Aa : r+ Nee Pn sania e ae “i 4 ), ae : ~ * > ae Bri: Jaan “ae certs > / A tS I Da PHILOSOPHICAL MAGAZINE: THE VARIOUS BRANCHES OF SCIENCE, THE LIBERAL AND FINE ARTS, AGRICULTURE, MANUFACTURES, AND COMMERCE. — BY ALEXANDER TILLOCH, HONORARY MEMBER OF THE ROYAL IRISH ACADEMY, &c. &c. &c. ae z 2 —— ‘ *« Nec aranearum sane textus ideo melior quia ex se fila gignunt, nec noster vilior quia ex alienis libamus ut apes.” Just. Lips. Monit. Polit. lib. i. cap. 1. - ee Re VOL... XXIV. Lor FEBRUARY, MARCH, APRIL, and MAY 180. » a as ~. LOND Orn: £ Printed by R. Taylor and Co., 38, Shoe Lane, Fleet Sirect: And sold by Messrs. Ricnanpson; Caperr and Davies; Lonoman, Hurst, Rees, and Orme; Symonps; Murray; Hicurer; Vernox amd Hoon; Harpinc; London: Berry and Brapeuts, Edinburgh; Bras and Rei, and D. Nevin, Glasgow; and Girgrrr and Hopces, Dublin. 1806, Ava figs My tty qe ‘ ~— on RA SURES ae be Peay | ES i et eee GR ACCES en . : Nara B ne yess ' ry ‘ ag ¥ ; $ {UTOMUGAM JAVTANOMOL Ne ania eat AN a zs ih * y a , ~ . vee i Soa be rg = ~ ey: é Sip ee ; J ; ry Pa *, tebe Pe hay " Lis ' a CONTENTS OF THE TWENTY-FOURTH VOLUME. 1. ANALYSIS of the Chromate of Iron from the Ouralian Mountains in Siberia. By A. Lavuecirr .. » Page 3 II. On the Tendency of Elastic Fluids to D vali punch each other. By Joan Darron... TII. On the Absorption of Gases by Water ‘and jettierk oye quids. ByJoun Dattron.. .3) yh IV. An Experimental Inquiry into the. Matane “6 Gravelly and Calculous Concretions in the Human Sulject ; and the Effects of Alkaline and Acid Substances on them, in and out of the ae oe THOMAS phage M.D. MR. Tete, 67125 V. The Syphon applied 4 to the W orm Tub as a akef rigerator ; or, A Plan for conveying Water. in any Quantity te a Worm Tub of the largest Dimensions, if perfectly Air tight. By ALEXANDER Jounston, Engineer. .. 37 VI. Description of a Cometarium invented ly Ez. WALKER, Esq. ft Veen OT VI. A Blgchipiton af a Pea ty hag Cacnshons, or Indian Rubber; with some Reflections on the Cause of the Elas- ticity of this Substance. In a Letter to Dr. Hotme 39 VIII. Remarks on Urine, and the Prognostics which are de- rived from it. By Dr. CoLLennucH .. «Tops 44 IX. Twenty-sixth Communication from ait Teonwson, relative to Pneumatic Medicine... ah 47 X. On anew Black Dye to le applied to ar, Gas of Linens and Stuffs. By M.Henrmpstrapt, of Berlin .. 49 XI. New Experiments on the Respiration of Atmospheric Vol, 24. No. 96. May 1806. a ‘ Air, CONTENTS. Air, chiefly with respect to the Absorption of Azote and the Respiration of Gaseous Oxide of Azote. By Pre- Fessor Parr, LS ae ne ae XII. Additional Experiments and pAherks on an artificial Substance which possesses the principal characteristic Pro- perties of Tannin. By Cuarves Harcuetr, Esq. SN Se 7 ae XIII. On the Oxides of Gold, “Tin, al ‘aver Metals; 3 with Hints for extending their Uses in Dyeing. Communicated in a Letter to M. BertHOLLET by M. Joan Micnarn HAUSSMAN .. 69 XIV. On the partial Fusion of Metals o ihe Electeie Dis- charge. Bya Correspondent .. .. esth4, Bye XV. On the Reproduction of Buds. By THeiiae ANDREW Knicut, Esq. F.R.S. Ina Letter to the Right Hon. Siz Josupw Banxs, KiBuP.R.S. Se 75 XVI. Proceedings of Learned Societies .. .. «. 8} XVII. Intelligence and Miscellaneous Articles .. .. 91 XVIII, On the Possibility of naturalizing the Cachemire Goat of India to the Climate of Europe: in a Letter from Dr. De Carro, eA Vienna, to Professor Pictser, of Ge- mevad.s o SURF OT XIX. An issn Yy on Cie Pita, # ated Gascd and the State of Water in the yee 5 By Mr. Joun GovcH .. . Sr Nb, XX. An wien tinea Inquiry int vie Wan of Gravelly and Ca Lealoids Concretions in the Human Suljeci ; and the Fiffects of Alkaline and Acid Substances on them, in and out of the Body. By THomas Ecan, M.D. M,R.I.A. 114 XX. Extract of a Memoir of Messrs. Fourcroy and VAU@UELIN upon Guano, the natural Manure of the South Sea Islands near the Coast of Peru. Read before the National Institute. Drawn up by A. LaucieR 126 XXII. Analysis 3 Birdlime. By M. Bovuitton-La- GRANGE :. 131 XXII. On a new Peat ay Wood. By M. Patten. TIER °.. elas’, SESS XXIV. Uccount of a ‘Series oF “Experiments; showing the. : E affects CONTENTS. Exffects of Compression in modifying the Action of Heat. By Sir James Haut, Bart. F.R.S. Edin. .. ., 140 XXV. Additional Experiments and Remarks on an arti- Jicial Substance which possesses the principal characteristic Properties of Tannin. By Cuarves Harcuertt, Esq. POM AG a gh) CROTON. AS be 2eanSg XXV4. 14 simple and accurate Mo: de of iiereibsthed Gaso- eneters for Purposes where uniform Pressure ts elentin?, ty the Application of the Hydrostatic Regulator. By JosErPH STEEVENS, Esq. be, Hee cakes. (ian3 XXVIII. Process employed to obtain a Black AaMicl invented dy Mr. Ciranke, an hc and introduced into Commerce; its Use in marking Linen in a solid and dura- tle Manner, and its Application for printing Cottons or Stuffs. By M. Wermestant, of Berlin’ .. .. 165 AXVIHI. Letter of Messrs. Cronr and Petrrinr to Pro- Jfessor Pacceiant, of Pisa, on the Has Production of Muriatic Acid by Galvanism 4, RE eee KXIX. On the Decomposition of Wi ‘en by Galvanism. By Jouw Cutusertson, Esq.) 2.00.23. W170 KXX. Notice of Experiments made ly the Galvanic Society of Paris on the Discovery announced by M. Paccwiant of the Composition of the Muriatic Acid .. ..° 1792 XXXII. Extract of a new Letter of Dr. Francis PaAc- cuIANr, Professor of Natural Philosophy in the Univer- sity of Pisa, to M. Vasnoni, upon the Composition of the Murtatic Acid -.. .. Leen) TG XXXII. Proceedings of Learned Soc dais ee ae LED AXXITII. fitelligenae and Miscellaneous Articles .. 188 XAXIV. Account.of a Series of Experiments, showing the Effects of Compression in modifying the Action of Heat. By Sir James Haut, Bart. F.R.S. Edin... 193 XXXV. A new Fact in Galvanism. Communicated by a Correspondent .. .. Sent "oh wink seule Rs ont SO AXXWVI. On. Vaccination. An Beciiabhation oP several of the Mis-statements of Dr. Rowtey. re Mr. J. J. Haw- KINS, Of Islington .. .. ‘ f ‘ . 204 KXXVIT. On the es hod e extracting Spirits pon o- tatoes. CONTENTS. tatoes. By M. pasa Chemist to the Military Hos~ pital at Hanau... .» 209 XXXVIIL. Means of destroy set the eres ana Caterpillars which attack Fruit Trees. By Madame Gacgon Durour 213 XXXIX. Experiments upon the Gaseous Oxide of Azote, made at a Mecting of Amateurs, of Toulouse. Described by M. Dispan, Professor of Chemistry in the Institution of that City ooo ak, id, YEtS XL. Report of Cases in ve Fesiery Pisce ays from the ist of Jenuary to the 31st of March 1806. By Joun Taunron, Esq. Surgeon to the City and Fins- bury Dispensaries, and Lecturer on Anatomy, Physiology, and Surgery .. . nail ee. XLI. On the Galati. of Metals i in nan, and particu- larly the Oxidution of Iron. Read in the French National Institute ly Mz: TurnarpD .. - wiip223 XLII. On the Combination of Antimony wtieh Tin. By M. THEN ARD oer ee . ee ee 236 XLII. Abridgment of aug P ann w iil on the appa- rent Magnitude of the horixontal Moon, and published at sundry Times. To which are added, new Experiments to prove the Truth of the Author’s Theory, and to exhibit a clear Representation of the Phenomenon on ic Prin- ciples. By Ez. WALKER, fog. .. 240 XLIV. Extract of a Letter from M. Laveoue DE Buc, of Milan, to Professor Pictr:r, of Geneva, on the Pro- duction of Murtatic Acid and Soda ly the Galvanic De- composition of Vater... 244 XLV. Twenty-seventh Conmmaniiialion ie Dr. Tansee - TON, relative to Pneumatic Medicine .. .. .. 246 XLVI. Twenty-eighth Communication on Pneumatic Medi- cine, sent ly Dr. Toornton, from Mr. Hitz, Surgeon 247 XLVIT. On the Electrogene of Scumipr. By Count Stern- BERG, Vice-president of the Electoral Regency of Ra- LL 250 XLVUI. Letter.of M. Onsrzp, Prafaasir of Philosophy at Copenhagen, CONTENTS. Copenhagen, to Professor PicTET of Geneva, upon Sond- rous Vibrations .. e853 XLIX. On the Use of the lista in the Skulls v Ani- mals, By Mr.B.Grpson ..°. 256 L. On the Existence of Phosphate of Magnesia in Bites By M.Fourcroy ... . ae ate bere itera Oa LI. Notices respecting New opts AC Se aan ter pee 4 LII. Proceedings of Learned Societies .. «2 «. 271 LILI. Intelligence and Miscellaneous Articles... .. 282 LIV. On Transit Instruments. By Ez. WALKER, Esq. 289 LV. Account of a Series of Experiments, showing the Effects of Compression tn modifying the Action of Heat. By Sir James Haru, Bart. F.R.S. Edin. 2) = 298 LVI. Observations and Advices respecting Improvements compatible with the quickest Manufacture of Muscovado Sugar, and conducive to the Melioration of the Rum. By Bryan Hicerns, M.D. .. . te tas ee LYII. Letter of M. Tarpy pE La Bagcee to Professor Picrer, of Geneva, upon the Experiments of Mr. Brp- DLE, relative to the Density of fruxen Mercury .. 322 LVIII. Analysis of the sulphuretied Oxide of Manganese of Naygag. By M.VavauELiIn .. vest aren) See LIX. Memoir on the Eremophilus and Anninienus, two new Genera of the Order of Apodes. By M. pk HumBo.ipt 329 LX. Memoir on a new Species of Pimelodus thrown out of the Volcanoes in the Kingdom of Quito; with some Particulars respecting the Volcanoes of the Andes. By M.peHumsBorpT .. ihahey eee 6 15, LXI. Memoir on a new Species ie ‘Monkey, Foihell in the eastern Declivity of the Andes. By M. pe HumBoupt 339 LXII. Analysis of the Hot Springs at Bath. By Mr. Rx- CHARD Puiiips, Member of the Askesian and of the British Mineralogical Societies .. ESL eM NT Sid LXIIT. Proceedings of Lean ned Bicester’ ran. abe BOE LXIV. Intelligence and Miscellaneous Articles = 366 THE THE PHILOSOPHICAL MAGAZIN YE. I. Analysis of the Chromate of Iron from the Ouralion Mountains in Siberia. By A. Lavcier*®. M. PonTIER, in a tour made through the department of Var, in the year 7, found, near La Bastide de la Cassade, a mineral, which he sent to the Council of Mines under the name of blende, and which M. Tassaert first discovered to be a combination of chromic acid and oxide of iron. His opinion was afterwards confirmed by M. Vauquelin in the tenth volume of the Journal de Mines; where he at the same time announced the proportions of chrome and iron, together with the presence of alumine and silica. M. Meder has since found in Siberia, in the Ouralian mountains, on the banks of the Wiasga, a substance very similar to the mineral of Var. A specimen of this having been given to me by M. Steinacher, member of the corporation of apothecaries of Paris, who had received it from count Mussin Puschkin, counsellor of the mines of Russia, I conceived it might be useful to examine it, and compare the results of my examination with the analysis of the mineral of Var published by M. Vauquelin, fully per- suaded that my labours would be rewarded with some ad-~ vantage. Physical Properties. Although the mineral of Siberia be very similar in ap- pearance to that of Var, an atttentive examination of it would lead us to suspect, that in the first of these the metal is purer and more abundant than in the second ; its * From Annales de Museum d’Histoire Naturelle, No. 35. Vol. 24, No. 93. Feb. 1806. Ag fracture 4 Analysis of the Chromates of Iron fracture is lamellar, and not granulated ; its metallic “bril- liancy is more vivid, and it evidently contains a smaller admixture of earthy matters. The specimen in my pos- session shows spots of green on some parts of its surface, which are discovered to be oxide of chrome. The spe- cific gravity of the two also serves to support my conjecture regarding them. That of my specimen is 40579, while the specific gravity of the mineral of Var is only 4-0326. This difference in weight necessarily makes a difference in the proportions of the metallic part of the two chromates ; and, as we shall presently see, the analysis agrees com- pletely with this physical property. Chemical Examination. 1. When strongly calcined it loses about 1-100th part of its weight, and acquires a reddish brown colour. Having placed 100 parts of this mineral reduced to an impalpable powder, together with 300 parts of pure potash, in 3 cruci- ble of platina, I exposed the whole toa strong heat. The mass, when removed from the fire, and nearly cooled, was in part of a green and in part of an orange colour. The water which [ added to it assumed a rich citron yellow, exactly similar to the colour of chromate of potash. When the mass no longer gave a tinge to distilled water, I digested it in very weak muriatic acid, with the intention of sepa- rating what part of the oxide of iron had been set free by the action of the potash, without touching, in any degree, the chromate of iron, which was still undecomposed. I now washed the remaining substance again, till the water came off insipid, and a second time melted it with a portion of pure potash. In this way I heated the mineral six different times, al- ternately with potash and muriatic acid; setting aside the alkaline and acid solutions, that I might examine them se- parately. The residuum consisted of a brownish gray matter, weighing 0-90: muriatic acid took up from it a little iron, and the remainder was completely dissolved in nitro-nuuriatic acid. . from the Ouralian Mountains in Siberia. 5 acid. This solution, which was of a reddish brown co- lour, let fall a yellow precipitate on the addition of muriate of ammonia, and a deep red precipitate by the muriate of tin at the minimum of oxidation: it suffered no precipita- tion by prussiate of potash, and formed with soda a triple salt of a beautiful red colour. It was therefore no other than a portion of platina which had been separated from the crucible by the six successive manipulations ; and there was every reason to believe that the alkali and acid had completely dissolved the constituent ingredients of the mi- neral in question. Examination of the Alkaline Solution. 2. This solution had a very beautiful deep yellow colour. The last portions of :the solution had a greenish tinge, which disappeared on the spontaneous deposition of a brown substance in small quantity, which I discovered to be oxide of manganese. I poured, by degrees, into the so- lution, evaporated to one-half its former bulk, such a quan- tity of nitric acid as saturated the caustic portion of alkali; and a precipitate fell to the bottom, which I collected upon a filter, then washed it, and submitted it to calcination. It weighed 11 hundredth parts, and was set aside for future examination. The addition of a slight excess of nitric acid produced no precipitation but merely a violent effervescence, and caused the solution. to assume a very deep orange red co- Jour. When evaporated to dryness it left a saline residuum of a fine yellow colour, which dissolved completely in wa- ter: the solution, when acidulated with nitric acid, furnished by the nitrate of mercury a red precipitate, which after being dried in the air weighed 430 parts ; and these by ¢al- cination were reduced to 52 hundredth parts of an oxide of ehrome, having a beautiful green colour. 3. The matter precipitated in No. 2 by the nitric acid was melted with thrce parts of caustic potash; and the mass, when mixed with water, dissolved completely in muriatic acid. The solution, when evaporated to dryness, AS left , 6 Analysis of the Chromate of Iron left a residue, a part of which was insoluble in water, and weighed, after calcination, only one-half part: it consisted of a mixture of silica and oxide of iron. I now poured into the water which contained the soluble portion of the resi- duum a quantity of ammonia; and a white flocculent pre- cipitate appeared, which formed with the water a jelly, and exhibited all the characters of alumine: it weighed 10 hun- dredth parts aid a half. From these experiments on the alkaline solution we may- conclude that it contained chrome, alumine, a little oxide of manganese, together with sume particles of iron and silica. / Examination of the Muriatic Solution. 4. The colour of this solution, which contained an excess of acid, was reddish yellow. On the addition of a solution of caustic potash a flocculent matter of a brownish red se- parated, which, when washed and mixed with the small quantity of oxide of iron already obtained, both from the alkaline solution and from the residue, discovered to be pla- tina, weivhed, afier being calcined, 34 hundredth parts. The solution continued still coloured after the separation of the oxide of iron, although the re-agents indicated the presence of no chrome: I was therefore convinced that it owed iis tinge to a small quantity of platina. The excess of caustic potash which I had added contained some par- ticles of alumine, and these I separated by means of mu- riate of ammonia. 5. With a view to ascertain the purity of the oxide of iron which had the usual colour and appearance of this oxide, I melted it again with pure potash: but water, when added to the mixture, received no tinge, and the re-agents indicated the presence of no foreign substance. We must therefore infer that the very weak muriatic acid which I miade use of dissolved nothing but the oxide of iron. From from the Ouralian Mountains in Siberia. 7 From the above analysis it appears that the chromate of iron of Siberia contains in the 100 parts, Oxide of chrome ~ 53 Oxide of iron - - 34 Alumine - - = 11 Silica E = ne 1 99 Traces of manganese and loss — 1 These results are nearly similar to what M. Vauquelin, obtained from the chromate of Var. Chromic acid - - 43° Oxide of iron - - 9AFT Lon Alumine = - - 20'3 Silica - - - 2 100 Does the chrome exist in the state of acid or in that of oxide in the mineral termed chromate of iron? M.Godon de Saint-Mesmin, in a memoir upon the combinations of chromic acid, read at the National Institute, has discussed this question, and is inclined to think that it is in the state ef oxide. M. Vauquelin, in his report of this memoir, seems disposed to adopt the same opinion. I shall mere- ly state, in support of this idea, an experiment which renders it probable. If the green oxide of chrome be gently calcined with pure potash, it is almost immediately brought to the state of an acid: we are therefore not war- ranted in asserting that chrome exists as an acid in the chromate of iron, while by the presence of potash this con- version of the oxide is rendered likely. It is then, at least, highly probable that the mineral which till now has re- ceived the name of chromate of iron, is, in fact, no other than a combination of the oxides of iron and chrome. Since I finished my examination of the chromate ef iron Aa4 of s Tendency of Elastic Fluids to Diffusion. of Siberia, I have learnt that M. Lowitz has also analysed this substance. Iam ignorant of the exact proportions of its ingredients, according to his experiments, but if I may judge from the note relative to this subject which appeared in the Journal de Physique, his results were nearly the same with mine; for he announces that he found it to coniain more than half its weight of oxide of chrome, together with iron, alumine, and a little silica. II. On the Tendency of Elastic Fluids to , Diffusion through each other. By Joun Darron*, In an early period of pneumatic. chemistry it was disco- vered that clastic fluids of different specific gravities being once diffused through each other, do not of themselves se- parate, by long standing, in-such manner as that the hea- viest is found in the lowest place; but, on the contrary, remain in a state-of uniform and equal diffusion. Dr. Priestley has given us a section on this subject (vide Experiments and Obsery ations, &c. abridged, vol. i. p- .441), in which he has: proved the fact above riventioned In 2 sa- tisfactory manner; and every one’s experience since, as far as 1 know, has coincided with his conclusions. | He has not offered any conjecture concerning the cause of this deviation from the law observed by inelastie fluids ; but he suggests, that ‘if two kinds of air of very different specific gravities were put into the same vessel, with very great care, without. the least agitation that might mix or blend them together, they might continue separate, as with the same care wine and water may be made to do.” The determination of this point, which seems at first view but a trivial one, is of considerable importance; as from it we may obtain a striking trait, either of the agree- ment or disagreement of elastic and inelastic fluids in their mutual action on each other. It is thereiore the subject of the following experiments to ascertain whether two elastic fluids, brought into contact, * From Manchester Tratisactions, second series, vol. i. could Tendency of Elastic Fluids to Diffusion. 9 could intermix with each other independently of agitation. The result seems to give it in the affirmative beyond a doubt, contrary to the suggestion of Dr. Priestley, and establishes this remarkable fact, that a lighter eiastic fluid cannot rest upon a heavier, as is the case with liquids ; but they are constantly active in diffusing themselves through each other till an equilibrium is effected, and that without any regard to their specific gravity, except so far as it acce- lerates or retards the effect, according to circumstances. The only apparatus found necessary was a few phials, and tubes with perforated corks: the tube mostly used was one 10 inches long, and of 1-20th of an inch bore; in some cases a tube of 30 inches in length and 1-3d inch bore was used: the phials held the gases that were subjects of ex- periment, and the tube formed the connection.’ In all cases the heavier gas was in the under phial, and the two were placed in a perpendicular position, and suffered to re- main so during the experiment in a state of rest: thus cir- cumstanced, it is evident that the effect of agitation was sufficiently guarded against; for, a tube almost capillary, and ten inches long, could not be instrumental in propa- gating an intermixture from a momentary commotion at the commencement of each experiment. First Cuass. Carbonic Acid .Gas, with Atmospheric Air, Hydrogenous, Axotic, and Nitrous Gases. 1. A pint phial filled with carbonic acid gas, the 30 inch tube and an ounce phial, the tube and smal] phial being filled’ with common air, were uscd at first. In one hour the small phial was removed, and had acquired no sensible quantity of acid gas, as appeared from agitating lime water init. In three hours it had the acid gas in great plenty, instantly making lime water milky. After this it was re- peatedly removed in ‘the space of half an hour, and never failed to exhibit signs of the acid gas. Things remaining just the same, the upper phial was filled with the different gases mentioned above repeatedly, and in half an hour there was always found acid sufficient to make the phial, one-half 10 Tendency of Elastie Fluids to Diffusion. one-half filled with lime water, quite milky. There was not any perceptible difference, whatéver gas was in the upper phial *. SsconpD CLass. Hydrogenous Gas, with Atmospheric Air and Oxygenous ‘Gus. 1. Two six-ounce phials were connected by the tube of a tobacco pipe three inches long, the upper containing hy- drogenous gas, the lower atmospheric air: after standing two hours the lower phial was examined; the mixed gases it contained made six explosions in a small phial. The gas in the upper also exploded. 2. Two four-ounce phials connected with the ten-inch small tube stood two days, having common air and hydro- gen gas. Upon examination the upper was found to be one-third common air by the test of nitrous gas. The gas in the under exploded smartly; that in the upper mode- rately, with a lambent flame. 3. Two one-ounce phials were connected by the ten-inch tube, containing common air and hydrogenous gas: in three hours and a half the upper was about one-third com- mon air, and the under two-thirds; the former exploded faintly, the latter smartly. 4. Two one-ounce phials were connected as above; the under containing gas about three-fourths oxygenous, the upper hydrogenous: in three hours the latter was one-fifth oxygenous, and the former about one-half; the upper ex- ploded violently, the under moderately. 5. Two one-ounce phials were’ again connected, the lower having atmospheric air, the upper hydrogenous gas ; they stood fifieen hours, and were then examined: the upper gave 1°G7 with nitrous gas, the under 1°66. Hence it is evident that an equilibrium had taken place, or the two gases were uniformly diffuscd through each other im both phials. * The small tube of tea inches was then used, and a phial of common air; in one hour much acid gas had come through, as appeared by lime Water. THIRD Tendency of Elastic Fluids to Diffusion. 1k Tuirp CLaAss. Nitrous Gas, with Oxygenous Gas, Atmospheric Air, Hydrogenous and Axotic Gases. ‘The results of the preceding experiments upon gases that have no known afhnity for each other, were conformable to what, d priori, I had conceived; for, according to my hypothesis, every gas diffuses itself equably through any given space that may be assigned to it 5 and no other. gas being in its way can prevent, though it may considerably retard, this diffusion. But in some of the following ex- periments, in which the two gases are known to have a chemical affinity for each other, I expected different results from what were found; perhaps without sufficient reason. For chemical union cannot take place till the particles are brought into contiguity; and the elastic force which sets them in motion appears, from the above experiments, to be a principle diametrically opposite to affinity. That cir- culation of elastic fluids, therefore, which we have now be- fore us, cannot be accelerated by their having a chemical affinity for each other. Another circumstance deserves ex- planation: when nitrous and oxygenous gas are in the two phials, the residuary gases after the experiment are nearly as pure as before ; because those portions of them that meet in the tube form nitrous acid vapour, which is absorbed by the moisture in the phials, and therefore does not conta- minate either gas. 1. Two one-ounce phials were connected with the small tube, the under containing nitrous gas, the upper atmo- spheric air. After three hours the upper phial was taken off, when a quantity of air was perceived to enter, as was expected: the air in the upper phial was scarcely distin- vuisbable from what it was at first; that in the under phial was still so much nitrous as to require its own bulk of common air to saturate it. 2. The above experiment was repeated, and the upper phial drawn off when the whole was under water, in order to prevent communication with the atmosphere. About one-sixth of an ounce of water entered the phials, to com- 7 pensate 12 Tendency of Elastic Fluids to Diffusion. pensate the diminution. Remaining air in the upper phial was a very little worse than common air; it beimg of the standard 1:47, when the former was 1°44. _‘ The gas in the under phial was still nitrous, and nearly of the same purity as at first; for three parts of it required four of atmospheric air to saturate them. 3. Nitrous gas and one two-thirds oxygenous were tried in the same way. ‘After four hours the apparatus was taken down under water. The upper phial was two-thirds filled with water, and the gas in it was partly driven down the tube into the other phial, by which, and the previous pro- cess, the nitrous gas was completely saturated, and nothing but azotic, with a smail portion of oxygenous, were found in the under phial. The remaining gas in the upper phial was still one-half oxygenous. : 4. Nitrous gas and hydrogenous. In three hours the upper phial was one-fourth nitrous, and of course the under must have a like part of hydrogen. 5. Nitrous gas and azotic. After three hours the upper phial was one-fifth nitrous. In the two last experiments the quantity of nitrous gas in the upper phial was less than might be expected; but the tube was at first filled with common air, and some must enter on connecting the apparatus, which is sufficient to account for the results. Fourtu Ctass. Axotic Gas, with Mixiures containing Oxygenous Gas. 1. Azotic gas and one two-thirds oxygenous. After standing three hours the upper phial was of the standard 1°78, or about one-fourteenth oxygenous. 2. Azotic gas with atmospheric air. After standing three hours the upper phia! was not sensibly diminished by nitrous gas; the under phial, however, had lost two per cent., or one-tenth of its oxygen, The reason of this was, that the azotic gas in this experiment, having been just made for it from nitrous gas, this last had not been com- pletely saturated with atmospheric air, and hence had seized upon all the oxygen ascending into the upper phial. Having Tendency of Elastic Fluids to Diffusion. 13 Having now related all the experiments I made of any importance to the subject, it will be proper to add, for the sake of those that may wish to repeat some of them, that great care must be taken to keep the inside of the tube dry ; for if a drop of water interpose between ihe two gases, I have found that it effectually prevents the intercourse, Glass tubes should therefore be used, that one may be sa- tisfied on this head, as the obstruction will then be visible. I shall make no further comments on the above experi- ments by way of explanation; because, to those who under~ stand my hypothesis of elastic fluids, they need none: and I think it would be in vain to attempt an explanation any other way. I cannot however, on this occasion, avoid ad- -verting to some experiments of Dr. Priestley, which few modern philosophers can be unacquainted with; [ mean those relating to the seeming converston of water into air. (Vide Philos. Transact. vol. Ixxiil. p. 414; or his. Experiments abridged, vol. u. p. 407.) He found that unglazed earthen retorts, containing a little moisture, when heated, admitted the external air to pass through their pores at the same time that aqueous vapour passed through the pores the contrary way, or outward; and that this last circumstance was ne- cessary to the air’s entrance. The retorts are air-tight, so far as that blowing into them discovers no pores; but when subjected to a greater pressure, as that of the atmo- sphere, or even one much short of it, they are not able to prevent the passage of elastic fluids. The fact of air passing into the retort through its pores, and vapour out of them at thesame time, are clegantly and most convineingly shown by ‘Dr. Priestley’s experiments, in which he used the apparatus represented in Plate VII. fig. 1. of the edition above referred to. The doctor confesses his explanation of these remarka- ble facts is very inadequate; and no wonder, for it is im- possible for him or any other to explain them on the coms monly received principles of clastic fluids. But we will hear what he says on the subject :—‘ At present it is my opi- nion that the agent in this case is that principle which we call attraction of cohesion, or that power by which water is raised in capillary tubes. But in what manner it acts in this i4 Tendency of Elastic Fluids to Diffusion. this case, I am far from being able to explain. Much less can I imagine how air should pass one way and vapour the oiher in the same pores, and how the transmission of the one should be necessary to the transmission of the other. I am satisfied, however, that it is by means of such pores as air may be forced through, that this curious process is performed ; because the experiment never succeeds but in such vessels as, by the air-pump at least, appear to be porous, though in all such.” The truth is, these facts, so difficult to explain, are ex- actly similar to those which are the subject of this memoir; only instead of a great number of pores, we have one of sensible magnitude—the bore of the tube. Let the porous . retort have the same elastic fluid within and without, in the one case; and the two phials contain the same elastic fluid in the other, then no transmission is observable in either: but if the retort have common air, or any other gas, without, and aqueous vapour, or any other elastic fluid, except the outside one, within; then the motion in and out commences, just as with the phials in similar cir- cumstances. In fact, this last observation has since been verified by Dr. Priestley himself, of which an account is given in No. 2, of the American Philosophical Transac- tions, vol. v. After alluding to his experiments above mentioned, he observes: Since that time I have extended and diversified the experiments, and have observed, that what was done by air and water will be done by any two kinds of air, and whether they have affinity to one another or not; that this takes place in circumstances of which I was not at all apprised before, and such as experimenters ought to be acquainted with, in order to prevent mistakes of considerable consequence.” The facts stated above, taken altogether, appear to me ‘to form as decisive evidence for that theory of elastic finids “which I maintain, and against the one commonly received, as any physical principle which has ever been deemed a subject of dispute can adduce. III. On [ 18 j Il. On the Absorption of Gases ly Water and other Li- _ quids. By Joun Datron*. te a quantity of pure water be boiled rapidly for a short time in a vessel with a narrow aperture, or if it be sub- jected to the air-pump, the air exhausted from the receiver containing the water, and then be briskly agitated for some time, very nearly the whole of any gas the water may con- tain will be extricated from it. 2. Ifa quantity of water thus freed from air be agitated m any kind of gas not chemically uniting with water, it will absorb its bulk of the gas, or otherwise a part of it equal to some one of the following fractions, namely, 1, 2-, 3+, 71-5 &c., these being the cubes of the reciprocals of the natural numbers 1, 2, 3, &c., or +» cE iitlt always being absorbed in the same proportion, as exhibited in the following table. It must be understood that the quantity of gas is to be measured at the pressure and tempe- rature with which the impregnation is effected. 38 Gea &e., the same gas Bulk absorbed, the bulk of Carbonic acid gas, sulphu- water being unity. retted hydrogen, nitrous ox- 1 ide}. —= 1 48 1 1 Olefiant gas of the Dutch Fra chemists. 1 Oxygenous gas, nitrous Sa tt cathe Fae we gas t, carburetted hydrogen i gas, from stagnant water. Pee sy Azotic gas, hydrogenous 4 - gas, carbonic oxide. ree ais None discovered. * From Manchester Transactions, second series, vol. i. + According to Mr. William Henry’s experiments, water does not imbibe quite its bulk of nitrous oxide: in one or two instances with me it has come very near it. The apparent deviation of this gas may be owing to the difh- culty of ascertaining the exact degree of its impurity. + About 1-26th of nitrous gas is usually absorbed, and 1-27th is recovera- 3. The 16 On the Absorption of Gases. 3. The gas thus absorbed may be recovered from the water the same in quantity and quality as it entered, by the means pointed out in the first article. 4. If a quantity of water free from air be agitated with a mixture of two or more gases (such as atmospheric air), the water will absorb portions of each gas the same as if they were presented to it separately in their proper density. Ex. gr. Atmospheric air, consisting of 79 parts azotic gas, and 21 parts oxygenous gas, per cent. Water absorbs ;'; of 77,2;, azotic gas = 1°234 a> of =%'5, oxygen gas = +778 Sum, per cent. 2°012 5. If water impregnated with any one gas (as hydro- genous) be agitated with another gas eaally | absorbable (as azotic), there will apparently be no absorption of the latter gas, just as much gas being found after agitation as was introduced to the water; but upon examination the resi- duary gas will be found a mixture of the two, and the parts of each, in the water, will be exactly proportional to those out of the water. ' 6. If water impregnated with any one gas be agitated with another gas less or more absorbable, there will appa- rently be an increase or diminution of the latter; but upon examination the residuary gas will be found a mixture of the two, and the proportions agreeable to article 4. 7. If a quantity of water in a phial, having a ground stopper very accurately adapted, be agitated with any gas, or mixture of gases, till the due share has entered the wa- ter; then, if the stopper be secured, the phial may be ex- posed to any variation of temperature without disturbing the equilibrium: that is, the quantity of gas in the water will remain the same whether it be exposed to heat or cold, if the stopper be air-tight. ble: this difference is owing to the residuum of oxygen in the water, each measure of which takes 34 of nitrous gas to saturate it when in water. Per- haps it may be found that nitrous gas usually contains a small portion of ni- trous oxide. / N.B. The o = by Water and other Liquids. 17 N.B, The phial ought not to be near full of water, and the temperature should be between 32° and 212°. 8. If water be impregnated with one gas (as oxygenous, and another gas, having an affinity for the former (as ni- trous), be agitated along with it, the absorption of the latter gas will be greater, by the quantity necessary to saturate the former, than it would have been if the water had been free from gas *. 9. Most liquids free from viscidity, such as acids, alco- hol, liquid sulphurets, and saline solutions in water, absorb the same quantity of gases as pure water, except they have an affinity for the gas, such as the sulphurets for oxy- gen, &c. The preceding articles contain the principal facts neces- sary to establish the theory of absorption ; those that follow are of a subordinate nature, and partly «educible as corol- laries to them. 10. Pure distilled water, rain and spring water, usually contain nearly their due share of atmospheric air; if not, they quickly acquire that share by agitation in it, and lose any other gas they may be impregnated with. It is re- markable, however, that water by stagnation, in certain circumstances, loses part or all of its oxygen, notwith- standing its constant exposition to the atmosphere. This I have uniformly found to be the case in my large wooden pneumatic trough, containing about eight gallons, or 1} cubic foot of water. Whenever this is replenished with to- lerably pure rain water, it contains its share of atmospheric air, but in process of time it becomes deficient of oxygen: in three months the whole surface has been covered with a pellicle; and no oxygenous gas whatever was found in the water. It was grown offensive, but not extremely so; it had not been contaminated with any material portion of * One part of oxygenous gas requires 3:4 of nitrous gas to saturate jt in water. It is agreeable to this that the rapid mixture of oxygenous and nitrous gas over a broad surface of water occasions a greater diminution than other- wise. In fact, the nitrous acid is formed this way; whereas when water is not present the nitric acid is formed, which requires just half the quantity of nitrous gas, as I have lately ascertained, Vol. 24. No. 93. Fel. 1806. B metallic 18 On the Absorption of Gases metallic or sulphureous mixtures, or any other ‘article to which the effect could be ascribed*. The quantity of azotic gas 1s not materially diminished by stagnation, if at. all. These cireumstances, not being duly noticed, have been the source of great diversity in the results of different phi- losophers upon the quantity and quality of atmospheric air in water. By article 4, it appears that) atmospheric. air expelled from water ought to have 38 per cent. oxygen; whereas by this article air may be expelled from water that shall contain from 38 to 0 per cent. of oxygen. _ The dis- appearance of oxygenous gas in water, I presume, must be owing to some impurities in the water which combine with the oxygen. Pure rain water that had stood more thana year in an earthen-ware bottle had lost none of its oxygen. 11. If water free from air be agitated with a small portion of atmosp'*eric air (as 1-15th of its bulk), the resi- duum of such air will/have proportionally less oxygen than the original: if we take 1-15th, as above, then the resi- duum will have only 17 per cent. oxygen, agreeably to the principle established in article 4. This circumstanee ac- eounts for the observations made by Dr. Priestley and Mr. William Henry, that, water absorbs oxygen ‘in _pre- ference to azote. 12. If a tall glass vessel, containing a small portion of gas, be inverted into a deep trough of water, and the gas thus confined by the glass and the water be briskly agitated, it-will gradually disappear. It is a wonder that Dr. Priestley, who seems to haye been the first to notice this fact, should have made any difficulty of it: the loss of gas has evidently a mechanical cause ; the agitation divides the air into an infinite number of minute bubbles, which may be seen pervading the whole water; these are successively driven out from under the margin of the glass into the trough, and $0 escape. 13. If old stagnant water be in the trough in the last experiment, and atmospheric air be the subject, the oxy- genous gas will very soon be alinost wholly extracted, and leave a residuum of azotic gas ; but if the water be fully * Tt was drawn from a leaden cistern. impregnated by Water and other Liquids. 19 impregnated with atmospheric air at the beginning; the residuary gas, examined at any time, will be pure atmo- spheric air. 14. If any gas, not containing either azotic or oxygenous gas, be agitated over water containing atmospheric air, the residuum will be found to contain both azotic and oxygenous gas. } . 15. Let a quantity of water contain equal portions of any two or more unequally absorbable gases; for. in3tance, azotic gas, oxygenous gas, and carbonic acid gas3 then let the water be boiled, or subjected to the air pump, and it will be found that unequal portions of the gases will be expelled: the azotic will be the greatest part, the oxygenous next, and the carbonic acid will be the least. For, the previous impregnation being such as is due to atmospheres of the following relative forces nearly, Azotic’ - = 21 inches of mercury Oxygenous - 9 ditto Carbonic acid 02 ditto consequently, when those forces are removed, the resili- ency of the azotic gas will be the greatest, and that of the carbonic acid the least; the last will even be so-small as not to overcome the cohesion of the water without violent agi- tation. Remarks on the Authority of the preceding Facts. In order to give the chain of facts as distinct as possible, Ihave not mentioned by whom, or in what manner, they were ascertained. The fact mentioned in the first article has been Jong known; a doubt, however, remained respecting the quan- tity of air still left in water after ebullition and the operation of the air pump. The subsequent articles will, 1 appre- hend, have placed this in a clearer point of view. In determining the quantity of gases absorbed, [ had-the result of Mr. William Henry’s experience.on the subject hefore me, an account of which has. been published in the Philosophical Transactions for 1803. By the reciprocal communications since, we have been enabled to bring the B2 resuits 20 On the Adsorption of Gases results of our experiments to a near agreement, as the quan- tities he has given in his appendix to that paper nearly ac- cord with those T have stated in the second article. In my experiments with the less absorbable gases, or those of the ad, 3d, and 4th classes, I used a phial holding 2700 grains of water, having a very accurately ground stopper; in those with the more absorbable of the first class I used an eudio- meter tube properly graduated, and of aperture so as to be covered’ with the end of a finger. This was filled with the gas, and a small portion expelled by introducing a solid body under water: the quantity being noticed by the quantity of water that entered on withdrawing the solid body, the finger was applied to the end, and the water within agitated: then, removing the finger for a mo- ment under water, an_ additional quantity of water entered, and the agitation was repeated ull no more water would enter, when the quantity and quality of the residuary gas were examined. In fact, water could never be made to take its bulk of any gas by this procedure ;_ but if it took g-10ths,. or any other part, and the residuary gas was 9-10ths pure, then it was inferred that water would take its bulk of that gas. The principle was the same in using the phial; only a-smal] quantity of the gas was admitted, and the agitation was longer. There are two: very important facts contained in the se~ cond article. The first is, that the quantity of gas absorbed is as the density or pressure. This was discovered by Mr. Witham Henry, before either he or Ehad formed any theory on the subject. The other is, that the density of the gas m‘ the water has aspecial relation to that out of the water, the distance of the particles within being always some multiple of that without. Thus, im the case of carbonic acid, &c. the di- stance within and without is the same, of the gas withiw the water is of the same density as without; in olefiant gas the distance of the particles in the water is twice that with- out; in oxygenous gas, &c. the distance is just three times as great within as without; and in azotic, &c. it is four times. This-fact was the result of my own inquiry.. The former by Water and other Liquids. 21 former of these, I think, decides the effect to be mecha- nical; and the latter seems to poit to the principle on which the equilibrium is adjusted. The facts noticed in the 4th, 5th, and 6th articles were investigated, @ priori, from the mechanical hypothesis, and the notion of the distinct agency of elastic fluids when mixed together. The results were found entirely to agree with doth, or as nearly as could be expected from experiments of such nature, The facts mentioned in the 7th article are of great import- ance in a theoretic view ; for, if the quantity of gas absorbed depend upon mechanical principles, it cannot be affected by temperature in confined air, as the mechanical effect of the external: and internal air is alike increased by heat, and the density not at all affected in those circumstances. I have tried the experiments in a considerable variety of tempera- ture without perceiving any deviation from the principle. {t deserves further attention. If water be, as pointed out by this essay, a mere recep- tacle of vases, it cannot affect their affinities: hence what is observed in the 8th article is too obvious to need explana- tion. And if we find the absorption of gases to arise not from a chemical but a mechanical cause, it may be ex- pected that all liquids having’an equal fluidity with water will absorb like portions of gas. In several liquids I have tried, no perceptible difference -has been found ; but this de- serves further investigation. After what has been observed, it seems nnnecessary to add any explanation of the i0th and following articles. Theory of the Absorption of Gases by Water, Sc. From the facts developed in the preceding articles, the following theory of the absorption of gases by water scems deducible ; 1. All gases that enter into water oii other liquids by means of pressure, and are wholly disengaged again by the removal of that pressure, are mechanically mixed with the liquid, and not chemically combined with it. 2. Gases so mixed with water, &c. retain their elasticity B3 or \ 22 On the Absorption of Gases or repulsive power amongst their own particles, just the same: in the water as out of it, the intervening water having no other influence in this respect than a mere vacuum, 3. Each gas is retained in water by the pressure of gas of its own kind incumbent on its surface abstractedly considered, no other gas with which it may be mixed having any per- manent influence in this respect. 4. When water has absorbed its bulk of carbonic acid gas, &c. the gas does not press on the water at all, but presses on the containing vessel just as if no water were in. When water has absorbed its proper quantity of oxygenous gas, &c. that is, = of its bulk, the exterior gas presses on the surface of the water with 44 of its force, and on the in- ternal gas with 3, of its force, which force presses upon the containing vessel and not on the water, With azotic and hydrogenous gas the proportions are $¢ and ,', respectively. When water contains no gas, its surface must support the whole pressure of any gas admitted to it, till the gas has, in part, forced its way into the water. 5. A particle of gas pressing on the surface of water is analogous to a single shot pressing upon the summit of a square pile of them. As the shot distributes its pressure equally amongst all the individuals forming the lowest stra- tum of the pile, so the particle of gas distributes its pressure equally amougst every successive horizontal stratum of par- ticles of water downwards till it reaches the sphere of influ- ence of another particle of gas. For instance, Jet any gas press with a given force on the surface of water, and Jet the distance of the particles of gas from each other be to those of water as 10 to 1; then each particle of gas must divide its force equally amongst 100 particles of water, as follows :— It exerts its immediate force upon 4 particles of water; those 4 press upon 9, the 9 upon 16, and so on according to the order of square numbers, till 100 particles of water have the force distributed amongst them; and in the same stratum each square of 100, having its incumbent particle of gas, the water below this stratum is uniformly pressed by the gas, and consequently has not its equilibrium disturbed by that pressure. When by Water and other Liquids. 23 When water has absorbed ,', of its bulk of any gas, the Stratum of gas on the surface of the water presses with 2! 6 of its force on the water, in the manner pointed out in the last article, and with 2; of its force on the uppermost stratum of gas in the water: the distance of the two strata of gas must be nearly 27 times the distance of the particles in the incumbent atmosphere, and 9 times the distance of the par- ticles in the waier.. This comparatively great distance of the inner and outer atmosphere arises from the great repulsive power of the latter, on account of its superior density, or its presenting 9 particles of surface to the other 1.. When gts is absorbed, the distance of the atmospheres becomes 64 times the distance of two particles in the outer, or 16 times that of the inner. The annexed views of perpendicular and horizontal strata of gas in and out of water, will sufficiently illustrate these positions. 7. An equilibrium between the outer and inner atmo- spheres can be established in no other circumstance than that of the distance of the particles of one atmosphere being the same or some multiple of that of the other; and it is probable the multiple cannot be more than 4. For-in this case the distance of the inner and outer atmospheres is such as to make the perpendicular force of each particle of the. former on those particles of the latter that are immediately subject to its influence, physically speaking, equal; and the same may he observed of the small lateral force. 8. The greatest difficulty attending the mechanical hypo- thesis, arises from different gases gbser ving different laws. Why does water not admit its bulk of every kind of gas alike ?>—This question I have duly considered: and though I am not yet able to satisfy myself completely, [ am seul persuaded that the circumstance depends upon the weicht and number of the ultimate particles of the several « gases ; those whose particles are lightest and single being least ab- sorbable, and the others more, according as they increase in weight and complexity *. An inquiry into the relative weights of the ultimate particles of bodies, is a subject, as * Subsequent experience renders this conjecture less probable. B4 far 24 Absorption of Gases by Water and other Liquids. far as I know, entirely new: I have lately been prosecuting this inquiry with remarkable success. The principle cannot be entered upon in this paper; but I shall just subjoin the results, as far as they appear to be pig ae by my expe- riments. Table of the relative Weights of the ultimate Particles of ' Gaseous and other Bodies. Hydrogen - - - - 1 Azote c - 4 - 4:2 Carbon 2 ~ - 4°3 Ammonia - - e + 522 Oxygen - - - - 55 Water . = a . 6°5 Phosphorus ~ = - 72 Phosphuretted oe - - 8°2 Nitrous gas - = a - 93 Ether - ~ = te 9°6 Gaseous oxide of carbon - - 9°8 Nitrous oxide - - -., 4a? Sulphur - = = = eels Nitric acid = - - = 15"2 Sulphuretted hydrogen = . - 1594 Carbonic acid $ - - 15°3 Alcohol = m= cl eres titan sia © = 1°9705. _. These experiments, which were frequently repeated, and always gave the same result, establish, therefore, completely the absorption of azotic gas in the act of respiration, and the active part which this gas performs. We understand, at the same time, more easily why the azotic gas, comparatively with other mephitic gases, is so little adverse and pernicious to our lungs. According to the experiments of Lavoisier and Secuin, animals supported Jife very well in a mixture of 15 parts of azotic gas with 1 of oxygen; although the same animals were suddenly suffocated in a mixture of 40 parts of oxygen gas, 45 of azotic gas, and 15 of carbonie acid gas, We understand, at least in some degree, the extraordinary, effects of the gaseous oxide of azote. We understand the transformation of chyle, being less animalized, less azotized in the lymphatic part of the blood, to be very much ani- malized and very much azotized by the act of respiration, &c. However, the quantity of azotic gas absorbed by a. single respiration is not very considerable; which agrees perfectly with the experiments of Davy, who, in nineteen respirations of a volume of 16} cubic inches, absorbed no more than 5:1 cubic inches of azotic gas. 11. To determine the quantity of carbonic acid gas pro- duced by the respiration of atmospheric air, 60 cubic inches were respired once during 10 or 12 seconds, and received over the mercury in the expiration. Lime water absorbed 4:68 in 100 parts. This experiment, several times repeated, gave the same result. The latter portion of expired air, transmitted frequently through lime water, exhibited a di- minution of 4°9 in 100 parts. 12, Twenty cubic inches, three times respired succes- sively during 10 seconds, showed no more than +3, of car- bonic acid gas. . wae-170 Sai inches were respired four times during 5Q seconds, and there was obtained 4°74; of carbonic gas. 14, 170 On the Respiration of Atmospheric Air. 57 14, 170 cubic inches were respired from a bladder eight: times in a minute. The lime water absorbed -833,. This quantity of carbonic acid produced by respiration gave a term of comparison to determine the quantity of de- composition of oxygen gas in the respiration of the same quantities of atmospheric air and of pure oxygen. The pre- ceding experiment (7.) had-denoted that the diminution of oxygen gas was more considerable than that of atmospheric air. According to this, one might expect, with the appear- ance of probability, that the production of carbonic acid gas should be also more considerable ; which was confirmed by direct experiments. 15. 170 cubic inches of oxygen gas obtained from man- ganese were respired four times during 50 seconds: the di- minution was 30 cubic inches. The a of carbonic acid which was produced amounted to -83%;. The atmo- spheric air, respired in the same manner, and under the same circumstances (13.), contained only .3;8; of carbonic acid. 16. Seventy cubic inches, respired from a bladder in the space of 50 seconds, even gave +5 of carbonic acid. Experiments on the Respiration of Gaseous Oxide of Azote. The gaseous oxide of azote was obtained, according to the process of Davy, from crystallized nitrate of ammonia. This jitrate of ammonia gives products very different in different temperatures. I undertook on this subject an important operation, which I submitted to the inspection of the Na-- tional Institute. I haye only to remark, by the way, that we obtain at the commencement oxygenated muriatic gas, if the nitrate of ammonia is not entirely free from muriatic acid; that at a temperature which does not ga beyond the 220th degree of the centigrade thermometer we obtain the gaseous oxide of azote in very great quantity, and very pure, and without a mixture of those white vapours which have the taste of mustard ; but at higher temperatures, and above all at a red heat, the gaseous oxide of azote is not disen- gaged, but there are formed nitrous gas and white vapours, quite 58 Experiments and Remarks on a Substance quite uncommon in the analysis of which I am at present engaged. To prevent all explosion, I constantly mix the nitrate of ammonia with very pure sand. To obtain the gaseous oxide of azote very pure, the distillation is performed in a sand bath, and the fire is managed with great care. When the whole succeeds well, the gas is so pure that one may respire it immediately. It has an agreeable taste, almost saccharo= vinous. If it is mixed with the white vapours produced by an excess of heat, it nmust be left a sufficient time to separate itself, After wwo or three hours it may be respired without danger. The effects which Davy has observed, and which Pictet hag described in so interesting a manner in his second letter (Bibl. Britannique, tome xvii, p..406.), have been perfectly, confirmed in my experiments. Many persons who have re= spired this gas have been intoxicated very quickly, and put, into a state of ecstasy very extraordinary and very agreeabie, Others have resisted its effects a little more ; and one indi- vidual was not at all affected by it. This state of intoxication has always passed without leaving a sensible relaxation. I am still continuing these experiments. It is not improbable that this gas may become a very important remedy for me- lancholic persons. I will not fail to communicate the whole series of experiments to the National Institute, ’ XU. Additional Experimenis and Remarks on an artificial Substance which possesses the principal characteristic Pro- perties of Tannin, By ‘CHartes Harcurrt, Esq. BF. RSS. mY [Continued from our jast volume; p- 326] § IV. 7. MADE scveral unsuccessful attempts to form the artificial substance by means of oxymuriatic acid; and it therefore appeared certain, that although a variety of the tanning matter could be produced by the action of sulphuric acid on resinous substances, yet the most effective agent was nitric possessing the Properties of Tannin, . 59 nitric acid, which readily formed it when applied to any sort of coal. But I nevertheless suspected, that possibly this substance, or something similar to it, might be produced without abso- lutely converting vegetable bodies into coal; for it seemed, as I have observed in my former paper, that this only served to separate the carbon in a great measure from the other elementary principles (excepting oxygen) which were com- bined with it in the original substance, and thus to expose it more completely to the effects of the nitric acid, as well as to prevent the formation of the varions acid products, which are so constantly afforded by the organized substances when thus treated. At first I had some thoughts of employing. touchwood in this experiment: but not being able immedi-~ ately to procure any, it occurred to me that indigo might probably answer the purpose; for from some experiments made by myself, as well as from those described by Berg- man*, I well knew that the proportion of carbon in this substance is very considerable. The following experiment was therefore made: 1. On one hundred grains of fine indigo which had been put into a long matrass, one ounce of nitric acid diluted with ‘an equal quantity of water was poured ; and as the action of the acid was almost immediate and extremely violent, an- other ounce of water was added. When the effervescence had nearly ssubsided, the vessel was placed in a sand-bath during several, days, until the whole of the liquid was evaporated. On the residuum, which was of a deep orange colour, three ounces of boiling distilled water were poured, by which a considerable part was dissolved. ; The colour of the solution was a most beautiful deep yel- low, and the bitter flavour of it surpassed in intensity that of any substance in my recollection; it was examined by the following reagents: Sulphate of iron produced a slight pale yellow precipitate. Nitrate of lime only rendered it a little turbid; after which * Analysis Chemica Pigmenti Indici. Opuscula Berg. tom. v.p. 56. a small 60 Experimenis and Remarks on a Substance a small portion of white powder subsided, which had the characters of oxalate of lime. Muriate of tin produccd a copious white precipitate, which afterwards changed toa yellowish-brown. Acetite of lead formed a very beautiful deep Jemon-co- lonted precipitate, which possibly may prove useful as a pigment. Ammonia rendered the colour much deeper; after which the liquor became turbid, and a large quantity of fine yellow spiculated crystals was deposited, which being dissolved ir water did not precipitate lime from its solutions. , The flavour of these crystals was very bitter, and T suspect them to be composed of ammonia combined with the bitter principle first noticed by Welther*. Lastly, when dissolved isinglass was added to the yellow solution of indigo, it immediately became very turbid, and a bright yellow substance was gradually deposited, and coated the sides of the glass jar with a tough elastic film, which was insoluble in boiling water, and possessed the characters of gelatine combined with tanning matter. By this experiment I therefore ascertained, that a variety of the artificial tanning substance could be formed without previously converting the vegetable body into coal; and I have since discovered, that although indigo more readily yields this substance than most of the other vegetable bodies, yet in fact, very few of these can be regarded as exceptions, when subjected to repeated digestion and distillation with nitric acid, 2.—A. In my former paper T have stated, that common resin, when treated with nitric acid, yielded a pale yellow solution with water, which did not precipitate gelatine, and that it was requisite to develop part of the carbon in the state of coal by sulphuric acid, before any of the tanning substance could be produced; but having again made some of these experiments, I repeated the abstraction of nitric acid several times, and then observed, that the solution of resin yn water acted upon gelatine similar to the solution of indigo * Thomson's System of Chemistry, 2d edit. vel. iv. p. 246, which ‘ ‘possessing ihe Properties of Tannin. 61 which bas been described, and formed a tough yellow pre- cipitate, which was insoluble in boiling water. With other reagents the effects were as follow : Sulphate of iron, after i@ hours, formed a slight yellow precipitate. Nitrate of lime did not produce any effect. Muriate of tin, after i2 hours, afforded a pale brown pre- cipitate. And acetite of lead immediately formed a very ahandaes precipitate of a yellowish white colour. I repeated this eapemment on common resin, and re- marked, that during each distillation nitrous gas was pro- duced, whilst the deieetia of the acid which came over was diminished: the cause therefore of the change in the pro~ perties of the resin seemed to me very evident, and I was induced to extend ihe experiments to various resinous and other substances; but as the process was unifermly the same, I shall only notice the principal effects. B. Stick lac, when separated from the twigs, and treated as above described, copiously precipitated gelatine. C. Balsam of Peru during the process afforded some . benzoic acid, and gelatine was precipitated by the aqueous solution. D. Benzoin also, after the sublimation of some benzoic acid, yielded a residuum, which with water formed a pale yellow solution of a very bitter favour. This solution with sulphate of iron afforded a shght pale “yellow precipitate. With nitrate of lime not any effect was produced. The solution with muriate of tin became turbid, and 2 small quantity of brownish-white precipitate subsided. Acetite of lead immediately produced a copious pale yel- low precipitate. And solution of isinglass formed a dense yellow precipi- tate, which was insoluble in boiling water. E. Balsam of Tolu, like balsam of Peru, and benzoin, afforded some benzoic acid; and the residuum being dis- solved in water was found to precipitate gelatine. F. Asthe results of the experiments-on dragon’s blood were 62 Experiments and Reniarks on a Substanve were somewhat remarkable, I shall here more particularly’ relate them. One hundred grains of pure dragon’s blood, reduced to powder, were digested in a long matrass with one ounce of strong nitric acid ; the colour immediately changed to deep yellow, much nitrous gas was evolved, and to abate the effervescence one ounce of water was added. The di- gestion was continued until a deep yellow dry mass re- mained; and the matrass being still kept in the sand-bath, a brilliant feather-like sublimate arose, which weighed rather more than six grains, and had the aspect, odour, and pro- perties of benzoic acid*. a os The residuum was of a brown colour, and with water formed a golden yellow-coloured solution, which by nitrate of lime was not affected. With sulphate of iron it afforded a brownish-yellow ‘pres cipitate. With muriate of tin the result was similar. With acetite of lead a lemon-coloured precipitate was produced. Gold was precipitated by it in the metallic state, whilst the glass vessel acquired a tinge of purple: And dissolved isinglass produced a deep yellow deposit, which was insoluble in boiling water. A portion of the same dragon’s blood was simply exposed to heat in the same matrass, but not any appearance of ben- zoic acid could be discovered. Iam therefore induced to ‘believe, that in the first experiment it was obtained as a pro- duct, and not as an educt: a fact which as yet has not been suspected. G. Gum ammoniac afforded a brownish yellow solution, the flavour of which was very bitter and astringent. By sulphate of iron, this solution only became of a darker colour, but did not form any precipitate. * According to these experiments, dragon’s blood ought to be arranged. with benzo:n and the balsams; but as the samples of this drug are not always precisely similar, it would be proper to examine every variety. That which was employed in my experiments, was a porous mass of a dark red, and was sent to me by Messrs. Allen and Howard, of Plough-court, in Lom- bard street. Nitrate possessing the Properties of Tannin. 63 Nitrate of lime rendered it turbid, and” produced a slight precipitate. Muriate of tin formed a copious yellow precipitate. Acetite of lead produced & similar effect : And gelatine yielded a bright vellow deposit, which was completely insoluble by boiling water. Hi. Asa feetida yielded a solution which also precipitated gelatine like the substances above described. I. Solutions of elemi, tacamahac, olibanum, sandarach, copaiba, mastich, myrrh, gamboge, and caoutchouc, were next examined ; but these, although they precipitated the metallic solutions, did not affect gelatine. It is possible, however, that they might have produced this effect, had they been subjected to a greater number of repetitions of the process. K. Sarcocol, in its natural state, as weil as the gum sepa- rated from it by water, when treated with nitric acid, did not precipitate gelatine ; but produced effects on the metallic so- lutions similar to the above-mentioned substancés. * L. Gum arabic afforded oxalic acid, but not any of the tanning matter. M. Tragacantti yielded an abundance of saclactic acid, of oxalic, and of malic acid, but not the smallest vestige of the artificial tanning substance. N. Manna, when treated with nitric acid in the way above described, afforded oxalic acid, part of which was sublimed in the neck of the vessel. The residuum with water formed a brown solution, which yielded a pale yellow precipitate with eulphate of iron. Muriate of tin produced a pale brown precipitate. Acetite of lead formed one of a brownish-white hue. Lime was copiously precipitated from the nitrate of lime in the state of oxalate; but not the smallest eflect was pro- duced on solution of isinglass. O. Liquorice however afforded a different result ; for al- though the solution after the process with nitric acid resem- bled in appearance that which was yielded by manna, yet the effects were not the same. Sulphate 64 Experiments and Remarks on a Substance Sulphate of iron, after twelve hours, peat a slight brown precipitate. Muriate of tin had a similar effect. Acetite of lead formed a brownish-red deposit. Nitrate of lime also occasioned a brown precipitate : And solution of isinglass rendered it very turbid, and pro- duced a yellowish-brown precipitate, which was insoluble in boiling water, and possessed all the other characters of gela- tine combined with the tanning substance. P. Guaiacum, the properties of which are so singular in many respects, afforded results (when treated with nitric acid in the manner which has been described) different from the resins, although its external and general characters seem to indicate that it appertains to those bodies. Nitric acid acted upon it with great vehemence, and speedily dissolved it. The eh ey which was afterwards obtained, was also found to be almost totally soluble in water, and the solution acted on the metallic salts like those which have already been noticed; but with gelatine it formed only avery slight precipitate, which was immediately dis- solved by boiling water; and the remainder of the solution being evaporated, yielded a very large quantity of crystal- lized oxalic acid; so that in this respect guaiacum was found to resemble the gums, and to be totally unlike the. resins*, § V. As many vegetable substances when roasted yield by de- coction-a liquid which in appearance much resembles the artificial tanning matter when dissolved in water, I roasied some of the common. dried peas, horse-beans, barley, and wheat flour, the decoctions of which however did not afford any precipitate by solution of isinglass. * The properties of guaiacum which have been described, as wellas those ‘which were previously known, appear to indicate, that it is a peculiar sub= stance of a nature distinct from the resins, balsams, and even the um resins. “So remarkable indeed is this substance, that an accurate series of experix ments on the whole of its properties may justly be placed amongst the chee mital desiderata. 4 Even . possessing the Properties of Tannin. 65 Even the decoction of coffee did not yield any precipitate by this method, until several hours had elapsed, and I found that the precipitate so formed was permanently soluble in boiling water. But to explain this, we must recollect, it is extremely probable, that some peculiar nicety is required in the roasting of such bodies before the tanning substance can be developed; and this seems to be corroborated by some experiments which I made on the decoction of a sort of coffee prepared from the chicorée (1 suppose endive) root, which was given me by Sir Joseph Banks ; for although this decoction did not afford an immediate precipitate with solution of gelatine, and although the precipitate was also apparently dissolved by boiling water, yet upon cooling, the same precipitate was reproduced in its original state. [am ~ therefore inclined to believe, that the tanning substance is really deyelojed in many of the vegetable bodies by heat, but that a certain degree of temperature, not very easy to deter- mine, is absolutely requisite for this purpose. Before I conclude this section, it may be proper to ob- serve, that when a small quantity of nitric acid was added to any of the above-mentioned decoctions, and when these had been subsequently evaporated to dryness, and afterwards dissolved in distilled water, they were converted into a tanning, substance perfectly similar to that which is produced by the action of nitric acid on the varieties of coal. § VI. In the preceding paper, a variety of the tanning substance was slightly noticed, which was formed by the action of sulphuric acid upon common resin, elemi, amber, &c. &c. and as an instance has occurred of the formation of the same substance from camphor, accompanied by circum- stances which tend to increase our knowledge of the proper- ties of the latter, I shall here describe this experiment. Experiment on Camphor with sulphuric Acid. The effects produced on camphor by sulphuric acid have been but'very superficially examined; for all that has hitherto been stated amounts to this, that camphor is dissolved by Vol. 24. No. 93. Feb. 1806. E sulphuric / 66 Experiments and Remarks on a Substance sulphuric acid, that a brown or reddish-brown solution is formed, and that the camphor is precipitated unchanged from this solution by water. These facts, however, only relate to acertain period of the operation ; for, if this be long continued, other effects are produced, which I shall now describe. A. To one hundred grains of pure camphor put into a small glass. alembic, one ounce of concentrated sulphuric acid was added. The camphorimmediately became yellow, and gradually dissolved, during which the acid progressively changed to brownish-red, and afterwards to brown. At this period scarcely any sulphureous acid was evolved, but in about one hour the liquid became blackish-brown ; much sulphureous acid gas was then produced, and conti- nued to increase during four hours, when the whole appeared like a thick black liquid, at which period not any odour or appearance of camphor could be perceived, but only that of the sulphureous acid. After two days, during which time the alembic had not been heated, there did not appear any alteration, unless that the production of sulphureous gas was much diminished. The alembic was then placed in 4 sand-bath moderately warm, by which more of the sul- phureous gas was obtained, but this also soon began to abate. After the lapse of two other days, I added gradually six ounces of cold water, by which the liquid was changed to reddish-brown, a considerable coagulum of the same colour subsided, the odour of sulphureous gas, which in some measure had still prevailed, was immediately annulled, and was succeeded by one which resembled a mixture of oils af lavender and peppermint. The whole was then subjected to gradual digtiftarton, during which the water came over strongly impregnated with the odour above mentioned, accompanied by a yel- lowish oil, which floated on the top of it, and which, as far as could be ascertained, amounted to about three grains. B. When the whole of the water was come over, there was again a slight production of sulphureous gas. I then added two ounces of water, which I drew off by distillation, bat did not obtain any of the vegetable essential oil which has possessing the Properties of Tannin. 67 has been mentioned, nor did the odour of it return. I there- fore continued the distillation until a dry blackish brown mass remained ; this was well washed with warm distilled water, by which, however, nothing was extracted ; but when two ounces of alcohol were digested on it during twenty- four hours, a very dark brown tincture was formed. The residuum was digested with two other ounces of al- cohol in like manner, and the process was repeated until the alcohol ceased to act. The residuum had now the appearance of a compact sort of coal in small fragments, it was then well dried, and after exposure to a low red heat ina close vessel weighed fifty- three grains. i: The different portions of the solution formed by alcohol were added together, and being distilled by means of a water- bath, a blackish brown substance was obtained; which had the appearance of a resin or gum with a slight odour of caro- mel, arid weighed 49 grains. The prodiiets therefore which were thus obtairied from 100 grains of camphor when treated with sulphuric acid, were, Grains, A. An essential oil which had an odour somewhat resembling a mixture of lavender and peppermint, about - - - - = - 3 B. A compact aud very hard sort of coal in small fragments - - - - - 53 C. Anda blackish brown substance of a resinous appearance = — = + 49 105 ne / From this statement it appears, that there was an increase in the weight amounting to five grdins, which I attribute ‘partly to oxygen united to the carbon, and partly to a portion of water so intimately combined with the last product, that it could not be expelled from it by heat without subjecting itto decomposition. The properties of this substance were as follows ; 1, [t was extremely brittle, had somewhat of the odour E 2 of 68 Substance possessing the Properties of Tannin. of caromel, the flavour was astringent, and it speedily dis-: solved in cold water, and formed with it a permanent dark brown solution. 2, This solution yielded very dark brown precipitates by the addition of sulphate of iron, acetite of lead, muriate of tin, and nitrate of lime. 3. Gold was copiously precipitated by it from its solution in the metallic state; and, 4. By solution of isinglass, the whole was completely pre- cipitated, so that, after three or four hours, a colourless water only remained. The precipitate was nearly black, and was insoluble in boiling water; from which property, as well as from the effect produced upon prepared skin by the solution, it was evident that the substance thus obtained from camphor was a variety of the artificial tanning matter, much resembling that which may be obtained from resinous bodies by means of sulphuric acid. But it must be observed that this sort of tanning substance seems to act less powerfully on skin than that which is prepared from carbonaceous sub- stances by nitric acid, and the precipitate which the former produces with solution of gelatine is more flocculent and less tenacious than that which in like manner is formed by the latter. It is however remarkable, that when a small quantity of nitric acid was added to the solution of the substance ob- tained from camphor, and when, after evaporating it to dryness, the residuum was dissolved in water, a reddish brown liquid was formed, which acted in every respect si- milar to the tanning substance obtained from the varieties of coal by nitric acid. [To be continued. ] XIII. On 4 i) Goes XIII. On the Oxides of Gold, Tin, and other Metals; with ints for extending their Uses in Dyeing. Communicated in a Letter to M. Bertuouurr ly M. Jouxn Micuarr HaussMAn*, I BELIEVE that I am as well founded as yourself {n admit- ting of intermediate terms of oxidation between the minimum nd maximum of several metallic substances. I shall, by- and-by, cite an example of the oxide of tin at the minimum precipitated from its muriatic solution, and redissolved by an excess of caustic potash; the alkaline metallic solution of which I have already mentioned in my observations upon the Adrianople red, inserted in the Annales de Chimiet, as well as in another memoir upon the coloured oxides of tin, given to the public in the Journal de Physique. In avoid- ing to dilute the muriatic solution of tin too much with water, and employing a solution of caustic potash very much concentrated, a considerable quantity of caloric disengages itself during the mixture of these two liquors: one portion _ of the tin precipitates itself in the metallic state, while the other remains in solution in a state of intermediate oxida- tion. This alkaline solution has so strong an aflinity for oxygen, that it changes into a gray colour the yellow oxide of gold fixed upon a piece of cotton by means of ammonia, while a similar yellow piece does not change its colour when allowed to soak in a pure liquor of caustic potash, The same change takes place upon plunging a smal] piece of cotton, which had been saturated with a solution of gold, well squeezed and dried, into an alkaline solution of tin. The same effect will follow if we pour into this alkaline so- lution a solution of gold diluted with water. The change of the yellow colour of the oxide of gold by the alkaline solution of tin is not the only proof of the in- termediate oxidation : this liquor, besides, possesses the pro- perty of extracting the blackish brown colour of the oxide of manganese fixed upon a piece of cotton by an alkaline pre- ! * From the Annales de Chimie, Mo. 166, } See Phil, Mag. vol. xii. and vol. xviii, “ ye ; © fe’ E 3 cypitat 70 On the Oxides of Gold, Tin, &c, cipitate. All these changes will take place more rapidly if, before performing the precipitation and re-solution by the liquor of caustic potash, the muriatic solution of tin is diluted with six or eight parts of water, In this case there will be no perceptible extrication of caloric, and there will be no precipitation of tin in a metallic state. This solution, the oxidation of which approaches to the term of minimum, preserves in general, without any precipitation of oxide, an aqueous transparency. Exposed for a long time to the at- mospheric air, it does not lose the property of changing the yellow oxide of gold into gray, and of extracting the blackish brown colour of the oxide of manganese fixed upon a piece of cotton. The oxide of manganese may present itself under different degrees of oxidation. If we impregnate a piece of cotton cloth with a transparent solution of sulphate of manganese, it will preserve its whiteness in drying: upon plunging the piece of cotton cloth thus impregnated into a solution of potash in a state of carbonate or of causticity, it will, when washed, be changed into a brown colour by the action of the atmospheric air. This colour will acquire a very dark hue, almost approaching to black, upon being allowed to remain some time in an alkaline oxymuriatic solution. This oxy- genated alkaline liquor will assume a purple colour, of a more or less transparent intensity, on leaving therein exposed, a longer or shorter time, some brown precipitate of manganese in place of a piece of cloth coloured with this metallic sub- stance, which therein dissolves itself, being oxidated by the fluid. In general, it is proper to attend to particular results in exposing all the metallic oxides to the action of this oxyge- nated muriatic alkaline liquor. This, perhaps, would be the means of giving them acid properties, and of proving at the same time more and more the gradual oxidation of most metals. Above all, it may be remarked of the white oxide of lead, which becomes gradually more and more coloured by a long exposure in this oxygenated liquor, in which it is necessary, nevertheless, to stir it often. The muriatic and nitro-muriatic solutions of tin, very much On the Oxides of Gold, Tin, ec. 71 much diluted in water, have an aqueous transparency when they are well made; but when mixed together, a fine colour, hike that of Malaga wine, is produced ; a circumstance which could never happen, unless the oxygen of the nitro-muriatic solution united with the muriatic solution of tin. If, ina similar mixture, we pour by little and little, stirring it at the same time, the solution of gold with a great excess of acid, and diluted in 130 to 160 parts of water, the imtensity of the colour of a similar mixture will increase more and more, and Jatterly present a very fine purple tincture, in which all sorts of stuffs may be dyed. By making the nitro- muriatic solution predominate, shades of peach flowers and lilies will be obtained ; and, on the contrary, shades more or Jess gray are obtained by making the muriatic solution of tin predo- minate. Care must be taken, however, not to employ the latter in too great- abundance, because, in powerfully extri+ cating the oxygen from the oxide of gold, it will deoxidate it too much, and precipitate it. The precipitate produced in this case is not entirely deprived of oxygen, which hinders it from gilding silver in the cold, like the ashes produced from the combustion of a piece of cloth impregnated with a solution of gold. The longer or shorter preservation of the golden tincture will depend entirely upon the proportions of the two different solutions of tin, more or less overcharged with acids, and the solution of gold, in which the acid ought always greatly to predominate. In exposing the purple tincture of gold, of the most perfect transparency, to a strong heat, it will decompose itsclf, and precipitate the colour known by the name of purple of Cassius, the beauty of which will depend more or Jess on the nitro-muriatic so- Jution of tin employed, which, mixed by itself with solution of gold, without the intervention of muriate of tin, produces no change of colour, and preserves itself a long time without forming any precipitate, if the mixture is not too much di- Juted with water. The purple tincture of gold is, properly, nothing else than the purple of Cassius, kept in solution by means of the oxygen of the nitro-muriatic solution of tin ; and there is every reason to believe that in the purple of Cassius the oxide of gold is in some measure combined with K4 the 72 On the Oxides of Gold, Tin, ec. the oxide of tin, which, giving up to it its oxygen during | its application to porcelain, binders, in my opinion, the gold from reducing itself and regaining its metallic lustre. I cannot subscribe to the opinion of Dr. Richter, of Berlin, who asserts, in a memoir which I have not read, to have mathematically demonstrated that the gold of a crimson co- Jour on porcelain is in the metallic state. The purple tincture of gold might, perhaps, be made use of to advantage in the dyeing of silks, although the price might be high: the colour obtained from it surpasses every other in solidity, because there is no combustion which can destroy it. It will be prudent, however, to agitate the stuffs along time in the tincture; and, to obtain shades more or less deep, it will be necessary to repeat the immersion of the stuffs more or less often, taking care to squeeze them well, and drying and shaking them between every immersion. The gradation of shades through which a mixture of the nitro-muriatic and muriatic solutions of tin passes, weakened by pouring into it, drop by drop, a solution of gold with a great excess of acid, and very much diluted with water, in- dicates, as I think, a gradual oxidation. An acetic solu- tion of iron, even, appears to ascertain the same; because, from a watery green, it acquires more and more a reddish yellow cast when exposed to the atmospheric air, or in con- tact with oxygen gas. I have made it appear, in a memoir upon the tincture of the alkaline mars of Stahl, that the sulphate of iron may also hyper-oxygenate itself, and lose the excess of oxygen by the action of light. In making a mixture of the concen- trated sulphuric acid and the nitric salution of iron, I ob- tained, after the evaporation of the nitric acid, and upon making the residue attract the humidity of the air, by al- enh it to rest a few months, crystals of byper- oxygenated siulphate of iron, which I could scarcely distinguish, owing to their whiteness, from sulphate of alumine ; but the action of light gradually yellowed the surface: their whiteness could be restored, however, by a slight washing. We may in the same manner procure a sulphate of iron hyper-oxy= genated, a little similar in whiteness, by precipitating the ui- 1 trate Partial Fusion of Metal ly the Electric Discharge. 73 trate of iron, and dissolving this precipitate (sweetened, and freed from the greater part of the water), by little and little, with sulphuric acid, which ought to be concentrated, in order to obtain, without evaporation, crystals of sulphate of hyper-oxygenated iron. This salt possesses an incompara- ble astringency. The operation of the transmission of oxygen appears to manifest itself the more upon pieces of linen simply dipped in acetate of iron, and maddered, since we are obliged, in order to bleach them completely, to expose them a long time in the field, if'we do not choose to make use of the artificial process of bleaching. The printed parts of these pieces of cloth are often weakened, and appear sometimes as if pierced with a sharp instrument, or burned with a concentrated acid: such a circumstance could not occur, except from the action of the oxygen of the coloured oxide of iron, oxygen being successively restored to this oxidable body by the atmospheric air. Minerals do not present the only substances which ox- idate gradually, and by intermediate terms. Indigo furnishes a proof that vegetables (and I may add also that animals) will produce similar results; for a so- lution of any kind of indigo (I except, however, the sulphate of indigo) may, in de-oxidating or in recovering oxygen, pass through all the degrees of the shades of blueish green, even to that of a very yellow clive, and yet preserve the sane quantity of indigo in solution. The beauty and soli- dity of the blues for dyeing, and of the blue for pencilling, depend much on the different degrees of oxidation. — XIV. On the partial Fusion of Metals by ihe Electric Discharge. By a Correspondent, To Mr. Tilloch, SIR, I TAKE the liberty of sending you some further experiments and observations on the partial fusion of thm plates of me- tal, &c. an account of which you was so kind as to insert in your 74 Partial Fusion of Metal by the Electric Discharge. your Magazine of March 1805, under the title of “ A new Electrical Phenomenon, communicated by a Correspon- dent.”” In these, experiments, which were chiefly made with a shilling, I could not reconcile the idea of a fusion taking place, the force employed being so very small: there is, however, no doubt but this is a fusion both on the part of the piece and the coating of the phial. Being induced to make these experiments with a greater degree of accuracy and observation, I began with a piece of money, as stated in my former paper: it is there said, * I sometimes observed a small hole in the coating where the piece was taken from :’’ I find that this is made at every dis- charge of the jar, whether the shilling 1s interposed or not. On examining this hole (which is just perceptible to the naked eye) with a microscope, I observed the coating cu- riously melted, very minute globules of the melted metal being scattered around it in every direction. Sometimes, when the jar is charged very highly, and the piece inter- - posed, several of these holes are made, in each of which there is the same appearance. A small white spot, encom- passed with a brown ring, is likewise observed on the shil- ling, which bears evident marks of fusion, thongh in a less degree than the tinfoil of the jar. On passing twelve successive discharges through a shil- ling, the surface became quite brown for about half an inch in length and two lines in breadth, This colour was not permanent, but easily rubbed off with the finger. The white spots, however, made at every discharge remained, and seemed to be indented on the surface. Jt is somewhat remarkable, that in al] these experiments the effect on that side of the piece which was next the coating of the jar was scarcely vi- sible, though the tinfoil was melted as before. This favours rather, I think, the idea of a single electric fluid. In cop- per, this effect seems to partake more of a calcination or ox- idation ; as the part where the discharge was made through was always white, though sull encompassed with the brown ring, From a number of trials it appears that this effect is scarcely, if at all, visible on thin plates of iron. Though I 4 haye On the Reproduction of Buds. 75 have subjected them to a greater force of electricity, yet I could never discover on them any marks of fusion, or that the metal was stained brown, as in the other experiments. It is very surprising that so small a quantity of accumu- lated electricity should operate so powerfully on a plate of metal, when it requires a very large battery to melt a small wire! Many electricians have turned their thoughts to the melting of wires, &c. by the electric battery, amongst whom I would notice Mr. A. Brooks, late of Norwich, who seems to have treated this subject with great perspicuity and exact- ness; but very few of them thought of making the discharge through plates of metal; which seems to open a wide field for observation and experiment. The insertion of the above in your publication will greatly oblige, SIT, Your obedient humble servant, > GR. - XV, On the Reproduction of Buds. By THomas ANDREW Knicut, Esq. F.R.S. Ina Letter to the Right Hon. Sir Josupu Bangs, K.B. P.R:8.* , MY DEAR SIR, Fivery tree in the ordinary course of its growth generates, in each season, those buds which expand in the succeeding spring; and the buds thus generated contain, in many in- stances, the whole of the leaves which appear in the follow- ing summer. But if these buds be destroyed during the winter or early part of the spring, other buds, in many spe- cies of trees, are generated, which in every respect perform the office of those which previously existed, except that they never afford fruit or blossoms. This reproduction of buds has not escaped the notice of naturalists; but it does not ap- pear to have been ascertained by them from which, amongst the various substances of the tree, the buds derive their origin. Du Hamel conceived that reproduced buds sprang from pre-organized germs : but the existence of such germs has * From the Transactions of the Royal Suciety for 1805, not, “76 On the Reproduction of Buds. not, in any instance, been proved ; and it is well known that the roots, and trunk, and branches, of many species of trees will, under proper management, afford buds from every part of their surfaces 3 and therefore, if this hypothesis be well founded, many millions of such germs must be annually generated in every large tree, not one of which, in the or- dinary course of nature, will come into action: and as na- ture, amidst all its exuberance, does not abound in useless productions, the opinions of this illustrious physiologist are, in this case, probably erroncous. ~ Other naturalists have supposed the buds, when repro- duced, to spring from the plexus of vessels which consti- tutes the internal bark ; and this opinion is, I believe, much entertained by modern botanists: it nevertheless appears to be unfounded, as the facts I shall .proceed ta state will evince. If the fruit-stalks of the seacale (cramle maritima) be cut off near the ground in the spring, the medullary substance, within that part of the stalk which remains attached to the root, decays; anda cup js thus formed, in which water .col- Jects in the succeeding winter. . The sides of this cup con- sist of a woody substance,. which in its texture and office, and mode of generation, agrees perfectly with the alburnum of trees ; and I conceive it to be as perfect alburnum as the white wood of the oak or elm: and from the interior part of this substance, within the cup, I have frequently observed new buds to be generated in the ensuing spring, It is suf- ficiently obvious that the buds in this case do not spring from the bark ; but it 1s not equally evident that they might not have sprung from some remains of the medulla. In the autumn of 1802 I discovered that the potatoe pos- sessed a similar power of reproducing its buds. Some plants of this species had been set, rather late in the preceding spring, in very dry ground, where, through want of mois- ture, they vegetated very feebly; and the portions of the old roots remained sound and entire till the succeeding autumn. Being then moistened by rain, many small tubers were ge- nerated on the surfaces made by the knife in dividing the | roots into cu tings ; 3 and the buds of these, in many instances, elongated On the Reproduction of Buds. 17 elongated into runners which gave existence to. other tubers, ; some of which I had the pleasure to send to you. ' - [have in a former paper remarked, that the potatoe con-. sists of four distinct substances, the epidermis, the true skin, the bark, and its internal substance, which from its mode of formation and subsequent office I have supposed to be alburnous: there is also in the young tubes a transpa- rent line through the centre, which is probably its medulla. The buds and runners sprang from the substance which I conceive to be the alburnum of the root, and neither from the central part of it, nor from the surface in contact with the bark. It must, however, be admitted, that the internal substance of the potatoe corresponds more nearly with our ideas of a medullary than of an-alburnous substance, and therefore this, with the preceding facts, is adduced to prove only that the reproduced buds of these plants are not gene- rated by the cortical substance of the root: and [I shall proceed to relate some experiments on the apple, and pear, and plum tree, which I conceive to prove that the reproduced buds of those plants do uot spring from the medulla. Having raised from seeds a very considerable number of plants of each of these species in 1802, [ partly disengaged them from the soil in the autumn, by digging round each plant, which was then raised about two inches above its former level. A part of the mould was then removed, and the plants were cut off about an inch below the points where the seed-leaves formerly grew; and a portion of the root, about an inch jong, without any bud upon it, remained exposed to the air and light. In the beginning of April I observed many small elevated points on the bark of these roots, and, removing the whole of the cortical substance, I found that the elevations were occasioned by small protuhe- ances on the surface of the alburnum. As the spring ad- vanced, many minute red points appeared to perforate the bark : these soon assumed the character of buds, and pro- duced shoots in every respect similar to those which would have sprung from the organized buds of the preceding year. Whether the buds thus reproduced derived any portion of their 78 On the Reproduction of Buds: their component parts from the bark or not, I shall not ver ture to decide; but I am much disposed to believe that, like those of the potatoe, they sprang from the alburnous sub- stance solely. © . The space, however, in the annual root, between the: medulla and the bark is very small; and therefore it may be contended that the buds in these instances may have originated from the medulla. I therefore thought it neces- sary to repeat similar experiments on the roots and trunks of old trees, and by these the buds were reproduced precisely in the same manner as the annual roots: and therefore, conceiving myself to have proved in a former memoir * that the substance which has been called the medullary pro- cess does not originate from the medulla, I must conclude that reproduced buds do not spring from that substance. I have remarked in a paper which you did me the honour to lay before the Royal Society in the commencement of the present year, that the alburnous tubes at their termination upwards invariably join the central vessels, and that these vessels, which appear to derive their origin from the albur- nous tubes, convey nutriment, and probably give existence to new buds and leaves. It is also evident, from the facility with which the rising sap is transferred from one side of a - wounded tree to the other, that the alburnous tubes possess lateral, as well as terminal, orifices: and it does not appear improbable, that the lateral as well as the terminal orifices of the alburnous tubes may possess the power to generate cen- tral vessels; which vessels evidently feed, if they do not give existence to, the reproduced buds and leaves. And therefore, as the preceding experiments appear to prove that the buds neither spring from the medulla nor the bark, I am much inclined to believe that they are generated by central vessels which spring from the lateral orifices of the albur- nous tubes. The practicability of propagating some plants from their leaves may seem to stand in opposition to this hypothesis; but the central vessel is always a component part of the leaf, and from it the bud and young plant pro- bably originate. * Phil. Trans. of 1803. . T expected ‘ On the Reproduction of Buds. tee T expected to discover in seeds a similar power to regene- rate their buds; for the cotyledons of these, though dissi- milar in organization, execute the office of the alburnum, and contain a similar reservoir of nutriment, and at once supply the place of the alburnum and the leaf. But no ex- periments which [ have yet been able to make, have been decisive, owing to the difficulty of ascertaining the number of buds previously existing within the seed. Few if any seeds, I have reason to believe, contain less than three buds, one only cf which, except in cases of accident, germinates ; and sore seeds appear to contain a much greater number. The seed of the peach appears to be provided with ten or twelve leaves, each of which probably covers the rudiment of a bud, and the seeds, like the buds of the horse-chestnut, . contain all the leaves and apparently all the buds of the suc- ceeding year: and I have never been able to satisfy myself that all the buds were eradicated without having destroyed the base of the plumule, in which the power of reproducing buds probably resides, if such power exists. Nature appears to have denied to annual and biennial plants (at least to those which have been the subjects of my experiments) the power which it has given to perennial plants to reproduce their buds; but nevertheless some bien- nials possess, under peculiar circumstances, a very singular resource, when all their buds have been destroyed. A tur- nip, bred between the English and Swedish variety, from which I had cut off the greater part of its fruit-stalks, and of which all the buds had been destroyed, remained some weeks in an apparently dormant state; after which the first seed in each pod germinated, and bursting the seed-vessel, Seemed to execute the office of a bud and leaves to the parent plant, during the short remaining term of its existence, when its preternatural foliage perished with it. Whether this property be possessed by other biennial plants in com- mon with the turnip or not, [ am not at present in posses- sion of facts to decide, not having made precisely the same experiment on any other plant. I wil] take this opportunity to correct an inference that I haye 80 On the Reproduction of Buds. have drawn in ‘a former paper*, which the facts (though quite correctly stated) do not, on subsequent repetition of the experiment, appear to justify. I have stated, that when a perpendicular shoot of the vine was inverted to a depend- ing position, and a portion of its bark between two circular incisions round the stem removed, much more new wood was generated on the lower lip of the wound, become upper- most by the inverted position of the branch, than on the opposite lip, which would not have happened had the branch continued to grow erect; and I have inferred that this effect was produced by sap which had descended by gravitation from the leaves above. But the branch was, as I have there stated, employed as a layer, and the matter which would have accumulated on the opposite lip of the wound had been employed in the formation of roots, a circumstance which at that time escaped my attention. The effects of gravitation on the motion of the descending sap, and consequent growth of plants, are, I am well satisfied, from a great variety of experiments, very great; but it will be very difficult to dis- cover any method by which the extent of its operation can be accurately ascertained, For the vessels which convey and impel the true sap, or fluid from which the new wood appears to be generated, pass immediately from the leaf-stalk towards the root; and though the motion of this fluid may be impeded by gravitation, and it be even again returned into the leaf, no portion of it, unless it had been extravasated, . could have descended to the part from which the bark was. taken off in the experiment I have described. I am not sen- sible that in the different papers which I have had the honour to address to you, I have drawn any other inference which the facts, on repetition of the experiments, do not appear capable of supporting. Tam, &c. Elton, > THomas ANDREW Knicnor. May 12, 1805. * Phil. Trans. of 1803. + Phil. Trans. of 1804. XVI. Pro- [a] XVI. Proceedings of Learned Societies. ROYAL SOCIETY OF LONDON, Fes. 6. The Right Honourable Sir Joseph Banks, Bart. President, in the chair. The reading of Mr. Hatchett’s in- teresting paper on artificial tannin was resumed. Effects of sulphuric acid on vegetables in converting them into coal. Resins distilled yield but from +03 to -05 grains coal ; but when treated with this acid from -30 to°60; with muriatic acid somewhat less. Gums, whether by distillation or di- gestion with acid, yielded nearly equal quantities of car- bon. The author, from his numerous and very decisive experiments, proceeded with great caution to offer a theory of the formation of pit-coal ; and his own discoveries have enabled him to adduce facts that seem to leave us without hope of ever attaining much more complete knowledge of the origin and formation of pit-coal than what he has mo- destly proposed. That all carbonaceous matter is of vege- table origin, has been generally allowed ; and Mr. Hatchett thinks that the means employed by nature for converting vegetables into carbon has been by slow digestion of great masses exposed to the action of sulphuric acid. To this end he admits that muriatic acid may also have contributed ; but from the much greater universality of sulphuric acid, sulphate of iron (pyrites), &c. in coals, and his synthetical experi- ments, which often gave 60 per cent. of carbon from vege- table matter by means of this acid, he thence concludes that sulphuric acid must have been the more cfficient if not the sole agent. Carbon thus formed js found in many parts without bitumen, such as in Kilkenny and Bovey toals, &c. The bitumen is also formed of the resinous parts of vegetables subjected to the slow action of sulphuric acid. Feb. 13. Mr. Hatchett admits that his efforts to form bitumen have not been completely successful, although there can be no doubt of its constituent principles. All synthetic experiments, he observes, are necessarily conducted too rapidly, ard on too small quantities, ever to imitate effectu- ally the process of nature. To the submarine composts or ~ Vol. 24. No. 93. Fel. 1806. F vegetable 82 Royal Societ y of London. vegetable solutions of certain philosophers he seems decidedly averse, and appears also willing to deny the agency of mu- riatic acid in the formation of coal. For this, however, he has not assigned any reason, although the almost invariable contiguity of lime to coal would tae to prove, that had any quantity of muriatic acid been present at the formation of ‘either, a new and very different substance must have heen produced, The few saline springs found in the vicinity of coal-mines, he considers as no exception to the general prin- ciple of the inefficiency of miuriatic acid; and the discoveries of Mr. Peel. may perhaps render the opinion of our author still more probable. Mr. Hatchett allows that animal matter imay have contributed to the formation of pit-coal; but de- ni¢gs that any fire could have been accessory. The great frequency, indeed, of numerous animal substances found in the limestone that is contiguous to.coal-strata, renders it difficult to deny that animal matter could not have been pre- sent at the original formation of coal. Mr. Hatchett con- cludes this very able paper with declaring the necessity of - adhering invariably to that rigid systematic order which we hinted at in a former report, and without which, he observes, that science can neither be extended nor applied to the pur- poses of civil society.. He also reeommends such researches to the attention of other chemists, as he has determined to decline them for the present, and hopes that his discoveries and numerous experiments may be usefully applied to the arts, and the important ceconomy of fuel, &c. The thanks of the Secicty were ordered to this philosopher, and we doubt not that he will also receive those of the civilized world. On the same evening a letter from Mr. Grifiths to che President was read, containing a brief account of a species of worm-shell found by him in a bank of clay on the coast of Sumatra, after the shock of an earthquake. Consider- able numbers of the same species are found in the surround- ing seas, in water from ouc to six fathoms deep, and vary in: length from three to five feet, and in diameter from three to nine inches. Que of the specimens procured by Mr. Grif; fifths measures above five feet, is taper, has two tentaculi, and EO British Institution.—Society of Antiquaries. 83 and in other respects is somewhat different from ihe figure given by Rhumphius. Not one of those shells could be pro- cured perfect in itself, but their figure may be correctly conceived from the different broken specimens. The body of the fish consisted of a gelatinous mass. The outside of the shell was white, the inside yellow, and its fracture strongly resembled stalactite. Feb. 20.' The introduction to a mathematical paper on * Impossible Quantities” was read,. but it is impossible that, we Can report it. A physiological paper, ona particular affection of the pro- state gland, was also announced, the reading of which was deferred till next meeting. BRITISH INSTITUTION FOR PROMOTING THE FINE ARTS. The gallery belonging to this laudable institution was opened on the 17th of the present month (February) for the exhibition and sale of the productions of the British artists ; and will continue open every day from 10 in the morning till 5 in the afternoon. It is but justice to say, that the dis- play of taste, talent, and genius, which even the first open= ing has exhibited, are highly creditable to the British school. Many of the picturcs possess the highest excellence, and all of them do honour to the individuals who have produced them. SOCIETY OF ANTIQUARIES. Feb. 6. Mr. Orde in the chair. Several curious historical notices were read on the character and office of the antient minstrels, or, as they were sometimes called, cytharists, in this country; from which it appeared that several females had assumed the character of wandering minstrels and dancers. Their loose manner of life soon rendered them ob- noxious to the laws, and they were at length suppressed as common rogues and vagrants ; but their music and dancing, we are happy to find, at no period, had any relation to the general licentiousness of persons of the like profession in every country on the continent. Feb. 13. The right honourable president, Earl of Leicester in the chair. Mr. Lysons furnished some extracts from Fe the 84 Royal Jennerian Society. the antient records of falconry, in the reign of Edward VI. The word mews, now improperly but generally applied to a pile of stables, was originally applied to a long range of build- ings appropriated to the mewing and breeding of falcons. An old painting, dated 1560, with the poetic inscription— * Rather deathe+Then false of faythe;” was exhibited by a baronet, under the impression of its being a portrait of lady Jane Grey ; but which might be more probably her mo~ ther, as se POH by the secretary, the Rev. Mr. Brand. This circumstance should teach amateurs not to be so ere dulous in purchasing old paintmegs. ROYAL JENNERIAN SOCIETY. At & special meeting of the board of directors, lately held at the central house of the society, No. 14, Salisbury-square, Fleet-street, the following report of the medical council, on the subject of vaccine inoculation, was laid before the board. REPORT. The medical council of the Royal Jennerian Society, having been informed that various eases had occurred, which excited prejudices against vaccine inoculation, and tended to check the progress of that important discovery in this kingdom; appointed a committee of twenty-five of their menfbers to inquire, not only into the nature and truth of such cases, but also into the evidence respecting instances of small-pox, alleged to have occurred twice in the same apa In consequence of this pebererieey the committee made diligent inquiry into the history of a number of cases, in Which it was sapposed that vacchiation had failed to prevent the small-pox, and also of such cases of small-pox as were stated to have happened ela to the natural or inoculated small-pox. © In the course of their examination the committee leatviett; that opinions “and assertions had been advanced and cit- culated, which charged the cow-pox with rendering patients liable to particular diseases, frightful in their appearance, and hitherto anknown; and judging such opinions to be. a connected Royai Jennerian Society. 85 _connected with the question as to the efficacy of the practice, they thought it incumbent upon them to examine also inte the validity of these injurious statements respecting yac- cination. After avery minute investigation of these subjects, the result of their inquiries has been submitted to the medical council; and from the report of the committee it appears : I.. That most of the cases, which have been brought for- ward as instances of the failure of vaccination to prevent the small-pox, and which have been the subjects/of public atten- tion and conversation, are cither wholly unfounded or grossly misrepresented. II. That some of the cases are now allowed, by the very persons who first related them, to have been erroneously stated. III. That the statements of such of those cases as are published, have, for the most part, been carefully investi- gated, ably discussed, andfully refuted, by diferent writers on the subject. IV. That notwithstanding the most incontestable proofs of such misrepresentations, a few medical men have per- sisted in repeatedly bringing the same unfounded and refuted _ reports and misrepresentations before the public ;_ thus per- versely and disingenuously Jabouring to excite prejudices against vaccination. -V. That in some printed accounts adverse to vaccination, in which the writers bad no authenticated facts to support the opinions they adyanced, nor any reasonable arguments to maintain them, the subject has been treated with indecent and disgusting levity; as if the good or evil of society were fit objects for sarcasm and ridicule. VI. That when the practice of vaccination was first in- troduced and recommended by Dr. Jenner, many persons, who had never seen the effects of the vaccine fluid on the human system, who were almost wholly unacquainted with the history of vaccination, the characteristic marks of the genuine vesicle, and the cautions necessary to be observed in the management of it, and were therefore incompetent to Fa decide 86 Royal Jennerian Society. decide whether patients were properly vaccinated or not, nevertheless ventured to inoculate for the cow-pox. VII. That many persons have been declared duly vacci- nated, when the operation was performed in a very negli- geut and unskilful manner, and when the inoculator did not -afterwards see the patients, and therefore could not ascertain whether infection had taken place or not; and that to this cause are cértainly to be attributed many of the cases ad- ‘duced in proof of the inefficacy of cow-pox. VIII. That seme cases have been brought before the committee, on which they could form no decisive opinion, from the want of necessary information as to the regularity of the preceding vaccination, or the reality of the pcos mi appearance of the small-pox. IX. That it is admitted by the committee, that. a few cases have been brought before them, of persons having the small-pox, who had apparently passed through the cow-pox in a regular way. X. That cases, supported by evidence equally strong, have been also brought before them, of persons who, after having once’ regularly passed through the small-pox, either by inoculation or natural infection, shade had that disease a second time. XI. That in many cases in which the small-pox has occurred a second time, after inoculation or the natural dis- ease, such recurrence has been particularly severe, and often fatal; whereas, when it has appeared to occur’after vacci- nation, the disease has generally been so mild, as to lose some of its characteristic marks, and even sometimes to render its existence doubtful. XIf. That it is a fact well ascertained, that, in some par- ticular states of certain constitutions, whether vaccine or variolons qwatter be employed, a local disease only will be excited by inoculation, the constitution remaining un- affected; yet that matter taken from such local vaccine or variolous pustule is capable of producing a general and per- fect disease, XUI. That if a person, bearing the strongest and most indubitable Royal Jennerian Society. 87 indubitable marks of having had the small-pox, be repeatedly. inoculated for that disease, a pustule may be produced, the matter of which will communicate tlie disease to those who have not been previously infected. XIV. That although it is dificult to determine precisely the number of exceptions to the practice, the medical coun cil are fully convinced that the failure of vaccination, as a preventive of the small-pox, is a very rare occurrence. XV. That of the immense number who have been vacci- nated in the army and navy, in different parts of the united kingdom, and in every quarter of the globe, scarcely any instances of such failure have been reported to the committee but those which are said to have occurred in the metropolis or its vicinity. XVI. That the medical sounicil are fully aad that in very many places in which the small-pox raged with ‘great violence, the disease has been speedily and effectually arrested in its progress, and im some populous cities nen exter- minated, by the practice.of vaccination. XVII. That the practice of inoculation for the small-pox; on its first introduction into this country, was opposed and very much retarded, in consequence of misrepresentations and arguments drawn from assumed facts,-and of mis¢ar- riages arisimg from the want of correct information, similar to those now brought forward against vaccination, so that nearly fifty years elapsed before small-pox inoculation was fully established. XVIII. That by a reference to the bills of mortality, it will appear that, to the unfortunate neglect of vaccination, and to the prejudices raised against it, we may ina great measure attribute the loss of nearly two thousand lives by the small-pox, in this metropolis alone, within the present year. XIX. That the few instances of failure, cither in the inoculation of the cow-pox, or of the small-pox, ought not to be considered as objections to either practice, but merely as deviations from the ordinary course of nature. XX. That if a comparison be made between the preserva- tive effects of vaccination, and thuse of inoculation for the Ir 4 smal]. 38 Royal Jennerian Society. small-pox, it would be necessary to take into account the greater number of persons who have been vaccinated within a given time; as it is probable that, within the last seven years, nearly as many persons have been inoculated. for the eow-pox as were ever inoculated for the small-pox since the practice was introduced into this kingdom. : XXI. That from all the facts which they have been able to collect, it appears to the medical council, that the cow- pox is generally mild and harmless in its effects; and that the few cases which have been alleged against this opinion may be fairly attributed to peculiarities of constitution. XXII. That many well-known cutaneous diseases, and some scrophulous complaints, have been represented as the effects of vaccine inoculation, when in fact they originated from other causes, and in many instances occurred long after vaccination ; and that such diseases are infinitely less frequent after vaccination, than after either the natural or inoculated small-pox. Having stated these facts, and made these observations, the medical council cannot conclude their report upon a subject so highly important and interesting to all classes of the community, without making this solemn deelaration : That, in their opinion, fasted on their own individual experience, and the information which they have been able to collect from that of others, mankind have already derived great and incalculable benefit from the discovery of vacci- nation; and that it is their full belief, that the sanguine ex- opciatitnin of advantage and security which have been formed: from the inoculation of the cow- pox, will be ultimately and, completely fulfilled. (Signed), Ed. Jenner, M.D. president. W. Blair. J.C. Lettsom, M.D. V.P. — Gil. Blane, M.D. John Ring, V. P. - Isaac Buxton, M.D. Joseph Adams, M.D, Wm. Chamberlaine. John Addington. John Clarke, M. D, C. R. Aikin. Astley Cooper. Wm. ‘Babington, M. D. Wm. Daniell Cordell. M. Baillie, M.D. Richard Croft, M.D. © Tho, Academy of Useful Sciences at Erfurt. 89 Tho. Denman, M.D. John Dimsdale, Henry Field. Edward Ford. Joseph Fox. Will. M. Fraser, M.D. William Gaitskell. Wm, Hamilton, M.D. John Hinzgeston. Everard Home. Robert Hooper, M. D. Joseph Hurlock. Wiliam Lewis. William Lister, M.D. Alex. Marcet, M.D. Joseph Hart Myers, M.D, James Parkinson. Thomas Paytherus. John Pearson. George Rees, M. D. John Gibbs Ridout. J. Squire, M.D. James Upton. J. Christian Wachsell. John Jones. Thomas Walshman, M, D. Thomas Key. Robert Willan, M.D. Francis Knight, Allen Williams. E. Leese. James Wilson, L. Leese. J. Yelloly, M.D. John Walker, January 2, 1806, Secretary to the council, ACADEMY OF USEFUL SCIENCES AT ERFURT. Professor Bernardi is returned to Erfurt from his five months tour through the Carinthian Alps. Notwithstand- ing the difficulties he had to encounter from. unfavourable weather and the operations of the war, he has no reasons ta be dissatisfied with the result of bis journey. He has made a number of new discoveries which he is about to publish. In an essay read before the academy, on the 2d of De- cember, he says: ‘* It surely cannot -be supposed that our country has been yet sufficiently examined. In the southern part of it, mm particular, there are many hidden treasures of science; and it is incontestably a great error in our country+ mien to travel into foreign countries, forgetting the treasures of which Germany has to boast.”” The first proof which the professor exhibited of this fact was by the communication of two kinds of the herb Speedwell or Fluellin, not yet hitherto sufficiently well described, and which nearly re- semble the Veronica spicata, The one he calls Veronica 5 cristala, go Academy of Useful Sciences at Erfurt.—Gottingen. cristata, and the other Veronica sternlergiana. The first, which he found in Hungary near the German frontiers, and on the mountains of Dornach not far from. Vienna, differs very little from the Veronica spicata in the form of the stalk and leaves, but much more in the blossoms and the stalk-of the flower. It carries its blossoms in a proper ear. ‘The folds of the flowers, which resemble a short pipe, are not so broad; they are rolled together to the very middle, and do not present a genuine pipe; so that the flower assumes a funnel-like appearance, and approaches very nearly in its stalk to that of the Veronica sibirica and virginica. In respect to other particulars it does not differ very much from the Veronica spicata, which is already accurately de- scribed. In the botanical system it has the following cha- racteristic—Ver. spica terminali, corollz subrotatz, laciniis postice convolutis, faleis oppositis—The second specimen Count Sternberg already remarked in Italy in the Sette commu- ni, and gave it the name of Ver. glabra. But as Ehrhardt had made use of this name to another kind of Veronica, Bernardi thought proper to name it after its discoverer. It principally grows at Krain, near Jauernberg, on the hills which surround the foot of Belsbiza. Its stalks and leaves are almost entirely hairless ; the first is very lank, and its longer-stalked blos- soms stand somewhat crowded together; it may be re- cognized by the following difference—V. racemo terminall, corollz rotate, laciniis patentibus, foliis oppositis, cauleque glabris.—Professor Bernardi has more clearly described the deubtful Speedwells or Fiuellins—V. vurticsefolia, latifolia, Teucrium, prostrata et pilosa, and has assigned to them pro- per descriptions. This essay of Professor Bernardi will ap- pear in the acts of the academy, a new volume of which will be immediately published. ' ‘ ACADEMY OF SCIENCES, GOTTINGEN. . . This‘academy has added the names of Chaptal and Cuvier; both members of the National Institute of France, to the list of their forcign associates. yidiee ; . XVIL. Iniel- C 91 ] XVII. Intelligence and Miscellaneous Articles. - PRODUCTION OF MURIATES BY THE GALVANIC DECOM- POSITION OF WATER. To Mr. Tilloch. SIR, Leicester, Feb. 15, 1806. T save the pleasure to inform you I have tried Mr. Peel’s experiments relative to the formation of muriat of soda and ° muriat of potash, which were in your Magazine in April and July last, and find them to be perfectly correct. Yours truly, &c. &c. A. B. Hortrenrz. BEET-ROOT SUGAR. A manufactory for this sugar has been established by a company of merchants in the neighbourhood of Moscow ; and the success of the establishment has proved, that from this vegetable a sugar is obtained which not only finds a ready market, but which, the consumers say, yields in no quality whatever to the sugar generally in use. A specimen has been presented to his majesty the empe- ror of Russia, who was pleased to express his high satis- faction with it. CURE FOR DROPSY. We haye already had occasion to.announce, that different people who had been afflicted with dropsy, had been per- fectly cured by means of Bohea tea. In the Greenock Advertiser we find the following instance of the efficacy of this remedy : A correspondent in Islay requests us to state, for the information of the public, that Donald Cameron, a herd upon the farm of Machry, in that island, was severely afflicted with a dropsy, which kept him bed-fast from July to November last ; but was finally cured by using a quarter of a pound of Bohea, drinking a strong intusion of it, and eating the leaves. In three days the immense quantity of water that was in his body disappeared, the tea having acted as a powerful diuretic; and he is now stout and hearty, 4 after 92 Cure for Deafness.—Fowil Skeleton. — Dance of Death. after being despaired of and given over by all of the faculty that saw him. CURE FOR DEAFNESS, : Petersburgh, 22d January. Demetri Simeonovitsch Sitnikoff, a merchant in Moscow, was for half a year deprived of the faculty of hearing, and all the remedies usually prescribed for that disease were used without effect. At last he had recourse to the following simple operation: After having filled his mouth with the smoke of tobacco, he closed it firmly, and also his nose, thereby foreing the smoke to find its way through the ears, The following morning he felt a crash, first in one ear, and then in the other, and from that moment his hearing has been completely restored.—Hamlurgh Carrespondenten, Fe~ bruary 8, FOSSIL SKELETON. At Sir Joseph Banks’s conyersationi on the 2d of February, —— Hawker, esq. of Dudbridge, Gloucestershire, exhi-~ hited complete drawings, and several of the bones of a large fossile animal similar to a crocodile, found in a solid stratum of limestone 20 feet thick. It was imbedded 15 feet below the surface of the stratum. The skeleton measures 101 feet in length, and all the parts are wonderfully perfect. The jaws which were exhibited contained the tecth in high pre- servation, and stil] covered with the enamel. One of them’ , which was broken had so exactly the fracture of what is called petrified wood, that it would have deceived the most acute mineralogist, and furnishes a strong ground for suspi- cion that many fossils generally held to be of vegetable are of animal origin. In the same stratum of limestone are found fany cornua ammonie, mussels, and other shells. HOLBEIN’S DANCE OF DEATH, It is wel] known that Basil in Switzerland was celebrated for Holbein’s celebrated picture of the Dance ef Death, which had undergone several repairs from time to time, and had been recently retouched, to the great satisfaction of all the connoisseurs. In the evening of the 6th of August last, hewever, a mob collected in Basil, and, accompanied by a | great Falling Bodies. —Russian Literature arid Embassies. 93° great number of women carrying lanthorns, broke’in upon the gallery inthe church+yard, which contained this master+ piece of antiquity, tore it from the walls, and ina few mua nutes succeeded in completely destroying it ! ; FALLING BODIES. Mr. Benzenberg, professor.of physic. and astronomy at Dusseldorf, has published an account of twenty-eight ex- periments made in the coal mines of Schebusch with balls well turned and polished. ‘They were made to fall from “a height ef 262 French feet. Ata medium they produced a deviation of five lines towards the east: the theory gives 4-6 lines. These experiments furnish an additional proof, if any were wanted, of the rotary motion of the earth. Ex-- periments made at Bologna by Mr. Guclielmini gaye nearly the same results. PROGRESS OF LITERATURE IN RUSSIA. In the year 1804, fifteen new journals were printed int Russia, and 145 new books were published the samie year at St. Petersburg and Moscow: among the latter were transla- tions into the Russian language of the following works-—_ Sterne’s Tristram Shandy; Rousseau’s Confessions, and his Eloisa; Hufeland’s Art of prolonging Human Life; Bar-: thelemy’s Travels of Anacharsis ; besides a variety of original, works in the Russian language. RUSSIAN EMBASSIES TO PEKIN AND JAPAN. Petersburgh, Jan. 13. Several persons who were appointed to travel with: the embassy to Pekin have returned from Irkuzk, and have al- ready arrived here. ‘The counsellor of state, Fosse, who accompanied the chamberlain Resanow on the embassy to Japan, has also arrived here from Kamtschatka. After-a stay of seven months, the embassy left Japan and returned to Kamtschatka in the Naveschda, a vessel commanded by captain. Krusenstiern. Chamberlain Resanow set out from thence to Kodiak, and the other possessions of the Russian American company, according to his instructions, after hav- ing dispatched counsellor Fosse here by the way of Ochozk. Captain Krusensteirn sailed with the rest of the embassy for : Canton, gt List of Patents for New Inventions. Canton, their original destination, whence, it 1s expected, they will return next August. As far as we learn, no acci- dent had befallen the embassy, all the members of which were in good health, The Naveschda left Kamtschatka in: the middle of June. LIST OF PATENTS FOR NEW INVENTIONS. To William Sampson, of Liverpool, in the county of Lancaster, wheelwright; for certain improvements in the application of power employed mechanically, especially as adapted to the use of cranks, and fly wheels or other con- trivances producing cquivalent or similar effect. Dated Fe- bruary 12, 1806. To John Phillips, of East Stonchouse, in the county of Devon, stonemason and sculptor; for improvements in the construction of tinder-boxes. Dated February 12. To John Phillips, of East Stonehouse, in the county of Devon, stonemason and sculptor; for a chain and apparatus for straight, square, and parallel stone and marble sawing ; which chain may be applied to other useful purposes. Dated February 12 To John Marshall, of Northwick, in the county palatine of Chester, salt proprietor; and John Naylor, of Hartford, in the same county, salt proprietor ; for a new and improved method or manner of manufacturing and making salt. Dated February 14. To Thomas Kentish, of Baker-strect, North, in the parish of Saint Marylebone, in the county of Middlesex, esq.; for certain improvements in the construction of machines or en- gines applicable to the moving, raising, or lowering of heavy bodies and weights of all kinds, Bike r upon land or on board of ships and vessels. Dated February 20. To John Woodhouse, of the parish of Heyford, in the county of Northampton, engincer ; for certain improvements relative to canals. Dated February 20. To John Jones the younger, of Birmingham, in the county of Warwick, tool-maker and die-sinker ; for improvements in the mode of manufacturing barrels for fire-arms. Dated February 20. , METEORO- Meteorology. 95 METEOROLOGY. Monthly recapitulation of meteorological observations made at the forest four miles east of the river Mississippi, in latitude 31° 28” north, and in longitude 91° 30” west of Greenwich, for the year 1800. By William Dunbar, esq. - ) ; Ps, : THERMOMETER. | BAROMETER. Rarn. *. ne 5 | | | | | | Year 1800. Greatest Height Least Height we mo 5 oo So | _ Om —— a | Deg. | Deg. | Deg. | Inches. | Inches. January | 6s | 213| 431 30-05 | 29°60 ‘February | 72 | 25 | 421!| 30-10 29°52 | (March | 78 | 28 | 584 30-00 | 29°38 | 29°78 | 1°53 } ? = wa ee —— ——_____|- —____ | ‘April | 85 | 44 | 663| 30-07 | 29°65 | 29°84 | 6°92 | ‘May | 903! 61 | 72 || 29-95 | 29°62 | 29°76 | 3°94 | June 96 61 | 79 | 29°99 | 29°61 | 29-80 | 1-26 | ee ie | ee a a ee : July 96 | 63 | 614 29°99 | 29°78 | 29°90 || 4°83 | | 96 | 70 | 82 | 29-99 | 29°71 | 29°86 | 0°35 eS - 90 | 59 | 761| 29°99 | 29°71 20°83 4°40 | 87 | 36 | 66 | 30°29 | 29°78 | 30°19 | 0:40 i| 79 | 92 | 56 | 30°43 | 29°91 | 30°13 0:03 75 | 12 | 474 644! 3 Mr. Dunbar’s general observations on each month say, The month of May is the most agreeably temperate, and one of the driest; but the present is an exception to the rule. METEORO-~ 36 Meteorology. METEOROLOGICAL TABLE; ‘By Mr. Carey, or THE STRAND, For February 1806. Thermometer. ore ‘AR Devs of the | 2} + |B g | Height of S38 Beith, 2 ‘eh s G = the Barom.| 3°28 Weather. = é ~ |e | Inches. Ca Be -) a A faci Jan. 27 39°| 34°} 29°10 n° Cloudy 28 36} 34} +10 4 |Cloudy 29 3 34 15 Oo [Snow 30 B44. B38. WS 5 |Cloudy 31 37 | 30 "54 lo {Fair Feb. 1 42] 31 "84 16 |Fair 2 BZ) .32 “gO oO. |Snow 3 35 | 31 "62 7 {Cloudy 4 374-35 "62 0 [Cloudy 5 53 | 47 64 18 {Fair 6 47 | 46 -70 |. g |Showery 7 53 | 46 60 24 |Fair 8 | 52 | 46 "80 20 (|Fair 9} 47 | 40 "59 o jRain 10; 48 | 39 “73 15 —|Fair i 47 | 41 "82 10. ‘|Fair 12 44 | 39 "84 26 _\Fair 13 44 | 32 69 15 |Cloudy 14 Al. | 36 *40 > o. |Rain 15) 42} 37 “56 .| o |Rain 16| < 44 | 37 "94 7 |Cloudy 17, 36 | 47} 33 | 30°00 [ a1 Bair 18) 42. {33 -20 15 |Cloudy 19 43 | 39 “23 15 |Cloudy 20) 3 | 40 | 29°95 10 |Cloudy 21) 50 | 45 "83 7 |Cloudy 22 52 } 40 61 10. .|Fair 23 50 | 44 “80 12 |Cloudy 24 55 } 48 | 30°20 22 |Fair 25 54 | 47 *22 15 |Cloudy “NW. B. The barometer’s height is taken at meen. er ET TIE XVIIL. On the Possibility of naturalizing the Cachemire Goat of India to the Climate of Europe: in a Letter from Dr. De Carro, of Vienna, to Professor Picrer, of Ge- neva™. Vienna, July 3, 1805. bee remember, sir, undoubtedly, the project which I communicated of profiting by the complaisance of nu- merous correspondents. whom I have in different parts of Asia, and of the obligations which they acknowledge they owe to me for having furnished them with the means of propagating vaccination through a great part of the East. You know that my principal aim was to direct their atten- tion to the alimentary plants of Asia, the culture of which might be useful in Europe. Of such plants I have conti- nually solicited the seeds, with instructions for the necessary culture, rélying at all timds in this search on the informa- tion of the learned Dr. Roxburgh, manager of the botanic garden at Calcutta. I have also had recourse to you, sir, in requesting your suggestions on those objects which might be particularly useful to our country. You have thought of mountain rice. I have asked it from my correspondents ; and, in spite of the small hopes of success which your expe- riments have hitherto afforded me, I shall still submit to your care and experiments the specimens of such articles as I receive from the East. You have, among other things, enjoined me to consider if means could be used to bring to Constantinople a pair of those famous goats of which the wool is manufactured into those beautiful and costly Cache- mire shawls, so much in fashion throughout Europe and Asia. Considering the difficulties of such an enterprise, it is proper to cite, perhaps, the very passage of your letter of the 21st of March 1805:-—‘* Do you believe it possible to bring to Constantinople a pair of shawl goats? The Enyvlish have not succeeded in naturalizing this Indian animal to their own climate. A single goat was brought to England, * From Bibliotheque Britannigue, vol. xxix. Vol..24. No. 94. March 1806. G but . 98 On the Cachemire Goat of Inaia. but died almost immediately on its arrival. The attempt, however, may have been made without suitable care. My experience in sheep makes me unwilling to believe in. the impossibility of naturalizing a breed to any cli- mate. But it is an enterprise for a prince: for the shawl goat must be brought from the mountains of Thibet, and there would be many difficulties to surmount in obtaining a specimen. It is a problem which I submit to you for solu- tion.’’. Judging, as you do, that the difficulty of bringing goats from Thibet would be in fact insurmountable, I set about obtaining information if there was no climate nearer Constantinople to which this animal was naturalized. This was my ebject im a note which | sent on the 4th of April last to Mr. Wallenbourgh, who passed many years at Constanti« nople when employed in the-Impetial legation, but now in thie state chancery at Vienna, and who is well skilled in the Janguages and commercial affairs of the East. He had the goodness to communicate to. me the answer which he re- éeived, and to allow me to: make what use I might please: éf it. ee Mr. Cogiasar de Sophialy to Mr. (Vailenbourgh. ig Although during my stay of some years at Bagdad F busied myself in collecting all possible information concern- ing the manufacture of Cachemire shawls, yet I was desirous, if possible, to obtain some further information from a Persian merchant lately arrived here, that I might answer the note I received from you. The animals whose fleece affords the Cachemire shawls are not goats, but sheep. There is a di- $tance of 305 conaks (days’ journeys) between the moun- tains where they are found, and Bagdad. To be sure of pre- sérying a couple of pairs of those sheep, it would be neces- §ary to make a purchase of twenty pairs for the journey, as- the change of climate, and the length of the way, would be yery dangerous to them. It would be necessary to send to a confidential person to-make this purchase, and to conduct the animals hither; and he could scarcely return in less than five years, owing to the mode of travelling, It is well known that these journeys. are made with carayans of ca- a . mels ; On the Cachemire Goat of India. 99 mels; and the same camels that leave this place do not go on to Bagdad, these caravans being bound only from one town to another; so that he is often obliged to wait on his journey till another caravah is ready to set off. The khans or chieftains of these countries are, also frequently at war with each other; and the traveller may be sometimes shut up six months, or a year, in some town, from which he dares not attempt to stir—Such are the reasons of the journey being so tedious. “*Tt is impossible to bring the sheep in question in any other way than by these caravans of camels, by putting a pair in panniers upon each camel. This would cost at least 1500 piastres for the hire of the camels; besides, at least, 1500 more, to pay the confidential person employed to purchase and convey them: and besides all this, it would be still ne- cessary to hire three or four persons to take charge of those animals during a long journey. “It is questionable, however, how far one could count on the fidelity of this description of people; for they are often tempted by the love of gain, instead of fulfilling their com- mission, to stop in those distant countries, where ene can only hear of them once a year, and speculate with the mo- ney which has been advanced to them. We have experi- enced this ourselves. Twelve years ago we intrusted 50,000 piastres to a factor who went to get shawls manufactured for us at Cachemire; and we are still waiting his return: in the mean time he is amusing himself with speculations at our expense. Thus, setting aside these inconveniences, it would be ne- cessary to calculate on an expense of more than 50,000 piastres, without the certainty, even if the object were attained, of saving a couple of pairs of the sheep. Their food is her- bage; but, as they have to pass through deserts, it would be necessary to have always sufficient quantities in store; and this would require still more camels for its carriage, which must, of course, augment the expense. ‘¢ If the person who. desires to have two or three pairs of these animals, wishes them as curiosities, he must risk 50,000 piastres ; but if it be for the purpose of multiplying G2 the 100 On the Cachemire Goat of India. the breed in Europe, and obtaining their fleece for the ma- nufacture of shawls like those of Cachemire, 1 doubt if be could succeed at all. ‘The change of climate would, at first, assuredly deteriorate the fleece. Besides, I am certain that it would be impossible to imitate the shawls of Cache- mire. Their goodness, their elasticity, the liveliness of their colours, are owing to the water of the river which passes through the city } and the same shawls, when washed in the same river fifteen miles further down, do not acquire the same good qualities: the difference is incredibly striking both to the feeling and sight. It would be therefore use- - less to bestow so much expense on this object. ‘© Such, sir, is the best information I can send you on the subject of your inquiries; Iam sorry Ican send you none more favourable. With respect, I am yours, &c. ‘¢ (Signed) CoG1AsAR DE SOPHIALY *.”’ All these details justify the opinion you have expressed of the great difficulty of the enterprise. It is not, however, such as a government, or a rich company, could not at- tempt. If such information could be turned to use, I should rejoice to have communicated it. You have stated, on the authority of some travellers, in some passages of the Bibliotheque Britannique, that the animal in question is a goat: according to the preceding letter it is asheep. Which isin the right? If it be Mr, Cogiasar de Sophialy, it is for you, sir, a great encouragement to continue your efforts for the amelioration of wools, and the imitation of the Cache- mire shawls. Observations of M. Pictet on the preceding Letter. , It is in the valleys and on the mountains of Great Thibet that the animal lives which furnishes materials for the ma- nufacture of Cachemire shawls. The distance is thirty days’ journey eastward from Cachemire to the place where they are found. (See Forster’s Travels in Cachemire.) We are entitled to call this animal by the name of goat, on the au- * Mr. Cogiasar de Sophialy is, according to Mr. De Wallenbourgh, ¢ne of the greatest merchants of Constantinople, an Armenian by birth, and the most skilful person in commercial matters to whom he could have addressed himself. ‘ thority On the Cachemire Coat of India. 101 thority of a passage taken from Turner’s s Relation of an Embassy to Thibet, published in 1800. The English ambassador had passed the Bootan and approached Teshoo Lamboo, the residence of the Jama, in the 28th degree of north Jatitude, before he saw any herds of those precious animals. ** The shaw! goats feed in numerous herds on the short and scanty herbage which scarcely covers those elevated places. This animal is, perhaps, the most beautiful of all those that compose the numerous family of the goat kind. Their colour varies much. Some are black, some white, some blueish, and others of a tint a little lighter than that of a young fawn. This goat has straight Horns, and is shorter in height than the smallest English ‘sheep. The matter em- ployed for the fabrication of shaw!s 1s a fine down which hes close to the skin. A Jong coarse hair covers this down, and serves to preserve its softness.” “ Forster, who carefully examined the valley of Cachemire, calls the matter of which these shawls are made wool. But he never saw the animal; and this expression no more proves its being the production of a sheep, than the term vigonia wool proves that the vigon is not of the goat kind. We know that the camel, the paca, the glama, the vigon, the, goat of Tauris, and one of the varieties of the goats of Sy- ria, yicld, under the long and coarse hair, adown more or less fine. It is true that there are races of sheep, such as those of Shetland, those of Iceland, and some parts of Siberia and Tartary, which have in like manner a fine and soft down under their rough wool. Thus, the animal of Thibet which produces the precious matter of the shawls may, perhaps, be asheep. By its dimensions it should belong rather to the sheep than the goat race, and it would not be astonishing that travellers should have made some mistake. Samuel Turner inspires confidence in his observations respecting natural history. He appears accurate in all the details re- lating to his mission. [He describes distinctly all the ani- mals of those high regions, and, in particular, the sheep of the country. The maaner in which he speaks of the flocks ef shawl goats leaves no room to doubt that he has examined G3 those 102 On the Cachemire Goat of India: those animals minutely. The word goat, which the English, who are best acquainted with those countries, have given the animal, is a strong indication that it is not a sheep, since they would have called them shawl sheep if it had shown the characters belonging to that race. The important point, however, is not its being a goat or a sheep, but whether it can be transported and naturalized to the climate of Europe. When we gave our correspondent, half in joke, half in earnest, the problem to solve, whether, a pair of those goats could be brought to Constantinople, we thought of the possibility of bringing them from the moun- tains of Lesser Thibet, near the country of Cachemire, and where the analogy of climate seems to indicate that they could live equally well. From the mountains of Lesser Thibet the river Giluma runs into the Caspian sea. The navigation of this river from Badacian to Sellizure is 400 leagues ; and the navigation of the Caspian, from Sellizure to Feorabath or to Terki, is about 200 leagues. From thence would remain the passage by land to Trebisond on the Black sea, or by the route to the mouth of this river, which, as 1s well known, formerly served for transporting merchandize from India. The letter of our friend’s correspondent gives, perhaps, an exaggerated idea of the real difficulties of transporting this animal; but the greatest difficulties might still occur in the proper regimen for their preservation in Europe. Thibet is the highest country of the old continent, and the airis uncom-~ monly dry during the season which is not properly the rainy season, 7.e. from October to June or July. The herbage of the pastures grows brown and dry, so as almost to crum- ble to powder when touched. It is this dried grass, very scanty in quantity, but apparently containing much esculent Substance in smal} volume, which is the sole nourishment of the shaw] goats. Could the animal subsist without a si- inilar nourishment? Would it he possible to procure the same grass in some parts of the Pyrennees, or the Alps? Is it not necessary for the animal to have a far southern cli- mate, and a soil extremely dry? If it could live in another climate, would it retain the down which preserves it from fs : the On the Theory of mixed Gases. 103 the cold? or would this down preserve its softness, its fine- ness, its strength and elasticity, which constitute its value? As to the secret virtue of the river which runs by Cache- mire, and which it loses further down, it may perhaps he of that kind of virtue which was attributed exclusively to the little river of the Gobelins. In all countries, the people who have brought any process of art to perfection are interested in throwing a mystery over the operations to which they owe their success. {f this idea of obtaining the shawl goats to Europe be not chimerical, it is for France to realize it, since it possesses the greatest variety of climates.— Our readers will judge by this specimen of the benevolent activity of Dr. De arro, whose success in propagating vaccination has only increased his zeal for the advancement of useful knowledge, on XIX. An Essay on the Theory of mixed Gases, and the State of Water in he viciutic ia By Mr. Joun Govcu*. Four essays appear in the fifth volume of the Memoirs of the Literary and Philosophical Society of Manchester, which contain many new ideas relating to the constitution of mixed gases, and the state of water in the atmosphere. The design of these papers is evidently intended to remove certain diffi- culties which must strike every man of scicnce who happens to peruse M. de Luc’s theory of atmospherical vapour. ‘This attempt has the double recommendation of ingenuity and novelty; but the leading opinions of the system, even in its present form, are liable to several objections, which I am going to point out, being generously invited to under- take the task by the author himself. My doubts relative to the subject arise partly froni mathematical considerations, and in part from the evidence of experiment. Certain objections of the first class dispose me to conclude, that an atmosphere con- structed on Mr. Dalton’s plan will appear upon examination to be repugnant to the principles of the mechanical philo- sophy; and a direct appeal to experiment has moreover con- * From Manchester Transactions, secoud series, yol.i. G4 vinced 104 On the Theory of mixed Gases. vinced me that well established facts contradict the essential points of the theory. ark To begin with the objections of the furmer class: I am ready to admit the existence of a fluid mixture,’ such as we find described at page 543, in the fifth volume of the Man- chester Memoirs, with this reservation, that the concession is made merely for the purpose of showing such a combina- tion to be incompatible with the usual course of things for a moment; which being demonstrated, the inutility of the fundamental hypothesis will follow, as a necessary conse- quence. To give a concise view of Mr. Dalton’s general notion of the subject, we are to suppose a number of di- stinct gases to be confined in a space common to them all ; which space may be circumscribed by the concave surface of a vessel, or the compressing power of an external fluid: besides this, we must imagine the constituent particles of . each individual gas to be actuated by a mutual repulsion, while at the same time they remain perfectly indifferent to the particles which compose the other fluids that are con- fined in the common space: in short, we are to conceive that the particles of each gas act upon those of their own kind in the manner of elastic bodies, but that they obey the laws of inelastic bodies as often as they interfere with cor- puscles of a different denomination. After premising the preceding particulars, we may conceive a certain arrange- ment of the elementary parts of a fluid mixture, in which the adjustment of the whole shall be of a description which will form, from particles of any one denomination, a homo- geneous fluid possessing its own separate equilibrium ; con- sequently each gas will exist as an independent being, and exercise the functions of its elasticity just as if all the other fluids were withdrawn from the common space. This sys- tematic arrangement in an assemblage of gaseous substances cannot be maintained unless one particular method of dis- posiug its component parts be observed, which consists in that distribution of the elements which will produce a sepa< rate. equilibrium in the fluid composed by the elementary corpuscles of each denomination; consequently, the equi- librium in question cannot take place unless the necessary disposition On the Theory of mixed Gases. 105 disposition of the heterogeneous particles be first established ; so that the former requisite of the theory is entirely dependent on the latter. After having acquired a distinct idea of a fluid mixture, composed of gases possessing separate equili- bria, we come in the next place to investigate the mechani- cal properties of such a compound ; in the prosecution of which inquiry the comparative densities of the constituent fluids must be first determined in a horizontal plane, the situation of which is given in the common space, Let the figure PMINKYV (Plate I. fig. 2.*) represent this space, in which MV NK isthe given plane. Now since every point of this plane may be supposed to be at an equal distance from the earth’s centre, the density of every homogeneous gas supported by it will be the same in all parts of it. Let the con- stituent fluids be denominated A and B; also let C denote the compound ; morcover let the densities of A and B, at P, be p and g; let PX and XY be two equal evanescent parts. of the line PV. Now, seeing the pressure acuung upon an elastic fluid is as the density of it, the fluxionary increments of p and q are as these quantities; but the densities of A and B, in the point X, are equal to the sums of pand gq united to their increments respectively: let these sums be called e and f; then eis to f as pis to g, by composition of pro- portion: in like manner we find the density of A at Y to be to that of B at the same point ase isto f; i. ¢. as pis to g; thence it follows, that the fluxionary increments of the two densities have universally the given ratio of p to q; consequently the contemporary fluents, or the densities them- sélyes, have the same given ratio ; now what has been proved of the two gases A and B may be extended to any other number, viz. the ratios of their densities on the same hori- zontal plane will be given. The ratio of A, B, &c. being found to be constant, we can proceed to investigate the proportions of the quantities of matter contained in these fluids. Let D and d be the densities of A and B in the plane MK NV; also let W and w be the quantities of matter of each kind contained in the yariable space PMK NV; call PV a, and the area of the * Given in our ‘ast number. plane 106 On the Theory of mixed Gases. plane MKNV y: now the fluxion of the space PMKNV is expressed by y into the fluxion of #; moreover the quan- tities of matter in two solids are in the complicate ratios of their magnitudes and densities, or in’ that of the densities only, if their magnitudes be equal; therefore the fluxion of W is to that of w as D is to d, because the fluxionary mag- nitude is common both to W andw; but-D isto d as p to g, a constant ratio; consequently fluxion of W is to fluxion of was p is to q; therefore W has to w the same given ratios that is, the matter in A is to the matter in B as p isto q. {n the next place let R and r be the distances of the centres of gravity of A and B, from the point P, taken in the line PI: then R into the fluxion of W is equal to the pro- duct of D, Y, x, and the fluxion of x, from a well known theorem in mechanics; for the same reason r into the fluxion of w is equal to the product of d, y, 2, and fluxion #; hence R into fluxion of W is to 7 into fluxion of w as Dis to d3; bat Dis to d as fluxion of W is to fluxion w; therefore R and 7 are-equal; consequently the centres of A and B coin- _¢ide, and the point of their coincidence is also the centre of the system C. Thus it appears, that when the compo- nent gases of a fluid mixture possess separate equilibria, their densities are every where in a given ratio, and they have a common centre of gravity: the converse of which is equally true, viz. if their densities be not every where in a given ratio, and if they have not a common centre of gravity, they do not possess separate equilibria. Tt is necessary to observe in this stage of the inquiry, that though we admit the particles of A and B to be inelastic in relation to each other, the concession must be strictly con- fined to the particles themselyes; for the gases which are composed of them are elastic bodies; they therefore receive and communicate motion according to the laws which are peculiar to bodies of this description. The foregomg pro- perties of a fluid mixture, which has been supposed to he duly adjusted, are now to be used in the examination of the fundamental proposition of the new theory intended to ex- plain the constitution of the atmosphere, According to this proposition, if two gases come into contact the particles of which On the Theory of mined Gases. 107 which are perfectly inelastic in respect of each other, the particles of A meeting with no repulsion from those of B further than that repulsion, which as obstacles in the way they may exert, would instantly recede from each other as far as possible in their circumstatices, and consequently ar- range themselves just as in a void space. The preceding are the words of the author of the theory; and it is readily granted that the particles of such a heterogeneous mixture would recede from each other as. far as circumstances will permit; the present subject of inquiry, then, brings the dis- pute to this issue—Can that arrangement take place amongst the particles of two or more gases, which will make their eentres of gravity coincide in one point? For the separate equilibria of the fluids which enter into the constitution of the compound, will not be established until this arrangement be perfectly formed. The completion of this process being essential to the new theory, the effect of it has been, per- haps, too hastily inferred in the fourth proposition of Mr. Dalton’s first essay ; for I am sorry to observe that the in- ference is not supported by demonstration drawn from the doctrine of mechanics. It is the business of the. present essay to supply what has becn omitted, and to investigate the consequences which must arise from the collision of two heterogeneous gases differing in their specific gravities.. ' The existence of the fluid mixture, required by the theory, has been granted already for the sake of argument; and in order to continue the inquiry it must be remarked at pre- sent, that the necessary internal arrangement of the com- pound C, is liable to be disturbed perpetually by accidents resulting from the course of things; to which course the author of the theory undoubtedly wishes to accommodate his ideas. The preceding assertion may be exemplified in a manner which is familiar, and may be applied with ease to natural phenomena: let us suppose, then, an additional quantity of the gas A to be thrown into the pneumatic ap- paratus containing the compound C, which was in a state of proper adjustment previous to this event. No one will ima gine that this fresh matter can diffuse itself through the mass of C with the same expedition that the electric fluid shows in 108 On the Theory of mixed Gases. in expanding along a conductor: this supposition is contra- dicted by various appearances, from which the following one is selected »—agitation is known to accelerate the union of oxygen and nitrous gas. The quantity of A then, which has been newly admitied, will remain at first unmixed with B; but it will act immediately with a repulsive force upon kindred particles diffused through the compound C. This new modification of A will not preserve the density of ats parts every where in a constant ratio to the density of the corresponding parts of B; and this change will disjoin the centres of gravity of A and B, which has ken proved above. But when these points are placed apart, the separate equi- libria of the fluids cease to exist, which has also been de- monstrated before: therefore A and B begin to aci and re- act mutually; which circumstance disturbs the necessary adjustment of C, and forces it to assume another character. It has also been proved in a former paragraph, that the two fluids will act upon each other in the manner of elastic bodies, even when the heterogeneous particles are supposed to be mutually inelastic ; consequently A and B will begin to obey the law of their specific gravities as soon as their centres of gravity are separated by introducing into the space occupied by C, a fresh quantity of A or B: in consequence of this alteration the centre of gravity of the heavier fluid will begin to descend, while that of the lighter moves upwards. When once the centres of two gases are placed apart, their separa- tion will become permanent; because, when at a distance, they are urged in opposite directions by a force resulting from the difference of the specific weights of the two fluids ; and this contrariety of efforts must continue so long as the two centres are disjoined; consequently this opposition of force must be lasting, seeing nothing can put an end to it but an union, which it will always prevent. Nor can the mutual repulsion of the constituent particles of each gas, considered apart, in any manner promote the junction of the centres of gravity of the two fluids, because the action and re-action of a number of bodies amongst themselves do not alter the state of their common centre of gravity, whe- ther it be at rest or in motion: so that A and B are under 4 the On the Theory of mixed Gases. 109 the necessity of observing the law of their specific gravities, just as if the kindred particles of each fluid were actuated by no reciprocal repulsion nor any other cause ‘of re-action. The doctrine of gases, which are mutually inelastic, is ren- dered indefensible by the preceding arguments; for the hy- pothesis is thereby exposed to a difficulty which, the author of the theory justly remarks, makes a mixture of mutually repulsive gases of different specific gravities an improbable conjecture ; so that his own objection ultimately discounte- nances the leading opinions of that theory which it induced him to adopt in particular. At the same time philosophers are convinced that the atmosphere is a compound of gases possessing various degrees of specific weight ; they moreover know that different chemical agents perpetually disturb the equilibrium of the compound, as some of them constantly absorb while others unfold the gases of which it is com- posed. The preceding facts are certain; consequently the heterogeneous elements of the atmosphere must be united by a common tie, which may be denominated a species of affinity, at least while our knowledge of the subject remains in its present imperfect state. The transparency of the great body of air surrounding the earth, also affords a strong argu-~ ment for the chemical union of its component fluids, and at the same time discountenances the idea of the compound being a mechanical mixture of any description whatever ; for when a number of diaphanous bodies of different specific gravities are mixed together, they form an aggregate which is opaque ; but the union of the substances by fusion renders the mass transparent in many instances. Now, as the at- — mosphere is diaphanous, we are obliged, by the principles of sound argument, to consider it in the ligkt of a com- pound, the ingredients of which are united by a chemical . tie. Whatever may be the condition of the elastic fluids which enter into the composition of common air, one thing is certain, from a preceding paragraph of this essay, namely, no one of them can maintain a separate equilibrium as long as it makes an individual of the aggregate ; consequently each particle of the compound must be urged by a force re- sulting 110 On the Theory of mixed Gases. sulting from the general action of the mass, not by a pres= sure occasioned by a particular member of it. On this account it is impossible for the aqueous part of common air to preserve the character of a gas at low tempe~ ratures, because steam cannot support 30 inches of mercury unless it is heated to 212 degrees of Fahrenheit’s thermo- metef: were it then practicable to mix vapour of a less heat with atmospherical air, the spring of the gases would reduce itin an instant to the state of a liquid; so that the difficulty which renders De Luc’s theory objectionable in its orginal form, is not removed in reality by the present modification of it. : The theory of mixed gases has been found to be indefensi- ble on the principles of the mechanical philosophy; and I suspect that part of it which relates to the separate existence of vapour in the atmosphere, will prove equally unfortunate when brought to the test of experiment. Mr. Dalton, in all probability, supposed he had done all that the confirma- tion of this theory required, by inventing the doctrine of separate equilibria; for nothing more has been offered in support of his opinions, particularly of that relating to the existence of uncombined vapour pervading the atmosphere, unless the statement of the following experiment, with his explanation of it, may be referred to this head. If two par- eels of dry air, which are equal in bulk, density, and tem- perature, be confined by equal columns of mercury, in two tubes of equal bores, one of which is wet and the other dry, the air, which is thus exposed to water, will expand more than that which is kept dry, provided the corresponding augmentations of their temperatures be equal; which phe- nomenon is thus explained on the principles of the theory : The vapour that arises from the sides of the wet tube, pos- sesses a spring of its own; therefore it takes off part of the weight of the mercury from the air, and thereby leaves it to expand itself, so as to re-adjust the equilibrium. According to this explanation, if / and g represent the lengths of the columns of dry and moist air at any temperature; and if ¢ denote the length of a column of mercury, equal in weicht 8 to On the Theory of mixed Gases. 111 to the pressure that confines the contents of the tubes; and if f be put for the spring of vapour of the same temperature Cc measured by a column of mercury, we have g = Fi from ct—_— which we also Bet, C= — the last expression affords us > TT fo) an opportunity of comparing the preceding explanation, and therefore the theory itself, with facts; for, according to the experiments of Mr. Schmidt, 1000 parts of dry air, at 32 degrees of Fahrenheit, will expand to 1087‘11 parts, by being raised to 59 degrees, in contact with water; call this number g; according to the same author, 1000 parts of dry air at 32 degrees will expand to 1053°61 parts, by being heated to 59 degrees in a dry tube: let this number be 5 then g — / = 33°50: but f, or the spring of vapour. at 59 degrees, is 507, according to Mr. Dalton; then fy = 551, 164; hence c = 16°15 inches; which expresses the height of the barometer, together with the column of mercury con- tained in the tube. If the temperature be stated at 95 de- grees, € will amount to little more than eight inches: now it is highly improbable that Mr. Schmidt imade his experi- ments when the barometer stood at a height indicated by either of these numbers. This application of the theory te practice affords a presumptive evidence that. the principles of it are not altogether just, supposing the experiments of Mr. Dalton and Mr. Schmidt tobe correct ; but a positive proof of a want of accuracy in these principles may be ob- tained by introducing a small change intvu the manner of conducting the experiment made with moist air. This al- teration consists ‘in discarding the stopple of mercury, and substituting the simple pressure of the .atmosphere in the room of it ;° because, when this substance, which is impene- trable. to Steam, has been removed, the redundant vapour will, according ‘to the theory, flow into the atmosphere, thereby Jeaving the moist air of the tube to follow the law of ‘exparision observed: by dry ‘air. ‘With a view to find whether this’ be «the case or ot, I filled a bottle with run- ning water.of the temperature of 59 degrees, which, when carefully poured out again, weighed 7794 grains. ‘The bot- 0) tle, 112 On the Theory of mixed Gases. tle, having a dew left sticking to the sides of it, was placed in water at the temperature of 126 degrees: the mouth, which remained about an inch above the surface, was co- vered with my hand, care being taken to remove it fre- quently for an instant to permit the vapour and expanding airto escape. After keeping it in this situation about two minutes, I secured the mouth in the manner described above, and inverted it in a quantity of the same water, where it was reduced to 59 degrees ; in consequence of which it took up L622 grains of water, leaving a space equivalent to 6172 grains. If the experiment be now inverted, 6172 parts of air will occupy the space of 7794 such parts when its tem- perature is raised from 59 to 126 degrees; which is nearly double the expansion of dry air in like circumstances. For, according to Mr. Schmidt’s experiments, 1000 parts of dry air of 59 degrees will become equal to 1133-03 such parts, by being heated to 126 degrees; therefore, by the rule of proportion, if 1000 parts give an expansion of 1133°03 such parts, 6172 parts give only 820: but the difference of 7794 and 6172 is 1622, which is nearly the double of 820. The preceding experiment, and others which I have made of the same kind, demonstrate that moist air expands more than dry air under like circumstances, and the fact subverts the notion of uncombined elastic vapour mixing with the atmo- sphere. The accuracy of the fact may be disputed; the doubt, however, is removed by repeating the experiment : but so long as my statement, remains uncontradicted, the consequences of it to the theory in question cannot be con- troverted by argument: for if elastic vapour mix with the air, it does more than merely enter the pores of this fluid ; for, according to my experiment, it enlarges these pores at low temperatures, which we know to be nnpossible, unless the heat of the compound arises to 212 degrees. Those who are convinced of the superior expansion of moist air, will readily apply the principle to certain interesting phenomena, in particular to the origin of tornadoes in hot countries, and the variation of the barometer in temperate climates. Mr. Barrow, an intelligent traveller in South Africa, ob- serves, that the atmosphere in Caffraria is sametimes heated to On the Theory of mixed Gases. 113 to 102 or 104 degrees: this is succeeded by local thunder storms, attended with heavy falls of rain and hail, as well as violent hurricanes. Ido not pretend to, assign the refrige- rating cause, or the agent that produces precipitation in this case; I only have to observe, that the portion of air must luse much of its elasticity, which is suddenly cooled to 70 or 72 degrees, and at the same time parts with the water it held in solution. This partial diminution of spring will destroy the equilibrium of the adjacent parts of the atmo- sphere, and may be supposed to produce the tornadoes of the tropical regions. The same cause probably gives rise to the fluctuations of the barometer in milder climates; for, though the changes of temperature are less in the milder than in the hottest parts of the globe, the agents that pre- cipitate the water of the atmosphere appear to act on a more extensive scale, and through a longer duration, in the former situations than they do in the latter. Wet weather is neither momentary nor local in Europe; provinces, and even king- doms, are deluged with rain for wecks together. The air,. which discharges such an abundance of water, will lose part of its spring, according to Mr. Schmidt’s experiments, even when it suffers no change of temperature: now it is evident that the equilibrium cannot be restored in an instant, be- cause the diminished elasticity must be augmented in this case by currents of air coming from remote places. The diminution of spring in the atmosphere is shown by the fall of the barometer, and the subsequent ascent of the mer- cury indicates the arrival of the restorative currents. Ac- cording to this explanation the barometer will rise slowly but gradually in the centre of the rainy district, while the motions of it will be more rapid and less regular towards the verge of the storm. High winds will also prevail in wet seasons, which will blow towards the parts where the elastic force of the air is least; that is, where the rains are most abundant.—I know not what claim to originality is due to the foregoing hints towards the theory of the barometer ; they have, however, the merit of being a natural consequence of an established fact; I mean the great dilatation of air satu- rated with moisture, which must undergo a proportionate contraction when deéprived of water. Vol, 24, No, ga. March 1806. H XX. An f W4-] KX. An experimental Inquiry into the Nature of Gravelly and Calculous Concretions in the Human Subject; and the Effects of Alkaline and Acid Substances on them, in and out of the Body. By THomas Ecan, M.D. M.R.LA. (Concluded from p. 36.] Experiment X1. As children are such frequent sufferers, Mr. Richards sug- gested the propriety of ascertaining whether the alkaline in- fluence might be weakened by the addition of sugar. Qne- half of a calculus, of the uric acid kind, weighing 1854 grains, extracted by my friend Mr. Richard Dease, and (though under the most unpromising circumstances) with a dexterity and success not to be exceeded by his late father, was suspended in a lixivium consisting of eight ounces of distilled water and twenty drops of weak agua kali puri (partly aérated), and scarce imparting an alkaline taste. To this were added thirty-six grains of sugar, which were found adequate to sweeten it sufficiently. After remaining forty-eight hours in a temperature varying from 55 to near 100 degrees, or a medium one of 74 degrees, being dried and weighed, it was found to lose ten grains three quarters. The addition, then, of saccharine matter cannot diminish, but may add to the alkaline energy. Experiment XII. Ten grains of very pure crystallized carbonate of potash were dissolved in four ounces of distilled water. In this filtered lixivium was suspended a fragment of calculus, of the uric acid kind, weighing seventy-two grains and a quar- ter, for forty-eight hours, on a sand-heat, varying from 50 to 100 degrees (for the fire was not kept up during the night). Being taken out, dried, and weighed, it was found to have lost seven grains and a quarter. The solution had a yellowish green colour, different from the light yellow tinge of the pure alkaline ones. It also lost its taste, but without becoming siveet. A quantity of flocculent animal matter was separated, and the dissolved uric acid was, for as the -» On Gravelly and Calculous Concretions. NS ‘the greater part, again precipitated, upon the mixture cool- ing, to the temperature of the “ig bagihe Experiment XIII. ‘The crystallized carbonate of potash, lal anctally. pre-| scribed in the proportion of one drdchm to four ounces of water; in a similar mixture was suspended an entire cal- culus, of a very compact, rough, and gritty appearance; weighing forty grains and a quarter. After remaining forty- eight hours in the above temperature, it was taken out, dried, and weighed, and found to have lost three grains three quar- ters. The solution here more highly coloured than in the for= mer! some spontaneous precipitation; and an immediate one, on the addition of a few drops of weak marine acid. We then find the vegetable alkali in the fullest state of saturation, with carbonic acid, that we can procure it, in the solid form, acting powerfully on these concretions, when assisted by degrees of temperature even much inferior to that of the human body. : Now, as to the mineral alkali, nature presents us with similar, nay, more extraordinary results, in the mild mi- neral alkaline impregnation of the waters of Carlsbad, in Bohemia. Here are several springs, varying in temperature from 114 degrees to that of the Brudel at 165 degrees. According to Elliot, they contain, in the gallon, of aérated lime 36 grains; muriate of soda 48; aérated soda 102; vi- triolated soda 6 drachms; some minute proportion of iron, and a considerable carbonic acid impregnation. But Klap- roth rates the proportion of mineral alkali still higher. Of the lithontriptic effects of these waters, Springfield gives us a very surprising account indeed: founded, how- ever, upon numerous experiments, instituted upon the spot, by the immersion of many calculi in the sources themselves ; where they were either entirely dissolved, or acted upon with an energy that must appear incredible, if we did not consider the nature of the menstruum, its high temperature, and con- stant renewal by the flowing of the stream. Nay, the urine of patients who used these waters for a few days was found to possess powerful lithontriptic effects, as appeared by the He immersion 116 On Gravelly and Calculous Concretions. immersion of many calculi in it. For an account of these highly interesting experiments, too numerous for msertion here, I must beg I@ave to refer to his Treatise De Preroga- tiva Thermarum Carolinarum, in dissolvendo Calculo Vesice, pre Aqua Calcis vive. From these experiments, as well as the highly. beneficial effects of these waters, taken internally, by the numerous ealeulous and gravelly patients who frequent Carlsbad, he establishes their superiority over the different alkaline and other remedies hitherto in use, not excepting Whyte’s oyster-shell lime water. Now, the lime in these being car- bonated, and only kept in solution by their highly aérated state, we can be at no loss, in those days, to attribute their superior agency to the alkaline impregnation, assisted by so high a temperature. Klaproth affirms, that a person who drinks these waters, in the usual quantity, for twenty-six days, takes of mild mineral alkali 3913 grains, or 8 ounces i drachm and 13 grains; which amounts to two drachms and a half per day, besides the other saline ingredients, Doctors Rutty and Smyth, who gave us a valuable extract from this publication, in the Memoirs of the Medical and Philosophical Society of this city, (now in the library of the Royal Irish Academy, but which, we have sincerely to regret, were never published, and are now discontinued,) conclude their account by the following query: ‘* May not some al- kaline lixivium be contrived by art, that would possess si- tilar effects with these waters?’? And has not this partly taken place in the instance of our soda waters? But may we not make a nearer approximation by a solution of the above specified proportion of mineral alkali in the relative quantity of water, with.the addition or omission of the car- bonic acid, and the other saline ingredients, as may be thought proper, afterwards heating, however, each separate dose to 160 degrees ? We find, then, the alkaline carbonates, in the great labo- ratory of nature, as well as in-our experiments, exerting con~ siderable sclvent powers upon these animal concretions con- trary to what has been hitherto supposed. Experiment On Gravelly and Calculous Concretions. 417 Experiment XIV. Into a filtered solution of ten grains of salt of tartar, in four ounces of distilled water, were introduced two fragments of calculi, weighing seventy-four grains and a quarter, The mixture was set aside for forty-cight hours in a cool room; temperature varying frou 47 degrees at night, to 55 degrees in the day. After twelve hours it began to be coloured, and continued to be more so, until the temperature fell to 51 degrees, when a precipitation took place, and continued during the night; so that it appeared to deposit at the tem- perature of 47 degrees, what was taken up at degrees some- what exceeding 51°. These fragments, on being taken out, dried, and weighed, were found to have lost three grains and three quarters ; the laminze disposed to crack, and the strata to separate and crumble. This weak lixivium, then, ex- erted much energy, even in a very low temperature. Experiment XV. A fragment of calculus, weighing seventeen grains three quarters, was immersed in a lixivium of similar strength 5 but now exposed to a temperature varying from 51 degrees at night to about 95 degrees in the day. After forty-eight hours, it was found to lose five grains and a half: a prodi- , gious quantity, when we consider the small surface pre- sented by this fragment, weighing only seventeen grains three quarters.! The solution, upon cooling, became turbid as before, and precipitated a large proportion of the dissolved uric acid, Experiment XVI. id A fragment of calculus, weighing forty grains three quar- ters, was immersed in four ounces of soda water for forty- eight hours, and exposed to a temperature varying irom 55 to about 100 degrees. Its loss amounted to one grain. A repctition of this experiment afforded nearly the same re- sult; and demonstrates, that though the soda, in this super- carbonated state, still exerts some energy on concretions of the uric acid kind, yet it is but feeble ; and that these waters appear more capable of preventing their formation than efs : i 3." fecting - 118 On Gravelly and Calculous Concretions. fecting their sclution, when they once acquire the aggregate. state. The same fragment, in a similar quantity of soda water, in the temperature of from 50 to 55 degrees only, sustained no loss, after forty-eight hours. And here we have another proof of the necessity of seriously attending to the degree of temperature in all researches of this kind. But it may be observed, as to the internal use of alkaline substances in particular, that their effects must be consi- derably weakened upon their immediate admixture with the. urine; as the smal] quantity that can be conveyed there must, in the first place, neutralize the uncombined phos- phoric acid in all urine, the benzoic in children’s, and de- compose the ammoniacal and magnesian phosphates in that of every period of life. It must be acknowledged its efficacy is partly counteracted by these circumstances, which should never be overlooked, and always taken imto account in prac- tical application. Referring to Fourcroy’s instructive essay on this subject, Memoirs of the National Institute, and Connoissances Chimiques, let us here once more appeal to the test of experiment. Experiment XVII. A fragment of calculus, weighing eighteen grains one, quarter, of the uric acid kind, was suspended, for forty- eight hours, in an alkaline lixivium, consisting of four ounces and a half of recent urine, and twenty drops of a very weak, and partly aérated, caustic lixivium ; medium temperature about 74 degrees. On being taken out, and dried, it was found to have lost one grain three quarters; a considerable quantity from so small a specimen. To the filtered solution were added a few drops of dilute marine acid, which; after a few minutes, precipitated a reddish ery- stalline matter in a triple proportion of what generally oe. curs in the natural state of urine. From the above experiments, therefore, it appears no longer doubtful; first, that pure lime, even in the small proportion bpoeiied in lime water, and the pure alkalies, in an extreme state of dilution, in temperatures even some- what inferior to those of the human system, exert an active solvent power on calculi of the uric acid kind ; secondly, that the On Gravelly and Caleulous Concretions. 119 the alkaline carbonates, under similar circumstances, are possessed of similar powers, though in an inferior degree : and thirdly, that, by our having ascertained this point, we have removed a long established error, substituted a disco- very highly interesting to animal chemistry, and likely to be productive of a more enlightened and successful Rraeie in the treatment of these diseases. In these expectations we shall appear to be the better founded, when it is considered, that, for want of entire spe- cimens (preserved here like the oriental bezoars of old), we were obliged to operate upon fragments presenting small surfaces only to our solvents: that these last were never renewed during the course of the experiments, which would not have occurred in their application in the form of injec- tions; as they should, in that case, be so often repeated, and act, of course, with renewed energy: that, either taken internally, or used in form of injection, the smallest propor- tion of alkaline matter, in a great state of dilution, assisted by the human temperature, answers our purpose; and that the temperature in our experiments was never permanent, and. might be rated at the medium one of 74 degrees. ‘ Having now fulfilled the second object of this essay, I would no longer presume to trespass on the indulgence of the academy, if I were not actuated by the sanguine bope of turning the attention of my surgical friends to the humane consideration of obviating, as much as possible, the most dangerous of operations by the prudent application of a few safe solvents injected’ into the bladder. How far they may succeed with calculi of the uric acid kind, may be already conjectured from the preceding experiments ; but with those of the next most frequent occurrence there is much less difi- culty to encounter, and every reason to hope for a speedy and safe result. The ammoniaco-magnesian phosphate is partly soluble in water, highly so in the carbonic acid (as we have already seen) ; and, consequently, more so in the weakest possible acid impregnations that can be devised ; nothing more being necessary than the addition of as many drops only of weak muriatic acid as will scarce impart an acid taste. But as precept should, im every instance, be as gs ae ‘ “much 120 On Gravelly and Calculous Concretions. much as possible assisted by experiment, I shall, for the encourageinent of the young practitioner, exhibit a few on this very soluble species the more willingly, as he has no assistance to expect from his professional books ; these sub- jects being only treated of in Philosophical Transactions, Memoirs of the National Institute, anda few other foreign chemical publications, if we except Whyte’s Treatise on Lime Water, to which we would willingly refer him. Experiment XVIII. An entire calculus, of a reddish, gritty appearance, exter- nally, proved to consist of ammoniaco-magnesian phos- phate, weighing forty-six grains one quarter, was suspended, for forty-eight hours, in a mixture consisting of four ounces of distilled water and ten drops of weak marine acid. After being taken out, and dried, it was found to have lost six grains three quarters. The mixture was whitish, lost its acid taste, and precipitated, on the addition of a few drops of fixed alka, the ammoniaco-magnesian phosphate, under that beautiful crystalline form so accurately described by Dr. Wollaston. ; We may readily conceive how much-more the loss would have amounted to in this case, in the short space of forty- eight hours, if the menstruum had been frequently repeated under the regular influence of human temperature. Experiment XIX. A fragment of the same species with the above, weighing twelve grains, was immersed, for forty-eight hours, in three ounces of distilled water, without addition: temperature from 60 to near 100 degrees. After being taken out, and dried, it was found to have lost one grain three quarters, became so friable as to crumble, and the solution to preci- pitate with a few drops of pure ammonia. This species of calculus, therefore, is soluble in water, at temperatures even inferior to that of the human. [It is unnecessary I should enter into a further detail of experiments made upon calculi of the mixed kind, having the uric acid, phosphate of am- monia, and sometimes, though rarely, phosphate of lime, intermixed On Gravelly and Calculous Concretions. 121 intermixed in their strata. Suffice it to say, that the very dilute marine acid speedily takes up the earthy phosphates, leaves the laminz of the uric-acid bare and distinct, ready to crumble, and of easy solution in the weakest alkaline lixs ivia, and still more so in lime water :—a most important consideration in a practical point of view. It would be trespassing too much on the already tried indulgence of the academy, to go further into the detail of the circumstances necessary to be attended to, and ac- quainted with, to ensure success in the application of these principles. These are already tolerably well detailed in the Connvissances Chimiques. To the gentlemen professors in the school of surgery it more particularly belongs; and from the zeal and talents now in full activity there, what may not be expected? Created only the other day, bya Cleghorn, (a name as deservedly as universally revered ;) fostered, afterwards, by the anxious care and talents of Mr, Dease; we find it already arrived at a state of perfect matu- rity, and holding out to the student advantages no where to be rivalled, if iniduall equalled: and that nothing may be wanting to a complete medical as well as surgical education, establishing a chair of botany, supported by the acknow-~ ledged abilities of Dr. Wade, both as a botanist and teacher. From the above experiments and observations we may pre- sume to draw the following conclusions : That acids, and acescent drinks of all kinds, give rise to gravelly and calculous affections, by causing a separation and precipitation of the native uric acid of urine within the body. That all acids, vegetable or mineral, nay, the native phosphoric acid of urine, in excess, are equally productive of this effect; the tartaric, perhaps, somewhat more so. That, on the other hand, we find lime, both the fixed al- kalies, pure as well as aérated, (even in the smallest proe portions,) serviceable in these disorders, by uniting with, and keeping in solution, ‘this acid substance. That they also, in the smallest proportions, and diluted state, exert strong solvent powers on this acid in its aggregate form of calculus, provided their action be favoured by degrees of temperature approaching to the human. That, under the same 122 On Gravelly and Calculous Coneretions. same circumstance, contrary to what was generally sup- posed, the carbonated, sub-carbonated, nay, the super-car~ bonated, exert similar influence, though in an inferior de- gree. That lime, even in the small proportion it presents itself to us in lime water, is a most active and safe solvent of calculi of the uric acid kind, and its various combinations ; as has been long since ascertained by Whyte. That, weight for weight, it exceeds even the caustic alkali im any state of dilution that the latter can be applied to the living body. That, finding four ounces of lime water, containing only two grains three quarters, take up, or detach, seven grains three quarters from a very compact calculus, we may be led to suppose this may arise from its action on the agglutt- nating medium, its affinity to, and energy on, animal matter being so well known; and, if so, may we not expect some- thing from its power on the mulberry calculus, our most formidable enemy? For, though it cannot touch the oxalate of lime, it may the cementing medium, with which it pe- culiarly abounds. For the application of these established facts to useful purposes, I must refer to my surgical friends, being all now possessed of the necessary degree of chemical acquirement ; and I am happy to find this career already entered on by my friend Mr. Crampton, who has favoured us with an analysis of a pulmonary calculus in the Philosophical Transactions, and from whose professional as well as scientific talents we have every thing to expect in fulfilling (even on this occa- sion) his duties as a teacher. Having now endeavoured to accomplish the chief object of this essay, which was, to establish experimentally a more clear and comprehensive view of the nature of these mala- dies, and the remedies employed to combat them, than we hitherto possessed, I should not have trespassed further on the time of the academy, were it not properly suggested, by my friend Dr. Clarke, that it would be of importance to ascertain how far the facts and notions, brought forward in it, may stand confirmed or contradicted by the result of our practical application of them in Simpson’s Hospital; an establishment affording the best and most extensive field of observation, On.Gravelly and Calculous Concretions. 1293 observation, of this kind, of any in Europe, that of Lune- ville, perhaps, excepted, The benefit of this charity exteuds equally to the blind and gouty. In the year 1795 I found it to contain thirty- two of the latter; and since that period thirty-four have been admitted: in all, sixty-six gouty patients. Of these, the greater number have either complained of gravel, or passed it without any previous or concomitant inconve- nience: a circumstance which I had every day occasion to observe, whilst attending to the state of gouty urine. Among the blind and gouty, however, we may count about twenty- two as spccifically more afflicted, having occasionally com- plained of marked and distinct symptoms of this disorder. Of these, we find sixteen among the gouty, and six only among the blind. Now, as the severity of gout is uni- formly diminished, nay, in many instances, the disease en- tirely removed, by a residence of a few years only in the house, we must expect to find the same take place with re- spect to gravel, to which it is so strongly and nearly con- nected. And this singular alleviation of both diseases we can only attribute to the influence of temperance, and the manner of living, very opposite to that of their former ha- bits. The diet in our house consists of bread and milk for breakfast and supper; beef, or mutton, with table beer, for dinner ; all of the best quality, and administered with the greatest propriety and regularity; whilst the introduction of ardent spirits is prohibited, and sobriety enforced, by the strict discipline of the house. ‘On the other hand, we find | that, previous to their admission, they were either addicted to intemperance, or in the habit, at least, of muddling in public-houses, where, after a libation with porter, they in- dulyed in the free use of acidulated punch (the constant nocturnal practice of our middling tradesmen and shop- keepers, who furnish the greatest proportion of our pa- tients). The keeper of a porter-house of considerable re-_ sort informs me, that, to please the generality of his cus- tomers, he finds it necessary to add the juice of an entire lemon to about two quarts of punch; and that, from this circumstance, he would haye experienced a considerable di- 1 | minution 124 ~ On Gravelly and Culculous Concretions. minution of his profits, if he did not occasionally substitute cream of tartar, or the dilute sulphuric acid: an innocent and ‘safe practice, in his opinion. Now, so satisfied are our pa- tients of the pernicious effects of acids of all kinds, that we find many of them refuse to make use of our table beer during the summer months, through the apprehension of its acescent quality (as was before observed), and which con- tinued to be the practice of Hewson, Khensk, Clapham, and others, for years back: nor do our present two greatest suf- ferers, Sing and Cox, venture on it at any season but with the greatest caution, To a removal, then, from the former occasional causes we may attribute no smal] share of the alleviation of those diseases which takes place with us: a practical observation, that cannot be too generally known. But to return to my subject :—On the slightest appearance of gravelly symptoms, unconnected wiih fever, or inflammatory tendency of the urinary system, our patients have recourse to aw alkaline medicine, the gravelly pills (as they term them), which eonsist of desiccated soda, in the most convenient form for hospital practice, as well as most suited to gouty stomachs. Of this (as first advised by Beddoes,) one drachm, with the addition of a few grains of capsicum, or drops of essential, oil, and the necessary quantity of hard soap, or extract, is made into twenty pills. Of these, from three to six, or more, are taken in the twenty-four hours; and are found sufficient, not only to alleviate or remove these complaints, but even to render the interference of the physician but sel- dom necessary. We have had also occasion to remark, that several of our patients, induced by their marked beneficial effects, carried these pills about them, so as to have occa- sional recourse to them, without much attention to either dose or number. To this practice, then, we would be disposed to attribute the very pleasing and interesting consideration, that, among so many gravelly patients, there has not occurred, in the course of ten years, a single operation of lithotomy; nor has the catheter, even in the hands of our expert and able surgeon, Mr. Macklin, been able to discover the smallest - oecasion On Gravelly and Calculous Concretions. 4193 occasion for it. We could therefore have no opportunity of ascertaining the efficacy of injections into the bladder, as recommended by Whyte, Fourcroy, and myself. I shall conclude by observing, that it would be interest- ing to have it in our power to extend these researches to the urine of those who live habitually on different alimient and drinks, particularly of the acescent kind, as well as to that of those who drink watets with mineral alkaline impregna- tions. But this desirable object can be only obtained by the concurrent exertions and attention of gentlemen of the fa- eulty in‘different countries and situations. In private prac- tice it is not to be expected; for here, wherever experiment is surmised to be the object, mistrust and suspicion take place of professional confidence. The use of the nitric acid in our venereal hospital, I hoped, would afford some useful facts as to its effects upon the saline contents of urine; the uric acid in particular. But I had not, as yet, sufficient leisure for that inquiry; nor could I, hitherto, obtain the urine of those using it, with all the circumstances necessary to enable me, at this moment, to draw any direct conclu- sions from my examination of it. In many instances, 4 morbid state of the urinary system (the urethra in particular) took place. In others, the combined effects of mercury in- terfered: and in all, no certainty of its not being blended with the urine of others not using this acid. I could not, however, help observing, that the few specimens, sent to me, agreed in one particular, viz. their exceeding very little, if at all, the usual healthy standard of acidity. This circumstance must excite our attention the more forcibly, when we con- sider, that two drachms of nitric acid, nay, sometimes three, diluted in the proportion of one pint of water to each drachm of acid, were taken daily ; whilst, on the other hand, a few drops of the acid elixir of vitriol, or tincture martis in sp. salis, nay, the weak vegetable acids, and cream of tartar, _ persevered in for a few days, impart an additional degree of acidity to the urine. Would not this observation (if founded), conjoined with the easy decomposable nature of the acid it- self, and its action on animal matter, induce us to lean to the opinion of those who haye already asserted that this acid ned is 196 Memoir upon Guano. is partly decomposed in the system, imparts its oxygett to ity and that, perhaps, to a degree capable of annulling or de- stroying its properties as an acid? And it may be here further remarked, in confirmation of such notion, that those gentlemen most conversant with it here, as well as most capable of judging, entertain strong doubts of its supposed diuretic effects, allowance being made for the necessary quantity of its watery vehicle, If it be, — then, truly deoxygenated in the system, why be deterred by its failure, as a radical cure of siphylis, from extending our trials with it here, to other chronic diseases, as they have already done in India? XXI. Extract of a Memoir of Messrs. Fourcroy and VAUQUELIN upon Guano, the natural Manure of the South Sea Islands near the Coast of Peru. Read before the National Institute. Drawn up by A. LaucieR*. A mone the vast number of objects worthy of the attention .of naturalists which M. Humboldt has observed and col- lected during his late travels, gwano is one of the greatest im- portance. In making us acquainted with this singular sub- stance, one of the principal resources of agriculture in the countries he has visited, this celebrated naturalist has fur- nished the authors of this memoir with an opportunity of confirming a discovery which they had made at the very moment of M. Humboldt’s return. The perusal of their memoir upon the existence of uric acid in the excrement of birds, created the idea in Humboldt that the guano, found in the islands on the coast of Peru frequented by a great num- ber of birds, might be of the same description. It belongs to chemistry alone to decide the degree of credit to which this conjecture is entitled. Messrs, Fourcroy and Vauquelin have undertaken the examination of this substance, and we - purpose laying before our readers the results of their labours as inserted in the Memoirs of the National Institute. * From Annales de Chimie, vol, lvi. p. 258. : Before Memoir upon Guano. . eer Before giving an account of the experiments made upon guano in order to discover its nature, it may not be improper to communicate M. Humboldt’s own opinion, as conveyed jn a note to the authors of this memoir. . « Guano is found in great abundance in the South Sea, on the islands of Chincha, near Pisco; but it exists also on more southern shores and islands, such as Ilo, Iza, and Arica. The inhabitants of Chancay, who make a trathe of guano, go and return from the islands of Chincha in twenty days. Each vessel has on board from 1500 to 2000 cubic feet. A vanega costs at Chancay 14 livres, at Arica 15 livres tournois. << It lies in beds of 50 or 60 feet deep, which are wrought ‘like mines of iron ochre. These islauds are inhabited by an immense quantity of birds, particularly of the ardea {ihe heron) and the phcenicupterus (Aamingo) kinds, which al- ways pass the night on shore; but it requires a period of three centuries before their excrements increase to four or five lines in thickness. Is guano a production caused by changes which the globe has undergone, like coal or fossil wood? The fertility of the otherwise steril shores of Peru is produced by the use of this substance, which ts a staple article of commerce. Fifty small vessels called guaxeros are continually employed in searching for it, and transporting it ‘to the main land; and we may perceive the smell of it ata quarter of a league’s distance. The sailors, who are accus- tomed to this ammoniacal odour, suffer no inconvenience from it, but it caused us to sneeze violently on approaching Gt. For the cultivation of mace, in particular, it furnishes a most excellent inanure. The Indians have taught this me- thod to the Spaniards. If too much guano, however, is thrown upon the mace, the root is burnt up, and destroyed. Guano is extremely acidifiable; so that bere we have a ma- nure of hydrurct of azote, while other manures are rather hydrurets of carbon.” Guano has a reddish yellow colour; it is almost tasteless, but has a strong smell, which resembles at once that of castor and valerian. It blackens in the fire, exhaling a white smoke and an ammoniacal odour. Its 228 Memoir upon Guane. Its solubility in water, and, above all, in potash, deter- mined the method to be taken in its analysis. They suc cessively tried it by means of water, potash, and muriati¢ acid: each of these trials gave occasion to observe several phenomena, of which we shall give a succinct account witbout entering into the details, which may be too exten~ sive for an extract. Ten grammes of this substance, repeatedly washed in great quantities of boiling water, were reduced to 5°7 grammes. The ley had a reddish colour, and reddened turnsole paper. Submitted to distillation in B. M., it furnished ammonia during the whole operation: 24 hours afterwards it depo- sited a reddish yellow powder, a little sapid, having the odour of castor; and it presented on its surface a crystalline pellicle of the same colour as the’ precipitate. The liquor, filtered and evaporated a second time until it was'reduced to 3 grammes, still deposited, on cooling, a red- dish yellow powder, Jike the first, but less abundant. The yellow powder and the mother water which held it in solution were examined separately. The former presented the following properties :—It is a concrete and pulverulent substance, of a brilliant and crystal- line appearance, and of a reddish yellow colour. Exposed to heat, it burns entirely, and gives out a slight empyreumatic odour of ammonia and prussic acid. Although little soluble in cold water, it is easily so in warm, to which it communi- cates a yellowish colour ; and, although the solution is taste- less, it reddens the tincture of turnsole; it precipitates the solutions of acetate of lead and of nitrates of silver and mer- cury in coloured flakes, which the nitric acid redissolves completely. This substance dissolves instantly in an alkaline ley, to which it communicates, a brown colour, exhaling a lively odour of ammonia. ‘Sulphoric acid, mixed with 2 concen- trated alkaline solution, yields a very thick whitish precipi- tate, and liberates a sharp smell similar to that of weak acetic acid. The celebrated authors of the memoir donchidell from these experiments that this powder presents itself as an aci- dulated Memoir upon Guano. - 19g dulated salt, formed from an animal acid, ammonia, and a little lime. In short, very weak nitric acid, in which this salt had been macerated to detach its acid from its bases, yielded, upon evaporation, vapours of ammonia in abun- dance by the addition of potash, and unequivocal signs of lime by the addition of oxalic acid. Freed from ammonia and lime, this substance ig less co- loured, and appears less soluble than before: its solution in boiling water deposits brilliant crystals tclerably hard, and reddens more strongly turnsole paper. It combines with potash easily, and without the smell of ammonia: all the acids separate it from potash. It blackens by heat, and ‘burns without leaving any residue, giving out a smell of ammonia and prussic acid. Its neutral combination with ammonia does not precipitate the solution of sulphate of alumine, as the honistic acid does. It results from .all these facts, 1st, That the substance extricated from guano by boiling water is an acid partly saturated with ammonia and a little lime: gd, That this acid is of an animal nature, since it yields ammonia and prussic acid on being decomposed by fire: 3d, That this acid, according to all the properties already indicated, is uric acid, and similar to that of the excrements of aquatic birds: 4th, That it forms about the fourth part of guano. The mother water which deposited the powder, the pro- perties of which are about to be detailed, is very acid: pot- ash liberates from it ammoniain abundance; it therefore con- tains an ammoniacal salt: the nitrates of barytes and silver announce the presence of the muriatic and sulphuric salts im it also: lime water precipitates from it white flakes, difficult of solution in the muriatic acid. : This precipitate, occasioned by Jime water, is evidently formed Of two salts: both dissolve in the acids without ef- fervescence: the one is easily dissolved; without the assist- ance of heat; the other is dissolved with difficulty, éven by the assistance of heat. The fotmer résists calcination ; the latter is decomposed by fire, and afterwards dissolves in the acids with effervescence. The one rs phosphate and the othet oxalate of lime. Vol. 24. No. 94. March 1606. I The ; 130 Memoir upon Guano. The weak nitric acid was made use of by Fourcroy and Vauquelin with an intention of separating these two salts without making them experience any alteration. It dis- solved the phosphate of lime, without touching the oxalate. This last salt, tried with a solution of carbonate of potash, yielded a precipitate which dissolved with effervescencq’ in the nitric acid: this solution evinced all the properties of nitrate of lime. The acid separated from the lime united with the potash. In short, the liquor presents the charac- ters of the oxalate of potash. Lime water precipitated f from it avery subtle powder. Sulphate of lime precipitated very light flakes, and precipitates were formed by all the metallic solutions which precipitate oxalic acid. Sulphate of alu- mine did not form any precipitate, as might have happened with honistate of potash. The potash which the illustrious authors of the memoir found in the mother water of guano after its precipitation by means.of lime water, the liberation of ammonia which they obtained by the addition of potash in the mother wa- ter before its decomposition by lime water, sufficiently prove that these two alkalies saturate the acids contained in the mother water of guano: thus this mother water certainly contains oxalates, phosphates, sulphates, and muriates of potash and ammonia. © The five grammes and seven-tenths remaining after the action of the water upon the ten grammes of guano sub- mitted to the analysis, were tried by caustic pata which took eigh st-tenths from them: this alkaline solution con~ tained patkivs else than the uric acid, and a small quantity of fatty matter. The muriatic acid, to the action of which the ash gram - mes and nine-tenths not attacked by potash’ had been sub- mitted, did not present upon analysis any thing else than phosphate of lime, iron, and.an atom of carbonate of lime. _ The water, the potash, and the muriatic acid, successively employed, leit no other residue out of ten grammes of guano than three grammes, and a tenth part of a matter which was recognised to be a mixture of a quartzy and ferruginous saad. Fhe Analysis of Birdlime. — 131 The result of this interesting analysis is; that the South a manure is formed, - Of uric acid, which forms the fourth part, and w Heh is S aly saturated with ammonia and lime. . 2. Of oxalic acid, partly saturated with ammonia and pot- ash. 3. Of phosphoric acid, combined with the same bases and with lime. 4. Of small quantities of sulphates and muriates of pot- ash and ammonia. 5. Of a little fatty matter. 6. Of sand, partly quartz and partly iron. The existence of guano in the places where such multi- tudes of birds assemble, the identity of its nature with that of the excrements of aquatic birds, necessarily throw great light upon the origin of this substance. Its analysis proves how well founded the ingenious natu- ralist is in his opinion, to whom we are indebted for out knowledge of this substance, equally interesting to us as useful to the inhabitants of Peru. The analysis, also, con- » firms the important discovery, which is the happy fruit of the researches of Fourcroy and Vauguelin. In short, it has the advantage of recalling this well known truth, that the sciences mutually enrich each other, in aiding each othet with the various lights they possess; and it furnishes a new occasion to remark, that among all the sciences none have a more immediate and-more necessary connection than che- mistry and natural history. XXU. Analysis of Birdlime. By M. Bovuitton- LaGRANGE*, I. Origin and Mode of Preparation. The substance termed birdlime is classed among the im- mediate products of vegetables. M, Fourcroy is the first who regarded it as glutinous: he has placed it as a species ® From the Annales de Chimic, tom. bv. jr} undger- 132 ; Analysis of Birdlime. under this general head in his Systéme de Connoissances Chimiques, vol. vii. p. 306. Birdlime, says this chemist, is proenrel from the fruit of the misletoe and the tender bark of the holly, as well as from many other trees, by maceration in water. Although no one has hitherto examined this substance with sufficient accuracy, it presents many points of resemblance to gluti- nous bodies.: With the exception of what is said in my Manual of a Course of Chemistry, I know no work in which any light is thrown upon the nature of this singular matter. M. Chaptal, in his Elements of Chemistry, speaks only of its preparation: as the process-«which is there detailed differs in nothing from that which is found in the Materia Medica of Geoffroy, and in the Dictionary of Valmont de Bomare, I shall quote the article respecting the preparation of this substance :—* The antients employed the berries of the misletoe of the oak: they boiled the fruit in water, then. bruised them, and strained off the warm liquor, so as to se- parate the seeds and skins. But we now prefer the bird- dime procured from the bark of the holly: the inner bark, which is the tenderest and greenest, is made choice of, and allowed to putrefy under ground; it is then beaten in mortars to reduce it into a paste, which is washed and kneaded in water... This substance was considered as resolvent and emollient when applied externally.” We know also that the misletoe of the oak forms an in- gredient in many pharmaceutical preparations, such as the universal water, the antispasmodic powder, and Guttet’s powder. The English, according to Geoffroy, prepate their birdlime from the bark of the holly. They boil this bark, says he, in water for seven or cight hours, until it has become tender. It is then formed into balls, which are placed under ground, in numerous layers, one above another, with pebbles inter- posed; the water being previously all drained off: there they are suffered to remain to ferment and putrefy for a fort- night or three weeks, until: they have been convefted into mucilage. They are next removed and pounded in a mortar till Analysis of Birdlime. 133 till they can be worked like paste; after this they are washed in a stream of water, and kneaded together, so as to remove all foreign matters. The paste is now deposited in earthen vessels for four or five days, till it throws up a scum and purifies. It is then put up in proper vessels, and is ready for sale. This. mode of preparing it is not generally adopted ; each county has its own process, and there are even some persons who keep their method secret. At Nogent-le-Rotron birdlime is prepared from the shreds of the second bark of the holly: it is allowed to ferment in a moist place for fifteen days, and then boiled in water, which is afterwards evaporated. At Commercy and in its vicinity this substance is pro- cured from different shrubs, as the holly, the viburnwm lan-— tana, and the niisletoe; from every different tree, such as the apple, the pear, the lime, &c. The best is obtained from the prickly holly, and is of a ' greenish colour: that which is made from the viburnum Jantana is yellowish. When this vegetable is employed, they uniformly reject the epidermis, and use only the second bark. I prepared the birdlime which I used in my experiments from the inner bark of the holly. On comparing it with some which was made with great care, and sent me from Commercy, I was unable to discover any sensible difference. These precautions appeared to me necessary, that.a greater degree of accuracy might be given to the analysis. We well know that the birdlime of commerce is seldom pure ; it is often a mere mixture of vegetable and animal matter, and often adulterated with turpentine, oil, vinegar, &c.:/it is therefore absolutely necessary to ascertain previously the purity of this substance ; and the process which I adopted yielded me birdlime of the best quality. I took the inner bark of the holly, bruised it‘well, them boiled it in water about four or five hours, and, having thrown out the water, placed the bark in earthen pots under ground: I allowed it to remain there till it putrefied, or rather became viscid, taking care to sprinkle it with water bY: he from 134 Analysis of Birdlime. from time to time. When this process was completed I washed it, so as to remove all foreign matters. JI. Chemical and Physical Properties of Birdlime. Birdlime has a greenish colour; its taste is bitter: it is glutinous, ropy, and tenacious: its odour resembles that of linseed oil, When spread upon a plate of glass, and exposed for some time to the air and light, it dries and becomes brown. In this state it is no longer viscid: when it is completely dried it may be reduced to. powder; it has then Jost all its gluti- nous properties, and it cannot resume them by the addition of water, Birdlime reddens the tincture of turnsole. When heated alone in a porcelain cup it melts without becoming very li- quid; it swells up and forms bubbles, which rise to the sur- face and then burst. This kind of fusion discovers small black grains, which give it an uneven appearance: it diffuses an odour very similar to that of the fat oils when their tem- perature is raised. If the birdlime be kept in fasion for some time, it ac- quires a browifish colour; but again resumes all its proper- ties on cooling. When placed upon red embers it burns with a flame, and emits an abundance of smoke. Heated in a crucible of platina, it burns as soon as the crucible becomes red. Its flame is bright, and rises above seven inches: it is attended with a considerable quantity of smoke, which is readily condensed upon the vault of the chimney. ‘The combustion continues even after the crucible is removed from the fire. There remains a white cinder, which is very alkaline, and partly soluble in water. By the use of re-agents we ascertain the presence of sulphate and muriate of potash. The portion which is insoluble in water, when treated with the muriatic acid, dissolves with effervescence. The solution is copiously precipitated by the oxalate of ammonia; prussiate of potash produces a blue precipitate ; and with ammonia it lets fall a matter of a pasty consist- ence, which is partly soluble in caustic potash: from these facts Analysis of Birdlime. 135 facts we should be led to conclude, that the ashes contain, besides the salts soluble in water, a quantity of the carbo- nates of lime and alumine, with a little iron. Water has very little action upon birdlime. When raised to boiling, the matter does not completely melt; it acquires rather more fluidity, but resumes its former consistence by cooling. The water has no colour; its taste is nauseous, and then bitter: it reddens the tincture of turnsole. When evaporated to the consistence of syrup it becomes coloured, and assumes a mucilaginous appearance. The admixture of alcohol separates this matter. Water, therefore, only dissolves a mucilaginous substance, and a little extractive matter. . Caustic potash, on the other hand, has a very different action. Its concentrated solution immediately forms with birdlime a whitish mayma, which becomes brown by eva- poration: there is at the same time a disengagement of am- monia. The compound formed is Jess viscid: it acquires a greater hardness by exposure to the air: its odour and taste are si- milar to those of soap. It is completely soluble in alcohol, with the exception of a few vegetable remains. These solutions become muddy on the addition of the strong acids, and exhibit the othes phenomena which are observed in the solutions of soap. The weaker acids soften birdlime, and partly dissolve it : but when concentrated they act in a different manner. Sul- phuric acid blackens and chars it: if powdered lime be added so as to form a thick magma, a disengagement of acetic acid and ammonia takes place: there is no doubt that, besides the free acetic acid contained in the birdlime, a new quantity is formed by the action of the sulphuric acid. The nitric acid has little action in the cold upon the sub- ‘stance under examination ; but if the temperature be raised it becomes yellow, melts, and as the evaporation proceeds the matter swells considerably, and a bard brittle mass re- mains. When submitted a second time to the action of the nitric acid, a solution is effected, and a part of this substance 14 is 136 Analysis of Birdlime. is converted into the malic and oxalic acids. By continuing the evaporation we obtain a yellow and very friable matter, which softens hetween the fingers like wax, possessing at the same time a degree of elasticity, and melts with a gentle heat. Potask combines with this matter, changes its yellow co- lour to a brown, and forms with it a true soap. i Alcohol dissolves it in part; forming a yellow solution, which loses.its transparency on the addition of water. If the alcohol be evaporated to dryness, a yellow substance remains, which has no longer a greasy appearance, and dit- fuses an agreeable odour when burnt. Muriatic acid has no action on birdlime in the cold, but, when heated, blackens it, Oxymuriatic acid, on the other hand, has a very different and more powerful action on this substance. On passing thé gas through water containing liquefied birdlime, or by shaking it it in a flask along with very strong acid, we observe the following se adhere :—-the hirdlime speedily loses its colour, becoming white; itis now no longer yiscid, and separates into hard compact masses, which contain within them a portion of the substance unaltered. This incom- plete oxygenation may be ascribed, with great probability, to the difficulty of preserving the birdlime liquid in hot way ter, and the consequent obstacle to the action of the acid beyond the external layer. The characters of oxygenated birdlime are: Ist, It may be readily reduced to powder: 2d, It is insoluble in. water even when heated: 3d, It refuses to melt at an elevated tem- perature: 4th, It does not become yellow, or form resin, when subjected to the action of the nitric acid, The acetous acid softens birdlime, and dissolves a certain portion of it: the solution has a yellow colour and a nau; seous taste: with the carbonate af potash it lets fall no pre-~ cipitate : when evaporated it yields a matter which has the properiies of a resin, but cannot be reduced to a state of complete dryness. Some of the metallic oxides are readily reduced when heated with birdlime, The Analysis of Birdlime,* 137 The semi-vitreous oxide of lead acquires a gray colour, dissolves, and forms a kind of plaster with this substance. Boiling alcohol, of forty degrees strength, dissolves bird- lime: the solution is clear, transparent, and of a yellow co- lour, but as it cools it becomes muddy. By the filter we can separate from the solution a yellow matter which softens more readily than entire birdlime, and which melts with a gentle heat; diffusing an odour very si- milar to that of wax, which indeed it resembles in all its characters, The filtered liquor is bitter, nauseous, and acid; it lets fall a precipitate by water, and leaves on evaporation a sub- stance similar to resin. ; Sulphuric ether may be regarded as the true solvent of birdlime: it acts ppon this substance readily, divides, and in the‘end dissolves it almost entirely, leaving a little vege- table matter. The liquor assumes a greenish yellow colour, and reddens strongly the tincture of turnsole. By the addi- tion of a small quantity of water it becomes muddy, and the | ether rises to the surface; but if the water be added in suf- ficient quantity to dissolve the ether, a layer of oil exactly similar to the oil of linseed forms on the surface: with the semi-vitreous oxide of lead this last forms a plaster. The ethereal solution yields, by evaporation, a yellow substance, which is greasy and soft like wax. Conclusion. From what has been now stated it must be very apparent that little analogy exists between birdlime and glutinous matter. A simple recapitulation will suffice to point out the proper place which this substance ought to occupy among the pro- ducts of vegetables. Birdlime is viscid and elastic; it dries slightly by expo- sure to the air, and becomes brown, but never acquires the brittleness and unalterable properties of glue. It melts in the fire, inflames, swells up, and burns with a bright flame; but does not diffuse that animal odour which gluten is observed to do, * Water 138 Oma new Varnish for Wood. Water does not dissolve birdlime, but merely takes up the mucilage, extractive matter, and acetic acid, which this sub- stance contains. Alkalies dissolve it, and when inte ola they convert it into a true soap. Weak acids soften, and in part dissolve birdlime. The concentrated sulphuric acid blackens and chars it. Nitric acid communicates to it a yellow colour, and con- verts it partly into the oxalic and malic acids, and partly into resin and wax. The oxymuriatic acid renders it white and dolidh forming oxygenated birdlime. Alcohol has little action on birdlime; it merely dissolves ‘the resin and takes up the acid. Lastly, Sulphuric ether dissolves it entirely. Birdlime, therefore, differs from glue in the following par- ticulars : 3, It contains a quantity of free acetous acid. g. It has very little of an animal nature. ’ 3. Both mucilage and extractive matter may be obtained from it. 4. By the action of the nitrie acid it yields a large quan- tity of resin. 5. It is soluble in ether. XXII. On @ new Varnish for WYood. By M. Par- MENTIER *, Bi apothecary of the French military hospital at Génes, , M. Bompoix, has sent me some coffee-cups, the chief merit of which appeared at first to arise from their lightness, but afterwards I discovered that they were still far superior on account of the varnish which covered them. This varnish enjoys a great reputation, and the composition of it is kept a profound secret in that country; I therefore charged M. Bompoix to use every exertion to discover the recipe from which it is made; and he at last obtained it by means of one of his pupils, whose intimacy with the master of the * From Annales de Chimie, tome lvi. : manufactoty On a new Varnish for Wood. . 139 manufactory procured him the following recipe, and an ar- ticle was produced by the use of i it equ walt in quality to the original : Take of linseed oil one pound and a half. Amber, one pound. Pulverized litharge, five ounces. Pulverized minium (red lead) five ounces. Pulverized white lead, five ounces. Boil the linseed oil in an unglazed vessel’; make a bag of Jinen in which the litharge, minium, and white lead may be contained ; and suspend it, with its contents, in the vessel ; taking care not to allow it to touch the bottom. Continue the ebullition until the oil begins to become brown ; then take out the bag with its ingredients and continue to boil ihe oil, adding a clove of clean garlic; and when this is dried up put in another, and so on to the number of six or seven. Then melt the amber in an unglazed earthen vessel in the following manner, and when melted pour it into the prepared linseed oil. . ‘ Manner of melting the Amler. Take about two ounces of the linseed il and add it to the amber, and facilitate its melting by a strong fire: when it is melted mix it with the rest of the linseed oil and boil the whole two minutes ; then remove it and strain it through a fine linen cloth ; and when it is cold put it into a botile and stop it well, in order to prevent it from drying up. Manner of using it, Take the article which you want to varnish, and polish it well before applying the varnish, which is to be lone in the following manner: Take lamp black, the varnish thus prepared, and a liitle essence of turpentine ; mix them together, and with a pencil lay a coating upon the piece which js to be varnished ; when that coat is dry lay on others to the number of four; and when these are dry also, place the article in a stove or fur- nace, 140 Effects of Heat modified by Compression. nace, in order to dry it entirely, and afterwards polish it with powdered pumice-stone and Tripoli. Manner of preparing the Article which is to le varnished. It is necessary to make use of walnut-tree, ash, or cherry- tree wood, because these woods are porous, and when they are perfectly dry they will turn better in the lathe; when the article is shaped to your liking you must put it into a stove to dry, alter which work it and polish it as if it was to be completely finished, then apply the varnish in the manner above described. If it 1s wanted to give the dish a red colour, a little mi- nium, or rather cinnabar, may be put into the varnish ; and the same may be done with any other colour you wish to give to the article varnished. ARXIV. Account of a Series of Experiments, showing the Effects of Compression in modifying the Action of Heat. By Sir James Haru, Bart. F.R.S. Edin* J. Antient Revolutions.of the Mineral Kingdom.—Vain At- tempts to explgin them.— Dependence of Geology on Che- mistry.—Importance of the Carbonate of Lime.—Dr. Black’s Discovery of Carbonic Acid subverted the former Theories depending on Fire, but gave Birth to that of Dr. Hutton.—-Progress of the Author’s Ideas with regard to that Theory. -— Experiments with Heat and Compression, suggested to Dr. Hutton in 1790.—Undertaken ln y the Author in 1798.—Speculations on which his Hopes of Suc- cess were founded. Waorver has attended to the structure of rocks and mountains, must be convinced that our globe has not always existed in its present state ; but that every part of its mass, so far at least as our observations reach, has been agitated and subverted by the most violent revolutions. * From Transactions of the Royal Society of Edinburgh, vol. vii. Facts Effects of Heat modified ly Compression. 141 Facts leading to such striking conclusions, however imper- fectly observed, could not fail to awaken curiosity, and give rise to a desire of tracing the history, and of investigating the causes, of such stupendous events ; and various attempts were made in this way, but with little success; for, while discoveries of the utmost importance and accuracy were made in astronomy and natural philosophy, the systems produced by the geologists were so fanciful and puerile, as scarcely to deserve a serious refutation. One principal cause of this failure seems to- have lain in the very imperfect state of chemistry, which has only of Jate years begun to deserve the name ofa science. While chemistry’ was in its infancy, it was impossible that geology should make any progress ; since several of the most important circumstances to. be accounted for by this latter science are admitted on all hands to depend upon prin- ciples of the former. The consolidation of loose sand into strata of solid rock ; the crystalline arrangement of sub- stances accompanying those strata, and blended with them in various modes ; are circumstances of a chemical nature, which all those who have attempted to frame theories of the earth haye endeavoured by chemical reasonings to reconcile to their hypotheses. , Fire and water, the only agents in nature by which stony substances are preduced, eaniold our observation, were em- ployed by contending sects of geologists to explain all the phenomena of the aimed kingdom. But the known properties of water are quite repugnant to the belief of its universal influence, since a very great pro- portion of the substances under consideration are insoluble, or nearly so, in that fluid; and since, if they were all ex- tremely soluble, the quantity of water which is known to exist, or that could possibly exist, in our planet, would be far too smal! to accomplish the office assigned to it in the Neptunian theory *. On the other hand, the known pro- perties of fire are no less inadequate to the purpose ; for va- rious substances which frequently occur in the mineral king- * Ilustrations of the Huttonian,Theory, by Mr. Professor Playfair, 459. dom, 142 Effects of Heat modified by Compression. dom, scem, by their presence, to preclude its supposed agency; since experiment shows, that, in our fires, they are totally changed or destroyed. Under such circumstances the advocates of either element were enabled, very successfully, to refute the opinions of their adversaries, though they could but feebly defend their own: and owing perhaps to this mutual power of attack, and for want of any alternative to which the opinions of men could lean, both systems maintained a certain degree of credit ; and writers on geology indulged themselves, with a sort of impunity, in a style of unphilosophical reasoning which would not have been tolerated in other sciences. Of all mineral substances the carbonate of lime is un- questionably the most important in a gencral view. As limestone or marble it constitutes a very considerable part of the solid mass of many countries, and in the form of veins and nodules of spar pervades every species of stone. Its history is thus interwoven in such a manner with that of the mincral kingdom at large, that the fate of any geolovical theory must very much depend upon its successful applica- tion to the various conditions of this substance. But till Dr. Black, by his discovery of carbonic acid, explained the chemical nature of the carbonate, no rational theory could be formed of the chemical revolutions which it has undoubt- edly undergone. This discovery was in the first instance hostile to the sup- posed action of fire; for the decomposition of limestone by fire in every common kiln being thus proved, it seemed ab- surd to ascribe to that same agent the formation of lime* stone, or of any mass containing it. The contemplation of this difficulty led Dr. Hutton to view the. action of fire ina manner peculiar to himself, and thus to form a geological theory, by which, in my opinion, he has furnished the world with the true solution of one of the most interesting problems that has ever engaged the attention of men of science. He supposed, I. ‘That heat has acted; at some remote period, on al rocks, That Effects of Heat modified by Compression. 148 Ii. That during the action of heat all these rocks. (even such as now appear at the surface) lay covered by a superin- cumbent mass, of great weight and strength. II]. That in consequence of the combined action of heat _and pressure, effects were produced difierent from those of heat on common océasions ; in particular, that the carbonate of lime was reduced to a state of fusion, more or less com- plete, without any calcination. The essential and characteristic principle of his theory is thus comprised in the word compression ; and by one bold hypothesis, founded on this principle, he undertook to meet all the objections to the action of fire, and to account for those circumstances in which minerals are found to differ ‘from the usual products of our furnaces. This system, however, involyes so many suppositions, apparently in contradiction to common experience, which meet us on the very threshold, that most men have hitherto been deterred from the investigation ef its principles, and only a few individuals have justly appreciated its merits. It was long before I belonged to the latter class; for I must own that, on reading Dr. Hutton’s first geological publica- tion, I was induced to reject his system entirely, and should probably have continued still to do so, with the great ma- jority of the world, but for my habits of intimacy with the author ; the vivacity.and perspicuity of whose conversation formed a striking contrast-to the obscurity of his writings. 1 was induced by that charm, and by the numerous original facts which his system had Jed him to observe, to listen to his arguments in favour of opimions which I then looked upon as visionary. I thus derived from his conversation the same advantage which the world has lately done from the publication of Mr. Playfair’s Illustrations ; and experienced the same influence which is now exerted by that work on the minds of our most eminent men of science. After three years of almost daily warfare with Dr. Hutton, on the subject of his theory, I began to view his funda~- mental principles with Jess and less repugnance. There is a period, I believe, in all scientific investivations, when the conjectures of genius.cease to appear extravagant, and when 4 we 144 Effects of Heat modified by Compression. we balance the fertility of a principle, in explaining the phenomena of nature, against its improbability as an hypo- thesis : the partial view which we then obtain of truth is perhaps the most attractive of any, and most powerfully stimulates the exertions of an active mind. The mist which obscured some objects dissipates by degrees, and allows’ them to appear in their true colours ; at the same time, a distant prospect opens to our view, of scenes unsuspected before. Entering now seriously into the train of reasoning fol- lowed by Dr. Hutton, I conceived that the chemical affects ascribed by him to compression, ought, in the first place, to be investigated ; for unless some good reason were given us for believing that heat would be modified by pressure, im the manner alleged, it would avail us little to know that they had acted together. He rested his belief of this influence on analogy, and on the satisfactory solution of all the phzno- mena furnished by this suppusition. It occurred to me, however, that this principle was susceptible of being esta- blished in a direct manner by experiment, and I urged him _to make the attempt ; but he always rejected this proposal, on account of the immensity of the natural agents, whose operations he supposed to lie far beyond the reach of our imitation ; and he seemed to imagine that any such attempt must undoubtedly fail,and thus throw discredit on opinions already sufficiently established, as he conceived, on other principles. I was far, however, from being convinced by these arguments; for, without being able to prove that any artificial compression to which we could expose the car- bonate would effectually prevent its calcination in our fires, 1 maintained, that we had as little proof of the contrary, and that the application of a moderate force might possibly perform all that was hypothetically assumed in the Huttonian theory. On the other hand, I considered myself as bound in practice to pay deference to his opinion, in a field which he had already so nobly occupicd, and abstained, during the remainder of his life, from the prosecution of some ex- periments with compression which I had begun in 1790. Tn 1798 J resumed the subject with eagerness, being stilk of Effects of Heat modified by Compression. 145 df opinion that the chemical law which forms the basis of the Huttonian theory ought, in the first place, to be investi- gated experinientally ; all my subsequent reflections and observations having tended to confirm my idea of the im= portance of this pursuit, without in any degree rendering me more apprehensive as to the result. In the arrangement of the following paper I shall first confine myself to the investigation of the chemical effects of heat and compression, reserving to the concluding part the application of my results to geology. I shall then appeal to the volcanos, and shall endeavour to vindicate the laws of action assumed in the Huttonian theory, by showing that lavas, previous to their eruptions, are subject to similar laws ; and that the volcanos, by their subterranean and submarine exertions, must produce, in our times, results similar to those ascribed, in that theory, to the former action of fire. In comparing the Huttonian operations with those of the volcanos, I shall avail myself of some facts, brought to light in the course of the following investigations, by which a precise limit is assigned to the intensity of the heat, and to the force of compression, required to fulfil the condi- tions of Dr. Hutton’s hypothesis : for according to him the power of those agents was very great, but quite indefinite; it was therefore impossible to compare their supposed effects in any precise manner with the phenomena of nature, My attention was almost exclusively confined to the car- bonate of lime, about which I reasoned as follows: the carbonic acid, when uncombined with any other substance, exists naturally in a gaseous form at the common tempera- ture of our atmosphere ; but when in union with lime, its volatility is repressed, in that same temperature, by the che- mical force of the earthy substance which retains it ina solid form. When the! temperature is raised to a full red- heat, the acid acquires a volatility by which that force is overcome, it escapes from the lime, and assumes its gaseous form. It is evident, that were the attractive force of the lime increased, or the volatility of the acid diminished by Vol. 24. No. 94, March 1806. | K any 146 Effects of Heat modified iy Compression. any means, the compound would-be enabled to bear & higher heat without decomposition than it can in the present state of things. Now pressure must produce an effect of this kind ; for when a mechanical force opposes the expan sion of the acid, its volatility must, to a certain degree, be diminished. Under pressure, then, the carbonate may be expected to remain unchanged ina heat by which, in the open air, it would have been calcined, But experiment alone can teach us what compressing force is requisite to enable it to resist any given elevation of temperature, and what is to be the result of such an operation. Some of the ‘compounds of lime with acids are fusible, others refrac- tory; the carbonate, when constrained by pressure to en- dure a proper heat, may be as fusible as the muriate, One circumstance, derived from the Huttonian theory, induced me to hope that the carbonate was easily fusible, and indicated a precise point under which that fusion ought to be expected. Nothing is more common than to meet with nodules of calcareous spar inclosed in whinstone ; and we suppose, according to the Hutionian theory, that the whin and the spar had been liquid together, the two fluids keeping separate like oil and water. It is natural, at the junction of these two, to look for indications of their relative fusibilities ; and we find, accordingly, that the termination of the spar is generally globular and smooth; which seems to prove that, when the whin became solid, the spar was still in-a liquid state ; for had the spar congealed first, the tendency which it shows, on all occasions of freedom, to shoot out into prominent crystals, would have made it dart into the liquid whin, according to the peculiar forms of its crystallization, as has happened with the various substances contained in whin, much more refractory than itself, namely, augite, felspar, &c., all of which having congealed im the Jiquid whin, have assumed their peculiar forms with perfect regularity. From this F concluded, that when the whin congealed, which must have happened about 28° or 30° of Wedgwood, the spar was still liquid. I therefore expected, if I could compel the carbonate to bear a heat of 28° . ‘ Effects of Heat modified by Compression. 147 28° without decomposition, that it would enter into fusion. The sequel will show that this conjecture was not without foundation. I shal] now enter upon the description of those experi- ments, the result of which £ had the honour to lay before this society on the 30th of August last (1804) ; fully aware how difficult it is, in giving an account of above five hun dred experiments, all tending to one point, but differing much from each other in various particulars, to steer be- tween the opposite faults of prolixity and barrenness. My object shall be to describe, as shortly as possible, all the methods followed, so as to enable any chemist to repeat the experiments; and to dwell particularly, on such cir- cumstances only as seem to lead to conclusions of im- portance. The result being already known, I consider the account I am about to give of the execution of these experiments, as addressed to those who take a particular imterest in the pro- gress of chemical operations :—in the eyes of such gentlemen I trust that none of the details into which I must enter will appear superfluous. Il. Principle of Execution upon which the following Expe- riments were conducted.— Experiments with Gun- Barrels filled with baked Clay, and welded at the Muxxle—Me- thod with the Fusible Metal.—Remarkalle Effects of its Expansion.— Necessity of introducing Air.—Results ob- tained. When I first undertook to make experiments with heat acting under compression, I employed myself in contriving various deyices of screws, of bolts, and of lids, so adjusted, LT hoped, as to confine all elastic substances ; and perhaps some of them might have answered. But I laid aside all such devices, in favour of one which occurred to me in January 1798 ; which, by its simplicity, was of easy appli- cation in all cases, and accomplished all that could be done by any device, since it secured perfect strength and tight- ness to the utmost that the vessels employed could bear, Whether formed of metallic or earthy substance. The device K 2 depends 148 Effects of Heat modified by Compression. depends upon the following general view: If we take a hol low tube or barrel (AD, fig. 1. Plate IV.) closed at one end and open at the other, of one foot or more in length, it is evident, that by introducing one end into a furnace, we can apply to it as great heat as art can produce, while the other end is kept cool, or, if necessary, exposed to extreme cold. Tf then the substance which we mean to subject to the com- bined action of heat and pressure be introduced into the breech or closed end of the barrel (CD), and if the middle part be filled with some refractory substance, leaving a small empty space at the muzzle (AB), we can apply heat to the muzzle, while the breech containing the subject of experi- ment is kept cool, and thus close the barrel by any of the numerous modes which heat affords, from the welding of iron to the melting of sealing-wax. Things being then re- versed, and the breech put into the furnace, a heat of any required intensity may be applied to the subject of experi- ment, now in a state of constraint. My first application of this scheme was carried on with a common gun-barrel, ‘cut off at the touch-hole, and welded very strongly at the breech by means of a plug of iron. Into it I introduced the carbonate, previously rammed into a cartridge of paper or pasteboard, in order to protect it from the iron, by which, in some former trials, the subject of experiment had been contaminated throughout during the action of heat. I then rammed the rest of the barrel full of pounded clay, previously baked in a strong heat, and I had the muzzle closed, like the breech, by a plug of iron welded upon it in a common forge; the rest of the barrel being kept cold during this operation by means of wet cloths. The breech of the barrel was then introduced horizontally into a common muffle, heated to about 25° of Wedgwood. To the muzzle a rope was fixed in such a manner that the barrel could be withdrawn without danger from an explo- sion*. I likewise, about this time, closed the muzzle of é : the * On one occasion the importance of this’ precaution was strongly felt. Haying inadvertently introduced a considerable quantity of moisture intoya welded barrel, an explosion took plece, before the heat had risen to redness, wiiadow ~ 6s by Effects of Heat modified by Compression. 149 the barrel by means of a plug fixed by solder only ; which method had this peculiar advantage, that I could shut and open the barrel without having recourse to a workman. In these trials, though many barrels yiclded to the expansive force, others resisted it, and afforded some results that were in the highest degree encouraging, and even Satisfactory, could they have-been obtained with certainty on repetition of the process. In many of them chalk, or common lime- stone previously pulverised, was agglutinated into a steny mass, which required a smart blow of a hammer to break it, and felt under the knife like a common limestone; at the same time the substance, when thrown into nitric acid, dis- solved entirely with violent effervescence. In one of these experiments, owing to the action of heat on the cartridge of paper, the baked clay, which had been used to fill the barrel, was stained black -throughout, to the distance of two-thirds of the length of the barrel from its breech. This circumstance is of importance, by showing, that though all is tight at the muzzle, a protrusion may take place along the barrel, greatiy to the detriment of complete compression: and, at the same time, it illustrates what has happened occasionally in nature, where the bituminous matter seems to have been driven by superior Jocal heat from one part of a coaly bed, though retained in others, under the same compression ; the bitumen so driven off being found, in other cases, to pervade and tinge beds of slate and of sandstone. I was employed in this pursuit in spring 1800, when an event of importance interrupted my experiments for about a year. But I resumed them in March 1801, with many new by which part of the barrel was spread out to a flat plate, and the furnace was blown to pieces. Dr. Kennedy, who happened to be present on this occasion, observed, that notwithstanding this accident, the time might come when we should employ water in these experiments to assist the force of compression. I have since made great use of this valuable suggestion: but he scarcely lived, alas! to see its application ; for my first success in this way took place during his last illness.—] have been exposed to no risk in any other experiment with iron barrels; matters being so arranged that the strain against them has only commenced in a red heat, in which the metal has been so far softened as to yield by laceration like a piece of leather. K 3 . plans 150 Effects of Heat modified ly Compression. plans of execution, and with considerable addition. to my apparatus. In the course of my first trials, the following mode of execution had occurred to me, which I now began to put in practice, It is well known to chemists that a certain com-~ position of different metals* produces a substance so fusible as to melt in the heat of boiling-water. I conceived that great advantage, both in point of accuracy and dispatch, might be gained in these experiments, by substituting this metal for the baked clay above mentioned: that after intro- ducing the carbonate into the breech of the barrel, the fusi- ble metal, in a liquid state, might be poured in so as to fill the barrel to its brim: that when the metal had cooled and become solid, the breech might, as before, be introduced into a muffle, and exposed to any required heat, while the muzzle was carefully kept cold. In this manner, no part of the fusible metal beimg melted but what lay at the breech, the rest, continuing ina solid state, would effectually con- fine the carbonic acid; that after the action of strong heat had ceased, and after al] had been allowed to cool com- pletely, the fusible metal might be removed entirely from the barrel, by means of a heat little above that of boiling- water, and far too low to occasion any decomposition of the earbonate by calcination, though acting upon it in freedom ;_ and then that the subject of experiment might as before be taken out of the barrel. This scheme, with yarious modifications and additions which practice has suggested, forms the basis of most of the . following methods. In the first trial a striking phenomenon occurred, which gave rise to the most important of these modifications. Having filled a gun-barrel with the fusible metal without any carbonate, and having placed the breech in a mufle, I was surprised to see, as the heat approached to redness, the liquid metal exuding through the iron in innumerable mi- nute drops dispersed all round the barrel. As the heat ad- vanced this exudation increased, till at last the metal flowed out in continued streams, and the barrel was quite destroyed. * Fight parts of bismuth, five of lead. ‘and three of tin, On Effects of Heat modified by Compression. 152. On several occasions of the same kind, the fusible metal, being forced through some very minute aperture in the barrel, spouted from it to the distance of several yards, de- positing upon any substance opposed to the stream a beau- tiful assemblage of fine wire exactly in the form of wool. I immediately understood that the phenomenon was pro- duced by the superior expansion of the liquid over the solid metal, in consequence of which the fusible metal was driven through the iron as water was driven through silver* by me- chanical percussion in the Florentine experiment. It oc- curred to me that this might be prevented by confining along with the fusible metal a small quantity of air, which, by yielding a little to the expansion of the liquid, would save the barrel, This remedy was found to answer completely, and was applied in all the experiments made at this timef. I now proposed, in order to keep the carbonate clean, to inclose it in a small vessel; and to obviate the difficulty of removing the result at the conclusion of the experiment, I further proposed to connect that vessel with an iron ramrod, * Essays of Natural Experiments made in the Academie del Cimento, translated by Waller, London, 1634, page 117. The same in Musschen- broek’s Latin translation, Lugd. Bat. 1751. p.63. + I found it a matter of much difficulty to ascertain the proper quantity of air which ought to be thus inclosed. When the quantity was too great, the result was injured by diminution of elasticity, as I shall have occasion fully to show hereafter. When too small, or when by any accident the whole of this included air was allowed to escape, the barrel was destroyed. I hoped to ascertain the bulk of air necessary to give liberty to the expan- sion of the liquid metal, by measuring the actual Bats expelled by known heats from an open barrel filled with it. But I was surprised to find that the quantity thus discharged exceeded in bulk that of the air which, in the same heats, I had confined along with the carbonate and fusible metal in many successful experiments. As the expansion of the liquid does not seem capable of sensible diminution by an opposing force, this fact can only be accounted for by a distention of the barrel. In these experiments then the expansive force of the carbonic acid, of the included air, and of the fusible metal, ‘acted in combination against the barrel, and were yielded to in part by the distension of the barrel, and by the condensation of the included air. My object was to increase the force of this mutual action, by diminishing the quantity of air, and by other devices to be mentioned hereafter. Where so many forces were concerned, the laws of whise variations were unknown, much precision could not be expected, nor isit wonderful that, in attempting to carry the compressing force to the utmost, I should have destroyed barrels innumerable. K 4 longer 152 Effects of Heat modified by Compression. longer than the barrel, by which it could be introduced or withdrawn at pleasure. A small tube of glass*, or of Reaumur’s porcelain, about a quarter of an inch in diameter, and one or two inches in length (fig. 2. A), was half filled with pounded carbonate of lime, rammed as hard as possible ; the other half of the tube being filled with pounded silex, or with whatever oc- curred as most Jikely to prevent the intrusion of the fusible metal in its liquid and penetrating state. This tube so filled was placed in a frame or cradle of iron (dfkh, figs. 3, 4, 5, and 6,) fixed to the end (m) of a ramrod (mn). The cradle was from six to three inches in Jength, and as much in dia- meter @s a gun-barre] would admit with ease. Tt was com- posed of two circular plates df iron (defg and hikl, seen _ edgewise in the figures), placed at right angles to the ram- rod, one of these plates (def) being fixed to it by the centre (m). These plates were connected together by four ribs or flattened wires of iron (dh, e7, fk, and gl), which formed the cradle into which the tube (A), containing the carbonate, was introduced by thrusting the adjacent ribs asunder. Along with the tube just mentioned, was intro- duced another tube (B) of iron or porcelain, filled only with air. Likewise, in the cradle, a pyrometerf piece (C) was * [have since constantly used tubes of common porcelain, finding glass much too fusible for this purpose, + The pyrometer-pieces used in these experiments were made under my own eye. Necessity compelled me to undertake this laborious and difficult. work, in whichI have already so far succeeded as to obtain a set of pieces which, though far from complete, answer my purpose tolerably well. 1 had lately an opportunity of comparing my set with that of Mr. Wedgwood, at various temperatures, in furnaces of great size and steadiness. The result has proved that my pieces agree as well with each other as his, though with my set each temperature is indicated by a different degree of the scale, J have thus been enabled to construct atable, by which my observations have been corrected, so that the temperatures mentioned in this paper are such as would have been indicated by Mr. Wedgwocd’s pieces. — By Mr. Wedgwood’s pieces, I mean those of the only set which has been sold tp the public, and by which the melting heat of pure silver is indicated at the 22d degree. I am well aware that the late Mr. Wedgwood, in his Table of Fusibilities, has stated that fusion as taking place at the 28th degree; but I am convinced that his ob- servations must have been made with some set different from that which was afterwards sold. placed Effects of Heat modified by Compression. 153 placed in contact with (A) the tube containing the car- bonate. These articles generally occupied the whole cradle ; when any space remained it was filled up by a piece of chalk dressed for the purpose. (Fig. 4. represents the cradle filled, as just described.) Things being thus prepared, the gun-barrel, placed erect with its muzzle upwards, was half filled with the liquid fusible metal. The cradle was then introduced into the barrel, and plunged to the bottom of the liquid, so that the carbonate was placed very near the breech (as represented in fig. 5, the fusible metal standing at 0). The air-tube (B) being placed so as to enter the liquid with its muzzle down- wards, retained great part of the air it originally-contained, though some of it might be driven off by the heat, so as to escape through the liquid. The metal being now allowed to cool, and to fix round the cradle and ramrod, the air remaining in the air-tube was effectually confined, and al] was held fast. The barrel being then filled to the brim with fusible metal, the apparatus was ready for the application of heat to the breech (as shown in fig. 6). In the experiments made at this time, I used a square brick furnace (figs, 7 and 8), having a muffle (7s) travers ing it horizontally and open at both ends. This muffle being supported in the middle by a very slender prop, was exposed to fire from below, as well as all round. The bar- rel was placed. in the muffle, with its breech in the hottest part, and the end next the muzzle projecting beyond the furnace, and surrounded with cloths which were drenched with water from time to time. (This arrangement is shown in fig. 7.) In this. situation the fusible metal sur- rounding the cradle being melted, the air contained in the air-tube would of course seek the highest position, and its first place in the air-tube would be occupied by fusible metal, (In fig. 6., the new position of the air is shown atpq.) At the conclusion of the experiment the metal was gene- rally removed by placing the barrel in the transverse muffle, with its muzzle pointing a little downwards, and so that the heat was applied first to the muzzle, and then to the rest of the 154 Effects of Heat modified ly Compression. the barrel in succession. (This operation is shown in fig..8.) In some of the first of these experiments I Joosened the. cradle by plunging the barrel into heated brine, or a strong solution of muriate of lime, which last bears a tempe- ratute of 250° of Fahrenheit before it boils. For this pur- pose I used a pan three inches in diameter, and three feet deep, having a flat bason at top to receive the liquid when it boiled over. The method answered, but was troublesome, and I Jaidit aside. I have had occasion lately, however, to resume it In some experiments in which it was of conse- quence to open the barrel with the least possible heat *. By these methods I made a great number of experiments, with results that were highly interesting in that stage of the business, though their importance is so much diminished by the subsequent progress of the investigation, that I think it proper to mention but very few of them. On the 3ist of March 1801 I rammed forty grains of pounded chalk into a tube of green bottle-glass, and placed it in the cradle as above described. A pyrometer in the mufile along with the barrel indicated 33%. The barrel was exposed to heat during seventeen or eighteen minutes. On withdrawing the cradle, the carbonate was found in one solid mass, which had visibly shrunk in bulk, the space thus left within the tube being accurately filled with metal, which plated the carbonate all over without penetrating it in the least, so that the metal was easily removed. The weight was reduced from forty to thirty-six grains. The substance was yery hard, and resisted the knife better than any result of the kind previously obtained ; its fracture was crystalline, bear- ing a resemblance to white saline marble ; and its thin edges had a decided semitransparency, a circumstance first ob- served in this result. On the 3d of March of the same year I made a similar * In many of the following experiments lead was used in place of the fusible metal, and often with success; but I lost many good results in this way: for the heat required to liquefy the lead, aptproaches so near to red- ness, that it is difficult to disengage the cradle without applying a tempe- rature by which the carbonate is injured. I have found it answer well, to surround the cradle and a few inches of the rod with fusible metal, and to fill the rest of the barrel with lead. 4 experiment, Substance possessing the Properties of Tannin. 155 experiment, in which a pyrometer-piece, was placed within the barrel, and another in the muffle; they agreed .in indi- cating 23°. The inner tube, which was of Reaumur’s porce- lain, contained eighty grains of pounded chalk. The carbo+ nate was found, after the experiment, to have lost 34.grains: A thin rim, less than the 20th of an inch in thickness, of whitish matter, appeared on. the outside of the mass. In other respects the carbonate was in a very perfect state; it was of a yellowish colour, and had a decided semi-transpa- rency and saline fracture. But what renders this result of the greatest value is, that on breaking the mass a space of more than the tenth of an inch square was found to be com- pletely crystallized, having acquired the rhomboidal fracture of calcareous spar. It was white and opake, and presented to the view three sets of parallel plates which are seen under three different angles. This substance, owing to partial cal- cination and subsequent absorption of moisture, had lost all appearance of its remarkable properties in some weeks after its production; but this appearance has since been restored by a fresh fracture, and the specimen is now well preserved by being hermetically inclosed,. [To be continued. } XXV. Additional Experiments and Remarks on an arti- Jicial Substance which possesses the principal characteristic Properties of Tannin. By Cuarves Harcuetr, Esq. ROR: 8 {Concluded from p, 68.] : § VII. F ROM the experiments which have been related, it appears, that three varieties of the artificial tanning substance may be formed, viz. ist, That which is produced by the action of nitric acid upon any carbonaceous substance, whether vegetable, ani mal, or mineral, . adly, That which is formed by distilling nitric acid from common 156 Experiments and Remarks on a Substance common resin, indigo, dragon’s blood, and various other substances: and, 3dly, That which is yielded to alcohol by common resin, elemi, asa foetida, camphor, &c., after these bodies have been for some time previously digested with sulphuric acid. Upon these three products I shall now make a few re- marks, which I have hitherto postponed, in order that the account of the experiments might not be interrupted. The first variety is that wihiclt 3 is the most easily formed ; and from some experiments which were purposely made, I find that 100 grains of dry vegetable charcoal afford 120 of the tanning substance ; but, as it is extremely difficult com- pletely to expel moisture, or even the whole of the nitric acid which has been employed*, an allowance of about three or four grains ought to be made ; so that after this deduction we may conclude, that 100 grains of vegetable charcoal yi¢ld }16 or 117 of the dry tanning substance. The proportions of the constituent parts of this substance T have not as yet ascertained; but, from the manner by which it is produced, carbon is evidently the base of it, and js the predominating essential ingredient. From § III. experiment F. it also appears, that the other component parts are oxygen, hydrogen, and nitrogen ; for, when the artificial tanning substance was distilled, ammonia and carbonic acid were obtained, exclusive of a very small portion of a yellow liquor, which stained the upper part of the retort, and which, from its tenacity and insolubility in water and alcohol, appeared to be of an oily nature. As I had taken every precaution respecting the charcoal which had been employed, Iwas at first induced to consider the above facts as almost positively demonstrative of the pre- sence of hydrogen in charcoal; but upon further reflection, and upon weighing some of the circumstances which attend the formation of the artificial tanning substance, I still feel ‘on‘this point very considerable doubt; for I have constantly * The most effectual method of expelling the nitric acid is, to reduce the tanning substance to powder, and repeatedly evaporate different portions of fistilled water from it in a glass or porcelain basin. ODL observed, possessing the Properties of Tannin. 157 ebserved, that diluted nitric acid acts upon charcoal more effectually in the formation of the tanning substance than when it is employed in a concentrated state; and it appears therefore very probable that hydrogen may have been afforded by a portion of water decomposed during the process. For, admitting that the new compound (formed by the action of nitric acid upon charcoal) may possess a certain degree of affinity for hydrogen, this, being exerted simultaneously with the affinity for oxygen possessed by nitrous gas, may (espe- cially when the last is in a nascent state) effect a decompo- sition of a portion of water, the hydrogen of which would therefore enter into the composition of the tanning sub- stance, whilst the oxygen would supply the place of part of that which had been taken from the nitric acid. Many of the properties of the tanning substance prepared from coal by nitric acid are very remarkable, particularly those which have been noticed in § III. experiments F and G; for surely it is not a little singular, that this substance when burned should emit an odour so very similar to ani- mal matter, notwithstanding that the tanning substance had been prepared from pure vegetable charcoal. And again, in experiment G, the portion which had not been precipitated by solution of isinglass was, when dried, found to possess a strong vegetable odour very analogous to oak bark, al- though fenktoal is inodorous, and isinglass very nearly so. * Bat, after all, the most extraordinary properties of this sub- stance are certainly those which so nearly approach it to the vegetable principle called tannin; for it perfectly resembles this principle by its solubility in water and in alcohol, by its action upon gelatine and upon skin, by the effects which it produces upon metallic solutions, upon those of the pais and of the alkalis. : The sulphuric and muriatic acids also affect the solutions of it as they do those of tannin; and the only marked dif- ference which as yet has been found in the characters of the artificial substance and of tannin is, that the‘former is pro- duced, whilst the varieties of the latter are more or less de- stroyed by nitric acid. This, for the present at least, must draw a line of separation between them; but we must not forget, 158 Experiments and Remarks on a Substance forget, that even the varieties of tannin * do not accord in the degree of destructibility. The second variety of the tanning substance is obtained from a great number of vegetable bodies ; such as indigo, dragon’s blood, common resin, &c. &c., by digesting and distilling them with nitric acid. It is not, therefore, quite so readily prepared as that which was first described, and its relative quantity, when compared with that of the substance employed to produce it, is less. As resin and some of the other bodies do not afford it until they have been repeatedly treated with nitric acid, and as during each operation nitrous gas is produced, whilst the strength of the acid which comes over is diminished, it. seems * Yshall here venture to state some ideas which have occurred to me on the probable cause and mode of the formation of tannin. Mr. Biggin has proved, that similar barks, when taken from trees at dif- ferent seasons, differ as to the quantities of tannin contained in them.— (Phil. Trans. 1799, p. 259.) “Mr. Davy also observes, “that the proportions of the astringent principles in barks vary considerably according as their age and size are different.” “ That in every astringent bark the interior white bark (which is the part next to the alburnum) contains the largest quantity of tannin. The propor- tion of extractive matter is generally greatest in the middle or coloured part ; but the epidermis seldom furnishes either tannin or extractive matter.” Moreover Mr. Davy remarks, “ that the white cortical layers are compa- ratively most abundant in young trees, and hence their barks contain in the same weight a larger proportion of tannin than the barks of old trees.” — (Phil. Trans. 1803, p. 264.) We find, therefore, ist, That the proportion of tannin in the same trees is different at different seasons. 2dly, That tannin is principally contained in the white cortical layers, or interior white bark, which is next to the alburnum or new wood: and, $dly, ‘That these white cortical layers are comparatively most abundant in young trees, and that their barks consequently contain in the same weight more tannin than the barks of old trees. I shall not make any remarks on the first of these facts, as it accords with other similar effects, which are the natural consequences of the processes and periods of vegetation; but the second and third appear to be important; for they prove thst tannin is principally formed, or at least deposited, in the interior white bark, which is next to the alburnum or new wood; so that in the very same part where the successive portions of new wood are to be ela- borated and deposited, we find the principal portion of tannin. It should seem, therefore, that there is an intimate connection between the formation - —— possessing the Properties of Tannin. 159 seems almost evident that this tanning substance is formed in consequence of part of the oxygen of the nitric acid be~ coming combined with the hydrogen of the original body, so as to form water; and the carbon, being thus in some measure denuded, is rendered capable of being gradually acted upon by the nitric acid in a manner nearly similar to that which takes place when it has been previously converted into, coal. The'colour of the precipitates which this tanning sub- stance yields with gelatine is constantly pale or deep yellow, whilst that of the precipitates formed by the first variety is always brown; I am therefore induced. to believe that. the different colours of the precipitates produced by the varieties of tannin depend on the state of their carbon. When resin and the other bodies were treated as above formation of new wood and the formation of tannin in such vegetables as afford the latter; and this idea is corroborated when the chemical nature of these substances is considered. From experiments made on the ligneous substance of vegetables, or the woody fibre, it appears to be composed of carbon, oxygen, hydrogen, and nitrogen; but of these its principal and essential ingredient is carbon. In like manner carbon is unquestionably the basis and principal ingredient of tannin. Considering, therefore, that both of these substances consist prin- cipally of carbon; that tannin ts secreted in that part of barks where the formation and deposition of new woed take place; and that the quantity of tannin is the most considerable in young trees, and seems therefore to keep paee with their more vigcrous growth, and consequent rapid formation of wood; it appears very probable that those vegetables which contain tannin have the faculty of absorbing more carbon and of the other principles than are immediately required in the formation of the different proximate vege- table substances, especially the woody fibre: that this excess, by chemical combination, becomes tannin, which is secreted in the white interior bark: that in this state it is a principle peculiarly fitted to concur by assimilation te form new wood: that it is therefore subsequently decompesed at the proper period, and is employed in the formation of the new wood: that there is not a continual accumulation of tannin in the vegetables which afford it, as it is successively formed in and with the white cortical layers, and is successively decomposed by concurring to form new wood: and, lastly, that as the veges table approaches more nearly to the full maturity of its growth, when wood is less rapidly and less plentifully formed, so in like manner less tannin is se- creted; for, the fabric being nearly completed, fewer materials are required. Such I am inclined te suspect, from the facts which have been adduced, to be the cause and mode by which tannin is formed in caks and other vegeta- bles; but I make this statement only asa probable conjecture, which may be refuted or confirmed by future observations. : ous described +60 Experiments and Remarks on a Substance described with nitric acid, the quantity obtained of the tans ning substance was much less than when an equal quantity of coal was employed, or even when these bodies had been previously converted into coal in the humid way by sulphuric acid. The cause cf this seems to be, that a number of other products are simultaneously formed, all of which require more or less of carbon as a constituent ingredient, so that, im consequence of the affinities which prevail under the existing circumstances, some bodies by treatment with nitric acid afford but little, and others none, of the tanning substance. The greatest proportion of this substance was yielded by indigo, common resin, and stick lac. The quantity obtained from asa foetida and gum ammoniac was less. Benzoin, balsam of Tolu, balsam of Peru, and dragon’s blood, were inferior to the former in this respect ; so that the development, or rather production of benzoic acid *, ap- peared * The expression “ production of benzoic acid” may appear objectionable, and I shall therefore take this opportunity so observe, that I much suspect the present established opinion respecting the balsams and benzoic acid to be erroneous: for the balsams are defined as bodies composed of resin and ben- zoic acid; consequently the latter, when obta‘ned in a separate state, is consi- dered as an original ingredient or educt. I am, however, inclined to a contrary opinion; for I consider the balsams as peculiar substances, which, although nearly approaching to the nature of resins, are nevertheless different in respect to the original combination of their elementary principles; which combination, however, is with much faci~ lity modified by various causes, and especially by a certain increase of tem- perature, so that a new arrangement of the elementary principles takes placey, part being formed into resin, and part into benzoic acid. Many facts appear more or less to support this opinion; for whether ben- zoic acid is obtained by simple sublimation, or by merely digesting benzoin in boiling water, according to Geoffroy’s method, or by the addition of lime, as recommended by Scheele, or by employing alkalis in a similar manner, nothing positive can be inferred from any of these operations to prove that benzoic acid is obtained as an educt, but rather the contrary, when we re« flect on fligsaffinities which are most likely to prevail under the circumstances of the different processes, and on the variable proportions of the benzoic acid; and although benzoic acid has been discovered in the urine of infants, in that of many adults, and coustantly in that of graminivorous quadrupeds, . such possessing the Properties of Tannin. 161 peared partly to counteract the formation of the tanning sub- stance; but oxalic acid, when formed in any considerable quantity, seemed absolutely to prevent the formation of this substance ; for whilst abundance of the former was obtained from gum arabic, tragacanth, manna, and gnaiacum, not any of the latter could be produced. Common liquorice appears at first to be an exception; but from the smallness of the quantity, and the colour of the precipitate which it produced with solution of isinglass, I am almost convinced that the tanning substance was formed by the action of the nitric acid on a portion of uncombined carbon, which, being in a state approaching to coal, is pro- bably the cause of the blackness of the common liquorice. As the formation of the tanning substance has been my such as the camel, the horse, and the cow, (Systeme des Connoissances Chi- miques, par Foureroy, 4to edit. tom.iv. p.158;) yet all this certainly ap- pears to be in favour of its being a chemical product. I have observed, when benzoin, balsam of Tolu, and balsam of Peru, were "dissolved in sulphuric acid, that a great quantity of beautifully crystallized white benzoic acid was sublimed during digestion; and as it is produced in $0 very pure a state by this singie and simple operation, I would recommend a trial of the process to those who prepare benzoic acid for commerce; but fam not certain whether this mode may prove more economical than those which at present are employed. When dragon’s blood, however, was treated in the same manner with sul- phuric acid, I could not obtain a particle of benzoic acid; nor did I succeed much better when I had recourse to Hinie, according to Scheele’s process; for, although a considerable quantity of the substance was thus rendered soluble in water, yet by the addition of muriatic acid I obtained only a slight appear- ance of benzoic acid, accompanied by a copious precipitate of red resin, not- withstanding that the solution had acquired a powerful and peculiar balsamic odour. But in a former part of this paper I have stated, that when dragon’s blood was dissolved in nitric acid, and afterwards evaporated to dryness, it yielded about 6 per cent. of benzoic acid. Now, if this had been originally present in dragon’s blood in the state of benzoic acid, some stronger évidence of it might reasonably have been expected in cach process; but this not being the case, I am inclined to consider it as produced, and not educed, by the action of the nitric acid on the original principles of the dragon’s blood ; and Iam also persuaded that similar but more general effects take place when benzoin or any of the balsams are subjected to the different processes by which benzoic acid is obtained; so that to me this last seems to be as much a ¢hemical pro- duct as the oxalic, the acetous, and other of the vegetable acids. The succinie acid also appears to be a product and not an original ingre- dient of amber. Vol. 24. No. 94. March 1806. L principal 162 Substance possessing the Propertizs of Tannin - principal object, I have not thought it necessary to enter at present into too minute a detail of other particulars, and have therefore only thus cursorily noticed some of the principal effects produced by nitric acid on the resins, balsams, &c. Those, however, who are conversant with chemistry, will undoubtedly perceive that these effects deserve to be accu- rately investigated ; and that the resins, balsams, gum resins, and gums, should be regularly examined by every possible method, not merely on account of the individual substances which may become the subjects of experiment, but because there is reason to expect that from such an investigation, — medicine, with the arts and manufactures, may derive many advantages, whilst the mysterious processes and effects of vegetation may very probably receive considerable elucida- tion. ; Concerning the third variety of the tanning substance, which is produced by the action of sulphuric acid on the resins, gum resins, &c., I shall here add but hittle to that which I have already stated in the latter part of the second section of my first paper, and in the account which I have lately given of an experiment on camphor. This variety appears to be uniformly produced during a certain period of the process, but by a long continuance of the digestion I have reason to believe that it is destroyed. Bibttancce, such as the gums, which afford mach oxalic acid by treatment with other acids, do not apparently yield any of this tanning substance. ; The energy of its action on ‘gelatine and skin is certainly inferior to that of the first variety, into which however, as we have seen, it may easily be converted by nitric acid. From the mode of its formation there does not appear to be any positive evidence. that it contains nitrogen like the first. and second varieties, and perhaps the absence of nitro- gen may be the cause of its less powerful action ; this I have not as yet ascertained, but it is my intention more particu- larly to notice in a future ones the general properties of this substance. XXVI. 4 ‘ { 163 ] XXVI. A simple and accurate Mode of constructing Gaso- meters for Purposes where uniform Pressure is essential, iy the Application of the Hydrostatic Regulator. By JosepH Strevens, Esq. To My. Tilloch. SIR, HAVE hefewith sent you a drawing and description of a gasometer constructed on the principle of my hydrostatic regulator, described in your twentieth volume, page 289, which, I conceives will be found fully as useful as the most complex and expensive instrument of this kind that has yet been produced. I have endeavoured to be brief in my de- scription, as the reader will easily comprehend the uses and modes of employing the instrument from the descriptions you have already published of other gasometers, and of the hydrostatic regulator already referred to.—l am, sir, Your obedient servant, Garlic Hill, JosEru STEEVENS. March 8, 1806. A tin vessel, A, (Plate V.) of 12 inches diameter and 12 inches deep, is supported by four pillars p, p, p, p fixed at the top into the circular piece of wood m, m, and at the bot- tom into the wood base qq about an inch and a half thick, and hollowed out in the middle to receive the convex surface of the vessel B; on which it is fixed by means of the loops and hooks 0,0,0,0: through the base gq two holes are made to allow the cocks gc to pass, for readily removing B for the purpose of filling, &c.,-though by having a cock near the bottom. it may be filled in its present situation. The vessel B is about 13 inches diameter and 10 deep. d is a collar-of leathers fixed to the vessel A, through which a metal tube de passes, extending down the tube fg to e. 2 To the cock g a recurved tube is fixed, and so bent that it returns and nearly touches the upper part of the gas-holder B. A slip of metal may be placed diagonally under this tube, to prevent the noise of the water while running from A to B. The vessel A being filled with water, and B with gas, in the L2 usual 164 On the Construction of Gasometers. usual manner, (for B is no more than the common gas- holder,) screw in the collar d, shut the cock ¢, and open gy the water will run in until the density of the gas in B is ¢a- pable of resisting its effective pressure, which will always be exactly equal to a column of water whose height is equal to the height of the orifice ¢, of the tube de, above that of the recurved tube in the vessel B: for as the air in entering the vessel A has to counteract a column of water equal to the depth e below the surface, so will the gas in B be pressed with the whole column, minus that part of it above e ; for the superincumbent column above e has no share in the pressure, which may be increased and decreased at pleasure by ele- vating and depressing e, without regard to the quantity of water in A, and which pressure will continue uniform untih the water subsides to the level of the orifice e.—-See the de- scription of my hydrostatic regulator, Phil. Mag. vol. xx. _ p. 289. From the facility with which the pressure im this gaso- meter may be altered, it becomes a very useful instrament in all cases where the blowpipe is used; whether when charged with oxygen gas for the purpose of deflagrating or of deoxidating metals, the combustion of the diamond, or other experiments where intense heat is required; or whe- ther 1t is charged with atmosphere air for miniature, glass blowing, soldering, or the like. It willalso be found useful for filling vessels for a variety of experiments im pneumatic chemistry, as well as for playing jets of flame, &c. Ifa cock, provided with a jet capable of being inclined im any. angle to the horizon, be fixed into the tube fg near g, and the tube de so elevated that the orifice e arrives near or within the bottom of the vessel A, a useful and accurate apparatus will be formed for illustrating the parabolic theory of projectiles ; for, a3 the pressure and efflux is uniform, the horizontal ranges will be equal at equal angles above and below: 45°, and the curve described distinct and well de- fined. An instrument of this kind has been employed in” the Mathematical Suciety’s present course of lectures, and is now in their repository. XXVII. Pro- f 65°°9 XXVII. Process employed to obtain a Black Liquid, invented by Mr. Crarke, an Englishman, and introduced into Commerce; its Use in marking Linen in a solid and dura- ble Manner, and its Application for printing Cottons or Stuffs. By M. Hermestanrt, of Berlin. FE OR these two or three years past, a black tincture has been sold for the purpose of marking linen. A glass polisher and directions for using the tincture accompany the two bottles which contain the ingredients, and the whole is sealed up in a case. , One of the bottles contains the mordant. The other con- tains the ink, which is of a deep brown colour, and which must be well shaken before making use of it, because it subsides when left to rest. The part of the linen intended to be marked must be in the first place impregnated with the mordant, which is al- lowed to dry on the linen. The place which had been wetted is then rubbed with the polisher; an ordinary pen is then dipped in the ink, and the writing is performed on the linen the same as on paper. Neither soap nor any chemical pre- paration will destroy this writing, which, when well dried, is of a very fine black. Having chemically analysed these two liquids, [ am able to give an account of the ingredients which compose them. Preparation of the Ink, Dissolve in nitric acid (aquafortis) what quantity of silver you please. This solution, if the silver has been alloyed with copper, will be of a sapphire blue. In order to separate the copper from the silver add to the solution twelve times its weight of distilled water, or, for want of it, rain water, and suspend in it a thin plate of cop- per. In proportion as this plate dissolves, the silver will precipitate itself, perfectly pure, in the form of a white pow- der. When no more of this powder will precipitate itself, ' the liquor should be decanted. The powder is then washed in a great quantity of water, until the water thrown upon it : L3 is 166 Process employed to obtain a Black Liquid. is no longer of a blue cast, but remains perfectly limpid. The residue, i.e. this powder, well dried, will be silver in its purest state, If this residue weighs one ounce, dissolve as much gum senegal and two drachms of white glue in two ounces of distilled water. Mix this solution with three drachms of lamp-black well calcined in a close crucible. To manofacture this mixture properly, it ought to be tri- turated in a glass mortar. This operation being finished, the solution of silver, di- luted in eight times its weight of distilled water, 1s poured upon the above mixture: the wholeis then well stirred with a spatula, andthe ink is made. ; Preparation of the Mordant. Dissolve two ounces of white glue and as much isinglass, in six ounces of alcohol and as much distilled water. This solution will be made in two days. The B. M.is made use of for the purpose ; and care must be taken to stir the two kinds of glue from time to time. After the whole is dissolved, it must be filtered through flannel, in order to keep back all its mucilaginous particles. The liquid thus filtered, and preserved in a bottle well corked, is then ready for use. | Manner in which the Ink acts. The solution of silver in the nitric acid is nothing else than the composition of the lapis infernalis ; and every one knows its properties in staining the skin, nails, &c. 3 of a black colour. If the linen or tie § is first impregnated with the above mordant, which is an animal substance, the ink may be afterwards applied without spreading, and will com- pletely dye every thread of the part to which it is applied, the mordant having previously partly animalized the fibre of the fabric. Soap, or any other ingredient used in washing, may obli- terate the lamp black, but it never takes out the nitrate of silver; and the object proposed is therefore perf fectly well attained. Application Production of Muriatic Acid by Galvanism. 167 Application of the Ink for printing orange Cotton and other Stuffs. We may easily conceive that this ink may be employed with advantage for printing cloths of a white, yellow, or rose ground, or any other clear colour. The cloths or stuffs intended to be printed in this manner, require no other preparation than to be dipped in a solution of parchment or isinglass ; and after they are dried they must be rubbed with a glass polisher. The ink must be thickened for this purpose with a greater quantity of gum senegal, and then applied upon the cloths or stuffs in the usual manner by means of wooden or metal stamps. ~ Three or four days after this operation the stuffs must be first wasbed with a great quantity of clear water, and after- wards with soap and water, which will make them appear of a finer black. i SS XXVIII. Letter of Messrs. Civs1 and PeTRINi to Pro- fessor Paccu1ant, of Pisa, on the supposed Production of Muriatic Acid by Galvanism *, W ue professor Simon f, by insulating the action of the positive pole of the electrical column under water, obtained oxygen gas and an acid as the result of his analysis; and when he recognised in this acid all the characteristics of the muriatic.acid, he supposed that it might be produced by the muscular fibre which he had substituted in the place of the metal wire communicating with the negative pole of the column; and he went no further than imagining that he shad only obtained a result new, interesting, and agreeing extremely wel with the most luminous facts of pneumatic chemistry. ; It was reserved for you to trace this result a little further ; and your repetition of the experiment produced this new and * Abridged from Annales de Chimie, tome Ivi. p. 269. + Annales de Chimie, tome xli. p. 106. L4 important 168 On the supposed Production important truth—<‘ that hydrogen is susceptible of different degrees of oxygenation.” The discoyery of the nature of the muriatic acid ought to coincide with that of the different degrees of oxygenation of which hydrogen is susceptible. <¢ Of al] the substances known, says the ilJustrious Ber- thollet in his Chemical Statics, ‘* there is none of them, with the exception of hydrogen, which, at an equal weight, can combine with a greater quantity of oxygen, making its wharacteristic properties disappear, while the substance it- self also loses the properties which characterize it. These facts prove that the acid property required to saturate deter- minate quantities of alkali, is not in proportion to the quan- tity of oxygen which combines with a base; but that the more it is condensed, the stronger, in consequence, 1s the action which it evinces; the less it gives of acidity at an equal quantity, because the free acid property which it com~ municates by its affinity is diminished in consequence of this action. Thus water, exhibiting neither the property of oxy- gen nor of hydrogen, we may conclude that these two sub- stances are combined at the term where the reciprocal affinity exercises the greatest effect, and when they are in a similar state to that of a neutral salt, in which the acid and alkaline properties are equally become latent ; having experienced by their combination a condensation by which their volume ig reduced to 0°0002. In the acids the qualitics of oxygen pre- yail ; in inflammable liquids those of hydrogen are predomi- nant in such a manner, that in the first combinations the ? oxygen experiences a degree of saturation Icss than in water, and in the latter it is the hydrogen which ts ia this state.” After this opinion of one of the most celebrated chemists of Europe upon the phenomena relative to the combinations of oxygen, we need be no longer surprised to obserye hydro- gen passing, in your experiments, to a state of acidity, by aba indoning 2 part of the oxygen which saturates it. We et homage to truth j in adopting entirely your ideas upon the decomposition of water by means of the electrical exciter. They coincide too exactly with the luminous prin- ciples of the ‘ Chemical Statics”? to doubt it for a moment. Occupied of Muriatic Acid by Gaivanism, 169 Occupied in repeating some experiments concerted with you, we were anxious to determine the proportions of the elements of the muriatic acid. We introduced into a glass tube, in- tended to contain the water which was to pass to the state of muriatic acid, a solution of carbonate of soda or of potash. We closed the upper extremity of the tube, which was tra- versed by a gold wire communicating with the positive pole of the column by a crooked capillary tube, which entered under a little bell glass filled with a solution of caustic soda, and inverted in a little cup containing the same liquor. The oxygen, which liberates itself from the water, deter- mines the production of a certain number of particles of muriatic acid, which take the place of a greater or less quan- tity of particles of carbonic acid in the carbonate of potash or soda according to the amount of their capacity of satura- tion. The oxygen gas and the carbonic acid gas pass through the tube into the bell glass of the pneumatic apparatus; and this latter, absorbed by the caustic soda, leaves the oxygen gas alone. It is evident that the neutral muriate of soda or of potash contained in the tube which transmits the elec- trical fluid (and which may be easily separated from the car- bonate of soda or of potash that may remain there, by de- composing the latter by the acetic acid, and taking up the acetate by means of alcohol) indicated the quantity of mu- riatic acid which was there formed, while the air which may pass into the bell glass of the pneumatic apparatus announced the quantity of oxygen which a mass of water, equal to the amount of the weight of the acid formed, and of the oxygen gas obtained, must lose in order to be converted into muriatic acid. The same results may be obtained by a method much simpler and more rigorous, by substituting in the pneumatic apparatus mercury in the place of caustic soda. In this case, a mixture of carbonic acid and oxygen gas will be ob- tained in the bell glass of the apparatus; and when the quantities of soda or potash which the carbonic and muriatie acids require for their saturation are exactly known, the quan- tity of carbonic acid gas liberated necessarily indicates that of the muriatic acid, which has assumed its place in the tube 170 Decomposition of Water by Galvansim. tube through which the elastic fluid passes to form the mu- rate of badd or of potash. We have reduced to a very simple formula the general expression of the results ofall the expe- riments of this kind. - If, for example, the muriatic acid necessary to neutralise the potash or soda freed from car- bonic acid is a quantity expressed by m, and that the oxy- gen gas obtained is represented by x, m+ 2 will be the weight of the water decomposed, which we express by P: thus if the oxygen contained in P equals 0:85 p, then the oxygen which contains mm is equal to 0°85 p — 7. XXIX. On the Decomposition of Water by Galvanism, - by Joun Curssertson, Esq. DEAR SIR, To Mr. Tilloch. I HAD, by some means, overlooked that paragraph in your valuable Magazine (vol. xxiv. p. 265.) wherein you mention you bad been informed that I kad repeated the experiment on the composition of muriatic acid by Galvanism. I did not know you had mentioned it till I was applied to for such ai apparatus as you had mentioned. Your information, however, was not perfectly correct :—I performed the expe- riment, but did not intend it for publication till I had re-. peated it in a more accurate manner; I only did it to try what would be the consequence when the experiment was performed in such an incorrect manner as any person might be able to repeat. The water which I used was not distilled; intending, if I found at the termination of the experiment the remaining water to possess any other properties than that which it had before the process, to hold it a sufficient encouragement to undertake an accurate repetition. T found during the process that the gold wire let fall from its surface something that had the appearance of pieces of black rusty metal, and the wire appeared at places much corroded. The platina wire let fall a small white cloud near the end of the process. When one-half of the water had disappeared, the remaining portion, by the usual tests, showed signs of aci- dity. Decomposition of Water by Galvanism. 17 dity. Two days before the experiment ended, I placed that end of the tube which had the gold wire at the upper end of the trough, and very soon the platina which had remained bright became black, and, when magnified, had the appear- ance of black powder covertiyg its surface, from the end to the height of the gold wire. The glass tube was in the form of the sketch sent herewith (Plate V. fig. C.) The lines on the inside represent the two wires; al the gold wire, and ced the platina wire. This result made a repetition necessary in a more accurate manner. Accordingly, I took another clean glass tube bent in the same form, but I substituted, instead of the gold wire ab, a platina wire, so that both wires were of the same metal, ~ and introduced distilled water. After this apparatus had stood with its end @ in connection with the zinc end of the trough three days, the short platina wire assumed the colour of gold, and the long one began to grow black from the lower end to the height of the short wire, and continued so for the space of three weeks. When about one-third of the water had disappeared, I connected the lower end of the tube with the copper end of the trough, and in the space of one day the black powder left the long wire perfectly bright, and the short one became black. In the space of two days that por- tion of the long wire to the height of the short one obtained a yellowish gold-lke tinge. Both remained so for three days ; when I placed them in their first situation: the black powder left the short wire, and the long one became black T im- mersed in the remaining water a slip of blue test paper 5 the colour was changed; so that I make io doubt but that, when the operation is continued till half the water disappears, it will give as strong signs of acidity as the former. You will observe that the ends of the wires are placed pa- rallel to each other; I found that situation to be most fa- yourable to. the production of gas: perhaps, if they were placed with their ends. opposite each other, the change of colour would not take place. Tam respectfully yours, No. 64, Poland-street, Jounx CuTHBERTSON. March 22, 1806. XXX. No- ! XXX. Notice of Experiments made by the Galvanic Society of Paris on the Discovery announced by M, Paccuiant of the Composition of the Muriatic Acid *. As soon as the Galvanic § ociety was informed that M. Pac- ehiami announced that he had obtamed muriatic acid by taking from water a part of its oxygen, the society’s first care was di- rected to endeavour, as well by means of electricity as of Gal- vanism, to confirm this discovery so important to science. M. Pacchiani having solely employed the Galvanic pile, the members determined to employ in theit experiments the same agent, in that manner which appeared to them the most convenient and proper; and, above all, which might give results the least susceptible of objections. First Experiment. They tock a piece of new glass tube of 6:08! parts of a meter in length, and 0°009 parts of a meter of interior dia- meter. One of the ends of this tube was closed by the lamp; to the other a capillary tube was joined (by fusion), bent so as to come under a bell glass. At the upper part of this tube, and at an equal distance from the junction of the ca- pillary tube, two holes were punctured at the lamp through the solid glass, by means of which apertures there were in~ serted into the interior of the tube, at a very little distance from its lower extremity, two, bits of gold wire of the stand- ard 0-976 purity, and about 0:0005 parts of a meter in dia- meter, disposed so as not to touch each other, and not to bear against the inside of the tube. These openings were afterwards closed by the lamp. The tube and its capillary addition was filled with pure distilled water. The whole was fixed with bees’ wax upon a piece of glass placed upon the middle of a horizontal Galvanic pile of 52 pairs of square plates of 0°108 parts of a meter each side. These plates were separated by bits of leather, the interstices among which were filled up with very pure sand moistened with a solution of muriate of soda. The capillary tube being plunged in a * Trom Annales de Chimie, tome lvi. tub On the Composition of the Muriatic Acid. 173 tub of water, its extremity entered below a bell class filled with the same fluid. ‘The two gold wires being then placed 1 communication with the two poles of the pile, its activity was immediately manifested by the disengagement of gas in a string of very perceptible bubbles coming from the mferior extremity of each of the gold wires, but in a much greater quantity from that connected with the copper pole. The pile was kept in action, with very little interruption, from the sth Thermidor to the 1ith of the following month. After any interruption whatever, the activity was immediately reproduced by the agitation of the wires communicating with the poles of the pile. It was also remarked that the activity of the pile was constantly stronger from mid-day till four o'clock, when it began to decline. On the 11th Fructidor the apparatus was dismounted, after having been during | 34 consecutive days in action, and im an activity of disen- gagcement which may be considered as having been con- tinual. The water was then diminished by one-half its vo- lume. It had lost nothing of its limpidity. The extremities of the gold wire, from which the disengagement of the gas took place in the interior of the tube, were oxidated; the one corresponding with the zine pole of the pile was most oxidated. The whole of the gas obtained and collected during the experiment was about 793 cubic centimeters. The liquid remaining in the tube was examined with care. Jt produced no kind of taste upon the tongue, nor any action on tinctures of turnsole and brazil-wood, nor with the solution of nitrate of silver. The society. proceeded afterwards to the trial of the gases disengaged by the action of the pile. After: having intro- duced one measure of it into the eudiometer, of Fontana, they made pass into it an equal quantity of nitrous gas made expressly for this experiment. There was an absorption of 77 two hundredth parts upon the volume of the two measures. In order to ascertain if by this absorption all the oxygen the gases contained had entered into combination, a second measure of thé same nitrous gas was introduced’ into the eudiometer after this absorption. It experienced no dimi- nution’ of volume. They tried to estimate by comparison : 3 the 174 Ori the Composition of the Muriatic Acid. the quantity of oxygen which could indicate the absorptiory produced by the introduction of the first measure of nitrous gas, by trying atmospheric air in the same manner. °“They consequently introduced one measure into the eudiometer and one of the same nitrous gas. The absorption was 55 two hundredth parts. By considering this absorption as the ef- fect of the combination of the nitrous gas with the quantity of oxygen vas corresponding to 0°22, which atmospheric air contains of it, they concluded that the absorption of the 77 two hundredth parts, produced with the gas of the pile, re- presented proportionally the combination of the same nitrous gas, with a little Jess than 0°31 of oxygert. It was then ob- served that, the measures of the gas having been separately and successively introduced into the eudiometer, it might have happened that they were .not intimately enough mixed together, and that, consequently, the absorption might not be complete. It was thought more convenient to make the gases pass at first by separate measures under a bell glass, and afterwards to introduce the whole volume of them into the endiometer. The preceding experiments having been repeated in this manner, there was, with the gas of the pile and: the nitrous gas, an absorption of 92 two Puadralte parts in place of 77 resulting from the same tria} by the former mode ; and with atmospheric air and the same nitrous gas, the absorption was 68 two hundredth parts in place of 55 : there results from it always in the same proportion of 0°22 of oxygen contained in atmospheric air, a propostional indica- tion of about 0°30 of this gas in that of the pile. It was tried again with the eudiometer of Volta, by introducing into it a measure through which the electrical spark was made to pass z the trial was repeatedly made upon two, three, and four mea- sures, and always the absorption resulting from the inflam- mation by the electric spark gave the same. indication of about 0°30 of oxygen. Second Experiment. Two grammes of distilled water were placed in a glass tube bent in the manner of a syphon. ‘Two wires of the gold of commerce, of about 0:0002 parts of a meterin diameter, were introduced On the Composition of the Muriatic Acid. 175 introduced into this tube, plunging them into the water at about 0-006 parts of a meter distant the one from the other, This tube was placed upon a horizontal pile of fifty double’ plates of about 0°98! parts of a meter in dimension upon each side. The intervals were filled with dry sand, moistened with river-water acidulated with about a sixtieth part of nitric acid. The gold wires having been placed in communication with the two poles of the pile, the water in the tube assumed, from the first day, a reddish brown colour upon the side of the copper pole, and the wire which joined it was covered with a coating of a deep brown oxide of gold. The wire corresponding with the zinc pole did not assume the same colour. The gold was gradually dissolved, and was preci- pitated, as well as a portion of the silver alloy. This preci- pitate presented to the magnifying glass, upon almost the whole Jength of the tube, needle-formed crystals. The wire corresponding with the zinc pole was entirely cleared: of the gold which it contained, and it was now nothing else than a silver wire of extreme tenuity. There was very little gas disengaged from either extremity of the wires. The water was only diminished a fifth part of its volume. The pile was in full activity from the ¢8th Messidor to the 8th Fructidor: it still indicated to the last day, by means of the electro-mi- crometer (simplified and perfected by one of the members of the society upon the one constructed in Germany, described in the Journal de Physique tor the month of Messidor, year 13), atension of 840 degrees. The liquid residue pre- sented with the different re-agents no mark of acidity, it only had a metallic taste. The Galvanic Society, by examining principally the re- sults of the first experiment, as relating more particularly to the fact announced by M, Pacchiani, considered that, by keeping account of the small quantity of oxygen which had produced the oxidation of the extremities of the gold wire, they might estimate the total quantity of oxygen contained in the gas of the pile; and, as they found it very nearly in the same’ proportion that oxygen gas enters into the forma- tion of water, the society believed they might conclude that the only effect of the action of the Galvanic pile, during-the whole 176 ‘On the Composition of the Muriatic Acid. whole continuance of the experiment, had been the decom- position of a portion of the water employed, and the sepa- ration, in a pure state, of the oxygen and hydrogen gases of which it was formed. The society is therefore of opi- nion, that M. Pacchiani is deceived respecting the nature of the acid which he announced he had obtained, or that this acid may have come from some animal or vegetable sub- stance employed iu his appatatus. They do not hesitate to declare that to the apparatus employed by themselves they give the preference, as the simplest and most remote from any foreign influence ; and they do not believe that it is pos- sible to produce any thing by the action of the Galvanic pile, except the decomposition of a greater or less propor- tion of the water submitted to its action. XXXI. Extract of a new Letter of Dr. Francis Pac- cHIANI, Professor of Natural Philosophy in the Univer- sity of Pisa, to M. Fapront, upon the Composition of the Muriatie Acid*. Tae efforts which the best naturalists have hitherto made to explain in what manner water is decomposed by means of the electrical column, and to give an account, with pre- cision, of the important questions which have arisen on this subject, demonstrate that the principles from which they set out, in order to attain their object, were far removed from being an immediate result of facts clearly ascertained, and that they were given to the public without regard to the mductions of science. When hypotheses are established by analogy, if they de not perplex the mind of the philosophical observer, they eertainly will be of great assistance to him in his research after truth ; hut when they are too hastily erected into prin= ciples, instead of aiding the judgment, they hinder it from displaying itself, and arriving at those sublime truths which are the object of its labours. * From Annales de Chimie, tome lvi. I have On the Composition of the Muriatic-Acid. 177 I have already sufficiently indicated the method Ifollowed in order to. generalize the results I announced ; and I have demonstrated that not, only, gold and platina, but all. the metals and metallic bodies, in short all substances, proper for decomposing water, as soon as they| are traversed: by an electrical current strong-enough to disengage oxygen, have the property of converting water into oxygenated, muriatic acid. This change of nature, this metamorphosis. (if may be permitted so to-express myself) of water, fills-wath asto- nishment the philosopher who contemplates it,) and whe comprehends the useful consequences which may be derived from it. ; For a long time I have been occupied with this subject, and this result enters into the course of experiments which I made and communicated to M. Viltosio Fossombroni. But have the people who repeated my experiments read my let- ters with a tranquil spirit, laying aside all the hypotheses already received? . Did they make use of the method which I indicated ?—Certainly not. My assertion is so true; that some celebrated chemists, in spite of what I observed in my letters, introduced into the apparatus two metallic wires, making one of them commu- nicate with the positive pole, and the other with the negative pole of the electrical column. How is it possible to obtain, by such a method, the conversion of the water into oxyge- nated muriatic acid?» It.is a:fact recognised: by every na- turalist, that the wire which communicates with the positive pole disengages pure oxygen, while the other which com- municates with the negative pole disengages from the water very pure hydrogen ; itis likewise equally obvious, that the two gases into which the water’ gradually converts: itself, de- velop themselves in such a:proportion, that if they lose their elasticity they will again recompose the same volume of water, equivalent in weight to that of the two gases. I ask, at present, How, after these facts, it could be pre- tended that the liquid whichremains from the decomposi- tion could convert itself {into oxygenated muriatic acid? But Jet us proceed a step: further: the molecule of water which are deoxygenated +hy the contact of the wire of the Vol. 24, No. 94. March 1806. M positive 178 On the Composition of the Muriatic Acid. positive pole, being deprived of their elasticity, could not they combine themselves immediately with the other mole- cule of water abandoned by hydrogen in the neighbourhood of the wire of the negative pole of the electrical column, since they areequally deprived of elasticity? The thing is self-evident’: in fact, if molecula of oxygen and hydrogen deprived of elasticity, and in the necessary proportions to form water, could enter into immediate combination and not form water, it would be impossible that water could exist at all. These conisiderations did not escape the celebrated Hum- boldt and Gay-Lussac: they understood extremely well that in the experiment of the English chemists the water could not be oxygenated and hydrogenated but for a single mo- ment alone; seeing that the total absorption of hydrogen on one side, and of oxygen on the other, shows that the water is really neither hydrogenated nor oxygenated ; because, in order to become so, it would be necessary that it should absorb one of the two gases in a proportion different from that required for the composition of water: then, if it ab- sorbs these two gases in the proportion indicated, we ought to conceive that the properties of one of these would be neutralized by those of the other, and that consequently, in the experiment quoted, the water might hydrogenate or oxygenate itself fora single moment, but that it could not remain in this state in a permanent manner, for the reason already mentioned. ~ But to return to our subject, which is to resolve the pro- blem of the solution upon which the conversion of water - into oxygenated acid depends. A volume of- water, distilled and deprived of air, being given, decompose it in sac! a manner that the element of which it ought to clear itself gradually may be very pure oxygen. 34 Solution, Take a glass tube of any form you please, provided that it has two orifices, the one small and rounded, the other of "a diameter large enough to introduce the water without trou-_ ble: through the first of these orifices make a gold wire ct se , val ‘ pass On the Composition of the Muriatic Acid. .179 pass and seal it up with wax; then fill the tube with di- stilled water, and place in it two or three layers of white linen moistened ; seal it up by fixing the linen to the ex- tremity of the tube. Plunge the tube by this last extremity into a vessel containing very pure water. By means of se- veral moistened slips of spongy paper make the water of this vessel communicate with the negative pole of a column sufficiently energetic; and, finally, make the gold or platina wire communicate with the positive pole of the electrical column. The energy of this column being proportioned to the number of pairs of metallic plates, to their state, and to that of the humid conductors, would be, as is well known, proportioned to the capacity of the tube which contains the- water under experiment. As soon as the circle is completed, it will establish an uninterrupted circulation, and by this means the water will gradually clear itself of oxygen, passing it off by the wire of gold or platina, This astonishing change of water into oxygenated mutiatic acid creates an agreeable surprise in the mind: Felix gui potuit rerum cognoscere causas. After having resolved this important problem, I proposed another to myself, which: was as follows : A volume of water, distilled and freed. as rhuch as possible from air, being given, it is proposed to extract the hydrogen, from it. Solution. Take a glass tube with two orifices, the one straight and without any sharp edge, the other with a stopper, and of a diameter sufficient to introduce the distilled water without trouble. Introduce through the smallest orifice a wire of gold, platina, or other metal, and seal it hermetically with wax. Fill this tube with distilled water freed from air, close the other orifice with fine linen moistened with water folded - three or four times ; plunge the tube on the side of this second orifice into a vessel containing pure Water; plunge into this water slips of spongy paper which communicate by the other extremity to the positive pole of the electrical pile. Finally, make the metallic wire communicate with the negative pole of this same pile. 7 being done, a M2 circulation 180: Royal ‘Society of London. circulation of the electrical fluid, as is well known, wiik commence; which gradually makes a quantity of air escape near the metallic wire, which, ‘being analysed, is: found: to be almost wholly pure hydrogen. ~By ‘this’ new method of: decomiposition we obtain water — very much oxygenated, as is positively proved by the ex- _ périment f Have given in my; Opzscales. © If that which several philosophical physicians iat asserted be'true, thatoxygen is an excellent remedy in. cutaneous dis- eases, the philanthropist may have) recourse to the electrical column to obtain! oxygenated water, and make numerous experinients~usefal to society. In short, what simpler ve- hicle ‘could we choose, by means of which to introduce. oxy- ge? intorthe human bodys tha a liquid so necessary to lite? =—— e eel : 5 : " 3 _XXXIL. Proceedings of Learned Societies. “ROYAL SOCIETY OF LONDON. | spear ote. The Right Honourable Sir Joseph Banks, Presi- dent, in the chair.—A paper by Mr. Home, ‘on a particular affection of the prostate gland,” was read. It was illustrated bya. -drawing exhibiting minutely the situation and figure of this newly nites ane or rather peculiar nipple- formed elongation of a part of the substance of the prostate gland protruding against the bladder, This disease, which so pain~ fully, affects the bladder, has hitherto been irremediable, chiefly from its true cause not being, known; and it is hoped that this physiological discovery may be of incalculable advan- tage towards relieving the, sufferings of patients supposed to be labouring under the. effects of calculi and other -urinary diseases. ‘March G. The President in the chair. —The reading of a b communicatian: “from Dr. Herschel, & on the quantity and velocity of the s solar motion,” was commenced., March, 13, The, President in the chair. —Continuation of the : above paper,, much af, which was of a pature not to ri ready being, mathematical tables of the relating distances of eM the. - Society of Antiquaries. — is! the fixed stars. The observations contaimed in this paper are in continuation of a former communication from the author on the direct motion of the sun, and illustrate, with his usual ingenuity, the causes of the sidereal motions ap- plied to stars of six different magnitudes. March 20. The President in. the chair—A_ paper Loy J. Mendoza Rios, esq. was read, explaining the propertics © and use of an instrument for dividing circles. SOOIETY OF, ANTIQUARIE Se. Feb. 27. The right honourable the earl of Tiaras ne pie= sident, in the chair The indefatigable Mr-Lysons furnished some very Curious extracts. from ihe Tower Records.of Ed- ward I., in which it appeared sthat Edward: was: extremely attached to different kinds of sports.and pastimes, and parr ticularly to a. game with ¢ards which. he brought from Pa- lestine after! his:croisade, where painted: figures.on paper had been in use long before. the reputed discover y of cards.by.a Frenchman in the 4th century. This fact: is worthy, of attention; as it would lead to the discovery of the real origin of several other things, which bave-been introduced by the same means into;Europe, and which ‘have jatterly passed, but erroneously, for French discoveries.» it will be pre- membered, that Edward; returning from the eroisade, came through France,» where she was, treacherously detained a3 a hostage, and: during which) time he contributed very smate- rially to disseminate the ‘atts and civilize his then faithful subjects of Guyenne., it is also known that the Moors used something nearly similar to cards for amusement at Cordova and Granada, and it is most probable that they were of Cary thaginian or Pheenician origin. Like almost all the utensils of civil life, games with cards have doubtless originated in commercial and mercantile countries. 8 » J.P. Malcolm, esq. exhibited to the society the core of a Daihy that was found in St. Paul’s Church-yard, nearly nine feet below the surface of the ground. This bone was sup: posed to have belonged to some of the anima!s sacrificed in the days of heathen superstition, as it is alleged that the site * of St. Paul’s was antiently’a place where tle Romans offered M3 up 182 Society of Antiquaries. up sacrifices to their gods.. This exhibition and letter pro- duced such a general emotion, that the venerable locks of the hoary-headed antiquaries shook with laughter, although the very learned author did not pronounce whether the bone which he exhibited had belonged to a red or a white bull! ~ On the durability of a most porous bone Mr. Malcolm had certainly never reflected, otherwise he would not have sup- ~ posed it above 1500 years old! Several historical documents, extracted by Mr. Lysons, were read, relative to the principles and conduct of the last Welsh prince of Wales (in 1260), and his reluctance to submit to the English domination. March 6. C. Orde, esq. vice-president, in the chair.— Some of the antiquarian friends (not natwralists, indeed,) of a learned lady, having expressed their doubts if the misletoe grew on the oak, she ordered a search to be made, and ascer- tained the fact, which was cOmmunicated by lettér to the society, and confirmed viva voce by one of the members, who saw this parasitic plant attached to an oak branch sus- pended in the hall of Berkeley castle. Our industrious an- tiquaries seem to have forgotten that the wiscus quercinus, or misletoe of the oak, has been used in medicine. An interesting Jetter to the president from the reverend S. Weston, B. D. was read, containing a description of a hitherto unknown brass coin of one of the states of antient Greece. On one side was a head, and on the other a bunch of grapes well executed. The following letters only were visible—HY¥; the coin having been cut into an oval form.. The opinions advanced respecting it seemed to rest on mere conjecture. March 20. The right honourable president in the chair.— A mining instrument, found in an old mine near Castleton, Derbyshire, was exhibited. It 1s of the figure of a common gouge used by carpenters, about a foot long and an inch in diameter. The upper part of it is covered with spar, which is evidently formed upon it, and adhering to it on all sides. It is thought that this mine has not been wrought since the days of the Saxons; but no opinion was given of the pro- bable antiquity of the instrument, which is unquestionably much ’ d Galvanic Society, Paris. 183 much more modern, and may have been used long since the mine in which it was found has been worked. Nor is the formation of spar one of the slowest processes of mineral aggregation. GALVANIC SOCIETY, PARIS. The following account of the proceedings of this society, during the years 1804 and 1805, was read at its sitting on the 6th of February 1806. The pile of Volta has been considered in different points of yiew, and has experienced several new modifications in its construction. One of the correspondents of the society, M, Marechaux, has formed a pile of nine disks, composed of zinc, and copper, separated by rounds of dry blotting paper. Cords of silk supply the place of the glass tubes in. the ordinary apparatus, and hold it suspended to a hook. The pile thus constructed produces very sensible effects. M. Marechaux thought he remarked, by means of this ap- paratus, that the electrical tension of the pile increases and decreases in proportion to the electrical state of the air, and that its action is stronger the more the air is charged with hurnidity. A new apparatus, to which the name of the Galyanic chain has been given, has been invented by M. Struve. This chain is composed of several double cones, one of copper and another of zinc, and so on alternately, soldered together by their bases. To the point of these cones is an- nexed a hook, which serves to join together a greater or less quantity of these double cones. Linen or cotton is placed between these latter, in such a manner, however, that the extremities are in contact with each of the extremities of zinc and copper. The chain, thus disposed and saturated with muriate of soda, is instantly in a condition to operate. It is, according to the author, less oxidable than the ordinary apparatus, and its activity is triple; a chain of 15 or 20 of these cones having as much energy as a pile of 50 or 60 disks. It was very difficult, with the straw electrometer of Volta, and even with the electric balance of Coulomb, to appreciate : M4 the ‘184 Galvanic Society, Paris. ‘the feeble ‘electrical tensions of the Galvanic pile without having recourse to the condenser; an instrument variable in its effects, and:of which the results are often deceitful. To remedy this inconvenience, different electrometers have been presented to the society, one by M. Volf, and another by count Sternberg; but none of these seemed to unite so many advantages as one produced by M. Marechaux, ‘as im- proved by M. Veau-de-Launy. » Messrs. Nauche, Graperdn, and Baget, have ascertained that the Galvanic action is augmented, in the first place, when the pile is exposed to a'high temperature; secondly, when it is phinged into flame, ‘or into oxygen gas, or-car- bonic acid gas, &c.; thirdly, they ascertained that the ef- fects of the pile are not transmissible in vacuo*, or that they ‘are then scarcely perceptible even by means of a condenser. By analogotis experiments M. Edmond de Barrey’ ascer- tained the non-transmission of Galvanisin through smoke. “Naturalists having announced opposite results from their experiments on the conductibility of flame, M. Izarn took up the question anew. He has ascertained that flame in- terposed in the Galvanic chain perceptibly transmits the ef- fects of the pile. This he discovered by its action on frogs. This conductible property is nevertheless very feeble, the frogs being excited in a much mére oie manner when no flame i is interposed, “The diamond, which several modern chemists regard as pure carbon, is, according to the experiments of M. Brugna- telli, a non-conductor of Galvanism; although it is ascer- tained, from the labours of M. Curtet, of Brussels, that the oxide of carbon is one of the very best conductors. , M. Herman, of Berlin, has examined the properties of different substances employed as Galvanic conductors ; and has divided them into insulated bodies, into perfect and im- * Mr. W. H. Pepys ascertained, a considerable time ago, that the action of the pile is augmented by placing it in oxygen, and destroyed when placed in a vacuum; but, instead of the effect not being transmissible through a va- cuum, he has ascertained that the metals may be deflagrated in vacuo. The metals, of course, are not oxidated—they are only volatilized, light being given out during the process,—Enit, perfect ae Galianic Society, Paris. 185 perfect conductors, and dnto uai-polar and bi-polar bodies, according as their conductible property manifests itself at both, or ratily at one of the extremities of the pile.) © #> The theory of the decomposition of water by means of the apparatus of Volta has commanded the particular attenwon of the society. scl ag Q “One of the ‘honorary siveratonves M. (paises maidicad this decomposition in a very strong glass ‘tube-full of water and hermetically sealed, by means of a brass cap seréwed on with leather between the joints. The result of his experi- ments was, that the Galvani¢ a¢tion takes place as’ wellin the closed tube as in an-open one, ‘or one only partly filled with water; but that in the first, the water, in order:‘to make room for the bubbles of the gas produced by decomposition, penetrates ‘through the pores of the brass-or greased leather which serve to-close the tube, and/makes'its agpnnen sams spite of every obstacle. >! - , The reported formation of muriatic acid sy the ‘decompo- sition of water presented a new problem for the;solution‘of the society ; and numerous experiments have been made in order to ascertain the facts announced by M. Pacchiant. The results, however, liave not yet been similar to his); but the society is still occupied in pursuing the same eit ments. M. Marum produced the dectinotizion of water by means of the grand electrical machine in the Teylerian museum: the two, wires of platina eniployed in the experiment pro- duced the liberation of a mixture) of oxygen’ and hydrogen gases ; and he was not able to obtain them Neal as he did with the pile. Gautherot, whose loss every naturalist deplores, was the first who suggested the idea of accumulating the Galvanic fluid, and preserving it in apparatus where it ‘was not spon taneously produced. He accomplished this by a method»at onee simple and ingenious. bo 2 ** If we place,” says he, “ina bottle of salt water, closed with a linen stopper, the, extremities of two wires‘of platina, which traverse this'sdme stopper without touching one an- other ; and if we make the outward extremities of these two wires Ss 186 Galvan Society, Paris. wires communicate with the two poles of the pile; this communication may be interrupted, and yet the wires will excite a decided taste, and perhaps a slight commotion, and will even produce the decomposition of water. This experi- ment demonstrates the presence of the Galvanic fluid in an apparatus by no means proper to form it. “ If we plunge the two extremities of a single wire of pla- tina in the extreme cups of the disk apparatus, and if we bring these two ends near together, but without meeting, and carry them to the mouth, we experience a Galvanic taste, the more decided in proportion as the diameter of the wire is more considerable.” The discovery made by this author, and the importance sf which he has represented, ought to become, to use his own words, * the source or basis of several other experiments, and concur, more than any other, to the ssitianiad of the theory of this new branch of physics.” Treading in the footsteps of Gautherot, M. Ritter has pro- ceeded a step further, in ascertaining that bodies which form @ part of a Galvanic arc, pass, npon quitting it, into an op- posite state from that which they formerly held, in such a manner, that the side, which during the communication was positive, becomes negative when it ceases, and so on, vice versd. This remark conducted him to the construction of a secondary or charging pile,—a happy invention, which forms an epoch in the history of Galvanism. This pile is formed of disks of a simple metal, such as copper, and of an equal number of cards well saturated with water. Jtis raised on an ordinary support, by alternately laying on the disks of copper and the rounds of wet card. The whole is kept steady by means of glass rods. | The pile, constructed in this manner, by iiself produces no perceptible phenomena; but placed for a few minutes in communication with the Volta’s pile, it acquires the proper- ties of that pile, displays an electrical tension, evinces com- motion, and gives sensations of light, taste, and other Gale vanic phenomena in the same manner. The society resolved to ascertain the effects of this se- condary pile, with all the modifications which its construc- tion University of Gottingen, Bc. Ge. 187 tion presented ; and although they obtained results a little weaker than those announced by Ritter, they do not hesitate to regard his labours, as well as those of Gautherot, as the most fortunate experiments which have been made since the invention of the pile of Volta; and they acknowledge that both of these philosophers deserve well of science—the one for having paved the way, and the other for having given a grand discovery to the world. : The effects of Galvanism in medicine have been also tried, but with: little success hitherto. In some cases of asphixia it did harm; and out of an immense number of applications - to deaf and dumb patients, both naturally and accidentally so, only two scemed to have derived any benefit. Several poisons having evinced the Galvanic excitability, while others remained unmoved, M. Wranken took that op- portunity of ascertaining different kinds of poisons. UNIVERSITY OF GOTTINGEN. This university proposes the following question as the subject of a prize essay, to be given in before July 1807:—~ «© What is the influence of the various taxations, on the morals and industry of the people ?”’ / SOCIETY OF SCIENCES, COPENHAGEN. Messrs. Chaptal and Cuvier have been elected members of this society. Professor Treschow, of Copenhagen, has been occupied during the winter in a course of lectures on anthropology, wherein he has severely criticised the speculations of Dr. Gall on the nature of the human soul. SOCIETY OF SCIENCES, GOERLITZ. Thie society has proposed the following subject of invesé tigation to the learned ; 1. Incloudy weather it freezes but in a small degree until the thermometer of Reaumur has fallen to the zero point, or at Jeast very little above it: Wherefore then, in a serene sky, does it freeze when the same thermometer is three or four degrees above the zero point? 2. Collect 188 Vuccination Kepler the Astronomer.—Astronomy. 2. Collect out of the works of Plautus every thing which relates to the knowledge of .men and manners of-his time, and arrange these) materials in such a manner as to produce a picture of civilization and manners at that epoch. * eT XXXII Intelligence haha taacdS anions Articles. NAGCIN ALTON. “bat Prussian government has given further éncourage- ment for the progtess of vaccination, by ordering medals to be struck of the value of fifty ducats in gold, and contain~ ing four ounces of silver each, to be given as prizes to those who contribute to its success.» - . ry KEPLER THE ASTRONOMER, A seinen has been opened at Ratisbon for a monu- ment to the memory of Kepler,the astronomer. It is to consist of a Doric temple 23 feet high, and is to be erected in the Sternbergian gardens. hee ASTRONOMY. . Table of the right Ascension and: Declination of Ceres, Pallas, and-Juno, for April 1806. Ceres. | Parnas. ; Juno. re R. Dee. N. AR. Dec. S.| AR. |Dec.N. 1806. {elm «| s h, m 3 |o° hi m s o 4 April 316 55 4/30 52/5 48 24/5 34 jill 2 20/7 12 616 58 28! 30 47/15 53 4414 48 L110 Sah se 97 2 8/30 40/5 59 124 4 1M 8 i Dwr: 4 8) hy All 6 Sl 12\7 +5 52/30 34/6 44 443 91 10 58 36,8 8 15|\7 9 48} 30 26116 10 dig 39 10 57 40| 8 24 18/7 13°52}30 1816 16 4/1 59 10 56 56/8 38 21)7°18. 0} 30 10/6 21 52\1 99, 10 56 28, 8 50 24\7 22 16/30 116 27 480 46 LOr 56) 12) 0.01 7 9717 26, 40) 29 51 6 33 440 12 “|10 56 419 10 30)7 31 12) 29 4116 39 48:0 20N./10 56 12) 9 17 ~ Ceres and Pallas are too near the sun to be any jong seen in this country. MECHANICS. Mechanics —Lesiures. 16g L MECHANICS. A mechanic of Copenhagen has made a'model of a praam intended to conduct; without danger, ships.of the largest di- mensions across the ice. His miodel/has been examined by the most celebrated engineers on the continent, and promises to be of great service to the Danish marine. __ LECTURES. i? Mr. Thelwall has opened a seminary for the cultivation of the science and practice:of elocution;:and the cure of impe- diments of speech ; and ‘has just commenced a course of lec- tures, at his house, No. 40, Bedford-place, Russel-square,. on the physiological principles of his art,“ and the causes, _ .ptévention; and:cure lof the several species» of unpediments, - natural and habitual... The; intention of the lecturer is to treat his subject-as a branch of natural) and experjmental philosophy ; to imyestigate the:laws of organic action wpon which the phenomenon of speech depend ; to consider at large the theory/of the human voice, and of human enuncia- tion; and.to apply the principles of that theory to the prac- tical improvement of the power and tone of the voice, and: the facilities of enunciative expression... For this purpose, besides. the more popular accoihpaniments of reading, reci- tations, and oratorical; digressions, the Jectures are illustrated by graphic and: mechanical demonstrations, of the essential propositions; and au attempt is made to place whatever re~ lates to the fundamental requisites, and even to many of the higher graces of elocutionary expression, on, the broad and sure foundations of anatomical and mathematical science. Even our perceptions of musical proportion, ahd the conse- quent laws of rousical composition, are referred, for their origin, to certain’ principles of physival necessity, resulting from the structure of the organs of voice :,and, from. the existing harmony between. these principles and our percep- tions of such proportions,; MrT. builds bis expectations of surmouhting all. impediments not resulting either from: deafness or imbecility of mind.> His plan, of course, in~ cludes the structure and application of artificial organs, &e., for the relief of those who haye absolute deficiencies or mal- vel conformations: 190 List of Patents for New Inventions. conformations of the mouth. The lecturer also proposes to receive into his house a limited number of pupils afflicted with impediments, and to give private instructions in all the various branches of elocution. LIST OF PATENTS FOR NEW INVENTIONS. A grant unto Patrick Whytock, of Liverpool, in the county palatine of Lancaster, merchant 5 for his invented improvements in the manufacture of piece goods, com- posed of cotton, of flax, or of ‘hemp, or of any mixture or mixtures of two or more of these articles, by which such goods will resist the rotting action of wet or moisture much better than similar fabrics manufactured by the methods in common use. Dated March 8. | To John Curr, of Sheffield-Park, in the parish of Sheffield, in the county of York, gentleman ; for his invented method, different from any that has hitherto been invented or known, of spinning hemp for the making of ropes or cordage. Dated as above. To Richard Willcox, of the parish of St. Mary Lambeth, in the county of Surrey, mechanist ; for his invented cer- tain machinery for glazing and graining leather, now usually performed by hand. Dated as above. To Edward Dampier, of Primrose-street, in the city of London, manufacturer; for his invented and brought to perfection certain machinery for rasping, grating, or re- ducing into small parts or powder, such woods, drugs, and other substances, for the use of dyers and others, as are not easily to be pulverized by mere percussion ; and also in re- gard that he is connected in trade with Edward Jackson and Thomas Shackleton, of Primrose-street aforesaid. Dated March 12. To Michael Logan, of Paradise-street, in the parish of Rotherhithe, in the county of Surrey, engineer for his invented and constructed entire new system of marine, fort, and field artillery. Dated March 13. To Charles Robert West, of Plough-court, Fetter-laney,in the city of London, optician, and William Bruce, of King’s- Head-court, Shoe-lane, in the city of London aforesaid, optical turner ; for their invented certain improvemepts in day List of Patents for New Inventions. 191 day or night telescopes, whereby the same will be rendered more portable than they now are. Dated March 18. To Henry Gore Clough, of Norton-street, in the parish of St. Mary-le-bone, and county of Middlesex, surgeon 5 for his inyented certain improvements in the instruments or apparatus commonly called trusses, which are used for compressing and supporting such parts of the human frame as are or may be ruptured or disposed to protrude. Dated March 21. To Francis Place, of Charing-cross, in the parish of St. Martin in the Fields, in the county of: Middlesex, tailor and mercer ; for his invented certain improvements in locks for muskets, pistols, fowling-pieces, carriage guns, and every species of fire-arms. Dated as above. To Richard Ottley, of Myrtle-hill, near Caermarthen, in Caermarthenshire, esq., and James Jeans, of Portsmouth, in the county of Hants, ship-builder; for their invented certain improvements in chain-pumps, in the mode of working the same, and in the wells for receiving such pumps, whereby much manual labour will be saved. Dated as above. To Joseph Hinchsliffe, of Dumfries, in that part of the united kingdom called Scotland ; for his invented new me- thod of manufacturing elastic spring trusses for ruptures or rupture bandages. Dated March 26. To Bracy Clark, of Giltspur-street, in the city of London, veterinary surgeon ; for his invented certain improvements upon horse-shoes. Dated as above. To Quintin M*‘ Adam, of Anderston, near the city of Glasgow, in the county of Lanark, in that part of the united kingdom of Great Britain and Ireland called Scotland ; for an improved method of dressing yarns for weaving, by means of a new and useful machine. Dated March 26. To William Parr, of Bermondsey New Road, in the county of Surrey, gentleman, Richard Bevington, of Gracechurch- street, in the city of London, merchant, and Samuel Be- vington, of Grange-road, Bermondsey, in the said county of Surrey, leather-dresser ; for their invented machine for splitting hides, skins, ‘pelts, or leather, in an improved manner. Dated as above. METEORO- ‘ 192 7 Days of » Mont Meteorology. METEOROLOGICAL TABLE, By Mr. Carey,’ or THe STRAND, © For Marck 1806. f “Thermometer. srubians pat cl the ig a Ew i * h. ; iS) 5 ey a atin. Feb. 26) 47°} 50°} 39° 27| 43 | 50 | 36 28| 34 | 43°| 34 nd} 35°} 42 | 35 ' gi 45 |. 50 | 46 3| 46 | 54 | 46 4| 37.| 44 | 34 5} 34 | 40 | 32 6| 32 | 37 | 32 7| 35 | 47 | 42 gs| 40 | 44 | 40 gi 42 | 43 | 32 10| 32 | 37 | 32 11] 32 | 36 | 28 12) 26 | 30°| 26 13} 25 | 36 | 33 14| 37 | 48 | 32 15} 32 | 42 | 33 16| 3 36 | 34 17} 36 | 37-1 35 18} 36 | 40 | 39 19] 39 | 46 | 40 20! 40 | 47°} 41 21) 40. | 52°| 46 29} 42 | 54-| 44 93, 46 | 57 | 49 24; 49 | 54 | 47 25} 47 | 52°| 47 26) 45 | 49 | 46 Height of the Karom. Inches, 1 | a | mm | 4 Giz bo lborny 2 sce g Weather. Asm 46° |Fair 42 |Fair, and wind ‘42 «=|Fair, and wind 15 |Cloudy 20° |Cloudy 15 |Showery 10 ‘|Fair 16 |Fair 92 «\Fair 26 |Cloudy 12 |Cloudy Oo. |Rain- 0 .|Snow 6 |Cloudy 0 (Snow 0 |Cloudy Oo |Rain 24 . |Fair oO. |Rain.. Oo {Rain o |Showery 10 |Cloudy 14 |Cloudy 30. {Fair . 15 .|Cloudy 24 {Cloudy 15 |Cloudy o {Rain 18 |Cloudy / { } | - WN,,B. The barometer’s height-is taken at noon. ree [ 193 } XXXIV. Account of a Series of Experiments, showing the Effecis of Compression in modifying the Action of Heat. By Sir James Haut, Bart. FLR.S. Edin. {Continued from p. 155.] Ill. Experiments made in Tubes of Porcelain.Tubes of Wedgewood’s Ware.—Methods used to confine the Car- bonic Acid, and to close the Pores of the Porcelain in a horizontal Apparatus.—Tubes made with a View to these Experiments.—The Vertical Apparatus adopied.—View of Results obtained both in Iron and Porcelain.—The Formation of Limestone and Marble.—Inquiry into the Cause of the partial Calcinations.—Tules of Porcelain weighed previous to breaking. — Experiments with Porce- lain Tubes proved to be limited. Wai I was carrying on the above-mentioned experi- ments, I was occasionally occupied with another set, in tubes of porcelain. So much, indeed, was T prepossessed. in favour of this last mode, that I laid gun-barrels aside, and adhered to it during more than a year. The methods followed with this substance differ widely from those already described, though founded on the same general principles. I procured from Mr. Wedgewood’s manufactory at Etru- ria, in Staffordshire, a set of tubes for this purpose, formed of the same substance with the white mortars, in common use, made there. These tubes were fourteen inches long, with a bore of half an inch diameter, and thickness of 0:2 3. being closed at one end (figs. 9, 10, 1), 12, 13*). I proposed to ram the carbonate of lime into the breech (fig. 9. A); then filling the tube to within a small distance of its muzzle with pounded flint (B), to fill that remainder (C) with common borax of the shops (borate of soda) pre- viously reduced to glass, and then pounded; to apply heat to the muzzle alone, sv as to convert that borax iuto solid glass; then, reversing the operation, to keep the muzzle * Plate IV., given in our last Number, Vol. 24. No. 95. Apriliso6. N cold, 194 Effects of Heat modified by Compression. cold, and apply the requisite heat to the carbonate lodged ir the breech. I thus expected to confine the carbonic acid; but the at- tempt was attended with considerable difficulty, and has led to the employment of various devices, which I shall now shortly enumerate, as they occurred in the course of prac~ tice. The simple application of the principle was found in- sufficient, from two causes: Ist, The carbonic acid being driven from the breech of the tube towards the muzzle, among the pores of the pounded silex, escaped from the compressing force, by lodging itself in cavities which were comparatively cold: 2dly, The glass of borax, on cooling, was always found to crack very much, so that its tightmess could not be depended on. To obviate both these inconveniences at once, it oceurred to me, in addition to the first arrangement, to place some borax (fig. 10. C) so near the breech of the tube as to un- dergo heat along with the carbonate (A); but interposing between this borax and the carbonate a stratum of silex (B), in order to prevent contamination. I trusted that the borax in a liquid or viscid state, being thrust outwards by the ex- pansion of the carbonic acid, would press against the silex bey ond it (D), and totaily prevent the elastic substances from escaping out of the tube, or even from wandering into its cold parts. In some respects this plan answered to expectation. The glass of borax, which can never be obtained when cold, without innumerable cracks, unites into one continued viseid mass in the lowest red heat; and as the stress in these ex- periments begins only with redness, the borax, being heated at the same time with the carbonate, becomes united and impervious as soon as its action is necessary. Many good results were accordingly obtained in this way. But I found, in practice, that as the heat rose, the borax began to enter into too thin fusion, and was often lost among the pores Of the silex, the space in which it +had lain being found empty on breaking the tube, It was therefore found neces- 7 8 oh. sary Effects of Heat modified by Compression. 105 sary to oppose something more substantial and compact, to the thin and penetrating quality of pure borax. In searching for some such substance, a curious property of bottle-glass occurred accidentally. Some of this glass, in powder, having been introduced into a mufile at the tem- perature of about 20° of Wedgewood ; the powder, in the space of about a minute, entered into a state of viscid agglu- tination, like that of honey, and in about a minute more {the heat always continuing unchanged) consolidated into a firm and compact mass of Reaumur’s porcelain*. It now appeared, that by placing this substance immediately behind the borax, the penetrating quality of this last might be ef- fectually restrained ; for Reaumur’s porcelain has the double advantage of being refractory, and of not cracking by change of temperature. I found, however, that in the act of con- solidation, the pounded bottle-glass shrunk, so as to Jeave an opening between its mass and the tube, through which the borax,’ and along with it the carbonic acid, was found to escape. But the object in view was obtained by means of a mixture of pounded bottle-glass and pounded flint, in equal parts. This compound still agglutinates, not indeed into a mass so hard as Reaumur’s porcelain, but sufficiently so for the purpose; and this being done without any sen- sible contraction, an effectual barrier was opposed to the borax; (this arrangement is shown in fig. 1}.;) and thus the method of closing the tubes was rendered so complete, as seldom to fail in practicef. A still further refinement upon this method was found to be of advantage. A second series of powders, like that already described, was introduced towards the muzzle, as shown in fig. 12. During the first period of the experiment, this Jast-mentioned series was ex- posed to heat, with all the outward half of the tube (al); * In the same temperature a mass of the glass of equal bulk would undergo the same change; but it would occupy an hour. + A substance equally efficacious in restraining the penetrating quality of borax, was discovered by another accident. It consists of a mixture of borax and common sand, by which a substance is formed, which, in heat, assumes the state of a very tough paste, and becomes hard and compact on cooling. N@ by 196 Effects of Heat modified by Compression. by this means a solid=mass was produced, which remained cold and firm during the subsequent action of heat upon the carbonate. I soon found that, DE cukinnties all the above-men- tioned precautions, the carbonic acid made its escape, and that it pervaded the substance of the Wedgewood tubes, where no flaw could be traced. It occurred to me, that this _ defect might be remedied, were borax, in its thin and pene- trating state of fusion, applied to the inside of the tube; and that the pores of the porcelain might thus be closed, as those of leather are closed by oi] in an air-pump. In this view T rammed the carbonate into a small tube, and surrounded it with pounded glass of borax, which, as soon as the heat was applied, spread on the inside of the large tube, and ef- fectually Hath its pores. In this manner, many good ex- periments were made with barrels lying horizontally in com- mon muffles (the arrangement just described being repre- sented in fig. 13). I was thus enabled to carry on experiments with this porcelain, to the utmost that its strength would bear. But I was not satisfied with the force so exerted; and, hoping to obtain tubes of a superior quality, I spent much time in experiments with various porcelain compositions. In this I so far succeeded as to produce tubes, by which the car- bonic acid was, in a great measure, retained without any in- ternal glaze. The best material I found for this purpose was the pure porcelain clay of Cornwall, or a composition in the proportion of two of this clay to one of what the potters call Cornish stone, which I believe to be a granite ina state of decomposition. These tubes were seven or eight inches long, with a bore tapering from 1 inch to0°6 Their thick- ness was about 0°3 at the breech, and tapered towards the muzzle to the thinness of a wafer. I now adopted a new mode of operation, placing the tube vertically, and not horizontally as before. By observing the thin state of borax whilst in fusion, J was convinced that it ought to be treated as a complete liquid, which being supporte: din the course of the experiment from below, weutd secure Effects of Heat modified by Compression. 197 secure perfect tightness, and obviate the failure which often happened in the horizontal position, from the falling of the borax to the lower side. f In this view (Plate VII. fig. 16.), I filled the breech in the manner described above, and introduced into the muzzle some borax (C) supported at the middle of the tube by a quantity of silex mixed with bottle-glass (B). I placed the tube so prepared, with its breech plunged into a crucible filled with sand (E), and its muzzle pointing upwards. It was now my object to apply heat to the the muzzle half, whilst the other remained cold.’ In that view, 1 constructed a furnace (fig. 14. and 15.), having.a mufile placed vertically (cd), surrounded on all sides with fire (e¢), and open both above (at c), and below (at d). The crucible just mentioned, with its tube, being then placed on a support directly below the vertical muffle (as represented in fig. 14. at J’), it was raised so that the half of the tube next the muzzle was introduced into the fire. In consequence of this, the borax was seen from above to melt, and run down in the tube, the air con- tained in the powder escaping in the form of bubbles, tll at last the borax stood with a clear and steady surface dike that of water. Some of this salt, being thrown in from above, by means of a tube of glass, the liquid surface was raised nearly to the muzzle, and, after all had been allowed to become cold, the-position of the tube was reversed; the muzzle being now plunged into the sand (as in fig. 17.), and the breech introduced into the muffle. In several ex- periments I found it answer well, to occupy great part of the space next the muzzle with a rod of sand and clay pre- viously baked (fig. 19. KK), which was either introduced at first, along with the pounded borax, or, being made red hot, was plunged into it when in a liquid state. dn many cases I assisted the compactness of the tube by means of an internal glaze of borax; the carbonate being placed in 2 small tube (as shown in fig. 18). These devices answered the end proposed. Three-fourths of the tube next the muzzle was found completely filled with a mass, having a concave termination at both ends, (fand ¢, figs. 17, 18, 19,) showing that it had siood as a liquid " N3 in 198 Effects of Heat modified by Compression. in the two opposite positions in which heat had been applied to it. So great a degree of tightness, indeed, was obtained in this way, that I found myself subjected to an unforeseen source of failure. A number of the tubes failed, not by explosion, but by the formation of a minute longitudinal fissure at the breech, through which the borax and carbonic acid escaped. I saw that this arose from the expansion of the borax when in a liquid state, as happened with the fusi- ble metal inthe experiments with iron barrels ; for the cre- vice here formed indicated the exertion of some force acting very powerfully, and to a very small distance. Accordingly, this source of failure was remedied by the introduction of a very small air tube. This, however, was used only ina few experiments. In the course of the years 1801,.1802, and 1803, I made a number of experiments, by the various methods above de~ scribed, amounting, together with those made in gun-bar- rels, to one hundred and fifty-six. In an operation so new, and in which the apparatus was strained to the utmost of its power, constant success could not be expected; and, in fact, many experiments failed, wholly or partially. The re- sults, however, upon the whole, were satisfactory, since they seemed to establish some of the essential points of this inquiry. These experiments prove, that, by mechanical constraint, the carbonate of lime can be made to undergo strong heat without calcination, and to retain almost the whole of its carbonic acid, which, in an open fire, at the same tempe- rature, would have becn entirely driven off; and that, in these circumstances, heat produces some of the identical effects ascribed to it in the Huttonian theory. By this joint action of heat and pressure, the carbonate of lime, which had been introduced in the state of the finest powder, is agglutinated into a firm mass, possessing a degree of hardness, compactness, ana specific gravity *, nearly ap- proaching to these qualities in a sound limestone; and some of the results, by their saline fracture, by their semi-trans- * See Appendix—(to be given in a future Number.) parency, Se ee Se Effects of Heat modified by Compression. 199 parency, and their susceptibility of polish, deserve the name of marble. a The same trials have been made with all calcareous sub- stances ; with chalk, common limestone, marble, spar, and the shells of fish. All have shown the same general pro- perty, with some varieties as to temperature. Thus | found, that, in the same circumstances, chalk was more susceptible of agglutination than spar; the latter requiring a heat two degrees higher than the former, to bring it to the same pitch - of agolutination. The chalk used in my first experiments always assumed the character of a yellow marble, owing probably to some slight contamination of iron. When a solid piece of chalk, whose bulk had been previously measured in the gage of Wedgewood’s pyrometer, was submitted to heat under com> pression, its contraction was remarkable, proving the ape proach of the particles during their consolidation; on these occasions, it was found to shrink three times more than the pyrometer-pieces in the same temperature. It lost, too, al- most entirely, its power of imbibing water, and acquired a great additional specific gravity. Ou several occasions I ob- served, that masses of chalk, which, before the experiment, had shown one uniform character of whiteness, assumed a stratified appearance, indicated by a series of parallel layers of a brown colour. This circumstance may hereafter throw light on the geological history of this extraordinary sub- stance. I have said, that, by mechanical constraint, almost the whole of the carbonic acid was retained: And, in truth, at this period some loss of weight had been experienced in all the experiments, both with iron and porcelain. But even this circumstance is valuable, by exhibiting the influence of the carbonic acid, as varied by its quantity. When the loss exceeded 10 or 15 per cent.* of the weight of the carbonate, the result was always of a friable texture, * I have found that, in open fire, the entire loss sustained by the carbonate varies in different kinds from 42 to 45-5 per cent, N4 and 900 Effects of Heat modified by Compression. and without any stony character; when less than 2 or 3 per cent., it was considered as good, and possessed the proper- ties of a natural carbonate. In the intermediate cases, when the loss amounted, for instance, to 6 or 8 per cent., the result was sometimes excellent at first, the substance bear- ing every appearance of soundness, and often possessing a high character of crystallization ; but it was unable to resist the action of the air; and, by attracting carbonic acid or moisture, or both, crumbled to dust more or less rapidly, according to circumstances. This seems to prove, that the carbonate of lime, though not fully saturated with carbonic acid, may possess the properties of limestone ; and perhaps a difference of this kind may exist among natural carbonates, and give rise to their different degrees of durability. I have observed, in many cases, that the calcination has reached only to a certain depth into the mass; the internal part remaining in a state of complete carbonate, and, in ge- neral, of a very fine quality. The partial calcination seems thus to take place in two different modes. By one, a small proportion of carbonic acid is taken from each particle of carbonate; by the other, a portion of the carbonate is quite calcined, while the rest is left entire. Perhaps one result is the effect of a feeble calcining cause, acting during a long time, and the other of a strong cause, acting for a short time. Some of the results which seemed the most perfect when first produced, have been subject to decay, owing to partial calcination. It happened, in some degree, to the beautiful specimen produced onthe 3d of March 1801, re a fresh fracture has restored it. A specimen, too, of marble, formed from pounded spar, on 15th May 1801, was so complete as to deceive the work- man employed to polish it, who declared, that, were the substance a little whiter, the quarry from which it was taken would be of great value, if it lay within reach of a market. Yet, in a few weeks after its formation, it fell to dust, Numberless specimens, however, have been obtained which resist the air, and retain their polish as well as any marble. . Some Effects of Heat modified by Compression. 201 Some of them continue ina perfect state, though they have been kept, without any precaution, during four or five years. That set, in particular, remain perfectly entire, which were- shown last year in this society, though some of them were ‘made in 1799, some in 1801 and 1802, and though the first eleven were long soaked in water, in the trials made of their specific gravity. A curious circumstance occurred in one of these experi- ments, which may hereafter lead to important consequences. Some rust of iron had accidentally found its way into the tube: ten grains of carbonate were used, and a heat of 28° was applied. The tube had no flaw; but there was a cer- tainty that the carbonic acid ‘had escaped through its pores. When broken, the place of the carbonate was*found occu* pied, partly by a black slaggy matter, and partly by spheri- cles of various sizes, from that of a small pea downwards, of a white substance, which proved to be quicklime; the sphericles being interspersed through the slag, as spar and agates appear in whinstone. The slag had certainly been produced by a mixture of the iron with the substance of the tube; and the spherical form of the quicklime seems to show that the carbonate had been in fusion along with the slag, and that they had separated on the escape of the car- honic acid. ‘ : The subject was carried thus far in 1803, when I should probably have published my experiments, had I not been induced to prosecute the inquiry by certain indications, and accidental results, of a nature too irregular and uncertain to meet the public eye, but which convinced me that it was possible to establish, by experiment, the truth of all that was hypothetically assumed in the Huttonian theory. The principal object was now to accomplish the entire fusion of the carbonate, and to obtain spar as the result of that fusion, in imitation of what we conceive to have taken place in nature. f It was likewise important to acquire the power of retain~ ing all the carbonic acid of the carbonate, both on account of the fact itself, and on account of its consequences; the result 202 Effects of Heat modified by Compression, result being visibly improved by every approach towards complete saturation. I therefore became anxious to inves- tigate the cause of the partial calcinations which had always taken place, to a greater or a less degree, in all these experi- ments. The question naturally suggests itself,—What has become of the carbonic acid separated in these partial cal- cinations from the earthy basis? Has it penetrated the ves- sel, and escaped entirely ; or has it been retained within it ip a gaseous, but highly compressed state? It occurred to me, that this question might be easily resolved, by weighing the vessel before and after the action of heat upon the car~ bonate. With iron, a constant and inappreciable source of irregu- larity existedgin the oxidation of the barrel. But with porce- lain the thing was easy; and I put it in practice in all my experiments with this material, which were made after the question had occurred to me, The tube was weighed as soon as its muzzle was closed, and again after the breech had been exposed to the fire; taking care, in both cases, to allow all to cool. In every case I found some loss of weight, proving that, even in the best experiments, the tubes were pene- trated to a certain degree. I next wished to try if any of the carbonic acid separated, remained within the tube in a gaseous form ; and in that view, I wrapped the tube, which had just been weighed, in a sheet of paper, and placed it, so surrounded, on the scale of the balance. As soon as its weight was ascertained, I broke the tube by a smart blow, and then replaced upon the seale the paper containing all the fragments. In those experiments, in which entire calcina- tion had taken place, the weight was found not to be changed, for all the carbonic acid had already escaped during the action of heat. But in the good results I always found that a Joss of weight was the consequence of breaking the tube. These facts prove, that hoth causes of calcination had operated in the porcelain tubes; that, in the cases of small Joss, part of the carbonic acid had escaped through the ves- sel, and that part had been retained within it. J had in view A new Fact in Galvanism. 203 yiew methods by which the last could be counteracted; but I saw no remedy for the first. 1 hegan, therefore, to de~ spair of ult:mate success with tubes of porcelain *. Another circumstance confirmed me in this opinion. [T found it impracticable to apply a heat above 27° to these tubes, when charged as above with carbonate, without de- stroying them, either by explosion, by the formation of a minute rent, or by the actual swelling of the tube. Some times this swelling took place to the amount of doubling the interna] diameter, and yet the porcelain held tight, the carbonate sustaining but a very small loss. This ductility of the porcelain in a low heat is a curious fact, and shows what a range of temperature is embraced by the gradual transition of some substances fram a solid to a liquid state ; for the same porcelain which is thus susceptible of being stretched out, without breaking, in a heat of 27°, stands the heat of 152°, without injury, when exposed to no violence, the angles of its fracture remaining sharp and entire. [To be continued. ] KXKV. 4 new Fact in Galvanism. Commynicated by a@ Correspondent. To Mr. Tilloch. SIR, Wisurxe to promote Galvanic inquiries (when unattended with cruelty), 1 shall beg the favour of you to insert in your Magazine the following circumstances, which I do not know have been observed before : In trying to produce the nervous flashings by resting dif- ferent parts of the face on a cylinder of wood covered with tin-foil, 1 was surprised by perceiving, when the nose was on this cylinder, that there was a strong disagreeable sinell, like that which is produced in making inflammable air (hy- * I am nevertheless of opinion, that, in some situations, experiments with compression may be carried on with great ease and advantage in such tubes, J allude to the situation of the geclogists of France and Germany, who may easily procure, from their own manufactories, tubes of a quality far superior to any thing made for sale in this country. drogen 204 On Vaccination. drogen gas) in the common way, with sulphuric acid, water, and iron filings. This result I experienced several times ; the cylinder resting on the copper end of a Galvanic, trough consisting of 25 pairs of plates, 2} inch. When the nose was placed on a cylinder connected with the zine end, no such smell was produced. Quere, How was the inflam- inable air (if any was) produced to make so strong a smell? The first time I perceived this smell was on Saturday last. I again tricd the experiment this evening, and found the same result. I likewise tried it with two troughs, consisting. in all of 50 pairs of plates; and then also perceived the smell; but the experiment was from the number of plates so very unpleasant (the shock being great) that I did not continue it very long, and did not determine whether the smell was proportionally strong. With these 50 pairs of plates another effect occurred, which J had never seen before. I introduced in the circuit a small glass tube filled with milk instead of water, and whilst it remained in its place I did not see any alteration take place ; but when I took out the wire, which was a silver one, and had been connected with the zinc end, I found a sort of crust adhering to it which looked like cream. Quere, Was not this curd formed by acid from the zine end? A gold wire, which was connected with the copper end, I neglected to examine. April 7, 1806. A Friend to Physical Inquiries. XXXVI. On Vaccination. An Examination of several of the Mis-statements of Dr. Rowizy. By Mr. J. J, Waw- Kins, of Islington. ain; To Mr. Tillock. AvinG for some years seen the most beneficial effects from the introduction of the cow-pock, as well from the practice of many of my friends, as with several I have my- self vaccinated, I felt it a duty, on the first publication of Dr. Rowley’s pamphlet, entitled ‘* Cow-Pox Inoculation ng Security On Vaccination. 205 Security against Small-Pox Infection,” to examine some of his alleged cases, in order that I might judge for myself, whether I ought to continue favourable, or become adverse to the new inoculation. It was at first my intention to examine the whole of his cases ; but, hearing that the indefatigable Dr. Thornton had undertaken the task, and knowing he was better qualified than myself, I relinquished it, site visiting ten of the 218 eases detailed in Dr. Row ley’s oalied tion! Of these ten, there were three grossly misrepresented ; four could not be proved to have gone regularly through the cow-pock ; of one no information could be had, the father of the child having died a twelvemonth before Dr. Rowley published the ; case; and two were most pointedly in favour of vaccination. * Dr. Rowley’s scandalous pamphlet would have been to- tally unworthy of the least notice had he not addressed him- self to the passions, and thereby wrought upon the credulity of the ignorant and unthinking ; which renders it necessary that the cause of truth and humanity should be vindicated. I understand there are several replies to Dr. Rowley, two only of which have come into my hands; one, a most ex- cellent satirical piece, by ‘* Aculeus;” the other by Dr. Thornton, two reports only of whose labours are as yet pub- lished: so far as he has already gone, he has entirely dis- proved and overturned Dr. Rowley’s statements, and ex- posed the baseness of antivaccinarian proceedings. From my own cbservations and practice, I can truly say, I have met with nothing but the most satisfactory evidence in favour of vaccine inoculation, and therefore I conceive it my duty to promote it by all the means in my power. Al- though the subject is so well handled by the two authors just mentioned, I think it will be of use to contribute my mite to the general stock of evidence, and shall be glad you will insert in your valuable Magazine the following state- ment of my examination of the ten cases: Case 1. The case of Marianne Lewis, which is the §8th in Dr. Rowley’s list, and the subject of one of his en- gravings, I examined with very particular attention. _ The doctor states, that she was vaccinated.‘ at the Small- Pox 606 On Vaccination. Pox Hospital April 1803, and that in June 1804 she broke out in the head, ears, and chest, with cow-pox mange, cow-pox blueish abscesses: when the cold weather came, they were better. In May 1805, the same cow-pox mange, cow-pox abscesses, blueish in appearance, attacked the child in every part of the body, fron the head to the foot; there were nothing but cow-pox mange, cow-pox gatherings of matter, cow-pox ulcers, excoriations: the child was a mere Lazarus, covered all over with sores and disease 3 a most disgusting spectacle of terrible disease.” On my visiting this child in October 1805, the mother told me that it was vaccinated in May 1803. There were about 200 vaccinated at the same time. She never carried her to be seen afterwards. There was no regular pustules Lut only a little sore without inflammation, which soon healed wp. The child was particularly healthy till April 1804, when she had eruptions on the head and breast, which continued four months. She was then guete well, ull May last, when the eruptions came again, and extended all over the body: they are now, for the most part, healed. She says also, that Dr. Rowley gave it as his opinion, that the sore was neither cow-pock nor small-pox, but something between both. From both these statements it appears that the child was inoculated for the cow-pock, and afterwards had an erup- tion; but the doctor has carefully omitted that, which would have made it no evidence in his favour, namely, that the child did not take the cow-pock, although inoculated for it, and that, for eleven months after the inoculation, she was particularly healthy. There is some difference also in the time of the eruption: the doctor states it to commence in June, and to become betier in cold weather ; but the mother says it commenced in April, and continued four months, (2/1 August, the hot- test month in the year,) when the child was quite well, tll the May follow’ ing. From my own examination I am induced to believe that the eruption was very far from being all over the body; but it was sufficient for the doctor’s purpose, if he could any way twist facts to favour the antivaccine principles, for —— On Vaccination. 07 for which end he has most grossly misrepresented this case. Case 2. Mr. Joules’s son, Dr. Rowley’s 36th case, stated as follows :—** Vaccinated at the Small-Pox Hospital; ter- rible tumour in the face, of which a drawing is given re- sembling an ox.” I saw this child, with his parents, in November 1805. The father told me that the boy was vaccinated four or five years since: soon afterwards he had a slight breaking out on the face, which continued about a month: from that time he was perfectly well for three or four years, when a swelling came in his cheek, but was attended with so little pain, that it did not hinder his playing in the streets as much as other boys. Mr. Joules said. Dr. Rowley pro- mised to undertake the cure gratis, but never troubled him- self about it after he had the boy’s picture. The father and mother loth declared they did not think the swelling was caused by the cow-pock. It appeared to me a scrophulous ease, and nothing could be further fetched than the notion of its resembling an ox. Case 3. Mr. Wild’s child, the doctor’s 135th case, who, he says, took the small-pox, in the natural way, in Au- gust 1805, although vaccinated two years before. I saw the mother and child in October 1805. She said the child was vaccinated three or four years lefore it took the small-pox ; but the place of inoculation was very small, and did not appear like the cow-pock she had seen in other persons ; from whence it is evident, although the child was moculated for the cow-pock, it did not receive it. Is it any wonder then, that the small-pox infection took place when the child was exposed to it? Certainly not. And it is there= fore a gross misrepresentation of the case, to call it an in- stance of cow-pock failure. 4 Case 4, Mr. Colson’s grandson, Dr. Rowley’s 137th case. This he states took the small-pox’ two years after €ow-pox. : In October 1805, I saw Mr. Colson, the grandfather, and also the child’s mother, who was but seventeen years of age when Wr child was vaccinated; and thoughtlessly nedleétet to £68 On Vaccination. to carry it to the Skinner-street station, where it was inoctt= Jated, to be examined so often as required by the rules of the institution. This, she told me, was entered in the books at the station. It therefore cannot be known that the child went regularly through the cow-pock. Cases 5 and 6. Mrs. Little’s two children, Dr. Rowley’s 77th case. He states the small-pox bappening three years after vaccination: but from every information I could ob- tain from the mother and others, there is no proof that they passed regularly through the cow-pock, and consequently they ought not to have been brought forward as cases against vaccination. Case 7. Mr. Nicholson’s boy, the doctor’s 35th case: *€ Small-pox two years after vaccination.” The regularity of the vaccination is not proved; and there is no other evi- dence of the child’s having the small-pox, than Dr. Rowley’s saying there was one small-pock on its posteriors, from which he could have taken matter ! Case 8. Mr. Rice’s child, case 197 of Dr. Rowley. I could obrain no other information, than that Mr. Rice had been dead above a year, and the family removed, but could not learn where. Cases 9 and 10. Elizabeth and William Keen, Dr. Row- Jey’s 37th and 38th cases; both of which he states thus: ** Vaccinated May 10th, 1805; small-pox 29th of May.” I saw these two children, with,their mother, in Novem- ber 1805. Her relation was as follows:—She has three children, one of whom took the small-pox in the natural way, and had them very severely ; and there was no doubt of the other two having caught the infection ; but, by the advice of some friends, she had them vaccinated, hoping thereby to lessen the virulence of the small-pox. The result justified the procedure: the two vaccinated children passed through the small-pox so favourably, that their healths were scarcely impaired, and it was not easy to determine which of the two diseases predominated in the constitution ; whereas . the one that was not vaccinated, languished under a most distressing confluent small-pox, which left numerous inde- lible marks all over the face; besides a large and disgusting scar Method of extracting Spirits from Potatoes. 209 Scar on the neck, just above the right clavicula; together with a general debility, which six months of time had hardly lessened. Thus is seen, that these two cases, which Dr. Rowley has, by misrepresentation, endeavoured to warp to his own purposes, are most pointedly and strongly favourable to vac- cination: how far it is so with the rest on his black list, will no doubt appear soon, from the labours of Dr. Thorn- ton. I have much reason to believe they will, for the most part, be proved to be misrepresentations of facts, in them- selves neither for nor against vaccination: some few mis- takes may have arisen from the inexperience of the early vac- cinators,—this was to be expected by every rational person : many of the cases will be found highly favourable to vac- cination ; but a considerable number of them contain their own refutation, which any one who reads with attention may discover. I am, sir, Your humble servant, Islington, Joun J. HAWKINS. March 24, 1806. XXXVII. On the Method of extracting Spirits from Po- tatoes. By M.Gerrmatn, Chemist to the Military Hos- pital at Hanau*. 1, has been the practice, for a long time past, in Germany to distil spirits from potatoes. In the eastern part of Prussia, and in Lithuania, they employ an immense quantity of these vegetables in distillation, In these countries they are gene- rally planted as the first crop in grounds which had been for- “merly untilled; and with proper care, and in good seasons, they produce abundantly. The residue, after distillation, is an excellent drink for cattle, particularly cows, whose milk is greatly increased by the use of it. When potatoe spi- rit is properly distilled, if not mixed with any foreign mat- ter, and if the potatoes have not been heated too much, or burnt, during their preparation, it has a taste and * From Annaies de Chimie, tome lvi. p. 207. Vol. 24. No. 95. April 1806. O flayour y ‘ 210 | Method of extracting Spirits from Potatoes. flavour far superior to the spirit produced from barley, or eats, which is preferred only from custom. It has been said that potatoe spirit sours easily, and is spoiled upon crossing the line: as [ have not had an oppor- tunity of proving the contrary, I have nothing to say at pre- sent to these two objections; I know, however, for certain, that it has been preserved in good condition for eighteen months, and that, according to the areometer of, Richter *, regulated for the experiment, it marked the 35th degree, without having lost any of its good qualities, or being soured. From the result of this experiment I have every reason to believe that this spirit, if well prepared, is no more subject to the two inconveniences with which it is re- proached, than that produced from grain, and that every thing which has been said against it has arisen from pre- judice. Method of performing the Operation of producing Potatoe Spirit. A sufficient quantity of malt must be added to the pota- toes; for instance, 100 bushels of potatoes require 17 bushels: and a half of malt; and this quantity will producefive hogs- heads of spirits, which, according to the areometer of Rich- ter, marks from the 36th to the 38th degree. I know also, by experience, that out of 120 bushels of potatoes, and 10 of malt, we obtain the same quantity of spirit, and of the same strength. It may be thought, per- haps, that to produce the same quantity of spirits from po- tatoes, it requires a larger proportion of fermenting materials: than common grain does, as well as more room, a greater number of casks, and a greater expense of firing: but all this is a mistake; because the same casks which contain a determinate quantity of grain will contain an equal quantity of potatoes and malt. These will also produce the same * Richter’s areometer is the same as that of Baumé, with this exception, that each degree of the former instrument is constructed after experiments expressly made for the purpose. ‘The scale is graduated into 100 parts, in such a manner that the number at the Jevel of the liguid denotes the quan- tity of alcohol. Thus, 36, indicates 36 parts of alcoholin 100 parts of the liquid. es 3 quantity Method of extracting Spirits from Potatoes. 911 quantity of spirits, provided care is takén not to dilute the potatoes so much as grain, because they have not the Same property of swelling which grain has; and provided also, that a good fermentation has been produced, and the spirits have not been burned in the still. As for the fewel required to prepare the potatoes, the additional expense is trifling, although, in every case, boiling water is made use of. Water in this state is used to prepare the potatoes, as the operation is performed by means of the steam of the water, which it is necessary to keep boiling half an hour or three quarters longer, according to the quantity of potatoes employed; and this is the only additional expense which may be reckoned upon, The preparation of the potatoes must be carried on in ves- sels made of oak, the staves of which ought to be very thick and solid, and the bottom bound round with iron, in order to guard against accidents in removing. The top of the vessel must have a square aperture, with a thick coycring, which should fit exactly; this aperture serves to let the po- tatoes into the vessel after being well washed: there ought to be another smaller aperture in the side, with a covering to shut close, for the purpose of drawing the potatoes out of the vessel. It is then placed upon a tressel by the side of a still, dif- ferent from that which is used for general purposes. On the same side, 7. e. opposite to the still, and a little above the lower part of the tun, there is an aperture into which the beak of the still is inverted, by means of which the steam is conveyed to the potatoes. In the centre of the bot- tom of the tun there should be another small aperture, through which to evacuate any thick fluids which may collect in the tun; and in order that the weight of the potatoes may not choke it, the cover should be made to open inwards. When the potatoes are prepared, which the workmen will easily discover by means of the apertures in the tun already de- scribed, the beak of the alembic is withdrawn; the potatoes are immediately afterwards ground by a machine, or a kind of handmill, placed before the tun close to the small side- aperture Fhis mill is composed of two cylinders of very O02 hard at2 Method of extracting Spirits from Potatoesy hard wood, or stone, which may be drawn more or less to~ gether, as occasion requires, by means of a wheel and a handle to if, which serves to drive the axles of the cylinders together. Above the cylinders there is a trough or hopper, into which the potatoes are, put after being drawn out of the tun, by little and little, by means of a shovel ; and being bruised by the action of the cylinders in this trough, they fall imme- diately into a tub placed below them. What renders this tub indispensable, is, that below each cylinder there is an iron scraper, to detacly the boiled potatoes which may ad- here to the cylinders. When the potatoes are thus prepared, the grated barley is put into a tub and diluted with lukewarm water, taking care not to dilute it too much: the potatoes are then mixed with it by tubfulls as they are ground, and when they are finished the necessary quantity of water is added, and both ingredients are stirred until perfectly well mixed, and not the least lump left. The liquor is then left to settle ; stirring it, however, at intervals until the whole is cold, and in a proper state to receive the yeast. In some places beer yeast is used ;. but in others an arti- ficial ferment is prepared, composed simply of clean ground rice. This last yeast is prepared by kneading the ground rice in cold water; boiling water is then added until a thick broth is formed. All the efficacy of this preparation results from the care taken in heating it: if too much or too little heated, the whole mass wilt be spoiled. To conclude :—It may be observed that potatoes ferment much more easily than grain, and require less yeast ; the fer- mentation besides is very strong, and: produces a great quan- tity of froth; but it does not operate alike through the whole of it, because, in particular places, the gross and membranous part of the potatoes forms a strong crust above, through which the froth cannot penetrate so easily. Expe- rience shows that, upon distilling potatoe spirits with car- rots and beet-root, the spirit then drawn is better and more abundant than when made with potatoes and beet-root alone; and the advantages reported to have been derived from . Means of destroying Insects and Caterpillars. 23 from this last method of proceeding have not been con- firmed: on the contrary, it is completely proved, that the addition of carrots gives the spirits an exquisite taste and flavour. Chemists pretend that it is the saccharine substance which causes the vinous fermentation ; that the more of this sub- stance any body contains, the better adapted it is for fer- mentation. The present experiments on potatoes seem to prove that this assertion is not strictly correct ; for they con- tain no saccharine substance, but merely starch, and yet they ferment. We see in corn, that the quantity of spirits is in proportion to that of the starch, or perhaps the glutinous substance which it contains: wheat, for instance, which contains both the one and the other, in greatest abundance, yields also the greatest quantity of spirits. The opinion of those who assert that corn in germinating acquires thereby a mildness, seems to me of no weight, be- cause hitherto little light has been thrown on the subject 5 which has not been yet exhausted by rigorous experiments comparing the different kinds of grain, germinated and not germinated. There are some very intelligent distillers, whe still doubt if a determinate quantity of grain produces a greater quantity of spirits because that grain has germi-~ nated. XXXVIII. Means of destroying the Inseets and Caterpillars which attack Fruit Trees. By Mapan Gacon Dourour* W: know, by sad experience, that the husbandman has every year some accidents which unexpectedly diminish or destroy the produce of his ground, without having to re- proach himself with any want of care or attention. The present year, for instance (1805), offers a singularity which I bave not before perceived. In some districts the cherry-tree has experienced, at the time of its blossoming, * From Bibliothique Physigue Economique, No. 12, August 1805. 03 colds 214 Means of destroying Insects and Caterpillars. colds and winds which have prevented it from setting; but another plague, not less disastrous, has attacked the cherry~ trees and plum-trees over several districts in France. Great swarms of little animals resembling vine-fretters, but which are not so in reality, established their habitations at the extremity of the branches of the cherry-trees. As soon as a branch was attacked, the leaves curled, and the juice was dried up. On opening the leaf a considerable number of ants was discovered, which, jointly with the insect which began the ravages, sucked the branch, and made it wither, What I have remarked is, that usually, when the vine-fret- ters attack any tree, the neighbouring tree very soon expe- riences the same fate; but the attack of this year is only partial. In an alley of cherry-trees which I possess there have seven been attacked, but not those which are next each other. One tree was placed between two which were very much damaged by these insects, and yet this one was not hurt. On these vermin the smoke of tabacco had no effect at all: this convinces me that they are different from the ordi- nary kind. Plum-trees, when attacked by the same insect, do not lose their fruit like the cherry-trees; but the little animals cover them with more rapidity, so as to extirpate even the appear ance of fruit. Having effectually watered a low plum-tree, I covered it with ashes, in the manner we treat beans and cabbages, and the vermin were destroyed: but this is only practicable with a tree of low height. I made one remark, which I think 1s essential to commu- nicate: it is, that plum-trees planted in ground which is not necessarily watered, are less attacked by these insects than those which have experienced a humidity communicated by the plants in their neighbourhood, to which watering is ab-. solutely necessary. I had one planted in a bed of arti- chokes: we know very well that this plant requires plenty of water; and the tree was entirely covered with insects. Its leaves siiincads and the fruit fell off; while two other plum- trees, On the Gaseous Oxide of Azote. 215 trees, in ground not watered at all, were much less attaeked. This convinces me that these were not the ordinary vermin abundant in dry seasons. I was only able to protect my cherries a little, by cutting off the extremities of the damaged branches. Several people had recourse to sulphur; but I did not fol- Jow that method. The smoke of sulphur destroys the insect, I admit, but it is at least equally dangerous to the tree; I always prefer an aspersion of the tree with soap-suds. This very year I experienced the good effects of it. I saw my plum-trees look green‘again, and the insects abandon them. The aspersion is very easily managed, by means of watering- pots or small garden-engines. I have also employed a ley of wood-ashes with the same success as soap and water. An observation equally important which I have made is, the great damage done this season in all orchards by the caterpillar. As soon as they devoured the young leaves they attacked the fruit. In spite of the great care taken in spring to get rid of them, the number of these insects is in- credible. I have seen them unite on the large branches, fix their nests to them, and protect them by means of the downy matter which covers the buds of the ensuing season. Whatever precaution is taken, it is almost impossible not to destroy these buds. It is only necessary to take off these nests and burn them; and this is the only way of getting rid of the coveys. I employed the same aspersion for my apple-trees, and by that means got rid of their enemies also. KXXIX. Experiments upon the Gaseous Oxide of Axote, made at a Meeting of Amateurs, of Toulouse. Described by M. Dispan, Professor of Chemistry in the Institution: of thai City * For several years past, plenty of experiments have been published on the effects of the gaseous oxide of azote in- haled into the lungs. But these experiments, almost always ® From Annales de Chimie, tome lvi, 04 different, 216 On the Gaseous Oxide of Axote. different, and often contradictory, in their results, present no basis positive enough on which to ground an opinion on the subject. Such, at least, were the motives which induced several distinguished chemical amateurs of Toulouse to judge of the singular properties attributed to this species of gas, by actual'experiments made on themselves. As I can answer for the purity of the substances employed, and the general precautions used on the occasion; and having also taken minutes on the spot of the effects of the gas on twelve per- sons at least, several of whom repeated it two or three times 5 I presume that this publication will be read with some in- terest. First Meeting. The nitrate of ammonia made use of was confusedly cry- stallized, but nevéltlieless very neutral. The taste was pun- gent, and it had a slight smell. It had been wholly formed by the distillation of sal-ammoniac, from common potash, and the simultaneous saturation of pure nitric acid by the ammoniacal gas liberated by the above process. We then put about a hectogramme (nearly two ounces) of this salt in a small retort, and placed it in a sand-bath. The salt melted and boiled some time before emitting any gas: at last the retort was filled with a white vapour which soon disappeared, and the gas immediately began to be libe- rated very rapidly; when we filled several bladders with it. In a short time the production of the gas ceased, and when we stopped the operation, almost nothing remained in the retort ; which convinced us that no accident had happened. Emboldened by this result, we put into a retort nearly three hectogrammes (about six ounces) of the same salt, which yielded enough of gas to fill seven or eight bladders, although we Jost a great part of it. The operation was continued equally successfully as at first, until nothing more remained in the retort ; but a circumstance occurred which surprised us all, and for which we could not account: this was the formation of an abundant red vapour in the inside of the retort in pro- portion as it cooled, although the last gas contained no nitrous gas; this we ascertained by suitable experiments. Effects On the Gaseous Oxide of Axote. ay Effects of the Gaseous Oxide of Azote when introduced into the Lungs ly Respiration. All those who have tasted or inhaled this gas agree that it has a taste strongly saccharine, the impression of which has been often retained during the whole day. I myself experienced also a ‘nitric taste (in truth, it was the gas lat- terly produced which I tasted). M. de M said, no doubt upon perceiving the same taste, that there was some- thing styptic in it. The rest did not perceive any thing else than a saccharine taste; which is certainly a very decisive one, considering the small quantity of matter which the gas could contain. The following is a precise account of the different cffects of the gas, as they were successively experienced by the va-— rious gentlemen who inhaled it. The gas was inhaled by means of a bladder with a stop-tock, the nostrils being held close, and the lungs emptied as much as possible. M.G suddenly lost all recollection at the third in- halation: he continued it for five minutes; after which he returned to his senses very much fatigued, without being able to recollect any other sensation than a sudden fainting, and a tingling in the temples. M. de M experienced a saccharine and styptic taste, a great dilatation, accompanied with a heat in the breast; his veins were swelled, and his pulse fell. Every object appeared to dance round before his eyes. He thought, how- ever, that he could have supported a stronger dose. The bladder was not large enough for his lungs. M. de P. experienced a saccharine taste at the first inhalation, which became afterwards imperceptible. His lungs were strongly dilated, and with great heat. He ex- perienced very agreeable sensations after laying aside the bladder, and he fell into involuntary fits of laughter. M.deS experienced the same saccharine taste as the former gentlemen, and the impression of it continued from ten o’clock in the morning until past midnight; he also ex- perienced vertigoes, and his Jegs remained benumbed al] day. M,. G——, 218 On the Gaseous Oxide of Azote. M.G , the same saccharine taste. After laying aside the bladder he experienced a dimness of sight, and after- wards a very pleasant sensation, which spread through his whole body. His legs were benumbed. M. de C——, a saccharine taste during the whole day, tingling in his ears, legs benumbed, the stomach almost choked up. Ubon the whole, he regarded what he had experienced as more painful than agreeable, Experiment. I was anxious to know in what degree the necessary con- straint of breathing in a bladder ieaceé the above results. These gentlemen, at my request, put themselves to the trouble of breathing common air in the same manner. They only found themselves mechanically fatigued; and all of them agreed in the same results. Another Experiment. I was also anxious to try the effect of oxygen gas. Those who inhaled it assured me that they experienced little differ- ence between it and common air, which consisted solely of an augmentation of heat in the lungs. Conclusion. Thus the singular effects above described belong to the gaseous oxide of azote alone. Second Meeting. The object of our second meeting was to repeat more at Jarge the experiments relative to the respirability of the gaseous oxide of azote, We put into a retort about eight hectogrammes (nearly 16 ounces) of the nitrate of ammonia prepared as at firsts a lengthening tube was adapted to a bottle with two necks, whence, by means of a tube of Welther, the gas proceeds into the tub. The retort rested on a sand-bath. Upon the first application of the heat the salt melted, and almost at the same time some reddish vapours were formed in the retort, but in very small quantity. The air of the vessels On the Gaseous Oxide of Azote. 219 vessels which the heat disengaged yielded also a nitrous smell to such a degree, that we were afraid of the success of the operation ; these vapours and smells, however, insensibly diminished, and at last totally disappeared. About -this stage of the operation, the bubbles which were disengaged had a manifest smell of the prussic acid, which continued a Jong time. At length the retort was filled with white va- pours, and the gaseous oxide of azote began to pass, which it soon did so abundantly that we removed the fire; and having again replaced the charcoal, the gas, which had ceased during the interval, reappeared in such abundance, that the luting gave way at one place. In spite of the Joss of a considerable quantity in consequence: of this accident, the disengagement of the gas mto the tub continued very rapidly during a quarter of an hour. This circumstance gave us reason to believe, that if the luting had not given way, there certainly would have been an explosion. Twelve persons submitted themselves to the experiment of inhaling the gas at this mecting, several of whom repeated it twice. It is right to observe, that the most of them had inhaled the gas at the last meeting, when two out of seven experienced a sensation of pleasure; but on this occasion none at all, and not even these two, experienced such a sen- gation. On the contrary, several suffered very severely. M. de M stamped with his feet all the time he held the bladder. After recovering from a profound stupor, he informed us, that he felt as if he had got a blow with a dag- ger on the back part of his head capable of killing an ox, and which he would not experience again for any thing in the world. The rest, in general, experienced vertigoes and dazzling of their eyes, which were succeeded in some of them by fits of laughter. I myself was of the latter number, and the following is an exact account of what I felt: At the first inspiration I emptied the bladder. A saccha- rine taste immediately filled my mouth and my lungs en+ tirely, which dilated considerably. I emptied my lungs and filled them again; but at the third trial ‘my ears tingled, and : I let 220 On the Gaseous Oxide of Azote. I let go the bladder. I continued an instant, without losing my recollection, rolling my eyes in a dumb stupor; I then burst into such a fit of laughter as I never experienced before in my life. After some seconds, this tendency to laugh ceased, as did also the other symptoms. M. de P experienced no other effect than a convulsive motion in some muscles of the face. But he had a violent diarrhea in the course of the day; and M. D——~ expe- rienced the same effects. Upon the whole, it would be very difficult to ascertain the effects of gaseous oxide of azote in an exact and general man- ner, since these effects vary in different individuals, and, what is very singular, even in the-same individual. M. de S——, who inhaled it four times, felt new impressions every time. For my own part, I only experienced a tendency to Jaughter in one of the several times I inhaled it. I should certainly have fainted had I pushed the experiment further, Effects of the Gaseous Oxide of Axote upon, Animals. I have only one experiment upon this subject, but it ap- pears worth reporting, I put a greenfinch into a glass vessel full of gaseous oxide of azote. The bird appeared to suffer nothing at first; but it soon closed its eyes, laid itself gently on its side, and ap- peared as if asleep. When brought into the open air and set at liberty, it placed itself on its legs, but did not attempt to fly away. It was submitted an hour afterwards to a se- cond experiment, and allowed to remain a little longer; but . no efforts could restore it to life. It appears very remarkable that this bird made no effort to get away, and that it felt no convulsions, as generally takes place in the other gases, XL, Re- f 921 J XL: Report of Cases in the Finsbury Dispensary, from the 1st of January to the 31st of March 1806. By Joun Taunton, Esq. Surgeon to the City and Fins- bury Dispensaries, and Lecturer on Anatomy, Physiology, and Surgery. Since last report (Phil. Mag. vol. xxiii. p. 312.) there have been admitted into this dispensary 160 patients. Cured * s - 66 Relieved - - 5 Irregular - - 3 Under cure - - 86 160 Of these, 33 have been visited at home, and eight have sub= mitted to operations. In the last surgical report (see January) there were 80 patients under cure, 70 of whom have been cured and 10 relieved, 18 have been home patients, and two have under- gone operations. Mrs. Cuffee, zt. 50, has been subject to rheumatism and asthma for several years. She observed a tumour in her left breast some years ago, irregular on its surface and occasion~ ally attended with darting pain, which was not severe, so as to excite much attention, till March 1805, when the breast had increased much in size, and was become very painful. The unfavourable symptoms continuing, she was admitted into the dispensary in November last ; but, owing to her bad state of health, nothing could be done at that time to remove the disease in her breast. In January, her health being im- proved, it was determined, in consultation, to propose the operation, that being the only mode of treatment likely to give her any chance for recovery. To this shé readily con- sented, and requested that an early day might be named for its performance. The operation was performed on the 28th of January, which she underwent with the greatest fortitude, and had very little symptomatic fever considering its magnitude: as she had naturally a very full breast, the size of which was much increased by the disease, the wound filled with granu- lations, 222 Report of Cases in the Finsbury Dispensary. lations, and was completely cicatrized in much less time than could have been expected from its size, as the incision was 14 inches in length, and a large portion of the integu- ments were necessarily removed. Mrs. F., zt. 31, has had several children, and ahways en- joyed good healih previous to the present discase. About the end of May she observed a tumour on the lower part of the neck, but, as it was not attended with muck pain, it did not excite much attention: from the beginning it appeared to be very hard and immovable, and, as it increased in size, it impeded respiration and deglutition. She was admitted into the dispensary on the 2ist of Sep- tember, when the tumour was become very painful both in deglutition and respiration, and, from its rapid enlargement, had much alarmed the patient. It was found to be an ex- ostosis of the clavicle, near its connection with the sternum. It reached to the upper part of the larynx, and its base where it grew from the clavicle was more than three inches iw fength, and it must have been more than nine inches in cir- eumference. In this case little was to be expected from any mode of treatment short of an operation; which must have been attended with great danger, as the tumour grew from the inner as well as from the upper surface of the clavicle, and was nearly in contact with the carotid artery. Cicuta fomentations were ordered with a view to alleviate the pain; in which they happily succeeded, and appeared to arest the growth of the tumour. She took the infusion of quassia, and the fomentations were continued till the 17th of October, when it was evident that the tumour had not increased, and the pain was much lessened during the above period. The emp. bydrarg. cum ammoniac. was applied, with a view fo increase the aetion of the absorbents: some magnesia vitriolata was taken occasionally, and the plaster renewed once in about every ten or twelve days: the tumour gradually decreased in size, was entirely discussed by the end of December, and she was discharged cured on the 6th of January 1806. Greville-street, Hation-garden, April 5, 1806. XLII. On { 223 ] XLI. On the Oxidation of Metals in general, and partici larly the Oxidation of Iron. Read in the French National Institute by M. THenarp*. As soon as oxygen was discovered, researches became ge- neral to ascertain its properties, and it was very soon dis- covered that this gas was the universal agent of combustion. Phlogiston was immediately exploded, and hypotheses to- tally contrary to experience were no longer resorted to in order to explain the generality of phenomena. By admit- ting the presence of this principle, more or less, in the me- tallic calces, an exact account may be taken of the angmenta- tion of weight which metals receive when calcined. But, - however simple this theory may appear at present, it was nevertheless the result of a grand effort of genius. When it was clearly demonstrated that metals, as well as other bodies, so far from losing their principles by combus- tion, absorbed a new one, because they are thereby aug- mented in weight; when Lavoisier taught us, that in this phenomenon, the cause of which was for such a long time unknown, the atmosphere was decomposed, and that one of its constituents formed a new combination, the properties of burnt bodies were examined with more care; a great number of new principles were discovered in such bodies, and in many of them the quantities of oxygen and of the radicals which formed them were determined. These new observations were again the source of many discoveries. It was seen that the same combustible body might be combined with oxygen in different quantities, and that consequently several oxides, as well as several acids, might have the same radical. Frequent applications of this principle are met with, particularly in the oxidation of metals; and at this period, lead, antimony, and manganese, offer the most re markable of these applications. It was this variety of oxides which led the author of the Chemical Statics to think that there actually was not so much difference as had been pre- viously believed between oxides of the same genus; and # From Annales de Chimie, tome lvi. ; this 204 On the Oxidation of Metals in generat, this led bim to believe, supported also by reflections which were the result of many experiments, that probably even metals pass from the metallic state to the maximum of oxy- genation by going through all the intermediate degrees of oxidation in such a manner, that for each metal there is a multitude of differeut oxides. I am well persuaded that the number of metallic oxides is much greater than most chemists admit, and that they do not pass immediately, as is supposed, at least with respect to some of them, from a weak degree of oxygenation to a very high one; that between these last theré exists one or more intermediate degrees which constitute as many particular oxides: but I confess that I am not yet convinced that there are as many oxides as possible degrees of oxygenation ; and if the theory admits them, experience seems to reject them : in fact, why should not these different oxides combine with acids ? The cause cannot be attributed to any thing else than that metals, at a certain degree of oxidation, have more af- finity for acids than at any other; but for that very reason it may happen, that, when combined with a given quantity of oxygen, they may form fixed oxides, while with a greater or less quantity these oxides can only have a momentary existence, The latter would therefore be placed between the former; there would be as many degrees througl which the former would be obliged to pass without being able to stop; and besides, this is exactly what we observe of acids which have the same radical. Will it be said, that between the sulphurous acid and sulphuric acid, between the phos- phorous and phosphoric acids, there are several intermediate acids? And if these intermediate acids do not exist; if sul phur, phosphorus, &c. cannot form any more than two acids, why do metals give birth to such a multitude of ox- ides ? why should not there be fixed degrees of oxygenation as well for the one as the other? In short, how couldit happen that hydrogen forms only one oxide, although susceptible of fixing more than five times and a half its weight of oxygen? There are many reasons which incline us to believe that me- tals are absolutely like other combustible bodies; aid al- though it is proved that the latter cannot form, with the ge- neral and particularly the Oxidation of Iron: 285 neral principle of combustion, a multitude of different com- binations, 1am persuaded that metals, which we regard with reason as analogous bodies, are not more susceptible than the others of a multitude of different decrees of oxidation. If we are permitted to entertain doubts on this view of the subject, we may certainly have some upon the nature of the oxides in their combinations with acids; and even if this struth had not been long admitted by chemists, some general observations would suffice to place the subject in a clear point of view. Let us take a glance, however, of each of these oxides, and attentively consider the oxides of iron, which are the principal objects of this memoir, Here every thing demonstrates, that in combinations of this sort the oxides are constant. Although cobalt, nickel, lead, zinc, gold, and platina, are all the bases of several oxides, yet in all the salts which they form they are always equally oxidated: thus the oxide is blue-in all the salts of cobalt, green in those of nickel; it is white in those of bismuth, zinc, and lead; and it is gray in those of silver, yellow in those of gold, and brown in those of platina: it varies, to be sure, in the salts of antimony, tin, mercury, copper, and ‘iron ; but still with several of them it is only certain of their oxides that can unite with acids. Two white oxides of an- timony alone are susceptible of this combination—the white volatile oxide and the white oxide of the second degree; the white oxide at the maximum is not attackable, except by the muriatic acid: still, however, if it is not ina state of very minute division, the muriatic acid dissolves it with great difficulty, and always by partly passing to the state of oxygenated muriatic acid. Tir, mercury, and copper, like antimony, do not form saline combinations with the acids, but under two states of oxidation; tin in the state of a gray and a white oxide, mercury in the state of a black and a red oxide, and copper in thé state of a yellowish white and a brown oxide. Hitherto it was thought that it was the same case with iron, and that in all the. salts which it was susceptible of forming, the oxide was always green or red. Some chemists; however, have admitted an intermediate oxide: they believed Vol, 24, No. 95. April1s06. P that 226 On the Oxidation of Metals in general, that there was also a yellow oxide, because ferruginous salts present themselves sometimes under this colour. Reasoning upon the hypothesis that all the metallic salts were always of the same shade as their oxides, they were necessarily led to adopt that idea; but it is now very well known that this method of viewing the subject is often erroneous, and that a salt is often white or red although its oxide is red or blue. Another salt, consequently, might be yellow, and have a red oxide for its base: this is exactly the case with all the yellow salts of iron. Besides the green and red oxide, how- ever, there exists another oxide of iron which performs a very important part in the ferruginous saline combinations ; and as, on the one hand, the formation of several produc- tions manufactured in the workshops, and, on the other hand, as the explanation of several phenomena, which often present themselves in the arts, depend upon the existence of this ox- ide, I think it my duty to enter into some details respecting it. It is formed when iron is treated with most of the acids ; and we obtain it by decomposing by means of potash, soda, and ammonia, the various salts so formed. Above all, by means of a solution of iron in sulphuric acid we may easily demonstrate its existence. If in this recent solution we pour some alkali, a white precipitate is formed, which becomes speedily green at the surface and soon passes to a red co- lour*. These changes of colour, which take place in the whole mass if it is agitated, are evidently produced by an absorption of oxygen; because, in repeating the experi- ment in a fiask, the air which it contains sensibly diminishes in volume, and soon extinguishes a taper plunged into it, when the white oxide has become green, and with greater reason when it has passed to the red. It is this white oxide, hypersaturated with sulphuric acid, which forms, in a great measure, the sulphate of iron used - * Tpoured some hyperoxidated sulphate of iron into a great excess of caustic potash, and I always observed a white precipitate. 1 even boiled the mixture in a retert the neck of which was plunged into water; the oxideibe-- came green, and was even red at the surface; but the lower part was always perceptibly white, although it contained no sulphuric acid. Of this I con- vineed inyself by washing it, dissolving it in the muriatic acid, and by adding Hitrate of barytes to it, : . in did particularly the Oxidation of Iron: $07 in Commerce. Nevertheless, besides this combination, the white oxide may still form a sulphate much more acid; and then, instead of being of a dark green, the compound ap-' proaches to a clear emerald green. ‘Thus we find there is a green oxide as well as a red oxide of iron ; each of them, on being united with sulphuric acid, gives birth to at least two very distinct salts. Let us row proceed to examine these SIX kinds of sulphate of iron. a I shall distinguish the first of them by the ames of aci- dulated sulphate and acid sulphate of white iron, because the oxide in these is colourless, arid the one miich more acid than the other; the second, for the same reason, under the names of acidulated sulphate and acid sulphate of green iron; and the third, for the same reason, I shall term neutral and acid sulphates of red iron. - The acidulated sulphate of white irdn is obtained by boil- ing sulphuric acid diluted with water upon an excess of iron filings or turnings. When dissolved, or in particular cry~ stallized, it is always of a bottle green, and the more co- loured it is, the more ‘is it esteemed in commerce. It in- stantly loses this colour upon an addition of sulphuric acid 3 it then takes an emerald green and becomes acid sulphate of white iron, which alters blue colours much more than the former*: it is then less fit for the operations of the arts, and rejected by manufacturers, who give a preference to the for- mer, not from prejudice, but founded on the nature of saline * When sulphuric acid is poured into a solution of acidulated sulphate of white iron, evaporated in such a manner-as to mark 36° to the weight of the liquor, it almost immediately forms an abundant whité and crystalline pre- cipitate, which is nothing else but acid sulphate of white iron. This is the reason why; in vit ect vel re will be Se 012. = 054, and 55.2 036 respectively The same Property of Vision demonstrated otherwise. Thas, let 2 represent the sine of incidence, and p and g the sines of refraction, as before. The sine of incidence of every ray is to its sine of réftac- tion in a given ratio *, And the sine of incidence of the extreme ray PA varies. with the aperture of the lens: for n becomes less as PA approaches the axis of the lens Ev. Therefore the sines of refraction p and q, and the angle xAy, and its subtense xy, increase or decrease with AB: consequently, the image of the sun or moon upon the retina increases or decreases in magnitude with the pupil of the eye. Now as-the rays of artificial light dre didienenils refrangi- ble, it is evident from the given ratio of AB to.xy, in which they increase or decrease at the same time, that the image of a candle formed in the focus of a convex lens decreases with the aperture of the glass. For the rays of the sun and the light of a candle are both governed by the same law in the formation of images in the focus of alens ; but this law does not obtain in the same de egree in both objects, in con- sequence of the rays of the latter being in a more- diverging state than those of the former. Experiment I. To prove the truth of this theory by experiments I took two double convex lenses, each four inches in diameter and: * Newton's Optics, p. 64. 24 inches Apparent Magnitude of the horizontal Moon. 243 24 inches focal distance, and fixed them in a frame close to each other in the same plane. This instrument I placed in a perpendicular direction, with a white screen behind it, to receive the images of a lighted candle that stood before it at some distance. The screen being moved until the two images of the candle were seen very distinctly upon it, they appeared exactly of the same magnitude; but when the aperture of one of the glasses was contracted to an inch in diameter, the image of the candle’ formed by that lens ap- peared three or four times less than the image formed by the other; and as these two images were seen at the same time, the eye could judge more accurately of their dimensions than of the apparent magnitude of the mvon near the ho- rizon and on the meridian. But when I moved the screen until the circular spot of light or spectrum formed by the Jens of four inches aperture measured one inch in diameter, the spectrum formed by the oiher lens measured only one quarter of an inch; and as the screen was moved from the glasses by slow degrees, the spectrums decreased in the same ratio, until two perfect images of the candle were formed. Experiment I. In order to exhibit a more exact representation of the phenomenon, I had a frame made to contain seven convex lenses fixed in the form of a semicircle. They were all of the same focal distance, but not of the same aperture. The two Jargest apertures measured each 1°2 inches; these were to represent the pupil of the eye when viewing the moon at her rising or setting; the two next to these had each an aperture of 0:6 inches; the other two were still less; and the single lens at the top.of the curve had the least aperture, to represent the pupil when the eye is exposed to the moon on the meridian. This instrument being fixed in a perpendicular position, with a candle before it, as in the preceding experiment, and the screen brought to a certain distance within the focus of the glasses, the spectrums upon it appeared in the same ratio to each other as the glasses that formed them. Fora representation of these spectrums see Plate VI. Q2 Hence 944 Production of Muriatic Acid and Soda Hence the cause of that. variation which obtains in the apparent magnitude of an object, is no longer a matter of mere opinion; for it is an established law in dioptries, that the. image in the focus of a convex lens increases with the aper- ture of the glass, and consequenily, the picture of the moon in the focus of the crystalline lens of the eye increases as the pupil is enlarged. I am, sir, Your humble servant, Ez. WALKER. XLIV.. Extract of a Letter from M. Leorovd pr Bucu, of Milan, to Professor PicrrT, of Geneva, on the Pro- duction of Muriatic Acid and Soda by the Galvanic De- composition of Water *. SIR, Milan, October 6, 1805. I HAVE a few words to say on the subject of a fact which at present occupies the attention of the Italian philosophers, and particularly Volta. It is the experiment whereby we compose the muriatic acid and soda by means of the Gal- yanic action. We have been told that this experiment, for which we are indebted to Dr. Pacchiani, has not sueceeded at Genevat. The following is the method to make it suc- ceed at all times : Have two piles, the one near the other, and joined to- gether at the base, in such a manner, that the positive pole of the one and the negative pole of the other shall be at the superior extremities of the two piles. Conduct a gold or platina wire from the negative pole (of zinc) into a tube A, slightly closed at the top by a piece of linen or a cork, through which the wire passes in descending down ahout two-thirds of the tube. Make another wire of the same substance also descend from the positive pole (of copper) into a tube B, disposed in the same manner as the preceding. Plunge both of them imto a drinking-glass containing di- stilled water. Oxygen will be disengaged in the tube B, and * From Bibliotheque Britannique, vol. xxx. 4+ We do not believe it was ever tried at Geneva.PicTer. hydrogen Ly the Galvanic Decomposition of Water. 245 hydrogen in the tube A. Allow the apparatus to work, and a few hours will furnish unequivocal marks of the existence of the muriatic acid in the tube B, which had allowed oxy- gen to escape, and of soda im the tube A, which retained it. At the end of ten or twelve hours, nitrate of silver, poured into B drop by drop, precipitates itself abundantly. If the water of the two tubes is mixed together and evaporated, a sensible quantity of muriate of soda is obtained. If the ex- periment is made in the dark, the acid obtained in the tube B is oxygenated. The citron yellow colour is very striking; the smell of the acid cannot be mistaken ; light decomposes it. The tubes must not be too narrow; they ought to be six or eight lines in diameter: without this precaution the experiment will not succeed; because the current, in order to pass from B to A by the inferior orifice of the two tubes plunged into a bad conductor, which is water, requires a cy- linder of a great enough diameter in order to carry, in a given time, a sufficient quantity of electricity into the tubes. The Jatter must not be too far from one another; they will be at a convenient distance in a flat-bottomed drinking-glass. The oxygenated acid soon attacks the gold. If evaporated, we ought to have a fine purple of Cassius* for a residue. Has any thing been discovered for a long time more perplexing or more remarkable? The discovery of soda belongs to Mas- cagny, of Siennaf. I have the honour to be, &c. Lrorouip pv Bucu. * The author is here in an error. There can be no precipitate of Cassius formed without the presence of tin.—Epir. + The production of soda by the Galvanic action is a new fact ; but that of an acid (then supposed to be the nitrous acid) belongs to Cruickshank: he announced it very learnedly in a memoir entitled ** Additional Remarks on Galvanic Electricity,’ published in Nicholson’s Journal for 1800. What M. de Buch has here said relative to certain conditions of manipulation, with- put which the experiment did not succeed, will perhaps explain the reason why Messrs, Biot and Thenard met with no success in their attempts to repeat, —Picrer, The production of soda by the Galvanic decomposition of water, was an- nounced in The Philosophical Magazine so far back as the month of April last; that is, exactly ayear ago. M. de Buch’s letter given above is dated in October; and the number of M., Pictet’s Journal, from which we have copied it, is that for November last. ‘The first discovery, therefore, belongs to Mr, Peel. See our xxist yolume, p. 279.—Enir. Q 3 XLV. Twenty~ f 246 J XLV. Twenty-seventh Communication from Dr. Tuorn- TON, relative to Pneumatic Medicine. To Mr. Tilloch. No. 1, Hinde-street, Manchester- DEAR SIR, square, April 2, 1806. T HE following cases of catalepsy and epilepsy are of con- siderable importance, and merit a place in your philosophic journal, ; Case of Catalepsy cured ly Vital Air. Miss Lavinia de Yrujo, xt. 10, -lives at Mrs. Baylis’s, Brook Green House, Hammersmith. She had a fit at three years old: then her mext attack was when five years old: when eight, they would attack her twa or three times a week, She used to faint; and her eyes became fixed, her fingers clenched, and all her limbs completely rigid; the eyes would remain wide open and fixed: this would continue a quarter of an hour. The last fit, before she applied to me, was in October 1804, when it came on at two and continued till seven. Mr. Flower was sent for, who judiciously employed the usual restoratives, aud advised the young lady to be sent home for further advice. She began the inhalation of a gal- lon of vital air, diluted, once a wie with the usual tonic remedies ; and has not had a fit now, September 16, 1805, aw hole twelvemonth. She only took the vital air for three w ceks, and has not had any medicine, or the least occasion. for any, since. She is now before me, with her mother, perfectly well; and is returned to her school at Hammer; smith. The apothecary to the family, and several other medical gentlemen, had pronounced, to the mother and fa- oily, this case as one that never would be cured by art. Observations on this Case by Dr. Thornton. 1. These cases yield to the vital air when all other reme- dies fail. The cause is, that the vital air gives energy to the muscles, and thence to the nerves, taking off inordinate ac- tion from an undue balance of principles. 2. And hence it is, that persons breathing much bad air become, on the contrary, conyulsed. Iam, &c. RoBerT JOHN THORNTON. XLVI. Twenty- [ 247 J XLVI. Twenty-eighth Communication on Pneumatic Medi- cine, sent by Dr. THoRNTON, from Mr. Hiri, Surgeon. Case of Epilepsy cured ly Vital Air, (RRS Wayre Dans, son of Mr. Dare, Dowgate Hill, is a young man who appeared strong and healthy until eleven years of age. At that period, being very abruptly informed that his father’s house was on fire, the shock affected him so much as to throw him into an epileptic fit. From this time the paroxysms failed not to return every three or four weeks; and though, during the course of some years, the number of his fits did not much in- crease, his bodily strength and mental faculties were con- siderably impaired. Several medical men were consulted on the first attack, but the remedies prescribed by. them gave little or no relief. On his becoming deaf in one ear, and his eyesight failing him, whatever he learned at the Blue- coat School was forgotten, owing to the viclence of the fits. His parents, therefore, thought it advisable to take him home. At length, having received soine benefit from medical aid, his father placed him on trial at Mr. Davison’s, in Sise- lane; but a fright soon bringing back all his former disor- ders, he was obliged to return again to his family. fis fits were now exceedingly violent, and their frequency increased to a considerable number in twenty-four hours. In conse- quence of tiis he became more. deaf than ever, his vision weaker, and his intellects so materially injured that it was impossible to leave him alone, for fear he should either fall into the fire, or meet with some other calamitous accident, In this truly deplorable state he was put under my care early in March 1796. The morning previous to my seeing him, his fits had been so particularly violent as to exhaust him greatly, and his pulse beat above one hundred jn a minute, It was not without infinite difficulty that I could either per- suade hiin, or make him comprehend in what manner, to inhale vital air from my apparatus; and the general torpor of his mind, extreme debility of body, and deafness, gave Q 4 me 248 Twenly-eighth Communication from Dr. Thornton, me but faint hopes of his recovery. Howeyer, after he had inhaled a moderate dose of vital air, an unusual warmth dif- fused itself over his whole frame, accompanied with a con- siderable degree of perspiration. He afterwards passed: the whole day, and the following night, without any return of fits; a circumstance whith! had not happened for several months. The next morning he was tolerably cheerful ; his hearing and vision less defective; and his pulse more firm, beating ten strokes less in a minute than the preceding day. On having again recourse to the vital air, it revived him as before, and the second day passed without a fit: but he found a disposition to fulness in his head, and such a ten- dency to falling down during that day, that it would have taken place, had not his own exertions prevented it. The third morning, before he came to my house, he was attacked with a very slight fit. Finding in him this tendency to local fulness in the head, I ordered cupping, and an opening me- dicine. By paying due attention to the fulness in the head, and keeping the bowels properly open, the pulse became re- gular; while the active effects of the vital air so inyigorated his constitution, that he not only lost his fits, but in six weeks gradually regained his vision and hearing, and was able to walk six or seven miles a day, without fatigue, or any inconvenience whatever. Some sultry weather coming on in the month of May, he became nervous; had ‘the head- ach, and some slight degree of fever, after a fatiguing walk to Hampstead; and for the second time only experienced a trifling relapse. I now directed him to be bled with leeches on the temples, and to take the usual dose of opening me- dicine; after which, as soon as the fever had subsided, he was to have recourse to the bark and vital air, at different intervals, until the middle of July. He then became per- fectly well in health, strength, and spirits; and in Decem- ber 1797 bis father engaged him as clerk to Messrs. Hop- kins and Lincoln, in Barbican, where ke now resides; and, not having had any return whatever of his former com- plaints, he is fully enabled to keep such accounts as require a mind perfectly free from every degree of oppression or it- ritation, &« Te relative to Pneumatic Medicine. 249 6° To Mr, Hill, Ff SIR, © T can witb pleasure inform you, that my son, Charles Wayte Dayre, has, by the blessing of God, with your kind attention to him, and the help of vital air, received a very great cure from his fits, deafness, and nervous complaints, which had long affected him; and they increased on him so fast, that, when he applicd to you, he had from sixteen to twenty aday. Hecould not be left at any time, even a quarter of an hour in a day. He has not had a fit these eighteen months, or near two years. +e] Amn... Sits Your greatly obliged humble servant, «* CHaRLes Dare.” Observations on this Case by Mr. Hill, However the general appearance of this young man may have been as to strength, some peculiarity of habit, as irri- tability of stomach and bowels, most likely had existed, and was a predisposing cause of the complaint. Be this as it may, any sudden surprise or misfortune will almost always produce some determination of blood to the head, more or Jess violent, in the strongest frame. In this case, as in many others, it Jaid the foundation of very serious mischief, In length of time it exhausted the nervous energy ; and the powers of life, depending on an equable circulation, were reduced to extreme debility, Under these circumstances no remedy, one short instance excepted, arrested the progress of the disease, still less gave hopes of a recovery. The suc- cess in this case was beyond nry expectation ; for I was ap- prehensive that the several organs of sense, as the eyes and ears, were become paralytic from some organic defect in the brain, owing to the long continuance, violence, and fre- quency of the attacks. Contrary to my conjecture, how- ever, the patient was relieved much in the same manner as the subject of the preceding case; and, as the same conse~ quences followed, nearly the same reasoning applies to both; Viz. 250 On the Electrogene of Schmidt. viz. some accumulation in the system being removed by the chemical union of vital air in the blood, the secretions by the skin and kidneys being promoted, and the energy and strength of the nerves being restored, then tonic remedies recovered the chylopoietic viscera to their due functions. I cannot avoid particularly observing, that this lessening of the determination of blood to the head, is a fact of great importance to all people subject to fits or nervous head- aehe. XLVII. On the Electrogene of Scamipr. By Count StERN- BERG, Vice-president of the Electoral Regency of Ra- tiston*, A GREAT deal has been said, for a year past, of M. Schmidt, a chemist of Breslau, who insists that he has merited the prize of sixty thousand francs, which ought to have been decreed to the author of the best discovery upon Galvanism. The following is a succinct account of what has been pub- lished on the subject, extracted from a letter addressed to M. Nauche, the physician, at Paris, by count Sternberg. M,. Schmidt thinks he has discovered a body capable of generating electricity, which he calls e/ectrogene. This body serves, with caloric, to combine the two constituent princi- ples of the air—oxygen and azote. Its affinity with them is weakened by the presence of the solar rays. The latter aug- ment, on the contrary, its affinity with water: this is the reason why, in spring, electrogene partly quits the air to unite with water, elevated by meanis of caloric, in the form of elastic vapours, The degrees of intensity of the unjon of electrogene with air and water are very variable, and thence proceed the va- riations in the elasticity of the atmosphere, The sea, by surcharging the atmosphere with aqucous va- pours, absorbs electrogene, which endeavours to maintain an equilibrium. For a contrary reason, the earth tends to give the air a part of its electrogene. This alternate combination and * From Billioth. Phys, Economique, no, 4. an 14. disengagement On Sonorous Vibrations. 251 disengagement produce, by their succession, winds and clouds. All the metals contain electrogene, and they do not oxi- date but in regard to their afhnity with it. It is the cause of crystallization by the dry method. The weakening of the affinity of electrogene with the bases of the air, by means of the solar rays, eives birth to vegeta~ tion. Animal life is also attributed to electrogene. It enters with oxyen into the blood of animals by respiration ; it is decomposed by this fluid, and its elementary base con- stitutes, in the brain and the nervous system, the principle of irritability. M. Schmidt attributes still other effects to this new being; but he does not distinguish them well enough from those of caloric, oxygen, and attraction. His theory, although curi- ous, is not sufficiently supported by. facts to entitle it to much attention. eee Pee Se XLVI. Letter of M. Onstep, Professor of Philosophy at Copenhagen, to Professor PicTET of Geneva, upon Sono- rous Vibrations *. SIR, Copenhagen, May 26, 1785. Tae impartial interest which you take in every thing tend- ing to accelerate the progress of science, has made me desirous, for a long time past, of establishing a correspon- dence with you. I take the opportunity of a traveller going to Geneva, to deliver to you the results of some of my re- searches in physics. I have chosen as the subject of my present letter, the experiments I have repeatedly made, upon the effects produced in the interior of solid bodies during the propagation of motion. I have been led to these re- searches by both antient and modern observations upon sound. Every body is acquainted with the interesting dis~ ® From Billiotheque Britannique, vol. xxx. covely 952 On Sonorous Vibrations. ' covery of the celebrated Chladni, who taught the art of pro- ducing certain figures, by covering with sand plates of metal or of glass, and then rubbing them upon the edge with a violin bow.’ - The «sand is put in motion by the effect of the oscillations of the sonorous body, and the grains of it, quitting certain parts of the surface, heap themselves up upon the others, by forming lines and figures of different forms. The lines into-which the grains of sand heap themseives up, are without doubt the points of rest between the portions of the surface put in vibration by the rubbing of the bow upon the edges of the plates. Modern philosophers think they have found, in these curi- ous results, a confirmation of the opinion which tends to exclude those internal vibrations, formerly supposed to be the cause of the phenomena of sound, and to refer the latter merely to those oscillations which are visible and appreciable by their mechanical effects, of which the experiment upon sand gives an example, It appears-to me, however, that the antient hypothesis has been abandoned too easily, at least my experiments have rather led me towards that hypothesis, than removed me from it. The following are the observations which these experiments have suggested to me : Ttis allowed that in common air, a fluid eminently elastic, a sudden compression is followed by a reaction which pro- duces a dilatation, which immediately compresses the neighbouring particles, and the effects of a first concussion propagate themselves in this manner to an indefinite extent, But Fdo not see why this does not take place also in elastic solids, when they are made to produce a sound. The ex- periments of Chladni, although in other respects very curi- ous, are not proper to prove the small vibrations which con- cur to form the undulations from which the figures in ques-, tion result, and for the knowledge of which we are indebted to him, Sand, which is made use of by him, is too large grained to indicate the nature of the movement of the solid molecule which tremble under it; and what is still worse, these grains are elastic, so that they do not remain where they \ On Sonvrous Vibrations. 253 they fall, but fly about ; this hinders them from pursuing a regular progressive movement, like that of sonorous undula- tions. It was on this account that, on varying my exper’ ments, I thought of substituting in the place of sand, a more attenuated matter not possessing the inconveniences I have mentioned ; this was semen lycopedii, or the seeds of club- mess. After having covered a plate of metal or glass with this substance, I tried to produce a sound in the manner of Chiadni, and in an instant I saw the dust distribute itself in- to anumber of little regular tumuli, which put themselves in motion at their extremities, or formed the figures discover- ed by this naturalist. They always range themselves in the form of acurve, the convexity of which is in proportion to the point touched by the violin bow, or towards the point which has an analogous situation: the nearer that each of these little heaps is to these points, its height is the more considerable; this gives to the whole a remarkable regularity. The experiments of M. Chladui are astonishing at first sight, on account of the regularity of the figures produced by a single stroke of the bow, which appears as if done by magic. My experiments have not the same charm; but perhaps they are more instructive, on account of the com- parative slowness of my process, which admits of their effects being more advantageously studied. We observe that the interior of the small elevations formed in my experiments continue in motion during the continuance of the sound. The duration of these vibrations, although very short, is ap~ preciable on plates of three or four inches diameter : it is Jonger when plates of a larger diameter are employed. I often made use of a disc of metal of six inches diameter : in this case I always saw the small elevations change their ap- pearance at different epochs of the duration of the sound. At one moment the height increases,.and at another it di- minishes, and the dust has the appearance. of arranging itself in small globules which roll one above another: we easily perceive that all these phenomena are still very com- plicated. The movement of the grains is in part vertical, in part horizontal ; the horizontal movement. is composed. of two others; one of the forces impels the grains forward, and 1 the 254 On. Sonorous Vibrations. the other drives them to the two sides. I was anxious to ex- amine, as minutely as possible, each of these movements by itself, and the following is what I remarked. I held a square of glass in: such a manner that two or three of the edges of it were in contact with my fingers. I struck the edge which I did not touch, with a piece of smooth wood, in such a manner that every point received the shock at the same instant. In this case, the powder arranges itsclf in -lines parallel to the edge struck upon. These lines are rarely straight, because these edges have always irregularities 5 the straightest I ever saw were produced upon ‘an iron rule, struck with a smooth piece of the same metal: in order to the better success of this experiment, it is necessary that the square or the rule should rest upon a smooth table. IfI do not strike the blow upon the whole edge, but only upon some of its points, other lines are formed parallel to the direction of the blow, and perpendicular to the edge struck. These lines seem to be composed of a crowd of small eleva- tions, less regular than those produced when plates covered with the dust are struck with the fiddle bow. This experi- ment succeeds with difficulty when the whole of the plate is allowed to rest upon a table, because this circumstance pre- vents us from striking a good blow. In short, if I struck the plate in a direction perpendicular to its plane, the dust arranged itself in little regular heaps. In the former case the undulations proceed forward; in the second case, they take place both in a forward and a lateral direction ; in the third case, they proceed in every direction, because the com- pression produced by the blow perpendicular to the plane, propagates itself as well horizontally as vertically. The tone produced in the first case is very low; that of the second is much more clevated ; but that of the third is still much more elevated; and it is the only one which deserves to be called a tone, or a sound appreciable in the musical scale. One would suppose that the change produced in elastic bodies, by the communication of motion, could scarcely be limited to the simple mechanical displacement of the part, but that in this modification it ought to have some other more On Sonorous Vibrations. 255 more intimate action. Every kind of friction produces not euly heat, but electricity also. De Ja Place, and Biot, have already attracted the attention of philosophers to the first of these phenomena; I am of opinion that the latter of them requires much more attention. J always found in my ex- periments that sand, or dust, adheres much more to those parts to which the movement of the sonorous bodies had: fixed it, than it did to the other parts. I have often thrown tiesb sand oyer a plate of glass, upon which I had already produced a figure. I shook it gently after having reversed it, and I always remarked that the sand which formed the figure remained adhering, while the other part detached it- self. The adherence of grains finer than those of sand is very remarkable. I also discovered, with the assistance of. Coulomb’s electrometer, indications of electricity in those plates which had emitted a sound; but I haye not repeated: these experingnts sufficiently to enable me to detail them. I discovered on the above occasion, that the edges and angles of bodies act upon Coulomb’s electrometer almost _ always; and I propose to myself a new course of experi- ments upon this subject. The celebrated Ritter, to whom T had communicated my experiments upon the part which electricity acts in the phenomena of sound, had long ago discovered that the electrical pile of Volta is capable of pro- ducing sound, when a shock is received from it in the ears. In a work about to appear under the title of ‘* A System of Electrical Bodies,’ this great philosopher makes it clear that a body acquires positive electricity by compression, and negative by dilatation. Thus we may say, that there are in each sound as many alternatives of electricity, positive and negative, as there are oscillations ; but the union of two elec- | tricities produces a commotion: thus there are in one sound as many extremely weak electrical commotions as there are oscillations. Each of these insulated commotions would be absolutely insensible; but when receiyed in a very great number, in a period too small to distinguish the one from the other, they always produce a sensible effect, especially since positive electricity renders the organ more sensible for the negative than it was before, and vice versd. The 256 Use of the Sutures in the Skulls of Animals. The sensible effect of the union of all these insensible com- motions is sound. I confess that these ideas of M. Ritter appear contradictory to all the received opinions on the organ’ of hearing ; but it must also be confessed that our knowledge of all the organs of sense is as yet imperfect. I am of opinion, however, that the theory of M. Ritter agrees per- fectly well with the antient hypotheses. As for my own experiments, they may be easily repeated by any person, and some oné perhaps may discover more than I have here de- scribed. XLIX. On the Use of the Sutures in the Skulls of Ani- mals. By Mr. B. Greson*. Tae full use of the singular junction of the bones of the skull which is called suture, has, from the earliest periods of anatomy and surgery, attracted the attention and eluded the researches of the physiologist. To this remarkable feature in osteogeny, in a great measure peculiar to a certain period of life, many uses have been attributed. Some of these are totally erroneous ; such as that for allowing the transpiration of moisture, to keep the brain cool and fit for thinking ; for giving a more strict adhesion of the dura mater to the inner surface of the skull ; for admitting a more free communica- tion by blood-vessels between the external and internal parts of the head ; or for affording interstices, that the bones may be pushed asunder by the growth of the brain, lest’ that or- gan should be cramped in its growth, in consequence of the comparatively slow growth of the bones of the skull. Other uses attributed to the sutures are merely slight ad- vantages derived from their structure, which are enjoyed in early infancy, or till adult life, but gradually cease after that period. Thus at the time of birth the loose union of the bones of the skull accommodates the shape of the head to the figure of the different parts of the cavity through which it passes. At adult age, when the sutures are fully formed, * From Munchester Transactions, second series, vol. i. they Use of the Sutures in the Skulls of Animals. 257 they may occasionally check the progress (if I may be allowed the expression) of a fracture nearly spent ;—or vibrations, communicated to the bones of the skull, will be propagated with less force to the brain, in consequence of the bones being separated at the sutures. It is, however, abundantly evident, that these are not the main purposes for which the sutures are formed; otherwise they would not begin to be obliterated at a period of life when they would perform these offices more usefully than ever. Consistent with this remark, we shall find that the true pur- pose for which they are formed, and the particular process with which they are connected, is fully completed before their obliteration takes place. When we take a view of the mode of junction hetween many bones and parts of bones in the human body, which do not admit of motion, we find that with little exception they-all agree in this particular; that sconer or later the car- tilage or periosteum, which once was interposed, ‘s obliterat- ed, and these different portions, or entire bones, coalesce. The separate portions, which originally compose the ver- tebre, are early in thus uniting: after these the sides of the lower jaw ; at a later period the epiphysis of a cylindrical boneis united to its body: and still later the bones of the skull usually coalesce, and the sutures are obliterated. Other bones, as those of the face, which have no motion and sustain little weight, are irregular in this respect ; sometimes uniting, but generally remaining distinct to the end of a long life. The original formation of the osseous system in several distinct pieces, respects principally its speedy ossification at an early period of life, and its future convenient extension, tillit bas arrived as its full growth; and we may consider it as a general principle, that where two parts of one bone are separated from each other by an intervening cartilage, or two distinct bones merely by periosteum, at that part osse- ous materials are added to increase their length or extend their superficies. This we shall find takes place, whether the junction be effected by comparatively smooth surfaces, as between the body of a bone and its epiphysis ; or between Vol. 24, No. 95. April1so6. = R the 258 Use of the Sutures in the Skulls of Animals. the bones of the skull by jazzed sutures. Hence it appears that the bones of the body gencrally are increased in length or extent, not by a uniform extension of the whole sub- stance, but by an addition of bony matter in some particular part. | ee Thus the body of a cylindrical bone is lengthened by ad- dition to each end. This we might conclude would be the case, from considering the part in which its ossification commences: as this commences in a middle point and pro- ceeds to each extremity, it is natural to suppose that its growth still goes on in the same direction, or continues at the extremities. That this is the case we know, not by reasoning alone, but by a direct experiment. Mr. Hunter sunk two small pieces of lead in the middle of the tibia or shin bone of a pig, and measured accurately the distance be- tween them: on examining the animal some time after= wards, it appeared, that though the bone had increased con- siderably in length, the pieces of lead still remained at the same distance from each other that they were before. From this experiment we learn, that a cylindrical bone is not ex- tended in its middle, but is lengthened by addition to its ex- ‘tremities, where the body of the bone is joined to its epi- physis; the chief intention of the epiphysis being to allow the intervention of a vascular organ, which may convenient- dy deposit bony materials, without interfering with the joint, Stself. As cylindrical bones are lengthened at their extreme parts, we are led by analogy to conclude, that the same general plan is pursued in the extension of the flat bones of the body: and although we have no direct experiment by which this has been proved, there are circumstances which leave little doubt but they are extended by addition to their edges. ‘Vhus, to take the parietal bone as an example ; as ossification begins im a central point and extends towards the cireumfe- rence, it is probable that, to the completion of the process, it ‘continues to gv on in the same direction; and the same circumstance taking place in every bone of the cranium, it is probable, that even after the whole of the brain is incased 933 ip s Use of the Sutures in the Skulls of Animals. 259 in bone, the addition is still made at the edge of each, and that the general enlargement originates where they are all mutually joined by the sutures. Of this process I had a very striking illustration some years ago. Ina young subjecty from what cause I know not, the deposition of osseous matter had been sitddenly increased a short time before death. It was in different stages of progress, but had taken place in all the bones of the body which I preserved ; in some par- tially, in others generally. In all, the new osseous matter was elevated above the level of the bone, upon which it was placed. In some parts of the parietal bones it was only in its commencement, and put on the appearance of a net~ work, similar to that which may be observed in the same bones at an early period of their formation. In other parts the meshes of the net-work were more or less filled up ; in others again completely, so as to put on the uniform appear- ance of solid bone. The same reticulated appearance was evident on the edges of all the bones of the skull, where they form the sutures, and at the extremities of the cylindri- cal bones, between the body and epiphysis. The same ap- pearance of increased deposition was seen on the surface of the cylindrical bones, with this difference, that the meshes were not circular, but oblong squares ; so as to put on more of the striated appearance. In some parts, the newly secreted bone was easily separable from the general mass, and formed a thin layer externally, affording one of the best proofs I have met with, of the increase of cylindrical bones in thickness by deposition externally, whilst a corresponding internal absorption goes on. From the striking similarity of appearance on the surfaces and edges of the bones, we may safely conclude, that the same process of deposition was going on in both, and may thence infer, that the bones of the skull are increased in extent by the deposition of osseous matter at their edges, or where they are joined to each other by suture. This fact points out to us, in a great measure, the real use of this peculiar mode of junction. In order that the bones of the skull may be increased in extent, it is necessary that they should he retained at a cer- tain distance from each other; that.the.periosteum with its Ra vesgels 460 Use of the Sutures in the Skulls of Animals. vessels may pass down between them, free from compres- sion, and secrete the osseous matter. At the same time, the thin bones composing the upper part of the skull, resting as an arch upon its basis, must be united together so firmly, as not to be separated by common degrees of violence. For this purpose, projecting points from the external surface of each bone are reciprocally received into corresponding niches; which only penetrate through one half of the thickness of the skull, and form an irregular kind of dove tailing. Two advantages arise from this structure being superficial, and confined to the external table of the skull. _ The pro- jecting points from each side, resting upon the solid surface of the internal table’ of the opposite bone, cam resist more effectually any violence which might tend to force the bones inwards ; and the internal part af the skull presents, by this means, a smooth surface to the coverings of the brain; for internally no appearance of a jagged suture is seen. From this view of the subject we see, that the sutures of the human skull, by their peculiar formation, at once unite the bones together,.and so far separate them, as to allow the interposition of a vascular organ by which their superficies is gradually increased to its greatest extent.* This explana- tion * Since this paper was written in the year 1800, I have found, that a simi- far opinion was published by Professor Soemmerringin 1794,in his valu- able work, “ De corporis humani fabrica.” ‘To him, therefore, any credit which may belong to the primary suggestion of this use of the sutures is due. As his opinion, however, has been little noticed by anatomists generally, and: is placed in a clearer point of view by the facts which suggested this further explanation of it to me; it has not been’thought improper to give this essay a place in these’ Memoirs. But whilst the reader will see, by the following quotation, the near resemblance between the opinion of Professor Soemmer- ring and that which I have brought forward, I hopethe character of plagiarist or compiler will not be attributed to me. ‘© Usus horum sic sese habentium terminorum ossa eranii inter bene liquet. “ Incrementum ambitus calyarix levant, ni enim inter ossa capitis mox post partum suture interponerentur, hxe‘crescere non possent, ‘nisi alia ratione natura rem institueret. Tali igitur modo incrementum ealvariz cum inere- inento reliquorum ossiam convenit ; initio enim suturis, vel potius lineis car- tilaginosis ossa iis locis'¢onglutinantur, verum tamen non nisi in embrionibus ad \ Use of the Sutures in the Skulls of Animals. 261 tion of the use of sutures comprehends and accounts for those foncomitant circumstances, which were considered by older anatomists as their real use; and, as far as I can see, is not contradicted by any fact connected with them. If it be asked, for instance, why at the sutures there is a stronger adhesion of the dura mater internally, and perios- teum externally, than in other parts of the skull ? the answer is, that these membranes with their vessels are continued in- to the sutures, to form conjointly the secretory organ by which the bones are extended. If it be asked, why there is a greater vascularity or an ap- pearance of blood-vessels passing through the sutures? it is perfectly consistent with this opinion to answer, that the in- crease of blood goes to this secretory organ, for the purpose of the extension of the bones. The explanation here offered accounts also for the general obliteration of the sutures after a certain period of life ; for, the bones having then arrived at their full size, the organ for the secretion of osseous matter is no longer needed; it shrinks and is absorbed, and the bones gradually coalesce ; by which a further advantage is derived, that of an accession of strength to the cranium at large. i Tf any additional argument be necessary in support of this opinion, I may also notice the striking analogy which sub- sists between the separation of one bone of the skull from another by a suture, and that separation which exists be- ad fonticulos, ut aiunt, hze linea notabili latitudine, observatur. Ossibus enim capitis hic locorum cerebro crescente, placide quasi diductis, cartilago augetur, latior evasura, nisi pristina pars simu! in os mutaretur, inde ossa calvariz, eodem modo, quo ossa longa diductis epiphysibus, vel quod unum idemque est, marginibus crescere, liquet, etsi in ossibus, longis sutara epi- physes inter et diaphysin non crispetur. “ Quo junior igitur infans, eo minus crispa et implexa sutura, vel, ut rectius loquar, linea cartilaginosa angusta, ossajungens,observatur. Quum vero aucta wtate ossa, crescente cerebro, diducuntur, eorumque crassitudo, adposita cum interna tum extern potissimum tabulz, (interne enim incrementum citius absolutum videtur) massa ossea, augetur, non potest non esse, quin hee crispa suture forma, quum quidem nasci ceepit, externa in superficie tamdiu, augea- tur, donec tandem ipsa.ea quam maxime impediat, quo minus cerebrum cal- variamvulterius diducere possit, quod pubertatis tempore accidit. Rarissime hee ossificatio ad xtatem virilem usque detinetur.”—Soemmerring De corporis humani fabrica, pag. 212. R3 tween 262 Existence of Phosphate of Magnesia in Bones. tween the body of a cylindrical bone and its epiphysis. They each remain only for a certain Jength of time ; each allows the interposition of a secretory organ; and both begin to be obliterated, when the bones with which they are connected have completed their growth, and their continuance is no longer necessary, L. On the Exisience of Phosphate of Magnesia in Bones. By M. Fourcroy*. eae discovery of a new earthy phosphate in the bones of animals, is a fact in the history of the physical sciences im- portant enough to deserve a place in every journal calculat- ed to promote improvements in natural history. This dis- covery has been made these two years by M. Vauquelin, and myself, in the course of a very extensive inquiry under- taken upon animal concretions, and of which we have from time to time given an account to the public, Having discovered, Ist, the ammoniacal magnesian phos- phate among the materials of the calculi m the human bladder, and among the intestine bezoars of animals ; and 2dly, the phosphate of magnesia in human urine, and the property which characterizes it, in this liquid, of passing to the state of a triple salt very crystallizable, at the moment that the urine becomes ammoniacal by its spontaneous de- composition 3 it appeared to us important to inquire if this magnesian salt, unknown in animal matters until our in- quiries, was not to be found in some animal organs ; and we began our inquiries upon bones, the analogy of which with the urinary receptacles is so well known by physiologists. The analysis of these organs seemed to be brought to pertec- tion; and yet the new experiments to which we submitted the substance under examination, enabled us to discover this salt by methods and processes much more complicated than, those which have been hitherto employed in this species of analysis. * From Annales du Muséum d'Histoire Naturelle, vol. vi. In Existence of Phosphate of Magnesia in Bones, 263 - In order to procure the magnesian phosphate in an osseous ‘pase, the bones of oxen, after being calcined white and well pulverized, must be treated with an equal quantity of sul- phuric acid ; after being allowed to rest five or six days the mixture is diluted, at first with ten times and afterwards with five times its weight of water. The liquor is drained every time 5 ammonia in excess is poured inte all the liquors mixed together; and as these liquors, which were formerly supposed to be the phosphoric acid, contain phosphate of lime and phosphate of magnesia dissolved in the phosphoric acid, in proportion as the ammonia saturates the acid, a mix- ture of calcareous phosphate and ammoniacal magnesian phosphate is precipitated. This precipitate when washed with a little cold distilled water is treated with a ley of pure potash, by boiling them together until no more ammonia is disengaged. The ammoniacal magnesian phosphate is decomposed by this process. The ammonia volatilizes, the phosphoric acid unites itself to the potash, and the salt resulting from it remains in solution; the free magnesia de- posits itself in powder, and mixes with the phosphate of ime at the bottom of the liquor. The latter is now drawn off clear, the precipitate is washed, and beiling distilled vine- gar 1s poured upon it, which dissolves the magnesia without touching the calcareous phosphate 5 the magnesian acetate is decomposed by carbonate of soda, and we have the car- bonate of magnesia, which is dried, of which the weight 1s determined, and which is dissolved in the sulphuric acid in order to obtain it in the state of sulphate of magnesia, the form under which it is more generally and more certainly re- coguised. By repeating this precess a great number of times, in the first place to ascertain the discovery of the phosphate of magnesia in the bones of animals, and secondly to appre- ciate the proportion of it, we ascertained that the acetic acid always dissolves a little lime with the magnesia, and that this Jime could not procced from any thing else than the decom- position of a small portion of the calcareous phosphate by means of potash: thus, in spite of the laws of affinities hitherto determined, it appeared evident that potash sepa- R4 rates 264 Existence of Phosphate of Magnesia in Bones. rates the lime of the phosphoric acid ; but it only separates a very small quantity from it, and only when potash is em- ployed by itself in a great quantity, while lime takes the pot= ash from the phosphoric acid entirely and completely. We have here the effect of the power of masses, called in by Berthollet in order to explain some apparent anomalies in the action of the elective attractions. Ox bones calcined contain about a 40th part of phosphate of magnesia. © Those of horses and sheep yielded a 36th part. Those of the feathered creation, about a 40th part. We were not able to extract, from any of the above, 2 quantity any thing equal to that contained in human bones, We have to remark on this occasion, that ox bones, which we had most frequently and most exactly analysed, appeared to contain the following materials : PHONIC) LOLAATING soi 0. a8 wre ts's fapays'» 51°0 Pbospiate OL Ime sos ensane O26 tarbonate. of lime... .cecsscoces 100 Phosphate of magnesia ........ 1°3 | The phosphate of magnesia existing in animals manifestly arises from their food. Not only have we found this salt in wheat, barley, oats, and vetches, but we discovered it in all the grasses named by Linnzus cerealia, in the proportion of a centieme and a half of their weight ; which is almost double the quantity of the phosphate of lime which they contain. Without doubt, some relation subsists between this fact and those concretions found in the intestines of ani- mals, which are formed of ammoniacal magnesian phos- phate. Tt is not impossible to conceive why human bones do not contain phosphate of magnesia, although this salt exists more abundantly than the phosphate of lime in flour, &c, It appears that it is evacuated by those urines in which we have discovered it, while it does not exist in the urine of such animals as throw it off by the skin or the intestines, Without pushing too far the influence of chemical dis- coveries upon the animal ceconomy, made by the analysis of 3 yarlous Notices respecting New Books. 265 various substances, we cannot pass over, in each of these discoveries, immediate applications, which ought no longer to be neglected. Physiology must necessarily derive great advantages from attending properly to such results. LI. Notices respecting New Books. A Treatise of Mechanics, Theoretical, Practical, and De- scriptwe. By Otrnruus Grecory, of the Royal Mi- litary Academy, Woolwich. 2 Vols. 8vo, and a Volume of Plates. Published by Kearsley. Ir is with much satisfaction we announce the publication of a work of this nature, which has been long wanted. The first volume is devoted chiefly to theory; the second is practical and descriptive. The theoretical part is divided into five books, and these are subdivided into chapters, as the nature of the several subjects seemed to require. Book I. is appropriated to the subject of statics, and is subdivided into six chapters. It commences, as indeed do all the books, with definitions and preliminary remarks; which are succeeded by a statement and illustration of the Newtonian laws of motion and rest, which are assumed as fundamental principles to guide the subsequent inquiries. - The nature of statical equilibrium, with the composition and resolution of forces, are then discussed; forces being con- sidered, 1. as disposed in one plane, and concurring in the same point: 2. as directed to one point, but not confined to one plane: 3, as situated in one plane, but applied to diffe- rent points of a body: 4. as not confined to one plane, and directed to various points of a body, The remaining chapters in this book treat of the centre of gravity, and the centro- barye method ;.the simple machines, or, as they are usually called, the mechanical powers; the strength and stress of timber and other materials; and the equilibrium, tension, and pressure of cords, arches, and domes. The minuter topics connected with these general points of inquiry can- not well be specified here. The 266 Notices respecting New Books. The second book relates to dynamics. It comprehends six chapters; treating of motion, uniform and variable; the descent and ascent of heavy bodies in vertical lines; the motion of projectiles, with observations on ricochet-firing ; descents along inclined planes and curves; the vibrations of pendulums, and the curve of swiftest descent ; central forces ; the rotation of bodies about fixed axes, and in free space, with theorems relative to the centres of oscillation, gyration, percussion, spontaneous rotation, &c.; the physico-mathe- matical theory of percussion, nearly as first delivered in Don George Juan’s Examen Maritimo; and the motion of ma- chines, and their maximum effects; closing with some re- marks showing in what points of view machines ought te be considered by those who would labour beneficially for their improvement. Book III. is devoted to the subiect of hydrostatics. It is divided to four chapters,—on the pressure of non-elastic fluids ; the determination of the specific gravities of solid and fluid bodies ; the construction of hydrometers or areo- meters ; the equilibrium, stability, and oscillations of float- _- ing Wilties: with a particular reference to ships and canal boats and on the phenomena of attraction in capillary tubes. This book contains an extensive and correct table of specific gravities. In the fourth book are given some of the most useful propo- sitions and theorems relative to hydrodynamics. It comprises four chapters. 1. On the discharge of fluids through aper- tures in the bottom and sides of vessels, and on spouting fluids: 2. An account of experiments made by different phi- losophers (as Bossut, Venturi, Eytelwein, Young, Vince, &c.) on the discharge of water through apertures and tubes; and the practical deductions from those experiments: 3. On the effect of water upon the motion of water-wheels: 4. An account of Mr. Smeaton’s experiments on water-wheels. The fifth book, which terminates the first volume, is,on pneumatics, and contains six chapters. The subjects stated and discussed in this book are, the equilibrium of elastic fluids ; the measurement of altitudes with the barometer and thermometer; the motion of air when the equilibrium of pressure Notices respecting New Books. 267 pressure is removed; the theory of air-pumps, and pumps for raising water; the resistance of fluids to bodies moving in them; and results of experiments on the resistance of fluids. The second volume of this work, which, as before men- tioned, is chiefly practical, commences with an introduc- tion occupying about eighty pages, and comprising general remarks, rules, and directions,—on the construction and. simplification of machinery; on rotatory, rectilinear, and reciprocating motions; on bevel-geer, and proportioning the number of teeth; on friction and the rigidity of cords, with the experiments of Vince, Coulomb, &c., and an ex- ample of the power of the capstan, allowing for friction and the stiffness of cords; on water and wind as movers of ma- chinery, with Smeaton’s rules relative to windmills ; on the strength of fired gunpowder; on steam as a mover of ma- chinery, with the theorems and results of Bettancourt and Dalton; and on the strength of men and horses, according to the best and most accurate observations. The remaining part of this volume is appropriated to the description of a variety of mechanical contrivances, in number exceeding an hundred and fifty. These are arranged alphabetically, that they may be consulted with most convenience ; and several of them relate to machines and instruments which have never before been publicly described. In the exposition of the theory the author has generally proceeded by a series of connected propositions and depen- dent corollaries ; those in each chapter having a manifest re- lation to each other, and flowing naturally from the same source. He has avoided the two extremes,—a fatiguing prolixity of detail, which leaves nothing to be filled up by the ingenuity of the pupil, and that obscurity which often results from the suppression of intermediate ideas. Mr. Gregory has not attempted to explain the mature of gravity, impulse, or the other sources of the motion of bodies; and the reasons he assigns in his preface are perfectly satisfac- tory. The general definition of the term force, in a mecha- nical sense, supersedes the necessity of inquiring into the essence of the various kinds of forces which may operate upon 268 Notices-respecting New Books. upon matter. Those who carefully contemplate the process of that gradual refinement of lenguage, which results from the necessary demands occasioned by the progress of civili- sation, will see how requisite it is to appropriate terms ori- ginally of alaxer or of a grosser signification, to some pe- culiar modification of thought ; and hence, that such words as power and force, primarily used to denote animal energy, are now, by a natural extension, grounded upon an obvious analogy, employed to express efficiency im general. In the philosophical acceptation, then, he defines force or power to be that, whatever it be, “* which causes achange in the state of a body, whether that state be rest or motion: and this definition does not require entering into any metaphysical disquisitions relative to the nature of causes, or the connec= tion of cause and effect: that every effect is brought about by some cause, or something which precedes in the order of occurrence, is a truth which none will be disposed to deny ; but what is the agency, or where it actually resides, we can seldom know, except, perhaps, in the case of our own vo- luntary actions. It is not, then, the business of the mecha- nist, strictly speaking, to inquire into the modus operandi : we learn, from universal experience, that the muscular energy of animals, the operation of gravity, electricity, pressure, im- pact, &c. are sources of motion,or of modifications of motion ; and hence, without pretending to know the essence of either of these, we do not hesitate to call them mechanical forces ; because it is incontrovertible that bodies exposed to the free action of either, are put ito motion, or have the state of their motion changed. Forces, therefore, being known to us only by their effects, can only be measured by the effects they produce in like circumstances, whether those effects be creating, accelerating, retarding, deflecting, or preventing motions: and it is by comparing these effects, or by referring them to some common measure of ready appreciation, not by ascertaining the essential nature of any forces, that me- chanics is made one of the mathematical sciences. ‘© Besides, what is meant by the nature of any thing? As we are ignorant of its essence, or what makes it that thing and no other thing, we must content ourselves with the dis- covery a Notices respecting New Books. 269 covery of its qualities or properties ; and it is the assemblage of these which is commonly called its nature: yet this is very inaccurate, since these are only the consequences of the essence. Hence we can give no definition of even the simplest of things which comprehends its real essence.” We have no hesitation in saying that this work cannot fail to prove extremely useful. The first volume, in parti- cular, is executed in a manner highly creditable to the judg- meut and abilities of the author, who has rendered an essen- tial service to his country by its publication. In praising inthis particular manner the merits of the first, we would not be understood as meaning to censure the second vo- lume: from the very nature of its contents it was impossi- ble to infuse into it the mind which pervades the other; but the author has collected in it much useful information, which with less industry and judgment than he possesses could not have been brought together in the same compass. A future edition would probably be rendered still more valuable, by the suppression or alteration of a seemingly ex parte state- ment of the comparative merits of Mr. Watt’s steam-engine and that of Mr. Hornblower; which however is not given in the work as the author’s own production, but as from Mr. Hornblower, or some relative of the same name. Should the work meet with that reception which it merits from the public, we have no doubt but a new edition will soon be demanded. ‘ oma A Treatise on the Teeth of Wheels, Pinions, €¥c., demon= strating the Lest Forms which can le given to them for the various Purposes of Machinery, such as Mill-work, Clock-work, &§c.; and the Art of finding their Numbers. Translated from the French of M. Camus; with Addi- tions. Illustrated with fifteen Plates. Published ly J. Taylor, Holborn. This work is a translation of the tenth and eleventh books of M. Camus’s Cours de Mathematique. The abi- lities of the author are so well known to the learned world, that nothing that can be said here can add to his fame; and it is but justice to the translator to say, he has executed his part 270 Notices respecting New Books. part with fidelity, and in a way creditable to himself. ft is of much more importance than mere operative mechanics can possibly conceive, that the best form of the teeth of wheels should be ascertained on true mathematical princi- ples. Where this is not attended to, there will always be an unnecessary load on the machinery, arising from mere fric- tion, a consequent waste of power and time, and a propor- tionate expenditure for repairs. We cannot however avoid noticing that there is a manifest disagreement between the text of this work, and an illustration of the application of the epicycloid to the teeth of whecls given in the preface. The latter directs the epicycloid curve to be generated from the primitive diameters of the wheels that are to work into each other; the former directs them to be generated from circles equal to radius only of these diameters.—This work, we doubt not, will be found very useful, and we hope will procure to the publisher a proper return for the service he has rendered to the public by presenting it in an English dress. The Vaccine Contest; or ‘* Mild Humanity, Reason, Reli« gion, and Truth, against fierce unfeeling Ferocity, over- bearing Influence, mortified Pride, false Faith, and De- speration,” ic. By WiiiiaM Brarr, M. A. Surgeon of the Lock Hospital, &c. &c. Published by Murray. In this work, designed for the use of clergymen, heads of families, and other unprofessional readers, Mr. Blair at- tempts to answer the objectors against the cow-pox, on quite a new plan; viz. by quoting their own words, and making them refute themselves; in which it is but justice to say, he has effectually succeeded. This popular work is a very fair exposure of the unprincipled means to which the anti-vaccinators have resorted to turn the prejudices of the ignorant into a source of dishonest emolument to them- selves. Doctor Patterson, of Londonderry, strongly impressed with the importance of the subject, is engaged in * Re- _ searches concerning Pestilential and. Epidemic Diseases, 4 with | \ Royal Society of London. 271 with a View to obtain valid Principles whereon to foand a Civil Constitution of Medical Police for Ireland.” To every one conversant in this field of inquiry, it is manifest, that the climate of the country, the physical and moral attributes of the inhabitants, their political and com- mercial relations, their ceconomical institutes, and other corresponding circumstances, must be taken into considera- tion in a work of this description. It will also he necessary to take a retrospective survey of the numerous malignant and reigning distempers which have prevailed in many parts of the earth throughout a series of ages. These are not easy tasks—they are not small undertakings: yet, dificult and extensive as they are, little short of their achievement will answer the purpose; a purpose which has in contemplation objects of the first national importance. Mr. Rudge has just published the Fourth Fasciculus, which completes the First Volume, of his Descriptions and Figures of the Rare Plants of Guiana. The plants described in this work formed a part of that superb collection of natural history consigned from Cayenne to the National Museum at Paris: they were five years col- lecting in Guiana, by order of the French government, and were captured on their passage by two British privateers at the commencement of the present war. We understand that only 150 copies of this work will be published. LII. Proceedings of Learned Societies. ROYAL SOCIETY OF LONDON. Wises 27. The Right Honourable President in the chair. —The reading of an interesting paper, consisting of observa- tions on the marine barometer and thermometer, made by captain Flinders, on the coast of New Holland, in the years 1801, 1802, and 1803, commeneed, and the society ad- journed, in consequence of the Easter holidays, till the 17th of April. The President in the chair.—Continuation of d72 Royal Society of London. of the above paper, containing a great variety of isolated facts of the most extraordinary and unaccountable fluctua- tions or stagnations of the mercury in the barometer and thermometer. On that evening Messrs. Lacépéde and Cuvier, of Paris ; M. Prevot, of Geneva; and Mr. Charles Harding, of Bre- men, the discoverer of the new planet Juno, were elected fellows of the Royal Society of London, in the foreign list. April 24. The President in the chair.—Continuation of captain Flinders’s meteorological reflections, in which the author seemed to believe that he had accumulated sufficient data to enable him, with a seaman’s experience, to prognos- ticate truly the general state of the weather, and the approach. or continuance of a storm, by the assistance of his barometric ebservations. This desideratum is doubtless within the sphere of human science, and might be attained by atten- tion and industry, only in the course of a few years, if every captain of a vessel would bestow on it the same attention as captain Flinders, and communicate his observations with equal promptness. The number, talents, and opportunities of our naval officers render it extraordinary that they have not before this time collected such a multitude of facts as the philosopher in his cabinet could arrange and digest into a practical system, that would enable the navigator to anti- cipate the direction and strength of the wind in every lati- tude, and at all seasons of the year. There exists, indeed, at the present moment, a great deal of meteorologicalknowledge, among individuals of our seamen, unknown to many of our meteorologists, and equally unprofitable to the public, merely from diffidence in the observers to write down their observa- tious. It may not be improper to add here a peculiarity of the marine atmosphere, not observed by this minute narrator of facts, nor perhaps by any other seaman, namely, that the air or wind always traverses the sea in distinct masses or bodies, and in parallel lines. It is a fact, to which there are few exceptions, that a current of air, whatever may be its direction or velocity, uniformly travels in a right line at sea, till it is either entirely absorbed or its power cxhausted by Royal Society of London. 273 by rarefaction. The reverse is the case on land ; as no cur- rent of wind can pass many miles without experiencing a change of temperature, density, velocity, and even direc- tion, in consequence of the variegated surface and tempe- rature of the earth. The rencounter of two opposite cur- rents of wind, at sea, does not produce the effect proper to solid bodies in motion, according to the received laws of mechanics; on the contrary, as their temperatures and den- sities must necessarily be different, each pursues its unde- viating course without any change, excepting only that the least dense is obliged to ascend and make room for the other, which keeps next to the surface of the water; notwithstanding which, each proceeds with nearly its original velocity. Two currents of air, whatever may be their temperatures or den- sities, never incorporate either by sca or land, without the intervention of a third body (such as mountains, &c.), which destroys their respective velocities. No such resisting bodies being at sea, the different currents of wind must consequently follow the law of their densities. Parallel currents often " eccur in, very short distances, and the intervening spaces frequently experience dead calms, sometimes accompanied with fogs, or with unclouded brightness, and considerable . heat. This circumstance will, on many occasions, account either for the stagnancy or rapid fluctuation of the mercury in the barometer at sea; which can never happen, even in the warmest or most electrical climates, on shore, where there is a much greater and more general sameness of density and temperature in the atmospherical currents, in consequence of the greater facilities of commixtion, and often, indeed, of chemical union of the different gases. For these remarks, which form no part of captain Flin- ders’s communication, we are indebted to a gentleman who has made a number of observations on this important sub- ject. Should any of our nautical-readers, or others who may have had an opportunity of making similar observa- tions, communicate to us the result of their experience *; we shall gladly lend our aid to the collecting of such facts » * Addressed to the Editor of The Philosophical Magazine. Vol. 24. No. 95. Apriliso6. S$ as 74 London Instiluzion. as may tend io the elucidation of this subject; by giving them a place in our work. A letter from Smithson Tennant, esq. to the President; Was read, announcing his discovery of native minium in 2 vein of galena in Devonshire. A small quantity of this Wative minium was found in the centre of a piece of cubic galena, accompanied with crystals of spar. This ingenious chemist promises to forward specimens of the mineral to his mineralogical friends, for their personal inspection. LONDON INSTITUTION. A general meeting of the proprietors of this fstitution was held on the o4th of April, at its house in the Old Jewry, to receive a report from the managers on a royal charter pro posed to be applied for, to obtain for the society the rights of a corporate body. A draft of the proposed charter was read to the meeting, which, after some discussion, was ordered to be printed for the use of the proprietors, and to be taken into their consi- deration at a future meeting. The meeting then proceeded to elect, by ballot, the first officers, &c. of the institation, preparatory to the insertion oftheir names in the proposed charter ; when the following gentlemen were elected : President—For One Year. Sir Francis Baring, bart. M. P. Vice- Presidents For Four Years. Sir Richard Neave, bart. F.R.S. and F. AS. . For Three Years. rt Beeston Long, esq. . For Two Years. , George Hibbert, esq. F.LS. For one Year. John Julius Angerstein, esq. Managers—For Pour Years. ~ Richard Clark, esq. F.A.S. chamberlain. Rev. Matthew Raine, D.D. F.R.S, and F.A.S; > Richard Sharp, Esq. F.A.S. | John Smith, esq. M.P. Henry Thornton, esq. M.P. London Institution. O75 For Three Years. Jeremiah Harman, esq. Benjamin Harrison, esq. F.A.S, William Hasledine Pepys, esq. John Rennie, esq. F.R.S. F.A.S. Robert Wigtam, esq. F.R.S. FLAS. | For Two Years. Thomas Bodley, esq. Charles Bosanquet, esq. John Petcr Hankey, esq. Joseph Huddart, esq. F.R.S. Job Matthew Raikes, esq. For One Year. Thomas Baring, ‘esq. Samuel Boddington, esq. Nathaniel Bogle French, esq. William Henry Hoare, esq. Abraham Wilday Robarts, esq. Visitors—For Four Years. Sir John William Anderson, bart. M.P. Henry Hoare, esq. F.A.S. William Saunders, M.D. F.R.S. F.A.S. For Three Years. Sir William Blizard, F.R.S. F.A.S. Sir Charles Price, bart. M.P. __ Right hon. the lord mayor, James Shaw, esq. For Two Years. Thomson Bonar, esq. Harvey Christian Combe, esq. M.P. Sir Hugh Inglis, bart. M.P. Fer One Year. Charles Grant, esq. M.P. Robert Hankey, esq. William Manning, esq. M.P. Auditors—For one Year. Isaac Lyon Goldsmid, esq. Thomas Hughan, esq. S2 John 276 Royal College of Surgeons.--Soctety of Antiquar ies. John Inglis, esq. Thomas Reid, esq. William Salte, esq. Treasurerv——For one Year. Sir Willam Curtis, bart. M.P. Secretary—For one Year. Samuel Woods, esq. ROYAL COLLEGE OF SURGEONS, LONDON. At the meeting. of this body held on the 16th of Apnif (instant), the Jacksonian prize for 1805 was adjudged to John Hyslop, esq. of Fenchurch-strect, surgeon, for the best dissertation on ‘ Injuries of the head from external vio- lence.” There are two prize subjects for the present year: 1. The diseases of the joints, particularly the hip and knee, and the best mode of treatment. 2. Hernize, and the best made of treatment. The dissertations are required to be delivered in before Christmas 1806. SOCIETY OF ANTIQUARIES. March 27. ‘The right hom. the earl of Leicester, presi- dent, in the chair. An old painting was exhibited of three real portraits, placed around a table covered with cards and “money, which was marked Edward VI. and Elizabeth : the three old gentlemen seem deeply engaged at play, and from their dress and character it was conjectured that the painting must have been executed shortly after the days of Elizabeth. The learned president scemed to have the most correct notions of the characters supposed to be delineated. Drawings of some more of Mr. Weston’s Greek coins were also exhivited. April17. The president in the chair.—Mr. Gough exhi- bited some excellent drawings of the church of St. Albans, displaying almost every style of architecture that has been used in this country. A letter to the president from Mr. Morris at the Cape of Good Hope was read, contajning accounts of the different English Society of Antiquaries. 277 English inscriptions found on stones there, relating the ar- rival and departure of sir-IJenry Middleton’s fleet of East India merchantmen in 1604 and 1609, being the fourth voyage to India. The inscriptions were on stones placed in @ conspicuous part of the shore, and designed merely as a notice for other English ships that might touch there, where and when any others might probably pass. ‘The same writer mentions, that he saw the flake of an anchor on the sum- mit of ‘Table mountain, a height at which no human effort could likely have placed it. The right hon. lord Hutchinson was elected a fellow of this society, which was adjourned till the anniversary on the 23d of Apzil. On the 28d of April, being St. George’s day, the society of antiquaries met at their apartments in Somerset-place, in pursuance of their statutes and charter of incorporation, to elect a president, council, and officers of the society for the year ensuing :—whereupon George, earl of Leicester, Craven Grd, esq. William Bray, esq. John, lord bishop ef Salis- Rev. John Brand, A.M. bury, Sir H.C. Englefield, bart. John Willett Willett, esq. Rev. Dr. Hamilton, Joseph Windham, esq. and Samuel Lysons, esq. Rev. T. Wm. Wrighte, A.M. eleven of the council, were rechosen of the new conncil 5 and Edward Astle, esq. John Wilkinson, M.D. James Bindley, esq. Henry Norton Willis, esq. Francis Douce, esq. Hon. Brownlow, lord bishop Charles, duke of Norfolk, of Winchester, and Hon. John Peachy, Chas. Wat. Williams Wynne, John Sylvester, esq. esq. ten of the other members of the society, were chosen of the new council, and they were severally declared to be the council for the year ensuing; and on a report made of the officers of the Society, it appeared that ' George, earl of Leicester, was elected president, William Bray, esq. treasurer, Samuel Lysons, esq. director, $3 Rev. 378 French National Institute, Se. Rev. Thomas William Wriglhite, A.M. secretary, and Rey. John Brand, A.M. secretary for the year ensuing. The society afterwards dined together at the Crown and, Anchor tavern in the Strand, according to annual custom. FRENCH NATIONAL INSTITUTE. __ The class of history and of antient literature of the F beach. National Institute lately held a meeting for the purpose of distributing the annual prizes. One of the subjects which had been proposed was the fol- lowing : “To examine what was the administration of Egypt, from the conquest of that country by Augnsias to the taking of Alexandria by the Arabs; to give an account ‘of the changes which it experienced during that interval; the con- dition of the Egyptians ; and to explain what was the con- dition of strangers domiciliated in Egypt, and particularly the Jews.” Of all the memoirs sent to the meeting, not one appeared, to possess sufficient merit to obtain the prize; the subject was therefore again given out for the meeting in the month of July 1807. The class then proposed, as the subject of a prize essay to be adjudged in July 1808, ‘ to examine what has been the influence of the crusades upon the civil liberty of the people of Europe, upon their civilization, and upon the progress of, their learning, commerce, and industry.” . The prize offered 1s a gold medat of 1500 franes in value $ _ and the discourse, which must be in French or Latin, must be given in before the Ist of April 1808. IMPERIAL ACADEMY OF SCIENCES, LIFERATURE, AND. THE FINE ARTS, TURIN. This ‘academy, formerly the Royal Academy of Turing, which was new modelled in consequence of Piedmont being annexed to France, has published. two quarto volumes i memoirs for the years 12 and 13. One of the volumes is, appropriated to the labours of the Class of Literature and the Fine Arts; the other, compiled by the secretary, M. Vassali Eandi, mentions the changes that have taken place in the list of academicians, the various papers read at the meetings, and Imperial Academy of Turin. 279 and the presents made to the academy. After this follows an account of the labours of the academy up to 1805, which occupies 250 pages, and then the dificrent memoirs, viz. 1. Description of a new portable barometer for measuring heights and depths, with observations made with it in the circles of Turin and Saluzzo; by Vassali Eandi. 2. Account of a waterspout that occurred in the territory of Revel, in the circle of Saluzzo, March 27, 1798; with remarks on the cause of the phenomenon : by the same. 3. On the different capacities for conducting heat, ascer- tained, by experiment, in different articles used for clothing: by J. Sennebier. 4. Of a new species of hawkweed (crepis), to which are added some eryptogamiz of Piedmont: by J. Baptist Balbis, A figure of this plant, which Mr, B. calls crepis ambigua, is given. Among the cryptogamiz are the following new species : mucor flosculentus, pexixa amentacea, lichen nivalis, These likewise are figured. 5. Experiments on the effects of the nitric and oxygenated, muriatic acid, employed topically in the treatment of various diseases: by M. Rossi. Mr. R. gives an account of the cure of several gangrenous ulcers, venereal buboes, and even contagious carbuncles, effected by the application of these acids. 6. Meteorological observations made durimg the solar eclipse ‘on. the 30th of January 1805, at the observatory of Turin ; with reflections on them: by Ant. Mar, Vassali Eandi. 7. On a specics of cassia, that may be substituted for: the senna of the shops: by M. Bellardi. This is the cassia ma- vilandica, which Mr. B, would call suecedanea, because, ac- cording to him, it may supply the place of cassia lanceolata, 8. Inquiries into the nature of the Galyanie¢ fluid: by A.M. Vassali Eandi, 9. On the mines of plumbago in the departments of the Sture and Pa: by M. Bonvoisin. 10, Attempts to improve nut oil: by the same. Mr. B, points out a method of purifying this oil, and rendering it as fit for lamps as other fine oils, $4 J}, Exa- 280 Imperial Academy of Turin. 11. Examination of the action of the Galvanic fluid on different gases: by J. A. Giobert. 12. An anatomical and physiological essay on the lymph- atic glands: by professor Rossi. 13. Solution of a problem depending on the theory of permutations and combinations: by professor Balbo. 14. Explanation of the circumstance of a fish being occa- sionally found with prickles in the river of the 27th military division: by M. Giorna. This fish is the cyprinus idus ; the male only has prickles, und loses them after spawning- time. 15. A chemico-medical essay on the pulmonary consump- tion, by Jos. Hyac. Rizzetti.. The principal subject of this essay is the nature of the matter expectorated. The following papers are by foreign members : 1. Memoir on the use of varying the coustant quantity in summing up equations with variable cocflicients, by Dr. Brunacci, 2. A systematical enumeration of the coleoptera found in the territory of Saluzzo, with observations by Lau. Ponza, To this catalogue are annexed two plates, containing the fo}- lowing new species. Coccinella numeralis,—c. obsoleta,— curculio spinosus,—c.dulius,—c.rugosus,—cerambyx preus- tus,—c. melanocephalus,—chrysomela melanocephala,—ch, variegata,—ch.pretiosa,—ch.luctuosa,—scaraleus rufescens, —cantharis impressifrons,—atielabus funereus,—dytiscus silphoides,—tencbriorufus,—lirrhus Rossii,—carabus attenua= tus,—c.metallicus,—c, Rossii,=—forficula bipunctata,—silpha sinuata,—s, scabra. 3. On the motion of the hairs of the hypnum adiantoides, by Palamedas de Suffren. Parts endued with irritability had already been observed in the hairs of some mosses. Mr. De S. has found it inthose of the hyp. diant. aud describes all the singularities of the phenomenon. This paper is ac- companied with a plate. 4, Of a resin employed by the bee in constructing its combs. By Fr. Mouxy Deloche. 5. Entomological observations; by Mr. Disderi. Mr. D. . first 3 Academy of Genoa.—Viccine-Pock Society, Fc. 281 first sketches the history of the silkworm; and then pro- ceeds to certain hymenoptera, chiefly of the genera ten- thredo, ichneumon, sphex, and vespa. 6. Specimen of the fungi of the vale of Pisa, by Hugh Camino. The new species are figured on three plates. They are Agaricus elatior: a. miniatus: a, pezizoides: a. atrosanguineus: a. tricolor; Boletus scobinaceus: Hel- vella grandis: h. reflexa: h. inflata: Peziza ochracea: p. pyriformis: Reticularia rosea: Mucor fruticulosus. 7. Observations on the native gold found among sand, by Lew. Bossi, of Milan. ACADEMY OF GENOA. On the 26th of January last this academy had a public meeting, which was attended by the chancellor of the ex- chequer Le Brun, member of the French National Institute, and other distinguished inhabitants. M. Cotardo Solari opened the meeting with a discourse on the following sub- ject: ** That learning, when not regulated by wisdom, is productive of more injury than benefit to a state.” The fol- lowing prize questions were afterwards announced : 1. Has any other of the heavenly bodies, besides the sun and moon, any influence upon the meteorological appear- ances of the world ? 2. Which is the best method of rendering the harbour of Genoa more secure and convenient for shipping ? 3. Whether is it more advantageous for the inhabitants of the Ligurian republic to encourage the wine or oil trade? and what is the best method of cultivating the vine, and the plants which produce oil? The prize for the best answer to each of these questions is a gold medal of 400 ducats in value: the second best dis- course will be rewarded with a silver medal. The discourses ynust be given in on or before the 15th of November next. VACCINE-POCK SOCIETY, AMSTERDAM. This society lately held its annual sitting; when it ap- peared that out of 1800 persons inoculated with the cow pock during the years 1804 and 5, not onc had died, or taken the small-pox, MEDICAL 282 Medical Society of Lyons, &c.—Aérostation. MEDICAL SOCIETY OF LYONS. This society has announced the following prize question : «* What are the diagnostic and prognostic signs afforded by the state of the tongue, the lips, and the teeth, in acute and chronic disorders ? and what advantages may result to prac- tice from this discovery ?”—The prize is a gold medal of 300 francs in.value. The answer must he given in on or before August 1807- fECONOMICAL SOCIETY OF FHE BAHAMA ISLANDS. This society has been presented by the British government with a hundred acres of ground ‘near Nassau in New Provi- dence, for the purpose of founding a botanical garden, and erecting a house wherein the society is to hold its mectings. -AMERICAN SOCIETIES. Since Louisiana was added to the United States of North. America, two learned societies have been formed in that di- strict, at New Orleans and Natchez. That of the former is ealled “* The Literary Society,” and publishes a monthly journal, particularly tatended to extend a knowledge of the country to other nations, and containing a collection of useful learning. - The literary society at Natchez was estas blished in Oct. 1803, and is called ‘* The Missisippi Society for the Discovery and Extension of useful Knowledge ;’’ it consists of between 30 and 40 members, has correspondents in the several united states, and special regulations of its, own: both the above societies are sanctioned by the Ame~- rican government, LI. Intelligence and Miscellaneous Articles. AEROST ATION. Lisle, April 9. Tus ninth aérial ascension announced by M. Mosment took place last Monday, (the 7th inst,) in the elegant, rotunda of the circus of this city, in presence of an immense crowd of spectators. From day-break the aéronaut was busily occupi- i Pi ed Tcelani. 283 ed in the production of hydrogen gas; the sky was serene, and at mid-day the operation of filling the balloon was com- pleted and every thing ready. M. Mosment Jeapt into, the car ; and upon a signal being given the balloon was set at li- berty, and ascended very rapidly into the air, amidst the shouts of the spectators. M. Mosment repeatedly waved his flag as he ascended, which was adorned with the impenal eagle. The wind was northerly, and the balloon was car- ried gently before it. At a certain height the aéronaut let goa parachute to which an animal was attached, and the experi- ment succeeded admirably. In the mean time the balloon continued to ascend, and appeared as if exactly above the. town. At.one o’clock it seemed to have encountered some adverse winds. Something red was then seen slowly de-. scending, which was picked up, and found to be the flag which the aéronaut carried up with him. This however ex- cited no disagreeable emotions, and all eyes were tarned to, the balloon, which soon ascended to such a height as, to ‘be- come invisible. The crowd then began to disperse, perfectly satisfied with the success of the experiment ; but a rumour yan through. the populace, that the dead body of a man had been found dreadfully mangled in one of the fossés of the town. This excited some inquiry ; and upon inspecting the body, it was found to be that of the unfortunate acéronaut, but so covered with blood that it was with difficulty he was, recognised. } This event gave rise to various conjectures ; but it is ge- nerally supposed that the car was too shallow, and that M. Mosment had fallen asleep, as often happens to aéronauts when in certain regions of the air, and had been shaken out by the violence of the winds. Itis possible also that one of the cords may have slipt, and that M. Mosment losing bis balance had fallen out. The balloon bas not yet been found 5 which prevents the real cause of the accident from being as- certained. ICELAND. « The Danish government is occupied in the amclioration of the lot of the inhabitants of Iceland, a people removed lo the confines of the polar circle, but interesting. on account of 284 New Musical Instrument. — Antiquities, Sc. ef the zeal with which they cultivated the sciences in the 10th and 11th centuries, and on account of the voyages they made to America. Iceland, almost ruined by various physical and political misfortunes, is about to be restored ; a regular city is building, to be called Reyhiavig ; and it is already peopled by colonies of natives as well as strangers ; a free port invites the vessels of commerce ; and a college, where even the an- tient languages and natural history are taught, is im the full exercise of its functions. NEW MUSICAL INSTRUMENT. M. Diez, at Emmerich on the Rhine, has invented anew musical instrument, which he calls a Melodion. It occupies — Jess room than an ordinary piano forte, and may be played on by any common performer, after a little practice. That which distinguishes it above all other instruments of the kind, is thecircumstance of its producing the sounds of the clarionet, hautbois, and bassoon, in the softest piano or the most bril- liant forte movements. The cost of such an instrument is about 40 louis d’ors. ANTIQUITIES. A letter from Petersburgh, of the 19th of March, mentions the discovery of two great cities in the Russian empire, of which no traces can be discovered in history 3 one of them in the Isle of Taman in the Black Sea, the other in a di- strict in Siberia. CHEMICAL AFFINITIES. An intefligent correspondent, Mr. Collard of Birming- ham, the proprietor of a chemical laboratory in that neigh- wourhood, in which many articles necessary to the arts and manufactures of this kingdom are prepared on a very large scale, has communicated to us a new fact well worthy of the attention of chemists. Contrary to the common tables of affinities, he finds that copper may be precipitated from its solution in the sul- pburic acid by tin. All that is necessary to the success of the experiment is, that the solution be nearly at the boiling point, or actually boiling, when the tin is put into it. The tin made use of ought to be in filings or in leaf, or reduced 3 to \ » Mineralogy. 985 to thin fragments by pouring it, when in fusion, into cold water, To the enlightened chemist we need not point out the ex- periments suggested by this new and curious fact, and the important results to which it may ultimately lead. If cop- per and tin, by a mere difference in the temperature of the solution, may be made mutually to precipitate each other, it is not impossible that the order of affinities with respect to other metals for the different acids may also be inverted by circumstances connected with temperature. Should any » such results be obtained, they will be productive of incalcu~ lable advantages in many intricate cases of analysis. The different results obtained in apparently similar experiments, by equally accurate chemists, may perhaps have been owing in some cases to the existence of such a law as we now allude to. MINERALOGY. Dr. Aires, from New Jersey, who has Tately explored se- veral of the western counties of the State of North Carolina, in search of gold, reports, that he has discovered gold in branches and creeks in the counties of Cabarrus, Mont- gomery, and Randolph, in a north and north-east course, and in the county of Mecklenburgh, ina south and south- west direction from the first sound, where none had ever been discovered before, except in three or four branches near Reed’s (the first discovery) in Cabarrus county. A few pieces of gold, intermixed with stone, have been found on the surface of the earth, and some ploughed up in most of the said counties. Several of the said water-courses contain considerable quantities of gold dust, which can be collected by washing the sand, after the first or common washing, with a machine proper for the purpose, and then by mixing mer- cury with the sand thus washed, which will unite with the particles of gold, and form an amalgam, whence the mercury may be driven off by heat. A copper mine has been discovered on the estate of Hans Hamilton, esq., in the county of Dublin, which promiges to be very productive. A company has been formed, and are already engaged in carrying it on. TRAVELS. 286 Travels. —Analysis of Waters—Surgital Instruments. TRAVELS. ' The Polish Prince Alexander Sapieha has concluded his ecological and archeological travels, and has returned to his estates in Poland forthe purpose of enjoying there the treasures of art and science which he has collected. His longest stay was at Athens, where he was so forttinate as to preserve many of the last rays of the declining grandeur of antient Greece, in thcir native splendour. . The embassy to China left Maisnabischin, the first Chi- nese frontier town, in December, for Pekin. it consists of 120 persons; the rest of the suite returns, and some persons arealready arrived in Russia. Six years ago, a Russian caravan, 200,000 rubles in value, going to Taschkent, was plundered by the Kingise. The chiefs have now engaged to make good the loss amicably. The South American Society of Commerce at Petersburg have received intelligence that M. Resanow, the Russian am- bassador to Japan, has not yet been admitted to an audience of the sovereign, but that he has been in other respects. well received; the presents of which he was the bearer having been accepted, and an exchange made of the same de-, scription. ANALYSIS OF WATERS. i Dr. Menuret, of Paris, has lately analysed the different waters in that neighbourhood. The water of the Seine contains 5 grains 42 of foreign matter in each pint. That of the river Yvette yields 7 grains 11; that of the Arceuil, 7 grains 57, ; that of Ville d’Avray, Q grains 3%. Bristol water contains 14 grains 18, &c.” Thus, of all the waters drunk at Paris, that of the Seine is the most salubrious, the purest, and the lightest. SURGICAL INSTRUMENTS. Drs. Faust and Hunold are preparing a work, in which they endeayour to prove, that, with the exception of the lancet used in inoculation, every surgical instrument ought, to be dipped in oil before proceeding to the operation, and should also be heated to the temperature of the blood. By’ - these 4 remarkable Hen.—Lectures, ec. 287 these precautions they contend that the pain of the opera= tion is always diminished. A REMARKABLE HEN. For the three last summers, a hen, the property of Charles Ranken, at Auchinairn, parish of Cadder, has frequently Jaid eggs of an extraordinary size and weight. Within these few weeks, she has laid three eggs, each of which measures in diameter 64 inches by 713, and weighs fully 32 0z.; and generally, on the day before she lays the large egg, she lays ari ege of an ordinary size. LECTURES. Mr. Taunton’s next Cotirse of Lectures on Anatomy, Phy- siology, and Surgery, will commence on Saturday the 24th of May, at 8 o’clock in the evening, at his house in Gre- ville Street, Hatton Garden. LIST OF PATENTS FOR NEW INVENTIONS. To Samuel Miller, of the parish of Saint Pancras, in the county of Middlesex; for various improvements in the working of coal, tin, Iead, and other mines, by which there will be a great saving of fuel and labour, and many accidents prevented. Dated April 1, 1806. To James Keir, of West Bromwich, in the county of Stafford, esq.; for his improved method of manufacturing white lead. Dated April 3, 1806. ; To William Henry Lassalle, of the city of Bristol, apo- thecary ; for certain improvements in soap. Dated April 5, 1806. | To James Kay, of Preston, im the county of Lancaster, machine-maker ; for improvements upon Thomas Johnson’s patent machine for dressing cotton, silk, and other goods by power. Dated April 17, 1806. To Thomas James Plucknett, of the parish of Christ Church, in the county of Surry, agricultural machine ma- ker; fora machine for dibbling and drilling all kinds of grain and pulse. Dated April 17, 1806, METEORO- 288 Days of the Month, March 27 METEOROLOGICAL TABLE, Meteorology. By Mr. Carey, or THE STRAND, For April 1806. Thermometer. |, 8 o’Clock, Morning, SS ee ee i Height of S |the Barom. PA Inches. 42°) 28°85 40 “89 39 soc 38 ‘90 38 | 30°06 34 °30 34 BAA 35 “09 36 ‘10 41 |} 29°95 42 -°90 39 *86 49 “90 40 ies 38 °51 34 *35 290 *65 33 “Gio 34 °58 34 “80 40 | 30°28 45 °40 4g °36 52 on 52 2or 48 *30 45 “18 43 129 46 28 40 25 38 Biol: 3 Degreesof Dry- rl E Weather. 2 Bh 12° |Cloudy 16 |Cloudy g |Cloudy 23 |Cloudy 12 |Cloud 21 {Cloudy 13 |Cloudy 21 |Cloudy 7 |Cloudy 22 {Fair 37. {Fair 34 |Fair 34 |Fair 25 |Fair 14 |Cloudy 20 |Cloudy 22 |Cloudy oO |Snow o |Snow 23 |Cloady 47 {Fair 47 |Fair . 18 |Cloudy 7 |Cloudy 17. ‘|Fair 5 |Cloudy 0 |Showery 30 |Fair 10 ©jCloudy 18 |Cloudy 31 |Cloudy N. B. The barometer’s height is taken at noon. ne [ 289 ] LIV. On Transit Instruments. By Ez. Wavxer, Esq. To Mr. Tilloch. SIR, Astronomers have, in all ages, been very attentive to the construction of instruments for determining the exact time when the sun, or any other celestial luminary, passes over the meridian. The best instrument that has yet been in- vented for this purpose, 1s the transit telescope; but the difficulty of procuring a proper foundation to fix it upon, and the expense of fitting it up, must render its use ex- tremely limited. Clocks and watches may be regulated for occasional observations, by means of equal altitudes of the sum or stars, taken either with’ an astronomical quadrant or a Hadley’s sextant: but these methods are very incon+ venient fur keeping the daily rate of a time-keeper, in con- sequence of the length of the calculations, and the time that is required for taking the observations. Hence it may be presumed, that an instrument for finding the exact time of rioon in an easy manner, is still wanted, to supply the place of the transit telescope. The method used in former ages for resolving this pro-, blem has, .perhaps, been too much neglected since the time that the science of optics began to receive so many improvements. The method to which I allude. is that of finding a meridian line by means of the sun’s rays transmitted through a small cireular aperture made in a piece of metal. In this manner, a kind of transit instru- ment may be constructed, at a small expense, in many situa- tions that afford no foundation for a transit telescope, and to a greater degree of accuracy than may, perhaps, be gene- rally supposed. Having, some years ago, drawn a line by this method, and being desirous to know how far it deviated from the true meridian, [ took 14 equal altitudes of the sun from the surface of a fluid with one of Mr. Stancliffe’s best 12-inch sextants. The time of noon, derived from the mean of Vol. 24. No. 96. May 1806, #9 those 290 _ On Transit’ Instruments. those observations, differed only 2:27” from the time that the sun passed over the meridian line on the same day. But in order to observe the sun’s transit over the meridian with greater precision, I drew two, other lines on each side of the meridian line, which were parallel to it, and at such distances, that the imterval of time taken by one of the limbs of the sun’s image was about 40 seconds in passing from ove line to another, when the sun was near the equator. Those who are at all acquainted with the use of the transit telescope, will be at no loss to comprehend the use of these lines; and those who may want directions for the use of ~ that instrument, may consult a treatise on the method of finding the longitude at sea by time-keepers, written by the Sate Mr. William Wales. To those directions I shall only add, that the room in which the lines are drawn must not be made too dark during the time of observing, as it is ne- cessary to see the lines before they are illuminated by the sun’s image. When the solar rays, that flow through a small circular aperture into a room, are received upon the floor, an ellip- tical image will be formed, consisting of a bright central image, and a penumbra surrounding it. |This penumbra renders the contact of the sun’s image with a line less cer- tain: but, notwithstanding this inconvenience, I am con- vinced that an experienced observer, under favourable cir- cumstances, will generally determine the time of the sun’s, passage over the meridian line to one-fifth of a second, or less, when the distance between the aperture and the sun’s- image on the floor measures about 12 feet. Further parti- culars respecting the construction and use of instruments of this description will be submitted to your inspection at some future opportunity. I am, sir, Your most humble servant, Ez. WALKER, Lynn, May 8, 1806, ‘ LY. Account [291 | LV. Account of a Series of Experiments, showing the Effects of Compression in modifying the Action of Heat. By Sir James Hau, Bart. FR. S. Edin. (Continued from p. 203.] ‘IV. Experiments in Gun- Barrels resumed.—The Vertical _ Apparatus applied to them. —Barrels bored in solid Bars. —Old Sable Iron.—Fusion of the Carbonate of Lime.— Its Action on Porcelain.— Additional Apparatus requir ed in consequence of that Action.—Good Results; in parti- cular, four Experiments illustrating the Theory of In- ternal Calcination, and showing the Efficacy of the Car- bonic Acid as a Flux. Sixce I found that, with porcelain tubes, I could neither confine the carbonic acid entirely, nor expose the carbonate in them to strong heats, I at last determined to lay them aside, and return to barrels of iron, with which I had for- merly obtained some good results, beta ta: perhaps, by some accidental circumstances. On the 12th of February 1803, I began a series of expe- riments with gun-barrels, resuming my former method of working with the fusible metal, and with lead; but altering - the position of the barrel from horizontal to vertical, the breech being placed upwards during the action of heat on the carbonate. This very simple improvement has been pro-+ ductive of advantages no less remarkable than in the case of the tubes of porcelain. In this new position, the included air, quitting the air tube on the fusion of the metal, and rising to the breech, is exposed to the greatest heat of the furnace, and must therefore re-act with its greatest force; whereas, in the borizontal position, that air might go as far back as the fusion of the metal reached, where its elasticity would be much feebler. The same disposition enabled me to keep the muzzle of the barrel plunged, during the action ‘of heat, in a vessel filled with water; which contributed very much both to the convenience and safety of these ex- periments, In this view, making use of the brick furnace with the Te vertical 292 Effects of Heat modified by Compression. vertical muffle, already described in page 197, I ordered a pit (aaa, fiz. 20.) to be excavated under it; for the purpose of recciving a water vessel. This -vessel (represented sepa- rately, fig. 21:)Wwas made of cast iron} it was three inches in diameter, and three feet deep ; and had a pipe (de) striking off from it at right angles, four or five inches below its rim, communicating rosin acup (ef) at the distance of oat two feet. The main vessel being placed in the pit (aa) directly below the vertical muffle, and the cup standing clear of the furnace, water poured into the cup flowed into the vessel, and could thus conveniently be made to stand at any level. (The whole arrangement is represented in fig. 20.) The muzzle of the bate el (g) being plunged into the water, and its breech (4) reaching up into whe muffle, as far as was found convenient, its position was secured by an iron chain (gf). The heat communicated downwards generally. kept the sur- face of the water (at ¢) ina state of ebullition; the waste thus occasioned being supplied by means,of the cup, into which, if necessary, a constant stream could be made to flow. , As formerly, I rammed the carbonate into a tube of porce- Jain, and placed it in a cradle of iron, along with an air-tube and a pyrometer; the cradle being fixed toa rod of iron, which rod I now judged proper to make as large as the bar- rel would admit, in order to exclude as much of the fusible metal as possible ; for the-expansion of the liquid metal being in proportion to the quantity heated, the.more that quantity could be reduced, the less risk there was of destroying the barrels. . ikon , In the course of practice;a sunple, mode occurred of re- moving: the metal and. withdrawing the cradle : : it consisted in placing the-barrel with, its milzale downwards, so as to keep the breech above the furnace and;cold, whileits muzzle was exposed to strong heat in‘the muffle. In this manner the metal was dischar and from the muzzle, and the position of the barrel being loteened by degrees, the whole metal, was removed in suceession, till at last the,eradle and its contents became entirely loose. As the metal was delivered it was received ina erucible filled with water;, standing on a plate of. Effects of Heat modified ly Compression. 293 of iron placed over the pit,’ Which had been used, during the first stage ‘of the experiment, to contain the’ water vessel. It was found to be of service, especially where lead was used, to give much more heat to the’ muzzle than simply what was required’ to’ iquefy the metal it contained; for when ‘this was not:done, the muzzle growing cold’ as the breech was heating, ‘some of the metal delivered from the breech was congedled at the muzzle, so as to stop the passage. “Acéording to this method, ‘many experiments were made im gun2barrels, by which’ some ea material steps were’ gained i in the investigation. On the 24th of Febreary I made an experiment with spar and chalk; thé spar being placed’ nearest to the breech of the barrel, and exposed to the’ greatest heat, some baked clay intervening between the carbonates. On opening the barrel, a long continued hissing noise was heard. The spar was In a state of entire calcination; the chalk, though crumbling at the outside, was uncommonly hard and firm in the heart. The temperature had risen to 32°. In this experiment we have the first clear example, in iron barrels, of what I call internal calcination; that is to ‘say, where the carbonic acid, separated from the earthy basis, has been accumulated in cavities within the barrel. For, subsequently to the action of strong heat, the barrel had been completely cooled; the air, therefore, introduced by means of the air tube, must have resumed its original bulk, and by itself could have no tendency to rush out; the heat employed to open the barrel being barely sufficient to soften the metal. Since, then, the opening of the barrel was ac- companied by the discharge of elastic matter m great abun- dance, it is evident that this must have proceeded from something superadded to the air originally included, which could be nothing but the carbonic acid of the carbonate. If follows, that the calcination had been, in part at least, in- ternal; the separation of the acid from the earthy matter being “complete: where the heat was sttompests and oat aul tial where ‘the intensity was less.” ; The chémical principles stated ina former part of this paper, ‘authorised us to expect a result of this kind. As T 3 he?’ \ i 294 Effects of Heat modified by Compression. ' heat, by increasing the volatility of the acid, tended to se~ parate it from the earth, we had reason to expect, that, under the same compression, but in different. temperatures, one portion of the carbonate might be calcined, and another not: and that the least heated of the two would be least ex- posed toa change, not only from want of heat, but likewise in consequence of the calcination of the other mass; for the carbonic acid. disengaged by the calcination of the hottest of the two, must have added to the elasticity of the confined © elastic fluid, so as to produce an increase of compression. By this means the calcination of the coldest of the two might be altogether prevented, and that of the hottest might be hindered from making any further advancement. This reasoning seemed to explain the partial calcinations which had frequently occurred where there was no proof of leak- age; amd it opened some new practical views in these expe- riments, of which I availed myself without loss of time. _ If the internal calcination of one part of an inclosed mass pro- motes the compression of other masses included along with it, I conceived that we might forward our views very much by placing a small quantity of carbonate, carefully weighed, in the same barrel with a large quantity of that substance ; and by arranging matters so that the small fiducial part should undergo a moderate heat, while a stronger heat, ca- pable of producing internal calcination, should be applied to the rest of the carbonate. In this manner I made many experiments, and obtained results which seemed to confirm this reasoning, and which were often. very satisfactory, though the heat did not always exert its greatest force where. . I intended it to do so. On the 28th of February I introduced some carbonate, accurately weighed, into a small porcelain tube, placed within a larger one, the rest of the large tube being filled with pounded chalk; these carbonates, together with some pieces of chalk, placed along with the large tube in the cra~ dle, weighing in all 195°7 grains. On-opening the barrel, air rushed out with a long-continued hissing noise. The contents of the little tube were lost by the intrusion ef some borax which had been introduced over the silex in order to exclude 4 Effects of Heat modified by Compression. 295 exclude the fusible metal. But the rest of the carbonate, contained in the large tube, came out in a fine state, being porous and frothy throughout; sparkling every where with facettes, the angular form of which was distingnishable in some of the cavities by help of a lens: in some parts the substance exhibited the rounding of fusion ; in many it was in a high degree transparent. It was yellow towards the lower end, and at the other almost colourless. At the upper end the carbonate seemed to have united with the tube, and at the places of contact to have spread upon it, the union having the appearance of a mutual action. The’ general mass of carbonate effervesced in acid violently, but the thin stratum immediately contiguous to the tube, feelly, if at all. On the 3d of March I introduced into a very clean tube of porcelain 36°8 of chalk. The tube was placed in the upper part of the cradle, the remaining space being filled with two pieces of chalk, cut for the purpose; the upper- most of these being excavated, so as to answer the purpose of an air-tube. The pieces thus added were computed to weigh about 300 grains. There was no pyrometer used, but the heat was guessed to be about 30°. After the barrel had stood during a few minutes in its delivering position, the whole lead, with the rod and cradle, were thrown out with a smart report, and with considerable force. . The lowermost piece of chalk had scarcely been acted upon-by heat. The upper part of the other piece was in a state of marble, with some remarkable facettes, The carbonate in the little tube had shrunk very much during the first action of heat, and had begun tq sink upon itself by a further advancement to- wards liquefaction, The mass was divided into several ey- linders, lying confusedly upon each other; this division arising from the manner in which the pounded chalk was rammed into the tube in successive portions. In several places, particularly at the top, the carbonate was very porous, and full of decided air-holes, which could not have been formed but in a soft substance; the globular form and shining surface of all these cavities clearly indicating fusion. The substance was semi-transparent; in some places yel- low, and in some colourless. When broken, thegolid parts T4 showed 296 Effects of Heat modified by Compression. showed a saline fracture, composed of innumerable facettes. The carbonate adhered, from end to end, to the tube, and incorporated with ‘it, so as to render it impossible to ascer= tain what loss had been sustained. In general, the line of contact was of a brown colour; yet there was no room for suspecting the presence of any foreign matter, except, per- haps, from the iron rod which was used in ramming down the chalk. But, in subsequent experiments, T have observed the same brown or black colour at the union of the carbo-_ nate with the ‘porcelain tubes, where the powder had been purposely rammed with a piece of wood; so that this co- Jour, which has occurred’in almost’ every similar case, re=. mains to be accounted for. The carbonate ‘effervesced vio- lently with acid; the substance in contact with the tube doing so, however, more feebly than’in the heart, leaving a copious deposit of white sandy matter, which is doubtless a part of the tube, taken up by the carbonate in fusion. On the 24th of March I made a similar experiment in a stout gun-barrel, and took some care, after the application of heat, to cool the barrel slowly, with a view to crystalliza= tion. The-whole mass was found in a fine state, and un- touched by the lead; having a semi-transparent and saline structure, with various facettes, In one part’ I found the most decided crystallization I had obtained, thouch of a small size: owing to its transparency it was not easily vi-. sible till the light was made to reflect from the crystalline surface, which then produced a dazzle, very observable by the naked eye: when examined by means of a lens, it was seen to be composed of several plates, broken irregularly in the fracture of the specimen, all of which are parallel to each other, and reflect under the same angle, so as to unite in producing the dazzle. This structure was observable equally well in both parts of the broken specimen. In a former ex- periment, as large a facette was obtained in a picce of solid chalk; but this result was of more consequence, as having deen produced from chalk previously pounded. The foregoing experiments proved the superior efficacy of iron vessels over those of porcelain, even where the thickness was not great; and I persevered in making a great many experiments Effects of Heat modified by Compression. 207 experiments with gun-barrels, by which I occasionally ob- tained very fine results: but I was at last convinced that their thickness was not sufficient to ensure regular and steady success. For this purpose it appeared proper to em- ploy vessels of such strength, as to bear a greater expansive force than was just necessary ; since, occasionally (owing to our ignorance of the relation between the various forces of expansion, affinity, tenacity, &c.), much more strain has been given to the vessels than was requisite.. In such cases barrels have been destroyed, which, as the results have proved, had acted with sufficient streneth during the first stages of the experiments, though they had been unable to resist the subsequent overstrain. Thus my success with gun- barrels depended on the good fortune of having used a force no more than sufficient to constrain the carbonic acid, and enable it to act as a flux on the lime. I therefore deter- mined to have recourse to iron barrels of, much greater streneth, and tried various modes of eoHBER Eton! ’ Thad some barrels executed by wrapping a thick plate of iron round a mandrel, as is practised in the forrnation of gun-barrels ; and likewise by bringing the two flat sides to- gether, so as to unite them by welding. These attempts, however, failed. I next thought of procuring bars of iron, and of having a cavity bored out of the solid, so as to form a barrel. In this manner I succeeded well. The first barrel I tried in this way was of small bore, only half an inch: ‘its performance was highly. satisfactory, and such as to con- vince me, that the mode now adopted was the best of any that I had tried. Owing to the smallness of the bore, a py- rometer could not bé used internally, but was placed-upon the breech of the barrel, as it stood in the vertical mu‘fle. In this position it was evidently exposed to a much less liea than the fiducial part of the apparatus, which was always placed, as nearly as could be guessed, at the point of greatest heat. On the 4th of April an experiment was made in this way with some spar, the pyrometer on the breech giving 33°. The spar came out clean, and free from any contamination, adhering 298 . Effects of Heat modified by Compression: adhering to the inside of the porcelain tube: it was very, much ‘shrunk, still retaining a cylindrical form, though bent by partial adhesions. Its surface bore scarcely any re- mains of the impression taken by the powder on ramming ~ it into the tube: it had, to the naked eye, the roughness and semi-transparency of the pith of a rush stripped of its*outer skin. By the Jens this same surface was seen to be glazed all over, though irregularly, showing here and there some -air-holes. In fracture it was semi-transparent, more. vi- treous than crystalline, though having a few facettes: the mass was seemingly formred of a congeries of parts, in them- selves quite transparent; and, at the thin edges, small pieces were visible of perfect transparency. These must have been produced in the fire; for the spar had been ground with water, and passed through sieves, the same with the finest of those used at Etruria, as described by Mr. Wedgewood, in his paper on the construction of his pyrameter. With the same barrel I obtained many interesting results, giving as strong proofs of fysion as in any former experi- ments; with this remarkable difference, that, in these last, the substance was compact, with little or no trace of froth- ing. In the gun-barrels where fusion had taken place, eke had always been a loss of 4 or 5 per cent., con- nected, probably, with the frothing. In these Pe ictirapien for a reason soun to be stated, she circumstance of weight could not be observed; but appearances. led me.to suppose, that here the loss had been small, if any, : On the 6th of April I made another experiment with the square harrel, whose thickness was now much reduced by successive scales, produced by oxidation, and in which a small rent began to appear externally, which did not, how- ever, penetrate to the bore. The heat rose high, a pyro- meter on the breech of the barrel giving 37°. On removing the metals, the cradle was found to be fixed, and was broken in the attempts made to withdraw it. The rent was much widened externally: but it was_evident that the barrel had not been laid open, for part of the carbonate was in a state of saline marble; another was hard and white, without any saline . Effects of Heat modified by Compression. 299 saline grains, and scarcely effervesced in-acid. It was pro- bably quicklime, formed by internal calcination, but ina State that has not occurred in any other experiment. The workman whom I employed to take out the remains of the cradle, had cut off a piece from the breech of the bar- rel, three or four inches in length. As I was examining the crack which was seen in this piece, I was surprised to see the inside of the barrel lined with a set of transparent and well defined crystals, of sinall size, yet visible by the naked eye, They lay together in some places, so as to cover the Surface of the iron with a transparent coat; in others they were detached, and scattered over the surface. Unfortu- nately, the quantity of this substance was too small to admit _of much chemical examination; but I immediately ascer- tained that it did not in the least effervesce in acid, nor did it seem to dissolve in it. The crystals were in general trans- parent and colourless, though a few of them were tinged seemingly with iron. Their form was very well defined, being flat, with oblique angles, and bearing a strong resem- blance to the crystals of the lamellated stylbite of Haiiy. Though made above two years ago, they still retain their form and transparency unchanged. Whatever this sub- stance may be, its appearance, in this experiment, is in the highest degree interesting, as it seems to afford an example of the mode in which Dr. Hutton supposes many internal cavities to have been lined, by the sublimation of sub- stances in a state of vapour, or held in solution by matters in a gaseous form. For, as the crystals adhered to a part of the barrel, which must have been occupied by air during the action of heat, it seems next to certain that they were pro- dueed by sublimation. The very powerful effects produced by this Jast barrel, the Size of which (reduced, indeed, by repeated oxidation) was not above an inch square, made me very anxious to obtain barrels of the same substance, which, being made of greater size, ought to afford results of extreme interest. I found, upon inguiry, that this barre] was not made of Swedish iron, as I at first supposed, but of what is known by the name of | qld sable, from the figure of a sable stamped upon the bars; that 300 Effects of Heat modified by Compresston. ; that. ‘being the ‘armorial sae of the ite in Sigerve ae this iron is made* A workman explained to me some of the properties of different kinds of irons; most interesting in my present pur- suit; and ‘he ilustrated what he said by actual trial,” All iron, when exposed to-a certain heat, crushes and crumbles under the hammer; but the temperature in which this hap- pens, varies with every different species. Thus, as he showed me, cast iron’ crushes in a dull red heat, or perhaps about 15° of Wedgewood; steel in‘a heat, perhaps, of 30°; Swe- dish iron, ina’ bright white heat, perhaps of 50° or 60°; old sable itself likewise’ yields, but in a much higher heat, perhaps of 100°.°"T merely guessed at these temperatures ; but Tam ‘certain’ of this, that in a heat similar to that in which Swedish iron cru mbled under the hammer thé old, sable withstobd a strong ‘blow, and seemed to possess ¢on= siderable firmness. It is from a knowledge of this quality that theblacksmith, when he first takes his iron from the forge, ‘atid Hays it on the anvil, begins'hy very gentle blows, till the temperature vas suiik to’ the degree in'which the: iron can bear thé hamimer. 1 observed, as the strong heat of the forge acted on the Swedish iron, that it began to boil at the surface,. clearly indicating the discharge of some: gaseous. matter; whereas, the old Sables in the same circamstanees, aequited the’ shining surface of a hquid, and melted away without any effervescence. I procured, at this tirne, a con- sjderable number of bars of that iron, which fully answered my expectations. : By the experiments last mentioned, a very important point was gained in this investigation ; the complete fusi- bility of the carbonate under pressure being thereby esta- Blished. But from this very circumstance a necessity arose of adding some new devices to those already described’: for the carhonate, i in fusion, spreading itself on the’ inside of the tube containing it, and the two uniting firmly together, so as to be quite inseparable, it was impossible, after the: ex periment, to ascertain the weight of the carbonate by any * I was favoured with this account of it by the late professor eiteon: methad Effects of Heat modified by Compression. 301 method previously,used. I therefore determined in future to adopt the following arrangement. 4 , A small tube of feta (1, fig, 23.) was weighed by means of a counterpoise of sand, or granulated tin; then the carbonate. was firmly rammed into the tube, and the whole weighed again: thus the weight of the carbonate, previous to the experiment, was ascertained. . After the ex- periment, the tube, with its contents, was again weighed ; and the variation of weight obtained, , independently of any mutual action that had dan place between the, tube and the carbonate. The balance. which ‘I. used? turned, a constant and steady manner, with one hundredth aaa 2 grain. When pounded chalk was rammed into ‘this tube, i generally left part of. it free, and in that, space laid.a small piece of lump chalk (7), dressed to a cylinder, with the ends cut flat and smooth ; and J usually cut a letter on ach end, the more effectually to observe the effects produced by heat upon the chalk; the weight of this piece of chalk being al- ways estimated along with that of the powder contained in the tube. In some experiments I placed a cover of porce- Jain on the muzzle of the’ little tube, (this cover being weighed along with it,) in order to provide against the case of ebullition: but as that did not often occur, I seldom took the trouble of this last precaution. It was now of consequence to protect the tube, thus pre- pared, from being touched during the experiment by any substance, above ‘all by the cud wanate of lime, which might adhere to it, and thus confound the appreciation by weight. This was provided for as follows: The small tube (fig. 23. ik), with its pounded carbonate (2), -and its mylitidey of lump-chalk (i), was dropt’ into a large tube: of porcelain (pk, fig. 24). Upon this a fragment of porcelain (1), of such asize as not to fall in between the tubes, was laid. ‘Then a cylinder of chalk (7) was dressed, go.a3 nearly te y ’ ; fit and fill up the inside of the-large tube; oneend of it heimg rudely cut into the form of aicones This mass being ther introduced, with its cylindrical. end downwatds,: was: made to press upon the fragment of-porcelain, (2). 4 then dropped » pato.the space (m), between thé conical part ‘off this? mass eh and * 302 Effects of Heat modified by Compression. and the tube, a set of fragments of chalk, of a size beyond what could possibly fall between the cylindrical part and the tube, and pressed them down with a blunt tool, by which the chalk being at the same time crushed and rammed into the angle, was forced into a mass of some solidity, which effectu- ally prevented any thing from passing between the large mass of chalk and the tube. hi practice, I have found this method always to answer, when done with care. I covered the chalk, thus rammed, with a stratum of pounded flint (0), and that again with pounded chalk (p) firmly rammed. Tn this manner T filled the whole of the large tube with alternate layers of silex and chalk ; the muzzle being always occupied with chalk, which was easily pressed into a mass.of tolerable firmness, and, suffering no change in very low heats, excluded. the fusible metal in the first stages of the experiment. The large tube, thus filled, was placed in the cradle, sometimes with the muzzle upwards, and sometimes: the reverse. Ihave frequently altered my views as to that part of the arrangement, each mode possessing peculiar advan- tages and disadvantages. With the muzzle upwards, (as shown in fig. 24. and 25.) the best security is afforded against the intrusion of the fusible metal; because the air, quitting the air-tube in the working position, occupies the upper part of the barrel ; and the fusible metal stands as a liquid (at g, fig. 25.) below ‘the muzzle of the tube, so that all communication is cut off between the liquid metal and the inside of the tube. On the other hand, by this arrange- ment, the small tube, which is the fiducial part of the ap- paratus, is placed ‘at a considerable distance from the breech of the barrel, so as either to undergo less heat than the upper part, or to render it necessary that the barrel be thrust high into the muffle. With the muzzle of the large tube downwards, the inner tube is placed (as shown in fig. 22.) so as still to have its muzzle upwards, and in contact with the breech of the large tube. This has the advantage of placing the small tube near to the breech of the barrel: and though there is here less security against the intrusion of liquid metal, I have found that a point of little consequence; since, when the Effects of Heat modified by Compression. 303 the experiment is a good one, and that the carbonic acid has been well confined, the intrusion seldom takes place in any position. In whichever of the two opposite positions the large tube was placed, a pyrometer was always intro- duced, so as to lie as near as possible to the small tube. Thus, in the first-mentioned position, the pyrometer was placed immediately below the large tube, and, in the other position, above it; so that, in both cases, it was separated from the carbonate by the thickness only of the two tubes. Much room was unavoidably occupied by this method, which necessarily obliged me to use small quantities of car- bonate; the subjcet of experiment seldom weighing more than 10 or 12 grains, and in others far less *. On the 1ith of April 1803, with a barrel of old sable iron, having a bore of 0°75 of an inch, I made an experi- ment in which all these arrangements were put in practice. The large tube contained two small ones; one filled with. - spar, and the other with chalk. I conceived that the heat ‘had risen to 33°, or somewhat higher. On melting the metals, the cradle was thrown out with considerable vio- lence. The pyrometer, which, in this experiment, had been placed within the barrel, to my astonishment indicated 64°. Yet all was sound. The two little tubes came out quite clean and uncontaminated. The spar had lost i7°0 per cent.; the chalk 10°7 per cent. The spar was half sunk down, and run against the side of the little tube: its surface was shining, its texture spongy, and it was composed of a transparent and jelly-like substance : the chalk was entirely in a state of froth. This experiment extends our power of action, by showing, that compression, to a considerable de~ gree, can be carried on in so great a heat as 64°. It seems likewise to prove, that in some of the late experiments with * I measured the capacity of the air-tubes by means of granulated tin, acting as a fine and equal sand. By comparing the weight of this tin with an equal bulk of water, | found that a cubic inch of it weighed 1330°6 grains, and that each grain of it corresponded to 0:00075 of a cubic inch. From these datal was able, with-tolerable accuracy, te gauge a tube by weighing the tia required to fill it. the 304 Effects of Heat modified by Compression. the square barrel, the heat had been much higher tham wag supposed at the time, from. the indication of the pyrometer placed on the breech of the barrel ; and that in some of them, part ‘cularly in the last, it must have risen at least as high as in the present experiment. ‘On the 2tst‘of April 1805, a similar experiment was made with a new barrel, bored ina square bar of old sable of about two inches and a half in diameter, having its angles merely rounded, the inner tube being filled with chalk. The heat) was maintained during several hours, and the furnace allowed to burn out during the night. The barrel had ithe appearance of soundness, but the metals came off quietly, and the carbonate was entirely calcined, the pyrometer in- dicating 63°. On examination, and after beating off the smooth and even scale of oxide peculiar to the old: sable, the barrel was found to have yielded in its peculiar manner ; that is, by the opening of the longitudinal fibres. This ex- periment, notwithstanding the failure of the barrel, was one of the most interesting I had made, since it afforded proof of complete fusion. The carbonate had boiled over the lips of the little tube, standing, as just described, with its mouth upwards, and had run down to within half an inch of its Jower end: most of the substance was ina frothy state, with large round cavities, and a shining surface ; in other parts it was interspersed with angular masses, which have evi- dently been surrounded by a liquid in which they floated. It was harder, I thought, than marble; giving no effer- vescenee, and not turning red like quicklime in nitric acid, which seemed to have no effect upon it in the lump. It was probably a compound of quicklime with the substance of the tube. With the same barrel repaired, and with others like it, — many similar experiments were made at this time with great success; but to mention them in detail, would amount nearly ‘# a repetition of what.has been said. I shall take notice of only four of them, which, when compared toge- ther, throw much light on the theory of these operations, and jikewise seem to establish a very important principle in geology. 7 a Effects of Heat modified by Compression. 305 geology. These four experiments differ from each other enly in the heat employed, and in the quantity of air intro- duced. The first of these experiments was made on the 27th of April 1803, in one ofthe large barrels of old sable, with all the above-mentioned arrangements. The heat had risen, contrary to my intention, to 78° and 79°. The tubes came out uncontaminated with fusible metal, and every thing bore the appearance of soundness. The contents of the little tube, consisting of pounded chalk, and of a small piece of Jump chalk, came out clean, and quite loose, not having adhered to the inside of the tube in the smallest degree. There was a loss of 41 per cent., and the calcination seemed to be complete ; the substance, when thrown into nitric acid, turning red, without effervescence, at first, though, after lying a few minutes, some bubbles appeared. According to the method followed in all these experiments, and lately described at Jength, (and shown in fig. 24. and 23.) the large tube was filled over the small one, with various masses of chalk, some in Jump, and some rammed into it in pow- der; and in the cradle there lay some pieces of chalk, filling up the space, so that in the cradle there was a continued chain of carbonate of four or five inches in length. The substance was found to be less and less calcined, the more it was removed from the breech of the barrel, where the heat was greatest. A small piece of chalk, placed at the di- stance of half an inch from the small tube, had some saline substance in the heart, surrounded and intermixed with quicklime, distinguished by its dull white. In nitric acid this substance became red, but effervesced pretty briskly ; the effervescence continuing till the whole was dissolved. The next portion of chalk was in a firm state of limestone ; and a lump of chalk in the cradle was equal in perfection to any marble I have obtained by compression; the two last- mentioned pieces of chalk effervescing with violence in the acid, and showing no redness when thrown into it. These facts clearly prove that the calcination of the contents of the small tube had been internal, owing to the violent heat: Vol. 24. No. 96. May 1806. U which 306 Effects of Heat modified by Compression. which had separated its acid from the tnost heated part of the carbonate, according to the theory already stated. The soundness of the barrel was proved by the complete state of those carbonates which lay in Jess heated parts. The air- tube in this experiment had a capacity of 0°29, nearly one- third of a cubic inch. The second of these experiments was made on the 29th of April, in the same barrel with the last, after it had af- forded some good results. The air-tube was reduced to one- third of its former bulk, that is, to one-tenth of a cubic inch. The heat rose to 60°. The barrel was covered externally with a black spongy substance, the constant indication of failure; and a small drop of white metal made its appear- ance. The cradle was removed without any explosion or hissing. The carbonates were entirely calcined, The barrel had yielded, but had resisted well at first; for the contents of the little tube were found in a complete state of froth, and running with the porcelain. ‘The third experiment was made on the 30th of April in another similar barrel. Every circumstance was the same as in the two last experiments, only that the air-tube was now reduced to half its last bulk, thatis, to one-twentieth of acubic inch, A pyrometer was placed at each end of the Jarge tube. The uppermost gave 41°, the other only 15°. The contents of the inner tube had lost 16 per cent., and were reduced to a most beautiful state of froth, not very - much injured by the internal caicination, and indicating a thinner state of fusion than had appeared. The fourth experiment was made on the 2d of May, like the rest in all respects, with a still smaller air-tube, of 00318, being less than one-thirtieth of a cubic inch. The upper pyrometer gave 25°, and the under one 16°. The lowest masses of carbonate were scarcely affected by the heat: the contents of the. litile tube had lost 2°9 per cent. ; both the lump and the poynded chalk were in a fine saline state, and in several places had run and spread upon the inside of the tube, which J had not expected to see in such 2 low heat. , On the upper surface of the chalk rammed into the Effects of Heat modified ly Compression. 307 "the little tube, which after its introduction had been wiped smooth, were a set of white crystals, with shining facettes, large enough to be distinguished by the naked eye, and seeming to rise out of the mass of carbonate. I likewise observed that the solid mass on which these crystals stood was uncommonly transparent. In these four experiments the bulk of the included air was successively diminished, and by that means its elasticity in- creased. The consequence was, that in the first experiment, where that elasticity was the least, the carbonic acid was allowed to separate from the lime, in an early stage of the rising heat, lower than the fusing point of the carbonate, and complete internal calcination was effected. | In the se- cond experiment, the elastic force being much greater, cal- cination was prevented, till the heat rose so high as to occa- sion the entire fusion of the carbonate, and its action on the tube, before the carbonic acid was set at liberty by the failure of the barrel. In the third experiment, with still greater elastic force, the carbonate was partly constrained, and its fusion accomplished, in a heat between 41° and 15°. In the last experiment, where the force was strongest of all, the carbonate was almost completely protected from decom- position by heat, in consequence of which it crystallized and acted on the tube in a temperature between 25° and 16°. On the other hand, the efficacy of the carbonic acid as a flux on the lime, and in enabling the carbonate to act asa flux on other bodies, was clearly evinced ; since the first ex- periment proved, that quicklime, by itself, could neither be melted, nor act upon porcelain, even in the violent heat of 79°; whereas, in the last experiment, where the carbonic acid was retained, both of these effects took place in a very low temperature. [To be continued.] U2 LVI. Ol- ip [ 308 ] LVI. Observations and Advices respecting Improvements compatible with the quickest Manufacture of Muscovado Sugar, and condycive to the Melioration of the Rum. By Bryan Hiceins, M. D.¥ Sounp cane-juice consists of water, sugar, deliquescent sweet, herbaceous matter, carbonic acid, and melasses acid : and some juices contain variable quantities of other ingre- dients, which are not yet to be noticed. In these pharmaceutic ingredients subsist the primary or chemical principles of many vegetable acids. But expe- rience shows, that the composition of attractive forces, re+ sulting from such proportions of the principles as take place in the recent juice, tend chiefly to the formation of an acid similar to vinegar, and of an additianal quantity of carbonic acid and melasses acid. For in the course of 12 or 18 hours the juice mantles by the rise and escape of carbonic acid in the elastic state : at an earlier period it smells sour or acetous: and by the effect of such delay on the sugar producible from it, it is certajn that there i is an addition to the original quantity of the me- lasses acid. This last is the ingredient which most powerfully impedes the crystallization and separation of the saccharine niatter from the deliquescent sweet and mother-liquer called me- lasses. As it lessens the quantity of saccharine'crystals, and increases that of melasses mother- liquor ; and as it 1s highly probable that mclasses contain the like acid as a constituent principle, I give it the temporary name of melasses acid. _ Herbaceous matter is that of which some part shows itself in the yawing, and more in the boiling of juice which had been cleared Frau gross filth by filtration, It is that which we endeavour to separate from the saccharine liquor by yaw- ing and skimming. The herbaceous matter has some analogy to gummy re- sins, but has a much nearer similitude, in chemical cha- racter, to the dregs of refined indigo, or that vegetable sub- * From Part I. of Dr. Higgins’s Observations, &c. published in Jamaica. 5 aa : stance On the Manufacture of Muscovado Sugar. 809 stance which constitutes the chief difference between the finest and the basest indigo. The herbaceous matter of cane-juice, like that of indigo, | varies with the constitution of the plant in different soils and seasons, and especially in respect to its solubility 3 insomuch that some juices hold about ;1,dth part of it in strict solu- tion after boiling, while others hold not 1000dth. But as herbaceous matter is rendered more soluble by the interverttion of carbonic acid, any cane-juice holds more herbaceous matter in solution before it has been heated, than it can retain at the temperature of yawing or boiling. For in the augmented temperature the carbonic acid for- sakes the herbaceous matter to combine with that which makes the acid aériform; the minute gaseous bubbles in their escape agitate and impel the particles lately thrown out of solution, until in their coalescence they become not only visible but large. We may express this change in the clear recent juice by the agency of fire alone, as the workmen do, by saying the liquor breaks. Fresh cane-juice begins to break when the heat approaches to 140 degrees of Fahrenheit 5. and the herbaceous matter, which has felt no greater heat, has an olive green colour. Whether this be exposed to greater heat, or we advert to that which is thrown out during the subsequent reduction of the juice to sugar, the herbaceous matter is found to change colour with the increase of temperature, through gradations of yellow, olive, and brown, increasing in inten- sity and darkness until the matter is charred to blackness. As it changes in colour it becomes less soluble. The car- bonic acid continues to escape, and the extricated herbaceous matter accumulates to the surface, while the liquor is heated to 195°. Now the watery vapour arising with the carbonic acid bubbles, pushes the cleansed liquor: frothing white through intervals in the swollen scum. This, which is called yawing, shows that a greater heat would cause a boiling commotion: but if some time be allowed for the residuary carbonic acid to escape, the liquor will not boil until this heat amounts to 206°, or within five degrees of the heat of boiling water. 3U 3 The 316 On the Manufacture of Muscovado Sugar. The aériform bubbles entangled in the herbaceous matter render it more buoyant than it would otherwise be, and en- .able it to carry with it, and to sustain at the surface, any accidental filth of the liquor: and the scum thus produced is by its own nature sufficiently tenacious to be separable by the skimmer, or by drawing away the depurated juice from beneath it. But, if the buoying bubbles be expelled by greater heat and the commotion of boiling, the scum will be broken into the liquor. . The skimmer will now avail nothmg; but the herbaceous miatter, once thrown out of solution, will subside with the filth, in an hour, in a cooling quiescent liquor, and will leave it transparent, although it still retain that quantity of herbaceous matter, which the water, with the last adherent portions of carbonic acid, can dissolve. But as this depuration by subsidence cannot be awaited Without injury to the juice, the foul scum: ought to be re- moved before the liquor ‘boils. In consequence of this limited solubility, the residuary herbaceous matter becomes extricated afterwards in quan- tity proportionate to that of the watery solvent which is ex- pelled by evaporation, and the reduced liquor becomes tur- bid by the extricated herbaceous particles. However often the process of evaporation is stopped, and the liquor is depurated to perfect transparency, by subsi- dence or otherwise, it will become turbid again, by the deposition of herbaceous dregs, when the evaporation is renewed ; arid it will thus yield dregs to the end, or until the residuary liquor becomes so far saturated with sugar as to be incapable of holding the less soluble herbaceous matter in solution. All this takes place whether a moderate dose of temper be used or not. But the cleansing by subsidence is quickest when temper is used. To ascertain the true use of temper, we-must advert to its ‘agency on herbaceous matter, carbonic acid, and melasses vacid. Lime powerfully attracts carbonic acid: and although ais 3 : lime A ———— On the Manufacture of Muscovado Sugar. 311 lime be a soluble body, and although it meet the acids in the aériform state, it forms with it quickly an insoluble body similar to whiting or chalk. Lime also combines with a triple or quadruple quantity of herbaceous matter to form a compound less soluble than the latter in water; and in cane-juice, lime meeting car- bonic acid and herbaceous matter, unites with both to form a triple compound. For if the lime used in clarifiers were to unite with the carbonic acid only, we should find bottoms consisting of whiting, which I have looked for, but could never obtain. It is by virtue of these relations that a small quantity of lime, or transparent lime water in which the lime can be only =1;th part of the whole, when added to eane-juice that has been duly cleared, reiders it presently turbid with her-— baceous matter now extricated, and thus facilitates the abs- traction of this matter by subsidence. Thus, also, cane- juice which is a little wheyey or clouded is broken to floc~ culence by transparent lime water as well as by lime. I say the liquor is broken to flocculence when the parti- cles of herbaceous matter, seized by those of the lime, and coalescing, appear large and flocculent ; and the liquor in- terceding them is seen quite transparent when viewed by transmitted light in the narrow part of a wine-glass. This breaking may also be distinguished in a bright silver spoonful of the liquor by reflected light. On these grounds some lime ought to be added to cane- juice which contains the ordinary quantity of herbaceous Matter, not with the vain hope of separating all the herba- ceous matter at once, but with the experienced certainty that the liquor yawed or cleansed with the aid of lime, will contain Jess herbaceous matter in solution than it would otherwise have retained, and will require the less additional lime to act on the melasses acid. Towards the kind of depuration which can be effected in the process of yawing, lime thus contributes something, but not nearly so much as has been generally supposed: for a quantity of lime which is sufficient to give a nauseous taste U4 to 312 On the Manufacture of Muscovado Sugar. to the sugar, is yet incompetent to the extrication of all the herbaceous matter, so that it shall be separable by yawing or _ subsidence: and an excess of lime, not greater than 73,5dth, or s,!5¢dth of the weight of the juice, is constantly attended with a manifest debasement of the colour of the sugar, when this excess takes place in the beginning of the boiling, or previous to the reduction of the juice by evaporation. It is. of no practical use to inquire after every agency by which the excess of lime has these effects; but it is expedient to observe, that when a juice is yawed with excess of lime, and cleared to. transparency by subsidence, which soon. takes place in a specimen quickly cooled in a wine-glass, it will show colour approaching to that of porter; while the like juice, treated in the same way, but with only a moderate dose of temper, will be almost colourless when transparent. It is moreover to be observed in ordinary practice, that when too much temper has been used in the yawing, the liquor, during the boiling of the. teaches, looks much browner than that which. has been less tempered, The scum has a darker colour, and is more apt to break and sink into the liquor; and it has less of the tenacity and floc- calence by which ordinary scum clings on the skimming instrument, and is separable by the common proeess. The practical inference from all these facts is, that the temper ought to be used sparingly in the raw juice in the operation of yawing, although it should be found necessary to use more temper afterwards, for purposes different from those lately recited, -It is chiefly by reason of the agency of the temper on the melasses;acid, or on that matter w hich most powerfully im- pedes the separation of the sugar from the melasses mother- liquor, that the temper is.eminently useful in the manufac-, ture of Muscovado sugar, and that greater quantities of it may be advantageously employed, provided the whole of it be not administered at once, and at the period of the manu- facture.in' which it is apt to colour the juice, to lessen the buoyancy and. tenacity of the ‘scum, and .to, frustrate, the labour of:the skimmer., -Among the.signs which may guide an . = ww On the Manufacture of Muscovado Sugar: 313 an intelligent sugar-bciler in respect to the doses of temper, those which correspond with the foregoing observations are the simplest and most certain. When the artist knows that the quantity usefal in yawing is less than is necessary for a bold grain and speedy curing of the sugar, and is apprised of the practicability of abstract- ing all the temper that may be used afterwards im the teaches, he will not err by excess of temper in the first process. Supposing that he tempers in a grand boiler, or uses a clarifier to the same effect, he will introduce a quantity of temper rather too small than too great, when the vessel has received three-fourths of its charge. He will yaw and check the fire and skim, and then boil moderately and skim for eight or ten minutes. He will then take a wine-glass full of the liquor, and if, after cooling a little, it looks wheyey and not broken, he will use one-sixth or one-fourth of the first quantity of lime, and will immediately take a fresh sample. When the liquor appears broken, and clears with little or no colour, he has hit the precise quantity which is compatible with the cleanness and whiteness of the sugar, and which goes nearest to the whole quantity to be used for the perfection of the grain. _ By the usual ladle-proof he will soon ascertain the addi- tional quantity of temper to be used in the inspissated liquor, in the manner presently to be described. He that will not follow this rule may take a grosser, by using three-fourths of the temper in the yawing, and the remainder in the inspissated liquor. It has not been unusual for the boilers to put temper in the second and first teach, when the proof by the ladle showed that the temper used in yawing was not sufficient for the granulation of the sugar. Such temper there used was the least injurious to the colour of the sugar; but as none of it could now be separated by skimming from the thick syrup, it manifestly adulterated the sugar, and increased the quantity of filth to be seen in a solution of it. But no such objection lies against the free use of temper jn the syrup, provided we can extract all this temper and all the filth which it catches, and advance the syrup transparent 7 and - 314 On the Manufacture of Muscovado Sugar. and clear, to yield sugar emulating if not equalling ordinary coarse lump sugar, for gencral use, without abatement of the described celerity in the transition from the raw juice to sugar. For, in a just comparison of sugars to be used ceco- nomically, we are to advert, not merely to the degrees of whiteness, which may be varied by the size of the grain, but chiefly to the cleanness of equal solutions, and the sweeten- ing effects of portions equal in dryness and in weight. The common use of yellow sugar-candy, on the continent of Europe especially, shows that it is not the colour of good Muscovado sugar which has impeded the consumption of it in the crude state. It is truly the filth which appears in a solution of it, which has forbidden the culinary use of it, and depreciated it so far below lump sugar ; and it is in con- sequence of the cleaning by filtration, rather than by reason of the blanching by breaking the grain and by elaying, that the lump sugar has such preference and greater price. It is this filth, also, which compels the sugar refiner mm Europe to use ox blood in quantity proportionate to the im- purity of the Muscovado sugar ; and to encounter the labour and waste attending the abstraction of the sweets from the abundant scum, consisting of the heterogeneous matter en- “stangled in the filaments ‘of coagulated blood ; and it is the chief cause of his inability to give a price for dry Muscovado sugar, nearer to that at which he sells the ordinary lump sugar. Of the Improvement of Filtration. It will therefore be the first of all services for this ssbiesd; and it will be the most desirable character of Jamaica sugar, that it be made clean by the mere means of line and filtra- tion, which are employed in the manufacture of the finest lump sugar; and, until this character is established, little or nothing ought to be said concerning the other tempers and expedients which may be aden aseoasly mead in pa circumstances. ‘ As the true meaning of the word filtration is not under- stood by all, and doubts and controversies may arise’ from the mere abuse or misconception of the term, itis expe- dient that it should be defined in a manner suitable’to all the : ; workmens On the Manufacture of Muscovado Sugar. 315 workmen, to whom these pages may ultimately be commu- nicated. When a foul liquor is passed through a fine wire sieve, or through a blanket, which stops the coarse filth, but not the finer, and where the liquor so treated stil remains clouded or turbid, this is called straining: but when a me- dium, such as close cloth or unsized paper, is used, and this stops all extricated filth and passes the aks transparent, the process is called ti liration. In the refineries in Europe a blanket serves as a filter, but not before the filth of the solution of Muscovado sugar has been entangled in flocks. of coagulated ox blood, too large to pass through the interstices of a blanket. The use of such a woollen strainer has been tried in this island, but is generally abandoned for good reasons. A blanket only strains the boiled cane-juice, while it passes with the velocity necessary for the manufacture of good Muscovado sugar. When the interstices of the blan- ket are narrowed by coarse flocculent filth, and when it be- gins to filtrate truly, the process becomes so slow as to re- tard the manufacture intolerably: the last portions refuse to pass through; the quantity of sweets retained in and ona Jarge thick blanket makes a great defalcation from the sugar, and the cleansing of the cloth is laborious. To make the process of filtration applicable in the manu- facture of Muscovado sugar, it was necessary that a medium should be employed capable of filtrating truly at the begin- ning. It was equally necessary that the velocity of this fil- tration should be equal to that with which the liquor would pass turbid through a coarse strainer of the same dimen- sions. It was moreover requisite, for the reasons abave mentioned, that this rapid filtration should be confined to that period in which all the herbaceous matter is thrown out of solution, and in which the liquor is viscid with sugar. These desiderata are attained in the invention lately pre- sented undcr trial to as many of the honourable members of the appointed committees as could be assembled at the time and place. , {n this first mechanism the proof of the principles and powers 316 On the Manufacture of Muscovado Sugar. powers was chiefly attended to: in the instruments whicli are now to be made, the utmost convenience will be at- tained; and from these only the descriptions and models, which I shall soon lay before the honourable members, are to be made. At the present moment I must content myself. with pre- senting a few lines descriptive of the principles upon which a small simple filtrating instrument is competent to the in- tended uses. In ordinary cases, the power by which the liquor is pressed through the interstices of a filtrating cloth is merely the weight of the liquor; and, under equal pressures by weight, the velocity of filtration is as the extent of filtrating cloth. But, as in ordinary vessels used for this purpose, the pressure on a given area of the filtrating surface increases with the height of the liquor above it, omitting nice discussions, we may affirm generally, that the velocity of filtration is as the number of square inches of filtrating cloth multiplied by the height of the contained pressing fluid ; therefore, in order to attain any required velocity of filtration, the height of the pressing column may be made to compensate for any de- sirable reduction of the size of the cloth. Supposing, for instance, a cloth measuring 8 feet by 72, or 60 square fect in area, could filter fast enough under a charge of liquor measuring 3 inches in depth, one-sixth of this cloth, or 10 square feet of it, would serve if the column or charge of liquor pressing on it were made to be 18 inches in height: and with the height of 36 inches, 5 square feet would serve; and this is less than the measure of a common pocket handkerchief. By the like reasoning it will be found, that if the cloth of 60 square fect filter no ‘quicker than is necessary for the pro- gress of the manufacture, the filtration will become slower as the liquor lowers to a smaller area of filtrating surface, and still slower as the height of the pressing liquor de- creases; so that at.the height of one inch, the quantity fil- trated in a given time would be much less than one-third of that which the progress of the work would require. But when it is considered that filtration will not avail much On the Manufacture of Muscovado Sugar. 317 much until the liquor is rich and viscid with sugar $ that every filtration abates as the interstices of the cloth become narrowed, or clogged with filth; and that a rich saccharine liquor expanded on a large cloth in a basket, in the usual mode of filtration, will soon be chilled, and incapable of passing through the chilled and agglutinated filth; it will readily appear that the quantity of sweets retained in and upon the cloth would cause an enormous defalcation of the sugar, and great labour in washing out the sweets for the stillhouse, and the filth from any great filter, We are to revert, then, to the small filter above mentioned, acting by ihe pressure of a high column of liquer, in order to obviate the described inconveniences, It may appear paradoxical at the first view, but it is a fact demonstrated in every school-book of natural philosophy, that the pressure of the liquor on the filter is the same whe- ther the superincumbent column consists of a ton or of a pint of the liquor, provided the heights of these columns be equal. Therefore, instead of making an instrument to give a ton of pressure, by containing about a ton, or 250 gallons of liquor, I have given an equivalent pressure by a pint or two contained in a slender perpendicular tube: and instead of setting the filtrating bag to a great capacity, I have set it vertical, flat, and with the opposite parallel sides so near to | each other, as to leave room only for the filth to be collected from half a ton or a ton of sugar. By such mechanism and pressure the juice may be fil- trated truly and expeditiously, even when it is so rich and viscid witu sugar that it could not pass through any filtrat- ing medium used in the ordinary way. The filtration keeps pace with the ladling forward, when the cloth measures about 10 or 12 feet square, and the flattened bag about 5 square feet: and the same bag will clean from 10 to 15 or 20 hundred weight of sugar, according to the nature of the juice and the care of the workman in the previous de~ purations by yawing and skimming. By these means, also, the whole quantity of liquor in the filter at any time may fall short of a gallon; and the quan- — tity 318 On the Manufacture of Muscovado Sugar. tity retained when the bag becomes stuffed and clogged with filth is too inconsiderable to deserve notice, even if the wash- ings were not to go to the still-house. For the described pressure of the slender column of the liquor is, or may he, made competent to squeeze the filth with a force equal to that of one, two, or three tons weight, and to reduce it to the consistency of dough, if that were necessary. The cloth which answers for this purpose by its closeness, and durability, and cheapness, is a kind of flannel called double swanskin: it is sewed to form a bag: the bag is placed flat between two reeded or fluted faces of wood: the mouth of the bag is perfectly closed, by giving it one fold or fell to be compressed by the reeded faces. The liquor is supplied from the slender pressing column by a smal] stop- cock entering a small short tube of swanskin belonging to the bag: by drawing a little of this tube over its orifice, the ligature becomes closer as the pressure of the liquor becomes greater. It is easy to conceive how quickly such a filter may be slung into its place or removed for washing, or to make way for another that is already washed. To prevent fruitless experiments and expenses it is neces- sary to observe, that in any position different from the ver- tical now described, the bag will not act as a filter, and will only strain the liquor, and that, if the reeding be not ver- tical, the filtration will be slow. When liquor is to be thrown forward, it is, in the general course of business, to be ladled from the second teach into the instrument, by the gutter, off which it will run clear and quickly into the first teach. When the ladle is held in the usual method, the labour of throwing the liquor to the described height would be consi- derable: but it becomes uncommonly easy when the hook of a slender pendulous chain or rope is made to sling the handle of the ladle at a spur, marking the proper centre of motion, or the fulcrum ‘on which the ladle is to play, with little effort to the workman. At skipping-time the instrument reserves some filtered syrup to recruit the emptied teach: this is the business of a few a On the Manufacture of Muscovado Sugar. 319 few minutes: if it were as many hours, such syrup would take no damage in the time. ft About twelve ladlings forward belong to a skip; and for each of these its share of reserved temper is to be used. Less than a tea-spoonful generally serves: a small excess does no harm now to the coleur of the sugar: both the filth and the temper are stopped in the filter; and the sugar becomes im- proved in the manner above described, provided no part of it be over-heated in the skipping. The damage which the liquid sugar takes here is certainly greater, as it is fouler by the herbaceous matter; because the herbaceous matter becomes darkened or charred sooner than the mere sugar. But whether the filter be used or not, there will always be some depravation of the colour of the - ground sugar when the skipping is conducted in the usual manner. Of the Spraying Instrument in Skipping. Tt is now sufficiently understood, that in beiling down and in Jadling forward, great care ought to be taken that no part of a vessel, between the surface of the charge and the under-pinning, shall be so far heated as to burn-to the syrup or sugar adhering to it; and that this burning or charring is to be prevented by one negro rolling the residuary liquor up to the under-pinning, until another has ladled forward and charged the evacuated teach, and until the liquor froths to the under-pinning. But as nothing of this kind is practicable in the skipping from the first teach, some new expedient is necessary to pre- vent the burning-to which is manifested in every whole skip, by the hissing heat of the copper, by the empyreu- matic smell, and by the film of charred matter which washes from the sides into the subsequent charge of liquor; for the practice of some, in skipping only one-half of the ready and graining charge, is a very objectionable shift. To preserve the crop and grain once attained, to prevent all empyreuma, and to maintain every advantage of the fil- tration, I have contrived, and presented in trial to the ho- nourable 320 On the Manufacture of Muscovado Sugar. nourable gentlemen of the committee, a simple instrument, which the negroes have since used with the greatest ease. It is nothing more than a tube of tinned iron-or shect copper, about six feet and a half in Jength, with a bore of ~ one-half or three-fourths of an inch in diameter, delivering a spray of water on the bottoin and sides of the skipping- teach during the short time of skipping, and covling it suf- ficiently and equally with a very small quantity of water. Upon the common shed or arched covering which shelters . the stoker, a cask of water is placed, and a slender hose or Jeathern tube inserted in the cask, delivers the high column of water into the metallic tube through a small stop-cock ; and the other end of the metallic File being provided spit six small holes, like those in the top of a pepper-box, and looking upwards when the tube is held horizontal, the water is squirted in the form of spray by the heavy pressure of the high column to the extent of the bottom and sides of the teach only, and the spray ceases when the cock is closed. The direction of the spray requires no skill of the negro ; for a spur on the tinned iron tube stops it at the proper place; and he has only to hold the tube straight forward, while he grasps it near the spur and near the mouth-piece of the fire-place with one hand, and holds or turns the cock with the other. \ The fire is not disturbed, and no wet trash is allowed to chill the furnace and clot upon the grating. The spray eva- porates as it touches and cools the teach; and as the fire- face of the furnace remains untouched and red hot, the fresh charge boils in the first teach in half a minute after the spray is stopped, and the instrument now shut at the cock 1s with- drawn. The advantage of this instrument is not confined to the prevention of empyreuma and colour; for it serves to make all the portions of the skipped mass equal in spissitude, or, as the workmen say, equally boiled, and enables the work- man to defer the skipping until the proof ts perfectly deci- sive; and these purposes are answered at the expenditure of two or three quarts of water. a Subservience On the Manufacture of Muscovado Sugar. = 321 Subservience of these Measures to the Improvement of Rum. Concerning rum it is now to be observed, that it derives the depreciating characters of the recent spirit from twe sources; the chief of which is the filth of the scums, and especially the first scums in yawing. The tendency of such matter, even if there were nothing yerminous or animalcular in it, is to the putrefactive fer- mentation, or rotting, while that of the sweet is to the vinous fermentation, and thence to the acetous 5 the product of the former fermentation is as offensive to the smell and taste, and as noxious, as that of the latter ts grateful and cordial. Wherever scums are detained to await the spontaneous s¢- é paration of the sweets from the filth, an intestine motion may be observed, and then chiefly in the concurrence of these fermentations the offensive product is generated ; the rest is formed in the fermenting vats, in quantity proportionate to the filth of this kind which passes into them. Every vinous liquor capable of yielding an intoxicating spirit by distillation, affords.some quantity of peculiar essen- tial oil, which awaits the arise of the water of the latter and weaker runnings, and characterizes them ; therefore this es- sential oil is, in a great measure, separable from the spirit by redistillation ; especially if salts retentive of the water, and restraining the volatility of the oil, aré used. But it is peculiar to the ordinary manufacture of rum that very offensive ethereal fluid is generated in these mixed fer- mentations, and that by reason of its volatility it is insepa- rable by a redistillation. But from the source above mentioned the essential oil of rum acquires extraordinary nauseousness ; and as a single re- distillation cannot exclude it totally, and as any number could not exclude the ethereal taint above mentioned, the best new rum of any estate is that which runs intermediate in respect of the offensive ether and the fetid oily feints. , All rum is improved by time in wooden casks, by exhala- tion of ether and absorption of oil, and under a growing charge for waste and for interest on the price. Some have improved it sooner by ventilation, but not without a great Vol. 24. No. 96. May 1806. XX waste $23 On the Density of froxen Mercury. waste of spirits ; but now it may be remarkably improved immediately by measures which prevent the above conta- mination ; and the first of these is the abstraction of the pultrefactive mattet by filtration; and-the immediate con- veyance of the clear warm fragrant liquor to the working cistern, there to undergo the most timely and productive fermentation, atid to suffer the least defalcation of spirit by foal scum and bottoms, which are generally thrown away. Another source of the contamination is in the empy- reuma ; but as this regards the distillation as well as the er- rors in byte sugar, it is unnecessary to say more of it at present than that the prescribed measures, together with a judicious setting and management of the still, will totally prevent the empyreumatic smell and taste. LVII. Letter of M.Tarpy pre La Brossy to Professor PicreT, of Geneva, upon the Experiments of Mr. Biv- DLE, relative to the Density of frozen Mercury *. Joyeuse (Ardéche}, SIR, Oct. 13, 1805. Tue experiments of Mr. Biddle (vol. xxxix. p. 2174), in order to determine the density of solid mercury, having at- tracted my attention, I cannot pass over in silence the se- rious objections to which the results of the above gentleman are liable. In communicating them to you, I am well per- suaded that I shall enter completely into your views, which have equally for their objects the extension of truth and the removal of error. Mr. Biddle, after having made known the process which he followed and the precautions taken by him, informs us, that a thousand grains of mercury made solid at the 40th degree below the zero of Fahrenheit (— 32 of Reaumur), experienced, when weighed in alcohol of the same tempe- rature, a loss in weight of 59°8 grains. A thousand grains of pure silver, weighed by the same * From Billiotheque Britannique, vol. xxx. + Vide Nicholson's Journal for April 1805. cas Rie oy ‘balance, On the Density of froxen Mercury. 323 balance, in the same alcohol, and at the same temperature, lost §8°305 grains of their weight. Upon this, Mr. Biddle, regarding the loss of weight of the mercury and silver as in an inverse ratio to the specific weights of these metallic sub- stances, and having found that that of sily er, with the same balance and in distilled water, was 10°436, he multiplied this sum by 8§°105, and divided the product by 59-8, which gave him 15°612 for the specific weight of the mercury in a solid state. - But the same hydrostatic balance isa eiven the num - ber 13°545 for the specific gravity of the same mercury in — liquid state, the thermometer being at + 47° Fahr. (+ 2° Reau.), it would seem that nothiug remains but to con- ae! with the author, ‘¢ that the volume of solid mercury - is less by about one-seventh of what it is in the liquid state.” But are all the principles of these calculations faultless ? Are none of these weights evidently wrong? I shall not make a gratuitous supposition ; I shall judge by facts alone. The antient tables of specific gravities give 0°806 for that of alcohol or rectified spirit of wine. It is at about 0°820, in the temperature of 19° of Reaumur (+ 543° Fahr.), ac- cording to M. Bories, of Marseilles, at which the operations on these substances can be regarded as decisive authority. We then fairly value it 0°510, without encroaching much upon truth. But the liquid mereury, which, according to its specific gravity of 13°545, loses in distilled water 73-828 grains in the thousand, ought to lose 59°8 in alcohol at the weight of 0°310; and in this manner the great difference disappears which Mr. Biddle thought himself entitled to mark between the density of liquid and solid mercury. Pure silver, which in consequence of a specific gravity of 10°436 ought to lose in distilled water 95°822 grains in the 1000, would lose no more than 77°615 in alcohol at 0°810, - which is very different from §8°105. To account for this difference, we cannot allege the greater density of the al- cohol at the temperature i — 47° Fabr., because that could not contribute more than tiwo or three grains at most to the loss of the weight of the silver: we should not be better founded in supposing that the alcoho] employed happening X 2 to 394 On the Oxide of Manganese of Naygag. to be of an inferior quality, its specific gravity was greater, because upon this supposition, and in order to make the loss of weight in the silver amount to 88°105 grains, the spe< cific gravity of this alcohol, compared with that of water, must have been 0°920. But Mr. Biddle could not but be mistaken with such a liquor, which was nothing more than the most common spirits, and which, if I am not mistaken, could not support the temperature of the experiment without freezing. It appears, therefore, ascertained, that there is an error in the weights; and consequently we may conceive that, the density of the solid mercury having been deduced from the comparison of the results of these weights, the density has been found so much the greater as the loss of the weight in silver had been expressed by too large a number. I have no intention to pre-judge the question relative to the density of solid mercury: I am far from wishing to raise doubts upon the talents of Mr. Biddle, or upon the | penetra- tion of the members of the Philosophical Society of Birming- ham, in whose presence and to. whose satisfaction the ex- periments of the former were made; but I think myself en- titled to say, that the experiments, of which he has published the results, ought at least to be made over again. Mr. Bid- dle’s idea is a happy one, and I do not deny that these ex- periments may lead to the solution of the problem. I have the honour to be, &c. Tarpy be La Brossy. LVIII.. Analysis of the sulphuretted Oxide of Manganese of Naygag. By M. VauauEtin*. M. Kiaprotu, having made an analysis of the sulphuret of manganese under the name of siebenburghischen, disco- vered that it is composed of 82 parts of oxide of manganese at the minimum, or soluble in nitric acid; of five parts of carbonic acid, and of eleven parts of sulphur, without * From Annales du Muséum d'Histoire Naturelle, vol. vi. haying On the Oxide of Manganese of Naygag. 325 having discovered either gold or silver in it, as asserted by M. Muller, of Re'chenstein. ° The celebrated Berlin chemist having thus enriched mi- neralogy with a new species of the manganese genus, which down to the present time had existed only in one form, that of oxidated manganese, he has also thereby enriched che- mistry with a new fact concerning the action of the nitric acid upon sulphurets, for the decomposition of which it is usually employed, with the view of dissolving the metallic oxide combined with sulphur, without touching the latter. As soon as M. Haiiy recognized this mineral in his col- lection, he sent us a specimen in order that we might sub- mit it to analysis. M. Proust also analysed this mineral almost at the same moment with M, Klaproth. The former observed the same phenomena, but for want of a large enough quantity he was not able to determine the state in which manganese is when combined with sulphur, nor the respective quantities of these bodies. The sulphuret of manganese of naygag is accompanied with manganeseous carbonated lime: it has for a matrix a white hyaline quartz: its specific gravity is 4: its texture is lamellous, with a metallic lustre, when the surface has not been long exposed to the air. Reduced into powder, it is of an olive green colour: it loses nothing by heat. Five grammes of this mineral, perfectly freed from its matrix, were reduced to a very fine powder and treated with weak nitric acid; which immediately exercised a lively action upon it, accompanied with a disengagement of sulphuretted hydrogengas. We gathered a certain quantity of this gas, in order to examine its nature. The mixture was slightly heated, and a new portion of the nitric acid was introduced until effervescence ceased: the liquor was then filtered, which was a little reddish, but became colourless upon the addition of water. The residue weighed a decigramme. It was com- posed of blackish brown flakes, which, upon being exposed to flame with the blowpipe, took fire like sulphur, spread a slight arsenical smell, and left a substance which did not colour borax like manganese, but like iron. X 3 The 326 On the Oxide of Manganese of Naygug. The gas obtained in this experiment, when passed through lime‘water, did not injure its transparency, but gave it the- property of blackening solutions of lead. The nitric solution was mixed with carbonate of potash : it formed an abundant white precipitate with a brisk disen- gagement of carbonic acid gas. We heated it lightly m order to drive off the excess of this acid ; and we separated the precipitate, which, upon being well araaield and dried, weighed 73 grammes. The difference between our results and those of M. Klaproth seems to arise from the manga- nese used by us having been very pure, while that einployed by M. Klaproth probably contained carbonate of lime. M. Klaproth endeavoured’ to form a combination between: sulphur and the oxide of manganese at the minimum, in order to make comparative experiments, and he discovered that the artificial sulphuret of manganese, when no atom of sulphuretted hydrogen could enter into it, had the same cha- racters as the natural sulphuret. In order to follow his ex- periments, [ calcined in a retort, the aperture of which com~ municated with a balloon filled with lime water, 7-4 grammes of carbonate of manganese obtained by precipitation by means of carbonate of patash, The carbonic acid gas began to disengage itself before the retort was red, and at the end of a quarter of an hour’s cal- cination the disengagement ceased. The oxide contained in the retort was slightly coloured, at least at its surface. We introduced into the retort, while yet warm, two grammes of flowers of sulphur, and we agitated it in order to: produce a mixture; the-mass melted, and a considerable quantity of sulphur was sublimed. As soon as the sublimation of the sulphur ceased, the mass, when taken ont of the retort while warm, took fire on exposure to the air in the manner of pyrophorus. It was green, like the natural sulphuret in powder ; and it weighed 5-9 orammes. This artificial sul- phuret dissolved in weak nitric acid with effervescence and a disengagement of sulphuretted hydrogen gas; but it leaves more sulpbur as a residue than natural sulphuret. The following is the manner in which M. Klaproth ex- plains the disengagement of the hydrogen gas which takes place On-the Oxide of Manganese of Naygag. 327 place during the solution of manganese in the nitric acid. {n spite of the disengagement, says he, of a considerable enough quantity of sulphuretted hydrogen gas during the _ Solution of this mineral, it appears to me that it would be an error to believe that this gas exists ready formed in the mineral or in any of those which yield it by the humid way, and to regard it as one of their constituent parts. There is no doubt that it is formed by the decomposition of water, since by calcination we obtain nothing else but carbonic acid gas. By synthesis, the probability that no hydrogen enters into the combination of sulphur with the oxide of manganese acquires still more force; and yet this combina- tion yields sulphuretted hydrogen gas with the acids. ‘In order to know if the nitric acid is not decomposed during the solution of sulphuret of manganese, as happens with almost all the metals which havea great affinity for oxygen, or, if water alone, by yielding its oxygen to one of the elements of this mineral, does not give birth to this hydro- gen gas, we dissolved a certain quantity of sulphurettedman- ganese in weak nitric acid; we concentrated the solution, and distilled it in a retort with caustic potash: but the pro- duce not having given any sign of the presence of ammonia, we concluded from this that the nitric acid 1s not decomposed in this operation. In order to have the just quantity of oxide of manganese at the mipimum, we calcined in a retort:7°4 grammes of carbonate of this metal prepared fron: a solution of five grammes, and we obtained an oxide almost white, which, weighed while warm, yielded 4°25 grammes, which was at the rate of 85 in the hundred. Let us actually admit a loss of two parts: we shall then have 13 parts of sulphur; and as the loss can scarcely be any thing else than sulphur, the quantities will stand thus : Manganese at the mimimum - 85 Sulphur - - - - 15 a 100* * There is also in this mineral a small quantity of iron and arsenic, which has been discovered among the sulphur which remains after its solution in weak nitric acid; but these substances appear to be accidental. X4 Reflections, 328 On the Oxide of Manganese of Naygeg. * — Reflections. M. Klaproth justly regards the manganese in the mineral of which we are speaking as oxidated at the minimum, and he has recourse at the same time to the decomposition of water in order to explain the disengagement of sulphuretted hydrogen gas which takes place during the solution of the mineral in the acids; but this philosopher neither tells us how or wherefore water is decomposed in this operation. The manganese cannot be the cause of it, since it is already united to oxygen, and because it is discovered in the acids which have dissolved it in the same state in which it existed in the fossil, that is to say, at the minimum. The water, then, could not have been decomposed but by the sulphur. But how can we comprehend this effect while the nitric acid is present? If, however, it is the sulphur which decomposes the water, and which gives birth to the sulphuretted hydro- gen, I should have found sulphuric acid in the nitric solution of the mineral. In order to ascertain it, I dissolved in the eold a certain quantity of the same sulphuret of manganese in weak nitric acid, in order that it might not burn the sul- phur. The phenomena were the same as before; and the filtered solution gave, in fact, by means of the muriate of barytes, a precipitate which was a true sulphate of that base. This experiment, then, seemed to demonstrate, that sul- phur united to oxide of manganese has the power of decom- posing water by combining with its oxygen, and thus sets its hydrogen at liberty, which unites with another portion of sulphur. This fact is the more worthy of the attention of chemists, that, to my knowledge, this is the first time that it has been observed, and that in every case where me- tallic sulphurets or sulphuretted oxides have been decom+ posed by the strong or weak nitric acid, it has been always the latter which has been decomposed, and nitrous gas, or modifications of it, constantly obtained, and never sulphu- retted hydrogen gas: this is quite conformable to the laws of chemical affinity. It is true, that there are metals which decompose water at the same time with nitric acid; but hydrogen never makes its appearance: it unites with the azote of the nitric acid and forms ammonia, The On the Eremophilus and Astroblepus. 329 The sulphuretted oxide of manganese thus forms an ex- ception to the rule hitherto observed, if we do not admit hydrogen into this substance as one of its constituent parts. LIX. Memoir on the Eremophilus and Astroblepus, two new Genera of the Order of Apodes. By M. DE HumBo.ipt*. W azn we ascend the chain of the Andes to the height of 2600 toises (166612 English feet)’ and upwards, great Jevel plains and lakes of a considerable extent are seen. It is singular to observe, that, while the soil 1s still covered with a beautiful vegetation, the woods filled with quadru- peds, and the air with a great variety of birds, the water alone, the Jakes and the rivers, are so little inhabited. The cause of this phenomenon relates, without doubt, to geo~- logical facts ; it pertains to the grand mystery of the origin and migration of species. The considerable Jakes which surround the city of Mex- ico, at the height of 1160 toises +, nourish but two species of fish, of which one, the axalotl, belongs rather to the genera szrenus and proteus. M. Cuvier, to whom we brought this extraordinarily organized animal, unknown in Europe, is engaged with its anatomy, which he will shortly publish. In the kingdom of New Granada, in the beautiful valley of Bogota, about 1347 toises high, there also exist but two species, which the inhabitants of that country call capitan and guapucha. The one is an atherine, and the other a new genus of apodes, that I am about to describe in this memoir. The form of its tail and its anal fin distinguish it sufficiently from the genus ¢richiurus, which 1s also found in the fresh waters of South America. I have designed this non-descript fish at the place; and Messrs. Lacepede and Cuvier, who have willingly examined my descriptions, like me, consider it a new genus well characterized. 1 have named it eremo- philus on accout of the solitude in which it lives at so great * From Recucil d’Olservations de Zoologie et d Anatomie compare, ire livraison. Communicated by a correspoudent.? + The French toise is about six fect four inches nine-tenths English. an 330 On the Eremophilus and Astroblepus, ‘an cleyation, and in waters which are inhabited by almost no other living being, The naturalists, who fear that new species of the same genys may be discovered. in very different situations, may change the name of eremophilus into that of thrichomycterus, taken from the barbillons or whiskers at- tached to the nose of this fish. EREMOPHILUS. (See Plate VIII.) Apop. Cuaracter GENERICUS ESSENTIALIS. Corpus elongatum. Cirri maxillares 4, nasales semituly- lost 2. Pinna dorsalis et analis. Membreng lranchio- stega radtis \—2. | E. Morisi. Corpore elongato, plumbeo, ceerulescenti, maculis dadaleis olivaceis variegata; operculi. branchiostegi, duplicatura spineloso-serrata. The body of the captain of Bogota is long, and has some analogy with that of the eel. Itis compressed, of a blueish gray colour, and spotted with olive green. These spots, the outline of which forms very striking sinuosities, assume in some individuals a yellawish tint. The head is little and flat. The mouth, situated at the extremity of the nose, ig straight. The upper jaw projects over the under one; the first, very long and double, is furnished with six fleshy bar- billons or whiskers, of which the two exteryiar are the long- est. Two other barbillons, shorter and semi-tubulous, are placed on the nostrils. It has very little eyes, which are veiled by a semi-transparent membrane, like the gymnotes and lampreys. The extremity of its lips is furnished with httle teeth resembling hatrs, The tongue is very fleshy, but short. The operculum or uvula forms a very narrow branchial opening, and it is very difficult to distinguish its folds (lames), In the most part of the individuals which I have examined, it appears to me that the captain, similar to the cyclopterus dentex and a few other fishes, has but two radii or furrows, which are as if soldered the one on the other. The edge of the operculum or uvula is indented. The dorsal fin has eight radii, the pectoral six, that of the anus six, and that of the tail, which is round, twelve radii: it \ On the Eremophilus and Astroblepus. 332 it has no swim or air-bladder. ‘The length of this fish is from 10 to 11 inches, and its body is covered with a mucus common to the greater part of the apodes. It inhabits the little river of Bogota, that forms the famous cataract of Te- quendama. The captain is a very agreeable aliment, and so much the more precjous, that without it the inhabitants of the capital of Santa Fé, in the time of Lent, would be re- duced to the use of only salted sea-fish brought from a great distance. J have viven this species the trivial name Awtisii in honour of the celebrated naturalist, whose rich callec- tions are preserved in the great valley of Bogota. - The little river of Palacé, near Popayan, nourishes another fish, which, by its mucosity and the position of its fins, has’ some relation with the eremophilus, but which ought also to coustitute a new genus of apedes. The breadth of its head is greater_than that of the body; its eyes placed on the upper part of the head, and turned so that the pupils are directed, like as in the wranoscopus mus, towards the surface of the water; the indenting of the first radu of the fins, the branchial membrane of four radii; the tongue; the want of barbillons or whiskers on the nostrils ; and the dorsal fin, which approaches more to the head than the tail; suffi- eiently distinguish the pescado negro (black fish) of Popayan from the capitan of Santa Fé, I have given the name of ° astrollepus to this genus, in allusion to the extraordinary’ situation of its eyes. ASTROBLEPUS. (Sce Plate VIII.) Aprop. CuaRACTER GENERICUS EsSENTIALIS, Corpus plegioplateum. Membrana branchiostega radiis 4, Oculi verficales. Cirri 2 maxillares, nasales nulli. A. GRIXALVII. Corpore ex olivaceo nigrescenti, capite subtruncato, radiis pinnarum exterioribus serratis. — Corpus plagioplateum, oblon gum, nudum, olivaceo-nigres— cens, caudam yersus angustatum, subcompressum. Caput obtusum, magnum, subtruncatum. Cirri 2, apice recurvi et sublati, ricto in labio superiori adnati. Maxilla labiata, Jabio superior’ majori plicatili. Lingua nulla. Nares 2 magna, 332 On the Eremophilus and Astroblepus. magne, margine membranaceo. Oculi verticales, minuti. Operculum simplex, convexum, nudum. Membrana bran- chiostega radiis 4, ossiculo anteriori subserrato. Pinna pec- toralis radiis 10. Pinna analis radtis 7. Pinna caudalis integra radiis 12; radiis duobus exterioribus (ut omnium pinnarum) extrorsum serratis. Longitudo 14 pollicaris. I have given this fish the specific name Grixaluw* to perpetuate the memory of a respectable philosopher, Don Mariano Grixalva, who has disseminated at Popayan a taste for the physical sciences, which he himself cultivated with success. The pescado negro, so much eaten at Popayan, is found but in that part of the river Cauca which is most contiguous to the city. The physical cause of this phenomenon is suf- ficiently striking. From the volcano of Purasé descends a rivulet impregnated with sulphuric acid, that the inhabitants call Rio Vinagre (Vinegar River) ; it is known by the beau- tiful cascade which it forms at the foot of the volcano. From the point where the waters of Vinegar River unite with those of Cauca until four leagues lower down the latter is without fish, although in the upper part they are plentiful enough. The sniall quantities of acid that might escape our chemical analysis are often sufficiently great to injure the organiza~ tion of fishes. * Mutisti and Griralvzt are doubtless very scientifi¢ names. Linnzus, to gratify his puerile vanity, introduced the custom of giving arbitrary unmean- ing names of men to plants: Werner embraced the same unphilosophical system of pitiable ambition in baptizing minerals (some wits have asserted, indeed, that such is his attachment to water, that he actually performed the ceremony of sprinkling certain stones, giving them at the same time the fa- vourite name of some of his followers): and M. Humboldt now transfers men’s names to the very opposite abodes of fire and water, in his volcanic fish! All the labours of these men have done much lessto disseminate a taste for the natural sciences, than the introduction of such an absurd practice has effected in obstructing the advancement of real knowledge and true philoso- phy. Posterity, so far from venerating euch names, will execrate the being, who, to conceal his real ignorance by the assumption of universal knowledge, could thus deliberately bury true science and much accurate knowledge under the ruins of a Babylonish jargon! Peace to the manes of Lavoisier: although he himself made no real discoveries, yet the philosophical use which he made of those of the English and other philosophers will not speedily be forgotten by succeeding generations.—Translator. LX. Me- [ 333°] LX. \ Memoir on a new Species of Pimelodus thrown out of the Volcanoes in the Kingdom of Quito; with some Particulars respecting the Volcanoes of the Andes. By M. De Humsoupr*, (i chain of the Andes, from the Straits of Magellan to the northern shores bordering on Asia, extending over more than 2000 leagues, presents above fifty volcanoes still active, of which the phenomena are as various as their height and Jocal situation. A small number of the least elevated of these volcanoes throw out running Java. I have seen, at the volcano of Zurnllo, in Mexico, a basaltic cone that sprung from the earth the 15th September 1759, and at present rising 249 toises (1595% feet) above the surrounding plain. The voleanic ridges of Guatimala cast out a prodi- gious quantity of muriate of ammonia. Those of Popayan and the high plain of Pasto present either solfatares, which exhale sulphureous acid, or little craters filled with boiling water, and disengaging sulphurated hydrogen, which de- composes by contact with the oxygen of the atmosphere. The volcanoes of the kingdom of Quito throw out pumice- stone, basaltest, and scorified porphyries ; and vomit enor- mous quantities of water, carburetted argil, and muddy mat- ter, which spreads fertility from eight to ten leagues around. But, since the period to which the traditions of the natives ascend, they have never produced great masses of running melted lava. The height of these colossal mountains, that surpasses five times that of Vesuvius, and their inland situa- tion, are, without doubt, the principal causes of these ano- malies. The subterranean noise of Cotopaxi, at the time of its great explosions, extends to distances equal to that from Vesuvius to Dijon. But, notwithstanding this inten- % From Recucil d’Olservations de Zoologie et d’ Anatomie comparé, ire livratsor. + It would have been of some use to geology had the author here men- tioned whether the stone which he calls basaltes has been submitted to the action of fire or water; or whether, in addition to the other well known characters of this mineral, it yielded hydrogen gas on distillation, the latter being the peculiar characteristic of what is properly denominated basaltes.— Traaslator. “os 334 On a new Species of Pimelodus. sity of force, it is known, that if the volcanic fire was at a great depth, the melted lava could neither raise itself to the edge of the crater, nor pierce the flank of these mountains, which to the height of 1400 toises (8971+ feet) are fortified by high surrounding plains. It appears, therefore, natural, that volcanoes so elevated should discharge from their mouth but isolated stones, volcanic cinders or ashes, flames, boil- ing water, and, above all, this carburetted argil impregnated with sulphur, that is called moya* in the language of the country. The mountains of the kingdom of Quito occasionally offer another spectacle, less alarming, but, not less curious to the naturalist. The great explosions are periodical, and some- what rare. Cotopaxi, Tungurahua, and Sangay, some- times do not present one ih twenty or-thirty years. But during such intervals even these volcanoes will discharge enormous quantities of argillacecous mud ; and, what is more extraordinary, an innumerable quantity of fish. By acct- dent, none of these volcanic inundations took place the year that I passed the Andes of Quito; but the fish vomited from the volcanoes is a phenomenon so common, and so gene- ‘rally known by all the mhabiiants of that country, that there cannot remain the least doubt of its authenticity. As there ‘are in these regions several very well informed persons, who have successfully devoted themsclves to the physical sciences, Thavehadanvpportunity of procuring exact information (rer seignemens) respecting these fishes. M. de Larrea, at Ouito, well versed in the study of chemistry, who has formed a ‘cabinet of the minerals of his country, has been, above all others, the most useful to me in these researches. Exa- mining the archives of several little towns in the neighbour- hood of Cotopaxi, in order to extract the epochs of the great earthquakes, that fortunately have been preserved with care, I there found some notes on the fish ejected from the vol- * M. Humboldt seems not to have been aware that this name has been affixed to it in consequence of its having some resemblance to a kind of blackish coarse bread made of grits or pollard, and used in Spain by some very poor but proud people, or for purposes of penitence in cascs of a pecado mortal.—Translator. canoes. On a new Species of Pimelodus. 835° fanoes. On the estates of the marquis of Selvalegre the Cotopaxi had thrown a quantity so great, that their putre- faction spread a fetid odour around. In 1691 the almost _ extinguished volcano of Imbaburu threw out thousands on the fields in the environs of the city of Ibarra. The putrid fevers which commenced at that period were atuributed to the miasma which exhaled from these fish, heaped on the sur+ face of the earth and exposed to the rays of the sun. The last time that Imbaburu ejected fish was on the 19th of June 1698, when the volcano of Cargneirazo sunk, and thousands of these animals enveloped in argillaceous mud were thrown over the crumbling borders; The Cotopaxi and Tungurahua throw out fish, sometimes by thecrater which isat the top of these mountains, sometimes by lateral vents, but constantly at 2500 or 2600 toises above the level of the sea: the adjacent plains being 1300 toises high; one may conclude that these animals issue from a point whith is 1300 toises more elevated than the plains on which they are thrown. Some Indians have assured me that the fish vomited by the volcanoes were sometimes still living in descending along the flank of the mountain: but this fact does not appear to me sufliciently proved : certain it is, that among the thousands of dead fish that in a few hours - are seen descending from Cotopaxi with great bodies of cold fresh water, there are very few that are so much disfigured that one can believe them to have been exposed to the action of a strong heat. This fact becomes still more striking when we consider the soft flesh of these animals, and the thick smoke which the volcano exhales during theeruption. It ap- peared to me of very great importance to descriptive natural history to verify sufficiently the nature of these animals. All the inhabitants agree that they are identical with those which are found in the rivulets at the foot of these volcanoes, and called prennadillas*: they are even the only species of fish that is discovered at the height of above 1400 toises * This word is an indifferent or contemptuous diminutive, indicating abun- dant, pregnant, fruitful, easily taken, but not a pleasing or desirable object. The name is purely Spanish and net Indian, of course could never have been npplied to any fish used as food, by Spaniards.—Translator. 1c in 336 On a new Species of Pimelodus. in the waters of the kingdom of Quito. I have designed it, with care, on the spot, and my design has been coloured by M. Turpin. I have observed that the prennadilla is a new species of the genus silurus. M. Lacepede, who has also examined it, advised me to place it in that division of stdurus which, in the fifth volume of his Natural History of Fishes, he has described under the name of pimelodes. This new species of pimelodus has a depressed body of an olive colour mixed with little black spots. The mouth, which is at the extremity of the nose, is very large, and furnished with two barbillons or whiskers attached to the jaws. The nostrils are tubulous ; the eyes are very small, and placed towards the middle of the head. The skin of the body and the tail is covered with an abundant mucus, and the mouth is furnished with very small teeth. The branchial membrane has four radii, like the pimelodus chilensis ; the pectoral fin has nine; the ventral five; the first dorsal six; the fin of the anus seven; and that of the tail, which is bifid, has twelve radii. The first radius of all the fins is indented on the out- side: the second dorsal fin is adipose, and placed near the tail. This little pimelodus, which is found in lakes even to the height of 1700 toises, is, without doubt, the fish that lives in the most elevated regions of our globe. Its common length scarcely amounts to ten centimetres (four inches) ; but there are varieties which do not appear to reach five cen- timetres (two inches) in length. In the system of ichthyology this new species of pimelodus should be ranged in the first sub-genus established by Lace- pede, among the forked-tailed pimelodes. It must be in the first species, before the pimelodus bagre. As it is the only one of that division that has but two whiskers, I give it the naine of PIMELODUS Cyctropum. (Plate VIII.) Cirris duobus, corpore olivaceo nigro-punctato. This little fish lives in rivulets at the temperature of 10° — of the centigrade thermometer, while other species of the same genus exist in rivers in the plains the water of which is at 27°. The pimelodus is but very rarely eaten, and then | 4 only = On a new Species of Pimelodus. 337 only by the most indigent race of Indians; its aspect and the sliminess of its skin render it very disgusting. j From the enormous quantity of pimelodes that the vol- canoes of the kingdom of Quito occasionally discharge, one cannot doubt that country contains great subterranean lakes which conceal these fishes ; for: the individuals that exist in the little. rivers around are very few in number. A part of those rivers may communicate with the subterra- nean pits: it is also probable that the first pimelodes which have inhabited these pits have mounted there against the current. Ihave seen fish in the caverns of Derbyshire, in England; and near Gailenreuth, in Germany, where the fossil heads of bears and lions are found, there are living trouts in the grottoes, which at present are very distant from. any rivulet, and greatly elevated above the level of the neigh- bouring waters. In the province of Quito, the subterraneous roarings that-accompany the earthquakes ; ; the masses of rocks that we think we hear crumbling down below the earth we walk on; the immense quantity of water that issues from the earth in the driest places during the volcanic explosions ; and numerous other phenomena, indicate that all the soil of this elevated plain is undermined. But, if it is easy to conceive that vast subterranean basins may be filled with water which nourishes fishes, it is more difficult to ex- plain how these animals are attracted by volcanoes that ascend to the height of 1300 toises, and discharged either by their craters or by their lateral vents. Should we sup- pose that the pimelodes exist in subterranean basins of the same height at which they are seen to issue? How conceive their origin in a position so extraordinary ; in the flank of a cone so often heated, and perhaps partly produced by vol- eanie fire? Whatever may be the source from which the issue, the perfect state in whieh they are found induces us to believe that those volcanoes, the most elevated and the most active in the world, experience, from time to time, con- vulsive movements, during which the disengagement of ca- ' Joric appears less considerable than we should suppose it. Earthquakes do not always accompany those phenomena. Perhaps, in the different concamerations that may be ad- Vol. 24. No. 96. May 1806. ¥ mitted 338 _ Ona new Species of Pimelodus: mitted in the interior of a volcano, the air is found o¢ca- sionally condensed, and that it is this condensed air which contributes to raise the water and fish; perhaps they issue from a concavity distant from those which emit volcanic fire ; possibly, in fine, the argillaceous mud in which those animals are enveloped defends them from the action of great heat. Notwithstanding all the researches that have been re- cently made on volcanoes, there is nothing but the study of volcanic productions that has made any progress. As to the nature of the combustibles which nourish those sub- terranean fires, and the mode of action of those fires them- selves, I believe that all persons who have visited the bor- ders of craters, and who have lived a long time in the vici- nity of volcanoes, will sincerely avow, with mie, that we are still very far from being able to give an explication, which, without being contrary to the principles of chemistry and of physics, could account for the great phenomena which vyol- canic explosions present. The corregidor of the city of Ibarra, don José Pose Pardo, has communicated to me an interesting observation on the pimelodes. ¢* It is known (says he, in a letter which I have still preserved,) that the volcano of Imbaburu, at the time of its great eruption on the side next our city, threw out an enormous quantity of prennadillas z it even continues still occasionally to do so, especially after great rains. It is ob- served that these fishes actually live in the interior of the mountain, and that the Indians of S. Pabla fish* for them in a rivulet at the very place whence they issue from the rock. This fishery does not succeed either in the day or in moonlight: a very dark night is therefore necessary, as the prennadillas will not otherwise come out of the volcano, the interior of which is hollow.” It appears, then, that the light is injurious to those subterranean fishes, which are not * This is an assertion somewhat contrary to that of their being very bad food, and disagreeable in appearance. It is within the particular knowledge ef the translator, that the Spaniards of South America are both very scep- tical and very witty, and that to play upon the philosophical faith of Eu- ropeans would be their highest delight. He ntust therefore be pardoned for regarding the letter of el Senor Corregidor as a jeu d’esprit en revanche for the sarcastic observations of French travellers on the Spaniards—Transtator. i l accustomed On a new Species of Monkey. 339 accustomed to so strong a stimulus: an observation so much the more curious, that the pimelodes of the same species, which inhabit the brooks in the vicinity of the city of Quito; live exposed to the brightness of the meridian sun. «us LXI. Memoir on a new Species of Monkey found in the eastern Declivity of the Andes. By M. pp HumBorpr*. Ix the vast plains which extend from the eastern declivity of the Andes towards the shores of the Brazils, in the thick forests on the Amazons, Rio Negro (Black River), and Oronoco, the cavia capylara, sus tajassu, and the monkeys, are the quadrupeds most common. The marmose and alou- ate prevail over all the others, whether for variety of species or number of individuals. Some of these monkeys, such as the capuchin of Oronoco, very different from the simia capucina Linn., the tiger-monkey or cusicusi, and the wi- dow, (three new species which I have discovered,) live in pairs, melancholy, maistrustful, flying (like man in a savage state) their proper species. Others, especially the sagouin and howling monkey, are seen in troops, from 80 to 100, springing from branch to branch in search of nourishment. The saimiri of Buffon, that are the tzfi of Atures (stmia sciurea), so esteemed on account of their gaiety, their mild- ness, and extreme littleness, assemble together when it be- gins torain. A fall of temperature of three or four degrees of the centigrade thermometer disturbs them so much, that they mutually embrace each other and form balls or knots, of which each individual seeks to occupy the middle, in order to find shelter. The Indian hunters, advertised by the cry of the titi, direct their arrows towards these flocks. Notwithstanding the great number of monkeys that na- turalists have described, it is probable that we are still ig- norant of the tenth part existing. In Africa, and even in South America, there are vast plains of twenty thousand * From Recueil d’Olservations de Zoologie et d’ Anatomic comparé, Ire livraison. Y2 square 340 On a new Species of Monkey: square leagues which have not yet been visited by any Eu- ropean. Qn the other hand, the monkeys the most com- mon ‘are still so impertectly represented even in the most recent works, executed with the greatest elegance, that those who have seen the living individuals world have difficulty to recognise them in the drawings published. Of this I might cite as examples the simia sciurea, varieties of the sma ca- pucina, and cven the simia paniscus, which is the game commonly eaten in the Upper Oronoco. Among the great number of new sapajous, or marmoses, that I had the opportunity of describing in my voyage to the aropics, I have chosen a monkey of the plains of Mocoa, remarkable for its resemblance with the lion of Africa, of which I made a drawing during my residence at Popayan. My sketch has been éepied and improved by M. we (Plate VIII.) The leoncito* is very rare, even in its native dnititry: It inhabits the plains which border on the eastern declivity of the Cordelliers, the fertile banks of the Putumayo and Ca- qucta: it never ascends even to the temperate regtons, while the wandering bands of the simia beelxelul sometimes push their excursions to heights equal to those of Canigou, and even Mont Perdu. The leoncito of Mocva, which I name simia leonina, differs essentially from all known species. It ~ has not the white head of the s. leucocephala figured in the work of Audebert. It differs from the s. rosalia, and the saki or fox-tailed monkey (s. pithecia), by a white spot which covers the top of the nose, the mouth, and the,chin; and from the s. zacchus of Brazil, by a tail without white rings, by its black visage, and by the disparity of conforma- tion that exists between the claws of its fore-feet and the nails on its hinder ones; the former almost resembling the claws of a cat, and the latter having nails like the human toes. The /eoncito is but seven or eight inches long, without counting the tail, which is of the length of the body. It is one of the least and most elegant monkeys that we have seen. It is gay and sportive, but, like most little * Leoncito, from leon (lion) a diminutive of endearment more common even with the Spaniards than the Italians.—Jranslator. animals, vA On a new Species of Monkey. 341 animals, very irascible. When it is vexed it bristles up the hair on its neck, that increases its resemblance to the Afri ican lion. I bave seen but two individuals of this very rare mon- key: they were the first that had been brought living to the west of the Cordellier. They were kept in a cage; and their movements were so rapid and so continual, that I had much difficulty to design them. Their hissing imitates the song of little birds, and I suppose that the conformation of their larynx (having a particular sac) is analogous to that which I have described in the simia ceedipus. I have been assured, that in the cottages of the Indians of Mocoa the leoncita breeds in the domestic state. By the way of Grand-Para and the river of Amazons they might be brought into Eu- rope. If a government, interested in the progress of de- scriptive natural history, would undertake an expedition in which that interest would not be rendered subservient to geographical discoveries ; if that government sent canoes or small boats to ascend the Oronoco, and to penetrate by the Casiquiaré and Rio Negro to the river of Amazons; in short, if, after having explored the mouths of the Caqueta and Putumayo, it would make these same boats descend to Grand-Para, it would in a little time unite collections the most precious to the study of zoology and botany. Such an expedition would be of little expense, and its success certain, . SIMJA LEONINA. Ex olivaceo fuscescens, facie atra, ore allo, dorso striis allo- ~flavescentibus notato. Caput parvum, depressum, nigrescens, Facies anthropo- morpha, atra; macula albo-ccerulescens circa os et nares, Auriculze subtriangulares djstantes, margine superior! de- flexo, magne, aterrimz, pilosie. Corpus ex badio oliva- ceum, pilis nigro-annulatis, in collo longioribus. Dorsum maculis et striis albo-flavescentibus variegatum. Cauda non prehensilis, longitudine corporis, superne atra, inferne badia, apice incurva et incrassata. Manus et pedes aterrimi, in- ferne nudi, pollice jn manibus anterioribus et posteriorbus distante. Ungues acuti, incuryi, atri; pollicis ungue in ma~ nibus anterioribus oblongo, acuto, in manibus posterioribus (pedibus) obtuso, anthropomorpho, ¥g LXII. Ana- {[ 342 ] LXII. Analysis of the Hot Springs at Bath. By Mr. Ricuarp Puituies, Member of the Askesian and of the British Mineralogical Societies *. Tue nature of the country round Bath, and other local circumstances, have been so fully described by those who have given chemical examinations of the waters of the hot springs at that place, that any further description appears unnecessary. As to the cause of the heat of these springs, we have so few data from which to reason, that I shall not offer even a conjecture on the subject. These waters have been frequently analysed. They have merited the attention they have received, not only from their early and extensive employment in the cure of diseases, but also on account of some peculiar changes to which they are subject. Of these the explanations have been so various as to show that they require still further examination. Of the sensible properties exhibited by these waters the most remarkable is their high temperature, the degree of which varies considerably at their different sources. At the hot bath it is 117°; at the king’s bath 114°; and at the cross ‘bath 109°. This statement does not exactly agree with what has been usually given. as their temperature. These results were obtained by pumping the water upon the bulb of a thermometer till the mercury ceased to rise. Their ~ taste is metallic, but not strongly or disagreeably so; this has not been universally allowed: but if they are drunk hot, this impression is readily distinguishable. Their specific gravity is 1-002 at each of the springs ; and as the effects produced by chemical tests are also perfectly similar, they may be considered as derived from one source, the temperature varying by their more or Jess circuitous pas- sage to the surface. For the purpose of analysis the water of “the king’s bath has been usually employed; and, although it does not appear to be a matter of much importance, I have followed the usual practice. * From the unpublished Transactions of the Askesian Society. Before Analysis of the Hot Springs at Bath. 343 Before the experiments made upon the water are related, it will be necessary to state those employed to ascertain the properties of the gas, which rises in great quantity through the water in the king’s bath. This gas is perfectly free from smell. (A) Some of the gas was received into a jar. A lighted taper put into it was immediately extinguished. (B) Received into lime water, it caused an immediate pre- cipitation. (C) Tincture of litmus suffered no change of colour by agitation with the gas. (D) The colour of dilute tincture of turmeric and infusion of galls was destroyed by it. From these’ effects the gas appears to consist principally of nitrogen gas with a small portion of carbonic acid gas. To ascertain the quantity of each, and whether any oxygen gas was present, the following experiments were performed ; ' (E) One hundred measures of the gas were strongly agi- tated with barytes water in a graduated tube. A considera- ble precipitate was deposited, and five measures were ab- sorbed. (F) One measure of nitrous gas was added to an equal quantity of the eas in an eudiometer in the water apparatus. The mixed gases underwent no alteration of colour or dimi- nution of volume. De (G) One hundred measures of the gas which had been deprived of carbonic acid by varytes water were submitted to the action of solution of green muriate of iron impregnated with nitrous gas. No absorption took place, boy This gas, therefore, consists of, Carbonic acid gas - = 00S Nitrogen gas - - = 5 1Q6 4 100 I now proceeded to try whether the water held either of these gases in solution. (H) Ten ounces of the water, which had been cooled in a well closed bottle, were put into a vessel furnished with a Y4 bent 344 Analysis of the Hot Springs at Bath. bent tube; the water was boiled for about twenty minutes, and the gas evolved from the water and the air of the tube, except a quantity too small to be estimated, were received in a graduated jar over mercury. Solution of potash ab-~ sorbed 3-4ths of an inch of this gas, which was carbonic acid. (I) The unabsorbed gas was transferred to the water appa- ratus, and tried in the usual way with nitrous gas. The mean result of comparative experiments upon it and atmo- spheric air showed that it was merely the air of the vessel, and that no nitrogen gas was held in solution by the water. As ten ounces of the water gave.*75 of an inch of car- bonic acid, one quart would furnish 2°4. This quantity is not quite exact, it being scarcely possible to obtain the whole of the carbonic acid by ebullition. Effects of Atmospheric Air and Re-agents. (K) Some of the water, while hot, having been exposed in a vessel of broad surface to the atmosphere, afforded in a few hours a small quantity of a white precipitate; but water . which had been cooled in a closed vessel remained perfectly transparent after several weeks exposure to the air. _ The re-agents added to the water while hot, and the ef- fects produced by them, were the following: (L) Acetate of lead,—a perfectly white precipitate. (M) Tincture of litmus,—no alteration of colour. (N) Tincture of turmeric,+no change indicating the pre- sence of uncombined alkali; its colour immediately almost destroyed. (O) Lime water,—a white precipitate. (P) Ammonia,—a white precipitate, (Q) Carbonate of ammonia,—a white precipitate. (R) Some of the water was boiled with a little nitric acid, —ammionia added to this gave no precipitate. _(S) Oxalate of ammonia,— a precipitate. ie (T) Nitrate of barytes,—a precipitate insoluble in nitric acid. (U) Nitrate of silver,—a white precipitate insoluble in nitric acid. (V) Sulphuretted Analysis of the Hot Springs at Bath. 345 (V) Sulphuretted hydrogen water,—no precipitate or change of colour; the water became very slightly turbid. (W) Prussiate of potash,—no immediate effect: after some weeks the water became slightly green. (X) Infusion of galls,—immediately a peach-blossom red colour, and very soon a precipitate which became dark purple by exposure to the air. All the above effects are also produced after the water has been cooled, excepting that the colour of tincture of tur- meric is not then destroyed, and, under some circumstances, no red colour occurs upon the addition of infusion of galls. (Y) A quantity of the water was evaporated to dryness, and distilled water added to the residuum. Nitrate of lime poured into the solution afforded a crystalline precipitate. in a few hours, indicating the presence of an alkaline sul- phate. I shall now state the inferences to be deduced from these experiments. Carbonic acid exists in this water (BE). A considerable portion of it escapes at the high temperature at which the water is obtained, its evolution occasioning the precipitation of some substance which it beld in solution (K). From Experiment (L) it is evident that no sulphuretted hydrogen gas is present. As no alteration of colour is effected upon tincture of lit- mus by the carbonic acid (M), it is evident that acid is pre- sent only in sufficient quantity to dissolve the substance pre- cipitated by its evolution. The destruction of the colour of tincture of turmeric (N) is clearly occasioned by the gas during its passage through the water (D). The effect produced in Experiment (O) is owing to the formation of carbonate of lime, and the precipitation of it and of the substance previously dissolved by carbonic acid (K). A part of the precipitate obtained by adding ammonia (P) must have been similar to that of Experiment (K), and to a portion of that of Experiment (O), produced in (P) and (O) by combining the solyent carbonic acid instead of expelling it $46 Analysis of the Hot Springs at Bath. it as in Experiment (K). The precipitate was carbonate of lime, or of magnesia, or both. As earthy carbonates are not precipitable by alkaline car- bounates, the precipitate formed by carbonate of ammonia (Q) indicates the presence of some other earthy salt. From Experiment (R) it appears that no alumina or mag- nesia exists in the water, and that the precipitate obtained in Experiment (K) was carbonate of lime. But according to Dr. Gibbes, sulphate of alumina is present. It appears, how- ever, that Dr. Saunders is perfectly correct in supposing that it forms no part of the saline contents of the water. In ad-+ dition to the experiments already stated, it may be shown to be incompatible with the salts actually existing im it; for the addition of a solution of sulphate of alumina occasions immediate precipitation. As Dr. Gibbes has insisted on this point, I shall here mention what appear to have been the causes of his mistake. In reply to Dr. Saunders’s supposition, that the precipitate which he took for alumina was carbonate of lime, he has stated that it was precipitated from the water by ammonia after oxalic acid had ceased to produce any further effect. This method is subject to error; for the oxalic acid appears to have been employed without previous combination with an alkali; and, as oxalate uf lime is soluble in oxalic acid, it is evident that, if more of the latter were employed than was sufficient to precipitate the lime, it would dissolve'a portion of oxalate of lime. The acid in combination with the lime previous to the addition of oxalic acid, not having an alkali to combine with, would dissolve a further portion of oxalate of lime; and unless the carbonic acid was expelled or saturated, it also would increase the error. From thesé circumstances I suspect that the precipitate afforded by am- monia was oxalate of lime, this compound being precipitable from acids by alkalies. Experiment (S) determines the presence of lime. Experiment (1) shows that sulphuric acid exists in the water. The effect, produced by nitrate of silver (U) results from the action of muriatic acid. ; As Analysis of the Hot Springs at Bath. 34F As no metallic oxide, discoverable by sulphuretted hydro- gen, was suspected, the appearance it produced (V) was supposed to be derived from its action upon carbonate of lime. This was ascertained to be the case by direct experi- ment. The prussiate employed by Experiment (W) was the triple compound containing oxide of iron, It was ima- gined that the slight greenness which was assumed by the water might be occasioned by the action of the carbonic acid, notwithstanding its holding carbonate of hme in soln~ tion, this effect being easily produced by the application of the stronger acids. A small quantity of the triple prussiate was therefore added to a solution of carbonate of lime in carbonic acid: after a considerable time it acquired a green colour exactly similar to that observed in Experiment (W). Dr. Falconer has indeed stated that a blue colour ts to be ob- tained by the action of prussiate of potash upon the water ; but, as it did not occur ull after the addition of sulphuric acid, it is evident that this effect was produced by the action of the acid upon the oxide of iron of the prussiate. Although the presence of oxide of iron is not at al] indi- cated by prussiate of potash, (probably on account of the smallness of its quantity,) yet it is evident from the action of infusion of galls (X) that a minute portion of it actually exists in the water; the light colour of the recent precipi- tate, and its becoming darker hy contact with atmospheric air, showing that it is in the state of protoxide. In making this experiment it is requisite to use a very small quantity of the infusion of galls; for, if much more than five drops of it are added to one ounce of the water, no indication of oxide of iron is produced, the water becoming of a light reddish brown colour, and affording no precipitate. An excess of this infusion re-acts upon the compound of vegetable matter and oxide of iron so completely as to prevent the appear- ‘ances readily presented by a small quantity. From the well known laws of chemical affinity it is evi- dent that the oxide of iron is combined with carbonic acid ; this compound undergoing some curious changes, which have occasioned much diseussion. It 348 Analysis of the Hot Springs at Bath. It has been observed, that one of the most active tests of oxide of iron does not in this water produce any appearance of its presence; and the slight metallic taste which it com- municates when hot and fresh has been unnoticed by some analysts. This taste is lost by cooling, even in well stopped botiles; and every method which I have tried to restore it — has been unsuccessful. It has also been mentioned that the action of infusion of galls is in some cases lost. The proofs that this water contains oxide of iron thus ex- isting under singular circumstances, and liable to cease, it is not surprising that they have been assisted by collateral evi- defce. Jt has been asserted that the water deposits ** a pale yellow ochrey precipitate;” but this is certainly an error, the precipitate being perfectly white. Another circumstance which bas been adduced to prove the precipitation of oxide of iron is, that the sides of the king’s bath become encrusted with it: this observation, as to fact, is correct; but the oxide appears not to be deposited from the water, but derived from the stone, by the increased oxidation of the iron con- tained in it, by the alternate application of air and water. Having procured a specimen of oolite similar to that of which the sides of the bath are constructed, I added a drop or two of nitric acid to it; by this the iron became instantly and completely oxygenated, affording an appearance similar to that which has been supposed to be deposited from the water. Another fact has been noticed equally deceptive with the above stated, which is, that the clothes of the bathers be- come stained with tron moulds. | It 1s indeed true, that the bright yellow colour of the substance of which these clothes are made changes toa brown; but this change is not partial, nor has it any resemblance to iron moulds: it seems to be effeeted merely by the decay of the colouring matter, and I find that solutions of tron do not change the yellow colour. The observation which has occasioned most discussion especting the oxide of iron, is the loss of power of infusion of galls to detect it. The following experiments will show under what circumstances this occurs. (2) About one pint of the water was exposed, while hot, to Analisis of the Hot Springs at Bath. 349 te the atmosphere in a vessel of broad surface. After it had remained about 16 hours, a small quantity of carbonate of lime was deposited by the evolution of carbonic acid gas. The precipitate was perfeetly white, and had not the slightest appearance of containing oxide of iron. -To this water in- fusion of galls was added without occasioning the least al- teration of colour. (2) As the quantity of oxide of iron in the water is evi- dently extremely small, it may be imagined that it was pre- cipitated with the carbonate of lime, but escaped observation from the minuteness of the quantity. To obviate this ob- jection, some of the water was)closely stopped in a phial for four or five days: upon examination it was found to possess its transparency perfectly, and without having afforded any precipitate; to some of this, infusion of galls was added without producing the slightest indication of oxide of iron. (c) Some of the water which had been cooled so as to re- tain its transparency, was heated to its original temperature ; infusion of galls was then added, but without producing any effect. The facts exhibited in Experiments ()) and (¢) have been long known, and have given rise to an idea that the iron is volatilized. Although this opinion is incompatible with facts already mentioned, yet it may not be amiss to show more particularly that it is completely erroneous. As it can- not be imagined that the temperature of the water is sufficient to volatilize mere oxide of iron, the existence of some sub- stance capable of carrying it off must have been supposed. That muriatic acid and muriate of ammonia possess this power at high temperatures is well known, but no uncom- bined muriatic acid or muriate of ammonia is present. Hy- drogen gas is said also to be capable of volatilizing iron ; but the gas eyolved from the water has been shown to consist of nitrogen gas and a small quantity of carbonic acid gas, and to neither of these gases, alone or combined, has any such power been attributed. If, however, they really possess it in this instance, they must be regarded as the solvent of the iron, and the effect produced upon infusion of galls must. be de~ rived 350 Analysis of the Hot Springs at Bath: rived from the gas diffused in small quantity through the water. If this be the case, the application of the concen- trated solution of iron should produce 2 much more distinct. effect upon the infusion; but it has been shown (D) that the gas destroys the colour of infusion of galls instead of increasing it, which would be the effect if it contained oxide of iron. | (d) About one gallon of the water was put into a vessel of considerable depth, of which it occupied about two- thirds: it was slightly covered, and remained about twenty- four hours. It then retained its power of affording a peach- blossom coloured precipitate with infusion of galls (X) in a very considerable degree. It is remarkable that in this experiment the result should have proved so different from that obtained in one where the circumstances were similar, excepting only the form of the vessel and the quantity of the water. When the water was exposed with a broad surface, infusion of galls showed no action on it (a); but here, even after eight hours longer exposure, it detected oxide of iron. From this circumstance I began to suspect that some change was produced by the absorption of oxygen, and that it had not produced the same effect in this as in the former experiment, on account of the quantity of the water and depth of the vessel. There appeared, however, a strong fact against this supposition; viz. that iron is more easily detected when highly oxygenated, whereas the reverse ef= fect in this case was produced. To try the effect of atmospheric air, the following experi- ments were performed : (e) A small quantity of the water was enclosed, while hot, _inawell stopped phial, with about one-fortieth of its volume of atmospheric air, After four days the water remained per- fectly transparent, but the addition of infusion of galls did not afford the slightest appearance of its containing iron. (f) Another portion of the water was kept for the same length of time in a well stopped phial,. but without any air except such as the water held in solution, - Infusion of galls occasioned Analysis of the Hot Springs at Bath. 351 occasioned exactly the same appearance of iron in this as im the water when fresh and hot (X). That the action of infusion of galls is lost by the absorp- tion of the oxygen of atmospheric air is proved by the fol- lowing experiment : (g) A third quantity of the water was enclosed, with the usual precaution, in a phials about one-half of which was occupied by the gas evolved from the water in the bath, which has been shown to contain no oxygen gas. After four days, infusion of galls was added to it, and gave the Same appearances of oxide of iron as occur in its application to the fresh hot water. Having thus ascertained the effect of oxygen in preventing the action of infusion of galls upon oxide of iron, it remained to be shown in what manner this is effected. I imagined it might be produced by increasing the power of combination of the oxide of iron so as to admit of its acting upon the earthy contents of the water and forming compounds, the strong affinity of the constituents of which prevented the action of the infusion of galls. With a view to ascertain how far this supposition was correct, I examined the effects produced by adding carbonate of lime, dissolved by carbonie acid, to solution of sulphate of iron to which infusion of galls had been previously added ; and although it will appear, by the following experiments, that the alterations produced upon the oxide of iron in the water are caused by the car- bonate of lime it contains, it will also be found th:t they are not effected in the way I had supposed. A very dilute solution of green sulphate of iron was pre- pared: the quantity of oxide of iron contained in it was so small as scarcely to afford any alteration of colour when in- fusion of galls was added to it; but upon pouring solution of carbonate of lime into it after infusion of galls had been added, a deep red colour was almost instantaneously pro- duced. Although this fact did not immediately appear likely to solve the difficulties attendant upon the water in question, yct it was snfficiently striking to merit an examination by what 352 Analysis of the Hot Springs at Bath. what means the carbonate of lime produced this effect, and to what extent it might be employed in rendering infusion of galls a more active re-agent. With this intention I boiled some crystallized sulphate of iron in alcohol till nearly the whole of the red sulphate was separated. The remaining quantity being extremely small, I shall consider the iron in this solution as entirely in the state of protoxide. The sulphate, insoluble in alcohol, was dissolyed in water, and the quantity of the oxide contained in a given portion of the solution was ascertained by taking the average of two experiments. (h) To one ounce of this solution, containing rasodth of a grain of protoxide of iron, infusion of galls was added. This occasioned the usual appearances indicated by the pre- sence of oxide of iron in a very slight degree. The colour produced, increased by the absorption of the oxygen of the atmosphere. (?) An equal quantity of the solution was treated with prussiate of potash. A light blue colour was immediately produced by the minute portion of peroxide of iron which had escaped the action of the alcohol: the intensity of this colour was gradually increased by the action of atmospheric air till the iron had arrived at its maximum of oxidizement. (k) Infuion of galls was added to one ounce of a dilute solution of carbonate of lime containing +3,,dth of a grain of oxide, as in the former experiments. A red purple colour, of very considerable intensity, was immediately produced. (2) The last experiment was repeated, employing only sotosdth of a grain of oxide instead of -3>5dth. A very distinct red purple was immediately produced by the action of the infusion of galls. (m) To one ounce of a solution of carbonate of lime, con- taining +;5dth of a grain of exide, prussiate of potash was added ; but it did not produce any indication of having acted upon the oxide of iron. I now prepared a solution of red sulphate of iron by treat- ing the green sulphate with nitric acid in ared heat. The quantity of oxide which the solution contained was as in the former Analysis of the Hot Springs at Bath. 353 former case ascertained. The experiments made with this were as follow: (n) One ounce of a solution of red sulphate of iron, con- taining _2,,dth of a grain of oxide, was treated with infu- sion of galis. The usual indications of its action upon oxide of iron were presented. (0) The addition of prussiate of potash to an equal quan- tity of the solution immediately occasioned a blue co- lour. (p) Infusion of galls was added to one ounce of a dilute solution of carbonate of lime containing ;,!,dth of a grain of the peroxide of iron. Slight indications of its action upon the oxide were produced, but the colour was scarcely more intense than that effected by ~,4,,dth of a grain of protox- ide in similar circumstances: no effect whatever was pro- duced by infusion of galls upon ~>},cdth of a grain of per- oxide in one ounce of solution of carbonate of lime. The colour produced when carbonate of lime and infusion of galls are added to the peroxide is red purple, similar to that occasioned by their action upon the protoxide. (g) To one ounce of a solution of carbonate of lime, con- taining, as in the last experiment, 72;,dth of a grain of peroxide of iron, prussiate of potash was added. Not the slightest blue colour was produced. When carbonate of lime was thus added to the solution of peroxide of iron, 1 found that it was capable of preventing the action of prus- siate of potash upon z1>th of a grain. From these experiments it is evident that carbonate of lime possesses, in a very great degree, the power of in- ereasing the action of infusion of galls upon protoxide of iron; while, on the contrary, it diminishes its power in de- tecting peroxide of iron; and is, moreover, capable of pre- venting the action of prussiate of potash. The application of these experiments to the circumstances of the water in question is obvious. It has been shown that it contains carbonate of lime; and that the power of infusion of galls to detect the oxide of iron it contains is completely lost by the absorption of oxygen. The following experi- Vol. 24. No. 96, Mey 1806. Z ment 354 Analysis of the Hot Springs at Bath. ment was made with the intention of trying whether this effect of slow, oxidizement might be imitated : (r) Infusion of galls is, as has been seen, capable of acting upon +;455dth of a grain of protoxide of iron in one ounce of solution of carbonate of lime (/). A portion of sulphate of iron containing =,!,,dth of a grain of protoxide was dis- solved in one ounce of dilute solution of carbonate of lime, and was kept in contact, with about one-fourth of its volume of atmospheric air, during twenty-four hours. At the end of that time the solution remained perfectly transparent, and without having precipitated ; but the addition of infusion of galls did not occasion the slightest appearance of having acted upon the oxide of iron. In this experiment the loss of power of infusion of galls is much more speedily effected than in the Bath water., This is evidently owing to the at- mospherie air contained in the distilled water employed, while no oxygen gas is present in the Bath water. When carbonate of lime is added to sulphate of iron it is well known that double decomposition takes place, the iron being thus combined with the carbonic acid instead of the sulphuric. Having found that infusion of galls, in several instances, acts each more readily upon carbonates than sulphates, I imagined that the carbonate of lime produced its effect in this way. To ascertain whether this supposition was correct I made the following experiment : (s) A quantity of the solution of green sulphate of iron, similar to that employed in the above-related experiments, was decomposed by carbonate of potash ; carbonic acid gas was passed through water in which the washed carbonate of iron was diffused, and to some of the filtered solution in- fusion of galls was added ; but, instead of the red purple co- lour effected by the action of carbonate of lime upon sul- phate of iron and. infusion of galls (k) and (/), the usual deep blue colour was obtained. (¢) One-tenth of the quantity of carbonate of iron em- ployed in the Jast experiment was dissolved in a solution of carbonate of lime equal in measure to the last solution. To this. infusion. of galls was added, The red purple : , colour Analysis of the Hot Springs at Bath. 355 colour was immediately produced, and from its intensity it was evident that carbonate of lime had increased the powcr of infusion of galls as much in employing the carbonate as the sulphate of iron. It may be concluded, from these experiments, that the ef- fects produced by carbonate of lime are not attributable en- _tirely, if at all, to the conversion of the sulphate of iron into a carbonate. Hence I was induced to examine the ap- pearances produced by the action of the various alkalies and earths upon infusion of galls and solutions of iron. The results are by no means uninteresting, but the limits usually allotted to an analysis will hardly admit of the necessary de- tail; I shall therefore relate only such facts a3 appear requi- site to explain the changes occurring in the Bath water, re- serving the statement of the remaining experiments for a future opportunity. I now proceeded to examine the salts produced by eva- porating the water and crystallisation, (u) A quantity of the water was evaporated to dryness : the residuum was treated with distilled water as long as that fluid continued to dissolve any portion of it. This solution was again evaporated, and upon cooling yielded a considera- ble quantity of acicular crystals. These were again dissolved in distilled water; and to a part of the solution nitrate of ba- rytes was added, which occasioned a copious precipitate. The same effect was produced by oxalate of ammonia ; but ammonia caused no precipitation, These crystals were there- fore sulphate of lime. By further evaporation the solution afforded cubic crystals of muriate of soda and prismatic cry- stals of sulphate of soda. The next object to be attained was the weight of the total quantity of the various substances held in solution bya given portion of the water. This has been given, with consider- able variation, by different analysis, as will appear by the following statement. From a quart of the water Dr. Lucas obtained 334 grains of dry residuum, Dr. Charlton - 34 Dr. Falconer + 17% Dr. Gibbes -~ 234 Z2 Te 356 Analysis of the Hot Springs at Bath. To account for the great difference of these results, Dr. Satinders has supposed that the water varies at different times, or that the residuum has been dried with various degrees of heat. Ihave ascertained the quantity of the contents of the water several times during about eighteen months, without observing any other variation in its weight than is unavoida- ble in experiment. In support of this observation it may be remarked, that I found its specific gravity exactly as stated by Dr. Falconer. It is scarcely probable that the results of any of these analyses were obtained by drying the residuum at a lower temperature than 212°, or at a greater than a red heat. Now I find that one quart of the water, weighing 30 troy ounces 172 gtains, at the temperature of 63°, gives 32 grains of residuum dried at 212°: when the heat of a sand-bath is employed, 30 grains are obtained; and at a red heat, 28 grains. The greatest variation afforded by these methods is four grains; whereas from some cause, which it is difficult to explain, the extreme difference of the experiments above cited is 161 grains. When a red heat is employed, a part of the loss is occasioned by the decomposition of the carbo-: nate of lime; for water poured upon the residuum turns turmeric paper of a reddish brown colour. The greater part of the residuum is perfectly white ; the portion ‘deposited at the upper part of the vessel is, however, slightly greyish, but not at all appearing as if coloured by oxide of iron. I suspected that it might be occasioned by carbonaceous mat- ter: to ascertain whether this was the case, the following experiment was made: (v) Four pints of the water were evaporated to dryness in a retort, and the residuum boiled with about five ounces of alcohol. The filtered solution left, on evaporation, 8°3 grains _ of a yellowish-coloured substance. A part of this was dis+ solved in water, and afforded a copious white precipitate with nitrate of silver, but did not give any with ammonia or with carbonate of ammonia: muriate of soda was therefore the only salt dissolved by the alcohol. » (w) To the remaining portion of: the saline mass colour- less sulphuric acid was added. By heating, the acid acquired Q a dark Analysis of the Hot Springs at Bath. 357 a dark brown colour, evidently derived from its action upon carbonaceous matter. This experiment did not appear con- clusive, as two causes of error might have existed,—a small quantity of alcohol was probably decomposed by the action of the salts upon it, or some of the conferva which is found in the water might have escaped notice previous to evapora- tion. I had recourse, therefore, to other means. Mr. Kirwan, in his Treatise on the Analysis of Mineral Waters, gives a method for ascertaining the presence and quantity of extractive matter proposed by Westrumb, which consists in precipitating the muriatic salts by nitrate of lead, and after- wards the extractive matter by nitrate of silver. It is impose sible to conceive any method more completely fallacious than this; for extractive matter is as readily precipitated by nitrate of Jead as by nitrate of silver; and although muriate of soda is decomposed by nitrate of lead, muriate of lead being a salt of considerable solubility, the subsequent addi- tion of nitrate of silver would decompose it, and afford a precipitate consisting of muriate of silver without any ex- tractive matter. The power of sulphuric acid to detect carbonaceous matter is extremely great: ;-1,dth of a grain of sugar was dissolved in four ounces of water; to this solution about one ounce of sulphuric acid was added: it was then boiled till nearly the whole of the water was evaporated, and the acid had ac- quired a very distinct brown colour. The following experiment was now made: (x) A quantity of sulphuric acid was added to one quart of the water perfectly transparent, and free from heteroge- neous matter. The mixture was evaporated nearly to dry- ness in aretort, and the acid remained perfectly colour- less. The water, therefore, contains no carbonaccous matter. The substances contained in the water, as shown by the foregoing experiments, are ; carbonate of lime, oxide of iron, sulphate of lime, muriate of soda, and sulphate of soda. The presence of these compounds has been universally allowed ; but that silica is contained in the water, was discovered by Z3 Dr. 358 Analysis of the Hot Springs at Bath. Dr. Gibbes. To find the quantity of each of these, the fol- lowing methods were employed : (y) A quart of the water was evaporated to dryness in a " platina crucible: the residuum, dried in a sand heat, weighed thirty grains. This was boiled, with successive portions of distilled water, till it ceased to afford a precipitate with ni- trate of barytes. The solution was then divided into three equal quantities. (z) To one of these portions nitrate of silver was added as long as precipitation took place, and distilled water was poured on the precipitate till it came away quite pure. The muriate of silver thus obtained was weighed after exsiccation, (A) The second quantity was treated with oxalate of am- monia while it continued to produce any effect. The preci- pitated oxalate of lime was washed, dried, and weighed. (B) To the remaining part of the solution nitrate of ba- rytes was added till it ceased to produce any precipitate ; and the sulphate of barytes obtained by its action was weighed, after washing and drying, as in the former expe- riments. (C) The residuum, insoluble in water, weighed, when dried, two grains: nitric acid added to it dissolved 1°7 grains. This solution afforded no precipitate with ammonia, but a copious one with oxalate of ammonia: it was therefore ni- trate of lime obtained by the decomposition of the carbonate. (D) The +3 of a grain left by the nitric acid was dis- solved by potash, and precipitated from it by muriate of am- monia. This precipitate was not again soluble in nitric acid, and was consequently silica. Another quart of the water was treated in the same way. To avoid prolixity, I shall state the quantity of each precipi- tate afforded by one-third of a quart multiplied by three, and make the requisite calculations from the mean of the two experiments. Exp: I. Exp. II. Mean. Residuum - 30° grains 30° 30° Muriate of silver 16°2 do. 16:2 16'2 Oxalate of litne 18°3 do. 17°7 18° Sulphate Anaiysis of the Hot Springs at Bath. 359 Exp. I. Exp. IJ. Mean. Sulphate of barytes 36-6 grains 36°9 36°7 Carbonate of lime 1:7 do. 1°5 16 Silica Par GO; *4 *35 According to Dr. Gibbes, a quart of the water affords nearly 4 grains of silica when treated in the method I have described. Thinking it probable that a portion of it might be taken up by the action of the salts during their solution im water, I tried whether any larger quantity could be ob- tained by the following method : (£) A quart of the water was evaporated to dryness in a platina crucible. The residuum was repeatedly treated with nitric acid in a red heat; the soluble parts were again dis- solved by distilled water, and the portion insoluble in it, - when dried, weighed -4 of a grain. This agreeing exactly with the last experiment, I shall consider as the quantity of silica afforded by a quart of the water. This experiment was several times repeated, with very little variation in the weight of the result, but was sometimes evidently coloured by oxide of iron, which was separated from the silica, and its nature ascertained by the usual means. But, even when employing apparently perfectly similar means, the oxide of iron was not always to be obtained,—an effect attributable to the decomposition of the muriate of soda by the nitric acid, and to the power which muriatic acid possesses of carrying off oxide of iron; but for the uncertainty of its action it is not easy to account. To find the quantity of oxide of iron contained in the water, the following means were employed ; (F) To a quantity of the hot water infusion of galls was added in the requisite proportion. The water measured when cold 91 pints. The. precipitate obtained was separated by the filter, and dried :—the precipitate and filter were then burned together in a platina crucible, and the carbonaceous matter of the filter, and that combined with the iron, were got rid of by the application of a red heat, The residuum was then treated with nitric acid, jn order completely to oxidize the iron:—it was then boiled with acctic acid to Wet ade Z4 take 1 360 Analysis of the Hot Springs at Bath. take up the lime precipitated with the oxide of iron by the infusion of galls ; and afterwards with potash, to dissolve any silica which the filter might have furnished—the re- maining substance was evidently oxide of iron, and weighed °2 of a grain. (G) The last experiment was repeated, slightly varying the method. Infusion of galls was added, as before, to a quantity of the hot water, measuring after it had cooled 174 pints. The precipitate was suffered to subside, and the wa- ter poured off till only a small quantity remained. This was evaporated, and the residuum, treated with nitric acid in a red heat, weighed ‘5 of a grain. Being exposed to a red heat with carbonaceous matter, it became magnetic, and dis- solved in muriaticacid, except!gth of agrain, which appear- ed to be silica, derived from the water evaporated to obtain the precipitate formed by infusion of galls. The muriatic solution afforded a blue precipitate with prussiate of potash, -4 were therefore oxide of iron. According to the experiment (F) one quart of the water. affords *00421 of a grain of oxide of iron, and by the second 00463, giving a mean of 00442 ; but the iron in the water is in the state of protoxide; and as:the peroxide consists of 66°5 protoxide, and 33°5 oxygen, *00442 will give -00394, the quantity of protoxide of iron in one quart. 242 of muriate of silver indicate 100 of muriate of soda, 16°2 will therefore give 6°6. 100 of oxalate of lime are produced by 100 of sulphate of lime, 18 will then give 18. 100 of sulphate of lime afford 175 of sulphate of barytes, 18 will then produce 31°5, which subtracted from 36°7, the whole quantity of sulphate of barytes obtained, leave 5:2 for the sulphate of barytes formed by the sulphate of soda; and as 100 of sulphate of soda give 170 of sulphate of barytes, 5°2 yield 3. One quart of the water therefore contains Carbonic acid - 2°4 inches. Sulphate of lime - 18° grains. 20°4 Brought ¢ ‘ Se — Royal Society of London. 361 Brought forward - 20°4 - _Muriate of soda ies 6-6 Sulphate of soda - 30 Carbonate of lime 1-6 Silica - - 4 Oxide of iron = “00304 29°60394 Loss - “30606 30° Estimating the muriate and sulphate of soda in the cry- Stallised state, one pint of the water contains nearly as follows : Carbonic acid - 12 inch, Sulphate of lime - 9 grains. Muriate of soda = 31 Sulphate of soda - 32. Carbonate of lime - ats Silica - = x Oxide of iron — Je LXIII. Proceedings of Learned Societies. ROYAL SOCIETY.’ Mag t.. The right honourable the President in the chai. On resuming the reading of Mr. Smithson’s letter (not Tennant, as erroneously printed in our last report) it did not appear that the author had been able to collect any quantity of the native minium which he discovered in galena; nor does he mention in what country he found this mineral. An anatomical dissertation, by Mr. Home, on the teredo gigantea, or sea-worm, with observations on the teredo na- valis, or borer, was also read. The subject examined by this anatomist was one of those sea-worm shells brought by Mr. Griffiths from Sumatra, of which some account was given to the Royal Society in February last. The teredo na- valis was brought from one of our ships at the Nore, in or- der 362 Royal Society of London. der to enable the author to pursue his inquiry into the com- parative anatomy of these animals. In the stomach of the borer he found a considerable quantity of matter, which Mr, Tennant pronounced to be purely ligneous, and similar to saw-dust. Notwithstanding this circumstance, and that of the borer’s burying itself always in timber, Mr, Home concludes that wood is not properly its food, as it passes undigested ; but that the animal, as well as the feredo gi- gantea, draws its nourishment from the water. May 8. The President in the chair.—On this evening was read a letter from Mr. O. Gregory, of the Royal Military Academy at Woolwich, on sir Isaac Newton’s definition of the force of the lever, in which the author defended sir Isaac’s demonstration as the most simple and correct, against all the objections urged by other mathematicians. Mr. G, reduced his defehcs: to propositions illustrated by figures, and maintained that the force of a lever of the same length and weight was equal in whatever other direction it might pass from the fulcrum, as well as horizontal. May 15. The President in the chair—An interesting let- ter to the President, from Mr. T. A. Knight, on the invert- ed action of the alburnous vessels of plants, was read. Mr, Knight, discovering some facts in opposition to the senti- ments of Hales and Duhamel, has taken much pains to con- firm them by experiments, all of which have tended to prove the truth of the opinions and observations which he has communicated from time to time to the society, relative to the circulation of the juices in plants, formation of buds and sap-wood, and to vegetable physiology in general. In the present case his ee were directed to ne roots of po-= tatocs, and he in consequence maintains that the formation of all such roots is explicable only on the principle which he has been endeavouring to establish, that of the ¢verted action of the alburnous vessels in plants. His experiments seem to have been conducted with his usual accuracy, and Jeave little doubt of the truth of /his observations and opi- nions. Perhaps the discoveries of this ingenious philoso- phical botanist may be found directly applicable to the use of hot-house or green-house plants, in directing the gar- 1 dener’s Pod Society of Antiquaries. 363 dener’s attention to the supply of that kind of air most easi- ly assimilated by the lungs or respiratory organs of the diffe- rent species of bulbous- and tuberous-rooted plants, and thereby find a new pabulum vite vegetalilis. It is, how- ever, certain that we are yet very ignorant of the indefinite improvability of vegetables, and of the best means of mul- tiplying them for the use of animal life. May 22. The President in the chair.—& Weather. <4 Sle] z Inches. |] = 5 Th me 222 45°| 52°) 43°|.30°10 | 22° Cloudy 42 | 47 | 40 | 29°78 25 43 | 55 | 45 “56 35 Cloudy 46 | 54 | 46 *67— 28 |Showery 50 | 56 } 51 *80 29 |Cloudy 54 | 63 | 53 “60 4g {Fair 48 | 46 | 41 “78 oO {Rain 45 | 46 |.44 | 30°06 ‘17 |Rain 44 | 52 | 46 "02 5 |Rain 50 | 64 | 55 | 29°78 30. «(|Fair 55 | 68 | 55 *59 36 {Fair 56 | 69 | 56 *56 45 {Fair 54 | 63 | 56 *50 15 |Cloudy 55 | 67 | 55 65 60 |Fair 50 | 62 |-55 °80 11 {Cloudy 50 | 59 | 45 “75 2) Fair 45 | 51 | 48 *70 5 |Cloudy 50 | 60 | 52 “40 Oo |Rain 55 | 62 | 53 *59 42 |Fair 55 | 66 | 54 “94 51. |Fair 54 | 65 | 55 | 30°02 41 |Fair 58 | 70 | 54 *30 70 Fair 56 | 65 | 51 *35 65 |Fair 52 | 69 | 50 720 66 {Fair 51 | 48 | 68 ‘18 50 |Fair 50 | 62 | 51 *20 60 |Fair 54 | 71. | 52 “02 62 {Fair 56 | 73 | 61 | 29°99 57, \Fair 6o | 73 | 59 “90 a1 baie N. B. The barometer’s height is taken at noon. re INDEX ro VOL. XXIV. ACADEMY at Erfurt, 89; at Gottingen, go ; at Turin, 275; of Genoa, 284; Stockholm, 355 Acid, muriatic. ok by Galvanism, g1, 167, 170, 172, 176, 185, 244 Acids, Effects of, on urinary cal- cult, 25, 120 Aérosiation, 282, 367 Affinities, chemical, On, 284, 350 Agricultural machine. Patent, 387 Alkalies. . Effects of, on urinary calcul, 2'Sy BES American Societies, 282. Analysis of chromate of iron, 33 ot guano, 126; of birdlime, 1313 of ox bones, 264; of Paris waters, 2863; of sulphu- retted oxide of manganese,3 24; of Bath hot springs, 342 Anatomy, 180 Antimony. On combinations of, 236 Antiquaries. Society of, §3, 181; 276, 363 Antiguitics, 284 Mpod:s. ‘Two new genera of, 329 Artillery. Patent, 190 Asafetida. Expet. on, 63 Astroblepus, On the, 329 Astronomy, 188 Atheneum at Poictiers, 365 Atmosphere. State of water in, 1033; Marine. On, 272 Az:te, gas:ous oxide of. On, 57, 216 On production. Balsams. Exper. on, 61 Barley. Exper. on, 64 Bath, Analysis of the hot springs at, 342 Beans, Exper. on, 64 Beet-ro0t sugar, gt Benzoin. Exper. on, 61 Biddle’s experiment on frozen mercury examined, 322 Birdlime. To prepare, 1315; pro- perties and analyses of, 134 Bitumen, On production a Sy Blue, Prussian. On, -234 Bohbea tea a cure for dropsy, gt Books, New, 265, 368 Botan 5 89 British Institution, 8 Brossy on density of frozen mer- cury, 322 Buch on muriatic acid and soda produced by Galvanism, 244 Buds. On reproduction of, 75 Cachemire goat, On the, 97 Calcul, urinary. On, 25, 114 Camphor. Exper. on, 64 Canals. Patent relating to, 94 Caoutchouc. On, 39 Caras, playing. Origin of, 180 Carey’s meteorological tables, 96, 192, 288, 373 Catalepsy cured by vital air, 246 Caterpillars. To destroy, 213 Ceres. Tables of, 188 Chain-pumps. Patent, 1QI China. Russian embassy to, 93, 366 Chromate DN D&E XxX. Chromate of iron. Analysis of, 3 Cioni on production of mufiatic acid by Galvanism, 167 Cities. Antient, discovered, 284 Civilization, A prize aates 188 Clark’s patent, 1gt Clough’s patent, 1g! Coffee. Spirits from, 368 Collard on chemical afin. 284 Collenbuch on urine, 44 Cometarium. Waiker’s, 37 Compression. Effects of, on heat, 140, 193 Cotenhagen. Society of Sciences, 187 Copper precipitated by iin! 284 Crane. Patent, 94 Cranks and flys. Patent respect- ing, 94 Crusades, A prize question, 278 Curr’s patent, 190 Cuthbertson on production of mu- riatic acid by Galvanism, 170 Dalton on elastic fluids, 8, 15-3 on absorption of, by water, &c. 153; on theory of mixed, 103 Pamp-er’s patent, 199 D-afncse cured, 92 Decarro on the Cachemire goat, Di:panon gaseous oxide of azote, 215 Distillation. Improvement in, 37 Dropsy cured by bohea tea, gt Dufour on destroying insects in gatdens, 213 Danbar’s creteorological observ- ations, 95 Dunkp’s new quadrant, 363 Dyeing, Ou, 49, 69 Earth. Rotatory metion of, 93 Lconomigal Sociviy, Bahama, 282 Ligon on gravelly and calculous concretions, 25, bi4 Eliustic fuids, On, §, 15 $75 Electrical experimen's, 73 Electrogene of Schmidt. On, 250 Epilepsy cured by vital air, 247 Eremophilus. On the, 329 Erfurt Academy, 89 Faliing hodics. Ov, 93 Filtration ou a large scale, 314 Linsbury Dispensary, 225 Fire-arms. Patent, 94 Flinders’ meteorological remarks, 27% Fluids, elastic. On, 8, 85 3 wei: slit of, 245 on respiring, 51 ; the- ory of mixed, 103 Flys and cranks. Patent respect- ing, Fossil skeleton found in Glouces- tershire, 92 Fourcroy’s analysis of bones, 262 Freezing. A prize question, 187 French National Institute, 278 Galvanie Society, Paris, 183 Galvanic chain described, 183 Galvanism, GI, 267,170, 172, 176, 183, 203 Gases. On mixtures of, 8; on absorption of, by water, &c. 15; on weight of, 245 on re- spiting, 51, 2155 theory of mixed, 103 Gasomeier. Steevens’s, 163 Germain on spirits from potatoes, 209 Gibson on sutures in skulls, 256 Goerlitz Society, 187 Gold, On oxide of, 6a Gétingen Academy, 69; univer- sity, 187 Gravelly concretions. On, 25» 184 Gregory’s treati:e of mechanics, Account of, 265 Grego y on the lever, 362 Griffiths on a worm-sicll, 82 ee : ° 2. Grinding of woods, &c. Patent for, 196 Ae ey? ee 6 Gusiccum, Exper. on, 4 Guano. 376 Guano. On; 126 Gums. Exper.on; | 62, 63, 81 Gun-locks. Patent; 1g9t Hall (Sir J.) on heat modified by compression, 140, 193, 294 Hatchet on tannin, 58, 81, 155 #iaus:man on metallic oxides and dyeing, €9 Hawking on vaccination, — 204 Heat. Effects of, modified by compression, — 140, 193, 291 Hemp spinning. Patent ior, 190 Hen. A remarkable, 287 Hermbstad:’s black dye, 49 Herschel on solar motton, 180 Hides. Patent for splitting, 191 Higgins on manufacture of sugar, 3038 Hill on pneumatic medicine, 247 Hinchliffe’s patent, 19! Holbein’s Dance of Death, de- stroyed, g2 Flolme on caoutchouc, 39 Home on prostate gland, 1803 on sea worm, 361 ‘Horsce-shoes. Patent, Ig Hortentz on prodvetion of mu- riates by Galvanism, gt Humboldt on two new genera of apodes, 329; on pimelodus, 3333; Of a new species of monkey, 339 Fapan. Russian embassy to, 93 Iceland. Improvement of, 283 imperial Bing Turin, 278 Imperial Russian Scciety, 304 Lndian rekber. On, 39 Luadigo. Exper. on, 595-73 Lasecis. To destroy in ap Fobnston’s wiproved worm- -tuby 37 Fancs's patent, Ot fron. White sulphate of, 72 —. On oxidation of, 223; sulphates of, 226; prussiate of, 232 INDEX. Juno. Tables of; 183 Reir’s patent, 287 Kentish’s patent, 94 Kepler. Monument to; 188 Knight on the reproduction of buds, 75; on vegetable phy- siology, g62 Lac. Exper. on, ‘6r Lady Raleigh’s \etters, 364 Lagrange on birdlime, I3t Lassalle’s patent, 287 Laudanum. Cure for deleterious effects of, 47 Laugier’s analysis of chromate of iron, 3 Learned Societies, 81, 180, 36 Leather, Patent for glazing and graining,1g0; for splitting, 191 Lectures, 189, 287, 372 Liquorice. Exper. on, 63 Literature. Russian, 93; a Lehi question, 3 65 Logan’s patent, 190 Lnndoh Institution, 274. Longevity, 372 Lysons on playing cards, 180 M‘Adam’s patent, 19k Magnesia found in bones, 262 Manganese. On oxide of, 69; Analysis of sulphuretted oxide of, 324 Manna. Exp. on, Manure. On a natural, Marine ainosphere, On the, 272 Marshall’s patent, 94 Martin on geology, 363 Mechanics. New works on, 265, 2¢9 Medical Society, Lyons, 282 ;. Brussels, 366 Medicine, 47) 91, 92, 246, 247 eh On density of frozen, 322 Metesrology, 95, 96, 192, 288 Mews. Meaning of the term, 84 Miller’s patent, 287 Mineralogy, 285 Mines. ISNaDgJEVx: Afines, Patent for working, 287 Mins/rels, antient. On, 83 Mississipi river. Meteorological observations at, 95 Monkey. New species of, Moon. Ou apparent magnitude of, 240 Muriates. Production of, by Gal- vanism, Ql, 167 Muscovade Sugar, Manufacture of, 308 Music, 234 Neylor’s patent, 94+ Optical phenomena, 240 Orsted on sound, 251 Oizley’s patent, Igt Oxidation of metals, 2e3 Oxides, metalic. On, 69 Oxygen gas. On respiring, 53 Pacchiani, on composition of mu- riatic acid, Pallas, Tables of, Park, the traveller, 371 Parr’s patent, ¥gL Patent inventions. 94, 190, 287, 372 Peas, Exp. on, 64 Pelts. Patent for splitting, 191 Petrini, on production of muria- tic acid by Galvanism, 167 Pfaf’s experiments on respira- tion, _ $1 Pimelodus. New srecies of, 333 Pit coal, Origin of, Br, Places patent, 1g1 Plunkett's patent, 287 Phillips's analysis of Bath hot springs, 342 Phillips’s patents, Pneumatic medicine. On, 47,246, ; 247 Potash. Oa production of, gi Potatoes. To extract spirits from, 209 Preston's patent, 287 Prize questions, 187, 278, 281, 282, 365, 306, 369 339° 377 Prussiates of iron. On, 232 Publications, new, 265, 308 Resins. Exper. on, 60, 8x Respiration. Experiments on, 5% Rotting. Patent to prevent, 3190 Royal Society, 81, 180, 271, 361 Royal Colizge of Surgeons, 276 Royal Jennerian Society, 84. Royal Society, Copenhagen, 365 Royal Academy, Stickholn, 365 Russian Embassies, 36, 366 Salt, Patent for making, 94 Sampson’s patent, 94 Sarcocol. Exp. on, 63 Schmidt’s electrogene. On, 250 Ships. Machine for transporting, 189 Skins. Patent for splitting, 191 Smiihson’s discovery of native minium, 274 Soap. Patent, . 287 Sveicties. Learned, 81, 180, 36% Soda. On production of, g1, 244 Sonorous vibrations. On, 2¢1 Spar. Recent production of, r8z Spirits from potatoes, 209 Stesvens's gasometer, 163 Sternberg on electrogene, 250 Stone-sacving. Patent for, ~g4 Sugar. From beet-root, 91; on manufacture of, 308 Sulphate, white, of iron, 7% Sulphates of iron, On, 226 Surgery, 286 On, 250 Syphon. New application of, 37 Sutures in skulls of animals. Tannin. Hatchet on, 58, 8x, 155 Taun/on’s dispensaxy report, 222 Taxation, a prize question, 187, 365 Tea, a cure for dropsy, gi Telescope, patent, 190 Thenard on combinations of an- timony and tin, 236 Tin. On oxide of, 69; combi- nation of antimony with, 236 Tinder-lox, patent, | 94 hornton 473 INDEX. Thornton on pneumatic medicine, 47, 246 Tragacanth. Exp. on, 6 Transit instruments. Walker on, 289 Travels, 286 Trusses, patent, rol, 2b. University, Gottingen, 596 Uric acid. On, - 25 Urine. On prognostics from, 44 Vaccination, 84, 188, 204, 270s 281 Vauquelin on guano, 126; on sulphuretted oxide of manga- nese, 324 Volcanoes of the Andes, 333 Walker's Cometarium, Walker. On magnitude of moon, 240; On transit instruments, 289 West's patent, 1990 Wheat. Exp. on, 64 White lead, Patent, 287 Whytock's patent, b Zora) Willcox’s patent, rg0 Winds. On, , 272 Woodhouse’s patent, 94 Yarn. Patent for dressing, 192 ERRATA. Page 166, line 10, for “ the solution,” &c. read “ the sil- ver, again dissolved in nitric acid and diluted,” &c.—Page 167, 1.18, for “ Civnu,’’ read “ Cronr.”—Page 183, 1. 18, for ** tension,’’ read ** charge.” The plate of Mr. Steevens’s Gasometer, instead of being numbered PI. I[I. should be Pl. V. END OF THE TWENTY-FOURTH VOLUME. Printed by R. Taylor and Co., $8, Shoe Lane, Flect Streete gt Philo. Mag. PUL. Vol.AXIV. Horizontal view of Air in Water. Tnaumbent Stratum of Atmosphere Particles marked thus, « . Stratum of Air in Water marked thus Axotic k Hydrogenous Gas Distance of Particles 4to 1. x i | SSS Oxy genousNitrous 8 Carburetted Hydrogen Gas,_— Distance Particles 3 to 1. a, aise ey pes aM Phalo. Mag. Pl Il. Vol XXIV. Profile View eu we Water. oad IRs gar 64 Density. Oxygenous Nitrous & Carburetted Hydro- go gas 77 Density. ay PO AS ing. x ote ‘WAIYMFLINVTE SVAYTIFM WW Hi | q Lowry sculp Philo Mag PLIV Vol. XX1V- Liffects of Heat modified by Comprefsion . 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