion. If the folution of the yellow triple muriate be heated and The yellow i 2 : ; ._ triple muriate evaporated, a very minute quantity of the green fubftance is may afford a mie indeed, fometimes depofited, and the remaining folution then nute portion of : : enlut green precip. by acquires a more beautiful yellow colour. On continuing the eva Seine thite evaporation of the yellow folution, a precipilate is depofited, is an impurity, ‘ “ap, Ats precip. is which qllowey 12t ON PLATINA, which is not green, but yellow. This precipitate on being again diffolved in murtatic acid, and faturated with carbonate of foda, yields no farther green fubftance. . The greenpre- [mingled a quantity of this green fubftance with vitrified cipitate was re= duced (by heat with borax) toa nutes in a double crucible to the moft intenfe heat I could pro- hs ati duce; the refult was a white brittle metal, which was difficultly difficultly ated aéted upon by nitro-muriatic acid. The weak folution which on by nitro-m- had been obtained by this acid, had a violet colour; it yielded, pt on being evaporated, a dark green refidue, which was foluble in muriatic acid, with which it formed a green fluid, more fo when On pulverizing another quantity of this white brittle metal, powdered. and then expofing it to the aétion of nitro-muriatic acid, the folution was effeéted more eafily, it was now more concen- trated, and of a reddifh-yellow colour. Muriate of ammonia let fall into it, threw down a little brownifh-red precipitate, a proof that this metal ftill contained platina. The folution of | A quantity of the before-mentioned green fubftance being ol armel diffolved in muriatic acid, acquired a yellowifh colour on be- yellowith by ful- ing mingled with fulphureous acid, or with a folution of green phureous acid or muriate of iron. Osxigenized muriate of lime reftored the green muriate of jron. ofiginal green colour. 5 Ox. mur, of | A third part of the green fubftance, on being expofed to Iime reftored its ; : j J : green. a violent heat in a porcelain retort, yielded a blackifh-blue The green fub- fublimate: the unfublimed part was a metallic fub{tance, very ereitaete difficultly foluble in nitro-muriatic acid. and left metal. A fourth portion of the green fubftance was urged, in a. A portion of the : . : Fit Pe crucible head, with nitrate of potafh. After the decompofi- heated with = tion of the nitrate had been completed, the mafs was dif- nitre till the acid fufed through water. The alkaline folution was colourlefs, was decompofed. The alkali was aNd acids produced no change of colour in it. The refidue, diffolved in war after repeated ablutions, was hardly aéted upon by acids, the ter, and not changed by nitro-muriatic acid not excepted. This experiment precludes _ acids, the prefence of chrome and molybdena. The refid : . : rin 3 not aéted on by Lt is poflible to feparate nearly all the platina which is con- acids. tained in the red triple muriate, by the mere admixture of al- SO Ma cohol, and the fubfequent addition of dry potath or foda; for were ab(ent. doing this much heat is evolved, and the reduétion of platina Separation of the platina from 3 the triple muri- Means of carbonate of potafh or foda; but in that cafe the fo- ate by alcohole ution muft be highly concentrated. The reduétion. of the . platina borate of foda, and expofed the mixture for twenty-five mi- takes place almoft inftantly. The fame. may be effeGted by. : j . * ON PLATINA, _ 125 platina then.takes place even without the application of heat, but only after the {pace of fome days. The fupernatant fluid of the reduced platina, when heated, The fupernatant acquires a lilac colour, which becomes blue on long expofure ee med to air, depofiting at laft a greenifh fubftance, refembling that hitherto treated of. Oxigenized muriatic acid favours the feparation of this fubftance. Sulphuretted hidrogen may alfo be employed for feparating Sulphuretted hi- the platina from the red triple muriate ; the platina becomes fe- wt fepa- parated in the form of a brown powder ; the other metallic fub- saan gu ftance remains undifturbed in the folution. It may, however, al- moft totally be precipitated by liquid ammonia. The precipitate . obtained is brown. When fufed with potafh in a filver cru- cible, the mafs acquires a green colour: On pouring muriatic acid on it, no complete folution could be effeéted ; there al- ways remained a powdery fediment which refifted likewife the aétion of nitro-muriatic acid. Carbonate of potath fepa- rated from this folution a {mall quantity of iron. The clear ' fluid from which the iron had been feparated, remained per- fectly tranfparent when heated ; but it aqquired a bluifh hue, which increafed on concentration, and after the exficcation of the falt. On adding a little nitric acid to the falt, the blue colour became changed into a dark red. CONCLUSION. I now flatter myfelf with having proved, by the above experi- Conclufion. ments, that the red coloured triple falts of platina owe their The red colour colour to the prefence of a peculiar metal, oxidized to a cer- *® oe een eins Blignses culiar oxide, That this metal is nearly wholly infoluble in acids; that it nearly infoluble becomes foluble in combination with platina; that when ox- = es Bea idized, it appears in the form of a blue oxide inclining to green; vidio, rhe that its oxides, when combined with platina, are foluble in al- calies; that its acid folutions are not decompofable by fulphu- tetted hidrogen; that it imparts no colour to borax; that its oxides are reducible and volatilizable by heat, which vo- latilization becomes favoured by a ftream of oxigen gas ; and, lafily, that oxigen gas, affifted by heat, is capable of oxidizing this metal, and of volatilizing it in the form of a blue oxide, Thefe 126 The new metal not yet named. Apparatus for filtering water. FILTERING APPARATUS. Thefe properties do not charaéterize any of the known me- tals, and 1 am therefore authorized to confider it as a new one, to which I fhall give.a name when I have explored its nature more fully, XVII. Defeription of an Apparatus for filtering Water. By Meg: Harman and Dearn, of Redriff. ‘Tue waters which run near or upon the furface of the earth, are ufwally contaminated by the remains of animal and veges table fubftances in their progrels towards entire decompofition, as well as by the minute powder of earthy or mineral bodies; which render it turbid and lefs fit for the purpofes of domeftie life. Spring or pump waters, by a natural filtration through the fandy ftrata of the ground, are moftly cleared from thefe mechanical admixtures; but in many places, as is the cafe with thofe of our metropolis, they are rendered impure, or, as itis called, hard, by an aétual foluiion of fulphate of lime or plafter of Paris, which prevents their lathering with foap, aad probably renders them lefs wholefome; befides which, they ufually carry a portion of the drainage water in great towns, | which renders them offenfive at certain feafons, and at all times lefs worthy of confidence. For thefe and numerous other reafons, it has always been confidered as a defirable objeét to clear waters, by filtration, from thofe impurities which ren- der them lefs limpid, and a variety of apparatus have been offered to the public for that purpofe. In all thefe the procefs of nature has been imitated ; namely, by caufing the water to percolate either through fand or a fand-ftone ; the latter of which, though coftly, feems at pre-. fent to be almoft the only method in ufe among us. The contrivers of the fimple and cheap apparatus delineated in Plate VI..are Mefl. Harman and Dearn, potters at Redriff, who remark, that the filtering-ftone is not only expenfive and liable to be clogged up and fpoiled by the bodies depofited in its pores from the water, but that, as thefe bodies are aétually in the progrefs to decay and decompofition, they are in fome. cafes found aétually to change the flavour and affeét the purity of STONE CONTAINING POTASH. 127 of the fluid they are made ufe of to ameliorate. In confe- Apparatus for . : : filtering waters quence of which, they have been induced to apply their art to» the fimpleft method of affording an apparatus for the filtering procefs, which fhall not be liable to thefe objeétions. Plate VI. Fig. 1, reprefents the whole apparatus. Fig. 2 fhews a fhaded fe@tion. A is a veffel“of ftone-ware perforated with holes, m, at bottom, upon which coarfe gravel, h, is laid, and upon that a ftratum of fine gravel, and laftly fine fand, g. Or otherwife, the bottom may be covered with a coarfe cloth, which will render the graduated finenefs of the gravel and fand lefs neceffary. Upon the top of the fand is laid a perforated and loaded board or plate of earthen ware, to _ prevent the fand from being difturbed when the water is poured in. B isa lower veffel, into which the filtered water from A drops, together with any fand that may efcape from above. The clear water flows out through the neck ac into the veffel D for ufe. The ftru€ture, ufes, and effeéts of this apparatus are fo ob- vious, that it is needlefs to enlarge upon them. The finenefs and depth of the, filiceous fand will regulate the perfe@ion and expedition of the procefs; and the requifite cleannefs and delicacy of the veffels and fand may be infured by changing the latter from time to time; for example, once in a fortnight or three weeks. W.N. XVIII. Examination of a Stone containing Potafh. By Freperic Accum, Teacher of Pra@ical Chemifiry, Pharmacy, and Mineralogy. To Mr. NICHOLSON. SIR, : Since Klaproth has deteéted potafh in the lepidolite, Introduétory leucite, and fonorous porphyry, chemifts have fought for this etter. alkali in other minerals, and their enquiries have not been difappointed : Tromfdorff has found it lately in the augite, and no doubt this alkali will be met with in many other mi- _nerals in which it was not expeéted. Being called upon by the company of potters of Staffordfhire to examine a variety i of 128 STONE CONTAINING POTASH. of ftones employed in the manufaétory of earthen-ware, a par- ticularly exaét analyfis was demanded of a ftone, labelled grey Cornifh *, in which I deteéted this alkali. I fhall not detain you with a circumftantial detail of my reiterated experiments, which were undertaken with a view to learn the nature of the — fone under confideration, which is. fought for by the potters with avidity ; I fhall merely confine myfelf to point out its charaéters, as well as that examination which may ferve to eftablifh the credit of my affertion. Iam, Sir, with refpeét, Your moft obedient humble fervunk’ FREDERICK ACCUM. Old Compton Street, Soho. . \ = Gi Phyfical Chara&ers of a Siliceous Stone containing Potafh. ’ i charac- THIS ftone is found in amorphous maffes, forming irregular ters of aftone ftrata, under the furface of a blue clay. Its colour, when oaining Pt newly taken from the bed, is a greenith-grey interfperfed with black {pots ; but when left expofed to the air, it acquires an afh-grey colour, It is not very hard; its powder is white. When rubbed, ‘it exhales a faint argillaceous odour. Its fub- fiance is coarfe or uneven, having many fmall, fharp, abrupt, irregular elevations and irregularities. Its fraéture i8 very if- regular. It may be eafily fcratched with a knife. -It feinti- lates with fteel. Itis abfolutely opaque in fmall fragments. Urged before the blow-pipe, it froths and melts into a white enamel, Treated with borax in a fimilar way, it ei a reddifh bead. Its {pecific gravity is 2,465. ANALYSIS. Aiialgiin of 4 "Experiment I.—One hundred grains of the finely levigated i ftone containing ftone, after having been previonfly ignited +, were mixt with © peta a folution of potafh containing 400 grains of alkali, ‘the mix- ture was evaporated in a filver capfcel to a Mansferred ? * I am not permitted to ftate the exact yg in Cornwall where this ftone is found. + 100 parts loft, during ignition, 6 parts. into ; STONE CONTAINING POTASH, 129 into a crucible of filver, and fufed for half an hour. The fufed Analyfis of a mafs had rather a pafty appearance, and could not be rendered ,, ae ning perfectly fluid. Exp. [I:—As foon as the crucible was nearly cold, it was removed from the furnace, its contents were foftened by water, and the affufion of this fluid renewed from time to time, till all the fufed mafs was detached from the crucible: about 18 times its quantity of water were expended for that purpofe. Exp. IJI.—Into the obtained alkaline imperfeé folution of muriatic acid was gradually poured, and the whole evaporated to drynefs, Exp. IV.—The mafs was then transferred into a flafk con- taining dilute muriatic acid, the whole was fuffered to boil for a few minutes, and the infoluble part feparated by the filtre. The filiceous earths thus obtained had a greyifh ap- _ pearance, but it acquired a white colour after having beer _ again digefted in muriatic acid, dried and ignited. It weighed 58 grains, Exp. V.—The fiuid from which this quantity of filex had been feparated, together with the muriatic acid employed for purifying it, and the water expended for ablution, were con- centrated to about 20 cubic inches, and then mingled, boiling | hot, with a folution of carbonate of foda; the precipitate dee | pofited was collected, and wahed as ufual. _ Exp. VI.—As foon as the precipitate was fo dry that it could be removed from the filtre without lofing part of it, it was transferred into a folution of potafh, and the mixture boiled for about half an hour. On futfering the alkaline folution to ftand undifturbed for twenty-four hours, a powder was depo- fited, which, on being again boiled in a more concentrated folution of potath, remained unaltered. It was therefore col- _leGted, wafhed, dried, ignited, and put afide for further exa- mination. £xp. VT.—Into the alkaline folution, freed from this pow- der, I now dropt muriatic acid, till the precipitate which firft appeared again vanifhed, and then decompofed it by the ad- dition of carbonate of ammonia. The precipitate obtained in this experiment, after repeated ablutions and ignition, amount- ed to 28 grains. Experiments not effential to.be ftated here, convinced me that it was alumine. Vou. VIII.—June, 1804. K Bap.” 130 Analyfis ofa. ftone containing: potafh. , STONE, CONTAINING POTASH. Exp, VIII.—The precipitate of this experiment was diffolved in nitro-muriatic acid, and then mingled with liquid ame- monia. A brown precipitate became depofited, which, afler being dried, amounted to 0,25 grains. It was oxide of iron. The fluid from which this iron had been feparated, peg no other produéts, on being carefully examined, except two grains of filex which efcaped feparation. Thus far the ftone had yielded filiceous earth, alumine and oxide of iron. J fhall fupprefs thofe enquiries which proved fruitlefs for learning its farther compofition, and ftate merely thofe which were attended with fuccefs for that purpofe, and which were as follow: Exp. [X.—One hundred grains of the flone reduced to an impalpable powder, were triturated with 600 grains of cry{- tallized nitrate of barytes: the mixture fufed till the flame of a © - piece of ignited wood did not become enlarged when held. clofe over the furface of the fufing mafs. Exp. X.—The melted mals was foftened with water, and digefted in muriatic acid; the fluid filtered, and the refidue wafhed. Exp. XI.—The liquid obtained in this procefs I neutralized. — | with carbonate of ammonia, and added the latter till no further -cloudinefs enfued. After having feparated the precipitate, I evaporated the fluid to drynefs: the obtained falt I transferred into a glafs tube clofed at one end, and committed it to fubli- mation. | Exp. XIJ,—After the fublimation had ceafed (which was] known by a metallic wire introduced into the tube during the procefs, not becoming in the leaft covered with a coat of falt), I broke the tube and feparated the falt, This being — diffolved in water and cryttallized, yielded nine grains of mu- | riate of foda, Exp. XLI1I.—To fecodaiate this falt, I rediffolved it in water, and mingled the folution with nitrate of filver till no. farther cloudinefs. appeared: I then feparated the muriate of — filver formed, and decompofed the nitrate of potafh by heat, — which yielded 4,50 of potafh, : The, TEMPERATURE OF THE SEA. 4A3f _» Thevanalyfis being thus completed, T learnt that 100 grains Analyfis of a of this filiceous ftone from’ Cornwall contain, se containing Silex, a 2 = 60 Alamina, . « = - 28 Oxide of iron, | - - 0,25 Potafh, «'. - = = . 4,50) Water, - < ~ 6 98,75 Lofs, . 1,25 100 XIX. Letter from A, Caruisie, Efy. on the Temperature of the Sea. To Mr. NICHOLSON. Dear Sir, Soho Square, May 28, 1804. Tue following table was made by Mr. R. Perrins, furgeon Table of the on the’ Honourable E. I, Company’s eftablifhment, during a temperature of voyage to Bombay in the year 1800. The temperatures in nce this table were noted at my requeft, from a defire to deter- mine whether fifhes poffefs any other temperature than that of the water in which they live, the negative being afferted by Linnzus. As, however, this imperfect journal may affift in fimilar refearches, I beg leave to offer it for the ufe of your periodical work. Iam, Sir, Your much obliged fervant, ANTHONY CARLISLE, Ke *© Reoifter 132 Table of the temperature of the fea, &c. TEMPERATURE OF THE SEA. © Regifter of Atmofpheric Temperatures, collated with thofe of the Sea-Water taken on board the Honourable E> I. Company’s- extra Ship Skelton Caftle.”’ Atmo- 1800. {phere. Sea- Water. Feb, 28 ig a 42° 34! 13° 25° March2 | * ; 4 * 57 86 47 15 7 : 62 33 619 17. 34 2 aii (aS 31 58 ; 50 11 ™ 66 “30 26 20 49 13 i * 67 No obferv. 59 15 | ZU [tee 26 23 24 16 | 72 | 692 25 49 Q4 17 72 70 21 14 55 18 74 Te, 18 16 96 12 19 74 12 oe ey, 47 20 75 72 13,3) a2 24 49 Zl 76 74 ll 58 PAS 6 22 «|... 78. gas 9 46 aL” Bie be 23 80 78 7 43 20.. 11 24. 82 80 D5 9 13 23 82 80 4 24 20 6 26 84 82 3. 33 19 41 27 84 §2 2 58 19 27 28 85 §2 pagans 5) 19 V7 29 86 §3 Pe 7. 19 10 30 86 83 35 20 1 31 85 82 33 S. 19 April 1 | 84) | 81 2427 20. 41 2 83 80 A 44 eee | 3 82 80 Tan 293 AT 4 83 §0 9 50 94, ~50 §) 82 | 79 12. 30 25 6 80 76. Loo-l7 PL mm eyS, 7 78 ati 18 13 26 5 8 78 716 20 Al 26 3 9 80 78 LS IAD) 56 10 80 718 23. 25 27 = 20: 11 ‘80 13 D4 23 37 121 78 \76Shark8s{| 2% 48 32 Y3 76 74 260 ZO AY 14 74 Nee, D7 50 24 14 1 We 70 28 42 35 16 72 70 $1 45 * The atmofpheric temperature was not fet down during thefe days. + Each,trial upon the fea-water was repeated gees or four times, and the fame refults followed. { Caught a fhark, and found the heat in its ftomach, after being fuddenly killed, 88°, Table TEMPERATURE OF THE SEA. ; ! 133 [ Table continued, } Atmo- ~) Table of the fphere. Sea-Water. Lat. S. Long. W. | | temperature of ee eee fue oie ena ie | the fea, Eco 70° | 68° 33° 10 23% 57 70 66 34 20 22 46 70 66 Gono 19 38 68 66 36 2 18 35 63 66 36 3 hee val 68 o+ 35° 56 1 aie 68 6+ 6 47 66 64 36 47 BS 64 62 86 34 41 Kaft / 64 62 39 3 40 i 62 58 20) Pe 6 320 61 | 58 53 7-40 60 58 45 8 40 60 58 36° 30 Merit hit 60 58 7 LE 1S 60 58 30 18 13 60 60 34 10 16 60 60 Bh tee 22. Bo 60 62 10 26. 48 58 64+ 36 54 TO 751 62 66 30 34 5] 64 66 37 39 39 62 64 3 43 21 62 64 20 4a” ZI 62 64 55 43 48 14 64 66 ga WS 49 38 66 66 30 35 51 18 68 68 BT Ga D212 he 70 25 2 31 76 74 PRON 39 78 76 18 52 53 16 78 76 16 25 54 12 SO 78 ioe a te oS 29 78 78 12 41 50. 55 80 78 10 56 49 41 80 78 7 8 49 41 80 80 4 9 50° 32 81z | 80 1 46 52 27 84 81 13 N. 540 2 86 82 Pn 3D 50 59 84 | 82 4 36 56 10 85 82 9 26 60 51 85 §2 9 26 60 5l 85 §2 14 31 64 41 84 82 15 56 66 59 86 §2 i7,. 32 69 40 854 | 84 18 57 42 Arrived in Bombay Harbour. Obfervations T34 ON FLUIDS AS CONDUCTORS OF HEAT, Bx. Ob/ervations upon the Doctrine of Count Rumford refpedting the want of dire@ conduding Power in Fluids with regard to Heat. By Cit. BertHouvet.* The doétrine of Count RUMFORD has publifhed feveral memoirs, by. she knoe which he has endeavoured to prove that liquids and elaftic dudting property fluids are not conduétors of heat, and that they only tranfmit of fiuids deferves caloric by means of the contaét with folid bodies, which is examinatione A . k owing to the motion of their parts; as this property would make a difference between the ftates of a fubftance much °‘ greater than there is occafion to fuppofe in the explanation of the other phenomena; as, befides, this celebrated philofopher’ has fixed the attention on an objeét which had been negleéted, and has drawn applications from it, beneficial in the arts, and in the ufes of life, I think it proper to offer fome doubts on the principles which he has deduced from his obfervations: I fhall, in the firft place, examine whether the faéts on which he relies, cannot admit of a natural explanation from the properties which I have already analyfed, or whether it will be neceflary to have recourfe to particular properties. But I fhall attend only to the confiderations which may ferve to elucidate this difcuffion, without introducing the details it would require, if I were to examine it more fully. Detail of Count The experiments which the author made were performed Rumford’s exe with an apparatus, of which it will be proper to infert a de- periments on c . . e er: ~ . heated fluids. fcription., ‘* He employed a cylindrical glals jar of 4.7 inches in diameter, and 13,8 in height; he put a known quantity of water (about two pounds) into the jar, which was intended to form a cake of ice at the bottom of the veffel. For this purpofe, the jar with the water was put into a frigorific mix- fure of falt and ice, the aétion of which was not long in con- verting the water into a folid difk adhering to the bottom and fides of the jar; the jar was then removed, and plunged into a mixture of ice and water, to the level of the interior cake, which gave it the temperature of melting ice, or of the zero of the common thermometer. Then, after having covered the furface of the ice with a difk of paper,+ hot water was poured * From his Effai de Statique Chemique. + Bibl. Brit. ig | on. ON FLUIDS AS CONDUCTORS OF HEAT, 135 on it, as gently as poffible, to about the quantity of 74 ounces; Detail of Count this water was about eight inches above the furface Ee a tebA difk.” heated fluids. — _ The paper was then removed very gently, and after hav- ing fuffered the water to remain a certain number of minutes in contaét with the ice, it was poured off, and the jar with the ice which it ftill contained immediately weighed; its dif ference from the primitive weight eftablithed the quantity of - ice which had melted while the hot water remained above ati”? ; Having obferved that the motion occafioned by pouring on the hot water produced an effect which was confiderable, and foreign to the communication of heat, the author fucceflively devifed feveral modes of diminifhing it. ‘* He introduced the hot water through a wooden tube, clofed at the bottom and pierced laterally with feveral {mall holes, through which the water iffued upon a wooden difk, alfo pierced like a fieve, and floating on the water as it rofe in the veffel. This difk was re- moved as foon as the water was poured in, and the veffel was covered with a wooden lid, in the centre of which was fuf- pended a thermometer; finally, by previoufly covering the ice. with a ftratum of cold water, about half an inch in thicknefs, in which the perforated wooden difk floated, the author fuc- ceeded in greatly diminifhing the irregularity of the refults.” Befides, thefe precautions, the author feparated from his refults the quantity of ice, which liquefied at the firft infant, and which exceeded that which melted in the fucceeding {paces ‘of time: in thefe different experiments, while that part of the cylinder which contained the ice was kept. conftantly at the temperature of melting ice, the upper part was left in contact with the furrounding air, or furrounded with a bad conduéting fubftance, or plunged into the mixture of water and ice: the ‘water poured on the ice received different temperatures, I ‘make three divifions of the refults of all the experiments: 1ft. Water which was only about four degrees above zero, melted a little more ice in the fame {pace of time than boiling water: 2d. When the upper part of the cylinder. was wrapped in a bad conduéting fubftance, the hot water melted more ice than when it was in contaét with the air: 3d, When the upper part of the cylinder was plunged into the mixture of ice and water, more ice was melted-than when it was left in contaét with the atmofphere at 61° Fahrenheit’s thermometer, . To 1386 ON FLUIDS AS CONDUCTORS OF HEAT. Explanatione To explain thefe obfervations, the properties which we have a ve wet recognized in liquid fubftances, and in elaftic fluids, and from ricated rhe great- which we have inferred the changes which are effected in their $ joe dee. different {tates of combinations, muft be applied to the pheno- 2. Locomotion mena obferved by Rumford. increafes this We have feen, 1ft. that the liquid particles enter fo much efte& in fluids, and ought to be the more rapidly into combination asthey were at a greater feparately con- diftance from faturation, becaufe then the force which folicits ‘nesomee E feet the faturation is greateft; fo that the effets which depend on not followthe the communication of the temperature muft be very weak, ae when the differences between them are but fmall. 2d. Locomotion, which ferves to bring particles together which are at a greater diftance from faturation, accelerates the effeét of the mutual aétion by which its equilibrium is eftablith- ed, fo that it is neceffary to feparate the effeét which depends on this caufe from that which is owing to immediate commu- nication. 3d. Water and fome other fubftances acquire a greater rs cific levity on approaching the term of congelation; whence it follows that the locomotion produced by the variations of tem- perature in other circumftances will be fubjeé to modifications, which muft be allowed for when water and the other liquids which poffefs this property, approach the term of congelation. To apply thefe properties, we mutft alfo take into confider- ation the dire€tion in which the heat is communicated; for the combination of effeéts will be different accordingly_as it is ap- plied to the inferior or fuperior part of a liquid. Locomotion is In order that a ready motion may be eftablifhed between the Sivas fae particles whichare at the bottom of the veffel, and thofe at the perature is fmall, furface, there muft be but little difference between their tem- perature; the particles which are near the ice, and become expanded, will then raife themfelves above thofe which have a temperature barely greater; but if the temperature fhould caufe a great difference between the {pecific gravities, this mo- tion will be much more confined, fo that the ice will remain furrounded with water of its own temperature, or which is very little removed from it. It is evident, therefore, that that part of the effe€t which depends on the motion will be- much lefs, when there is a great difference in the temperatures. ~ The effe& of == But when this diflance in fa@t exifts, the effe@ produced by the heat by a fluid will be the communication of the heat, independently of the motion, | / 4 ee ~ will covering, the heat will be retained, and a greater quantity will ON FLUIDS AS CONDUCTORS OF HEAT. 137 is , : Oe ) : teft wh will vary according to the manner in which'the temperature is Oy a ence of preferved in the liquids. | If the veffel has a non-conduéting temperature is mott favourable to both the be communicated than if it had been allowed to pafs into fur- caufes of its rounding bodies.—But when the difference of the temperature i uae of the liquid is not confiderable, as in the experiment in which experiments res water at 16° was employed, it is more advantageous to aug- quire on ae iam ment the effeét owing to the tranflation of the particles, by paca kauri icg cooling all the cylinder, than to preferve that which is owing to the fimple communication of caloric. It appears to me that this explanation naturally flows from the known properties of fluids, and that Rumford’s obfervations do not lead us to new . indu@tions . It muft be remarked that by feparating the effe€t which took Additional re- we at‘the firft, when a confiderable difference in the tem- mate perature could occafion a quick communication, he only ob- ferved that which was produced when there were but very * flight differences between fucceflive ftrata of the liquid and the ice itfelf: now, when there is but a {mall difference of fatu- ration, either between chemical combinations, or between the temperatures, the equilibrium is eftablifhed very flowly, and it becomes difficult to appreciate. the effects. The experiments which Rumford made by plunging a {mall i owe cylinder of iron, heated to the degree of the ebullition of and heated irone water, into water and mercury ftanding over a {mall piece of ice, without producing its liquefaction, only prove that when two bodies differ but little in their temperature, the equilibri- um is eftablifhed with difficulty; for it muft be obferved that the iron, which had but a little fpecific heat, and is a good con- duétor, muft have loft the greateft part of its heat rapidly, in that part of the liquid which it paffed gently through, and ne- verthelefs have raifed that of the liquid but little, or even that of the mercury, confidering the mafs of it. But in thefe experiments of Rumford I find proofs of the Other faéts to property which he denies to liquids. yaa ig 1ft. In all the experiments which I have quoted, except in duétorse thofe made with the heated cylinder of iron, the liquefaction of the ice took place in a confiderable degree, and each part liquified fuppofes a quantity of heat which would have raifed an equal weight of water from the term of congelation to 75 _ degrees of the centigrade thermometer. 2d. He a es 138 ON FLUIDS AS CONDUCTORS OF HEAT. 2d. He froze the water at the furface of mercury cooled by a frigorific mixture; the temperature of the mercury was there- fore communicated to the water, and the latter yielded its ca- loric to the mercury, to replace that which it loft. If the communication of heat was only the effec of the par- ticles of a liquid, the mercury of a thermometer would fcarcely change its temperature when it had arrived at the freezing pomt ‘of water: in fa@ in feveral of his experiments (Efay7,) Rum- ford fuppofes, that at this degree, the mercury no longer com- municates heat: now a thermometer takes the temperature of neighbouring bodies very rapidly, and indicates it feveral de- grees below. the freezing point of water, and as far as its own congelation; then it conduéts itfelf like the folid bodies, and its dilatations become proportionably fmaller than the preceding. Mereury ¢on- Rumford has proved that the conduéting power of mercury a ice is to'that of water as 1000 to 313. denfer, hes lefs This effe€t of the mercury, which takes the temperature of ee the fyftem in which it is placed more rapidly than the water, ; although it has a much greater f{pecific gravity, and is much lefs dilatable by the fame degrees of heat, and confequently the heat will caufe much lefs locomotion in its particles than in thofe of water; this effea I fay, proves that the changes of tempe- ature do not depend on the immediate communication and the changes of {pecific gravity which produces the approximation of the particles of unequal temperatures, but alfo on the better or worfe conduéting property of each fubftance. Rumford neg- 3d. Rumford paid no attention to the radiant caloric, nor hese the radiant 4:4 he make any allowance for it; neverthelefs the communi- cation of heat eftablifhed by its means between folid bodies and liquids, through the gafes, cannot be doubted, and it may be remarked that when he brought a heated bullet near to ice and tallow, a conimunication of heat took place which melted the furface of both, without it being poffible to attribute this communication toa circulation fuch as he thinks is neceflary. Experiments of The ingenious experiments of Rumford have employed the hes talents of feveral philofophers, who have already proved that the principles to which they led were not conformable to the true refults of obfervation. Nicholfon found Nicholfon, in conjunction with Piet, made fome experi- abel a ments by which he proved, that, on heating a liquid at the through a fluid. furface, by the fuperpofition of a body, the heat penetrated, and 2 . | ON FLUIDS AS CONDUCTORS OF HEAT. 139 and raifed a thermometer placed at the bottom of the liquid : to avoid communication by the fides of the veflel, a bad con- duéting fubflance was made choice of, and he afcertained, by means of a thermometer placed in the fame liquid near the fide of the vetlel, that no current was eftablifhed which differed in the temperature : finally, the motion of the bubbles which were difengaged, and the other appearances of the liquid, convinced him that currents were not formed. ” In thefe experiments * it was proved, that liquids were —and that oil different in their conduéting faculty; the penetration of the i a heat from the top to the bottom, was five times flower in oil mercury. than in mercury. . Rumford fuppofed that the flighteft changes of fpecific gravity were accompanied by a locomotion, which produced a current, and he endeavoured to render it vifible, by ex- pofing an alkaline liquor, in which were fulpended very {mall fragments of amber, which he found had the fame fpecific gravity as the liquid, to a change of temperature: but Thom- Thomfon found fon has fhown +, that the motions obferved in thefe moleculz ee oe were illufory, and that, in thefe variations of temperature, not prove any which are gradual, they appear to be owing only to the dif Currents in the ference of f{pecific gravity which they acquire, and to the ad- ae herence of air-bubbles, fo that fome of thefe mcleculz move in contrary direGtions, and run againft each other without following the direétion of the currents, he has alfo fhown that thefe floating corpulcules might receive different motions while the ftrata of the liquid maintained a perteét tranquillity: he _ put water, tinged blue by juice of red cabbage intoa glafs vef- —the floating fel; he afterwards poured clear water on it with great precau- oe rofe and tion, by means of a tube with a capillary extremity; thus he seat oe kept the two liquids feparate and diflin@; he then heated the of different veffel gently at the bottom: it is manitfeft that if a current jae ee been eftablifhed, it would have been marked by the coloured liquid, but the feparation of the two liquids was preferved un- confufed ; moreover the corpufcules put into the firft liquid _moved upwards and downwards, and croffed the line of fepa- * Bibl. Brit. Tom, XVIII. or Philofophic Journal, Quarto faries. V. 197. + Nicholfon’s Journal, Oégtavo, for Feb. 1802. See alfo a me-_ moir by this philofopher, in the Journal for March, 1801, contain- ing the earlieft experimental examination of the Count’s doégtrine, eS ile | ration 140 Murray made ON FLUIDS AS CONDUCTORS OF HEAT. * ration without producing the mixture of the two fluids, fo that | their various motions were not the effeGt of a current which carried them with it, and neverthelefs, the heat was communi- | cated to all the liquid. The propagation of the heat, and the | agitation of corpufcules, which have nearly the fame fpecific | gravity, may therefore take place, independently of thecircu- latory motion, which is only eftablifhed when there isa differ- 9 -ence of temperature of a certain intenfity between the differ- ent ftrata of a fluid. Murray has oppofed Rumford’s opinion with experiments experiments in flill more dire@t, and not lefs conclufive; * he placed the bulb. a veffel of ice, containing a of a thermometer in acylinder of ice, which he filled alter- fluid. The heat nately with oiland mercury; he afterwards brought a heated paffed down- wards, —and mercury body near the furface of the liquid; the thermometer rofe fe- veral degrees in both experiments; but the heat could not have been conveyed by the fides of the ice whofe furface would have abforbed and liquefied; no current was eftablifhed, for the molecule of the liquid having become lighter, could not take a contrary direction, and the author avoided ufing water, which contraéts en pafling from the degree of congelation to a temperature a little more railed: the heat muft therefore have _ been communicated to the bulb of the thermometer without the eftablifhment of fuch a current as is fuppofed to be requifite ; and that which ferved to dilate it was only the excefs of what had liquefied part of the ice. wa The obfervations of Murray prove at the fame time that conduéted better mercury is a much more effective conduétor of heat than oil, than oil. for the elevation of the thermometer was manifefted by-its in- termedium in a much fhorter time, and more ice was liquefied. * Ann. de Chim. Floreal, An. X. or Philof. Journal, Otavo, T 165. 241. The experiments of Thcmfon and Murray, originally appeared in our Journal, and thofe of Count Rumford are alfo given, for which fee the Indexes. ; (To be continued.) On DIFFICULTY OF OBTAINING ALUMINE. 141 XXII. On the Difficulty of obtaining Alumine in a State of Purity. By R. 6 i To Mr. NICHOLSON... SIR, Your Journal being open to every difquifition which may contribute to the progrefs of fcience, it may not be deemed, impertinent to afk you, or fome of your correfpondents, to point out the beft method of preparing pure alumine. You may, probably, refer me to our modern authors on A!umine ob- chemiftry, but I aver that the methods therein recommended Ba oh do not anfwer the purpofe. For if a faturated folution of lutions of alum alum of commerce, be decompofed by a like faturated olution 7"4 ™*@lis of a carbonated alkali, the alumine obtained is harfh to the touch, rather {pungy, and ftrongly adheres to the tongue. This earth, although wafhed as often as you pleafe, always appears to con- tain acid, and is ‘ reddens the blue juice of the flowers of mallow, as well as gibi. of other delicate vegetable blues. It, may be wholly dif- folved in about 100 parts of boiling water: and the folution . becomes very turbid by muriate of barytes. If, on the other hand, a dilute folution of alum be decom- Dilute folutions pofed by another of alkali, a quite different produé will be petite ok obtained. The alumine produced, on being deficcated is not ance, porous, but fplits into pieces like ftarch ; and has, before it is nearly dry, a certain degree of tranfparency ; it breaks with a {mooth and nearly conchoidal fracture ; it does not adhere to _ the tongue like the former, and has no earthy appearance. This, like the former, cannot be freed from the adhering acid, likewife acid. Tt alfo changes fine vegetable blues to red, although ever fo much wafhed. What is the reafon of this? Is there no method of forcing this earth from the adhering acid? or is it perhaps a characteriftic of the earth itfelf, to redden vegetable blues. If you will pleafe to anfwer this queftion, or point out a better method for procuring this earth pure, you will. much oblige, ~ Camden-Town, Sir, Your conflant reader, - May 28, 1804. Ker REPLY. THIS letter having arrived fo late in the month, I can only for the prefent offer it to my other ccrrefpondents. SCIENTIFIC New earth. SCIENTIFIC NEWS. SCIENTIFIC NEWS. oe New Earth. A NEW earth has been difcovered by Profeffor Klaproth of Berlin, in an ore which was hitherto fuppofed to contain tungften, to which he has given the name of ochroit earth, the mineral which contains it he has called ochroit, (ocliroites.) This earth feems to form the conneéting link between the earths and the metallic oxides. Like yttria, it produces a reddifh coloured falt with fulphuric acid; and is precipitable by all the pruffiates; but it is diftinguifhed from yttria by not forming fweet falts, and by not being (at leaft much lefs) foluble in carbonate of ammonia, and by acquiring when ignited, a light brown colour. This earth farther differs from yttria, by not being foluble either by borax nor by phofphates, with which yttria fufes into a colourlefs pellucid bead. Its — other charaCteriftics, and’ method of obtaining will be given ; in our next Journal. a Seem Ao, Subertc Acid from Paper*, i iZ BRUGNATELLI has obferved, that when nitric acid _ is made to act upon paper, a large quantity of fuberic acid, — mixt with oxalic acid, is obtained. This proves that Fourcroy - was right, in placing cork among the immediate principles — of vegetables, EE Eafy and expeditious Method of preparing Copal Varnifh +. DEMMENIE, an ingenious glafs blower, has noticed that the folution of copal may eafily be effeGted, by expofing it to the vapours of alcohol or oil of turpentine. For that purpofe — an alembic may be filled } with either of thefe fluids, and fome pieces of copal fuffered to be fufpended by threads in it, — over the furface of the fluid. After having made the alcohol _ or oil of turpentine to boil, the copal becomes liquefied, — drops into the fluid and becomes diffolved. When no farther — * Gehlen’s Yournal of Chemiftry: Vol. I. p. 3. page 340. + Ibidem. folution — SCIENTIFIC NEWS. 243 folution takes place, the whole is fuffered to cool, and the folution of copal is decanted from the undiffolved.part. The varnifh has no more colour than the copal itfelf. EE Large Piece of Amber *. A PIECE of amber weighing 13lb.7 oz. 9fcr. and meafur- Large fpecimen ing 3182 cubic inches, has lately been found at Schlapacken, ee near Gumbinnen and Infterburg in Germany, which is the largeft mafs of amber hitherto found. Its colour is a pale yellow, interfeéted with feveral lines. Its value is eftimated _ at about 40,000 dollars. tt nll Fluoric Ether +. 150z. Previoufly ignited and pulverized fluate of lime, were introduced into a retort containing 10oz, of ' highly re@tified alcohol, and an equal quantity of fulphuric acid of 1,860 fpec. grav. and the mixture diftilled to drynefs. During the diftillation, a large quantity of gas was evolved, which burnt with a beautiful blue flame, and diffufed an odour refembling phofphorated hydrogen. During the combutftion of this gas, vapours of fluoric acid were precipitated. The produét which had been obtained during the diftillation was again diftilled to. one.half, and the produé which paffed over, was. poured into a vial containing water. No heat was pro- duced, nor did the two fluids mix. It was therefore ether, - But as its tafte was four, I added to’it a folution of potath ; this inftantly feparated a confiderable quantity of filex, and the whole became’ converted into a gelatinous mafs. The whole mafs, on being again diftilled, yielded pure fluoric ether. It greatly refembled fulphuric ether; its fpecific gravity was 0,720; it burnt with a blue flame; its tafte was _ bitter, and greatly refembling bitter almonds. ee New Method of preparing Nitric Ether. By BRuGNATELLY {, Nitric ether. INTRODUCE into a tubulated retort, one ounce of fugar, and pour over it two ounces of highly concentrated alcohol. Adapt to the retort a capacious receiver furrounded with # Ibids + Ibid, t Ibid. cloth 14:4: Afcenfion of fulphurated hy- drogen gas. SCIENTIFIC NEWS- cloth dipt into water; and fecure the junétures of the veffels — by furrounding them with flips of paper only. Having done this pourthrough thetubulure of the retort 30z. of concentrated nitrous acid ; a violent aétion takes place, the fugar becomes diffolved, and the alcohol converted into ether, paffes over into the receiver; its quantity is nearly equal. to the alcohol employed. Accenfion of Sulphuretted Hidrogen Gas, by the Affufion of Nitrous Acid. By Profefor LichTENBERG*, ATTEMPTING to illuftrate the decompoiition of fale a phuretted hydrogen gas, I filled a bottle with it, capable of P holding about 180z. of water. Having done this, I poured into it at once, 3 of an ounce of nitrous acid; a hiffing noife took place, and tie red vapour was difenpenesks which in order not to moleft my auditors, I confined in the bottle, by « corking it. No fooner had this been accomplifhed, the mix- ture exploded with a loud report, accompanied with a blue flamet+. The pieces of glafs were thrown to a confiderable diflance, the larger ones were covered with fulphur, aa * Ibid. rel Oh A at + For the fuccefs of this experiment, it feems to me to fees : favy that the gas muft be obtained by decompofing water by means of falphuret of iron and an acid; for it always failedin myhands, if an earthy or alkaline fulphuret ‘hed been made ufe of sata ich du&tion of it. F, A. RGUUZERRUABERAULCOMURT OLS KOUEEUDI CEI TmII LUM i Cl i m ii il ii ea sous er A A iH HH cata moe et HINA A la ee 10 A A Mu ne lid te ‘i ‘cic pce men nll ‘ah I oS T= in | iN ni nh Be aa ci = uatiuitl MUTI CHUNSGISROSSASPANEGRSUPASOSEDROGRRGSECRCAGAUGAUAE RRA SUAAROUESSILUASREDHODESLAGUSGHUMERSAGASGSEDADASDEOSE! SU BVQESTSSSBOUAIORACRANRNNESI — a basta MA ee | i | SS SS — = == SSS SS Philos. Journal. Vol. VAT Pt. FREE we A Bramahs VOM > Oe: —«sit It ve es. — il | | u ee “a | a : _LPhilos. Jownal. Vol. VL FA, VIpl4. Alle Clg Spare : | | | i || y j | (: y - i | | | aa » | q | | Geran Se Spo LALUA N | ee a . Drawn by Blunt. Engraved by Mutiow. Philos. Journah Vol VM. PUVIT p44. CIHrccenl woolen esos) . es = . wed wn’ C Vy fil and th Mo tt fed BL el eee te On ae of the Sirk Onfirc OTN Mise WAN HIM | Gey =| =| rile PO ay aR | : ; rr « 2 _ Philos. Journal. Vol. VIM, PU. VUE p LAA. e me : gees ¢ Za thane oe Cc. A WLWEC Lifer bea. ! | Bnanaved by Mutlow, Drawn by Blunt. ‘ A JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, AND PIPE ARTS. pe fuk, NB0d, ARTICLE I. # On the fuppofed Chemical Affinity of the Elements of Common Airs with Remarks on Dr. Thomfon’s Obfervations of that Subject. dna Letter fron Mr. ). Dauton. To Mr. NICHOLSON. SIR, In a former letter, inferted in your Journal (new feries, vol. eon re< III, page 267) I endeavoured to thew the abfurdity of the no- ohio ot his tion of atmofpherical air being a chemical compound of azotic mofpheric air is and oxigenous gafes. Befides the difficulty, or rather impoffi- Preps: pis jo bility on the one hand of conceiving how two elementary par- ticles, conftantly repelling each other, fhould notwithftanding be held together by a principle of cohefion or chemical affinity ; or on the other hand, fuppofing the two atoms to combine, and form one centre of repulfion, how atmofpheric air fhould _ differ from nitrous gas, &c. There are a variety of faéts which oppofe the doétrine fo forcibly that I have for fome time won- _ dered on what grounds thofe who are ftill its adherents de- fended it. Dr. Thomfon, in the fecond edition of his che- Dr. Thomfon’s mifty, vol. III. page 31 6, after reviewing the opinions of dif- rae a ferent philofophers on this head, and amongft others my own, doétrine. concludes that air isa chemical compound; he affigns the four» following reafons for the conclufion, which, from his extenfive Vor. VIUI.—Jury, 1804. ye ace 146 SUPPOSED CHEMICAL AFFINITY OF acquaintance with authorities, may fairly, it is prefumed, be deemed the moft cogent that have been offered on that fide of the queftion. It is the objeét of this communication to fhew sl infufficiency. x. The conftant . The conftant proportion of azot And oxigen in the atmo- proportion of ey is confidered as an argument for their Aig held by affi- ae be nity. So indeed it may ; but it is equally in favour of my hy- regulated by af- pothefis, and therefore nothing tending to decide the queftion ee eas can be obtained from it. For, let part of the oxigen be ab- of the abundant ftraéted any where from the atmofphere; then the azot may be’ 648, fuppofed to attraét the oxigen from the vicinity, and thus the equilibrium be reftored: but it is certainly equally fatisfa&tory to fuppofe that the oxigen in the vicinity, meeting, with a lefs repulfive power from the deficient quarter, nothing’prevents its diffufion into that quarter but the azot previoufly there, which, by hypothefis, can only retard, but by no means prevent ~~but thismay the effeét. Thus then, whether the azot attra@ the oxigen, or chant Ys the oxigen reped itfelf, the effeét is precifely the fame. From cribed to dimi- this fa& fimply, it is impoffible therefore to decide the merits ee ee of either theory; but if it be found that any one gas diffufes eee che i(felf in any other, with nearly the fame celerity, it willbe a ec prefumption in favout of my hypothefis; if otherwife, it may be urged that the quicker diffufion is owing to the ftronger afli- nity. [have made a great number of experiments on this head, but could not find any remarkable difference in the time and circumftances of diffufion of the fame gas. 2.Humboldtand 2. It is faid the experiments of Morozzo and Humboldt fhew Morozzo's €x- that air polleffes different properties from a mere mixture of ils periments 5 that i rea a mere mixture {wo component parts. I do not credit the experiments,— ee hate Humboldt finds a variable quantity of oxigen, from 25 to 30, airt—-not cree OF more per cent. in the air; whereas others who are more dited. accurate, find but 21, or at moft 22, and that conflant. It is no wonder then, if hémix 28 oxigen and 72 azot, that the mixture diminifhes nitrous gas more than air, and fupports combutftion and animal life for a longer time. 3-Differentcom- 3, Different combutftibles are apie of abforbing diffaenk pp hie: portions of oxigen from a given quantity of air, Phofphorus tities of oxigen 22 percent. Sulphur, 8, &c.—The only inferences I draw "a common from thefe facts are, that pho{phorus will burn in oxigen of any denfity, that fulphur will not burn in oxigen unlefs it be of 4, of atmolpheric denfity or more, The difference in the. pheno-) 3 — . anena- \ THE ELEMENTS OF COMMON .AIR, 147 tena of combuftion in air, and in oxigen is not to be afcribed Afcribed merely tothe combination of azot and oxigen, but to the lefs denfity Oe of the latter, (2) of what a pure denied of the fame 88 igen in which would be. et an incidental but imperfeé trial I made, in ue ceafe to conjunétion with Mr. Davy laft winter, I have no doubt but ii iron wire would burn in common air of five times the denfity with brilliancy as in an atmofphere of pure oxigen of common denfity. At any rate it is notorious that as the denfity of com- mon airis increafed, combuftion in it becomes more vigorous. Though I have never attempted combuftion in an atmofphere Propofed expe- of pure oxigen of + the common denfity, I can fearcely doubt Timea Se that the appearancees would be much the fame as in the open air. It is probable therefore that the faéts under this head, if duly inveftigated, would turn out in favour of the hypothels of air being a mixture. 4. * A gas no way diftinguifhable from common air fre- 4. Gas refem- quently Bes is appearance during the preparation of nitric Pp oad pr a acid; and Mr. Davy decompofed nitrous oxide, by pafling it preparing nitrous through a red hot tube, and converted it into nitric acid and a 4¢-4# gas, which poffefled the properties of common air; now if air were a mere mixture, it is infinitely improbable that its two conftituent parts fhould be evolved during fuch proceffes ex- aétly in the proportion that exifts in common air.” —Granted.; but as the force of this argument refts upon the exa@ propor- tion of oxigen and azot in the gafes fo evolved, that is, upon their being conftituted always of 21 percent. oxigen, and 79 -azot, the facts fhould be made out accordingly. Dr. Priefiley Anfwer. The is the only one I know of, who has particularly examined the Riese, coon gas produced in the preparation of nitric acid, and he found it postion of partsy ~ to have much more oxigen than commonair. Mr. Davy in his pr ii analyfis of nitrous oxide, found the gas analogous to atmo- {pheric air always to contain /efs oxigen, though it was nearly of the atmofpheric ftandard. The quick afcent of hidrogen and the defcent of carbonic The ftatical acid, have been objeéted to my, hypothefis as faéts that prove on — the operation of the laws. of {pecific gravities on elaftic fluids. fords no proof - No doubt can exift that a portion of elaftic fluid completely Byers infulated, asa balloon, ora bubble of. carbonic acid or hidro- gi¢ygon, _gen, furrounded by a film of water, is fubjeét to the laws of. gravitation, and rifes or falls in elaftic fluids on the fame prin- L 2 ciple 148 SUPPOSED CHEMICAL AFFINITY OF ciple as it rifes in water; the fame muft be allowed when @ veffel, containing a confiderable portion of elaftic fluid, is fud- denly expofed at fome furface to the atmofphere; in this cafe, the fluids mujt operate upon each other for a few moments in a colleéted capacity, as in elaftic bodies; becaufe the diffufive or repulfive force by which they conftantly tend to difperfion, is comparatively flow in producing the ultimate effeét, being in this refpeét exaétly fimilar to chemical affinity, the operation gradually diminifhing as the effeét draws towards a conclufion. For the feparate Nothing more therefore can be inferred from the faéts above- maffes arecare mentioned, than that gravity overpowers, and for a moment ried by their : f F relative gravity obliterates the effeét of that caufe which in other cafes flowly more fpeedily — produces the difperfion of the fluid, whether it be attraétion, than the diffue 3 fioncantake a8 commonly fuppofed, or repulfion, as I fuppofe. Chemical Place. philofophers have not enquired fufficiently into the effects of expofing gafes in different circumftances to the atmofphere ; all that we are ufually told is, that a jar filled with hidrogen and uncovered, lofes its gas ina few feconds; but if inverted, it remains nearly pure for a confiderable time, &c. I find that a cylindric jar of 7 inches depth and 2} diameter, being filled with hidrogen, and inverted, lofes more than half of its gas in two minutes, and there is fo little left as fcarcely to explode in But the diffufion five minutes. If atube, 12 inches long and } inch diameter, aig ts wun be filled with hidrogen, and expofed in like manner to the at- taught. mofphere, it will lofe half its gas in five minutes, and that the fame, whether it be held up or down or horizontal. Here we fee effects that cannot be accounted for by gravity, that are produced in oppofition to its agency, and where indeed it is almoft obliterated by the ation of fome more powerful caufe. Let the advocates for the atmofphere being a chemical com- pound attend to fuch faéts as thefe, and they will foon find themfelves reduced to acknowledge that all ga/es have the fume affinity for one another, a pofition which their doétrine ulti- ‘The facts, if mately tends to eftablifh. Indeed it is the fame with regard pose yt to air and vapour, of water, ether, or of any other fluid; that that itis the 18, all kinds of gas or mixtures of gafes, have the fame affinity rag for the fame vapour, and even a torricellian vacuum pofleffes andevenbe Jult the fame affinity as any of them, judging from the quantity tween a gas and evaporated, and force of the vapour in a given volume. If a vacuum. . : any one doubt it, he may eafily fatisfy himfelf by throwing up a drop THE ELEMENTS OF COMMON -AER.: 149 a drop or two of ether into the vacuum of a common barome- ter; if the temperature be 68°, the mercury will fall 15 inches nearly; at the fame time, if ether be admitted toa given bulk of any kind of gas, fubjeé to the preffure of the atmofphere, the volume will be doubled, clearly fhewing that the elaftic vapour from the ether is the fame in both cafes, namely, an independent fluid of 15 inches force. [ cannot difmifs this fubje@ without obferving, in juftice to Water does not Dr. ‘Thon:fun, that he has entered more clearly into my views aitiolve My. of thefe fubje&ts than any other of our own country who has animadverted upon them. There are certain principles, how- ? ever, which he, with moft chemifts of the prefent day, em= . braces, which ate, according to my experience, decidedly _ erroneous, One of thefe is, that water diffolves uir. An exe cellent paper of Mr. W. Henry, on the abforption of gales by water, in the Philof. Tranfaétions for 1803, has fhewn us fufs ficiently in what light we fhould view the fuppofed folution of air in water. Certainly air that is retained in water by me- chanical force, and which always efcapes when that force is withdrawn, cannot with any propriety be faid to be held by chemical affinity. Dr. Thomfon has been mifinformed refpe€&ting my opinions The author does on the expanfion of liquids. In vol. i. page 343, he gives it 5° prelinr i as my fuggeftion, that all liquids expand the fame quantity all liquids by from their freezing to their boiling temperatures. I never en- ely g tertained fuch an opinion ; and it is certainly erroneous. | My lation and boile idea is, that pure and homogeneous liquids, fuch as water and ing fhe er mercury, expand according to the fquare of the temperatures obi Bhs 4 from the points at which they congeal; but Ihave not yet found we the fquare a law to regulate the relative expanfions of thefe and other jure trom hs liquids. freezing points Iam your’s, &c. laos DALTON. Manchefter, _ June 16, 1804. Easy 150. OF SQUARES AND CUBES. il. Eafy Methods of completing the Tables of Squares and Cubes. In a Letter from H..G, i) To Mr. NICHOLSON, SIR, Computation of lv the laft number of your Journal, Mr. Councer’s extenfive fquares : table of {quares is ftated to be deficient from No. 28261 to 29061. ‘This deficiency may very eafily be filled up by this tule. To the fquare of any given root add twice that root -- 1; the produét will be the fquare of the next root. OF cubes; The table of one half the cubes in Mr. Councer’s table, may half the feries;_ eafily be made, examined, and added to, by the following rule: Multiply the cube of any given root by 8; the produét will be the cube of twice the next root. : the other half. The other half of the cubes in the fame table, and alfo all thofe already found as above, may eafily be found from any two cubes and their roots in fucceflion being given. Thus: From the given cube of the largett of the given roots, fubtraét the given cube of the next lefs given root; to the remainder add fix times the largeft given root, and alfo the given cube of the largeft given root ; the fum will be the cube required; as will appear from the following example: , Roots, Cubes. ae 9999—-A—= 999700029999 ? Required the cube ') D==10000==B=1000000000000 { of the root 10001. B a prasad Mocs 299970001 Remainder, 6D— 60000 } Six times thelargeft given root. 8.5 *teais _. § Cube required of B4+C-+6 D=1000300030001= } Nia oot nae Dam, ita Your moft humble fervant, Eaft Smithfield. oe Seah Crs Problem FROBLEMS IN SPHEROIDAL TRIANGLES, 1S] iit. Problems in Spheroidal Triangles. By Penrcrinus Pro TUS. To Mr. NICHOLSON. SIR, ‘Tue folution of the problem relating to the figure of the New problems earth, in my firft letter*, led to fome new properties of {phero- enue: idal triangles, from w thieh I hall endeavour, in this, to deduce ; a few rules, that may be applied with fuccefs m trigonometri- cal furveys. It will be found that, though the general formula be complex, yet, in the cafes that occur in practice, they ad- mit of being fufficiently fimplified ; for not only may the terms involving the fecond and higher powers of the compreftion, but alfo frequently the differences between the longitudes and ge hy es of the ftations, be rejected. ‘ Having given the latitudes of two places on the furface Prob. I. Given of th earth, and the length of the ftraight line or chord joining be ia them, it is required to find their difference of longitude ?” Required diff. Let a, ? be the latitudes of the two places, D their diftance !o"sit» by ping tt : c in fathoms, a the radius of the equator in fathoms, —=93 the a compreffion at the poles, d fuch that fin 1d=—, and »’ the difference of longitudes of two places, whofe latitudes are A, ?, and diftance d on the fphere. Then by the formula, page 16,* the true difference of longitude» is equal to o/+ Qx —=0'+Q 3, if we reject the higher powers of 9, in which + Pie: __2(fin a—fin ?)?—2 fin 3 d* (fin A?-+-fin x), col. A col. @ fin 0’ -Now becanfe in trigonometrical furveys, d, »’, and (A—9) 2(findX—fin9)? _ are fmall, we may take Srntor bine *¥ Journal for May. + There are fome typographical and other errors in the paper referred to, which I have taken notice of at the end of this letter. ae Se 8 cof, . 152 PROBLEMS IN SPHEROIDAL TRIANGLESa« airy re - TE SR AO EME SR RN) ‘Say ps ee —, and cof, A col. ? fin o” 2 fin 3 d? (fina*+fin $7) = e a t = oat al fae 4 tang. a ange ex d , 2 tang. a tang. ? fin 3 dx— without any fenfible error, which value fubftituted in the for- mula w='+Q 4, will give the true difference of longitude re. quired. © When the meafured chord is perpendicular to the meridian, , whence we find, d D ° . /— = % is nearly equal to ms and confequently » cof. Aa cof. ar”. D D aes S 3 43 me wie anda er (1 b] fin *), OF Pa (ape fina)’ but ae fin A” is equal to the radius of curvature of the perpendi- _ cular to the meridian, in the latitude A=AM< in the figure (Journal for May), which put = R, and there refults o= a which’ correfponds exaully with one © of Legendre’ s theorems; (Mem. Ach: 17: 87). _ Example, Let a=50° 44’ 23,71, the latitude of Beachy Head, 9 = 50°. 37’ 7”,31, the latitude of Dunnofe, D = 56566,57 fathoms, and d= 3496740. Then becaufe fin 2 d= D = d is=— nearly =3336",73, w’=1° 27" 0"",65, and ww! —3105",74 35 “in whicls-ifwe fuppofe —— 559° We fhall have’ ea? 26! 47”, 98. ; tok tee %. ‘ Having PROBLEMS IN SPHEROIDAL FRIANGLES. 158 2. * Having given the latitude of a place, and its longitude Prob. I. Given and diftance from another place, it is required to find the other eligi latitude »” tance from an« Let a be the api the required latitude ; D the meas 206" Pe. fured diftance, d=—, w the difference of longitude, and % — the latitude on the {phere found from A, #, d. Then by fphe- rics cof. 4 cof. % cof. w+-fin A fin %=cof. d, whence, when d, », and A—9 are f{mall, there refults A—?’ => ,/ (d*—cof. a cof. ¢. w?)=+ 4/(d* —»* cof. A*) nearly. But by the theorem, page 16, if ?=9’+-z, we find int in which the variable 2 (fin A— fin 9’)? —2 d? (fin A? +-fin on awa sim cof. A fin % oi wo —{in Acol, 9’ % d* (fina? +fin 9?) —2 cof. (): . (A= 9’) * 2 cof. A fin 9! fin ¥ #’* +4in (A—9’) 2 d? (fin A*+-fin 9’7)—2 cof. (= ~+*): (A—’)* a= cof. a fin 9’ fin 2 w x w’+(A— 9’) Now when 4 and are nearly equal, this formula becomes, pe 25007)— 2 cole. r®.(rA = G')* Q ~ cof. a fin % fin 2e+(A—%) fin a? d* — 2 cof. 4? (A — 9’)? sg A fin aA fin Fu. w+-(A— 4’) ; ‘ Having given the latitude a, the horizontal angle «, Prob. III. re bs diftance D, it is required to find the difference of lon- gre lat, e Orize 3 OF gitude?? — angle and dif- Let > be the latitude, and « the longitude of the place re- ee To find di 2 JONEe quired ; with the latitudes a, ?, and diftance d=, on the fphere, to find the difference of longitude w’, and the horizontal angle e/ ata. | / 2, Then will fin «’ = pa dab of w= an 7? but by firft col. ? d* 2(a—o)? : qneftion ww’ —3 4 tang. a tang. om x= = a ee } jae pat 5 he cof, = =" Q: =. $1 ( “fin @& 2 cof. 92 scat : ve d d fin & oe! fina? ax oe ane’, col & Q “(BS - 2cof. a2 or) — d* fin a t. | Now. wherefore unt Prob. IV. Given two Jats. and diff. long. To find horiz. angles. becaufe ' pROBLEMS IN SPHRROIDAL TRIANGLES.” a ahaa Now by fpherics (>) is = cof, a’? feré, and fin @ = Oe : x fine—2 fine’? cof. a cof, x. .o, by theorem, page 175 or — i y == cof, A cotang. « feré, the fin «is = fin a— WwW ° fin & cof, #’? cof, A240; confequently # is = a a ti qin, A pte RAs ate a2 cof. cee col. @ “fin o? fines From the theorem fin «= fin « — 2 fine’ cof, a’ cof, a*. 6, it is manifefl that «is nearly equal to «’+- fin 2a" cof. a4. 3. When is nearly equal to a right angle, we have » = om ef 1-3 fin A? ye Pua - = col. ? J Keol.@ of Legendre’s theorems. 4. ‘ Having given the latitudes of two places, and their diflerence of longitude, it is required to find the horizontal angles ?? Let a, @ be the latitudes of two places, w their difference of longitude, and #, @ the horizontal ,angles at 4, ¢ refpe@iively © ; which correfponds with one on the fpheroid; alfo «, 6 the correfponding angles on the ~~ iphere, which may be found from the data by the rules of (phe- rical trigonometry. Then by the theorem, page 17, if we put, ; cof. aa fin ?—fina on = 9 fin a2 x cof. o* fin w cof. 2 cof mca x a feré, M = 2 fin «’?x col, D ] N=M. Sn (fin a-+ fin @) -+{ -+ cotang. «’ M*, and x N'=M. nee % (fina + fin ¢) f + cotang. B’ M?, we fall have ez a! Mé+N 2, and 8 =#’—Md + N’9?, Example. . Let a = 3496740, b= 3477210, A= 49°.40’, O50 ie" sy Peyes 30’... (See.the Account of the Trigononie-. trical Survey, &c. Vol. 1, Page 158). Then the two colati- tudes, and tbe included apgle 30’, will give tie fpherical angles a’, B', 43° 51” 48”,3, and 135° 45! 16”,2 refpedively. The remaining part of the calculation i is aS follows : a 2 fin PROBLEMS’ IN SPHEROIDAL TRIANGLES. 155 @ fin a!? - Log, 9.98242 - Sin a (fina-+-fin 9)—2 0.665036 | Cof. a - - Log. 9.81106 - - Cotang. a’.M - - - 0.432644 of, ——. a Log. 9.80957 - - Cotang. 6’. M - - - 0.426906 —— Sec. a - - Log. 0.19193 Q—a- = - Log. 1.30103 N - Log. 9.65937 — N’ Log. 9.65937 wcour. - Log. 8.52288 206264",8 - Log. 5.31443 - 5? - Log. 5.49408 M - - - - Log. 9.61889 - 206264”,8 Log. 5.31443 M"d* . Log. 0.46788 — 2,937 9--- - - Log.7.74704 | M’2- - - Log. 2.68036 - 479”,025 : | +2 ,937 481”,962 = 8! 1”,962 = a—a'’ — fp — Therefore «= 43° 59’ 50”,262, and P= 135° 37’ 147,238. Mr. Dalby makes «= 43 59 51 , 55, andB=135 37 12, 95. I haye already remarked, that the fum of the horizontal To afcertain the angles on the {phere and {pheroid are very nearly equal, and Pigendit |g that they would be perfeétly fo, if we were permitted to reject that the fam of the terms of the formule involving the powers of 3 higher than © ae horiz. angles the {phere the firft. We fhall now, by retaining the fquare of 8, afcertain.s ee reer aie the probable error of this theorem. nearly equal. We have then by the formula, « + P= w+ @’-(N --N’) 32, j fin («+ 6’) M 77 Dik rid LR OL ci Now N-+N’is equal to M { fina fin 0? -} fin a! fin I | 2 fin (2/ LG’ =—M (fin A — fin 0). | find — fin decir ate but in @ all the cafes that occur in praétice, 4 and @ are nearly equal, and the fum of @’, 6! differs little from two right angles, where- fin (a! M fore the fin ~? — fin 9”, an bate (nfl Pain muft be fmall, and fin «’ fin B the fum of thefe is not only to be multiplied by M, which is So that (N + alfo fmall, but by a, which is about é 90000 N’) 22 is dtehntte’ and therefore # + 8 —«’ + f’. : | When ? is nearly equal | toa, the formula may be confider- ably It is almoft rie goroufly exact, Determination of the eccentri- city at place of obf. TROBLEMS IN SPHEROIDAL TRIANGLES. ably fimplified. For then M= 2 fin @’? cof. % x ia i and ow’ N=M (2 fin a? mT ee a M?; and if « = 90° feré, Mis —2 cof. abe , and N= M (2 fina? —¢ The particular ftates of the data, when the term involving the fecond power of 3 is rigoroufly equal to nothing, may be thus determined : In the firft place, if 3=zo, or the eccentricity of the {phe- roid be infinitely fmall, «, ’, and B, 6’, are exaétly equal to each other. Secondly, when M = 0, N is =o, but M is==o when =A, or the fine «’= 0, that is when the triangle is Fateh: or the dire€tions of the places due north or fouth of each other. It appears then that this property of {pheroidal triangles, firft advanced by Mr. Dalby, and objeéted to by Mr. Playfair, isalmoft rigoroufly exaét; and it might eafily be fhewn, that its appli- cation will never occafion any material error, even in the moft unfavourable cafe that can be propofed, And it is not merely an elegant and curious theorem, but is highly valuable, as af- fording a method of determining the longitudes of places from terreftrial meafurements, almoft independent of all hypothefis. For whether the earth be an exaé ellipfoid or not, any {mall portion of | its furface may certainly, without error, be con- fidered as pertaining to one of fmall eccentricity, * which fuppofition is all that is neceflary for demonftrating the theorem. Our folution alfo affords an eafy method of determining the eccentricity at the place of obfervation. For if we have the latitudes and difference of longitude given, we thall alfo have the horizontal angles on the fphere. But from obfervations of the pole ftar, we may find the horizontal angles on the {pheroid, and confequently the difference between them; but this differ- ence is equal to a certain funétion of ¢ in our folution, whence we fhall have an equation, from which 3 may be determined. Thus if « be the obferved horizontal angle on the fpheroid, and e' the computed one on the fphere, we have M3 4+ Nd? = ’.. Now if we ager the pri N 2? as infenfible, we ob- » which fabfituted for 3 in } M Sime tain a near value of a= M PROBLEMS IN SPHEROIDAL TRIANGLES. M +2, gives I= i Ki very nearly, Here a queftion MM oe + M naturally arifes; oiz. To determine the value of « fuch that 2 may be obtained in this manner with the higheft degree of accuracy, of which the method is fufceptible. This will evidenily be the cafe when M is about its maximum value. So that if we put the differential of M==o, and fubfti- tute the value of the differential of a’ refulting from the proper- ties of the f{pherical triangle in this equation, we fhall have the required value of the horizontal angle. Let us fuppofe 4 and w given, and there will refult fin o/* x thant a maxi- cof, ¢ mum; whence 2 cotang. «’ cof. > (fin ¢— find) da’ +t (1 — fin a fin$?) x d?—=o. But by fpherics, ___ cof. A tang. 9 — fin a cof. » A i a! : otang. o/ — em ’ fin a’ cof. a et ete CO! 4 Ned fiesta and aa ot 6" Gna x d$; wherefore by fubftitution, 2 fin e’ cof. ot Ol. 9% (1 — fin fin 9) fin w bi 5 cof, A Ri fil, EE 1 Aifo when » and @—A are fmall, the fin oe : { Gn (?—a) +2 fin > x cof. fin = w? i and find?—{in4 4 cof, 2% x fin = a confequently 2 cof. «'* = (1 — fin ¢ fina) fin (? —a) + 2 fin a cof. > fin 3 «2 a8 Nise A a ORL OSE Re 2 cof. a cof. (= 2 fin (>) and 2 cof. a’? = 1 if we fuppofe =a nearly, and fin 2 ,? very {mall. When the horizontal angle «’, therefore, is equal to 45° or 435°, the obfervations will be nearly in their moft favourable ftate for determining the compreffion by means of our theorem. We might illu@rate this method by examples taken from the _ trigonometrical furvey of Great Britain, but on reference to it I have found fewer complete fets of obfervations than might be expeGted, and fuch as are complete in every refpeét, are not well calculated for this purpofe, the horizontal angles be- . ing 1 158 The preceding rules applicable to an ellipfoid 5 but the mana- gers of the tri- gonom. furvey avoid this af- fumption. How to apply the rules. PROBLEMS IN $PHEROIDAL TRIANGLES. ing nearly right ones. The obfervations at Beachy Head and Dunnofe give y5,¢ for the compreffion; but it muft be re- marked, that the ftate of the data is very unfavourable: in this example. The rules which our falttion gives for computing the hori- zontal angles from the latitudes and difference of longitude, — will be found, I apprehend, much fhorter than Mr. Dalby’s, | befides the advantage they poffets of affording us the means of | afcertaining the figure of the earth by a very fimple procefs, from obfervations made with the fame inftruments and by the fame obfervers. The theorems we have been peta with fome others which may perhaps form the fubjeét of another letter, would give us the relative pofition of one place to another on the fur- face of the earth, were its figure an ellipfoid of known dimen- ~ fions; but as this is ftill confidered as problematical, the me- | thod adopted by the gentlemen who have fo ably condu@ted the furvey of our ifland, is certainly preferable. They firft obtain the length of a degree upon the meridian, and its per- pendicular in a given latitude, and employ thefe data for com- puting the geographical fituations of all the places near that parallel, and not far diftant from a known meridian. In the {malier triangles the truth may be thus obtained to the fraétion of a fecond, and in the larger ones théy have very fuccelsfully employed the beautiful property of fpheroidal triangles, which ff we have fo often mentioned, } But though we give the preference to their method of com~ putation, I conceive the preceding rules will be found equally accurate, if we make ufe of the values of c, a, and 3 deduced from their obfervations ; or if we affume near values of them, and note the agreement or difagreement of the computations with obfervations made at a place confiderably diftant from the firft fiation. We may thus afcertain nearly the error of our fuppofitions, and then correét the intermediate ftations. This cautious method of proceeding is rendered neceffary by the anomalies which have been difcovered in the meafures of de- grees in different latitudes, as well as by the general rule, which ought to be our guide in all philofophical inquiries, to | frame as few hypothefes as poflible, but to make accurate ex- periments, and infer the trath from them by: fair and genuine induétion, | I mean PROBLEMS IN SPHEROIDAL TRIANGLES, 159 . I mean not, however, to fupport the opinion, that the earth The earth pro is not an ellipfoid; but, on the contrary, fhould be very loth ary aes to be obliged to give up an hypothefis, which is fo beautiful in theory, and has ftood its ground fo long. | Many of our objec- tions to it may very probably arife from errors in obfervations, or from other caufes which have not yet been fully examined. ‘The remarks of Mr, Playfair on this fubjeé are very ingenious, and I hope will be confirmed by the phenomena: but if not, Tam convinced we have not the plea of inaccuracy to fet up in this inftance, One of the ftrongeft obje@ions, however, has been lately done away. The degree of the earth meafured Abad in Lapland in the year 1736, has been found, by fome Swedith - a Lanhitl gentlemen fent there for thdt purpofe, to err in excefs by no degree removes lefs than 20S toifes. Now if we advert to the number and pre rane eharacter of the aftronomers who originally meafured this de- tained on this gree, it will be difficult for us to fet limits to the errors of @cé- other obfervers. Perhaps the anomaly in the degree at the ; Cape of Good Hope arifes from the fame caufe. Fortunately, however, the great improvements, which have Late improve- fince been made in the inftruments for aflronomical obferva- alt afgcteh ig tions and geodztical menfuration, afford us the means of bring- ing the probable errors of obfervation within very narrow limits, We may thus obtain a number of meafures in different latitudes of equal accuracy, and by comparing them tegether, the ' queftion about the earth’s figure may he puat-beyond a doubt. If this comparifen fhall be ae to give different ellipfes, we . - fhall then be fully warranted in reje@ing the hypcothefis en- - tirely and for ever. Bot till this is done, we may be allowed to adopt an hypothefis, which is fo fimple, fo good in theory, if and fupported by fo many ftrong arguments and accurate ob- Aervations, € | We have already remarked, that the degree lately meafured Mean compref- in the Mysore, compared with that in France and Englandyrgsen ee gives =, for the epemmectiion at the poles: the correéted de- gree in Lapland g gives sry and that meafured in Peru, zee: There is a ata difference between the compreflions “deduced from other meafures, but the mean falls between “thefe limits. From the beft obfervations of the length of sthe and from the pendulum that {wings feconds in different latitudes, the fame Possums " €enclufion i is alfo dea the fecond pendulum near the pole Ovi compared 160 PROBLEMS IN SPHEROLDAL TRIANGLES. compared with that at the equator, gives yZ¢ for tlie com- preffion. We may therefore affume’ y3~ as being very nearly its true value. from celeftial ire It is a curious ¢ireumftance to find the figure of the earth, regularities; deduced from the meafurement of lines and angles on its far-_ face, confirmed (perhaps corrected), by obfervations of the {tars and planetary bodies in the heavens, combined with the theory of univerfal gravitation. But fuch is certainly the cafe. «g- ofthe | Among others may be mentioned two fmall inequalities in the oe moon’s motion, which the induftry of modern mathematicians have unfolded. One of them was firft taken notice of by Mayer, and fixed by Mafon at 7”,7, but was neglected by aftronomers, as it did not fufficiently appear that fuch an equa- tion fhould arife from the theory, till Laplace traced it to the oblatenefs of the earth’s figure. Its argument is the longitude of the moon’s node, and its value has been found by Burg, from the oblervations of Dr. Mafkelyne, to be equal to 6,8, which anfwers toa wll siete: of +855. There is alfo an- other inequality of the moon’s motion in latitude, which de- pends on the fine of the true longitude, and refults from a nutation in the lunar orbit, produced by the ation of the ter- reftrial fpheroid. Burg has alfo determined the coefficient of — this inequality, from a great number of obfervations, to be equal to 8,0, which refults from a compreffion of +44,z. Remarks upon The preceffion of the equinoxes, and the nutation of the sane Pi earth’s axis, were difcovered by Newton to arife from the ob- gation of this latenefs of the earth’s figure. This famous probiem is acknow= fubject. ledged to be one of the moft abftrufe in phyfical aftronomy, and its complete folution requires the utmoft refources of the modern analyfis. The compreffion thence arifing is equal to siz, agreemg exaétly with the refulls from the two lunar in- equalities, the lengths of the fecond pendulum, and the beft. meafurements on the earth’s furface. It is well known that Newton failed in attempting to folve this problem, and fome © French mathematicians have been difpofed to pride themfelves on being the firft todeteétit. It ought however to be remem- bered, for the honour of that great man, that his miftake did not arife from any error in principle, but from his taking for granted, without demonitration, a circumftance which ap- pears highly probable, but is really erroneous, He feems to have PROBLEMS IN SPHEROIDAL TRIANGLES. 161 have firtt made this affumption i in order to florten his folution, and on finding the calculations to agree with obfervation, to have never after returned to the fubje@t. The mathematicians ‘of his time were unwilling or unable to follow him, and the queftion remained as it came from his hands, till the middle of the laft century. Had doubts arifen and objeétions been ftart- » ed, the genius of Newton might have been once more roufed to _ attion, and continued to enlighten the fciences to the laft. ' ‘But unfortunately no fuch incentive was given, and Newton “flopped fhort in the career of his glory. The evening of his life was devoted to other ftudies ; but however ufefully he may have been eniployed, there are few who will not be inclined to lament that he ever laboured in the Mint or the Reve- lations. Thus much I have thouzht it not entirely fosielg fo obferve on one of the moft remarkable effects of the oblatenefs of the earth’s figure, and in juftice to its tmmortal difcoverer, the inventor of the modern analyfis, the father of phyfical aftro- nomy, and the preceptor of Europe. Iam, Sir, Your moft obedient fervant, Port/mouth, PEREGRINUS PROTEUS, May 6, t804: - > saeinscaiaeel : > i Corrections to be made in the firft Letter. In page 12, line 20, after paper infert but. In page 15, ‘Tine 23, &c. divide the coefficient of the term — “by cof. x cof. ¢; alfo in page 16, lines 3 and 12. In page 16, line 9, dele and cof. 4 éof. oj and ta in line 14. In page 17, line 6, &c. Yor cof, w read fina, Fn page 18, line 25, for Pc, Qe, Re, read P,Q, RS, : Vou, VIII.--Jury, 1804, M Dejeription 162 NEW STRIKING PART FOR A CLOCK. IV. Defeription of a firiking Part for a Clock, in which the Intervals between Stroke and Stroke are not regulated by a Fly, but by a Pendulum. By Mr. Evwarp Massey.* SIR, , sg ig Havin G for a number of years confidered that a method of ftriking a clock, at certain regular intervals, might be of great fervice in making obfervations on the heavens, and afcer- taining the velocity of found, Sc. I beg leave to lay before the Society for the Encouragement of Arts, &c. a ftriking part of an eight-day clock, which I have no doubt will anfwer the pur- pofe intended ; and if, upon examination, the Society fhould be of opinion that it may be ufeful, I truft they will reward it according to its merit. They will find that the work of this model is lefs than that of the common ftriking movements, and » may be made by a common workman, -with lefs expence and trouble; the weight required is alfo confiderably lefs. The principle I aét upon is the pendulum, by which I regulate the ftroke, inflead of the fly; the advantage of which muft be obvious to every one. The machine confifts of a toothed wheel Ay one pinion B, a pin wheel C, pallets DD, pendulum E, and locking detent G. The hammer-work F is as ufual, and ftrikes on the bell at H. The weight hangs to thecordI. See Plate XII, Fig. 1 and 2, where a front and fide view of the machinery are given, and where fimilar letters denote the fame parts in each view. Defeription of the Machinery. I confider it is only neceflary for me to give the defcription of the wheels, fo as to be a direGtion to a mechanic, who wifhes to manufacture clocks on this principle. ‘The main-wheel A, with feventy-eight teeth, is toact ina pinion of eight leaves, B. ‘The pin wheel C fhould be large, fo that the pins on which the pallets D and the locking G aét, may be flung as far from the center as poflible, which pins may be eight or fixteen in * From the Tranfaétions of the Society of Arts, 1803. This invention was honoured with a reward of 20 guineas, ‘number. NEW. STRIKING PART FOR A CLOCK. 163 number, If eight, the pendulum E fhould be about nine inches New friking — long, and it will vibrate twice betwixt each blow of the ham- uty ees mer ; but if fixteen pins are put in the wheel, the pendulum muft be about three inches long, and will make four vibrations betwixt each blow. The pins for drawing the hammer muft _ be eight in number, and be fixed in a circle of about half the diameter of the aforefaid pins. The locking-plate is on the main wheel. The ftop is againft the pins on which the pallets aét, and may be difcharged by a flirt piece. : As I have defcribed the model, I beg leave to point out the method of ftriking a clock by the common pendulum; true fe- conds, without any additional pendulum or pallets for the ftriking part. Bik s Defeription. Fix a cantrite wheel with fixty teeth on the fame arbor with a fwing wheel of thirty teeth. Now fuppolea ftriking part to be made in the common way of making an eight-day clock, {fo far as the pallet pinion, leaving out the warning and fly pinions. A crank piece muft be fixed on the pallet pinion, which muft come into contaét with the cantrite wheel, which is fixed on the {wing wheel arbor. Then fuppofe the clock to be fet a going, and the rack difcharged, the pallet pinion will make --a@ revolution on every vibration of the pendulum, by whicli means a clock will ftrike feconds as true as a pendulum vi- brates, which I-hope will be confidered as ufeful for the pur- pofes I have defcribed, I aifo beg leave to obferve; that a great advantage arifes in both the above machines, from their not being liable to foul, as the ftroke is given by the certain and regular vibration, inftead of the uncertain motion of the fly. Its advantage likewife depends on the cleannefs of the work; and church clocks will be much benefited from the de< creafe of weight. Iam; Sir, Your moft obedient férvant, aE , EDWARD MASSEY: ~ Charles Taylor, El. ois PA ‘Hanley, in Staffordfhire; ~~ Jan. 12, 1803, leet Me. = Dygeription VERY SIMPLE TELEGRAPH. Vv. Defcription of a verry fimple Telegraph, conjifting of the Human Figure adapted to converse at a Diftance by means of Signs*, Preliminary ob- Amonc the great advantages of which thofe who do not feryations. enjoy fight are deprived, we may reckon telegraphy, which it would be difficult to fupply by another fenfe. Such an art for the ufe of the blind would doubtlefs be very imperfeét. On ihe contrary, the advantages which it affords to thofe who en- joy light, appear to me to be fo important, that it ought to be ren- dered more general, and brought within the reach of all men. For this purpofe I have offered fome notions on the fubjeét. I do not pretend. either to be the firft, or the only one who has entertained them: I even believe the contrary; and, 1 in this inftance, they will have that in common with telegraphy in general, which, though new in its execution, was not fo in its invention +. * From a {mall pamphlet in French, extracted from Mémoires fur les Aveugles, &c. t+ It is not extraordinary that the fame invention fhould have been thought of by feveral perfons. Thus the notion of telegraphy may be found in the preface to one of the German works of the ce- Jebrated Chr. Louis Hoffman, a native of Rheda, and phyfician to the Ele&tor of Mentz, which, however, does not leffen the merit of the French inventor. A defcription of the telegraph invented and executed by Citizen Chappe, is found in the interefting work of Mr. Meyer, intituled, Fragmente aus Paris, im. IV ten Fabr der Franze/fichen Republik, Hamburg, 1797. ‘The author, who was in the telegraph office at the Louvre with Cit. Chappe, affirms, that the latter had made his difcovery before the revolution, that he commu- nicated it to the National Affembly in 1792, and that the Conven- tion, on the report of Lakanal, decreed, July 25, 1793, the efta- blifhment of a telegraphic correfpondence, under the direétion of Citizen Chappe, as telegraphic engineer. A notion may be formed of the rapidity of the telegraphic correfpondence, by the following - example, of which Mr. Meyer was a witnefs. He fays, that © during his prefence in the office at the Louvre, and at the appointed hour in the evening, enquiry was made of the office at Lifle, by a Jfingle fignal, if any thing new had happened in the army of the north, and the anfwer, no, was received in 88 feconds. 4, Perfuaded VERY SIMPLE TELEGRAPH. 165 . Perfuaded of the importance of communicating our ideas at sliftances too great for the voice or hearing, I have employed myfelf in enquiries for a telegraph which fhould be at once cheap and fufficiently perfeét to be eafily ufed. 1 believe I have difcovered it ; nature herfelf has given it to all the world. This telegraph is the human body, its branches are the arms, Natural tele- which, with each other and with the perpendicular line of the 8?) trunk, may form a great number of figures, fufficiently diftinét to be readily feen, at confiderable diftances, by fimple vifion or by the affiftance of atelefcope. It would certainly be very agreeable for two friends, living oppofite to each other in an extenfive place or on the banks of a large river, to be able to converfe together. Of what utility might it be to the inhabi- ‘tants of open countries to have a method of communication which is at once fpeedy and requires no expence ! _ Thope, therefore, that the generality of readers will fee with pleafure that a method of communication is opened to them, fufceptible of being varied and brought to perfeétion by them- felves. In the annexed Plate X. are found the figns for all the Method of write charaéters in the alphabet, for the figures, and for the pun@tu- is the fignals. ation. To fimplify the writing of thefe figns, the perpendicu- lar and immoveable line, which reprefents the trunk of the body, may be omitted, as I have done, only indicating it in fome figns or charaGters by a point, as in the e and ~; and to write them with more rapidity, they may perhaps be joined in the manner of fhort-hand writers, ' Three different pofitions of the right arm, ae as many of Telegraphic ‘he other, form the figns for the vowels. The right arm rin the hu- ; ; : gure. firetched out, and a little raifed, forming an angle of about 45° with the line of the trunk, gives the fign which expreffes a; the fame arm extended and more elevated, or horizontal, forming a right angle with the trunk, gives e; more elevated, and forming an obtufe angle of about 135°, it furnifhes 7. The deft arm extended, and forming an angle of about 45° with the trunk, gives us the fign for 0; more elevated, or hori- zontal, it fignifies x; {till more elevated, and forming an angle of about 135°, it gives y. | It may be obferved, were it only to affift the memory, that _ aand o, whofe founds have fome refemblance in feveral words, are indicated by the fame fign, and likewife z and ys which in the French language often exprefs but a fingle found; with ; this 160 Ci VERY SIMPLE TELEGRAPH. Telegraphic this difference, however, that the figns for a and 7 are fornied come es ae by the right arm, and thofe for o and y by the leftarm. The a ‘two other vowels, e and uw, are likewife indicated by the fame fign, but with the fame difference. . “To form 6, both arms defcribe an angle of 45°. To form cand d, the fight arm is kept in the fame psiician’ and the left arm is raifed to the height of 90° for the firft, and of 135 for the latter. To form the letters f, g, and %, the fights arm is tenia horizontally, and the three different angles of 45°, 90°, and 135°, are formed with the left arm. To exprefs j, k or q, and J, the right arm is srk to the height of 135°, and the fame pofitions are. repeated with the left arm as were employed for the fix preceding confonants. To form m, the upper part of the right arm is placed’in a horizontal line, and the form-arm is raifed at the fame time, fo as to form a right angle with this part. To defignate n, the left arm is placed in the fame pofition. To form p, both arms defcribe the preceding figure at the fame time. Toexprefs the letters r, s, ¢, the upper part of the right arm is placed in an horizontal line, and aright angle is formed with the foresarm, while the extended Jeft arm fucceffively de- feribes the three different angles of 45°, 90°, and 135°. For v, x, and z, the Gistiei’ is done with the left arm as was done, for the three former letters, by the right, which then: forms the three angles of 45°, 90°, and 135°, If it is ihterided to thew that a telegraphic fignal is termi- nated, the two arms are withdrawn, fo as to form oe one line with the reft of the body. The right arm put at reft, fo. that the hand is fupported by the hip,” indicates the termination of a word. The left hand placed i in the fame pofition, is the fign of a comma, (,). The two arms put in this pofition, fi fignify a point and a ‘comma, (;).: By putting the right arm into this pofition, and at the fame time muking the fign of m with the left hand, two points are indicated, (:). _ By refting the left arm on the hip, and making the fign shin with the right arm, a point is indicated, (. ). i VERY SIMPLE TELEGRAPH. - 167 By holding the right arm in fuch a pofition that the hand Telegraphic fhall be above the head, or touch it, the point of interrogation bs ett i is made, (2). | pa The fame motion performed with the left arm, furnifhes a fign for the point of admiration, (!). _ The three figns of the termination of a word, of acomma and of the point of interrogation, each combined with the three different angles made with the other arm, form the nine figures. By putting the right arm at reft on the hip, and forming th three angles of 45°, 90°, and 135°, with the extended left arm, the figns are given for the figures 1, 2, and 3. By refting the left arm on the hip, and making the fame three angles with the right arm, the figures 4, 5, and 6, are formed. By bringing the right arm to the fign of the point of inter- rogation, and repeating the three angles with the left arm, the _ figures 7, 8, and 9, are formed. To indicate zero, (0), the two arms are raifed fo that the hands fhall be above the head, or touch it, . Toexprefs 10, the figns of 1 and 0 are made without making either the fign of the termination of a word, or of a number, or that of acomma, between thefe two figns, To exprefs 11, the fign of 1 is twice made, with the afliftance of the fign for the termination of a character, or of a figure. ‘To indicate 12, the figns of 1 and 2 are made, and foon: 10, 11, and 12 may be expreffed at pleafure, each by a fingle fign, by placing the left arm in the pofition of the point of admiration, and by fuc- ceflively forming with the right arm the three angles of 45°, 90°, and 135%. It would not be difficult to devife a great _ number of figns to exprefs 13, 14, 15, and many other numbers, each by a fingle fign. If it be intended to make ufe of this natural telegraph at the Mechanical ad- diftance of one, or even of feveral leagues, or tq do without i great - telefcope at lefs confiderable diftances, it is only neceflary to : add to each natural arm an artificial one, that is to fay, an oblong frame, of the breadth of a foot-or thereabout, and of - the length of one or more yards. This frame muft be covered with oiled filk, or any other fluff of a dark colour, and muft be provided with a handle to hold and direét it. Our telegraph | _ would here no longer be called natural, but it is till among : the inf ! a/ 168 May be ufed by night as well as by day. Si VERY SIMPLE TELEGRABH;’ the moft fimple of the artificial, Jam of opinion that thiskind — of telegraph may be employed with very great advantage: it is fimple and cheap; it may be ufed in all direGtions, and is removed with eafe. In this latter point of view, it would doubtlefs he well calculated for the formation of moveable te- Jegraphic lines, or what might be called a flying telegraphy, which in my opinion would. be very ufeful in war, to keep up a quick and conftant communication between the different bodies, and with the fixed and common telegraphic lines. A machine of eafy carriage, and calculated to raife aman to a confiderable height, would, no doubt, contribute to render the flying telegraphy more perfeé. The telegraphs with. the frames may be ufed by night as well as by day, by adding lan- terns to them, as in the common telegraphs, One enh be placed i in the middle, that is to fay, on the breaft of the perfon who forms the telegraphic fignals with his arms and the frames, one at the handle, and one at the extremity of each frame. To prevent the perfon from being affe€ted by the vapours of the lentern in the middle, it fhould be placed at.a fimall diftance before him; and when the movements are intended to be vifible on both fides, it would be ftill better to place this lantern on the head, or to put one on each fhoulder. ¢ Perhaps this kind of telegraph might be advantageoufly em- ployed to eftablifi immoveable telegraphic lines, inevery cafe in which the telegraphs employed at prefent would be too ex- | penfive. The fame telegraph might frequently ferve for feve« ral lines in: different: direétions, By. means. of this telegraph a communication might be maintained, with little coft, even in final diftriats, or in the provincus and departments, with the — capital or the chief place, and the other confiderable points, — Of what importance may it be to be able to indicate inflantas — neoufly conflagrations, inundations, or other: events which res quire {peedy fuecour, It would be well to place the telegraph, or the perfon who makes the telegraphic fignals, on akind of ftool, to facilitate his by movements. Placed in this manner, with his arms and the y frames he could make a prodigious. number of figures, fufhi- ciently difting not to be confounded with eacly other. Account WATER HEATED [N'A BOILER OF STONE. 169 VI. Account of «a Fat refpedting Water heated in a Boiler of Stone ; with Obfercations. By Mr. J.C. HoRNBLOWER. To. Mr. NICHOLSON. Dear Sir, ‘Lyoucu it muft be admitted by every one who has at- Fluids not tended to the critique contained in your note on the experi- naa ments of Count Rumford, -in your firft volume * of the Philo- 3 fophical Journal, concerning the non-conduéting power of fluids with regard to heat, that it is an erroneous conclufion, and which feveral experiments, particularly that of Mr. Murray, have fince confirmed ; yet I cannot be quiet without informing the gentlemen who have fo conftantly oppofed the Count’s doétrine, of a circumftance which accident brought Incident. forth on a very largefcale, about forty years ago, in the county of Cornwall, : It had long beena defideratum in the mining intereft in Attempt to re- that county, to reduce the confumption of fuel in draining the pease mines by the means of fteam engines, and every expedient in working ihat carried any tolerable face of probability was brought to a *¢#™ engines. trial. ' Among the reft it was fuggefted, that as, in the feveral Trial to work operations of {melting the produce of the mines, much heat py the sie muft be carried off, from the intenfe fires of their furnaces, which might be employed to fome purpofes requiring but a ‘fubordinate temperature ; a refolution was formed by a com- pany of gentlemen, with Mr. John Wefton at the head of it _* {to whom mining was an ungovernable hobby-horfe), to ereé an engine on a copper mine in the parifh of Camborne, and to put up a fet of furnaces fo attached to the engine that they might avail themfelves of this fuperabundant heat to raife the fteam. i To effeét this they had their engine-boiler made of mafonry, A ftone boiler _ of what is called in Cornwall moor-ftone, well wrought and put conneéted with water-lime, &c. together with Aberthaw lime, which has the property of fetting heated by cop- j per tubes. * J. Page 291, Quarto Series, ¢ like 170 WATER HEATED IN A BOILER OF STONE. like the Dutch trafs*; and to convey the heat, two or three copper tubes were placed in it ‘from end ‘to end, and the fur- naces connected to one end of the boiler, and the engine at the other; which, though it was a prodigal way of faving heat, yet it was competent enough te raife fteam for the ufe of the engine in certain cafes, When the water At the bottom of the boiler was placed a cock, as ufual, to Segre a pee tap it as occafion required, either when it was neceflary to near the bottom q y gave water, but clean it, or in cafe it fhould be over-charged with water, Brtle heated, = Which I think was the cafe which brought the following faét to light; namely, that when the fire had been lighted, and the heat sia to circulate through all this mafs of ftone-work, and the water brought to boil, and the engine had been at work tor the firft time, which is ufually attended with many unfore- feen delays and hindrances, the cock being turned, the water was not hotter than to admit the hand without any painful fenfation of heat. Many deep and grave hypothefes were formed on this extraordinary difcovery, which, for the fake of the profeffion at this advanced ftate of f{cience, I muft forbear to mention. But at that period many a valuable truth had come and gone like a worthlefs mendicant, whom few re- garded, and whom none would receive. The tubes were The moft ftriking circumftances in the detail of this difco-. near the furface, and the vefela. Very are, that the temperature downward (for the tubes were pad conduétor, near the furface of the water) muft be greatly accelerated by _ the conduéting power of the fides of the boiler, and the agitae tion of the water ina ftate of ebullition: notwithftanding all, it muft have occupied four or five hours to bring the lower part of the water to the temperature of 90°, or perhaps 100°; and no doubt can be entertained but that they deemed it a matter of no confequence as to the place of the tubes, fo long as they were covered with water; believing with every Gada elfe, that the whole mafs would attain the boiling point at the fame lime. Hail the man who throws if but one grain of truth into the icale againft popular prejudice or vulgar error; and notwith- ftanding the Coynt did not obtain the extreme of precifion in this particular inftance, he has laid the foundation for all the fubiequent experiments which have gone to confirm or reject * This lime is found on the beach on fome part of South Wales. the ON GALVANISMe 17} the pofition he advanced. This I may be permitted to obferve, without the imputation of detra@tion from thofe whofe labours and talents demand my refpect. lam, Sir, Your very obedient fervant, City Road, J. C. HORNBLOWER. June 11, 1804. ) Vil. _ Facts and Obfervations tending to elucidate the Theory of Gul- vanifm. By A CoRRESPONDENT. Tue pile of Volta has difclofed many new properties which General effeéts _ were not known to belong to the two powers of the eleétric mh a ee fluid, for by its operation, two fets of chemical phenomena are produced, differing effentially from each other, thereby de- _ termining the real or pofitive nature of each power. It has introduced eleétricity as a chemical agent, and has fhewn us that it aéts as fuch in its two-fold charaéter very generally throughout nature. Eleétricity has hitherto been confidered moftly as an adventitious power excited upon the furfaces of bodies, it is now known to attach itfelf to, and to enter into combination with various fubftances. If the fpinal marrow of a frog be coated with tin foil, and _ the mufcles of the lower extremities be laid bare, if the frog, thus prepared be drawn through water, at the bottom of which there is a piece of filver, when the tin foil touches the filver, _ the limbs of the frog are thrown into ftrong convulfions, If the tin foil be kept fteadily at the firft place of contaét, the convulfions foon ceafe; but if it be removed to the fmalleft diftance from where it firft touched the filver, and is again in - contaét with it, the convulfions are renewed with their origi- nal violence. The fame thing happens when the filver iscon- -neéted with the’ mufcles by means of a metal, though that metal touch the mufcle in a point, as when the water aéts as | the conduéting arch. Thefe experiments fhew that there is a a pow er in each ese able particle of the metal which excites the aétion of the at cles, and that nothing but the contaét of the metals feems ne- ceflary for the produétion of the effect, It 172 General effeéts and theory of galvanifm. ON GALYANISM, If the power which excites the motion of the mufcles be eleGtricity, it is in a ftate not to be conducted from one parti- cle to another, for the fame effe& is renewed whenever the tin-foil comes in contaét with another part of the filver, how- ever contiguous it be to the one at firft touched. We find farther that the fuperficial particle does not take off the power of the one immediately beneath. It is thus, I apprehend, that the renewal ak furfaces gives a permanency to the powers of the pile, and in proportion to the quicknefs of fucceffion in the prefenting new furfaces, the power of the pile is found to increafe. It is needlefs to explain thefe appearances by the hypotheti- cal principle of Mr. Lavoifier’s oxygen, fince Mr. Volta has fhewn that the metals themfelves are ele€tro-motors, even with- out the intervention of water, or the a€tion of acids or alkalis, Taking it for granted then that the animal mufcles are a {pe- cies of ele€trometer, we may conclude that fome difturbance of electricity takes place when two metals are brought in con- — tact, and a circuitis made, This difturbance varies according to the fubftances employed. Mr, Volta has found this to be the cafe, for he has rendered this {mall portion of eleétricity perceptible by accumulating it on his condenfer. The pile of Volta accumulates the power which is called forth by the con- taét of two metals, and enables us to apply it in fuch accu- mulated ftate in various chemical experiments. One of the moft ftriking effeéts is the difengagement of two elaftic aeriform fluids from water, by introducing wires, from which are produced the two ftates of the eleétric fluid. Thus it happens that the wire conne¢ted with the zinc produces, — when immerfed in water, one gas, and the wire connected with the filver or copper plate another gas, The properties of thefe gafes are perfe@tly diflin@, and evince that the pro- ducing powers have peculiar effe@s, for the water is common to both, What takes place from the wires in water at the exe tremities of the pile is more or lefs apparent between the plates themfelves, where wetted paper is interpofed, for there the action of the gafes-is to be feen in their effects on the metallic plates. The effet produced by the pile may be greatlyin- creafed by arranging it in the following order; filver, wet paper, zinc, a plate of glafs, &c, and by placing wires on each fide of the glafs, and putting thofe inte water; fromeach — Paty ON GALVANISM ; 173 pair of wires the two aits will be produced. Might not Mr. General effects Wilkinfon’s experiment of burning charcoal be in this manner PI a ot greatly increafed in fplendour? In the profecution. of the prefent inquiry, I thall efpecially notice the two different effe€ts produced in water by the wires of Volta’s pile. It is known that thefe two wires throw out two powers fimilar to what are called pofitive and negative ele@tricity; and as water is common to both, I am led te con-- clude that the two gafes are produced in one inftance by the union of one of thefe powers with water, and in the other by the other power and water, and to confider each gas as thus compounded, becaufe we have no evidence of any other power, principle or fubftance being acceffory to the produce tion of either of the gafes. Volta’s pile caufes combuftion in atmofpheric air, and therefore vital air is abforbed; it caufes another f{pecies of combuftion in vacuo, becaufe the two prin= ciples of fire are fupplied by it. Volta’s pile does not aét in wacud, becaufe the refiftance neceffary to accumulate the powers is withdrawn in the fame manner as the Leyden jar ~ does not charge in vacuo. If the gas which is produced from one of the wires com- municating with the pile in water be united and inflamed with the other in a juft proportion, the water which is common to both is re-produced, and common fire is generated in great abundance; now as we have had no evidence of the prefence of fire till this point of time, does it not appear that thefe two principles which are thrown out from the wires of the pile, are by their union transformed into ordinary fire, and does it not _ appear in this experiment that ordinary fire is generated by and _ compounded of thefe two powers? Lavoifier has triumphed over the friends of Phlogifton. He overturned a fyftem which was built upon the affumption of a principle, upon a mere name of hypothetical entity, endued with attributed or imaginary properties. But in the place of the fyftem he deftroyed, he has erected one of his own. Has he not built upon the fame weak foundation with his late ad- -verfaries? Does not his fyftem reft altogether upon the aflumed diftinét exiftence of things, the diftin@ exiftence of which can- mot in any way be evinced? Do not all his folutions of chemi- _ ¢al phenomena depend on fuch affumption? May not all thefe phenomena be explained with equal eafe, nay more fimply, iby referring them to the aétion of known agents ? if 174 General effects and theory of galvanifm. ON GALVANISM. If we examine Mr. Lavoifier’s theory of combuftion, we fhall find that it depends upon the affumption of a principle whofe exiftence has never been proved by dire&t experiment. It is the union of the bafis of oxygen gas with the combuftible body which in every inftance is the caufe of the combutftion, We have feen that this gas is produced by pofitive eleétricity and water, and we conclude that the ponderable part of this gas is water, becaufe we can perceive the agency of no other principle or fubftance. The fimple condenfation of oxygen gas, according to Mr. Lavoifier, occafions the evolution of heat and light. But little heat is excited by the mechanical conden- fation of this gas; but we find that when a chemical union takes place between a combuftible and the gas, a eregt penton of heat and light is difengaged. The accenfion of charcoal and metallic bodies by the gal- vanic battery, even in vacuo, feems to fhew that the eleétri- cities thus produced are the peculiar agents in the phenomena of combuftion. They feem not only to be the exciters of com- buftion, but they furnith with water thofe gafes by which com-= buftion has been conceived to be upheld. The theory of the Lavoifierian fchool, of the combuftion of hydrogen gas, in conjunGion with oxygen gas, is as follows: ‘© When both gafes are mixed at a lower temperature than that of ignition or red heat, the attraétion of their refpeétive bafes to the caloric is, in that cafe, ftronger than their attra€tion to each other, and therefore they are not decompofed. But in the heat of ignition, their bafes, namely concrete oxygen and hydrogen, again attraét each other more ftrongly,’ and hence they unite to produce water; and both the calorie and light by which they are retained in their aerial weigh: are ni dif- e ngaged from them, and conftitute the fire.” Now where is the evidence of the heat and light being ne- ceflary to the formation of thefe gafes, when they are produced from the wires conneéted with the extremities of the pile, and placed in water? Alfo during the oxidation of a metal in the moift way, the hydrogen difcharged is at firft very hot, fo as. to heat immoderately the tubes ufed in colle@ting it. If the condenfation of oxygen gas be the caufe of the produétion of heat and light, how comes it that charcoal and nitre deflagrate together with the produdtion of fo much light and heat, although, the compound formed, namely, carbonic acid gas, oceupies fo — . much ON GALVANISM. 175 tiuch more fpace than the fubftances from which it is formed? General effeéts _ Does it not feem an affumption to fay that the two conditions 24 theory of ‘ E E galvanifm. _ of oxygen in the aeriform itate, and oxygen in the folid ftate, 4s in nitre, fliould hold the fame quantity precifely of heat and light? This faét difproves the opinion that the produétion of heat and light is commenfurate with the condenfation that takes place in combuttion. \ An eftablifhed law of chemical affinity would be reverled, if oxygen, when in combination with another fubflance, were to have a greater, or even the fame attraction for the matter of heat as it has when oxygen is fimply combined with the matter _ of heat. There are many inftances of combuftion, deflagration, &e. wherein the compounds formed feem to hold moreheat in their compofition after than before combuftion. . When gun-powder is inflamed, does not the produétion of fteam feem to fhew that a great quantity of heat is generated during the explofion. If the matter of heat was held to the particles of the component parts of gun-power, in confequence of their great capacity for containing it, fhould we have any reafon by analogy to ful- pect that the ele&tric {park would entirely reverfe the order of the exifting attraGions? Have we not evidence of the accu- mulation of one power of the pile in nitrous and muriatic falts, for in the formation of their acids we do not find combuftion _ to be neceflary, and there is no known expenditure of this their i igneous principle. Thefe are the falts which caufe the combutftion of inflammable bodies, and burn them, in confe- " quence of their both containing igneous and inflammable prin- ciples. Thus does it appear et fire is generated during com- _buftion, _ From all the obfervations and experiments I have Fads on this fubje&, I conclude that water is ftill to be confidered asa fimple fubftance, that its two affumed component parts are non-entities, that fire is generated in every fpecies of com- buttion, whether by acids or otherwife, and that heat is gene- tated in the lungs during refpiration. I take the liberty alfo to fuggeft, that the admiflion of the hypothetical fubftances of the Beate crian fyftem may have retarded the progrefs of {ci- ence, by diverting the mind from real objects. Analogies _ drawn from imaginary data muft tend to perplex and confound, and thus-do names arife without exifting realities. Perhaps it + would 176 EXPERIMENTS WITH THE ELECTRIC PILE. would be as proper to queftion the exiftence of azote, if oxy- gen and hydrogen were to fail, as it was to admit it, from the fuppofition of the exiftence of thofe two fubftances. A CORRESPONDENT. VII. Experiments with the Ele@tric Pile, by Mr. Ritter, of Jena. Communicated by Mr. OxstTED.* V V HILE the great inventor of the ele@tric pile was proving | the identity of galvanifm and electricity, many of the philofo- y 4 phers of Germany were butied in the fame purfuit. On this | fubje@ the celebrated Ritter undertook a very extenfive feries | ‘of experiments, the refults of which are fo remarkable as to’ 4 merit attention, even after the publication of the labours of f the philofopher of Pavia. | To compare gal- 1m order to compare galvanifm properly with eleétricity, jf vanifm with four different phenomena are to be diftinguifhed; the kind of jf pene Fe ele€tricity, chemical action, fpark, and fhock. the kind, chee © Asto the kind of eleétricity, it is known to every perfon, | ce eeeaed that the pile has two eleétrical poles, one pofitive, the other t. Kind: negative. Ona more attentive examination wedifcover, what — The pile has a was not difficult to forefee, that the refpeétive intenfities are — pofitive and a F h h sat Ph oth d larly d Tes negative pole : rongelt at the extremities of the pile, and regularly decreale and bs aie from the extremity to the centre, where the intenfity is at its | anally from the minimum. But it was never yet fufpe@ed, that the whole pile’ > exremities to the becomes negatively ele@trified, when a communication is made A centre. | But the whole Detween the pofitive pole and the earth, by means of fome con-_ pile becomes ne- duéting fubftance; and on the contrary, the whole pile be- © or toate i comes pofitive; when the ele@tricity is abftrated from the ne- made tocom- ative pole. We have here a phenomenon, that fhews the’ oe e theory of eleétricity to be ftill in its infancy: When the ftate of 1 means of acon- the pile is thus changed, its chemical aétion is not deftroyed,. : co and vice but continues as before. This faét is perfeéily confiftent with Werjae Yet this change the augmentation of the chemical aétion of the pile, on the in the kind of addition of falts, acids, or alkalis, to their wet ftrata, in which: letrici e eae * cafe the kind of ele@ricity remains conftantly the fame as whent chemical aétion. fimple water was employed, A collateral fac | } feok. , 4 a 2 eh wi °" * Journal de Phyfique, December, 1803, Vol: LVU, p. 401s. * adding a falt to The the water without changing the kind of cleétricity. 2G EXPERIMENTS WITH THE ELECTRIC PILE. 177 The affertion of Volta, fince repeated by Van Marum and Volta, Van arum, and Pfaff, that the eleétrical pile charges a jar or a battery inftan- prs, fay; that taneoufly, requires fome limitation. the pile changes Wi ; bei », a Jar inftantane= ith regard to common piles, the affertion is true: but if oyqy, the pieces of pafteboard, inftead of being thoroughly wetted, This is true with contain but very little moifture, that of the damp air for ex- ewe . hdd ? i ample, the a@tion takes place much more flowly. At firft, in- pafteboards be deed, the aétion is ftill tolerably prompt, but in proportion as little moiftenedy f . ; the jar will be the pafteboards lofe their moifture, the action becomes gradu- charged more ally flower; fo that a pile of fix hundred pairs of zinc and cop- 1°w!y- 5 : A i Such a pile of per, ufed immediately,after it was made, was ten or fifteen 600 tae va minutes charging a battery of thirty-fix {quare feet to the fame ° 15 minutes : F Hc g a bat- degree, to which it would have charged it inftantaneoutfly, tery of 36 fee had it been conftru@ed with pieces of pafteboard thoroughly as eg as it wetted. Each of the wet ftrata too may be compofed of a Nay alc ha. 6, ° piece of glafs, armed on each fide with wet pafteboard;‘and with thoroughly fuch a pile of fix hundred pairs would require twelve hours to pot Pateboards y interpofing charge the battery to the fame degree, as would be done by a glafs armed with common pile, with a folution of a falt, in an imperceptible W*tPa%cboard ; ee a : betweén each pair {pace of time. The law of this retardation therefore is, that of metals, che the aétion of a pile is more flow, in proportion as it is aworfe re eee , protracte ie} conduétor. twelve hours. Ritter has made a great number of experiments in particu- The action ofthe : 4 ile therefore is lar, which prove, that the ftate of the pile, on all occafions, aac ae ‘obeys the fame laws, as that produced by the eleétrical ma- ticn to its con- chine: but we cannot here enter into particulars, without ex- I de ceeding the bounds allowable to an abftraét. proved by many It is a well known fa@, that eleétricity produces the fame °xPetiments that : f : _ _ the ele€tricity of change in wateras galvanifm. Ritter has fhown, that pofitive the pile obeys the fo 3 ‘ } 3 ‘ . : fame laws with electricity, like pofitive galvanifm, difengages from it oxigen eee tokind gas; and that negative eleétricity, like negative galvanifim, dif- as that produced engages from it hidrogen. — by the machines eee a = y ; 2. Chemical Inquiries into the aétion of the pile on metals have taught ajon. him, that its negative pole difpofes them to combine with the Ga'vanifm and _hidrogen of water, as the pofitive pole difpofes them to com- gai Ge Ae bine with oxigen. The hidrogenation has different degrees change in water 3 with refpeét to the fame metal, as well as the oxidation, Sil- yaaa a ag ver with a large quantity of hidrogen affumes the ftate of gas: tricates from it with a fmaller quantily it remains folid. He alfo found, that ee ae the eleétricity does not produce oxigenations and hidrogenations drogen. in the humid way alone, but in the dry way alfo, The oxida- se ariarwt. Vor. VIII.—Juxry, 1804, N tion Bifpofes ifeals ie 178 EXPERIMENTS WITH THE ELECTRIC PILE, combine with the tion produced by the pofitive pole is eafily obfervable. No- hidrogenof —_ thing more is neceffary, than to arm it with a leaf of gold, and water 5 the po- a ‘ i : aes fitive with its the negative pile with a bit of charcoal; when, on bringing oxigen. them into conta&t, the gold leaf will burn with a bright flame, The hidrogena- : tion of metals and the charcoal remain untouched. If the charcoal be placed has neat in contaét with the pofitive pole, and the gold leaf in con- shai eis ** taét with the negative, the charcoal will burn, and the gold tion, _ melt. The hidrogenation produced by the negative pole is pi ae lefs diftinét, fo that it is feldom perceived: but faéts may be comesa gas: lefs adduced however, that prove its exiftence. If a little veffel Gieaewsis of iron or platina, filled with mercury, be placed in contact drogenates and With the negative pole, on touching the furface of this fluid oxigenates me- metal with the pofitive conductor, we obtain a point or circle tals in the dry : é way alfo. of a powder very different from the black oxide of mercury, If the pofitive which is produced when the mercury is placed in contaét with pole of the pile : : : be armed with the pofitive pole, and touched with the negative conduétor. — gold leaf,andthe The oxide produced in the latter cafe arranges itfelf in the reg abies figure of little flars, equal to thofe produced by pofitive elec- on making the tricity with the powder: and the circular figures on the mer-~ big a ee cury at the negative pole are likewife equal to thofe produced with a bright by the powder eleétrified with the negative condu€tor. seco Pc In a pile the poles of which are not made to communicate unaltered : by means of a conduting fubftance, the chemical aétion of the sat ees: firata compofing it is very unequal. The plates of zinc are verfed, the char- Oxided lefs in proportion to their diftance from the pofitive coal willburn, pole; fo that thofe neareft the negative pole have frequently | and the gold Piece Ni mele, no traces of oxidation, and feem rather to have been proteéted The hidrogena- from the aétion of the water by which they are wetted, than ae rats Ci attacked by the aétion of the pile. This may be rendered ftill | mercury, ina more evident by placing every fifth pair incontaét with aniron — Mean heed wire, the other end of which is plunged in water. In this — in contaé with experiment the oxidation of thefe wires will be m the inverfe — bsipiel ts ratio of their diftances from the pofitive pole; imthecentre the et ace by wire will not be more oxided than another fimply plunged in ana anaet from water for an equal length of time, and all the wires beyond — padpeges + this will be ftill lefs oxided. Henceit is evident, that another _ a powder differ- a€tion, the reverfe of oxidation, has taken place. a er a Of all the effects of the pile, its aétion on the human body iq which is produs has been leaft examined. The fhock, or rather palpitation, pean is that it excites, has been confidered as too fimple, to be fub- vl ftances, will be jected to ftrict inquiry; and the flath, as wellas its aétion on _ found on the the. a, durface. ~ a EXPERIMENTS WITH THE ELECTRIC PILE. 179 the tongue, has drawn but flight attention. It is true thefe ae oe . : . > . sac K inquiries, like all others relating to organized beings, are very airanges itfelf in difficult, particularly when they concern an action that is fre- ftars, as when eed se - : eleétrified by the quently injurious to the living fubjeét. Ritter has more than ne sith once paid for the following difcoveries, by long and even dan- tively 5. and the P ircular fig gerous fits of illnefs. peas pack It is well known, that the fkin, being a bad conductor, muft femble thofe pro- i gaa ag Sag . ., duced by elec- be wetted, to make it a good one: it is likewife found in prac evifying Cheba tice, that a furface of confiderable extent muft be wetted and der negatively. armed with metal, to have all the poffible effect of a pile, When the poles =a : 3 ; are not made to The reafon is not difficult to difcover, though it may lead to communicate by many important confequences: we have only to advert to the ™eans of a con- ‘ : dudor, the chee ‘known faét, that conduétors can only convey a quantity of gical ction of ele€ricity proportionate to their furface; whence it follows, the ae pa. that, to produce the greateft effe€t, a confiderable extent OF arte oe acted fkin muft be made a good conduétor. If one of the furfaces oxided lefs in wetted and armed with metal, which is touched by the con- tel akg VA duttors of the pile, be larger than the other, the fenfation is from the pofitive Jefs diftinét than that which takes place on the {maller, where Poles and thofe : . : ; : nearer the nega- there isa more perceptible, and often painful fenfation: fo that tive pole Rech we are mafters of the magnitude of the effeét that we would tohave been pro- : : tected fi i produce on any part of the body, a very important circum- 6.0, ae fiance in employing galvanifm medicinally. If every fifth The following is an application of what has juft been faid. ee with’ aod All the difference between the fhock obtained from the pile, wire communis and that received from a jar, arifes from the different ftates in ae. vee a which we are when we touch them: if a very large pile be dation of the touched with dry hands, we experience the fame fenfation, as a hee . . . . MVerile ratio if we had touched a charged jar: on the contrary, if with of their difance hands thoroughly wetted and armed with metal we touch a fiom the pofitive pole; the cen- jar previoufly difcharged by dry hands, we receive a thoek trai wire will not fimilar to that of the galvanic pile. be more oxidedy Ritter reduces all the effeéts of the pile on the animal body Mae to expanfions and contrations, By the pofttive condaor he water, and the has made feveral parts of the human body affume a greater “'T°s toward : the negative pole bulk ; and by the negative he has made the fame parts con- will He pweraee tract. When the tongue is brought into conta@ with the po- mie from oxi . as. . t10ONe fitive conductor, applying the negative to fome other part ek Sparke of the body, and they be all lefta few minutes in this flate, a and thock. little rifing is produced on the tongue: the negative condu@or, eee ‘al placed in contaé with it in the fame manner, produces a little human body has * been leaft exae 2 “s “ N 2 Gepreffion, ea, 180 EXPERIMENTS WITH THE ELECTRIC PILE. It isin fa&t mot depreffion. If the wet hands be kept a few minutes in con- difficult : . . a mer oN taét with the poles of the pile, the pulfe of the hand in con brought on him-ta¢t with the pofitive pole becomes fenfibly ftronger, and that felf long and of the hand which touches the negative pole weaker. Mr. dangerous fits . . - 5 ; a of illnefs by his Ritter has given us many particulars on this fubje¢t, and is em- experiments. ployed in making additions to them; but we fhall content our- The fin, © felves with obferving, that the expanfion is followed by a fen- form a good i : : conduétor, muf fation of heat, the contraétion by a fenfation of cold. Be eres The aétion of the pile on the organs of fenfe is modified by and this to acon- - bane fiderabie extent, the particular nature of each; but it is remarkable, that the oer es two poles of the pile produce in fome fort the two extremes If the as of each fpecies of fenfation. I have already obferved, in the wetted and armed abftract I gave af Mr. Ritter’s difcoveries on light fome time with metal in s : : two places, and @g0, that the pile produces in the eyes thofe red and blue co- pans ~ lours, which are nearly the extremes of thofe of the prifm ; tee ce te and if it were not fo difficult to diftinguifh the violet from the pa ag es the blue, undoubtedly we fhould have nothing to wifh in this re-- ] le 4 . se Beat {pect. In thefe experiments, the eye in the pofitive ftate, tible, and often while it fees every objeét of a red colour, fees them at the pont: fame time larger and more diftinétly : in the negative ftate, on hence we ¢an ! : command the the contrary, it fees them at once blue, fmaller, and lefs dif- magnitude of ting than they ufually appear. the effe& : oa pate Thus the expanfive power of the pofitive pole, and the con- onthe body. _—_traéting power of the negative, feem to exert their aGtion here ‘The difference Tleow:ife between the : fhock ie the The tongue is equally affeted by the pile: the acid tafte i d 7 - 4 ait hela. produced by the pofitive conduétor, and the alkaline by the — arifes from the negative are {ufficiently known. 3 pinata, x we The effeé of the negative conduétor on the nofe is an am- touch them. If moniacal {mell ; that of the pofitive is a depreffion of the fen- — we touch a large “Thaaniatl phe teinaeataats mailer. fe : - 7 pile with dry fibility of the organ, I what is produced by the oxi- — hands, were- genated muriatic acid. : pore be The ears, touched by the pofitive conduétor, hear a grave q . t . < 7 mr a wie found, and with the negative, a found more acute. ted and armed Thefe experiments require much care: to repeat them pro. nk ae perly it is neceflary to read the defcriptions at large, which the > charged previ- author has given in different traéts, where the particulars are onfly by dr . = baa Y al minutely detailed. the fame fenfa- tion as from the pile. Ritter reduces al! the effe& of the pile on the body to expanfion and contra¢tion ; the pofitive conductor expanding, the negative contracting the part. The pulfe is made ftronger by the pofitive conductor; weaker by the negative. The expanfion is fole lowed by a fenfation of heat, and wice verfa. ‘The aétion of the pile on the organs of fenfe depends on the nature of the organ; but the two poles produce the extremes of the fenfation. _ The eye in the pofitive ftate fees objects red, large, and diftin€&; in the negative, blue, {mally and move ob{cure. On the tongue the pofitive pole produces an acid tafte; the negative, am alxaline. In the nofe the negative produces an alkaline fmell; the pofitive, that of oxigenated. muriatic acid. In the ears the pofitive produces a grave found; the negative, an acute MACHINE FOR LAYING LAND. IX. Account of a Machine for laying Land level. By Mr. Davip Cuartes*, "Turs fimple machine, which is the invention of my Steward, and of which I have feen nothing fimilar, appears to me neceflary, even in the moft fertile parts of England, where the new fyftem of drill-hufbandry bas been introduced, or even where there is any attention to the wafte of time, or to the eafe of cattle in the act of ploughing ; in order to get rid of crooked or unequal ridges, without either a fummer fallow by crofs ploughing, or elfe by frequent repetitions of plough- ing in the winter and fpring, which the humidity of our climate will not allow in every kind of foil. I reduced fourteen acres of land laft fpring to a perfe& level, where the crowns of the ridges were above two feet higher than the furrows, and where they were crooked and of unequal breadths, Six acres of this is now under turnips, a crop that gives fufficient time to ameliorate the under-ftrata of foil that had perhaps never before been expofed to the in- fluence of the fun and air; and by the adoption of the North- umberland mode of fowing that root on dunged drills, it is almoft immaterial where the upper ftrata is, provided the feed vegetates, as it foon ftrikes into the manure, and rapidly flourifhes. My chief fuccefs, however, has been upon a field of eight acres, which lay in the unprofitable ftate already defcribed. This land, which is a deep clay, and which had produced a crop of wheat from an old lay fod the former year without any manure, was winter ploughed, and lay in that flate until the leveller was introduced the firft dry weather in April. It was preceded by two horfe-ploughs, taking perhaps a {quare of an acre at once: thefe loofened the foil the depth of a common furrow, and twice the breadth acrofs the ridges, The leveller followed, drawn by two oxen and two horfes, with a man at each handle, to prefs it down where the weight is to be removed, and to lift up the body by the handles * From the Tranfactions of the Society of Arts, who rewarded the Inventor with their filver medal. The communication was made by Lieut. Col. Hardy, of Weftmead, Carmarthenfhire, . where 131 Account of a machine for lays ing land level. 182 Account of a machine for lay« ing land level. MACHINE FOR LAYING LAND. where it is to be difcharged. Thus four men, one driver, and eight head of cattle, wil more effectually level from half an acre to -three roods in one day, according as the earth is light or heavy, than fixty or eighty men would accomplifh with barrows and fhovels, &c. even with the affifiance of a plough. In fandy ground where the depth of one furrow will bring all to a level, as much will of courfe be done in one day as two ploughs can cover; but my ground required to be gone over feveral times, After this field was levelled, the backs of the ridges, as they are termed, which were firipped of their vegetable mold, were ploughed up, the furrows not requiring it. They were alfo harrowed, and the field copioufly manured with lime compoft; harrowed in, and broke into nine-feet ridges, perfe@tly ftrait, in order to in- troduce Duckit’s drill, It was fown under furrow, broad- caft, the laft of it not until the 13th of May, and was cut down a reafonable crop the 4th of September. Iam now thrafhing it, and a fample fhall be fent, as well as a return of the eight acres if neceflary. The field now lies in proper form, well manured, with the advantage of a fair crop from heavy tenacious ground, with- out lofing a feafon, and in a year by no means favourable. I am well aware there are many fhallow foils, where it may be hazardous to remove the enriched furface, and truft perhaps one half of your land for a crop that had never before been expofed to the atmofphere ; but where the foil is fufficiently- deep, or you have good under-ftrata, and there is manure at hand to correét what is four from want of expofure and tillage, it is evident from this experiment that no rifk is run. To avoid the expence of a fallow, and to lay out ground in flrait and even ridges, even where drill hufbandry is not. pradifed, fhould be objeéts to every rational farmer. But where the new f; {tem is intended to be adopted, it becomes indifpenfably neceflary. In laying down lawns, parks, &c. where furrows are an eyefore, or places inacceflible to wheel carriages from their declivity, and frem which earth is to be removed, it will be found equally ufeful. Should the fociety confider the inventor, David Charles, worthy of any renumeration, honorary or otherwife, it will be gratefully acknowledged by - Your obedient Servant, Wefimead, Jan. 1, 1803. JOSEPH HARDY. 4 Certificates MACHINE FOR LAYING EAND¢ 183 Certificates from Mr. Owen Edwards, of Brook; ‘and Account of a . a ah, machine for lay= Thomas Bynan, carpenter, of Weftmead, accompanied the ing Jand level, above letter, confirming the ftatement made herein. Defeription of the Machine for laying Uneven Land level, - invented by Mr. Davin Cuaries.—Plate XI, Fig. 1, 2, Fig. 1.—A, Part of the pole to which the oxen or horfes which draw the machine are faftened, and which is attached to the machine by a pin at B. _CC, The two wheels, fhod with iron, which run upon the axle D. © EE, The upper frame-work of the machine, extending _ from the axle to the extremity of the handles FF, and fecured firmly by the crofs pieces. _ GG, The curved iron fliders of the machine, which may be raifed or depreffed a little by means of the pins HH, which pafs through holes in the wood-work, and alfo in the iron fliders; thefe fliders form one piece with the back iron {craper I, in the manner more fully explained in Fig. 2. K, The wooden back of the machine, which fhould be made ftrong, to refilt the weight of the earth when colleGted therein, The iron {craper fhould be firmly fecured to this by {crews and iron-work. LL, The wooden fides of the machine firmly conneéted with the back and frame-work, in order to affift in colle@ting the earth to be removed. M, A ftrong crofs piece into which the ribs which fupport _ the back are well morticed. Fig. 2.—K, The interior part of the back of the machine. I, The iron feraper, fharp at the bottom, and firmly {crewed _ to the back of the machine. GG, Parts of the fide irons or fliders, fhowing the mode in which they are united with the fcraper I, M, The crofs piece above defcribed, Experiments ‘ \ 184 EXPERIMENTS ON MAGNETISM, ae Experimenis on Magnetifin; by Mr. Ritter, of Jena. Come punicated by Dr. OxstED, of Copenhagen*. The sah ata Tue phenomena of magnetifm have frequently been com- ol cemictty pared with thofe of ele@ricity, and many faéts feem to juftify have often bea the comparifon. Thefe faéts, however, are neither numerous ared, but : Ng ove want fase ChOUgh, nor fufticiently conclufive, to compofe a complete theory. A feries of experiments, exhibiting the magnetic needle in all its relations to eleétricity, at prefent better known by means of the pile, would undoubtedly throw much light on Ritter has infti- a fubject heretofore fo obfcure. Ritter felt the importance of tuted new inqui- : : hie : Sethe itt: fach an undertaking, and began frefh inquiries concerning jet. magnetifm, with the fame ardour and fagacity that have ever His experiments diftinguifhed his labours. ‘Though thefe experiments did not did not always always anfwer the full extent of his defigns, they notwithftand. anfwer, but ex-_ ee ; : Y i hibited many in- ing exhibit a fufficient number of interefting facts to excite the terefting facts. curiofity of every natural philofopher. A magnetic, Mr. Ritter’s firft experiments with the magnet were on wire, and an- frogs, He found that a magnetic iron wire, with another not other not mag- ; ; : Pes nes 5 netic, excited magnetic, excited a galvanic palpitation in thefe animals. Pre- inne Sasiet fently he obferved, that the fouth pole excited ftronger palpita- rate) J Ogs 5 5 5 : eS see tions, and the north pole weaker, than the iron not magnetic, more ftrongly, Ffaving conftantly noticed, that the metals moft fufceptible of the north lefs, hie ee Bitola - than iron not. O©%!dation excited the ftrongeft palpitations, he inferred, that magnetic. the fouth pole poffeffes a greater affinity for oxigen than fimple Hence he infer- ° d | t} le l { red, that the ron, an the NOE 0 pole leis. : fouth:pole hasa ‘This fuppofition he confirmed by means of feveral chemical asa? affinity re-agents. He placed a magnetic iron wire on pieces of glafs oroxigen ; the _ 2 > -o : = aes north, lefs, in a plate of earthen ware, and poured upon it very weak nitric ‘This confirmed acid, The fouth pole was attacked by the acid much more by expvriment. ieee iron powerfully than the north; and was foon furrounded by a de- te being ‘ pofition of oxigen, the quantity of which greatly exceeded that placed in wea . 5 Nitric acid, the of the other pole. fouth pole was The different oxidability of the magnetic poles is very well inherent exhibited likewife, by taking three {mall bottles of equal fize, of amagnetic filled with water, either pure or flightly acidulated, and putting wire being im- artis tla * Journal de Phyfique, December, 1803, Vol. LVII. p. 406. phial of water, into _ to depofit oxide, the unmagnetic iron a little after, and the EXPERIMENTS ON MAGNETISM. 185 into one the fouth polar end of a magnetic wire, into a fecond ie north pole 5 n - 7 5 E or o ne the north polar end of a fimilar wire, and into the third the end sihces wr 2 of an equal wire not magnetic: the fouth pole will firft begin end of a fimple ; Wire in a third 5 the fouth. pole north pole laft. This experiment requires confiderable care. firft depofits ox- The furface of the water muft be covered with very frefh oil ek of almonds, to exclude all accefs of air, Care muft be taken This expeii-_ too, that one of the bottles is not more expofed to the fun ™°"t requires ; : 5 i particular pre than the others, becaufe light accelerates oxidation. Ritter cautions. convinced himfelf of this by direét experiments ; expofing two ae be ex- . . ais . : cluded 5 iron wires in water to the fun, but covering one of the phials anq jigh: acces with black paper, when that in the phial left uncovered was lerates oxida- _ oxided much the more quickly. tion, If infufion of litmus be fubftituted inftead of the water in If infufion of Raps " : : - lit b the three phials in the preceding experiment, the relative Oxi- eee dations will be the fame; but they will be attended with a dations will be change of colour, fhewing, that an acid is produced propor- eel aah tional to each oxidation; fo that the fouth pole not only un- portion to each dergoes the greateft oxidation, but likewife reddens the infu- peti ap * r . . . cars fion of litmus moft*. The aétion that takes place in this ex- change of = periment is very feeble, and frequently requires a week or leur. es : ., This a€tion is more to produce a diftinét eff-& ; and indeed to accelerate it yery flow; “4 . o ? fo much as this, it is neceffary to add, previoufly to the infu- and to accelerate i i pany : : : ita {mall portion fion, as much acetic acid as will incline it to red, without haus ee completely changing its colour. ‘The infufion reddened in fhouid be added this experiment refumes its blue colour on expofure to the air: ° BiG inf adtons The infufion but we muft not hence. conclude, that the acid produced by thus reddened the aétion of the magnet is very volatile, ‘for infufion of litmus becomes blue reddened by phofphoric acid, or any other, exhibits the fie ve ta thon phenomenon. , but it is the The following experiment exhibits fome things peculiar, Ftp pe, and therefore I fhall give it more at large. It has not been other acid. repeated, but the harmony of its refults is in favour of its ac- Eonar curacy. Sixteen magnetic wires, of equal fize and power, were placed in fix veffels, all equally full of a mixture of one part nitric acid and thirty-fix parts water, in the following _* Ritter has remarked, that the oxidation of zinc, and feveral Ritter and Jager other metals, in pure water, produces an acid. Mr. Jager, a ce- have found, that Reeicd chyGei Pe ceuiteeee Hohe e roe “th the oxidation of lebrated phyfician of Stuttgard, made the fanie difcovery, without feyeral metals in knowing any thing of Ritter’s. pure water pro- duces an acid. manner ; 186 EXPERIMENTS ON MAGNETISM. In phialscon- manner: In the firft glafs were placed two. wires, one with passin ert the north pole immerfed in the fluid, the other with the fouth, x part, wereim- and not more than halfa line afunder: In the fecond, the fame," eek: * but the wires an inch and three quarters apart: In the third % qline diftance: and fourth were each three wires, with the fouth poles of all 2. the famet4 immerfed, but their diftances in the two glaffes different, as inch: 3- 3%. ; I i oles at Falines in the firft and fecond: In the fifth and fixth were wires fimi- 4. the fame at Jarly arranged, but with the north poles immerfed. Different 3 inch; a) < oy ie = Pe quantities of oxide were gradually depofed; and to exprefs tine: 6 the — the whole in few words, we will call the fouth pole S, the fame at 13. poe 1° : . wT ieekidonee north pole N, their greater diftance g, and their lefs p; and fitedin thefe | we will exprefs the order of oxidations as follows: SN g> with refpe’ ® SNpp 3Sp>3Se>3Npp>3Ngp>. On the nine- uan . p - tie fatlowicig teenth day it was obferved, that the lofs of fluid by evapora- order: No. 2). tion had not been equal in all the veffels, but took place in EE Aid >» aig the inverfe order of the oxidations. All the magnetic wires by evaporation, were weakened in power; N Sg leaft; N Sp more: of the a Se if. Wires 3S p, two had loft lefs power than the third; and in the oxidations. like manner 3Sg, 3Np, 3 Ng, had each two left’ more All the magne's powerful than the third; the ftrongeft were equal to N Sg. were weakened ¥ : : in power: No.2 In another experiment, where two little veffels filled with leaft; 1 more? infufion of litmus were employed, one of them containing two in all the reft : : , ; Z one wire was Magnetic wires, the fouth poles of which were immerfed in weakened more the fluid; the other two'fimilar wires, of which the oppofite than the others. "i ay 4 On immerfing Poles were immerfed; the oxidation was greateft in the latter two fouth poles yveffel *, tise Lafily, Mr. Ritter endeavoured to conftrué a battery of the latter were magnets, but he did not fucceed. For this purpofe he em- moft oxided. r , . Thee cea ployed a hundred and twenty magnetic wires, placed fo that ed unfuccefs- each pole had its contrary oppofite to it, and feparated from it fully to conftruct : i 5 4 iter with by a drop of water; but this apparatus produced no effeét. 120 magnetic The ingenious author, however, has not relinquifhed the hope ad = _ of being able to compofe a magnetic battery, though other ex- sp e€ ° . ~ Siseviah, cil periments, not lefs important, have hitherto prevented him, fepavated bya This feries of experiments he confiders only as the commences d f water 5 ; ‘i bathe hac nce ment of a very extenfive labour, the refults of which we hope given up the de- foon to obtain. fign: and means to purfue his in- ; 5 : . eds yp * This appears contradictory to the experiment adduced in the fubje& at large third paragraph. T. very extenfively. Obfervations ON ARSENIATED COPPER. 187 XI. Objercations on Arfeniated Copper. By Havy *. ‘Tue only ores of arfeniated copper which are well known, Hiftory of the are thofe from the county of Cornwall in England. The de- pes ‘hay termination of their trae compofition followed clofely on the compofition. dilcovery of this metallic fubftance, for which we are indebted to the fortunate chance which threw fome fpecimens into the hands of the celebrated Klaproth. It was in 1787 that he pub- lifhed in the Journal de la Socicté des Curieux de la Nature t, the refult of the examination which he had made of this new mineral. The authors who have fpoken of arfeniated copper fince that _ period, had only defcribed it under the form of acicular cryf- tals, when Citizen Lelievre, member of the Council of Mines, having fulpeéted the exiftence of a peculiar fubftance, from the infpeétion of a group of green hexagonal bevilled laminze " which were given to him, made an effay of it, and difcovered _ the prefence of oxide of copper and arfenic acid. Citizen Vauquelin foon afterwards confirmed this indication, and de- termined the proportion of the relative quantities of the two principles contained in ihe fame fubftance. About this time the opening of a fecond mine in the county of Cornwall occafioned the re-appearance of arfeniated cop- per, the vein which had been formerly explored being ex- haufted. This difcovery was the more important, as the fub- ftance appeared, in its new fituation, with charaéters altoges ther peculiar, and under forms hitherto unknown. M. de Bournon, who was at hand to participate in this in- ereafe of riches which refulted to mineralogy, fent to Citizen Gillet Laumont and me, feveral fpecimens chofen from among ‘thofe he poffeffed ; and that which added to the value of his “gift, was his hafte to communicate to us the interefting work “which he bad prepared, on the cryftailography of arfeniated “copper, before he publithed it. ; * Tranflated from a pamphlet in quarto, fent by the author to the Count de Bournon ; probably forming part of a journal. + Tom. VIII. p. 160. Mr. 188 Defcription of the varieties. ON ARSENIATED COPPER. Mr. Chenevix was employed at the fame time on the ana- lyfis of this {ubftance. Soon after they both publifhed the re- fults of their refearches in the Philofophical Tranfa&ions* ; and Mr. Chenevix teftifies his admiration at fuch a perteét agreement between two fciences which employ two metheds fo different to interrogate nature. M. de Bournon, on his part, fays that the analyfes of Mr. Chenevix have given the moft fatisfa€tory fanétion to the divifion which he had himfelf made, of the arfeniated copper into four diftin@ fpecies. Before going farther, it is neceffary to make known the va- rieties of arfeniated copper which I have been enabled to exa- mine. I fhall confine myfelf to giving a defcription of them, fuccin& and independent of the laws to which the ftruéture of cryftals is fubmitted, the actual ftate of our knowledge on this fubje& only admitting of hypothetical views, of which I fhall fpeak hereafter. 1. Obtufe o€tahedral arfeniated copper, (Plate IX. Fig. 2): incidence of P on p, 50° 4’; of P’ on p’, 65° 8’; of Pon P’, 139° 47’+. The colour of the cryftals is fometimes a fine ce- leftial blue, and fometimes a green, which varies between a grafs-green and a pale green. The o€tahedron fometimes be- — comes cuneiform, lengthening fo that the terminal edge is pas rallel at D. 2. Lamelliform arfeniated copper. In hexagonal laminz, whofe narrow faces are inclined alternately in contrary direc- tions ; the incidence of two of the narrow faces, fituated on the fame fide, on the correfpondent bafe, 135° nearly, ac- cording to M. de Bournon; incidence of the third on the fame bafe, 115° nearly. * For 1801, p. 199, et feq: + I adopt here, very nearly, the refults of M. de Bournon, wha indicates 50° for the incidence of Pron p, and 65° for that of P’on p’- I have only endeavoured to find limits capable of facilitating the calculations which I propofe to make. Let bac, gac, (Fig. 4) be the fame faces as P and P, (Fig. 2); let ao (Fig. 4) be the height of the pyramid which has its fummit in 4, (Fig. 2); oz (Fig. 4) aperpendicular to bc, and or perpendicular to cg :—if ao _ = 588, on = 2695, and or 1440, we fhall have 50° 4/ for the incidence of P on p (Fig. 2), and 65° 8/ for that of P’ on p's whence is deduced, by calculation, 139° 47’ for that of P on P’, The i ON ARSENIATED COPPER. 189 The laminz divide parallel to the large faces with great eafe. Their colour is a fine grafs-green. 3. Acute oétahedral arfeniated copper, (Fig. 3): Incidence of r on r’, 96°, according to M. de Bournon; of J on /’, 112°. The colour is a brown green. more or lefs deep. a, cuneiform. The preceding o€tahedron lengthened fo that the terminal edge is parallel tom. This form, which is the moft common, offers the appearance of a long rhomboidal prifm, more or lefs acute, and is terminated by dihedral fum- mits. 4, Trihedral arfeniated copper. Ina {trait triangular prifm, which is at the fame time equilateral, according to M. de Bournon. When the cryftals have not been long expofed, their colour is a fine bluifh green; but their furface is fubjeét to change and take a blackifh tinge. If they are {cratched, their primi- tive colour will re-appear. 5. Capillary arfeniated copper. This is properly the oli- ' venerz of the German mineralogifts. _ 6. Mammellated arfeniated copper. In mammellated mafles, firiated in the interior. Thefe two laft varieties are fufceptible of a great diverfity of tints, which flew the tranfitions from grafs-green to olive-green, to greenifl-brown, to tawny (mor- doré), to yellow, to bluifh, and to white, which is frequently fattiny. | The following is the manner in which M. de Bournon claffed M. de Bournon’s the different modifications which have been juft mentioned, ‘ification. according to the differences which they offer with refpe& to form, fpecific gravity, and hardnefs. He divides them, as I have faid, into four diftin@ {pecies. Four diftiné The firft is derived from the obtufe o€tahedron: the type of fpecies. the fecond is the lamelliform cryflal, in hexagonal laminz, with bevils inclined alternately in contrary direétions. He takes the acute o€tahedron for the primitive form of the third, and conneéts the acicular cryftals and mammelary concretions with if, as varieties: in the fourth he places the equilateral triangular prifm, and feveral other forms which offer the fame prifm, truncated on its folid angles or on its edges. On the other hand, Mr. Chenevix has given fix refults of Mr. Chenevix’s the analyfis of arfeniated copper, which I fhall detail, difpofing 294!y€s- them contormably to the order eftablifhed by M. de Bournon, Firft 190 ON ARSENIATED COPPER, Firft Species, in obtufé octahedra. Oxide of copper = ° a 49 Arfenic acid - - in a (ape Water - - - - 35 Lofs baad im 2 o 2 100 Second Species, in lamelliform Cryftals, Oxide of copper - 4 z 58 Arfenic acid - = 1 a2} Water - ° Ps be 21 100 Third Species, in acute oiahedra. Oxide of copper - - - 60 : Arfenic acid - - ON High Dic Lofs - - - - 0.3 100.0 Variety of the fame Species, in capillary Cryftalse Oxide of copper = a ¢ sy Arfenic acid == - 2 = | 8 Water - Be oe - - 18 Lofs = - ~ Si 100 Another Variety, in mammellated Concretions. Oxide of copper = - - 50 Arfenic acid - ~ - - 29 Water - - = - 21 Fourth Species, in trihedrat Prifins. Oxide of copper = * “ 54 Arfenic acid - - - - 30 Water « - “ Re 16 100 Towards. } ON ARSENIATED COPPER. 191] Towards the conclufion of his memoir, Mr. Chenevix re- Only one true _ marks that the natural arfeniate of copper exifts in three differ- Sean we ent combinations, the firft of which contains 14 per cent. of are arfeniates of _arfenic acid, (firft refult above); the fecond contains 21, (fe- ag beh cond refult); and the third 29, (third, fourth, fifth, and fixth refulis). Itis true, the third refult gave 39.7 of acid in the 100 parts, but as the remainder of the mafs was compofed of _ 60 parts of copper without water, he found that the propor tion of the acid with the copper did not differ much from that _ which takes place in the varieties in which water forms a part: _ this induced Mr. Chenevix to comprehend this refult in the fame divifion. Yet he confiders this combination as the only _ true arfeniate of copper, while the other three are arfeniates of hidrate of copper. I feel the value of the double work from which I have given this extraét fo much the more, becaufe, having read the me- moirs which contain the developement, I am enabled to judge _ of the advancement which it has produced in our knowledge on a fubje& which was ina great meafure new when MM. de _Bournon and Chenevix began to be employed with it. The _ expofition which fhall add of fome enquiries I have made on - the cryftallization of arfeniated copper, and of the refle@tions which they have given rife to, have no other objeé but that nothing may be negleéted which tends to elucidate in a greater degree, every thing conneéted with an obje& of fuch import. ance as the diftinétion of mineralogical {pecies. __ After having read the cryftallographic part of the work in Can the varies ~ queftion, I was defirous to know if it was not poffible to bring ale oe ie fome of the cryftals, defcribed by M. de Bournon as belonging form 2 : _ to different {pecies, to the fame form of the integrant molecule; but not being able to make all the direé&t obfervations which would have guided me in this enquiry, I was obliged to con- - fine mylelf to fimple hypothefes. _ I therefore confidered the obtufe o€tahedron as performing the funétions of the primitive form; and I was the more ware ranted in conceiving this opinion, becaufe the celebrated Kar- ‘ften, in a fupplement to the excellent memoir which he had _ publifhed be‘ore *, on the combinations of copper with differ- ent principles, fays that the o@tahedron in queftion is lamellated, a 2 % Journ. de Phyfique, Brumaire, An. X. p- 342, et fuiv. in 102 ON ARSENIATED COPPER. Comparifon of in-a direétion parallel to the faces of the two pyramids, of which pesmi itis the aggregate*. Proceeding)on this datum, I was curious drae to know if it was not poffible to conneét with the form of the obtufe oGtahedron in queftion, that of the acute o€tahedron, which M. de Bournon has taken for the type of his third fpecies. Let P, P’ (Fig, 2) be ftill an obtufe o€tahedron, in which the incidence of P on p is reckoned to be 50° 4’, and that of P’ on p’, 65° 8’, conformably to the meafures indicated above: if we imagine another o¢tahedron (fig. 3) the fign of 2 4 iim . - we! fall ‘Gad’ Giat the incidencever Menge Le 109°, and that of r on r’ is 93% 36’. Now the correfpondent incidences determined by M. de Bournon, are one 112°, and the other 96°; which in one cafe makes a difference of 3°, and in the other of 2° 24’, The differences If the meafures had been taken on cryftals fo well defined, ech ac- that the differences could be confidered as real, we muft have concluded that they formed two diftin@ f{pecies, becaufe even _ thefe differences could only have been done away by fuppofing the laws of decrement to be much too complicated to be ad-' miffible. J But if the cryftals were not capable of very accurate meafure- \ ment, we can the better conceive that the differences were fimply apparent, and that it may be poffible that the error did not wholly arife in one obfervation, fince it was neceffary to — make two, in which fmall deviations might have been pro- — duced on oppofite fides; and then mechanical divifion alone, — by giving different refults with refpeét to the two oétahedra, — | would have fhown that a conformity between the angles ob- ferved and thofe meafured, would be purely accidental. Comparifon of variety with the ahtdke eaieha. fame o€tahedron with obtufe fummits. Now, if we fuppofe © dron. two interfeéting planes, parallel to the face P’, and which meet the center, they will detach an oétahedral fegment which can-— not be fuppofed to have much thicknefs, and whofe two large faces will be hexagons, and the fix lateral faces, trapeziums, * Fourn. de Phyfique, Pluviofe, An. X. pe 13]- inclined. I aflerwards compared the lamelliform variety with alternate 4 the lameliiform bevils, which is the fecond fpecies of M. de Bournon, with the — ~ ON ARSENIATED COFPER, inclined: to the great faces *. But thefe trapeziums will not be fituated alternately in oppofite dire€tions. The, three which will form obtufe angles with the large faces, will be contiguous to each other, and the fame will be the cafe with thofe which form acute angles with the fame faces. For example, thofe analogous to P’, will cotrefpond to the two faces of the adja- cent o€tahedra at B, B’, and to the face fituated behind 4, _ parallel to P. The inclination of this latter face on P is, ac- cording to M. de Bournon, 115%; and the two others, as I have indicated them above according to my calculations, are each about 1391°. Now, of the three lateral trapeziums in the lamelliform ar- fenical copper, one has the fame inclination of 115° on this 'bafe, according to M. de Bournon, and the two others have 135°; an eftimate which he only gives as an approximation, _and which only differs by 43° from that corre{ponding to it in the obtufe oftahedron, fits 2). _. The great difference confifts in this, that the three lateral _ trapeziums which look towards the fame bafe, in the o¢tahedral _fegment I have defcribed, are contiguous to each other, as I have faid; while thofe of the lamelliform arfeniated copper valternate with the three others which look towards the oppofite bafe +. _ But there is a method of removing this difficulty. Let us _ conceive that the two feétions made in the oétahedron (Fig. 2), _ inftead of being parallel to the face P’, are fo to the face P. In this cafe the lateral trapeziums, fituated on the two fides of _ the edges B, B’, will always have an inclination of 1394° to the fuperior bafe. Now, if the fegmdnt parallel to p pales an angle of 115° with the bafe analogous to P, the three feg« \, ments will preferve, with refpeé to thofe turned towards the - oppofite bafe, the alternation indicated by M. de Bournon, et & * Several fubftances, among others the fpinelle, offer examples ~ of fimilar fegments. + The figure given by M. de Bournon, of which that is a copy Bin Plate XI. Fig. 5, feems to have been traced aceording to the " eondition that the three trapeziums turned towards the fame bafe fhould be contiguous. This was doubtlefs an overfight of the _draughtfman. . Von. VIII.—Jury, 1804 Oo But of the trapeziums which form obtufe angles with the large face. 193 194 ON ARSENIATED COPPER. But the incidence of p on P gives, on the contrary, an acute angle of 50°. Now, let us imagine a decrement indicated by — ,D, which aéts on the face p and on that which is oppofite ; the faces produced will be fituated vertically ; whence it follows that that which will maik the face p will form an angle with P equal to 90° plus 25°, which is the half of the inclination of p to P, that is to fay, the angle in queftion will be 115°, con- formably to obfervation *, Their divifion I fall not urge thefe refults farther, which, as I have already into four fpecies fated, I only offer as purely hypothetical ; and I fhall abftain is not admitted - =e Z by the laws of from adding my opinion with refpeé to the fourth of the fpe- ftructure, cies admitted by M. de Bournon, which, according to him, has the equilateral triangular prifm for a primitive form. It is enough for me to have fhown that, with refpe@ to the divifion of arfeniated copper into four diftinét fpecies, the laws of the ftruéture may give rife to doubts which deferve fome attention. — If they can be removed, as it is not impoffible they may, an- § other proof will be obtained in favour of an opinion on which no obfcurity fhould remain, that it may be worthy of being una- i nimoufly adopted. Comparifon of If we now confider the refults of the analyfes which Mr. _ Mr. Chenevix’s Chenevix has made of the different modifications of arfeniated . lyfes and M. ; de Boieana's di- Copper, we find, that in fuch of thefe analyfes as have had for vifion. their objeét the types of the four fpecies admitted by M. de f Bournon, three have given fenfible differences in the relative _ quantities of copper, arfenic acid, and water. Thefe analyfes — correfpond with the firft, third, and fourth {pecies. Another — analyfis, made on the fecond fpecies, gave only copper and | arfenic acid, without water. Thus, fuppofing that the rela- tions between the quantities of the three principles contained © 7 * I have a lamelliform cryftal, on which, inftead of a fimple — bevil, there are two, fituated in contrary direétions on the fides of _ the fame edge; but they are too {mall for it to be poflible to deter- — mine the pofitions exactly, 4 analyfis Wu in the modifications which Mr. Chenevix calls arfeniates of ii | hidrate of copper, conftitute true limits, and that; in the mo- j | dification which he calls fimply arfeniate of copper, the abfence of water depends on the nature of the fubflance itfelf; we fhall, in this refpeét, find an agreement between the refults of _ tas " i ON ARSENIATED COPPER. 195 analyfis and thofe of cryftallography, very favourable to the fubdivifion of the mineral in queftion, into four diftiné fpecies. But Cit. Vauquelin, on analyting a piece of lamelliform ar- eh eee feniated copper, whofe cryftals were quite frefh, obtained a cleat a een very different relation between the quantities of the three prine feniate : ciples*. His refult was as follows: Oxide of copper = ° 2 39 Arfenic acids. - - - 43 Water “ 2 = = 17 Lofs - = = = 1 100 It is remarkable in this cafe, that the quantity of acid ex- _ceeds that of the copper, while in the refult obtained by Mr. Chenevix it forms only a little more than a third of the quantity of copper. It is not therefore evident that the limits indi« cated by this celebrated chemift are effential to the fubftances analyfed. __ The experiments of the fame philofophers on the capillary and of the cas eryftals, offer differences not lefs ftriking. According to Cit, Pilary cryftals. Vauquelin thefe cryftals contain, * Mr. Chenevix, in his memoir, gives a paffage from a letter which Citizen Vauquelin had written to him, and in which he in- formed him, that having analyzed cryftals of the lamelliform va- riety, he found that they were compofed of 59 of oxide of copper . and 41 of arfenic acid. Mr. Chenevix adds, that the great differ- ence between this refult and that which he had himfelf obtained from the fame fubftance, induced him to repeat his analyfis with great care and attention, and that he conftantly found the fame proportions of oxide of copper, arfenic, and water. It is very probable that this refult announced by Cit. Vauquelin, and fo dif- ferent on the other hand from that now given, was obtained in a - firft effay, or that this chemitt, when he wrote to -Mr. Chenevix, trufted to his memory, which was not fo faithful as it generally iss However that may have been, the only refult avowed by Cit. Vau- quelin is that we now publifh, and which he has inferted in the ‘Fournal des Mines, No. 55, p. 562. 02 Silex 196 Klaproth’s ana- lyfis. Mr. Cheneviws refults do not agree with of thofe of M. de Bournone. ON ARSENIATED COPPER, Silex 4 = = = 2 Water - - " tvs Arfeniate of iron - -— = 7 to 8 Arfeniate of copper - a Au86 100 This chemift adds, that if the arfeniate of copper did not contain any foreign matter, it would be formed of about 69 parts of oxide of copper and 31 of arfenie acid. We have another refult on the fame fubje&t, obtained by M. Klaproth, whofe labours have concurred fo advantageoufly with thofe of Vauquelin, to. procure an exaét knowledge of ‘the compofition of minerals. His refult gave, Oxide of copper - ° 50.62 Arfenie acid - - - 45.00 Water - - ~ - 3.50 Lofs = - = = 88 100.00 #* The quantity of copper is nearly the fame as in Mr, Chene- vix’s refult; but on one fide we find 45 of acid with 3.5 of water, and on the other only 29 of acid and 18 of water; which is very different. Befides, we need only keep to Mr. Chenevix’s own refults to find difficulties and caufes of uncertainty; for while this eclebrated chemift obtained a very fenfible quantity of water — from the capillary cryftals and the mammellated maffes, thefe — two modifications were confidered by M. de Bournon as fimple varieties of the third fpecies, which is the acute o@tahedron, and which gave only copper and arfenic acid without water. Further, if the analyfes of the capillary cryftals and of the © mammellated maffes, are compared with that of the cryftals in tribedral -prifms, it will be feen that the differences do not exceed thofe which are frequently met with between the ana- lyfes of feveral pieces which evidently belong to the fame {pecies of mineral, Tadd, that M. de Bournon feems to have had more aue - thority for confidering the capillary cryftals and the mammel- * Additions a la Connoiffance chimiques des Minéraux, p. 192. lated ' ON ARSENIATED COPPER, 197 Jated concretions as fimple varieties of the acute oftahedron, fince he indicates the intermediate modifications which con- neét thefe varieties with their type; fo that, according to him, there are cryftals which are perfeétly determined in one part of their length, and fibrous at their extremity. M. de Bournon, doubtlefs ftruck with the exception which A fifth fpecies the agreement between the two f{ciences, announced by Mr. ala Chenevix and himfelf, feemed liable to, in this inftance, has fince inferted in Mr. Nicholfon’s Journal * a note, in which he propofes to eftablifh a fifth fpecies of arfeniated copper, compofed of the capillary cryftals and mammellated maffes, which feems to operate lefs in removing the difficulty than in bringing it to light. It cannot be denied that the modifications of arfeniated cop- External differe per offer fenfible differences in their afpeét, their exterior ie forms, and their colours. M.de Bournon alfo indicates fome alone as evidence in their hardnefs and in their fpecific gravities. But the of 4 different, reduction of natural beings to the fmalleft poffible number of nae fpecies, really diftinét, is an advantage of fuch value to {cience, which it perfeétionates by fimplifying it, that, before feparating fubfiances, according to thofe diverfities which feem to be at variance with the relations which they otherwife have, and be- fore feeking particular fpecific names for them, which would be neceflary, all the means of afcertaining that the diverfities in queftionare not purely accidental, fhould be exhaufted. Even though the refearches which ftill remain to be made for the accomplifhment of this objeét, fhould have no other effeét but to caufe the difappearance of one fingle fpecies, admitted by the two celebrated men whofe refults I have fet forth, from the fyftem, they will not be unprofitable to the progrefs of mineralogy. ** A reply communicated by the Count de Bournon will appear in our next. j * Philofophical Journal, new Series. Vol. VII. p. 577. Objervations 198 @N FLUIDS AS CONDUCTORS OF HEAT. XII. Objfervations upon the Doérine of Count Rumford refpeding the want of direéet conduéiing Power in Fluids, with regurd to Heat. Sy Cit. BERTHOLLET. (Concluded from page 140.) Nicholfon, it AM of opinion, that the experiments of Nicholfon, of ates and Thompfon, and of Murray, leave no doubt on the com- urray have Vey fs k : ch ae proved, that heat munication of heat between the particles of liquids: fome of pafiés throush them fhow that the motions of the folid corpufcules which the particles of d : ab ae ‘ 3 fluidgs thatcur. are agitated in a liquid, may often miflead, with refpeé to rents are often the currents which are believed to be perceptible: but their Pate exiftence muft not, for this reafon, be denied, when a dif- in conduéting ference between the fpecific gravities is fuddenly eftablithed, a: and when the’ heat is communicated at the lower part of a veflel. The others prove that the communication of heat may be made through a liquid in which no current can be fuppofed to tranfport it immediately toa folid body, and they prove that liquids are poffeffed of a conduéting faculty which differs in its intenfity; but it is not to be inferred from this, that the locomotion of the particles of liquids does not con- tribute to eftablifh an equilibrium of temperature more {peedily : it is even probable, that the latter effe€t is generally the reateft. , Thefe general The foregoing confiderations, into which I have admitted role a for the application of the faculty of communicating heat common peas, “ to all bodies, of the conduéting difference, and of the more f{peedy diftribution of heat by means of the difference of the {pecific gravity which it introduces between the particles of a fluid, feem to me to account for all tne phenomena which the . difcernment of Rumford has made public. That gafes re- Thefe confiderations lead me to an opinion very different ceive heat very from his; it is known with what rapidity the thermofcopes, rapidly, is feen aie A some : in the expanfion OF air thermometers, indicate the variations of temperature : of air ther- Piétet could not obferve a fecond of difference between the mom‘ ters and z J JOS 6, . air balloons, elevation of a thermometer of this defcription, and the emanation of radiant heat by a body placed at a diftance: it has been obferyed, that aeroitats experience a fudden dilata- tion ON FLUIDS AS CONDUCTORS OF HEAT. 199: Yion by the appearance of the fun*; thefe phenomena feem to me to indicate that the elaftic fluids, far from being bad conduors, on the contrary, receive the temperature of other bodies very quickly; for, can it be fuppofed that all the particles of the gas take the temperature which they acquire by the contaét of the covering of the balloon alone, and how can it be conceived, that the lower particles, which are con- tiguous to that portion of the covering which does not receive the folar emanations, fhould be carried towards that which is ex- pofed to it? And fince thefe particles at each contaé& only receive a part of the temperature to which they attain, what @ prodigious whirlwind muft .there be fuppofed to be in the fas!) It appears to me, that the elaftic fluids, inftead-of being The flow eon- bad conduétors, poflefs this property in a high degree, al- Rei ~ though they probably differ from each other in this refpeét ; cribed to fome- and if air which is confined produces effeéts which feem to modification. prove the contrary, they are owing to fome circumftance which modifies this property. I think it is probable, that this circumftance is the ftate of The gas is pro- compreffion produced in a gas which cannot acquire a dilata- ratte prewentes . Z 2 5 rom acquiring _ tion fuitable to the temperature it receives ; we have feen that heat, becaufe it caloric, in combining with the gafes, only raifes the tempera- cannot expand in ture becaufe the dilatation meets with an obftacle (107); "* — hence it refults, that the further the air is removed from the ftate of dilatation, which it fhould have, to be in equilibrium of temperature, the greater -refiftance will it oppofe to the combination of the caloric, and the more will it lofe of its condudting faculty, fo that the air which would take the temperature of the furrounding bodies with facility, if it could acquire fuitable dimenfions under a given preffure, becomes a worfe and worfe condudtorin proportion as it re- ceives a temperature farther removed from the dimenfions which it can take. The air then experiences an effect, which __ may be compared to that of a body in which the force of cohefion obfruéts the aétion of a liquid, which can effeét its folution as foon as this obftru€tion begins to be diminifhed. This explanation is applicable to the confervative property The effeé of of heat, which Rumford has proved to belong to the air eho which adheres to particles, fuch as thofe of the eider-down ; prevent the currents, than t@ * Defcrip, de l’acroftat de Acad. de Dijon. oppofe the ex~ this 200 ON FLUIDS AS CONDUCTORS OF HEAT. panfion by its this air only adheres by a true affinity, which probably reduces pil Be ot its dimenfions, or at leaft, oppofes its dilatation; and if the adheres to it. water can drive it off, it is only becaufe it combines with thefe fubftances, and adheres to their furface by its affinity ; fo that the air will then experience the fame effe@ from the action of the affinity of the bodies to which it is adherent, as is produced on its elaftic effort, by the fpace within which it is confined, and in which it receives a higher temperature without having the power to dilate. So that elaftic Thus the elaftic fluids which dilate much more by a fimilar fluids being more change of temperature than liquids and folids, muft have the alterable in their ; : é : volume, are correfponding faculty of entering more eafily into combina- aifo more difpofed tion with caloric: they offer but Itttle refiftance to compref- to give and take 5 ; : heat, fion; they heat by the redution of their volume; and they cool when they dilate: do not thefe effeéis announce a great difpofition to combine with caloric, or to abandon it, and to receive different degrees of faturation from it? and never- thelefs, according to the opinion of Rumford, there muft be an infurmountable barrier between the moft diftant tempera- tures, of the different particles of a gas, when the particles do not meet with a folid body. The fame doce It is poflible, that liquid fubftances may be much better trine applied to calculated to conduét beat than when they are ina folid ftate ; liquid water: Sudden accumu- the properties of the reciprocal affinity which produces cohe- lation or abforp- fion, feem to point this out: for fince this affinity oppofes the tion by its fon} dilatation, it will offer an obfiacle to the combination of the better than ice, caloric: this refiflance to its introdudtion 1s alfo proved by the &c. guick accumulation which is made of it, as foon as the force of cchefion is deflroyed, fo that it is oppofed to the com- bination of caloric, as well as to that of other fubftances; in faGt, water feems to take the common temperature more eafily, independent of the locomotion of its particles, than ice, which is a very bad conduétor, and it is perhaps from this difference, that ice, and all the folids which pafs to the — liquid ftate, liquefy at the furlace, inftead of taking the — common temperature. zi e I only offer thefe laft Reach as conje€lures, which may invile to experimental enquiries on a ek end which is not indifferent to chemical theory. AM emoir MOTIONS OF FLUIDS. gO) XIII. A Memoir on the Movements which certain Fluids receive from the Contact of other Fluids*. By J. DRapaRNaAvuD, Curator and Profegor of Natural Hiftory, at the Medicinal School of Montpelier. I HAD obferved that alcohol attacks, and finifhes by even, Experimenton “k F ; the aétion of at length, deftroying the calcareous covering of the mollufcz, aicohol which which are put into it to be preferved. Suppofing that this led to the dif- might arife from the alcohol, particularly that which is not ae well rectified, containing a little acetous acid, I puta little tinGure of turnfole into a glafs capfule, and poured into it a a few drops of alcohol. The tin@ture did not change colour, but to my great furprife it moved towards the circumference with great vivacity, leaving the bottom of the capfule un- covered : when it had reached the maximum of difperfion, it returned again, and covered the bottom of the veffel which it had abandoned. It is evident, therefore, that mifling what I fought, I found that which I did not feek, which frequently occurs in the courfe of experiments. - This curious experiment induced me to make a multitude Prevoft’s a of others, and to try a great number of fubftances. At the MSP ee moment of putting thele experiments in order, and of com- odorant bodies. pofing this memoir, I recolleéted having read that MW. Beneaz& Prevoft had produced this repulfion of water by means of volatile oils, and even of many folid odorant bodies. I there- fore confulted the two memoirs which this ingenious phi- lofopher has inferted m the Annals, and whofe fubjeét is, The methods of rendering the emanations of odorant budies fenfible to the fight +. Although my experiments were made with another view, 1 pafs over, in filence, all which are conformable to thofe of M. Prevoft, and which I made by employing the fame fubftances: I fhall only {peak of thofe which differ from his, either in the refults obtained, or in the means employed. 1. If a thin ftratum of water is put on the bottom of a Aétion of alcohol veflel, and a drop of alcohol is brought to the centre of this °" ““*™ * From the Annales de Chimie. Fruétidor, An. XI, + Annales de Chimie, Tom. XXI. et XXIV. ftratum, 202 MOTIONS OF FLUIDS. ftratum, with a glafs rod, the water flies in an inftant with vivatity, leaving the bottom of the veffel uncovered; when it has reached the maximum of difperfion it returns, and covers again the bottum of the veffel which it had quitted. Difk of difpere = 2, I call that part of the veffel which is abandoned by the a water the di/k of di/perfion. In the preceding experiment, this difk thows a perfeét drynefs and all its natural polifh. The repititionof 3, Thewepulfion becomes lefs confiderable, and the difk of the experiment 4i(perfion fmaller, it tion as the experiment is repeated leffens its peter r, 1n proportion P Pp eficcts. in the fame water., This arifes from the water becoming gra- dually faturated with alcohol. Influence of the 4. The nature of the veffels has’ no influence on the preced- “i ing experiment, nor on thofe which follow. They take place equally in veffels of porcelain, earthern ware, glafs or . metal. 5. The form of the veffels has much influence on the fecond period of the phenomenon, that is to fay, on the return of the water, and on the difappearance of the difk of difperfion. If the veffel is a little concave, the water always comes back, and covers the bottom of the veffel again. It will be obvious, that this is the neceffary effet of its gravity. If the veffel is flat, the water only returns when the difk of difperfion has not atiained too great a diameter. If the bottom of the veffel is a little convex, the water does not return after having been difperfed, and it moft be evident, that to do fo it would aét contrary to the operation of its own gravity. Motion of the 6. Being defirous to render the obfervation of the motions expelled fuid; of the expelled fluid eafier and more perfeét, I fubftituted tin@ture of turnfole, which, as is known, is only water coloured by turnfule, for pure water. The refults were the fame, but much more fenfible; and I could then readily diftinguifh an undulating or trembling motion on the internal edge of the water which furrounds the difk of difperfion; a motion which proves the continual emiffion of the alcoholic particles againft this interior edge, and determines the removal of the water. and of the im- 7. But to complete the proof of the explanation which I pelling fluids ave juft given of the phenomenon, it was alfo neceflary to render the motions of the impelling fluid fenfible : I fucceeded by ae MOTIONS OF FLUIDS. 203 by an analogous procefs. I coloured alcohol by means of turnfole ; with this {ubftance it takes a very beautiful colour which is not at all fimilar to the violet blue of tinéture of turn- fole, but, on the contrary, is of a very vivid blue, analogous to that of indigo, or pruffian blue. I then wetted the bottom of a plate with pure water, and, with a glafs red, brought a drop of this coloured alcohol to the centre: the water was driven back with vivacity. In the centre of the difk of dif- perfion was a blue {pot, formed by the coloured alcohol, and the reft of the difk was white like the bottom of the plate. But the proof of the aétual continual emiffion of the coloured alcoholic particles, is that as the water retired, its internal edge, which touched the difk of difperfion, became more and more of a violet colour, analogous to that of tinéture of turn- fole prepared with water. It is evident, therefore that in natural philofophy, faéts are explained by faéts, and, that this experiment confirms the confequence | I had deduced from the preceding experiment. 8. If the plate is wetted with the alcohol, and a drop of Water does not water is put into the centre, the alcohol does not experience ee ee any motion; the drop of water flattens, it retains its orbicular form for fume moments, at length it finifhes by {preading irregularly, mixing with the alcohol, and uniting with it. 9. If the bottom of the plate is covered with a very thin Oil is repelled ftratum of olive oil, and a drop of alcohol is brought to the oe centre, the oil is repelled, though more flowly than the water on account of its vifcofity, and the bottom of the plate is left dry. - If the ftratum of oil is too thick, it will not quit the bottom of the plate, and the expanfive-motion of the alcohol takes place only on the fupertices of the oil. 10. If a morfel of the frefh rind of lemon or orange is The effential oil placed in the centre of a wetted plate, the water is fenfibly ee 4 repelled, and the difk of difperfion is agreeably tinged with duces ee the prifmatic colours, which depends on the difengagement of >¥t weaker. the effential oil. But this motion has not nearly fo much in- tenfity as that produced by means of alcohol. 11. Convinced by the preceding experiments that every The affinity of volatile fluid at the aimofpheric prefiure, was capable of pro- eee ducing this repulfive movement, I employed liquid ammonia, jts BR pha I therefore wetted the plate in the ufualmanner, and brought action, a drop 20k MOTIONS OF FLUIDS. a drop of volatile alkali to the centre. What was my furprife to obferve, that the flighteft motion was not manifefted in the water; I however fufpeéted the caufe, and believed that this apparent anomaly was owing to the ammonia, which, having a very great affinity with water, combined with it at the inftant of their contaét. which was ex~ 12. Lrefolved, therefore, to fubflitute a fluid to the water, ees in olive which had lefs affinity with ammonia, and I chofe olive-oil, which I had at hand. I again covered the bottom of the plate with a thin layer of this oil, and brought a drop of the ammonia to the centre: the oil was inftantaneonfly repelled, as it had been by the alcohol. Ammonia does 13. If the plate be wetted with alcohol, and a drop of mot repel alcohols - smagnia is’ put into the centre, the alcohol is not repelled, the drop of ammonia flattens, and the two liquors evaporate. I thought I perceived a flight tremulation on the edge of the drop of ammonia. but alcohol re- 14. If the plate be wetted with ammonia, and a drop of pelsammoniae alcohol is brought to the centre, the ammonia is repulfed like pure water. It appears, therefore, from this experiment, and the preceding, that the horizontal or lateral force of ex- panfion of the alcohol is fuperior to that of the ammonia. Olive-oil and 15. A drop of olive oil put into a wetted plate, did not water have no . 2 ; repulfive a@ion. produce any motion in the water. It was the fame with water beat up with oil to the confiflence of anunguent. MM. Prevoft, in his memoirs, feems to announce refults obtained with the fixed oils, which are contrary to my experiments, and par- ticularly to thefe. I fhall not enlarge farther on experiments which fome may, perhaps, think more curious'than ufeful. But when the at- tractive powers of yellow amber, or of the loadfione were firft obferved, neither their importance, nor the aftonifhing | difcoveries to which they have fince led, were {ufpeéted. MBALVANIC AND ELECTRICAL EXPERIMENTS; 905. r XIV. Leiter from Mr. Cutusertson refpecting his Galvanic and Ele&rical Experiments. To Mr: NICHOLSON. Dear Sir, In confequence of the note which you have been fo obliging Introduction, as to add to my letter, addreffed to Dr. Pearfon, inferted in _ your Journal for this month, I have to fay, that the troughs _ were ufed collaterally: I fhall now be happy to fee your re- _ marks. It appears, that I ought to have been more explicit, _ and therefore, I beg leave to offer the following additional obfervations *. | The two Jaft mentioned experiments in the letter alluded to, were compared with common eleétrica! difcharges, with a view to prove what quantity of coated glafs would be re- quifite to ignite the famelengths of wire. Two jars, each containing about 170 fquare inches of coated ‘Experiment geration of furface, were fet to the Aah divane of a 24 inch fingle plate wire by jarse ele€trical machine, with my univerfal BicvGuicter loaded with 31 grains, (fee Quarto Journal, Plate XXII. Vol. II.) * I ought certainly to have mentioned the arrangement of the troughs, and likewife I ought not to have faid fo vaguely, that double quantities of galvanic fluid, only burn double lengths of wire, becaufe I am ftrongly of opinion, that the reafon why gal- vanic difcharges from troughs do not aét upon metals in the fame ratio as common eleétric difcharges do, proceeds from fome defect in the arrangement, and alfo conftruction. _ I find in my notes of improvements for the 6th of June, 1903, Pile of large that I had madea pile of 16 pairs of plates of 10 inches diameter, ey and that eight of them laid upon each other in the ufual manner, with cloths wetted with diluted muriatic acid, burned one inch of wire of 1-195th part of an inch in diameter, and that 16 pairs burned four inches of the fame wire. This experiment was re- peated on the 8th of June, with the fame refult, with refpe& to metals, but gave ftrong and loud fparks from metal to metal, fuf- very loud gal- " ficient to be heard at 300 yards diftance, which refult, I believe, Vic fparkss has never been obtained from troughs, foas to be heard, indeed, at any diftance. For the laft experiment, the cloths were wetted in a ftrong folution of muriate of ammonia. ’ | Eight FELL ELPA a a 2906 GALVANIC AND ELECTRICAL EXPERIMENTS: Eight inches of the fame fort of wire were laid in the circuit, 57 revolutions of the plate caufed the eleétrometer to dif- charge the jars which ignited the wire perfeétly, as in the ninth experiment. Then fix inches of the wire were laid in the circuit, and the above nnmber of revolutions caufed the difcharge, the wire being deflagerated and fufed into balls — in the fame manner as in the eighth experiment. Deduétionas to Hence I conclude, that 340 fquare inches of coated glafs eee properly conftruéted, will bear a charge equal to a galvanic jarandapile. battery of 1080 {quare inches of furface. Probability that The refult of the above experiments gives me reafon to pd ees think, that there is a miftake refpecting the diameter of the than ftated. wire ignited by Mr. Wilkinfon’s batteries, as mentioned in your Journal, Vol. VII. p. 297, to which you refer, becaufe to ignite one half inch of fteel wire of one feventieth of an inch in diameter, will require a power fufficient to ignite 120 inches of wire ~1, part of an inch in diameter, by common eleétrical difcharges, which is a power equal to two of my common eleétrical batteries, {fee your Quarto Journal, Vol. II. p. 525.) The greateft power of 60 pairs of 6 inches fquare plates that ever has been known, was that of igniting 16 inches of wire of -15 part of an inch in diameter. Mr. Wilkinfon’s trough of 100 pairs of plates of 4 inches fquare is of much lefs furface, and as he fays, it is a lefs favourable fize, from which, and from the above experiments, 1 conclude, that fuch a battery has not the power of igniting one half an inch of wire of one feventicth of an inch in diameter, unlefs galvanic difcharges aét upon metals in fome manner different to common ele&trical difcharges, but with which I am unacquainted ; perhaps Mr, Wilkinfon he be kind enough to clear up this remark, oJ Iam, with due refpeét, Dear Sir, Your very humble Servant, JOHN CUTHBERTSON, ‘ Poland Street, Soho, dune 19, 1804. Chemicaé EXAMINATION OF THE OCHROITES. 207 XV. Chemical Examination of the Ochroites, a Mineral not hitherto well known, containing a New Earth. By Kuaprotu*, Tue foffil which forms the fubjeé&t of the prefent analyfis, Hiftory of the and to which I have given the name of ochroites, for reafons ye to be ftated hereafter, is found in the mine of Bafnztes, near Riddarhytta in Weftmannland. The firft account of this mineral we owe to Cronftedt, who Firt noticed by furnithed: a defcription of it, together with that of another Cede mineral, found at Bifpberg in Delecarlient. Scheele con- fidered both as fpecies of iron ores, and gives to them the name of lapis ponderofus, ponderous ftone, (fchwerftein) or tungften, which he defcribes in his mineralogy as terrwm ealciforme, terra quadem incognita intime mixtum t. He like- and examined by wife examined this tungften, and made us acquainted with en its true nature. The mineral which he examined, was, however, the pearl-coloured tungften of Bifpberg, and from this he concluded, that the examination of the tungften of Riddarhytta was neceffary, confidering it a mineral of the fame nature, he diftinguifhed it by the name of reddi/h tung fien. Soon afterwards D’Elhuyar analyfed both minerals, he and D’Elhuyar. verified the analyfis of thé true tungften, but proved that the conjecture of Scheele concerning the other, mineral was founded in error; the refults of his analyfis fhowed that the foffil known by the name of reddifh tungften, was compofed of 54 parts of lime, 24 of iron, and 22 filiceous earth. From what follows, it will, however, become obvious, that this mineral contains neither lime nor tungften, but a new earth hitherto unknown. External Charaéers of the Ochroites. The colour of this mineral is between carmoifin red, clove- External chae ‘brown, and reddifh-brown. It is compaét, breaks, fplinter-*a“ters of Ochroites. * Gehlen’s new Journal of Chemiftry, Vol. II. part. iii. p. 303. _+ Tranfations of the Swedifh Academy of Sciences, 1751. p. 235. t And alfo in Cronftedt’s Mineralogy by Magellen, Vol. I. p. 46. é ing | 208 Analyfis of the Ochroites. EXAMINATION OF THE OCHROITES, ing in irregular, not very fharp or angular pieces. It is perfeétly opaque. Its powder is reddifh-gray. It is not very hard, but brittle, and very ponderous, Its fpecific gravity is 4,660. Cronftedt ftates it to be = 4,988. A. a. A piece of the mineral after having been ignited te rednefs, loft 2. per cent. Its reddifh colour had been chengen tobrown. Its figure had fuffered no alteration. 3 b. One hundred grains of the finely levigated mineral ig- nited for half an hour, loft five grains. Its colour was | changed to a dark brown. B. a. One hundred grains of ochroit, after being mixt with 200 grains of carbonate of potath, were ftrongly ignited, the mafs which could not be rendered fluid, was reddifh, grey and brittle. On being diffufed through water, as ufual, the ~ obtained folution was colourlefs. It remained perfe@tly tranf= parent; a proof that it did not contain tungften oxide; nitrate — of filver, mercury, lead, barytes, &c. proved the Kon of — acids, io b. The infoluble refidue of the laft procefs was boiled in nitro-muriatic acid, the filiceous earth being feparated, the | folution was decompofed by potath, and the whole boiled for | fome time. The alkaline fluid after being neutralized with | muriatic acid, and then mingled with carbonate of potath, fuffered no change. 8 a. 200 grains of the finely pulverized mineral, were firft q boiled in two ounces of muriatic acid, to which half an ounce © of nitric acid was gradually added, and the digeftion continued | for fome time. The whole became thus diffolved except the 7) filex contained in the mineral. Its quantity amounted to | 68 grains. a ni To the folution obtained in the laf procefs, carbonate of ammonia was added fo-long, till no permanent precipitate | | was produced, On letting fall into it fuccinate of ammonia, | a curdly precipitate fell, which vanifhed again on agitation, leaving ‘EXAMINATION OF THE OCHROITES, 209 leaving merely a pale red precipitate of fuccinate of iron, This being colleéted, wathed, dried, and ftrongly ignited, yielded nine grains of oxide of iron. c. The fluid thus freed from iron, and now colourlefs, was _decompofed by carbonate of ammonia. The precipitate obtained was white, and weighed 168 grains, on being deprived of water and carbonic acid by heat, ils white colour changed to cinnamon-brown. It weighed 109 grains. d. All the water employed for wathing the different pre- “cipitates were mingled, evaporated to drynefs, and the am- moniacal falt volatilized ; a minute quantity of a muriate was obtained, the bafis of which could not be determined. From what follows it will become evident, that the cinnamon- Peculiar earthj brown precipitate (c.) which forms the principal part of the foffil is a peculiar earth, diftinét from all the others hitherto known. The charaéteriftic property which it poffeffes of ac- | quiring a light-brown colour after being heated, has induced me tocall it ochroit earth*, which may alfo ferve for the mineral itfelf. According to this analyfis, 100 parts of the ochroite of Ridderhytta contain, . Ochroit earth - - = 54,50 Silex - = - 2 - 34 Oxide of iron - ee ye de Water, &c. (A.b.) - ° ° 5 Lofs - = = - é 5. iD 100. Charaéeriftic Properties of Ochroit Earth. 1. Ochroit earth is capable of combining with carbonic Ochroit earthy acid during its precipitation from acids by carbonated alcalies, cornice and ftrongly confolidating a portion of water, acid. 100 grains of the earth precipitated by carbonate of am- monia, and ftrongly dried, loft on being neutralized by nitric acid, 23 grains: 100 grains of the fame earth loft after being ftrongly ignited, 35 grains, 100 parts of carbonate ochroile therefore confifts of . Ochroit earth - - - = SOR (2 Carbonic acid Stas by Sem a Water - - sy 2 a 12 100. * From the Greek word wxeos, (Havefcens,) brownish yellow. Ver. VIIL.—Jury, 1804. Fy 2. Ochroit ~ $ é EXAMINATION OF THE OCHROITES. a.Itis brown. 9, Ochroit earth, after being freed from carbonic acid and’ water, by heat, always appears in the form of a cinnamon- brown powder. The intenfity of the colour is in proportion. to the heat applied. This colour is not owing to the prefence of iron, or inanganefe, &c. but it is a charaéteriftic property — of the earth, 3. Not reduci« 3. Ochroit earth included in a charcoal crucible, and ex-. _ bles pofed to the heat of the porcelain furnace, fuffered no change whatever. 4. Not fufibleas 4. Urged by the blow-pipe, it becomes phofphorefcent ; a - microcofmic fafed with pho{phate of foda and ammonia, it becomes tinged t nor borax. ; : Lipli : 5. by it, without effecting a folution of the earth, The falt ace. — ‘ quires merely a marbled lemon yellow colour. Borax has likewife no chemical effect upon it. This falt only effedis a mechanical divifion.. The earth always appears diffufed through the borax in minute floceulz, 4 g. Gives anun- 5. Ochroit earth mixed in different proportions with proper even brown as fluxes, and applied for painting of porcelain, proved unfuce porcelain colour. : : cefstul. The painted articles were light brown, but the co- lour was not uniform; a proof that no combination had been effected. 6. Difficultly 6. Ochroit earth combined with carbonic acid is eafily folu- foluble in acid ifble with effervefcence in acids. The tafte of the folution is the earth be Recs pure; but eafily Very rough and aftringent. The-concentrated folutjon is of an if carbonated. amethyft red colour; diluted with water, it becomes colour- lefs. Ignited ochroit earth, on the contrary,- is difficultly folu- Nitric acid. ble in acids in the cold; if nitric acid be employed, the folu« as is yellowifh red. 7. Sulphate of . The combination of ochroit earth with fulphuric acid, ochroit is cryf- jg cryftallizable. The figure of the cryftals formed | tallizable, and gai Seis : z pale'amethya the mafs of the fluids is the otahedron. They are se colour. of a pale amethyft colour, and difficultly foluble in water; but the fulphate of cchroit with excefs of acid, is more foluble ; ihe figure of the cryftals formed on the fides of the veffel, are a needle-fhaped, radiating from a centre, ‘They are more fo- lable than the former. q Sulphate of foda 8+ If a, folution of fulphate of foda be mingled with a folu- ~ decompofes mur. {ion of muriate or wnitrate of ochroit, a mutual decompofition or nitrate of L } « A i} ( | bl fi d, hiaitene. takes place. A white infoluble precipitate is formed, confift- Theinfoluble ing of fulp! iuric acid united to the ochroit earth, This com-— _ fulphate-of . bination echroites, - EXAMINATION OF THE OCHROITES. 911 bination may be decompofed by boiling it with double its weight may be deca of carbonate of foda. By this means ochroit earth may be P°!d by boiling ag with carb. of obtained very pure. foda ; and the’ 9. Ochroit earth is likewife foluble in fulphureous acid, the ¢2*th obtained . é 5 . Uuree folution cryftallizes in needles of a pale amethyft colour. Be aden 10. Muriatic acid diffolves ochroit earth, and yields ery- acid diffolves fials, the figure of which is the prifm. It is foluble in alcohol eens without imparting to its flame any particular colour. , Muriatic acid 12. Acetite of ochroit could not be cryftallized, but yielded abe ame iee it and cry ftallizese an adhefive mafs. "The alcohol fo- -13. Nitrate and muriate of ochroit is decompofable by ‘car- !tion does not colour flame. bonated’ earths and alcalies, the precipitate is milk-white. Aécetite of Alcalies and earths freed from carbonic acid, occafion a_yel- rai cryf- alilZaDlee lowifh grey precipitate. ~The nitrate and 14, Pruffiate of potath precipitates ochroit from allits neu- muriate precipi- _ 2 i ida ‘ 3 bl] tral folutions, milk white. The precipitate is foluble in mu- pea ae , ¥ cs -Fiatic and nitric acid.* : and by pruffiate 15. Tinéture of galls occafions no change in the folutions of oo 3 this earth. Not by galls, 16. Hidroguretted-hidrofulphuret of ammonia precipitates but by hidrog, the folution of ochroit earth, yellowifh white. see oes of 17. Water impregnated with fulphuretted hidrogen occa- Not by lds fions no change in the folutions of ochroit earth. fulph. watery 18. Succinales precipitate ochroit earth white. but by fucci- 19. Phofphate of foda, occafions in the folutions of this Phofphate of earth a white precipitate, which again vanifhes by the addition foda precipitates, of nitric or muriatic acid. al 20. Tartrites of potafh alfo precipitate this earth white. Tartrites preci 21. Oxalates effeét a like decompofition, the oxalate ee aay - ochroit, however, is not foluble in nitric or muriatic acids. 22. Alcalies and alcaline carbonates do not a€t on ochroit Alcalies do not earth. ' act on the earthe 23. Ammonia feebly aéts on it, under certain circumftances, Ammonia ‘as may be evinced from the following experiment : se A folution of nitrate of ochroit, prepared by diffolving 100 gtains of carbonate of ochroit (not abfolutely free from iron, ) in nitric acid, was decompofed by carbonate of ammonia, and digefted in the fluid, containing a confiderable quantity of carbonate of ammonia in excefs, for fome days, The fluid : _ * Tf the earth contained the muriates and quality of iron, it be- comes by this means manifefted. ; i P2 which - > EXAMINATION OF THE OCHROITES. S — iS which had acquired a yellow colour, was feparated and neu- tralized by fulphuric acid, and then placed ina warm place. A grey precipitate was thus obtained, which on being dried, weighed 1} grains, This precipitate, after being diffolved in nitric acid, yielded a blue precipitate by pruffiate of potath, this being feparated, a white flocculent precipitate fell down by dropping into the remaining fluid carbonate of potafh. This method is therefore applicable for feparating a minute quantity of iron, that may be contained in the fluid. General remarks From what has been ftated, it becomes obvious, that the and charaéters gchroit earth bears the neareft relation to yttria, for like this of the Ochroit . : : y earth. it forms a conneéting link between the earths and the metallic oxides. Like yttria it has the-property of forming a reddifh | coloured falt with fulpkuric acid, and is precipitable by pruffi- ate of potafh, but it differs from yttria, that it does not form {weet falts, that it is not (at leaft very fparingly) foluble in carbonate of ammonia, and that when ignited it acquired a cinnamon brown colour. It farther differs from yttria by not eing foluble in borax or phofphate of foda when urged upon charcoal before the blow-pipe, which falts eafily effe@ a folu- tion of yttria, and melt with it alfo into a pellucid pearl, XVI. Letter from Van Marnvum to J. C. Delamétherie, on Ritter’s Gal- vanic Experiments .* Ma. ORSTED of Copenhagen, on his way through Har-. lem, having fhewn me, by means of the apparatusin Teyler’s — New experiment Mufeum, fome difcoveries of his friend Ritter of Jena; I in proof of the made at the fame time a new experiment with him, which af identity of elec- , : : : : : tricity and gal- fords a freth proof of the identity of the fluid fet in motion by vanifme Volta’s pile and the common ele@trical machine, and an ac- count of which I imagine will be acceptable for your Journal. Two wires of Mr. Orfted having fhown me, that two wires of platina, latina, kept . : : ; 3 Ste a after having been kept five minutes in the chain of communica- chain of com- tion between the twoextremities of a galvanic pile, acquired munication be- } ae ah tlt * Fourn. de Phyfique, December, 1803, Vol. LVII. p. 471. convulfed the t_ See Ritter’s experiments, as communicated by Dr, Orfted, in legs of a frog, this prefent and fome other numbers of the Journal, thereby ON GALVANISM. 213 thereby the faculty of throwing the legs and thighs of a frog into convulfive movements, according to the difcovery of Mr. Ritter; I propofed to him, to pafs the ftream of fluid from a powerful eleétrical machine through thefe fame wires of plati- ha, in order to obferve, whether it would have the fame effeét on them as the fteam from the galvanic pile. We employed 2°4 expofed to : : : : the ftream of a the plate machine of 35 inches diameter, and of the new con- plate machine ftruétion, defcribed in the Journal de Phyfique tor June, 1791, for a like time : 5 : did the fame, vol. 38, (or Philofophical Journal, quarto feties, No. 2.)* put more Having paffed the ftream from it through the wires of platina, weakly. held a quarter of an inch from the conduétor, for the fpace of five minutes, we touched with them the crural nerves of a frog prepared in the ufual manner, and obferved immediately the fame convulfive movements in its legs and thighs, though not fo ftrong as in the preceding experiment. This lefs power- ful effeét of the ftream from the machine perfectly anfwered my expectations, fince my experiments in November, 1801, de- {ecribed in my letter to Mr. Volta, fhewed me that the ftream from the machine had not more than five fixths of the velocity or ftrength of the ftream fet in motion by a fimilar pile. We then repeated the experiment, keeping the wires of The experiment ates : . : was repeated platina in contaé with the conduétor of the machine, while we the wines hak paffed the ftream through them. Then holding the wires one been kept in in each hand, as in the preceding experiment, and in conta@ a a e with the two crural nerves, but keeping their oppofite extre- when the fenfi- mities feparate, their effeét on the fame frog, the fenfibility of ine ae fag ‘which was greatly weakened, was {carcely perceptible : but weakened, the on bringing the upper extremities of the wires together, while Shc ae . ‘the lower remained in contaét with the crural nerves, we no- tibe, dies ticed very ftriking convulfions in the legs of the frog, every onieh ie eae time the extremities were made to touch. A little fealing the wires were ‘wax, which had been ufed to keep the wires of platina infu- bro ny into Jated when held to the conduétor, and which ftill adhered to he i one of the upper ends, rendered the experiment ftill more fealing wax pre- are j : , vented the abfo= evident; for when we brought thefe ends together in fuch Bee ae manner, that a little of the wax prevented them from being the wires, no in perfec contaét, the legs of the frogs exhibited none of the a. took J * It'is a machine, that produces pofitive and negative electricity, like the pile of Volta. Delamétherie. : ' ‘ convulfive 214 EXPERIMENTS ON LIGHT. convulfive movements, that took place, notwithftanding every time the wires were made to touch each other completely. Thus we have a frefh proof of the identity of the fluid fet in motion.by the pile of Volta, and by a common eleGrical machine, ‘ XV. Experiments on Light; by Mr. Rrvver, ef Jena. Communicated by Dr, ORs PRD .+ Herfchel’s dif- "Vue: important difcovery of invifible folar rays, with which covery of invi- Hferfchel has enriched natural philofophy, has given occafic fible folar rays Pp pays g om. has given rife to tO another little know n, even in the country where it has been another.: made. Our knowledge | Our knowledge of light had made no perceptible advance- of light ata ftand ment fince Newton, ten Herfchel found, that all the phe- fince Newton ; nomena occurring during tMe decompofition of light by means of the prifm had not yet been noticed. Philofophers had con- tented themfelves with perceiving different colours, without examining by other proceffes, whether phenomena impercep- till Herfchel _ tible to the eyes did not take place. Herfchel, by means of © ae uae "the thermometer, difcovered invifible rays exterior to the folar yond the fee. fpeGirum, that poffefs the property of raifing the mercury. See eae the Mr, Rifter repeated his experiments with fuccefs; but con- Ritter, repeating fidering, that the different rays of light produce very different the experiment, chemical changes in bodies fufceptible of them, he conceived, pe ee aor that‘light ikewile contained invifible rays, which aéted che- invifible rays mically. He expofed muriate of filver to the a@ion of the ting chemical yeti farrier folar {peétrum, and found his conje@ure fubftantiated: the — found, that muriate of filver very foon became black beyond the violet peer ss edge of the fpeétrum; blackened a little lefs in the violet it: Geer att grew felf; and this action was ftill lefs in the blue, diminifhing thus blackeft beyond ore and more in proportion to the diftance from the violet, its violet edge, and the effeé di- till it became null. On expofing muriale of filver a little minifhed in pro- blackened, that is to fay, a little difoxigenated, to the fame i ig adtion of light, ils white'colour was partly reftored by the sa this, Tay, and fill more by the iawiGble ray bargeg Th. and the muriate little difoxige- steed hak reg * Yournal de Phyfique, December, 1803, Vol. LVII. p. 409. colour partly re- , : Tae ; frored by the in- The ’ 14 Violet be thrown on the phofphorus in a ftate of oxigenation, it EXPERIMENTS ON LIGHT. OVS ~The folar fpe€trum therefore is accompanied by two invifi- vifible ray be- ; *s , Rie: . youd the rede ble rays, one on the red fide, which favours oxigenation, and "Phus there is aa the other on the violet fide, which favours difoxigenation. invifible ray’ _ The vifible and coloured rays partake more or lefs of the pro- Promoting: oxi- : ; SO es: if genation, and perties of thefe invifible principles, whence we ought to infer, another the con- that all the coloured rays contain more or lefs of thefe princi- tty, ples a and the vifible and coloured Thefe experiments fucaeed very well with phofphorus. On "ys ages : ae c ; A aac * ni he « ) a letting the invifible ray adjoining the red fall on it, it immedi- che; weaintes of ately emits white fumes: but if the invifible ray adjoining the both. The invifible ray ae : : , okie onthe red fide is inftantly extinguifhed, with the fame rapidity as a frog is likewife kindles Par cnt lesan ; * phofphorus 5 convulled in gal anic experiments. de ce Thefe experimenis readily accord with fome others made by violet fide ex- the fame gentleman. He kept one of his eyes for fome mi- tinguifhes it ins P f ‘ d antly. nutes in contaét with the negative condu€tor of Volta’s pile, One . the eyes and after this operation all objets appeared red to him: but Beha Fe fome _) 3 . . . . m 7 after having kept it incontaét with the pofifive conductor, he aan ee faw every thing blue. It is to be obferved here, that the re- negatnReanseee tina and optic nerve, when the external part of the eye is a all objects brought into the negative ftate, become pofitive, and vice verfa; appeared red to becaufe the eye is filled with a fluid, in which the fame dif- Rae tiaer 2 tribution of eleétricity muft take place, as in water and other blue. fluids. It isin the pofitive ftate therefore, that the optic nerve Tachseote perceives all objeéts of ared colour; and in the negative ftate nerve is shh they appear violet. The chemical alion of pofitive eleétri- pofitive ftate 5 er. ihe f | PA at Sly iad os ea in the latter, city ikewife is the fame as that of red light; thatis, t oy) OlD negative. favaur oxigenation, Negative electricity and the violet ray The chemical ‘ i . i ‘ Ait r pofie poffefs the fame analogy, both promoting difoxigenation : as aaa dk the experiments with the galvanic pile have fufhciently fhown. likewife favours If I might be allowed to add any obfervation to thefe im- ioe ing ' ope - s ? portant difcoveries, I would mention one of the moft com- negative, the : Sat contrarys monly known facts 5 that the oppofite eleétricities, when Papel ia united, produce light; which feems to. demonftrate fyntheti- tricities too pros cally, what the preceding experiments have fhewn by analyfis. a light by We i } . : . ~) their union 5 This account was read to the philomathic fociety feveral vic feems to months ago, fince which time Mr. Ritter has publifhed fome prove fyntheti- os alte : ir iden- new obfervations that deferve notice. He has found, with all Sayan the prifms he ufed, that the folar rays give two coloured {pec- chemical rays. .- > ses a : Mr. R. has fince trums, which fpread in proportion to their diftance from the erate prifm, fo that at a certain diftance one nearly covers the other. the prifm affords * ie Sea aus The two fpectrums, 216 EXPERIMENTS ON LIGHT. diftiné ata | The experiment muft be made at a very fmall diftance from Pa EC the prifm, that of four inches for example, to diftinguifh the confounded to- two {peétrums, which become confounded together in propor- gether when tion to their diftance from the prifm. No doubt this is the farther off. : : ima : reafon why the phenomenon has fo long efcaped the notice of And the chemi- philofophers. This obfervation was accompanied by another, cal scale ge be (till more important; namely, that the chemical rays may be compiete c= . = F i med Svat completely feparated from the coloured rays. If the invifible folpare with- rays of the violet fide be made to fall on the red part of the fo- Sil eee fpeétrum, the procefs of oxidation may be completely fuf- pended there, and even difoxidation produced, without de- ftroying the red colour; and by means of feveral prifms we may even feparate all the coloured rays from the chemical So that we may rays. We may thus produce a coloured fpeétrum devoid of produce aco Chemical aétion; and a feries of chemical rays, analogous to loured fpeé&trum = 8 ¢ 5 devoid of chemi- the fpectrum, without any mixture of coloured rays. éalaction. We have not yet any accurate experiments, to determine The calorific : ? ee : rays ere Rot whether the calorific rays be likewife {eparable from the others, cae ae to particularly from the chemical rays: but the comparifon of dif- e g 2 Pe = . eae ie. ferent experiments made in winter and fummer, when the de- mical; butit grees of heat are different, though no difference in the force of they ce the chemical rays at different feafons has been obferved, lead ) 5 . the former differ to a belief that the calorific rays are feparable from the chemi- in degree in eal winter and fum- ~*"* f abr mer, the fatter It may be afked, why the different rays found in light fre- d te : That they ac. quently accompany each other, though they can fubfift fepa- company each ‘ately: and this queftion no doubt may be anfwered, when other, though we are able to fay, why the different fun@tions of eleétricity feparable, n : i eniberanmaally accompany each other, though they likewife are feparable. than attends a electricity. XVIII. On Spontaneous Inflammations. By G. C. BartHoxp1, Pro- Segor of Phyfic and Chemiftry.* Definition of SPONTANEOUS inflammation is that which 1s manifefted fpontaneous in. acombuftible body, without the immediate contaé of any inflammation. ignited matter, * From the Annales de Chimie, Vol. XLVIII. p- 249, or No. 1445 ; Thefe ON SPONTANEOUS INFLAMMATIONS« Thefe kinds of combuftion may be occafioned by different Caufes. caufes, the principal of which are: 1. Confiderable fri€tion. 2. The aétion of the fun. 3. The difengagement of caloric, produced in bodies, which, though not combuttible, by being brought near to other com- buftible bodies, may communicate fuch a degree of heat to them, that they inflame by the contaét of the air. 4. The fermentation of animal and vegetable fubftances heaped up in a large mafs, which are neither entirely dry, nor too wet, fuch as hay, dung, &c. 5. The accumulation of wool, cotton, and other animal and vegetable fubftances, covered with oily matter, particularly drying oil. 6. The preparation of linfeed oil for printers’ ink, of var- } nifhes, and in general of all fat. 7. The torrefaétion of different vegetable fubftances. 8. The fulphurated and phofphorated hidrogen gafes which are difengaged in many of the operations of nature, and of which, the latter generally inflames by the fole contaét of at- mofpheric air, even at a low temperature, and which is often feen at the furface of the earth like a fmall flame, known by the name of Jack o’Lantern, in places in which there are animal fubftances ina ftate of putrefaction: if other combuftibles are met with where the difengagement takes place, they readily catch fire. _ 9. The phofphuret of lime and potafh, which may be formed in the preparation of charcoal, particularly in that from turf, and from fome forts of wood which grow in marfhy fituations. _ This charcoal by being wetted, or by fimply attra@ting the hu- midity of the air, forms phofphureted hidrogen gas, which, by the contaét of the atmofpheric air inflames, and may fet fire to the whole mafs of charcoal. 10. The phofphorus which is fometimes, though rarely, _ formed in the carbonifation of different forts of wood, without combining either with lime or with potath in the ftate of phof- phuret. Thefe charcoals do not inflame fpontaneoufly at the common temperature of the atmofphere, but they produce a detonation by percuffion with nitrate of potath, or with fome other nitrates and metallic oxides to which the oxigen adheres but feebly, and which, being in the.ftate of thermoxide, retain much latent caloric. 5 _ | FriGion. 217 Pat Frictione Experiments with a tablet between two cylinders, ON SPONTANEOUS INFLAMMATIONS, 1. Friction. It is generally known that by rubbing two bodies sesh each other, they are heated; the intenfity of the produced heat depends on feveral circumftances, and chiefly varies in proportion to the hardnefs of the friétion, to the nature, and to the furface of the rubbing bodies: if the fri€tion takes place between combuftible bodies, fuch as the woods, the heat - which it excites is frequently fufficient to inflame them: if the bodies are not combutftible, fuch as ftones, or but little com- buftible, like the metals, they do not themfelves inflame, but they can communicate fuch a degree of heat to other combuf- tibles which furround them, that thefe can inflamé by the con- taét of atmofpheric air. ; Dr. Palcani having repeated the inane which have been long known for obtaining fire by the friétion of two pieces of wood, to one of which he gave the form of a tablet, and to the other that of a fpindle or a cylinder, he has allowed me to give the refults of fome of his experiments here, to fhew that more attention fhould be paid to the choice of the woods which are deftined to rub againft each other, in the conftruc- tion of machines and inftruments. Two cylinders of Tablet. Duration. ~ = Effect. Box-wood szint Box-wood ity" 5 Minutes Senfible heat Idem Poplar Idem Idem Idem Oak Idem Idem Idem Mulberry 3 Minutes Cons, heat and fmoke Idem Laurel Idem Idem Laurel Poplar 2 Minutes /dem Idem Ivy Idem _ Idem Ivy Box-wood . 3 Minutes Jdem Idem. Hazle Idem Idem _ Olive _ Olive Idem Idem Mulberry Laurel 2 Minutes Con. he. fm. & black Ath Oak _ 5 Minutes Senfible heat He Idem Fir Idem Idem . Pear-tree , Oak Idem Idem Cherry-tree ~ Elm Idem Idem Plum-tree Apple-tree Jdem Idem Oak Fir Idem Idem ON SPONTANEOUS INFLAMMATIONS. 219. On changing the experiment, and rubbing a cylinder of and with a cy- one of thefe woods between two tablets of the other, for ex- SON ic ample, a cylinder of poplar between two tablets of mulberry, the augmentation of the rubbed furfaces which are in contact with the air, produced a much more confiderable heat, and nearly all the woods mentioned above took fire. The effeét of the friGion alfo varies according as the woods The di dire€tion of employed, particularly if they are of the fame fpecies, are fae rubbed in the direétion of the grain of the wood, or when the fri€tion. grains of the woods crofs éach other. In the firft cafe the friction and the heat are much more confiderable than in the fecond. In large machines, in which there is a great deal of friction, Preventives the heating is prevented by directing a continual current of seediegie io leh cold water on the tubbing furfaces: in common machines, tion by fri@tion, and in coaches, waggons, &c. it is diminifhed by covering the rubbing furfaces with fome oily matter. There have been many examples, during the great heat of fummer, of coaches, and other machines fubjefted toa rapid motion, having taken fire, becaufe the greafing them had been negle&ted. The greafe, by hardening on the rubbing furfaces, inftead of di- minifhing the friétion, increafes it; and as this covering is very combutftible, it renders {pontaneous inflammation ftill more ealy. It is alfo preferable, in many circumftances, to rub machines with foap, talc, plumbago, or other fubftances, which, without being oily, are very unCtuous to the touch. 2. Adtion of the Sun. ” By concentrating the folar rays with convex glaffes or con- A@ion of the cave mirrors, the ftrongeft heat is produced, all forts of fan combuftibles are fet on fire, and the moft refractory fubfiances are melted: it may happen that other bodies may be found in circumftances, in which, without our concurrence, they pro- duce the effeéts of glaffes and burning mirrors: although thefe effe@s are rather phyfical than chemical, it is neverthelefs effential to make them known, to guard againft their danger, There are examples of fires produced by large glafs bottles, filled with-water and expofed to the fun, in an apartment. ‘Whenever the form of the veffel is nearly fimilar to that of a ; lenticular . 220 Heat from ine combuttible bodies. New metal Iridium. TWO NEW METALS IN CRUDE PLATINA. Jenticular or fpherical glafs, the rays are refra€ted, and by uniting in a focus, produce a heat capable of fetting fire to the combuftible bodies within it. 3. The Heat excited in Bodies not combuftible. It is known that quick-lime plunged into water, or fimply moiftened, produces a confiderable heat. This method has even been employed with fuccefs for heating apartments, green-houfes, hot-beds, &c. at little expence. This property of quick-lime of difengaging much heat by the contaét of wa- ter, and that, not lefs dangerous, of diffolving or corroding animal fubftances immerfed in it, require the greateft precau- tions when a confiderable quantity of quick-lime is kept to- gether, To preferve it, it muft be proteéted from the contaét of the air and of every {pecies of humidity, and it muft be carefully kept at a diftance from all combuftible bodies, fuch as wood, hay, ftraw, &c. which might inflame fpontaneoufly, © if the lime contraéted the leaft humidity. The Journal de la Haute-Saéne gave an account, laft year, of the deftruétion of a barn, one of the wooden partitions of which took fire from . a heap of quick-lime, intended for the repairs of the farm, having been carelefsly laid againft it. In nature a great number of analogous phenomena occur, in which bodies, by changing their compofition, or by con- tra€ting new combinations, heat fo much, or difengage fuch a quantity of caloric, that other combuftibles which are near them may take fire. (To be continued.) XIX. Difcovery of two new Metals in crude Platina, By SMiruHson Tennant, Eg. F. RS. Ar the laft meeting of the Royal Society a paper of Mr. Tennant was read, on the analyfis of the black powder which remains afler diffolving platina, fhewing that it contains two new metals, Mr, Tennant’s firft experiments were made laft ; . fummer, TWO NEW METALS IN CRUDE PLATINA. 991 fummer, and had been communicated to Sir Jofeph Banks, after which an account of one of thefe metals appeared in France, by M. Defcotil *, and alfo by M. Vauquelin. The properties afcribed to it by the French chemifts are, 1. That it reddens the precipitates of platina made by fal ammoniac ; 2. That it diffolves in marine acid; 3. 'That it is precipitated by galls and pruffiate of potafh. The properties mentioned by Mr. Tennant are, that it diffolves in all the acids, but leaft in marine acid, with which it forms oétahedral cryftals. The folution with much oxigen is deep red, with a fmaller proportion green or deep blue. Jt is partially precipitated by the three alkalies when pure. All the metals, excepting gold and platina, pre- cipitate it. Galls and precipitate of potafh take away the colour of this folution, but without any precipitate, and afford an eafy teft of its prefence. The oxide therefore lofes its oxigen, by water alone. When combined with gold or filver, it can- not be feparated by the ufual procefs of rejining thefe metals. As the French chemifts have not given a name to the metal, Mr. Tennant inclines to call it Zridium, from the various colours of it in folution. The fecond new metal is obtained by heating the black pow- New meta) _ der with pure alkali ina filver crucible. The oxide of this metal 7" unites with the alkali, and may be expelled by an acid and ob- tained by diftillation, being very volatile. The oxide hasa very ftrong fmell, from which Mr. Tennant has called it Ofmiwm, It does not redden vegetable blues, but ftains the fkin ofa deep red or black. The oxide in folution with water has no colour, but by combining with akalli or lime becomes yellow. With galls it gives a very vivid blue colour. All the metals, ex- cepting gold and platina, precipitate this metal. If mercury is _ agitated with the aqueous folution of the oxide, an amalgum is formed, which, by heat, lofes the mercury, and leaves the ofmium pure as a black powder. * See our Journal, Vol. VIII. p. 118. SCIENTIFIC 299 SCIENTIFIC NEWS, &ce. SCIENTIFIC NEWS, AND ACCOUNT OF BOOKS. Figure of the Orbits of the news Planets. By Junome DE LALANDE. Figure of the Tue mean diftance of each of thefe planets from the fun is ream val see seer which anfwers to 227 million of geographical miles nearly. Piazzi or Ceres, difcovered Jan. 1, 1801. Revolution 4 years, 7 months, 10 days. Mean longitude, Jan, 1, 1804 - 10% 11° 59” Annual motion - - ae tae eG Aphelion - = - 10 26 44 Node - - - An cole 5) Equation of the orbit = - - Se Eccentricity - - - 0’, O79 Inclination - = - 10 37 Albers or Pallas, difcovered March 28, 1802. Revolution 4 years, 7 months, 1} days. Mean Longitude, Jan. 1, 1804 - 9% 29° 53/ Annual motion - - 2 18 dv. . Aphelion - . 2” eal Node =. - - 5 22 2 Equation of the orbit = - - 28 25 Eccentricity *) - 0,2463 Inclination - - - 34 39 re ECT , Philofophical Tranfudtions of the Royal Society of London, for a the Year 1804. Part I. 4t0, 182 Pages, with five Plates — and 26 Pages of Metereologicut Journal. . Philofophical THIS -Part contains—1. The Bakerian Le@ure, Experi< eee aoingakag ments and Calculations relative to Phyfical Optics; by Tho- ciety, . mas Young, M.D. F. R.S. 2. Continuation of an Account — of a peculiar Arrangement in the Arteries diftributed on the — Mulcles of flow moving Animals, &c.; in a Letter from | Mr. Anthony Carlifle to John Symmons, Efq. F. R. S 7 3. An 3 ACCOUNT OF NEW BOOKS; 993 S$. An Account of a curious Phenomenon obferved on the Philofophical Glaciers of Chamouny ; ; together with fome occafional Obfer- a yal So- vations concerning the Propagation of Heat in Fluids; by ciety. _ Benjamin Count Ruse ffed: V.P.R.S. Foreign Affociate of the National Inftitute of F rance, &c. &c. 4. Defeription of a triple Sulphuret of Lead, Antimony, and Copper, from Cornwall; with fome Obfervations upon the various Modes of Attraétion which influence the Formation of Mineral Sub ftances, and upon the different Kinds of Sulphuret of Copper 5 by the Count de Bournon, F. R.S. and L.S. 5. Analyfis of a triple Sulphuret of Lead, Antimony, and Copper, from _ Cornwall, by Charles Hatchett, Efq. F. R.S. 6. Obferva- tions on the Orifices found in certain poifonous Snakes, fitue ated between the Noftril and the Eye; by Patrick Ruffell, M.D. F.R.S.: with fome Remarks on the Stru@ure of _ thofe Orifices, and the Defcription of a Bag connected with _ the Eye met with in the fame Snakes; by Everard Home, Efq. F. R. S. 7. An Enquiry concerning the Nature of Heat, and the Mode of its Communication; by Benjamin Count Rumford, V. P. F. R. S. Foreign Affociate of the National Inftitute of France, &c. 8. Experiments and Ob- fervations on the Motion of the Sap in Trees; in a Letter from Thomas Andrew Knight, Efg. to the Right Hon. Sir Jofeph Banks, Bart. K. B. P. R.S. Appendix, Metereolo- gical Journal kept at the Apartments of the Royal Society, by _ Order of the Prefident and Council. Analytical Effays towards promoting the Chemical Knowledge of Mineral Subfiances. By Martin Henry Keaprortu, Profefor of Chemifiry, Ajegor to the Royal College of Phy- ficians, Member of the Royal Academy of Sciences at Berlin, and various other learned Societies. Vol. II. 8v0, 267 Pages. Tranflated from the German, Cadell and Davies. THIS work is tranflated by the fame learned chemift to Analytical whom the fcientific world is obliged for the former volume, #Mayss ’ Its valuable contents are as follow. 73. Examination of the Auriferous Ores from Tranfylvania. 74. Analyfis of the fulphated Oxyd of Manganefe from Tranfylvania. 75. Exa- mination of Tungftate of Lime (Scheeluim). 76. Gadolinite, 77, Examination of the Egyptian Natrum (Soda). 78. Stri- ated 294 Analytical Effays. ACCOUNT OF NEW BOOKS. ated Soda. 79. Analyfis of the native Muriate of Ammoniac. 80. Examination of Saffolin. 81. Examination of the Plumofe Alum from Freyenwalde.. 82. Capillary Salt (Halotrichium) from Idria, 83. Elaftic Bitumen, from Derbyfhire. 84. Ex- _ amination of Mellilito. 85. Umbra (Umber). 86. Examin-~ ation of the muriated Lead Ore. 87. Phofphated Lead Ores. 88. Sulphated Lead Ores, 89. Tabular, White Lead Ore, from Leadhills. 90. Examination of the native Reguline ‘Antimony, from Andreafberg. 91. Antimoniated Silver, from Andreafberg. 92. Fibrous red Antimonial Ore. 93. White Ore of Antimony. 94, Arfeniated Olive Copper Ore. 95. Muriated Copper Ore. 96. Phofphaied Copper Ore. 97. Kryolite. 98. Beryl. 99. Emerald. 100. Examination of Klingftone (Echodolite). 101. Bafalt (Figurate Trapp). 102. Pitch Stone. 103. Addition to the Analyfis of Pumice Stone (Effay 33). 104. Examination of the Jargon (Zircon) from Norway. 105. Examination of Madreporite. 106. Pharmacolite. 107. Scorza. 108. Examination of the Fi- bruous Sulphate of Barytes. 109, Tabular Spar (Safel-fpath), 110. Examination of Miemite. 111. Examination’ of the prifmatic, Magnefian Spar, from the Territory of Gotha. 112. \— Examination of the ftriated grey Ore of Manganefe. 113. Earthy, black Oxyd of Manganefe. 114, Examination of the Afphaltum from Albania. 115, Earthy brown Coal.” 116. The Hungarian Pearl Stone. EE: 7 *,* W.N. acquaints G. S, that the fuppofition of Du — Hamel, that what was called mild volatile alkali contains chalk, arofe from a want of knowledge of the carbonic acid . at the early period alluded to in his letter. The additional weight in the carbonate of ammonia arifes from carbonic acid, and there is no reafon to fufpeét any volatilization of the earth during its preparation. If any were prefent, it might be de- te€ted by fulphuric acid, or, in preference, by oxalic acid, — either of which wou!d carry down the lime, ‘ Lhulos. Journal. Val. VILPLIX p.2 24. ee, of be Obi of Ne a Y fone de Sas a : Olbers or Eallas p ; a ‘ Fig. 5. | 7 i Miilow SeRujsell Cot ‘oy ’ , - * ‘ My Pl wa yO ‘ : — . . n ia . al ~- 6s % ve L Fay si a Js . * . \ ) . he f — ‘ \ ‘ ‘ . ’ M, + Z \ ‘ ; + : . ‘ ’ R toast r j 4 ' y= s ‘ - é < a, , Philos. Journal Vol VILPLKp.2Y. ole Me ge iy Me VILLE fg ae oN. fi Oe a / We p “ne Ee aha SP iia Ss Dj Vv x z OS Sk Ne ee | 1 Ri oP Semen MB 6 a og "2 a] a ety he Mutlow Sc. tufell: Cot Journal. Vol. VM. PUXL p. 224. l i wed, ih , Chae for Layeng Mi Dawid i! MLE’ 5, SS SS Sas ll WS ul Mh B Scale of 10 feet. =| = w Sc liufodd (oe ,, Pag fe lacie ale whe Warati 1 guna a ine TRY per manne «i BOF pee Philos. Journal.Vol. VILFLXIp. 224. G TEE. br shethe: wrthowl wv Hy, hy Ml CMa fey, “ arg Co Stde View. | OTe INUCTANUONENEELALLANUUHMITETETUAT TOT Schufse Mutiow -_—-~ A JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, Se SA pr ee eae IRE ‘ AND : ee eB + A ReTS, : AUGUST, 1804," j ARTLCLUE I, 4 On the Pajies, coloured Glages, or Enamels, of the Ancients. # By M, Kiarrotu.* i SECTION FIRST. Wee invention of glafs, which, in various refpeéts is fo highly Hiftory of the f valuable a produétion of art, is among thofe ancient euCanetige ee of _ of which hiftory has tranfmitted us fome account. Pliny re- Pliny” 3 Ace lates itas follows: + Fama eft, adpulfa nave mercatorum nitri, counts _ cum fparfi per littus epulas pararent, nec effet cortinis attollendis _lapidum occafio, glebas nitri e nave fubdidige. Quibus accenfis, permixta arena litoris, tranflucentes novt Liquoris fluxife rivos ; et hanc fui orizginem vitrt.” If we fuppofe this account to be _ merely an unfupported tradition, ftill it contains in itfelf no ‘circumftance that might render it queftionable. It deferves _ tather the more credit, as it is hardly poffible to imagine this invention could have had any other origin than that of ac- ? cident. $ a e Read in the Royal Academy of Sciences at Berlin, O&tober 4, _ 1798.—Tranflated by N. N. who received a copy from the author. | + Lib. XXXVI. Cap. 65. Vor. VIIL—Avcust, 1804, Q Though 296 COLOURED GLASSES OF THE ANCIENTS+ Though Pauw and fome other antiquaries are more inclined to afcribe this difcovery to the Egyptians, who are faid to have Glafs-houfes at conftruted the firft glafs-houfe, in the remoteft ages, at Diof- om se polis, the ancient capital of Thebais; yet it likewife appears, ages, from the writings of the ancients, that this art muft have ar- rived at a confiderable degree of perfeétion, chiefly among the and among the Phenicians; as alfo, in general, this nation feems, in her flou- Phenicians. —_rifhing age, to have been almoft in the exclufive poffeffion of manufactures. Sidon, that colony of theirs fo flourifhing by commerce, arts, and manufaétures, was not lefs famous on ac- count of her glafs-houfes. Thefe, according to the teftimony — of Pliny, obtained for fome hundred years the chief ingredients of their glafs from the fea-fhore near the Phenician town Acco, afterwards called Ptolemais, and now St. John d’Acre, in the vicinity of the fmall river Belus, which there empties itfelf into the Mediterranean. ~ Thenitrumor The fubftance which the ancients employed for the purpofe nese. ee of vitrifying the fand, is comprehended by the early authors un+ foda 5 der the name of nitrums but it has long been generally agreed, that they did not mean by it our nitrate of potafh, but the mine- — fal alkali or foda; confequently their nitraria were not nitre- works, but, ftriétly fpeaking, refineries of foda. And from the defcriptions which Pliny and others have given of their nairum and its properties, it is rendered probable, that in thofe or rather it con- times all faline {ubftances, whether efflorefcing upon the foil or ire of any falt Jeft by dried lakes, if not belonging to the muriatic genus, were eft upon the ground (not | Confideredas natrum. Hence undoubtedly, among thofe falts muriatic); — often occurred real nitre as well as native fulphate of foda. This impure falt However, fuch confufion in their ufe in manufaéturing glafs pian detri- has not produced any real detriment; fince the longer time al to the ; : : ‘ . giafs. during which the ancients expofed their materials for glafs to the action of the fire, has been more than fufficient to decom- pofe thofe neutral falts, and to expel from them their acid con- _ ftituent parts. q The art of co- _ The art of colouring glafs feems to be of nearly the fame an- pk Sarah tiquity as the invention of making it ; asis evident not only from Fores wal, uity as feveral paflages in the ancient writers, but may alfo be proved by glafs fel actual documents, and, among others, by the varioufly coloured glafs-corals, with which feveral of the preferved Egyptian mum- mie’ are decorated. This art fuppofes the poffeffion of fome.che- mical knowledge of the metallic oxides, becaufe thefe are the © only ih COLOURED GLASSES OF THE ANCIENTS. a8 fam only fubftances capable of producing fuch an effeét. But it would be a problem of difficult folution to determine, what _ Were the means and procefies employed by the ancients for this purpofe, as they had no acquaintance with the mineral Though the ane cients were ig- acids, which, at prefent, are ufually employed in the prepa- norant of our ration of metallic oxides. It is neverthelefs certain, that the mineral acids, t of givi ious colours to glafs mult, at leaft in jo) aie 9° art of giving many various colours to glafs muft, at leaft in joureq paftes in Jater Limes among the Greeks and Romans, have reached an high perfeétion, eminent degree of perfection ; for they knew how to imitate, by their paftes of glafs, even thofe gems which have a deep colour, fo as to deceive the eye very confiderably. A proof of this, among others, is afforded by the following words of Pliny *, relating to the artificial imitation of the carbuncle, a gem then in the higheft eftimation: ‘ Adulterantur vitro fi mal- lime: fed cote deprehenduntur, ficut alia gemme@ faititia.” It was in the time of Auguftus that the Roman architeéts Roman mofuie began to make ufe of coloured glafs in their mofaic decora- ihe an tions, befides the feveral fpecies of marble and other coloured ftones, which, before, were ufually employed with that de- fign. Such an application of the glafs-paftes was reforted to in a villa built by the emperor Tiberius on the ifland of Capri, as is fhewn by fpecimens lately found among its ruins. I fube _jeéted fome of thefe in my poffeffion to chemical analyfis, chiefly for the purpofe of difcovering what metallic fubftances _ the ancients employed to tinge thofe varioufly coloured mafles of glafs. I. Antique Red Gla/s. The colour of this glafs-pafte is a lively copper-red. The Antique red mafs is perfeétly opake, and very bright at the place of recent 8!5 9pake- fra€ture. This is probably the very fame glafs, of which Pliny fays:* “* Fit ed totum rubens vitrum, atque non tranflucens, Hamatinon adpellatum.” (a) Two hundred grains of this red glafs were finely tritu- Analyfis, 200 rated, and, together with 400 grains of caufiic potash, ignited apa we for half an Roar: ; by which management the mixture foon en- 400 gr. potath 3 tered into a thin fufion. After cooling, the whole mafs was foftened with water, then fuperfaturated with murtatic acid ; foftened with and, after this mixture had been again infpiffated to a faline Wr fuperfa- turated with muriatic aeid 5 * Lib. XXXVII. Cap. 26. infpiffated 5 3 diffufed in muck Q2 mafs, hot water. » 228 “COLOURED GLASSES OF THE ANCIENTS. mafs, it was again diffufed in a large quantity of boiling water, to which a flight portion of muriatic acid had previoufly been Silex felldown. added. Siliceous earth feparated ; which, colle@ted, edulco- rated and ignited, weighed 142 grains. ; The remaining (b) The filtered folution poffeffed a green colour ; and when folution depofited concentrated by evaporation, it depofited needle-fhaped ery {- cryftals of mu- hy E - riate of Zead by tals. When oncontinuing the evaporation no more fuch ery{- evaporation. — tals would appear, the remaining fluid was diluted with {pirit of wine, and thrown upon the filter. The colleéted cryftals were wafhed with {pirit of wine and dried ina warm tempera ture, upon which they weighed 32% grains. They confifted of muriated lead, equivalent to 28 grains of gently ignited . oxide of lead. The liquid was (c) I then fuperfaturated with cauflic ammonia the folution iat er thus freed from its contents of lead.. It was now of a dark-blue monia, and alu- colour, and let fall a grey precipitate; which being feparated, Yoni gl fepa- the folution was again neutralized with muriatic acid, reduced The rem. fluid by evaporation, and upon this combined with oxalate of potash being fat. with as Jong as any turbidnefs enfued. The precipitate thence mur, acid, then cae ‘ Higel* j evap. and precip. formed was oxalate of lime, which after ftrong ignition yielded by oxalateof — three grains of pure calcareous earth, . . Ap gave e**_ ¢d) ‘The ingredient copper was now precipitated from the Copper was then folution, by immerfing into it a polifhed piece of iron. The itil by ”% reguline copper obtained by this procefs amounted to twelve grains, for which fifteen grains of oxided copper muft be put in the account. Purification of (e) The above grey precipitate (c) thrown down by the the precipitated Cauftic ammoniac, was mixed and digefted with liquid cau/tic jes em soda. When to the filtered folution, again fuperfaturated with muriatic acid, carbonate of foda was added, aluminous earth ; fell down, which after wafhing and ignition amounted to five grains. ! Infoluble part (f) The remaining part that was left undiffulved by the Was irorte cauftic lye, appeared of a black-brown tinge. This, after wafhing and expofure to red heat, weighed two grains, and was oxided iron. | ‘ Hence, according to this analyfis, the fum of the conftituent parts of the two hundred grains of the red antique glafs-pafte de- compofed, confifts of, . Silex 5 COLOURED GLASSES OF THE ANCIENTS. 999 Silex «= = \. (aj'™ = 142° grains. Compofition of Oxide of Lead - (b) pS 28 the red glafs. of Copper (da) - 15 of iron = f) . 2 5 3 Alumine - - fe) = Lime : : (c) - nen 195 Qn comparing the external chara@ters of this red glafs- pafte gh probably #9 Icoria from ‘with the Cupreous fcorize of a lively brown-red, fuch as i S agney seniip, fometimes obtained on melting copper ores, it is rendered highly probable, that the ancients did not compound the above pate direétly from its fimple conftituent parts, but inftead of them have perhaps employed copper fcoriz, On that fuppo- fition they had nothing more to do, than to feleé the beft co- loured pieces to fufe and caft them into plates. II. Antique Green Glafs-Pafte. The colour of this green pafte is a light verdigris. Its mafs, Antique green like that of the preceding, is opake, and of a {coriaceous fplen- glafs; opakes Analyfis as ig’ dent fracture. ; sae sig. For its chemical analyfis I employed two hundred grains, which, having been treated in exaétly the fame manner as the ‘foregoing, I found to confift of the following ingredients : Silex - - = 130 grains. Component parts Oxide of Coppers = . 20 —— of the green ine e ‘ PBrirepacs gnamels ——— Tron - a oe —_—— Lime a a - ES itt se : Alumine - - - 1 eee 196 grains. This green glafs-pafte, then, contains the fame conftituent pig, only in parts as the red, only in different proportions, Both receive proportion of | _ their colour from copper: But the reafon why this metal pro- P2**s from che greene duces in the one.a red, and in the other a green colour, de- pends on the different degrees of its oxidation or faturation with oxigen. It is one of he chemical properties of copper, that in the fiate of a fub- oxide, that is only half faturated with oxigen, 4 if 3 230° COLOURED GLASSES OF, THE ANCIENTS. it produces a copper-red enamel; while, on the contrary, when perfeétly oxided. or fully faturated with that acidifying principle, the enamel which it yields is green. Pliny men- tions feveral preparations of copper that were in ufe in his time; he only dwells too long on enumerating their pretended medicinal virtues. Of fuch artificial preparations of copper fome might have been ferviceable in making green glafs- paftes, in the cafe that, perhaps, the native osides of copper, . of which in particular the coppet-mines on the ifland of Cyprus could afford copious quantities, were not then employed for this purpofe. III. Antique Blue Glafs. - Whether the an- ~My ae objeét in chemically decompofing this glafs, was os bree. thé falation af 4be queftion: What was the colouring matter which the ancients employed in order to tinge their glafs blue? The ftriking fimilarity of the colour of the blue antique glafs to that of our modern, which, as is well known, is tinged by means of cobalt, has induced feveral learned men to conjec- ture, that even the ancients muft have been acquainted with this foffil, as well as with its properties of colouring glafs blue, This was, likewife, the opinion of Ferber, when in his Letters “The affirmative from Italy, page 114, he fays: “ Jn the villa Adriani near Ti- generally, voli, near Frefcati, and in feveral places, antique mufaic works ; have been found which exhibited fome cubes of a blue vitreous compofition, and ferve as a proof, that the ancients muft have known the ufe of cobalt and the preparation of fmalt.” ‘This opinion he repeats in various places. buterroneoufly This opinion being fupported by no chemical proof, refts iia ek folely on the fuppofition, that cobalt is the only fubftance which is capable of affording a blue enamel. However, it is _ certain the ancients knew the art of giving, by means of iron, a blue colour to glafs refembling that which we produce by cobalt. . ‘The contrary A chemical demonftration of this faét has been given by Goin Gmelin of Gottingen, in his Chemical Examination of a Blue Glafs from an antique Mofuic Fragment *, which was found in digging a garden at Miimpelgard, and is probably of Roman * Commentat, Gotting. Vol. II. ~ origin, COLOURED GLASSES OF THE ANCIENTS. Q31.- erigin. It is true that Gmelin could, in his examination, employ no more than the fmall quantity of a few grains; but the refults were fufficient to thew, that the colouring principle in his fpecimen originated not from cobalt but from iron. ' A like refult is afforded by the following decompofition of and by our aus the blue glafs from the ruins at Capri. see Its colour is a fapphire-blue verging towards that of fmalt. Antique blue It is tranfparent on the edges only. Its fraGture, as well as ~ dageiic ’ : perfectly opake. that of the preceding, comes nearer to the fcoriaceous and ! conchoidal than to the fplintery. Some of thefe blue glafs- Some plates are plates are particularly diftinguifhed by this circumftance, -that eerie 4 they are not coloured blue throughout the whole of their mafs, hig but only to about two-thirds of their thicknefs. Each of the firata is fo nicely diftinét from the other, as to give the appear- ance of two plates adhering at their broad furfaces ; ‘the one blue, the other colourlefs. (a) Two hundred grains of the above blue pafte were re- Fusion with duced to a fubtile powder, and fufed with 400 grains of cau/tic foday &c. gave foda, The obtained mafs, foftened with water, was faturatea”** to excefs, and evaporated to a moderate drynefs. When re- diffolved in boiling water, it depofited /liceous earth, which, after wafhing and ignition, amounted to 163 grains. (6) The fluid was then fuperfaturated with cawzc ammonia, Alumine @ the A brown precipitate thence enfued, which, upon edulcoration, Procefs with am- ‘I digefted with a folution of caujtic pota/h. The flight portion cieaeme taken up of it by this alkali was again, after faturating the lix- ivium with an excefs of muriatic acid, precipitated by means “of carbonated foda, and proved, upon edulcoration and red heat, to be aluminous earth, amounting to three grains. (c) What remained undiffolved by the cauftic potath, was oxiged tron, merely orided iron, weighing nineteen grains when ignited and wathed. a (d) The liquor that had been fuperfaturated with cauftic phe tiquid con- ammonia and poffeffed a blueith tinge, was by flow evapora- tained a little tion fo far reduced to a fmaller volume, that the greateft part OPP ee of the muriate of foda, which had been generated and con- ‘tained in it, could feparate in cryflals. The fluid feparated from thefe, in which the acid predominated, and which now hardly exhibited any perceivable greenifh colour, was in vain exa- mined 232 COLOURED GLASSES OF THE ANCIENTS. mined for cobalt *. It contained only a flight trace of copper and lime. The firft of thefe was made to appear, by com- bining the fluid with pruffiate of potash, and the brown-red precipitates thus obtained amounted to a little more than two grains, which are to be confidered equivalent to about one grain of oxided copper. (e) At laft, carbonated foda threw down about half a grain of calcareous earth. Component parts In confequence of this decompofition, thofe two hundred sap wr patte rains of the antique blue glafs-pafte, muft have contained the following earthy and metallic conftituent parts: _ Siler - - (a) - 163. grains, Oxide of Tron (c) - 192, —— Alumine - - (b) = 2 eee Oxide of Copper (d) - 1. —-—— Lime - - (e) ° 05 —— 186.5 Other experi- As Ihave fubjeéted the above blue glafs to feveral other re but thew- xPetiments, merely with an intention of difcovering the co- ed nocobalte baltic portion it might poflibly contain, yet without finding the leaft trace of it, there appears to be no doubt, that its Iron can affrd blue colour entirely depends on the ingredient iron, That a blue enamel iron, under fome circumftances, is capable of producing a as is feen in the : ; {melting works. blue enamel, is clearly fhewn by the beautifully blue coloured {corize of iron, which frequently are met with in the high furnaces on fmelting frliceous iron-ftones. But we are not fufficiently acquainted with the circumftances and conditions under which this colour is produced; for the affertion of Henckel, and fome other earlier authors, that by means of iron, cemented with arfenic, the fame blue tinge can be given glafs which it acquires from cobalt, has not yet been fufficiently * It is well known that nature tinges the /apphire, lapis-lazult, blue clays, &c. by means of iron without cobalt; but man is not poffeffed of her means. A chemical friend, with whom the tianf- Jator had a converfation on this fubjeét and on the difficulty of proving the accuracy of the above azalyfs by a fynthetical proce/s, Juggefted the idea, that fuch a blue pafte could, perhaps, be made without cobalt by the intermedium of Japis-lazuli ; an idea which: may afford a fubject for experiment.—Tran/fl, confirmed. | As 1) ae COLOURED GLASSES OF THE ANCIENTS. 233 confirmed. Whence, after the difcovery of the blue from ‘cobalt, the art of tingeing glafs blue by means of iron has had the fame fate with feveral other attainments now loft; namely, to have been difcarded and forgotten on the account of new invented, more commodious, and certain expedients and methods. SECOND SECTION. THESE coloured mufaic glafs-paftes of the ancients agrees The preceding with refpeé to their opacity and {coriaceous fra€ture, with st modern enamels. On the other hand, the deceitful imitations of gems already mentioned before fhew, that the ancients likewife knew how to prepare beautiful, high-colowred, and tranfparent glafs-paftes. But however well known thofe works in glafs of the an- but the ancients cients may be, fince both earlier and later writers have given eflel organs fufficient information of them, and feveral fpecimens pre- ing, little known ferved in the colle&tions of antiquaries afford a dire know- ‘© antiquaries ledge of this fubjeét; it is, on the contrary, very furprifing, that antiquaries are fo little acquainted with that entirely pe- culiar and by far more remarkable painting on glafs, which is _ formed of varioufly coloured delicate glafs fibres, joined with It is formed of the greateft nicety, and by fubfequent fufion conglutinated in- pr F ution to an homogeneous compaé& mafs. In the earlier works on fufion: antiquities this fcarce produétion of art is not at all mentioned ; the reafon of which is probably this, that the fpecimens now exifting of it were found, perhaps, only about the middle of this (laf) century. Among later antiquaries Count Caylus appears to be the Firt mentioned firft, who in his Colle&ions of Antiquities has given informa- ee tion, accompanied by rather inadequate drawings, of this fin- yore gular fpecies of mofaic work, Winkelmann has afterwards, in his Annotations on the Hiftory of the Art among the Ancients, (page 5, feq.), more accurately defcribed two other antiques of this kind; with the appellation, Pi@ures made of Glajs- Tubes, in the following paffage: ‘* The works of the ancients Ample defcrip- in glafs, which are not noticed in the Hzfory of the Arts, de- see ke paki ferve particularly to be mentioned in this place; more efpe- cially, becaufe the ancients carried the art of working in gla{s to a much higher degree than we have arrived at; a fa& which, to thofe mie have not feen their works of this kind, Rigi hea | might 934 COLOURED GLASSES OF THE ANCIENTS. might have the appearance of a groundlefs affertion.” After which he mentions a floor formed of green. glafs-plates difco- vered in the Farnefe-ifland, as well as fome fragments of glafs-cups, which muft have been turned on the lathe, and then proceeds as follows: ‘ But the art ftrongly claims our admiration in two {mall pieces of glafs, which laft year (1765) were brought to Rome. Each of them is not quite one inch Very curious Jong, and one-third of an inch broad.. One plate exhibits, on antique enamel : : Z of a duck ; a dark ground of variegated colours, a bird reprefenting a duck of various very lively colours, more fuitable to the Chi- nefe arbitrary tafte, than adapted to thew the true tints of na- ture. The outlines are well decided and fharp, the colours beautiful and pure, and have a very ftriking and brilliant effeé&t; becaufe the artift, according to the nature of the parts, has in fome employed an opake, and in others a tranfparent traced and fi- glafs, The moft delicate pencil of the miniature painter Hirt could not have traced more accurately and diftin@ly, either apd effect; — the circle of the pupil of the eye, or the apparently fcaly fea- thers on the breaft and wings, behind the beginning of which and continued this piece had been broken. But the admiration of the be- — ae cbse of holder is at the higheft pitch, when, by turning the glafs, he the piece, mi- fees the fame bird on the reverfe, without perceiving any dif- pany et oa ference in\the {malleft points; whence we could not but con- clude, that this piéture is continued through the whole thick- _) nefs of the fpecimen; and that, if the glafs were cut tranf- verfely, the fame picture of the duck would be found repeated in the feveral flabs ; a conclufion which was ftill farther con- firmed by the tranfparent places of fome beautiful colours upon the eye and breaft that were obferved. The painting has on both fides a granular appearance, and feems to have been formed, in the manner of mufaic works, of fingle pieces; but fo accurately united; that a powerful magnifying-glafs was unable to difeover any jun@ures. This circumftance, and the continuation of the picture throughout the whole fubftance, — rendered it extremely difficult to form any direét notion of the — ft is found to procefs or manner of performing fuch a work. And the con- | confift of threads Cention of it might have long continued enigmatical, were it of glafs feen ; ze 4 : endwife. not that, on the feétion of the fraéture mentioned, lines are obfervable, of the fame colours which appear on the upper — furface, that pervade the whole mafs from one fide to the 4 other ; whence it became a rational conclufion, that this kind q CGLOURED GLASSES OF THE ANCIENTS, 235° of painting muft have been executed ‘by joining varioufly cos loured filaments of glafs, and fubfequently fufing of the fame into one coherent body. The other fpecimen is of about the Another fpecie fame fize, and made in the fame manner, It exhibits orna- oes tai ad- mental drawings of green, white, and yellow colours, which are traced on a blue ground, and reprefent volutes, beads, and flowers, refting on pyramidally converging lines. All thefe are very diftin€t and feparate, but fo extremely {mall that even a keen eye finds it difficult to purfue the fubtle endings, thofe in particular in which the volutes terminate. Notwithftand- ing which, thefe ornaments pafs uninterruptedly through the whole thicknefs of the piece.” Of the fame glafs-pafte, which has been here defcribed, The fame were mention is made by Sulzer in his Theory of the Polite Arts, un- ten by Sulzer. der the: article Mufaic (mofaich). Having feen the piece itfelf in the houfe of its then poffeffor, Cafanova, at Drefden, he confirms, in the capacity of an eye-witnefs, the defcription given by Winkelmann, and calls it ‘* a remnant of antiquity, which indicates the exiftencé of an art brought to the higheft degree of perfeétion.” Mr. Townley, of London, enumerates, among the principal Extremely mi- rarities of his celebrated cabinet of antiquities, the ftone of a 7° bird in Wir, : : : i 4 wnley’s cole ring of a fimilar antique glafs-pafte, which reprefents a bird of le@ion. fo fmall a delineation, that it cannot be diftinétly feen but by _ means of a magnifying lens. As very few fpecimens of this fpecies of glafs-painting, Two fpecimens which undoubtedly muft. be reckoned among the loft attain- i7 pofleffion of ments of art, and of which even the exiftence is ftill fo little “"* ssi known, are met with; I think it not fuperfluous to give the following notice of two new famples which I poflefs of this clafs of antique fubje&ts. Both pieces have a heart-fhaped Defcription. form. The principal front is flat, the reverfe is convex, and has from eight to ten prominences (Ecken). The length of one of them is one inch, the breadth four-fifths, and the thick- nefs two-fifths of an inch. The other fpecimen is two-thirds fmaller. As to colouring and manner of drawing, they are both nearly alike. The principal mafs of the larger is of a dark-blue, and wholly opake; but that of the /maller isa fapphire-blue, and in fome places tranfparent. The blue ground is embellifhed with voluted, flellular, minute flowers, of fo very {mall 4 delineation as to. be hardly imitable by the 4 pencil 936 ON $PONTANEOUS INFLAMMATIONS, pencil of the miniature pamter. The colours of thefe flower= like ornaments, which are red, green, brown, fky-blue, and | white, are pure and lively. The delineations pervade the whole fubftance, and upon a broken part it is feen by mere infpeétion, that thefe delicate figures have been formed of parallel glaffy fibres of various colours, conglutinated by means of gentle fufion. Coloured plate As the drawings given by Count Caylus afford but a very of the larger Z 2 Fa y ; ute - {pecimen. imperfeét idea of that ingenious enamel-painting, I fubmit here a delineation of the larger of my two fpecimens. Fig. 1, Plate X11I. reprefents it in its true fize; Mg. 2 exhibits it magnified. Invention of —§ On this occafion the following paflage from a letter of Meyer to multi- v7 Kaftner *, concerning an invention of the ‘celebrated p'y copies of é paintings. Tobias Mayer, may well deferve a place here. ‘* Mayer poffeffed the art of making a number of perfeétly fimilar copies of a painting. He compounded his picture of coloured waz- crayons, im the fame manner as a prifm may be compofed of thinner prifms of oF Hane length. Every tranfverfe cutting afforded then acopy.” Meyer might probably have been led to this method of imitation in wax, from the infpeétion of a mufaic work of the kind here defcribed. II. On Spontaneous Inflammations: Ry G.C. BarTHOLpl, pte Jefor of Phyfic and Chemiftry. (Concluded from Page 220. ) 4. The Fermentation of Animal and Vegetable Subftances. Heat from fer- Tue greater part of animal and vegetable fubftances, when mentation. they ftill retain humidity, and are accumulated into large maffes, enter into fermentation, a change in their compofition is effe€ted, and they frequently heat to the point of inflamma- tion. It is thus that magazines of hay, of turf, of flax, of hemp, flacks of hay or ftraw, heaps of linen-rags in paper- mills, &c. take fire fpontaneoufly. * Alsrasine Geographifche Ephemeriden, by Zach, 1798. Pree a, Pe oe It t Se i> 9 deal ON SPONTANEOUS INFLAMMATIONS. 237 It is principally hay which requires precaution; if the hay- harveft happen in rainy weather, it is commonly ftacked be- fore it is thoroughly dry, and in this ftate is more difpofed to ferment and to heat. If a hay-ftack is obferved to be in fers mentation, great care muft be taken not to throw it down too fuddenly, the exterior layers muft be carefully detached one after the other. It almoft always happens, that when a hole is made in the middle of a ftack of heated hay, it takes fire fuddenly. N othing, however, is more eafy than to prevent thefe fatal Utility of adding accidents: when there is any reafon to fear that the hay which * ¢ hays is intended to be houfed or ftacked, is not fufticiently dry, it is only neceffary to fcatter a few handfulls of common falt (muriate of foda) between each layer. It would be very ill judged to regret this trifling expence; for the falt, by ab- forbing the humidity of the hay, not only prevents the fer- mentation and confequent inflammation of it, but it alfo adds a tafte to this forage which ftimulates the appetites of ~ ° cattle, affifts their Beeion and preferves them from: many difeafes. During the great heats of fummer, it frequently happens that heaps of dung inflame fpontaneoufly: great care fhould be taken to fprinkle them frequently with water in the fummer . feafon, and to keep them ata certain diftance from habitations, as well to prevent fires as with a view to falubrity. 5. The Accumulation of Animal and Vegetable Subjtances covered with an Ol, If animal and vegetable fubftances heaped into a large mafs, Heat from greafy can take fire from the heat produced by their decompofition, *%™4! and ve- 3 : ny getable matters, this accident is {till more to be dreaded when they are covered with oily matters, and particularly with a drying oil. Befides the accident which happened at the manufactory of Lagelbart, and of which our colleague Hauffman gave an account to the Society, and the fire which took place in one of the fineft manufa@tories at St. Marie-aux-Mines, there are many other examples of wool, ftuffs, and pieces of cluth, which were not freed from greafe, taking fire in the warehoufes when they were folded together, and even while moving them from one place to another when they were in large quan- tities; this is principally to be dreaded when linfeed oil, or ~~ any 938 ON SPONTANEOUS INFLAMMATIONS. ny other oil, drying in itfelf, or rendered fo by oxide of lead, is employed in the preparation of thefe ftuffs. In the manufaéture of cloths, only olive oil, or oil of 5p fhould be ufed to greafe the wool. It fometimes happens on boiling flowers and herbs in it which occurs in feveral pharmaceutical operations, that, after being taken out, the herbs dried in the oil inflame fponta- neoufly: care fhould therefore. be taken when thefe herbs are thrown i not to heap them near other combuftible bodies. _ There have baer feveral examples of veffels bcsieg been burnt in fea-ports, either by the fpontaneous combuftion of _ heaps of cordage coated with tar, or by a mixture of linfeed oil boiled with lamp-black, and inclofed in a bag. 6. The boiling of otly Matters. Fire from boiling In the preparation of fome varnifhes, fuch as printers’ ink, eily matters} in which Jinfeed-oil, boiled to a certain confiftence, is gene- rally made ufe of, it frequently happens that the oil takes fire, unlefs the neceffary precautions are employed: the fame effect takes place in melting butter, lard, or any other greafe, if they are heated too much ; fo that, in thefe operations, it is always neceflary to remove every other combuftible fubftance, to have a lid at hand to cover the veffel as foon as the fire has caught, and particularly to take care not to pour water upon it, which — inftead of extinguithing it, would fpread it more and give it — greater activity. 7. Torrefaétion. and from roafted There are many vegetable fubftances which increafe their — oc er fub- power of inflaming fpontaneoufly by torrefaétion, if they are — ‘ inclofed in facks of cloth, which leave them in conta@ with — the furrounding air; fuch are faw-duft, roafted coffee, the — meal of grain, and leguminous fruits, fuch as French beans, lentils, peafe, &c. There have been feveral inftances of ftables having taken — fire from a bag of roafted bran which had been applied to the — neck of a fick animal, and had inflamed fpontaneoufly. The — inhabitants of the country who, in fome diforders of theit — beafts, are obftinate in applying this remedy, to which others _ ON SPONTANEOUS INFRAMMATIONS, 239 ef more efficacy and lefs danger might be fubftituted, fhould at leaft be careful not to inclofe the bran in the cloth, either too hot or too much roafted. . Brewers, after having made their barley and other grain, which they employ in making beer, germinate, dry it in a kiln, except what is intended for pale beer, and they gene- rally roaft it more or lefs highly, to give the beer a deeper or paler colour. If, therefore, when the grain is brought from the kiln, it is put, ftill hot, into facks, it frequently hap- pens that it heats and takes fire, and this has eccafioned feve- — tal fires in breweries. 8. Sulphurated and phofphorated Hidrogen Gas, The nes of fubterraneous fires and volcanoes is generally Inflammation of: attributed to the decompofition of pyrites, or metallic ful. ha eee aa ie A ; phofphorated hie phurets, buried in the interior of the earth. Thefe pyritous drogen gas. mafles are decompofed by the contact and concurrence of water and air, and the decompofition is always accompanied by a gteat expanfion of caloric, and a difengagement of a very in- flammable gas, called fulphurated hidrogen gas. This gas in- flames at an elevated temperature, and can communicate the inflammation to the fulphur of the pyrites, to the coal and other bituminous matters which generally accompany it. Similar inflammations are fometimes obferved near coal-pits, Jn exploring the coal, veins and infulated maffes of pyrites are frequently met with: fince thefe pyrites always communicate a bad quality to the coal, the miners generally lay them afide, and throw them out of the pit: if thefe heaps of pyrites, mixed with coal, are then expofed to the alternate aétion of the fun and rain, they heat and inflame, Great care -muft therefore be taken that thefe accumulations of pyrites fhould be kept at a diftance from all combuftible bodies to which they would neceflarily communicate the inflammation. _ There are many operations of nature in which fulphurated hidrogen gas is formed, but it often enters into other combina. tions as it forms, it diffolves in water, or difengages at a tem- perature too low for it to inflame. By boiling phofphorus i in a folution of potafh or Sinai phof- phorated hidrogen gas is difengaged, which, being much more combuftible than fulphurated hidrogen gas, inflames at a low temperature as foon as it comes in contaét with atmofpheric air. This 240 ON SPONTANEOUS INFLAMMATIONS. This gas, which in chemical experiments offers the beautiful f{pedtacle of a fountain of fire over water, is produced natu- rally by the putrefa@tion of animal fubltances which are buried. The lights which are frequently feen to come out of the earth, and which are known by the name of Jack o’ Lanterns, are only owing to the difengagement of this phofphorated hidrogen gas: as thefe lights generally appear moving about in places where they do not touch dry combuftibles, they feldom occa- . fion difagseegble accidents; but they are alfo difengaged in forefts, and it may happen that in hot fummers, when the grafs and brufh-wood are thoroughly dry, the gas in combuftion may meet with thefe combuftible materials, and fet fire to them, and thus produce the conflagration of a whole foreft: we fhould not therefore, too lightly, and without fufficient proofs, attribute to the malevolence or to the connivance of mankind, thofe dreadful events which are ‘fometimes only the refult of : | caufes purely natural. , 9. Sulphuret and Phofphuret of Lime and of Potafh formed an the Combuftion of several Vegetables. Sulphuret and Sulphur is always formed when gypfum (fulphate of lime) or phofphuret of any other fulphate, whether earthy or alkaline, is ‘ftrongly diene or potas se ioe charcoal, wood, or, generally, with any com- buftible which is reduced to charcoal by heat. The fame falts form fulphureous waters if the remains of animal or vegetable fubftances are left in a water in which it is diffolved; fo that it frequently requires only a little fulphate of lime, or fome other fulphuric falt, to communicate the odour and tafte of fulphur to water which is ftagnant. Pyrophorus. Pyrophorus is obtained by calcining the alum of commerce,. or fulphate of potafh with fugar, meal, or any other fubftance which is reducible to charcoal. The inflammation of pyrophorus which takes fire by the fole contact of humid air, is only owing to the fulphuret of potafh, which by attracting the humidity of the air, heats to that point that it kindles the carbonaceous matter which fur- rounds it, and which being in a ftate of greater tenuity, is fo _ much the more difpofed to burn. A pyrophoric But fince many of our common combuttibles contain fulphu- se be ric falts, it may happen that, in their combuftion, a pyrophoric ‘ormed in ordi- . . F i hate | nary combuf- matter is fometimes formed by chance, which remains in the tion. refidue ON SPONTANEOUS INFLAMMATIONSs OA} tefidue of the combutftion, efpecially if the combuftible is not entirely confumed, anda part is not reduced into charcoal, which frequently happens in the fire-places in which the com- buftibles are not burned in grates, and the afhes are not fepa- rated from the charcoal. There have been inftances of houfes having been burnt by afhes intermingled with the charcoal which had been taken too early from the fire-place and put into places where they were furrounded with combutftibles, which they fet on fire by a fpontaneous inflammation. Hap= pily thefe-caufes of conflagration rarely occur; for pyrophorus does not retain its property of inflaming for any length of time, and it is frequently decompofed fhortly after its produ@tion, without occafioning any unpleafant event: neverthelefs, care fhould always be taken not to put afhes newly burned, and which are {till intermingled with charcoal, in places where they can communicate with combuftibles. The formation of a pyrophoric matter is principally obferved in the preparation of the foda of commerce, which is obtained by the incineration of different maritime plants containing much fulphate of foda, and which, in the combuftion, fome- times furnifh a certain quantity of fulphur, greater or lefs, ac« ‘cording to the manner in which the operation is directed. - - The formation of phofphuret of lime has great analogy with that of fulphuret of lime. Although the phofphoric acid is not found fo often in vegetables as the fulphuric acid, it neverthe- lefs exifts in them in greater quantity than has hitherto been Phofphoric acid believed: it is principally found in moft plants which grow in ae. a marfhy places, in turf, and in feveral fpecies of the white woods. In reducing thefe woods into charcoal, a fmall quan- tity of phofphorus is fometimes formed, which may remain combined with the fame bafes as retained the phofphoric acid before the combuftion: the phofphorus, by forming other comb.nations, may be rendered incapable of occafioning any accident, but it may alfo happen from a concurrence of feve- ral circumftances, that charcoal impregnated with any phof- phuret whatever, may, by expofure to the action of a warm and humid air, difengage phofphorated hidrogen gas, which, by the contaét of the atmofpheric air, will take fire and com- municate the inflammation to the mafs of the charcoal. Two examples of this kind of fpontaneous combuftion have Spontaneous ine taken place in the powder magazine of Effone, in the years 8 Senn pe he Ver. VIII,.—Aucust, 1804, R and powder magae Zine, YA ON SPONTANEOUS INFLAMMATIONS, and 10, The firft time the receiver of the machine for fifting the charcoal caught fire, and the fecond time it began in the magazine of charcoal, without a fufpicion of any other eaufe except that of a fpontaneous inflammation. The different re« ports made on thefe two events, have been inferted in the public journals; but the explanations that were given of them were not fatisfa@tory. It feems very probable that they were occafioned by fome phofphorus contained in the charcoal; and this explanation has the more weight, becaufe willow (bour- daine), which is ufed at Effone, as well as in moft other pow- der-manufaétories, and which, in many refpeéts, deferves the preference over other woods in the preparation of powder, contains phofphoric acid, at leaft that does which grows in our neighbourhood. Charcoal from turf begins to be employed in fome domeftic and other operations; but as it is much difpofed to fpontaneous inflammation, its ufe fhould be prevented, or at leaft it fhould be ftored with great precaution. It has happened at Paris and other places, that magazines of this charcoal, which were un- — fheltered, have taken fire by the combined aétion of the heat and rain. 10. Phofphorus fometimes contained in Charcoal. Betonation from Tt may alfo happen that the fmall quantity of phofphorus che posielnme which is fometimes formed in the carbonization of different forts of wood, without uniting either with the lime or the pot- afh, remains combined with the charcoal, which then does not difengage phofphorated hidrogen gas, nor does it readily in- lame by the fole aétion of water or of a humid airy but which, by percuffion with falt-petre (nitrate of potafh) may produce a powerful detonation. It is very probable that the three fuc- ceflive explofions which took place in the powder-mill at the manufactory of Vonges, were partly owing to a fimilar caufe. Charcoal pro- Charcoal has, in general, great influence on the different wee iad caufé produétions of nature and the arts. It is frequently obferved lity of told thort in forges and founderies, particularly in thofe of iron, that the iron. produéts vary according to the nature of the charcoal employed. ' The bad quality which is fometimes found in iron, of being brittle when cold, is generally attributed to the phofphoric acid contained in the ores: but fince the fame ore, by the fame pro< , - ceffes, ATTRACTION OF WATER BY AIR. ceffes; furnithes better iron in one foundery than in another; the difference feems eerily to arife in pact from the char coal. Such are the principal caufes of fpontaneous combuftions, whofe effeéis are fo much the more dangerous by being leaft expected. The Society of Emulation thought they fhould ren- der an important fervice to every clafs of proprietors, and par- ticularly to the inhabitants of the country, by developing the phyfical knowledge which might guard them againft dangers, of which they are too frequently the viGims, from ignorance and a fatal want of forefight. I traft I have fulfilled the wif of the Society, and of the firft Magiftrate, whofe intelligence and conftant folicitude extend, without exception, to every objeét which may contribute to the profperity of the country and the happinefs of the governed. Ill. On the Soliition of Water in the Atmofphere; and on the Nature of atmofpherical Air. By Mr. Joun Goucu. From the Author. . To Mr. NICHOLSON. SIR, I DO not recolleét.any philofopher or meteorologift, who has attempted to demonftraie the chemical union of atmofpherical aif and waier, by help of the following fa€ts and arguments. Should the prefent endeavour, to eftablith the propofition; ap- ' pear deferving of a place in your Journal, the infertion of if will oblige, Yours, 8c. JOHN GOUGH. Middlefhaw, July 16, 1804. 243 Exp. }. If a cylinder of dry porous wood be put into a ftrong Dry vegetables glafs tube, nearly of the fame diameter with itfelf, and water be poured into the veffel, the particles of the fluid will pene- trate the wood, and caufe it to fwell, fo as to burft the glafs. Some writers affirm, that the fame artifice has been ufed with fuccefs to fplit rocks, an operation which is commonly per- formed by the elaftic power of gun-powders A quantity of Rg motion attract waters 244 Aqueous va- ATTRACTION OF WATER BY AIR. motion is generated in this experiment, which cannot be re- ferred to the ation of gravity. We muft therefore afcribe it to another force, namely, the mutual attraction of wood and water in a liquid form. Exp. 2. If a piece of whip-cord or tharm be ftretched by pour attracted by the heavieft weight, itcan fupport, the pendent body will af- dry vegetables, &ca The force of affinity perma- nent. Hygrometrical attraction is diminifhed by the acceffion of water. cend, as oft as the ftring or gut contraéts, in confequence of an acceffion of water derived from the atmofphere; on the con- rary, it will defcend, when the cord begins to relax from the lofs of moifture. The motion generated in this inftance, proves atmofpherical vapour to be powerfully attraéted by the dry fibres of vegetables and animals; confequently thefe fubftances have a ftrong affinity to water, not only in a liquid form, but alfo when it is diffufed through the air. This affinity or force will be called the hygrometrical attraGtion in the fequel of the effay, for the fake of perfpicuity. The preceding experiments have not the leaft claim to no- velty; but they are the preliminaries of an inference, which is of moment in the prefent queftion. For affinity is a fixed re- lation of bodies, creating a difpofition to coalefce, in fuch as are thus mutually related, as often as water is combined with another fubftance. The union muft therefore be permanent, unlefs it happens to be diffolved by an external caufe. Now as any certain force only gives way to another fuperior and contrary to itfelf, it is evident that a moift body, which dif- charges a portion of the water it contains, is obliged to part with it by a more powerful attra€tion, exifting in its neigh- bourhood. It is to be remarked, that temperature is one of the external caufes alluded to above; but it is difregarded at prefent, becaufe the effets of its changes may be obviated in the following experiment, which is intended to throw addi- tional light upon the bygrometrical attraétion, Exp. 3. Take two bibulous fubftances, fuch as two flices of fponge, or a piece of {ponge and fhred of woollen cloth. Make the one wet and keep the other dry; then put them both into aclofe veffel of glafs or metal, placing thém either in con- ta€t or apart: the wet body will grow lighter in a fhort time, and the dry one will gain more weight; this procefs may be pro- longed, until the two fubftances find the equilibrium of their attractive powers; which will be accomplifhed, when their refpedtive weights become ftationary. This equilibrium proves the 5 oe Ss ae - a oe ae a ee ee ee Bit ON Sa 0s ie ATTRACTION OF WATER BY AIR. - 945 the hygrometrical attra@tion to diminifh with the abforption of water, and to increafe with the lofs of the fame; confequently an union produced by this force, may be diffolved by the pre- fence of a body, which contains lefs water, and therefore at- tracts it more pow erfully. Atmofpherical air may be concluded to nottals the power Atmofpherical defcribed above, from the changes and effeéts, which are ob- #* ao this fervable in the following inftances: Firft, Atmofpherical air itis ng takes the water of cryftallization from various falts ; it theres fore overcomes the affinity, which unites the component parts of thefe cry{tals, Secondly, The fame hygrometer denotes a greater degree of humidity at one time, than at another, though the height of the thermometer be the fame; confe- quently the hygrometrical attraétion of the atmofphere is vari- able under equal degrees of temperature; becaufe this force is evidently conftant in an inftrument kept in an uniform heat, Third, If two veffels be expofed, at the fame time to the air, one of which contains dry potafh, and the other a dilute folu- tion of the fame; the former will acquire weight, while the other grows lighter. The laft faét thows, that atmofpherical air may be faturated with moifture, in refpect of one body, ots and bs at the fame time in a very different fituation relative to another; fo that evaporation evidently arifes from an excefs of hygrometrical attraction in the atmofphere; on the contrary, the produ@ion of dew depends upon a fimilar excefs in the bodies on which it is formed. I may be afked, after making this open declaratian of my Atmofpherical fentiments, which of the conftituent gafes of the atmofphere air 9 fimple gasy _ eombine with water? The proper reply to the queftion appears to be this: It is atmofpherical air; which I confider to bea . homogeneous gas, for the follerivine reafons:—Firft, The at- becaufe it is mofphere is diaphanous; which could hardly be the cafe, were diaphanousy it a mafs of uncombined fluids of different {pecific gravities ; for, had fuch an arrangement been formed, the rays of the fun would have fuffered a multiplicity of refraétions, in their approach to the earth; and total darknefs, or at beft a dim twilight, would have ‘sek the confequence, had our planet been fhrouded by a covering of heterogeneous gafes. Thus the atmofphere appears to be homogeneous, from the confi- deration of its trarifparency.—Secondly, A given meafure of becaufe frart reports are not oxigen is heavier than an equal bulk of azote, under fimilar double to fenfe. circumftances 5 246 ATTRACTION OF WATER BY AIR. Atmofpherical cireumftances ; confequenily the denfity of the former exceeds air 2 fimple 8+ (hat of the latter, fuppofing their elaftic forces to be equal. On this account founds will move, in all cafés, with lefs ce- Terity in oxigen than they do in azote. If then our atmofphere confifled of two independent maffes of thefe fluids, mutually ~ pervading each other, every momentary report would have been double to fenfe, at a fufficient diftance from the feat of found; becaufe fuch a report would arrive at the ear more ex- peditioufly through the medium of the azote, than it would through that of the oxigen. But founds of the fhorteft duration are not repeated at the greateft diftances; confequently the air is homogeneous, becaufe it is the vehicle of found. If the preceding arguments be juft, the homogeneity of at- mofpherical air cannot be controverted ; becaufe the conclu- fions which refult from the contrary hypothefis are repugnant to common experience. We come in the next place to the {pecific nature of this gas; but this is a difficult enquiry in the prefent unfettled ftate of chemiftry, when the phenomena of galvanifm are daily bringing new truths to light, and threaten to fubvert the prevailing theory. Conjeélures, however, will naturally {pring up in the midft of uncertainty; and asa di- verfity of fentiment has its ufe in times of fcientific anarchy, I will venture to propofe the following hypothetical queftions relative to the confitution of common air. Is not this fluid a chemical compound, having the gas called azote for its bafis; to which the pofitive energy of the galvanic pile is united, to- gether with water, but in a manner which diftinguifhes this compound from the gafeous oxide of azote? May not a gas, thus conftituted, oxidate other fubftances through the interpo- fition of the water, which it holds in folution by the hygro- gz metrical attra@tion? Though the aqueous part of the atmof- ~ phere cannot of itfelf decompound common air; may not it perform the office of an intermediate agent, when affifled by — the body to be oxidated, and in this manner deprive the azote of the galvanic energy, more or lefs perfeétly, according to circumftances? Will not the aqueous vapour unite with the matter feparated from the air, and produce oxigen gas, which will enter into compofition with the third fubftance, and com- — plete the bufinefs of oxidation? The hints fuggefted in the preceding queries, would have been by no means admiffible — a én atime of more perfect uniformity in the fentiments of phi- | lofophers; | ARSENIATED COPPER. lofophers ; and nothing can be pleaded in its excufe but the revolution of opinion, which is apparently ready to take place in the theory of gafeous fluids. eS ae ad IV. Reply to the Obfervations of M.V Abbé Hauy, on arfeniated Cop- per. By M.1e Comte ve Bournon, Member of the Royal and Linnean Societies of London.* 247 Ir is but a few days, Sir, fince I had the honour to recéive Introductory from you the obfervations which you have made on the differ- ent {pecies of arfeniated copper, defcribed by me, in a memoir on that fubje@, read to the Royal Society of London, on the 19th of February, 1801. I have read thefe obfervations with the greateft intereft, but not being able to adopt the opinion refpeéting them, to which the inveftigations you have fubmit- ted them have led you, I feel great obligation for the oppor- tunity you have afforded me of explaining myfelf more parti- cularly than I have hitherto done, on what relates to this ins terefting fubje@&. Befides, you offer thefe obfervations with that diffidence which ufually charaéterizes real merit, accom- - panied with a doubt which calls for a new examination. You oppofe my opinion, Sir, on the divifion which I have made of the arfeniated copper into four fpecies, with a deli- cacy and a politenefs, which renders the flight mineralogical difcuffion that becomes the neceffary refult of it, of infinite value to me. It is very defirable that thofe faéts on which differences of opinion may prevail fhould always be difcufled in this manner: the fciences would certainly gain by it, and thofe who cultivate them would lofe nothing by yielding a lit- tle to each other. remarks, Like you, Sir, when I employed myfelf on the fubftance Notice of the which, fince the firft effays of the celebrated Klaproth on Ree ee has been called a combination of the arfenical acid and cop- per, I thought it right to confider, under the fame point of view, the different cryftalline forms which it offered, deriving them all from one common bafe, and my firft enquiries were * Tranflated from the original, communicated by the author. For the paper of the Abbé, fee p. 187 of our prefent vol. ot direfed ‘ 948 ARSENIATED COPPER, direéted to determining this bafe, or the primitive generating cryftal of all thofe of this fubftance. -I was not long in dif- covering that among the cryftals which I had fubjeéted to this examination, there exifted two forms which could not, in apy way, be conneéted with the others: analyfis has fince fhown, that one of thefe belonged to an arfeniated iron, which had been improperly cited as belonging to copper, and the other to a combination of copper and iron with the arfenical acid, which had not been known before. With refpeét to the cates cryftals, as the appearance offered by each of them contradiéted the opinion which conneéted them, it became neceflary to de- pend in the beft poffible manner on all the other exterior cha- raclers which this fubftance could offer to the mineralogitt, to attain to fome refult refpeGing it. This is precifely what [| have done, and when the aggregate of thefe charaélers forced me to recognize four very diftinét fpecies in the mafs of fub- ftances, which I fufpeéted might belong to the combination of the arfenical acid and copper, I confefs I experienced fome fatisfaGion in obferving that the analyfis of a chemift, fo juftly efteemed as Mr. Chenevix is, fanétioned, in fome meafure, the divifion to which obfervation had led me. You remark, Sir, that thefe analy fis, on being repeated by M. Vauquelin, varied in their refult: it follows neceffarily, that this fupport fails, or at leaft becomes uncertain for me: x abandon it there- fore, and leave to chemiftry the difcuftion of a faét which be- longs to it, and was to me only a powerful auxiliary, to con- fine myfelf within the ftriét limits of mineralogy propérly fo’ called. Preliminary ob- But allow me, Sir, firftto make fome previous obfervations fervations on the on the method which, it appears to me, fhould be followed to guiding infu determine the union or feparation of fubftances, and after- logical enquiries. wards, on the poffibility of finding feveral {pecies placed under the combination of the fame-acid with the fame bafe, but with- out doubt, having effential differences in the manner of com- bination. The methods to be employed by the mineralogift in the ftudy of mineral fubftances, are comprized in the examination of the peculiar marks which nature has impreffed on each of the in- dividuals which decorate and enrich its bofom, and which his great habit of obferving has taught him to recognize. Of thefe marks, which we defignate by the exprefiion of exterior {pe- cific ARSENIATED COPPER, cific charaGters, fome are too delicate to be deferibed; but cuf- tom enables the naturalift to feize them ; their aétion on his fight is fudden ; the moft rapid glance embraces the whole of them, and the naturalift has frequently formed his opinion long before he has thought of accounting to himfelf for it. He is not, however, fecured by them from the errors which other bulkier and more comparable charaéters may afterwards rec- tify; but the firft impreffion received from thefe firft traces, very often ferves him as a guide in the method of employing the fecond, Among thefe latter charaéters, fome are of eafy application and almoft always poffible, others require attention and particular circumftances to be capable of being employed. Thofe which are in moft common ufe, and eafieft, are the form, the fraéture, the hardnefs, the fpecific gravity, and the colour. ~ Perhaps in a fkilfal hand, directed by the habit acquired from their ufe, thefe charaéters are almoft always fufficient for the knowledge and claffification of mineral fubftances. In ftones, the colouris the moft variable of all : neverthelefs, it is certain, ibough the true caufe cannot yet be affigned, that each of thofe which have been examined hitherto, affe&ts one only of the known colours more readily than it does any of the othabs: But in the metals this charaéter becomes more conftant and -more effential, and it very feldom varies without the caufe of its variation being a change in the nature of the metallic fub- ftance itfelf. This faét granted, when the naturalift employs the exterior fpecific charaéters, to afcertain the fubjeét which determines his enquiry, from the moment at which the agreement of thefe -eharaéters, or their differences with thofe fhown by known fubftances, puts him in a fituation to pronounce on the identity or the difference of their nature, do not you believe that he has _ then the liberty of retrenching, on the one hand, thofe which do not agree with the opinion which he had previoufly thought jt right to embrace; and, in the fecond place, to fubjeé the others to fuppofitions which may occafion a change in their afpe@ to conneét them with that which he wifhes, when na- ture itfelf has not offered traces, free from doubt, of the pro- bability of the modification which he admits in thefe charac- ters? - Permit me to obferve to you, Sir, that this is precifely what appears to me to be the fubftance of your obfervations on the arfeniated \ 249 The confidera- tion of fome of the charaéters may be omitted when they do not lead to gee neral inferences, This has been a M.. 250 ARSENIATED COPPER. arfeniated copper. You feem to confider as nothing the very’ fenfible differences. which exift in the divers fpecies which I have eftablifhed, with refpeé to hardnefs, {pecific gravity, and colour ; and, ftopping at the fingle charaéter of form, you make fuppofitions for each of them, which, in fact, terminate by connecting all thofe which they offer with one primitive cry- ftal: but nature does not exhibit any of the decrements which you fuppofe. I have never difcovered the flighteft trace of them in any of the immenfe quantity of cryftals of arfeniated copper which have paffed through my hands. Do you believe that thefe fuppofitions are only fufceptible -of being admitted in acafe in which, all the other charagters being agreed in the moft perfeét flate of thefe fubftances, which is that of regular cryftallization and.tranfparency, they would become neceflary only to add an accumulation of proofs to thofe already ac- quired of their identity, Exact diftinc- Never was more attention paid than at this moment to the tion of the fpe- sreat truth, that the progrefs of the fciences which lead to the cies neceflary to ais Apes Niels _ the progrefs of {tudy of nature, depends principally on the exaét diftinétion of the fcience. each of the fpecies whofe union forms the aggregate to which the {cience is applied. No one is more convinced of this im- portant truth thanI am, But this exact knowledge of the fpecies, which perhaps your calculation or the analyfis of im- proved chemiftry may one day attain in a fimple and accurate manner, refts at prefent on the agreement of the exterior {pe- cific chara@ers. Whenever this agreement exiltsg we are compelled to conclude that there is a fimilitude in the fpecies, and, on the contrary, a diffimilarity when they differ effen- tially trom each other. I, however, agree perfeétly with you, that before feparating one of thefe fubfances from the other to make a fpecies of each, it is requifite to be previoufly con- vinced that the differences which they offer, and on which their divifion refts, are not purely accidental. It appears to me, therefore, that nothing can be more undeferving of the re- proach of having negleéted thefe precautions, than, on the contrary, the eftablifhment of the divifion on the invariable conftancy in the difference of their exterior charaéters. Chemical analy- The only reafon, which, in the fubftances in queftion, can ‘sah ata raife any doubt on their difference, is the refult obtained from mineralogical them by chemical analyfis, which conftantly found the arfeni- charaéterss cal acid combined with the copper in each of them; but if the — analyfis SE ee es eee ARSENIATED COPPER. analyiis had not been poffible, certainly no naturalift would have hefitated to feparate them from each other, according to the exterior charaéters fhown by each of them. Why therefore, becaufe thefe fubftances all belong to the combination of the fame acid with the fame metal, fhould there not ‘be found feveral fpecies among them? This, I be- lieve, is a faét which occurs much more frequently than has been hitherto fuppofed. Do not all the metals fhow various inftances of ftriking differences in the oxides, in confequence of that which exifts in the combination of oxigen with them? The ogtahedral attra&tive oxided iron, that which is rhomboidal that not attra@tive, are not all thefe fo many f{pecies? In a me- ‘moir which was inferted in the 75th number of the Journal des Mines, 1 have endeavoured to fhow that the o@tahedral ful- phurated iron, and that in cubes, formed two very diftinét fpecies, and I do not believe that thefe are the only ones whith exifl in it. How many fpecies are offered by fulphurated cop- _ per! Tam myfelf acquainted with fix, all perfeétly diftinét and charaéterized, which I have long intended to give the defcrip- tion ‘of, but ‘my occupations and want of time have not yet permitied me. Finally, have not you yourfelf been compelled to form a particular fpecies of carbonated lime, of the arra- 251 » Variations in the fpecies of the fame che- mical ¢ombina- tion. gonile; from the difference alone, which exifts in its exterior {pecific charaéters, although chemiftry can only find carbonic acid and lime 1 in it ? One reafon which may be alledged againft the divifion of arfeniated copper into {fpecies, is that the combination of cop- - per with the arfenical acid being already a fpecies in the genus of ores of copper, it would be making {pecies of a {pecies: and this objection, w hich at the firft bluth appears well founded, would bear equally againft the various oxides, fulphurets, &e. But this difficulty. ‘Sie to me (o be more fpecious than folid: it takes its rife from the impoffibility in which we ftill are of afcertaining every thing connected with the different caufes which may produce a variation of the fpecies. Without doubt, in this inftance, for example, it is not the fimple combination of the arfenical acid with the copper which forms the fpecies, but the particular combination of this acid with the metal. Thus it is not the fimple combination of oxigen, hidrogen, carbon, azote, &c. which conftitutes the particular fpecies of animal, but the manner of the combination itfelf. Pg: ) | The 952 : ARSENIATED COPPER. Mineralogy is The mineralogical {pecies are very accurately determined a ee by the agreement or difference which exifts in the firft mole- toadmitofthe cule of the formation of the different fubfiances, but until we cigar ei have fixed data to appreciate, in a determinate and invariable pe of th manner, all which relates to thefe molecule, the conftancy or primitive mole- {\ie difference in thefe exterior {pecific charaéters will always cule HOM? be’ the only means within our power of uniting or feparating . the fpecies, I acknowledge, however, that in this cafe, it is neceffary that this divifion fhould be eftablifhed as much.as pof- fible on firiking and effential characters; and I agree, at the fame time, that latterly, this method has perhaps been much abufed by giving importance to fimple and cafual charaéters; this has frequently placed fubftances in the number of fpecies, which fhould only have been confidered as bey varieties of thofe already known, I fhall now beg of you, Sir, to compare wail me the differ- ent fpecies of arfeniated copper which I have defcribed, Comparifon of the Firft and Second Species. Comparifon of § The form of the firft fpecies is an obtufe reétangular o€ta- the firffand ~~ hedron, whofe faces are unequally inclined. Two of them fecond fpecies of ‘ arfeniated cop- meet at the fummit under an angle of 139° and at the bafe pete under one of 50°. The two others meet at the fummit in an angle of 115°, and at the -bafe in one of 65°. This oétahe- dron is ufually cuneiform: I have never perceived any modifi, ° cation of it. The form of the fecond fpecies is a hexahedral plate, always very thin, whofe vertical planes are inclined alternately in op- pofite dire@ions, fo that two of them, on the fame fide, make — | an angle of 135° with the terminal faces to which they incline, and the third, one of 115°... teh job ids The moft ufual colour of the firft {pecies isa deep and very brilliant fky-blue, which fometimes changes to green, That of the fecond fpecies is a fine emerald green: I have never feen any other. The fpecific gravity of the firft {pecies is 2831: that of the fecond 2548, -. The hardnefs of the firft is fuch that it readily cuts carbon-" “’ ated lime: the fecond is no harder than is fuflicient to cat gypfum. ARSENIATED COPPER. 953 ‘In your obfervations, Sir, you have raifed to 50° 4’ and 65° 8’ the meafures which I-had eftablifhed at 50° and 6593 meafures which you have fixed from the relations eftablifhed by you between the height of one of the pyramids and the per- pendiculars drawn from its bottom on the edges of its bafe, which correfponds with the adjacent and unequally inclined, pyramidal faces. Thefe meafures are fo near to mine, that I have proved them again, and the inftrument is fo little capable of marking this difference, that I do not make any difficulty in adopting them. To conne& the form of the fecond fpecies with the obtufe oGiahedron of the firft, you afterwards fuppofe two fe@ions made parallel to one of the moft inclined faces of the o¢tahe- dron, fo as to detach a very thin fegment, in which the centre of this o€tahedron is to be contained; that is to fay, this ota. hedron is to be confiderably increafed on all its faces, with the exception of one alone, taken on each pyramid, and in an oppofite direGtion in each of them. You fuppofe at the fame time a decrement of a fingle row along the edges of the bafe, but which aéts only on two of the faces of the o€tahedron, and that the fegment which refults on two of the three fides inclined to each of the terminal faces, makes with them an an- gle of 1302° and the third 115°, meafures which only differ ', 5° 30’ in the angle of 130% 30’ from thofe which I have given . for the cry ftal. The following is the anfwer diétated by the new examina- tion which I have made of this fubftance. _ Agreeably to what I have faid in my memoir on the arfeni- Objeétions to ated coppers, the obtufe oftahedron frequently thows eh eel tla _ ftreaks in its faces parallel to its edges, which indicates a la- mellated texture in the dire@tion of thefe faces. The fra@ure ' alfo indicates the fame texture, but its fraétures are always ' more or lefs irregular. I have never been able to obtain a clearone. In the fecond fpecies, on the contrary, the lami- nae are as eafily raifed from the hexahedral terminal faces, as could have been done on a prifm of mica. ‘Thefe terminal ces are fometimes ftreaked parallel to the edges of the fides ' which are inclined to them, and thefe ftreaks, which are conti- nued firongly on the fides, never appear upon them except in this dire€tion. This texture, very analogous to that of mica, feems to me to be totally different from that of the obtufe oc- - tahegron of the firft {pecies. I have Q54 ARSENIATED COPPER. I have fubmitted fome new cryftals of this fpeciés to mea- furement, and have found them agree perfeétly in the meafures of 115° and 135° with thofe which I had examined before. The angle fuppofed by you of 130° 30’, which I have tried on” a number of cryftals always appeared ‘to me to be much too A new variety of {mall. Thefe cryftals have offered me a new variety, in which ripe the fides of the hexahedral lamina are lefs inclined on the ter- sees minal faces, with which they form an angle of about 105°. The cryftal which afforded me this new variety is four lines in diameter: it is only in perfeét prefervation in one of its halves, but it admits of a judgment from it, that all its fides muft have the fame inclination. Thefe new faces are perfe@ly fmooth, and do not fhow any ftria. On another cryftal, inftead of thefe inclined fides, two planes are obferved, one of which belongs to that which made an angle of 105° with the termi- nal face to which it inclines, and the other belongs either to’ that of F15° or that of 135°. There was not any thing that I could difcover connected with any of the planes of the obtufe o€tahedron of the firft fpevies. bd Comparifon of the Third Species with the Firft. . Comparifon of | The colour of the firft is either a deep fky-blue or a grafs~ Tae ana eee That moft ufualin the third is a yellowifh green, more’. or lefs deep, but very frequently it can only be perceived by placing the cryftal between the eye and the light, the intenfity of the colour making the cryftals appear black in every other, pofition. : The fpecific gravity of the firft is 2881; that of the third — 4280. The hardnefs of the firft is not more than fufficient to feratch carbonated lime; that of the third is fuch as to cut fluated lime. The firft fpecies bas an obtufe re@angular oétahedron for a unique and primitive cryftal, whofe dimenfions have been — given above: the figure of the third is an acute re@tangular o@ahedron, in which each pyramid has two faces more ine _ clined than the other two; the two moft. inclined faces meetys at the fummit, in an angle of 84°, and at the bafe in one - 96°, and the two others meet at the fummit in an angle of 68°, and at the bafe in one of 102°. This ofahedron is moft ufually cuneiform, and its prolongation is fometimes very confi- derable; 4 ARSENIATED COPPER. 255 derable; it then takes the appearance of a rhomboidal tetrahe- dral prifm of $4° and 96°, terminated at its extremities by a _ dihedral fummit with ifofceles triangular planes, the faummit of which is placed on the edges of 84°, and the bafes meet with each other inan angle of 112°. This form has not hitherto fhown any other modification except being replaced by a plane, larger or fmaller, on the edges of 96°. Its planes are ufually very fmooth and brilliant, and I have never been able to dif- cover an appearance of divifion (clivage) in any of them. This third {pecies paffes by the greatly lengthened o€tahe- dron to the determinate capillary variety, as well as to that which is indeterminate, and in this cafe the colour appears either to fend more to green or to take a more defined yellow, which fometimes has the brilliancy of gold. The firft fpecies does not exhibit any thing which refembles thefe various tranfitions; it is always the fame obtufe oétahe« dron, and only varies by a very flight prolongation of its cryftals _ parallel to the leaft inclined fier. 4i(E'e wake abe ferchation of _ the acute o€tahedron of the third fpecies, fecondary to the ob- _ tufe one of the firft, you fuppofe a decrement at the bafe of _ the latter of two rows above and below the edges of the union * q of the leaft inclined faces, and another of fopr rows at that of the union of the moft inclined faces, and by this, you get an { acute o€tahedron, whofe moft inclined faces meet at the fum- _ mit, in an angle of 86° 24 and at the bafe in an angle of a 93° 36’; and the others meet at the fummit in an angle of 71°, ' and at the bafe in one of 109°. A I acknowledge that this approximation to the meafures which I have given is feducing, and, confidering the natural fmallnefs of the cryftals of this {pecies, it would perhaps be difficult for me to pronounce determinately whether the mea- -fures which I have taken are much more exaét than thofe to which you have attained by calculation; but this I can affure | you, that no indication whatever, in either of thefe two o¢ta- hedra, leads to the fuppofition which has tie you this re- fault. _ From the details I have now given, it is eafy to deduce the Reafons for , reafons which impel me to adhere to the divifion which I have bem ibe f thought it right to make in the arfeniated copper, and prevent {pecies. _me from adopting the approximation to which your ingenious hypothefes have led you. Every thing ftill feems to me to tend 3 to i ke ¢ ‘a i 4 Wy in ‘ i 256 ARSENIATED COPPER: to indicate a difference in the fpecies into which I have fepae rated them, while to bring them to a fingle one, you have beer obliged to confider as nothing; all the exterior {pecific characs ters, with the exception of the form alone, and you have ufed the latter only in eftablifhing an hypothefis refpeéting it, to which, neither artificial means, fuch as fplitting, nor natural mdications, fuch as fecondary planes on a primitive cryftal, nor the retaining of primitive planes on the others have led you. If in the explanation of embaraffing faéts, it were permitted thus tomake nature fpeak when fhe is filent, I have no hefi- tation in afferting that a naturalift fo well informed, and fo pradtifed in the art of calculation as you are, would: find very few obftacles in refolving allthe fpecies into each other when- ever he chofe. _ Of the four fpecies of arfeniated copper which I have des {cribed, there ftill remains one; in refpeéct of which you have not made any calculation of approximation; it is the fourth, which, as I have ftated, has for a primitive cryftal a tetrahe- dral prifm with an equilateral triangle for a bale. Neverthelefs you do not exclude it when you draw your conclufions on the doubt which you believe to exift on the divifion of the arfeni« ated coppers into four {pecies, and you direét this doubt equally to the fourth. Since according to your fuppofition this can only be as a primitive to the firft cryftal, that it may alfo be in a ftate to be brought to it, I have thought it right to add likes wife the comparifon of this fourth fpecies with the firft. Comparifon of the Fourth Species with the Firft. Comparifon of The colour of the firlt {pecies is a deep fky-blue, which fome« the fourth times changes to grafs-green. That of the fourth is a brilliant {pecies with the, eae ‘ : ; oF Firth deep verdigris, but its furface is very readily difcoloured, doubt- Jefs by oxidating, and it then becomes black: this renders the cryflals opaque, which, when they have not experienced this alteration, are beautifully tranfparents this is very unufual among thofe which have been naturally expofed to the free air’ during a certain time. This change however exilfts only at the furface; by feratching the cryftals lightly, their fine colour is readily reftored to them. I have never perceived any thing — refembling this faét, which unqueftionably depends on the naz — ture of the fubftance of this fpecies, either among the cryftals of the firft, or among thofe of the fecond and third, The : SEPARATION OF ALUMINE. 961 To prove what has been ftated before, let any quantity of The precipitate the obtained alumine be heated in conta& with charcoal pow- ib uaeae ae der; introduce the mixture into a tabulated retort, conne@ted with charcoal, with the pneumatic apparatus, and add to it muriatic or ful- eee Raragin phuric acid; the refu!t will be fulphuretted hidrogen gas in gives fulphuret- abundance, particularly if heat be apphed to the mixture, ©¢ hidrogene _ The produdion of this gas will become evident on confidering the philofophy of the procefs, By means of the following method, alumine may be obtained in a purer ftate. Take any quantity of alum of commerce, diffolve it in four Method of parts of boiling diftilled water, and mingle this folution with Seta pe liquid ammonia till no further cloudinefs enfues, Then heat ; the mixture nearly to the boiling point for a few minutes, and transfer it on a filter. In proportion as the fluid paffes off, Precipitate by pour more water over the precipitate, and continue the ablu- Ci aak rk tion till the water runs off taftelefs. Having done this, let the folve in muriatie ctw F - . acid. Evaporate precipitate while yet ina pafty ftate, be transferred into a ba- 4" cryltaliiae - fon or flafk, and add to it muriatic acid, in fmall quantities at for a contami-. a time, until the whole is diffolved; then evaporate the folu- hating portion : : s ; : of alum. Then tion till a drop of it, when fuffered to cool on a plate of glafsy dilute and pre _ yields minute cryftals. If it now be fuffered to cool, cryftals . 9d, That the zinc and manganefe which precipitate the cops per, neutralize the acids better than it *. * By neutralizing the acids more or lefs, I. meai that property poffeffed by the metallic oxides, and fome earths, fuch as glucine and alumine, of approaching more or lefs, in their comb: nations with the acids, to the term of neutralization. Vow. VIII.—Aucust, 1804, "y 3d, O74 MUTUAL PRECIPITATIONS OF METALLIC OXIDES. 3d. That the oxide of filver which precipitates thofe of zine and copper, neutralizes the acids better than them. Alumineis pre- If, befides, we reflect, that alumine, whofe folutions are cipitated by me- ees bes * : ; tallic oxides; V@FY acid, is precipitated by feveral metallic oxides which neutralize the acids better than it; that, according to the ex and by glucine. periments of Vauquelin, glucine decompofes aluminous falts, and that its folutions are more neutral than thofe of alumine, Magnefia preci- although they are not entirely fo; and, finally, that magnefia, pitates the earths which neutralizes the acids perfe@ly, precipitates the pre- ceding earths, and a very great number, not to fay all, the oxides from their folutions; we cannot abftain from allowing that, if the property poffeffed by the metallic oxides and feve- ral earths of neutralizing the acids unequally, is not the only caufe of the decompofitions which I have detailed, it is at leaft one of the principal. The afinity for We may alfo conclude from the fame experiments, that the acta the metals which have a great or a weak affinity for oxigen, do not enjoy any particular property with refpeét to their mutual precipitations; for we fee that iron, in a ftate of great oxida- tion, is ‘precipitated by a number of oxides which it precipi- tates when it is lefs fo; and, that there are feveral oxides which contain lefs oxigen than that of zinc, which precipitate the latter, while there are others which are precipitated by its The affinity of the different metals for oxigen is therefore rejected as the caufe of the mutual precipitations of their oxides; but can the greater or lefs oxidation of the fame metal occafion a variation in the affinity of the oxide for the acids? This opinion has been promulgated by Cit. Berthollet in his The ftate of the Chemical Statics *, and he has grounded it upon feveral faéts, pnenesghs ies in which the metal, by lofing a little of its oxigen by any nity of the ox- means whatever, forms another falt with lefs acid. This hap- ides forthe hens to the oxigenated muriate of mercury, which, by expo- acids 5 ; : see Pee ae ee fure to light, or by being brought into contaét with iron, is changed into white muriate by abandoning fome of its acid.’ Although thefe, and other fimilar faéts, are capable of a dif- ferent interpretation, other confiderations, which I fhall omit here, becaufe they would lead me too far, induce me to par- ticipate in the opinion of Citizen Berthollet ; but I do not be-. '* A tranflation of which will be publithed by Mawman, in the — Poultry, about the middle of the prefent month. lieve a ee ae ee a MUTUAL PRECIPITATIONS OF METALLIC OXIDES, Q75 lieve that this caufe can have much effe@, it being ftrongly counteracted by the acidity which almoft all the metallic folu- tions poffefs, and by the infolubility of the oxides. -Thus, although it appears to me that iron, when little oxided, has more affinity for muriatic acid than when it is greatly oxided, I thould rather attribute the precipitation of the latter by the former to the great excefs of acid which its folution requires, than to its weaker affinity. Neither, for the fame reafans, do I believe that the affinity but is not the of the different oxides for the acids, an affinity which I mea- °c" of their fure, with Cit. Berthollet, by the capacities for pudvatiotyane. ee can be confidered as the caufe of their mutual precipitations, Befides, there is one confideration of fome importance which Influence of the fhould be taken into the explanation of the mutual precipita. *e#ined acids tions of the oxides; it is that, in a cafe where the precipita- tion of a metallic folution is produced by means of an alkali, the precipitate retains fome of the acid which can favour its folution; fo that an oxide which could retain much of the ‘- acid, would diffolve more readily than that which could only retain lefs, It muft really be fo with iron, which, when it is precipitated from a green folution, retains much more acid than when it is precipitated from a red folution, and which diffolves much better in the acids in the firft cafe than in the fecond. This more ready folution cannot, however, be confidered as a caufe of the mutual precipitations of the metallic oxides ; it may be very favourable to them, but cannot determine them. In faét, we fee that the oxide of copper, which retains much acid, is neverthelefs precipitated by oxide of filver, which does not fenfibly retain any, when they are precipitated from their nitric folutions by potafh. CONCLUSION. THE metallic oxides are mutually precipitated from their General infer folutions. Several canfes may contribute to this; but among "°“* the number of the principal muft be placed the property which they have of neutralizing the acids unequally. This property has furnifhed us with the means, 1/. Of freeing a green folution of iron from the red oxide which it may contain; 2d. Of feparating the fulphate of zinc and that of copper from the iron which is always found in them; 3d. Of having a green fulphate of iron free from copper; 4th. Of . T2 readily 2716 MUTUAL PRECIPITATIONS OF METALLIC OXIDES, General infer- readily feparating the copper from a folution of filver. It is CNCESe eafy to accumulate thefe applications by extending them to a greater number of fubftances. Thus, the oxides of cobalt and nickel do not neutralize the acids equally; that of the two which neutralizes it moft, will be able to precipitate the other, and remain alone in the folution. Thus, alfo, fince glucine neutralizes the acids much better than highly oxided-iron, it will be eafy to feparate this metal from its folutions, by firft oxidating it ftrongly, and afterwards precipitating one part of the folution, to employ it, after being well wafhed, to pre- cipitate the iron of the other part. The greater or lefs affinity of the metals for oxigen does not give them any particular property with refpeét to the mutual precipitation of their oxides. . _ Oxidation produces a variation in the affinity, or the capacity for faturation of the oxides for the acids; neverthelefs, the re(ults are only fenfible inafmuch as they produce a change in the neutralization, and in this cafe they may be attributed to , the latter caufe. The affinity of the oxides for the acids may indeed con- tribute to their mutual precipitations, but its effects are very limited. . It appears, therefore, in general, that, all circumflances remaining otherwife the fame, the fubftances which neu- tralize the acids beft, may precipitate the others from their folutions. I repeat in concluding, that it is only on the fa&ts which I have related that I have eftablithed my reafoning, and that it was not my object in ths note to {peak of the precipitations by the metals, nor of thofe which are owing to the reciprocal action of the oxides, or to that of the latter and the alkalis. A Report HIS MAJESTY’S FINE WOOLED SPANISH SHEEP, Q77 IX. A Report of the State of his Majefy’s Flock of Fine Wooled Spanifh Sheep, for the year ending Michaelmas, 1803. By the Right Honourable Sir Josepu Banks, Bart. P. R. §. Se. &c. From the printed Copy communicated by the Author.* Tur wether lambs of the laft year having been fold in their State of his Ma- wool, and the rams wool retained, in order that two years growth neal ponding might be prepared for fale together, his Majefty’s Spanifh flock Fie 1802. confifted, when fhorn in June 1802, of ninety-fix ewes only ; the fleeces of thefe, after having been wafhed on the fheeps’ backs as ufual, weighed as follows: In wool, as thorn from the fheep - - 352 lbs. Lofs in feowering rel ete a 96 oe Amount of fcowered wool - - - 256 This wool, when forted, produced as follows: Prime wool, or R. 221 lbs. at 58. 9d. £.63 10 9 Choice locks, or F. 32 al ¢ =) 5 12°06 Fribs, or T. - 3—-—1 9 «| OD av 2g £.69 8 O After dedu€ting the expence of forting and fcowering, at the high rate which an individual who is not a manufa€turer “muft pay for thefe proceffes, this wool is worth about 51. a tod, or 431. 5s. a pack, as clipped from the fheeps’ back, The prime wool was purchafed by John Maitland, Efq, Sale of the member of parliament for Chippenham, whofe mercantile Ys houfe, eftablifhed for more than a century, has always dealt largely in the importation of Spanifh wool, and who from the firft introdu@ion of Merino fheep into this country by the King in the year of 1787, has uniformly given the moft liberal and _ zealous aid to the promotion of his Majefty’s patriotic views, though doubtful in the beginning of the ultimate fuccefs of the project. * For the original project of this important undertaking and its fubfequent progrefs, fee the former reports by the fame Right Hon. Gentleman, inferted in our Journal, quarto, vol. IV. p. 289, and gstavo, vol. V. p. 65. ; 278 HIS MAJESTY’S FINE WOOLED SPANISH SHEEP. manufactured It was made into cloth by Mr. Edridge, a manufa@turer of ~ into cloth; = Chippenham, whofe {kill and refpeétability in his line is ex- ceeded by no man. He infpeéted its quality with the moft minute exaétnefs, and with an eye more inclined to expect fymptoms of degeneration than of improvement, during the whole of the numerous proceffes to which wool is fubjeéted in the making of broad cloth, and he found that in every one of them it anfwered to his complete fatisfaétion. The cloth made from this wool proved fo excellent in its kind, that the King was gracioufly pleafed, at the defire of Mr. Maitland and Mr. Edridge, to permit thefe gentlemen to explain, in his Majefty’s prefence, its qualities and pecue liarities. of which famples Samples of this cloth may now be feen in Mr. Maitland’s maybefeens — Warehoufe in Bafinghall-ftreet ; and it will be found, in con- verfing with Mr, Maitland and his partners, that in their opi- nion the R.’s of his Majefty’s wool, confidered as a pile, are inferior to but few of the beft of thofe imported from Spain, though it is probable that no pile in Spain throws out fo fmall The wool has a proportion of F.s and T.s. From this opinion it may fairly tiaiprcnet- be deduced, that his Majefty’s wool has improved fince the fheep were imported from Spain; indeed there is every reafon to believe that it is Rillimproving, and willin a very few years equal if not excel the very beft piles that have hitherto been . imported into this kingdom. Improvement of | Mr. Tollet, a gentleman of Gloucefterfhire, whe has pur- the carcale of Chafed Merino fheep both from the King and from Lord Merino theep, : ora by Mr. Toilet, Somerville, has been very fuccefsful in improving the carcafe t lb eg without damaging the wool; he poffeffes aram, .bred froma aging F i ters | ram and a ewe both purchafed from the royal flock in 1801 ;_ which, when clipped in June laft, yielded 11 lbs. 12 oz. of unwafhed wool. The carcale of this fheep was then eftimated by good judges at 16 lbs. a quarter, and it was admitted to be a handfome fheep. — For this animal Mr. Tollet has refufed an offer of 200 gui- neas, or of 100 for the next feafon’s ufe of him; he alfo re- fufed 30 guineas each for the fire and the dam, though old and infirm, being unwilling to part with animals which had belonged to the royal flock ; he however fold their ram lamb of the att P year for 30 guineas, and thus made fome progrefs in afcer. | taining the value of this important breed, a Thefe — WIS MAJESTY’s FINE WOOLED SPANISH SHEEP. 979 Thefe faéts, which prove an ached in the King’s Senos by Merino fheep, are fully confirmed by the improved fhape and er a ai weight of his Majefty’s fheerling rams of the prefent year,jefty’s flock, ___ and give a juftifiable hope, that bya due feleétion of rams and ewes, and a correét judgment in matching them, Merino fheep will in time be produced, with carcafes perfedlly fafhionable, and wool as perfeétly fine. No purchafer having been laft year found for the lambs wool Lamb's wool. at a price adequate to its value, it was made into light ladies cloth, which proves excellent, and promifes to be a valuable wticle. A fpeculation, however, has offered for manu- faGturing the lambs wool into fuperfine woolen hofe, which | feems likely to yield a ftill better price for the raw article than the cloth. The demand for his Majefty’s Merino fheep increafes at The demand prefent beyond all calculation. The beft informed clothiers in ag, ae Gloucefterfhire, enlightened no doubt by the ufeful labours facts are well | of the Bath Society, aad the valuable experiment of Dr. Parry, ***!hed i as wellas by the Doétor’s, and by Lord Somerville’s publications, are among the moft anxious applicants to purchafe. The Bath Agricultural Society, whofe attention has been moft particularly direéted to the improvement of Englith wool, humbly requefted the King to give them a Spanifh ram, which requeft his Ma- jefty moft gracioufly complied with laft Autumn, and they re- )) turned thanks in the warmeit terms of pb inins gratitude and fatisfa@tion. : As {peculation on the value of Spanifh cen is evidently and render it | on the increafe, anda reafonable probability now appears that igh a a his Majefty’s patriotic exertions in introducing the breed, will diftributed by at laft be duly appreciated and properly underftood, it would sfianbl aieee _ _ be palpably unjuft fhould the views of thofe who with to derive fa fair advantage from the fale of the progeny of Spanifh fheep : purchafed by them from the royal flock, be in future impeded _ _ by acontinuation of the fale of the King’s fheep at prices below their real value. This circumftance having ane {tated to the King, his Majefty was gracioufly pleafed to permit the rams and ewes that are to be parted with from the royal Merino flock this year, to be fold by audion, in the fame manner as is done at Woburn by his grace the Duke of Bedford, and at Holkham by Mr. Coke, en the prefumption of this being the moft likely manner of placing 230 ON THE OXIDES OF.LEAD. placing the beft individuals of their improved breeds in the hands of perfons moft likely to preferve, and further to improve them. JOSEPH BANKS. - Auguft 17, 1803. ‘cua Mt a. gnc: POSTSCRIPT. Pofticript, AS the publication of this report has been delayed by un- avoidable circumftances to fo late a period, it is proper to add, that the wools of 1803 have yielded, both raw and fcowered, much as ufual. The prime or R. of the ewe flock, were fold for 6s, 9d. a pound, and that of the Rams for 6s. 6d. Thefe enormous prices, however, depended on a {earcity of imported Spanifh wool, and are highly difireffing to the manufaéturer ; they ought not, therefore, to be allowed to enter into the wie culation of the grower. Notice of fale of The fheep that can be {pared frien the royal flock will be fold si ees by auétion this year ata barn oppofi ite the Pagoda in Kew-lane, - on the 15th of Auguft next. Notice of the particulars will be given as foon as poffible. “A ke): hea ean st July 10, 1804, : & On the Oxides of Lead. By Tuomas THomson, M, dD. Communicated by the Auihor, : . Great import- Ra on there is no praétical branch of chemical inveftie iy * testo gation of more importance than the analy fis of the metallic oxides + oxides, Almoft every thing relating to the metalline paints and falts depends ypon it; and it involves, either direétly or indireGily, moft of the interefting queftions 1 in the theoretical : department of chemiftry. frft applied with Bergman and Scheele were, I believe, the firft perfons who nie applied chemical analyfis, in the modern fenfe of’ the phrafe, Scheele. to the metallic oxides, Notwithftanding the difficulties with which thefe illuftrious chemifts had to ftruggle, their experi- ments were made with fo much care and fagacity, that they ftill furnifh us with the beft data for afcertaining the compofi- tion of feveral of thefe bodies. No modern chemi has las boured ON THE OXIDES OF LEAD, 98} boured fo {uccefsfully in this department as Mr. Prouft. To Analyfes of him we are indebted for the analyfis of the oxides of dine, Fron iron, tin, copper, antimony, and arfenic. His diflertations are all ftamped with the charaéter of originality, and difplay fo much fkill and candour, that they never fail to command the confidence of the reader, Ifhe fometimes puthes his con- fequences a little too far, he more than compenfates for this by the originality of his views, and the new light which he throws upon every fubjeé that he difenfles, I intend at prefent to offer fome obfervations on the oxides Subjeé of ott of lead, a fubjeét more than once {lightly touched upon by oxides of lead. Prouft, but never fully difcuffed by him. [| truft the difficulty — _ of the fubjeG will plead my excule, if I thal! be unfortunate enough to fall into miftakes, “abe ‘We are acquainted with three oxides of lead fufficiently Three diftin® diftiné&t from each other. The firft is of a yellow colour, and a Fit ewe | forms the bafe of almott all the falts of lead; the fecond is a two others. paint well known by the name of red lead ; the third a brown powder difcoyered by Scheele, and examined more lately by Prouft and Vauquelin. Befides thefe three, a fourth has been announced by Prout; and litharge has been confidered by . fome as conflituling a fifth. Let us examine thefe oxides. ‘ I. Yellow Oxide. The yellow pigment cited mafficot éault fis effentially of this Aad oxide of oxide ; but the eafieft method of forming it, is to diffolve tear” in nitric acid. Pure lead diffolves completely i in that acid; but the lead of commerce ufually leaves a fall quantity of grey powder, which confifts for the moft part of oxide of antimony, fometimes mixed with a little filica. When the folution is concentrated by evaporation, we obtain cryflals of nitrate of lead, a falt too well known to ouaire any par ticular defcription. 1. When the cryftals of nitrate of lead thus obtained by Nitrate of lead, lofes acid by low evaporation, and well dried upon blotting- paper, are expofed ane to a temperature of about 300°, they lofe, at an average, three per cent. of their weight. This lofs is not to be afc ribed to the efcape of mere water, for the fumes {mell ftrongly of pitric acid. 2. When 69 grains of lead are diffolved in nitric acid, and — ae contain- the folution evaporated to etienes the nitrate of lead, after °° * ercine . being 282 Carbonate of lead: white lead. €arbonate of . Jead by heat leaves yellow ON THE OXIDES OF LEAD. being dried at the temperature of 300°, weighs 112 grains. ia 100 grains of lead yield 1622 grains of nitrate of lead. From this we learn that 100 parts af nitrate of lead confift of 612 lead, 384 foreign bodies. od 100. 3. When 112 grains of nitrate of lead (dried at 300°) are diffolved in water and mixed with a folution of carbonate of potafh, a copious white powder precipitates, which is a car- bonate of lead. Bergman thewed long ago, that the white lead of commerce is precifely the fame with this carbonate. When wathed, colleéted on a filter, and dried at 300%, it ‘weighs 90 grains. This fhews us that 69 grains of lead yield 90 grains of carbonate: of courfe, 100 grains of lead would yield 1302 grains of carbonate. From this experiment we learn, that 100 parts of precipitated carbonate of lead are compofed of 76% lead, 234 foreign bodies. — 100, 4, When 90 grains of precipitated carbonate of lead are ex- pofed in a retort to a heat gradually raifed to rednefs, the oxide; 9 lead 4 acid and water which they contain are driven off, and a yellow I oxigen: — very fufible. coloured oxide remains behind. This oxide weighs 77 grains, and contains, of courfe, 69 grains of lead. Hence it follows, that the yellow oxide of lead is compofed of 69 lead + 8 oxi« gen, or per cent, of 89.7 lead, 10,3 oxigen, 100. Itis well known that the oxides of lead very eafily melt and run into glafs. This happens in the preceding experiment, unlefs particular'care be taken. In that cafe the lead aéts with great energy upon the retort; but the lofs of weight is the fame, unlefs the heat has been a great deal too high. When the oxide is fufed in an martini veffel, it covers the furface with a yellow glafs, as in the coarfeft kinds of pottery. In that cafe fome of the oxide may be diffipated, unlefs the pro- per @N THE OXIDES OF LEAD. 983 per precautions are taken. It deferves attention, that when Singular fa. carbonate of lead is flowly heated in a glafs retort till it begins to melt, the melted portion has a fine yellow colour, while’ the colour of what remains in the ftate of a powder is a dirty pale brick-red; whereas in a platinum crucible the melted portion is red and the unmelted yellow. 5. From the preceding experiments it follows, that the Cotreéted ele~ yellow oxide of lead contains 10.3 per cent. of oxigen. Mr, pepe off che Prouft has deduced nine per cent. as the proportion of oxigen, pve from his experiments. This refult does not differ much from mine. If I have committed an error, the oxigen I think is rated too high; for the lead which I ufed contained 14 per cent. of antimony, the oxides of which have much more oxigen than the yellow oxide of lead. Perhaps we fhall come nearer the truth by taking the mean of the two refults: we may therefore confider the yellow oxide of lead as compofed of 902 lead, 92 oxigen. 6. The preceding experiments enable us to ftate the confti- Comp. parts ni- tuents of nitrate of lead as follows: trate of lead, 1. Nitrate dried on Blotting- | 2. Nitrate dried at 300°. Paper. 66 yellow oxide, 68.5 yellow oxide, 34 acid and water, 31.5 acid and water, os —_—— 100 | 100.0 They give us alfo the precipitated carbonate of lead, dried at 300°, as follows: 86 yellow oxide, 14 acid and water. 100. ‘The native carbonate of lead contains about 16 per cent. of carbonic acid. Precipitated carbonate then either contains lefs acid than native, or it lofes a part at a low heat. It is well known that carbonates, when in cryftals, frequently con- iain more acid than when in the ftate of powders. 7. Yellow oxide of lead is a powder of a lively vellow colour, Charaéters and taftele{s, infoluble in water, but foluble in fixed alkalies a ete = in acids. 284 ON THE OXIDES GCF LEADes acids. The alkaline folutions have a yellow tinge; but the. acids are moft frequently colourlefs, It readily melts when heated, and forms a yellow, femitranfparent, brittle, hard glafs, It does not Iofe oxigen gas when heated. In violent heats a portion of the oxide is‘diffipated. When kept heated in the open air, its furface becomes brick-red. When mixed with metallic lead it runs, according to Prouft, into a green glaze. Yellow oxide by 8, The yellow oxide may be obtained direétly from the nitrate ge bean Su of lead, by expofing that falt toa fufficient heat ; but the lofs . of weight fuftgined is ufually greater than it ought to be. I: fufpe& that this is one reafon why Prouft found fo fmall a proportion of oxigen in yellow oxide. One hundred grains of nitrate of lead (obtained by evaporation) were put into a {mall Wedgewood crucible furnifhed with a lid, and enclofed in a common earthen-ware crucible. They were expofed for half an hour to an intenfe red heat in a wind-furnace. The falt was converted into a very hard, yellow, brittle glafs, nearly opake ; It had fuftained a lofs of 40 per cent. or about fix per cent. more than it ought to have loft. On breaking this glafs to pieces the reafon a this became obvious: It contained a great number of globules of lead reduced to the metallic flate, fome of them of confiderable fize. From this experi- ment we learn, that lead is reducible direétly from the nitrate merely by the appl: cation of heat, without adding any com- buflible matter, _ Suppofed fn fi Oxide, Ashes of lead, When lead is = melted in the open air, it is foon covered aga firt with a dirty coloured powder, formerly called the afhes of yellow oxide and lead. When this powder i is heated fufficiently, it melts into a metallic lead. greenifh yellow glafs, in which globules of lead may be de- te€ted. Mr. Prouft has fhewn, that thefe afhes are a mixture of the yellow oxide of lead with lead in the metallic late. They do not, therefore, conftitute a peculiar oxide. Neither is the white oxide of the French chemifts entitled to a place among the oxides of lead; being in all cafes nothing more than the yellow oxide combined with an acid, ufually the carbonic. Prouft’s oxide But Mr. Prouft, in his olsBiranifiabs on the Connoiffances Chi- oy Les Toa miques of Fourcroy, has mentioned the method of forming an eee oxide of lead containing lefs oxigen than the yellow. When lead ¢ ON THE OXIDES OF LEAD. 285 lead is boiled in a folution of nitrate of lead, the liquid gradually affumes a yellow colour, and, on cooling, depofits cry ftals in fcales. Thefe cryftals, according to Prouft, contain the oxide in queftion: But his conclufions, as far as appears, were. formed from the fingle experiment related. He does not feem to have decompofed the falt, nor to have examined its bafe. 1. When 100 grains of nitrate of lead are diffolved in water, The expertmenty- and boiled in a phial with a cylinder of lead (weighing 642 grains), the metal foon lofes its brilliancy and is covered with a white cruft, while the liquid affumes a yellow colour. The boiling was continued (water being added as faft as it evapo- rated) till the liquid feemed to exert no farther aétion on the lead. The cylinder being then taken out and weighed, was found to have loft 44 grains. From this we learn, that 100 grains of nitrate of Jead diffolved in water, are capable of uniting with 44 grains of lead, or almoft half their weight. The whole, however, was not diffolved. A bluifh-grey pow- der fell to the bottom, and increafed in quantity as the cylinder diminifhed, If thefe 44 grains were oxidized at the expence of the yellow oxide of the nitrate, we fhould bave a new oxide containing much lefs oxigen; and it would be eafy to aflign the proportion of its conftituents; for 100 grains of nitrate contain 66 grains of yellow oxide, compofed of 592 lead and 62 oxigen: Therefore the new oxide contains 593 +- 44 lead and 64 oxigen, or, per cent. 94.3 lead, 5.7 oxigen, 100.0 But it is extremely unlikely that the 44 grains of lead thould receive the whole of the oxigen neceflary to enable them to diffolve from the oxide, while an excefs of nitric acid is pre- fentin the folution. Let us therefore examine the new falt. 2. When the folution cools, it depofits thin fcaly cryftals of Depofition of a light yellow colour: They have the fame {weet aftringent a Desig by tafte as common nitrate, but are lefs foluble in water. If the {mail needles by yellow liquid which remains be farther concentrated, it depo- det 3 pas ol fits, on cooling, {mall needles of a pale yellow colour, not nate by cold unlike fugar of lead. Their tafte is fweet and aftringent ; they water. are not altered by expofure to the air, When thrown into cold water they fall to the bottom, the liquid gradually be- comes - 236 ON THE OXIDES OF LEAD, comes milky, and depofits a white powder. This powder does not difappear, though the folution be heated boiling hots but the liquid acquires the property of diffolving an additional quantity of the falt, without depofiting any more white pow- der. Boiling water diffolves the falt without any fimilar de- pofition. Hence I think we may conclude, that the white powder is owing to the prefence of fome carbonic acid in the cold water, and that our falt in this refpeét refembles acetate of lead. The falt depo- 3. When 30 grains of the falt depofited during the boiling fited in the be of the lead in the nitrate, were cautioufly heated to rednefs, veibeunids they melted into a yellow mafs, which weighed 24.5 grains. an under propor- The lofs of 5.5 grains muft be afcribed to acid and water. fion of acids Hence this falt is compofed of 81.5 oxide, 18,5 acid and water. 100.0 Thefe 24.5 grains of oxide being diffolved in nitric acid, yielded 35 grains of common nitrate of lead (dried at 300°). But 35 grains of nitrate contain 24 grains of yellow oxide, which fcarcely differs from the quantity diffolved. From this experiment it feems to follow, that the falt in queftion contains onty yellow oxide, and that it differs from common nitrate in containing a {maller proportion of acid. But it will be faid, perhaps, that the oxide of the falt abforbed oxigen from the nitric acid during the application of the heat, and was thereby oxidized up to the ftate of yellow oxide. as alo the cryf- 4: Twenty-three grains of the needle-form cryftals were tals do. diffolved in water and decompofed by carbonate of potafh. The carbonate had the common appearance, and, when dried in 300°, weighed 24 grains. But 24 grains of common car- bonate contain about 214 of oxide, and ought therefore, when diflolved in nitric acid, to yield about 312 grains of common nitrate of lead (dried at 300°); and, upon trial, I found this to be the cafe very nearly. The oxide in the needle-form cry ftals then is the yellow ; for there is no apparent courfe from which, in the above experiment, oxigen could be drawn. And. © if this be the cafe with the needles, it muft be fo alfo with the - fcaly cryftals; for the two falts are obvioufly the fame. we Sixty- _ ON THE OXIDES OF LEAD. 287 5. Sixty-three grains of the falt, partly in feales and partly The oxide of in needles, were fufed with carbonate of potafh ina Wedge- ae eke wood crucible. By folution and filtration a fleth-coloured from the yellow. powder was obtained, which was a mixture of oxide of lead and filica. It weighed 53 grains; but a portion which I could not eftimate adhered to the crucible. The filica was obvioufly abraded from that veffel. Thirty grains of this powder di- gefted in nitric acid, left 31 grains of filica; of courfe, 262 were diffolved. The folution yielded 392 grains of nitrate of lead. Now 392 of nitrate contain 27 grains of yellow oxide, or almoft the very quantity diffolved. The oxide obtained by this experiment, then, was the yellow ; of courfe, it coincides exaétly with the preceding ores. Prouft’s falt, then, does not appear to contain a different oxide from common nitrate; but its new properties were owing to the different proportion of its acid. It is completely neutralized, whereas common nitrate contains an excefs of acid, and is, in fat, a fuper-nitrate. But if this conclufion be well founded, Prouft’s nitrate may be formed by expofing common nitrate to a heat fufficient to expel the excefs of ee acid. It was requifite to verify this prefumption by experi- ment. 6. One hundred grains of nitrate of lead (dried in 300°) Proug’s fats were expofed to a graduated heat ina flafk. Fumes of nitrous Aig ie yes acid feparated in abundance, and the falt loft five per cent. aed of pom of its weight. On increafing the temperature the falt melted lead. into a tranfparent glafs of a very pale yellow colour, The * weight of the mafs was now reduced to 85 grains. Hence it was compofed of 68,5 oxide and 16.5 acid, or, per cent, of . 80 oxide, . 20 acid, 100. On pouring water into the flafk and digefting, I obtained a yellow folution fimilar to that formed by boiling lead in nitrate of lead, but not fo deep. A yellow powder refufed to dif- folve; it confifted chiefly of the portion of falt at the bottom of the flafk, which had been expofed to a higher temperature. It was taftelefs, and not unlike fub-muriate of lead. When heated to rednefs it melted into a yellow glafs, and loft 14 per «ent. It was therefore compofed of 2 ; 86 988 ON THE OXIDES OF LEAD, 86 oxide, t& acid and water. 100. The folution being evaporated, depofited two fets of eryf- tals; one fet confifting of common nitrate of lead, another fet refembling thofe obtained by Prouft. Three nitratesof 7, From the preceding details we learn, that there are three a Ha ag diftinét fpecies‘of nitrated lead: The firft is a fuper-nitrate, or aenels or with contains an excels of acid; the fecond is neutral; the third defect of acide Contains an excefs of bafe, and is, of courfe, a fub-nitrate. The firf,[pecies includes the common nitrate of chemifts in all its varieties; the fecond, the nitrate of Pronft; the third, the yellow powder ebtained by heating common nitrate fufh- ciently. Ili. Brown Oxide. Brown oxide 5 Though this oxide contains a maximaim of oxigen, I beg ieft when mini- leave to introduce it Here, becaufe the knowledge of its eom~ heat he pofition is neceffary to enable us to analyfe the red oxide of lead. Xe It was difcovered by Scheele, and deferibed by him in his differtation on manganefe. When diluted nitric acid is poured upon red lead, the greater part of the oxide is diffolved, but a brown powder remains behind, which is not aéted upon by the acid. This brown powder is the brown oxide of lead. Prouft difcovered that it may be formed alfo by caufing a curs rent of oxi-muriatic acid gas to pafs through red lead fufs pended in water. Its habitudes ; 1. This oxide is a taftelefs powder, of a flea-brown colour, and very fine and light. It is not aéted on by fulphuric nor nitric acid. To muriatic it gives out oxigen, and converts it into oxi-muriatic acid. Oxi-muriatic acid diffolves it, and forms two falts, muriate and hyper-oxi-muriate of lead... The vegetable acids reduce it to the ftate of yellow oxide, Four- croy, on the authority of Vauquelin, affirms, that fulphur takes fire when triturated with brown oxide of lead. With me the experiment did not fucceed: I fufpeét, therefore, that the oxide ufed by Vauquelin contained a portion of hyperonix muriate of lead mixed with it. contains one- 2. When 100 grains of this oxide, prepared from red lead tenth more oxi-, by nitric acid, are expofed to a red heat, they lofe nine grains gen than yellow # f o. 3 ON THE OXIDES OF LEAD. 289 of their weight, and are converted into yellow oxide: Thefe oxide; eafily nine grains are oxigen gas. Herice brown oxide is compofed ‘!8*8°4- of 91 yellow axide and 9 oxigen. But 91 of yellow oxide contain 9,4 of oxigen. Therefore 100 parts of brown oxide are compofed of 81.6 lead, 18.4 oxigen, 2 100. 3. Mr, Prouft, from his experiments, ftates the proportion of oxigen in this oxide at 21 per cent. If we take the mean of the two refulis, we obtain 19.7. We may, therefore, lay . down 20 per cent. as the proportion of oxigen in brown oxide of lead: This cannot deviate far from the truth. IV. Red Oxide. Red lead being one of the moft common of pigment, is un-Red lead ; known, I prefume, to no perfon. The method of manufac- turing it has been defcribed by Dr. Watfon in his Chemical Effays, by Jars in the Memoires of the French Academy for 1770, and-by Ferber in his Mineralogy of Derbythire. 1. It isa taftelefs powder, very heavy, and of an intenfe its chiraéters ; red colour, often inclining to orange. I have never met with _ any fpecimens of it abfolutely pure, but not unfrequently the foreign bodies do not exceed one or two per cent. They confift of feven grains of fand and oxide of antimony. Dr. Watfon found traces of filver in it. It lofes no fenfible weight - ~ ina heat of 400°. 2, When 50 grains of red lead are digefted in diluted nitric contains 88 lead acid, they leave 12 grains of brown oxide, The folution eva- bh AACR s2 porated to drynefs, yields 56 grains of nitrate of lead. Now, 56 grains of nitrate contain 38.36 grains of yellow oxide. Red lead, therefore, is compofed of 38.36 yellow oxide and 12 brown oxide, or, per cent. of 76.72 yellow oxide, 24,00 brown oxide. 100 72 The excefs muft be afcribed to the imperfection of our me- thods. I fhall omit it in the calculation: Not that red lead Vou, VIII.—Avucusr, 1804. U is 390 ON THE OXIDES OF LEAD. is a mixture of yellow and brown oxides, but that it contains all the lead and oxigen in the above proportions of thefe bodies. Now 76 grains yellow oxide is compofed of 63.8-++ 7.2 24 grains brown oxide of - - - 19.24 4.8 aes Therefore red lead is compofed of - 88. +12. =100. not eafily de- 3. It is well known that red lead gives out oxigen gas when ren The reverfe of this fa& alfo occurred to me in the courfe If carbonic acid of a feries of experiments, to which I have already referred; be mixed with 5 x é ‘ i another gas, the viz, that the admixture of common air with carbonic acid gas abforption by diminifhes confiderably the proportion of the latter gas taken aa haga y? up by water. Thus, when 20 meafures of pure carbonic acid fity M4 na rn as are agitated with 10 of water, at !eaft 10 meafures of gas bonis ie and are abforbed. But from a mixture of 20 meafures of carbonic na Oe rt acid with 10 of common air, 10 parts of water take only 6 of carbonic acid. That chemical affinity between the mixed gafes is not the caufe of the diminifhed amount of abforption, is perfectly clear; fince it is indifferent, as to the effe€t, what gas is added, and the proportion alone influences the refult. The effect is therefore to be afcribed to the diminifhed denfity of the fuperincumbent carbonic acid by mixture with another gas; and the preffure of gafes being direét!y as their denfity, and the quantity abforbed by water being as-the preffure, the abforbed carbonic acid muft neceffarily quit the water. This - efcape continues till the carbonic acid above the water has a denfity equa! to that zn the water, and no longer. Previoufly to my acquiefcence in your theory of mixed ae has 7 gafes, I undertook an extenfive feries of experiments, with a F aaten daa ip view to a(fcertain the order of affinities of gafes for water, the gafes, But, after a great variety of trials, made wiih all the accuracy jn my power, I could difcover nothing like a feries of eleéctive attraGtions. Each gas, it was found, difplaced every other, and reciprocally was diflodged by them. *' Tt may be urged againft the doétrine of the non-gravitation The flower é ’ . -,, efcape of a gas of gafes on each other, that from water impregnated with ¢. or ater ex- carbonic acid gas, and expofed to the atmofphere, the gas pofed to the at- ought, on this principle, to efcape as rapidly as under an ex- ewe haufted receiver. It muft be remembered, however, that the vacuum arifes efcaping gas conftilutes, by admixture with the*air of the at en patter sad mofphere, a gas of diminithed denfity, but fill of {uch denfity of the fuperin- as to retard the efcape of farther portions. All that the air- cumbent gas. pump effeéis is to remove thefe as falt as they are liberated. There are various faéts, fatisfactorily explained on this doc. Faéts explained trine, which are irreconcilable to any former hypothefis. Of “betaggs : TO Lh ae a thefle £00 CONSTITUTION OF MIXED GASES. > thefe I thall mention only a few; fince the theory will receive from yourfelf all the elucidation that its eftablifhment can re- quire. awn Dy 2 Light and heavy 1. If each gas be a vacuum to every other, a heavier gas re fon= Mould afcend into a lighter one, without the aid of agitation ; and on the contrary a lighter one fhould defcend into a heavier one. That this is adtually the faét, and under cireumftances very unfavourable to their mixture, your own experiments have fully proved. Sulphuret takes 2. The hypothefis explains why fulphuret of potafh with- peat draws oxygen from the air without agitation, and whether placed at the top or at the bottom of a jar; for it aéts as if the abforbed gas were the only one prefent in the veffel. Abforbable gafes 3. It explains why the lafp portions of common air are ex- Sitch ee pelled from water by carbonic acid, and other abforbable gafes. mon air from For thefe gafes act as a vacuum to the air contained in the Myr l water, which muft therefore neceffarily quit its place. It folves alfo the problem how to expel completely any gas from water; for to effect this, the water muft fucceffively be agi- tated with portions of fome other gas of the greateft attainable purity. Thus to expel atmofpherical air entirely from water, it may be agitated with pure carbonic acid gas; but as the li- berated common air preffes on that remaining in the water, according to the proportion it bears to the fuperincumbent car- bonic acid, the gas thus employed muft be removed, and frefh and pure portions ufed in fucceffion. Beft method of | 4. By applying the fame general law, we are taught how to impregnating eff the higheft attainable impregnation of water with any water witha gas. ; ; ad . t gas. There could be no difficulty in accomplifhing this objeét, if the gas and water were both abfolutely uncontaminated by admixture with other gafes; but when pure carbonic acid is agitated with water, atmofphefcal air 1s extricated, which, mingling with the carbonic acid, leffens its denfity. To ob- viate this difficulty as much as poffible, a quantity of water, to be impregnated fully with carbonic acid, fhould be agitated with feveral fucceflive portions of the pureft poffible gas. The unabforbed refiduum fhould alfo be very large, in order that the carbonic acid may bear a large proportion to other aeriform fubftances accidentally mixed with it. Thefe are, doubtlefs, only a few of the phenomena, to the explanation of which your theory may be fuccefsfully applied; and gee ee aa ae DISAPPEARANCE OF OXIGEN AND HIDROGEN, S01 and I confidently expeét that many facts, hitherto referred to chemical principles, will be brought, in confequence of your difcoveries, within the pale of mechanical philofophy.* Iam, Dear Sir, Your’s very truly, ithe WILLIAM HENRY. Manchefter, June 20, 1804. , XIII. On the Difuppearance of Oxigen and Hidrogen over Water, at the Heat of the Atmofphere. By T.S. T, ) To Mr. NICHOLSON. Sik, - Some months ago, Tread in your excellent Journal an ac- Slow abforptioa count of an experiment, which tended to thew that oxyge- “ly st and nous and hydrogenous gafes, when mixed together, and al- Pais chad lowed to remain over the furface of water for along time, fpontaneouily united and formed water. “. Having long been accuftomed to confider a temperature confiderably higher than that our atmofphere ever attains, ne- ceflary to this union, I was naturally led to inveftigate this phenomenon; and for that purpofe undertook the following experiments : 1. I prepared oxygen gas from black oxide of manganefe, by means of concentrated fulphuric acid, aided by heat, and in order to render it more pure, I wafhed it well with milk of lime. I prepared likewife a quantity of hydrogen gas, by pafling a few drops of water through a gun-barrel, filled with ‘iron filings, and paffed through the body of a fmall furnace, I introduced nearly equal quantities for both gafes into a bell- glafs jar, placed on the thelf of a common pneumatic trough, which ftood in a room without fire, and almoft without light. The mixture was fuffered to remain in that fituation for about five months; at the end of which time, the volume of the gafes had diminifhed . * As the author had not feen Mr. Dalton’s letter, publifhed in our laft number, at the time when thefe illuftrations were written, he has mentioned a few circumftances contained in the letter, 2,On 302 Slow abforption of oxigen and hidrogen over ‘qwatere DISAPPEARANCE OF OXIGEN AND HIDROGEN, 2. On reading the account above alluded to, it occurred to me that it was poffible, that the diminution in bulk, might have _arifen from a partial abforption of one or of both gafes, by the water of the trough. In order to afcertain this, I introduced like proportions of both gafes, into a jar, placed in a mercu- rial trough, which was in thé fame room with the other; and after fuffering this experiment to continue as long as the other, { found that of 12 cubic inches of both gafes introduced into the jar, 32 had difappeared; but I could fcarcely perceive any moifture on the fides of the jar, owing to the fmall quan- tity of water which had been formed. | The decreafe in volume, in thefe experiments, could not be owing to any condenfation of the gafes, by the coolnefs of the furrounding air; for I found that it took place gradually ; and the mixtures were made in the beginning of January, and flood till the end of May; confequently there fhould have been rather: an increafe than a decreafe in bulk, if the tems perature of the air was the caufe. The refiduary air contained in the jars, ftill confifted of ox- ygen and hydrogen gafes; for when received into a phial, on the application of a lighted taper, a {mart explofion took place, and the fides of the phial grew dim. On adding fulphuret of lime to another portion of the refidue, a rapid abforption of the oxygen gas took place, and hydrogenous gas was left bes hind. ; From thefe faéts we may fairly conclude, that the decreafe in volume was owing to the fpontaneous combination of the two gafes to form water.* Eee ae igh Orkney, June 20th, 1804. : \ * It deferves to be confidered whether the abforption of the purer gafes within, and the efcape at the furface of the water ex~ pofed to the atmofphere, according to the doétrine explained in Mr. Henry’s paper (page 297 ) may not have occafioned the deficiency. W.N. Detter -ON THE DEATH OF MR. HUMBOLDT, 803 XIV. Letter from Dr. P. A. Nemnic H, exprefing Doubts with regard to the Death of the celebrated Humboldt. To Mr. NICHOLSON. SIR, Hamburgh, June 29, 1804. Your Journal of Natural Philofophy, &c. June 1, 1804, Inquiry sgt page 72, mentions pofitively the death of Mr. Humboldt, pare on which, as we had here in Germany no other advices, I imme- Humboldt. diately communicated to my countrymen through the channel of our newfpapers. There are however in Germany, as well asin France, many doubts about the validity of the faid notice, and many objections made. Having quoted your Journal, as above-mentioned, I fhould be very much obliged to you fora more circumftantial and pofitive account of this report of Mr. Humboldt’s death, with the day of his deceafe, and the way by which this notice reached England, 8c. which as foon as I have received, I will inftantly make public, in order to main- tain that credibility your valuable Journal deferves. Iam, Sir, Your’s moft refpeétfully, P. A. NEMNICH, Licentiate, ( Extrait du Publicifte. Paris, 20 Juin, 1804. VOTRE feuille de ce jour contient a l’article de Hambourg Extraét from the la nouvelle de la mort le Mr. de Humboldt. II m’eft permis nine d’en révoquer en doute l’authenticité, et de raffurer les amis des fciences et de ’humanité. Je fais pofitivement que Mr. Guil. de Humboldt 4 Rome, a regu de fon frere des lettres _datées de la Havane du 28 Mars, dans lefquelles il lui mar- quoit que fous 12 jours il feroit rendu a Charleftown d’ou il s’embarqueroit de fuite pour le Havre, et qu’il comptait étre -& Paris avant la fin de fuin,—La nouvelle eft donc plus que douteufe et nous pouvons efperer, que le fort ne fe feroit pas fait un jeu cruel de rendre vain le dévouement fans bornes et les nobles efforts de I’ illuftre voyageur. (Signé) Mendelffohn, 3 Extra BOA Tranflation. ON THE DEATH OF MR. HUMBOLDT. Extra from the Publicifte. Paris, 20th June, 1804. YOUR number of this day contains under the article Ham- burgh, an account of the death of Mr. de Humboldt. Ihave reafons to doubt the authenticity of this article, and to en- courag¢ the friends of fcience and of humanity. I know po- fitively that Mr. William de Humboldt received from his bro- ther letters dated from thé Havannah, of the 28th March, in which he informs him that in twelve days he fhould go to Charieftown and embark for Havre, with the expe@tation of arriving in Paris before the end of June. Your article of news is therefore more than doubtful, and we may hope that the courfe of events have not been fo unfavourable as to render the unlimited facrifices and efforts of this illuftrious traveller of no ufe to fociety. 5 on foe: Gibbes, the author of the note in queftion, will, no doubt, have the goodnefs to mention his authority, when he fees this. W.N, ——= a i> From the extraordinary Number of valuable Communications this Month, (every one of the Articles, but thofe of Gay Lussac and Baxvuoxnpt, being original) it has been nece/- fary to pofipone an excellent Memoir on Hauy’s Syjtem, by the Abbé Briel, and a Paper by E.O.on the Computation of Tables of Squares and Cubes, both which, and fome Abridgements and ColleAions of interefing Matter from the Plal. Tranfaétions, together with the Scicntific News, will appear in our neat. Philos, Journal. Vou. Vil. Pu. XML p.304. ; = a, PP oy Lanting Con fedsed. Wo Ulf. q , N * . N : N : : WN . NN ; be re ) 4 ‘ 2 } Mullow Se Rujsal Cot Lhilos. Journal Vo VI PLAIN. p. 30g : : ee My “sl Z x Ci $ j | Sryproved Dhenee rs Lampe e | PUVOV UV UD POUT UD oDU FUN OONUTT TYTN UU ceWoEVENT ATF eae = = = Engraved éy Mutlo INDEX. A. Accum, Mr. his examination of a fone containing potafh, 127—«His pro- cefs for obtaining alumine pure, 260 —Defcription of his. improved chemical lamp with double concentric wicks, 266 Acid, nitrous, accenfion of fulphuretted hidrogen gas by, 144 —— phofphoric, abundant in vegetables, 241 fuberic, contained in paper, 142 Acids, neutralization of, by the metallic oxides, 273 Affinity, chemical, of common air, ex- amined, 145—Of the gafes for each other, is alike in all, 148 Air, on the change which it undergoes by refpiration, 40—On the fuppofed che- mical affinity of its elements, 145—Its denfity is the caufe of the various phe- nomena of combuftion, 146—Is not diffolved by water, 149—Poffeffes hy- girometrical attraction, 245—Reafons for confidering it an homogeneous fluid, ib. Alchemy, on the refearches which con- ftitute the fubje&ts of, 27 Alcohol, its mutual repulfive aétion with other fluids, 2ox Alumine, on the difficulty of obtaining it in-a ftate of purity, 141—A method pointed out, 260—Is precipitated by the metallic oxides, 274, Amber, large fpecimen of, 143 Ammonia, its repulfive action on other fluids, 204—Diffolves oxide of iron at a minimum, 272 Vor. VIF. Animal body, effeéts of galvanifm on the, 179 Apparatus, for filtering water, defcription of an, 126 galvanic, on the means of fim- plifying and improving, 1—In a fingle piece, 3—Affording a larger furface for ’ oxidation, and convertible into one or more plates, 79 Arch of the meridian meafured in the Myfore,: 18 Arnold, Mr. 47 Arfeniated copper, Hauy’s obfervations omy 187—Varieties of, 188—Anal) fes of, 189—Count de Bournon’s ieply, 247 Afh, Dr. 72 Afhes of lead, compofition of, 284 Atmofphere, comparifon of its tempera ture with fea water, 132 : Attraction hygrometrical, is diminifhed by the accefflion of water, 244 Azote, eleétricity does not fufe lead placed in, 82 |B. Banks, Sir Jof. 221—His report of the ftate of his Majefty’s flock of fine- wooled Spanifh fheep, 277 Bartholdi, Prof. on fpontaneous inflam- mations, 216, 236 Barton, Dr. on the fafcinating faculty af cribed to the rattle«(nake and other American ferpents, 53, 100 Beaupoil, on the viitues and principles of cantharides, 76 Bedford, Duke of, 279 Bergman, 272; 280 Bertholiet on the differences between heat and electricity, 80—His obfervations ua _) Coung INDEX. Count Rumford’s doétrine refpecting fluids as non-conduétors of caloric, 134, 198, 274 Berthollet the younger, 273 Black,. 76 Blacquiere, Col. 23. Bleaching of wool, experiments and obfer- vations on, 96 Blumenbach, Prof. ro2 Boiler of ftone, fact refpeéting water heat- edina, 1269 Boiling oily matters, fpontaneous inflam- mation from, 2.39 Bones of animals, contain a phofphate not found in thofe of men, 85—Method of feparating magnefia from, 86 Books, account of new, 222 Bournon, count de, 187—His reply to the Abbé Hauy’s obfervations on arfeniated Copper, 247 Bramah, Mri I. defcription of his jib on a new conftrudtion, 99 Bramley, R. R. Efq. on the dvy rot in timber, 8 Brown precipitate from platina, 120 | Brugnatelli, 142—His new method of pre- paring nitric ether, 143 Bruhl, Count de, 47 Bucket, gaining and lofing of an early date, 37 . Burg, 160 Cc. Caloricy a compound of plus and minus electricity, 71—-On its nature as de- duced from galvanic experiments, 88 Cantharides, on the virtues and principles of, 76 Carbomate of lead, analyfis of 282——Sin- gular faét in its fufion, 283 Carlifle, A. Efg. 71—-On the temperature of the fea, 131 Cartwright, Rev. E. defcription.and draw- ing of his three furrow plough, 24. Cafanova, 235 Caylus, Count, 233 Chain-pump, of an early date, 37. Chappe, 164 Charaéters, exterior, the only means of feparatieg the mineralogical fpecies, 252 Charcoal, durability of, 8—Emits an in- tenfe light in galvanic combuftion, 73 — Spontaneous inflammation of, in a powder magazine, 241—Contains phof- phorus, 242 Charles, Cit. 80 Mr. D. account of his machine for laying land level, 181 Charring prevents the dry rot in timber, Chenevix, Mr. his analyfes of arfeniated copper, 188—248 Chronometers, caufes of irregularities in, 46—Great accuracy of the mean refult from a number of, 65—Tables of the going of three, 68 Cleanfing of wool, experiments and ob- fervations on, 94 ; Clock, new ftriking part for a, 162 Cobalt, fuperior hygrometric properties of its oxide, $5 ; Cock, Mr. 20 » Coke, Mr. 279 Cole’s chain pump, 37 Collet-Defcotils on the caufe of the differ-~ ent colours of the tripie falts of platina, and on a new metallic fubftance in that metal, 118, 220 Coloured glafs, antique, 227 Combuftibles, abforb different quantities of oxigen from common air, 146 Combuttion, its intenfity depends on the ftate of the oxigen, 147 Compreffion of the earth, mean, 159 Copal varnifh, eafy method of preparing, 142 Copper, unneceffary in a galvanic appara~- tus, 1-Obfervations on the arfeniated, 187, 247-——Yields different coloured enamels according to its ftate of oxida- tion, 229——-Mutual precipitations with iron, 271 Councer, INDEX. Councer, Mr, mathematical tables con- ftructed by, 62 Courfe of a body projected from the moon to the earth, method of inveftigating, 22 Crawford, 76 Cronftedt, 207 Cruickfhank, Mr. 4 Cubes, a very extenfive table of, 62—= Eafy method of completing them, 150 Cumming, Mr. 47 _ Cuthbertfon, Mr, ona diftinguifhing pro- perty between the galvanic and ele¢tric fluids, 97—Refpecting galvanic and eleGtrical experiments, 205 D. Dalby, Mr. 18, 156 Dalton, Mr. on the fuppofed chemical affinity of common air, 14.5—Illuftra- -tions of his theory of mixed gafes, 297 Davy, Prof. 42, 147 Decompofition of water, known to the ancients, 23 Deflagrations, galvanic, 97 De la*Cépéde, 59, 101 Delambre, 13 Delametherie, 213 D’Elhuyar, 207 De Marti, 43 Demmenie, 142 Denon’s account of an ancient Egyptian lock, 115 Denfity of the air influences combuttion, 147 Defagulier’s gaining and lofing bucket, 37 Deyeux, 76 Dieman, 82 Dilatation produced by eleétricity, 81 Difke of difperfion, 202 Draparnaud on the movement which cer- tain fluids receive from: the contaét of other fluids, 201 Dry rot in Timber, obfervations and com- munications on, § gs Duckitt, 182 * Du Hamel, 224 Du Sejour, 43 Dyckhoff, 2 “ E. Earth, the, on its figure, 12—-On the courfe and velocity of badies projected from the moon to, 22——Is probably an ellipfoid, 159 ——-- a new one, chemical examination of, 209 Eccentricity of a place of obfervation, me- thod of determining, 156 Edridge, Mr. 273 Eeles, 71 ' Eleétricity, the pofitive and negative are not proved to be diftinét principles, 71 —Differences between it and heat, 80—« Aéts by dilating bodies, 81—Favours oxidation by diminifhing the cohefion, $2—-Method of comparing it with gal- vanifm, 176—Comparifon of its phe~ nomena with magnetifm, 184—-New experiment in proof of its identity with galvanifm, 212 Ellipfoid, the figure of the earth is probably ally 159 Emery, Mr. 49. Enamels of the ancients, memoir on the, 225—Very curious and antique one of a duck, 234—Extremely minute one of a bird, 235 Engines, old, re-invented, 37 E. P. on the ftate of fcience among the ancients, and on alchemical refearchesy 27 Ether, fluoric, procefs for obtaining, 143 -——- nitric, new methodseof preparing, 143 Eton’s account of an ancient Egyptian lock, 116 Eudiometers, comparative examination of different, 41 Euler, 13 Expanfion of liquids correfponds with the fquare of their temperatures, 149 Experiments, galvanic, by Ritter, 176—-— Van Marum’s obfervations on, 212 b2 Fabroniy ' INDEX. F. Fabroni, 83 Fafcinating faculty afcribed to the rattle- fnake and other American ferpents, me- " mgiron §8—100 Ferber, 230, 289 Fergufon, Dr. A, 164 Fermentation, fpontaneous inflammation from, 236 Fire, generation of, 90 Fluid, ele€tric is not neceffary to the for- mation of fhow, 76—-Curious and im- portant property which diftinguifhes it from the galvanic, 97 Fluids, examination of Count Rumford’s do@rine of the non-conduéting proper-~ ties of, 134—-Are proper conduétors of : heat, 137, 198--Experiments on the currents in, 139—Their expanfion cor- ~ refponds with the fquare of their’ tem- “perature, 149—Differ in the power of conducting heat, 198—On the move- ments produced in them by the contaét of other fluids, 201 Gue——— elattic, the effects of their fpecific gravity examined, 147 Fourcroy, on a new earthy phofpate found in the bones of animals, but not in thofe of men, $5—-142 Friétion, {pontaneous inflammation from, 218 Fuel, attempt to reduce its confumption in fteam-engines, 169 Furnace, ufe of the lamp, 268 - G. G. A. on the formation of fnow, 73 Galvanifm, cannot charge a Leyden Jar, 3—Outlines of Dr. Gibbes’s theory of, 70=—Difengages an intenfe light from charcoal, 72—~The great energy of its chemical effeéts may arife from its con- ftancy, 83—Two very marked laws in, 84-—Makes filver remarkably brittle, 85 =-Facts and obfervations tending to elu- cidate the theory of, 171—-Method of comparing it with ele¢tricity, 176— Hidrogenates and oxigenates meta's in the dry way, 178—Its effeéts on the animal body, 179—New experiment in proof of its identity with cleétricity, 212 Gas, ammoniacal, decompofition of by electricity, 82 ——- nitric acid, fpontaneous inflammation of paper in, 98 —- nitrous, objections to its ufe in eudio- metrical examinations, 4.1 ——- phofphorated hidrogen, fpontaneous inflammation of, 239 —- refembling common air, obtained in preparing nitrous acid, 147 —- fulphuretted hidrogen, accenfionof, by nitrous acid, 144—Spontaneous inflam- mation of, 239 Gafes, have all the fame affinity for each other, 148—Receive heat very rapidly, 198—lIlluftrations of Mr. Dalton’s the- ory of mixed, 297 Gay-Luffac, 80—-On the mutual pre- cipitations of metallic oxides, 270 Gibbes, Dr. outlines of his theory df gal- vanilm, 70—304. Gillet Laumont, 187 Glafs, hiftory of the invention of, 225— Antiquity of the art of colouring, 226 —Roman mofaic work of, 227—Me- thod of painting in, prattifed by the ancientsyi2 93/7 Gmelin, 230—291 Gough, Mr. J. on the folution of water in the atmofphere, and on the nature of atmofpheric airy 243 Gravity, fpecific, of elaftic fluids, effeéts of, 147 . Greafy animal and vegetable matters, {pon taneous inflammation from, 237 Green, Mr. R..defcription and drawing of his hand-drill, 19 Guaiacum, experiments on the aétion of light on, 294 Guyton, 42 Haley, INDEX. H. Haley, Mr. on the caufes of irregularities in chronometers, 46 Hand-drill, defcription and drawing of a very economical, 19 Hardy, Lieut. Col. 181 Harman and Dearn, Meff. their apparatus for filtering water, 333 Harrifon, Mr. 47 Haufiman, 237 Hauy’s obfervations on arfeniated copper, 187—Count de Bournon’s reply to, 247— Hay, utility of adding falt to, 237 Heat, differences between it and eleétricity, 80—Compound nature of, 9o—Paffes through the particles of fluids, 198— That from incombuftible bodies occa- fions {pontaneous inflammation, 220— Difference in the radiation of folar and culinary, 297 Henckel, 232 Henderfon, Dr. on the change of air by refpiration, particularly with regard to the abforption of nitrogen, 40 Henry, Mr. W. 149—On Mr Dalton’s theory of mixed gafes, 297 Herfchell, Dr. 72, 214 H. G. his method of completing the tables of fquares and cubes, 150 Hidrate of copper, arfeniates of, 191 Hidrogen, a compound of water and minus ele&tricity, 71—On its nature as de- duced from galvanic experiments, 38—_ Difappearance of a mixture of it and oxigen over water, 301 Hidrogenation of metals has different de- grees, 178 ° Hippocrates, 77 Hoffman, 74 ‘Hope, Dr. 42 Horace, 108 Hornblower, Mr. I. C. account of a fact refpyecting water heated in a boiler of ftone, 169 Horfe-mill of an early date, 37 3 Howard, Mr. 22 Human figure, defcription and ufe of a te- legraph formed by the, 164—Mecha- nical additions to, 167 Humboldt, 42—Notice of his death, 72 —Queftion refpecting it, 303 Hulton, Dr, 63 Hydraulic machine of an early date, des fcription and drawing of, 35 Hygrometer of oxide of cobalt, propofed, 85 I. Jager, 185 Jars, 289 Jib, defcription and drawing of one ona new conftruétion, 99 Inflammations, fpontaneous, caufes of, 217 Inventions of an early date which have been fince brought forward by later inven tors, 35 Johnfon, B. Efq. obfervations and com- munications refpecting the dry rot in timber, 5 Jones, Mr. W. his examination of Dr. Wollafton’s experiment on perifcopic {petacles, 38 I. R. I. ona galvanic apparatus of large furface, and convertible into one or more plates, 79—-On fome facts in galvanifmy and on other objects, 84 Iridium, a new metal found in platina, 221 Jron, can yield a blue enamel, 282—The bad quality of the cold-fhort, probably caufed by the charcoal, 242—Mutual precipitation with copper, 271% Irwine, 76 K. Kalm, 62, 101 Kaftner, 236 Klaproth, 127, 142, 187—His analyfee of arfeniated copper, 196—Chemical examination of the ochroites, 207—On the pattes, coloured gloffes, or enamels of the ancients, 225, -47 Klein, J. T. 134 Lakanal, INDEX. L. Lakanal, 164 Lalande, Jerome de, on the figure of the orbits of the new planets, 222 Lambton, Brig. Maj. 18 Lamp, defcription and drawing of an im- proved chemical, with dauble concentric wicks, 266 . La Peroufe, 66 La Place, 22, 160 Lavoifier, 172 Lead, placed in azote gas is not fufed by ele€tricity, 82—-Memoir on the oxides of, 280 Legendre, 13, 152 Lelievre, 187 Levelling of land, defcription of a machine for, 181 Light, intenfe, difengaged from charcoal by galvanifm, 73—Experiments on, 214--On certain chemical effects of,293 Linnzus, 107, 131 Litharge, analy fis of, 291 Lock, account of an Egyptian one of great antiquity, 11§5—-Imp:ovement by which it is rendered fafe, 117 Longitude, on the methods of finding it at fea, 65 M. Machine for clearing roads from mud, 29 - early hydraulic, 35 - for levelling Jand, 181 Magnefia, method of feparating it from the hones of animals, 36—-P recipitates earths and oxides from their folutions, 274 Magnetifm, experiments on, 134 Maitland, J. Efq. 277 .Mafkelyne, Dr. 48, 160 Mafon, 160 Maffey, Mr. E, defcription of his new ftriking part for a clock, 162 Mather, Cotton, 107 | Matlack, T. Efq. 111 Mawe, Mr. 259 _ Mayer, 160, 236 Mercury is a better conducter of heat than water, 138 Meridian, meafure of an arch of, in the | Myfore, 18 r Merlin’s gouty chair, 37 Metallic fubftance, on the exiftence of a new one in platina, ‘118-——-Chemical ex- amination of it, 125 , Metals, antiquity of a belief in.the tranf- mutation of, 28-—Eftects of electricity on, 32—Their hidrogenation has differ ent degrees, 178—Their oxidation in water produces an acid, 185—Two new ones, 220 Meyer; 164 Mineral which contains a new eae 207 Meon, on the courfe and velocity of 4 ~ body projeéted to the earth from, 22——~ Inequalities i in her motion, 160 % Motrozzo, 146 =f Mortar, its effeéts‘on timber, 12 Mofaic work of glafs, Roman, 227, Moxon, 36 Mudge’s remontoire, 48 Muller, 6 Mauriates, triple of platina, experiments ‘on the, 121 Murray, 140, 169, 198 Muffin-Pufchkin, 122 N. Nairne, 8 Natrum of the anc! tents, 226 Neimnich, Dr. P. A. letter from him re- {pecting Humboldt’s death, 303 Newton, Sir I. 12, 160, 234 Nicholfon, 71, 131, 198 Nitiate of lead, component parts of, 283 —Three varieties of, 238 Nitrogen, on its abforption in refpiration, 40 | MCS itt Nomenclature for metallic oxides, pro- pofed, 292 3 O. Oak-timber, caufes of its decay, 7 Obfervation, method of determining the eccentricity of the place of, 156 Ochrovs ‘INDEX. @chroit earth, noti¢e of, 142—Chemical éxamination of, 207 Odorant bodies, emanatiuns of, 201 Oil, is a worfe conduétor of heat, than mercury, 139—Mutual repulfion with alcohol, 203 — effential, repulfive action of, 203 Optic nerve, effeét of the galvanic influ- ence on the, 215 Orbits of thé new planets, 222 Orfted, Mr. 176, 184, 212, 214 Ofmium, a new metal found in platina, 221 Oxidation, requires a difengagement of ele€tricity, 72—-Of metals in pure wa- ter, produces an acid, 185—lIts influ- ence on metallic precipitations, 274 Oxide of cobalt, fuperior hygrometric pro- perties of, 35 Oxides, metallic, on the mutual precipi- tations of, 170—Neutralization of the acids by, 273—Great importance of the analyfis of, 280—Propofed nomencla- ture for, 292 Oxigen, a compound of water and plws eleétricity, 71—On its nature as de- duced from galvanic experiments, 88— Difappearance of a mixture of it and hidrogen over water, 30% P. Painting on glafs, method-of, practifed by the ancients, 233 Paintings, invention to multiply copies of, 236 Palcani, Dr. 218 Paper, fpontaneous inflammation of, in nitric acid gas, 98—Yields fuberic acid, - 142 -Parry, Dr. 279 Paftes of the ancients, memoir on the, 225—Refemble ous enamels, 233 Paum, 226 Pearfon, Dr. communication from him refpecting a diftinguifhing property of the galvanicand electric Quids, g8—205 ————————————— SE Pendulum for regulating the ftriking part of aclock, 162 Pennant, Mr. 105: Perifcopic fpe&tacles, examination of the, 33 Perrins, Mr. his table of the temperature of the fea compared with the atmofphere 132, Pfaff, 177 Phofphate of magnefia is found in the bones of animals but not in thofe of men, $5 Phofpheric riags accounted for, 64 Phofphorus in charcoal may caufe detona- tions, 242 Piclet, 138, 198 Pile of difhes, recommended for galvanic experiments, 2, 4 Pipe, ready method of eftimating the con+ tents of, 64 Piper, Mr.'20 Pifo, 107 Planets, orbits of the new, 222 Plant which occafions the dry rot, § Platina, ation of ele€tricity on, S$o+-Caufe of the difference of colour in the triple falts of, 118--Foreign admixtures in,ib. —Blue fublimate obtained by diftilling, 119—Chemical examinetion of a me- tallic fubftance peculiar to, 125—Two new metals difcovered in, 220 Playfair, Prof. obfervations on his mea mgir on the figure of the earth, 12, 156 Pliny, 225 Plough, defcription and drawing of a three~ furrow, Z4 Potath, examination of a {one containing, 126 P. Q. on an ancient Egyptian Lock, x15 Precipitates, metallic, are not pure ox- ides, 273 Prevoft, 204 Prieftley, De» 72) 147 Problem for finding the figure of the earth, folution of, 13—I[n {phercidal triangles, new, 451 Proteus, INDEX. Proteus, Peregrinus, on the figure of the earth, 12—New problems in fpheroidal triangles, 151 Prouft, 273-—His analyfes of metallic ox- ides, 281 Pyrophorus, caufe of its fpontaneous in- flammation, 240 R. Rattle-fnake, on the fafcinatinig faculty af- cribed to the, §8 Rays, invifible, which aét chemically, 214—May be feparated from the colour- ed, 216 R. B. on early inventions, 35—On phof- phoric rings, 64 Red-lead, analyfis of, 289 Red precipitate obtained from platina, 120 Remontoire, various opinions refpecting the, 47 Repulfion, mutual, of fluids, 202 Refpiration, on the change effected in the air by, 40 Richter, 71 Rings, phofphoric, accounted for, 64. Rittenhoufe, Mr. 110 Ritter, Mr. his experiments with the elec- tric pile, 176—His experiments on mag- netifm, 184, 212——His experiments on light, 214, 293 Roads, machine for clearing them from mud, 29 R. T. on the difficulty of obtaining alu- mine in a ftate of purity, 141 Rumford, Count, obfervations on his doc- trine refpeéting fluids as non-conduétors of heat, 134, 169, 198 S. Sale of his Majefty’s fpare fheep, 280 Salt, common, utility of adding it to hay, 237 ~— of lead, Prouft’s, 286 Salts, triple, of platina, caufe of the dif- ferent colours of, 118 Scapement, detached, defcription of a, 50 Scheele, 90, 207; 286 Science, on its ftate among the earfler nae tions of antiquity, 27 Scientific news, 62, 142, 222 Sea, table of its temperature compared with the atmofphere, 331 Seguin, 42 Serpente, on the fafcinating faculty afcrib- ed to, 58 Serviere, Monf. Grollier de, 35 Seymour, Lord Hugh, 66 Shark, ternperature of the ftomach of one when taken, 132 Sheep, wafhing them recommended, 96 —Report of the ftate of his Majefty’s flock of fine wooled Spanifh, 177—~ Improvement in the carcafe of the Me- rino, 278 Signs, telegraphic, by the human figure, 165 Silver is made brittle by galvanifm, 35 Sines and tangents, table of, 62 Sloane, Sir H. 60 Snow, on its formation, 73 Soap-fuds the beft menftruum for clean- fing wool, 95 Solar fpe€trum, is feparable into two feries of rays, the one coloured, the otherche- mical, 216 Somerville, Lord, 278 Species, mineralogical, can only be fepara- ted by the exterior charafters, 252 Spectacles, examination of the perifeopic, 38 Spheroidal triangles, new problems in, 153 Squares, very extenfive table of, 62——Eafy method of completing them, rgo Steam, powerful effect of its expanfion,26z. Steam-engines, attempt to reduce the con fumption of fuel in, 169—Improvement in the conftruction of, 162 Stone, containing potafh, examination of a, 127—Fact refpeCting water heated im a boiler of, 169 Sublimate, blue, of platina, chemical .ex-- amination of, 120 : Sulphuret INDEX. Sulphuret of lime, the beft teft for atmo- fpheric air, 42 Sulzer, 235 Sun, fpontaneous inflammation from its action, 219 Symner, 71 T. Table, of the going of three chronome- ters, 68 ——- of the relative preffures of the at- mofphere, temperatures and expanfibi- lity of fteam, 263 —- of fines and tangents, 62 ——- comparative, of the temperature of the feaand atmofphere, 131 ——- very extenfive, of fquares and cubes, 63—Eafy method of completing, 150 Tangents, tables of fines and, 62 Telegraph, formed of the human figure, 164—Mechanical additions to, 167 Temperature of the atmofphere and. fea, comparative table of, 13% “Tennant, Smithfon, Efq. difcovery of two new metals by, z20 Thompfon, Dr. 45, 139, 145; 198—On the oxides of lead, 280 Thouvenel, 77 Time-pieces, of an early date, 36 Tollet, Mr. 278 Torrefaction of vegetables increafes their tendency to fpontaneous inflammation, 233 Townley, Mr. 235 Tranfmutation of metals, antiquity of a belief in the, 28 Triangles, fpheroidal, new problems in, 151 Tromfdorff, 127 Trough, galvanic, improvement in, 79 T.S. T on the difappearance of a mix- ture of oxigen and hidrogen over water, 301 Turnery of an early date, 36 Vv. Van Marum, 177—On Ritter’s galvanic experiments, 212 Vapour, a mephitic probably emitted~by fome animals, 60 Varnith, eafy method of preparing copal, en nae, Vauquelin, on a new earthy phofphate found in the bones of animals, but not in thofe of men, $5—On the yoik of wool; andon the cleanfing and bleach ing of wool, 90—His analyfis of arfe~ niate of copper, 195, 221, 248, 288 Velocity of a body projeéted from the moon to the earth, methods of inveftigating, 22 Vegetables, dry, attract water, 243 Virgil, 108 Volta; 172, 177, 203 Vofmaer, Mr. 5%, 103 U. Urine, its ation in fcouring wool, 95 Ww. Wales, Mr. 66 Walker, Mr. A. his horfe-mill, 37 Mr. E. on the methods of ob- ferving the longitude at fea, and on the- accuracy of the mean refult from anom- ber of chronometers, 65 Water, its decompofition known to the ancients, 28—Its action on the yolk of wool, g0-—Dses not cleanfe wool alone, 94—Apparatus for filtering, 126—Dves not diffolve air, 149—Heated in a boiler of ftone, fact refpe€ting, 169—Aétion of alcohol on, 201—Is repelled by effen- tial oils, 203—Its ation on dry ve- getables, 24.3—Is attracted by dry at- mof{pheric air, 245—Beit method of im- pregnating it with a gas, 300—Slow ab- forption of a mixture of oxigen and hi- drogen over, 301 Watfon, Dr. 289, 291 Watt, 72, 262 Webfter, Mr. 268 Wetton, Mr. I. 169 Wilkinfon, C. Efq..om the means of fim- plyfying and improving the galvanic ape c paratus, INDEX. Wool, confiderations on the cleanfing and bleaching of, go—Lofs of weight by fcouring,, 96—Improvement in, 278 Woolf, Mr. his method of meafuring the contents of a pipe, 64—Account of his improvement in the conftru@tion of: fteam-engines, 262 paratusy r—-On galvanifm, 70, 1725 206 4 : Wind, its influence on the formation. of {now, 75 Winkelmann, 233. Winterbortoin, Dr. defcription, of his ma- - chine for clearing roads of mud, 29 , Wire, comparative deflagration, of, by eleew tricity and galvanifm, 205, AW. N. on the arrangement of different galvanic apparatus, 3—-On an Egyptian Jock of very high: antiquity, 115 Wollaftony Dr. examination of his perif- copic Apectacles, 38--On certain che- mical effeéts of light, 293 ‘Wood-copper, a fpecies of arfeniated cop- pers 258 Y, Yellow precipitate obtained from platinay. 120 Yolk of wool, experiments in the, g90== Component parts of, 93—Its principal fource is the humour of the tranfpira- tion, 94—Its acrimony probably hurtful to the living animal, 96 THE END OF THE EIGHTH VOLUME... Printed by W. Stratford, Crown Court, Temple-Bars ‘ Sea * ere ees + os : = Seccossseteesrss ed At 2) pyeiye beigh rset Stress sstliiieyeee Ose ol olaee ese ee eee Soecrwere ore Pyerese eres sere SritsieestoS tate. 7 Torah iaks ee see e=ee ors rest ps Bo ae ar) os tS = ceed cogecace mi ee a ae oy | TBE? 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