摘要:

MEMOIRS AND PROCEEDINGS OF THE CHEMICAL SOCIETY OF LONDON FOR 1845-1846 AND 1847-1848. VOL. 111. LONDON PRINTED BY RICHARD AND JOHN E. TAYLOR RED LION COURT FLEET STREET. 1848. CONTENTS. PageOn the relation of Ozone to Hyponitric Acid. By Dr. C. F. Schoenbein 2 On the Composition of the Fire-Damp of the Newcastle Coal Mines. By Thomas Graham Esq.................................................... 7 Observations on the Resin of the Xunthorm hastdis or Yellow Gum- resin of New Holland. By John Stenhouse Esq. Ph.D. ......... 10 An Account of various Substances found in the Guano Deposits and in their Vicinity. By E. F. Teschemacher Esq. ..................... 13 On some Chemical Effects produced by Platinum.By Dr. C. F. Schoenbein .......... . . . . ... . .. . . . ... . ....,.. . .. . . ..... . ,............... . .. . .... 17 On the Wax of the Chamzrops. By J. E. Teschemacher Esq. ...... 24 New Researches upon Aniline. By A. W. Hofmtmn Ph.D. ......... 26 On Electrical Endosmose. By Mr. James Napier ....................... 28 Analysis of a Cobalt Ore found in Western India. By J. Middleton Esq. ............................................................................ 39 Notes on the Preparation of Alloxan. By William Gregory M.D .... 42 On the unequal Decomposition of Electrolytes and the Theory of Electrolysis. By Mr. James Napier ........,..... . . ..... . ...........,.. 47 On a convenient Instrument for graduating Glass Tubes ............... 54 Researches on Atomic Volume and Specific Gravity.By Lyon Play- fair Esq. Ph.D. and J. P. Joule Esq. ..............................,.. 57 On the Influence exerted by Electricity Platinum and Silver upon the Luminosity of Phosphorus. By Dr. C. F. Schoenbein............... 104 On Struvite a new Mineral. By G. L. Ulex.. ............................ 106 On Nitraniline a new Product of Decomposition of Dinitrobenzol. By James Sheridan Muspratt Ph.D. and Augustus William Hof-mann Ph.D. .................................................................. 111 On the Blue Compounds of Cyanogen and Iron. By Alexander W. Williamson Ph.D. ..... . . . . ..... . ................. . . . .... . ............. . ..... 125 Annual Report of the Council . . . .. . . . .. . ,..... .... . ... . ... . ..... . .. . . . . ... 140 On the Action of Hyponitric Acid upon Aqueous Solutions of Bro-mine and Chlorine. By Dr. C. F. Schoenbein .....,.....,.,,...,,,,.. 143 1v I’agr On the Substances contained in the Roccella tinctonh. By Edward Schunck Esq. .......................... .................................... 144 On the Constitution of Aqueous Solutions of Acids and Alkalies. ByJohn Joseph Griffin Esq. ......,...,, ..,,.,. . ,,............,.,......,.... 155 Researches on Atomic Volume and Specific Gravity. By James P. Joule Esq. and Lyon Playfair Esq. Ph.D. . . ,. . . . . . .. . ......... . ... 199 Researches upon Cumarine. By Hermann Bleibtreu .................. 205 On the Solvent Action of Drainage-Water on Soils.By John Wil-son Esq. ................................. .................................... 219 On Palmic Acid a Fat Acid related to the Margaryl Series. ByLyon Playfair Esq. Ph.D. ........ . ,.....,... . . ..... . ........... . ......... 222 On the Compounds of Phosphoric Acid with Aniline. By Edward Chambers Nicholson Esq. .... . . .... . ...... . .................. . . . . .. . . . . . . 227 On a Common Origin of the Acids (CH) 0 with a Boiling-pointunder 300’ Centigrade. By Dr. Joseph Redtenbacher. ........ . ..... . 235 On the Formation of Nitric Acid in Eudiometric Combustions of Gases mixed with Nitrogen. By Dr. H. Kolbe ..................... 245 On Tribasic Boracic 2Ether. By J. E. Bowman Esq. ............... 248 On Gun-Cotton. By E. F. Teschemacher Esq..................... . .*. 253 On the Chemical Composition of Gun-Cotton. By Messrs. Robert Porrett and E. F. Teschemacher .......................................... 258 hnalysis of the Water of the Thermal Sprirg of Bath (King’s Bath). By Messrs. George Merck and Robert Galloway ................. .... 262 Oti the Metaphosphates. By Robert MaddrelI Esq. .................. 273 On the Amount of Sulphur and Phosphorus in various Agricultural Crops. By Henry Clifton Sorby Esq. ................................. 281 Observations on the oxidizing power of Oxygen when disengaged by means of Voltaic Electricity. By H. Kolbe Esq. Ph.D. ......... 285 On the existence of a New Vegeto-Alkali in Gun-Cotton. By Robert Porrett Esq. ....................... . ........ ................... . .............. 287 On some new Researches in Animal Chemistry. Extracted from a Letter from Professor Liebig to Dr. A. W. Hofmann .....,............290 Ou the Salts of Sulphurous Acid. By J. Sheridan Muspratt Esq.,Pl1.D. ........................................................................... 292 Analysis of the Bohemian Glass as found in the Combustion Tubes employed in Organic Analysis. By Mr. Thomas Rowney ......... 299 On Thialdine and Selenaldine two new artificial organic bases. ByWiihler and Liebig ... . ...... . .................... . . . . .....................,... 303 Some Remarks on the Air and Water of Towns. By Robert Angus Smith Ph.D. .................................................................. 31 1 On the Action of a mixture of Red Prussiate of Potash and Caustic Alkali upon Colouring Matters.By John Mercer Esq. ..........,. 320 On the Composition of C‘atfein and of some of its Compounds. ByEdward Chambers Nirholson Esq. ....................................... 32 1 On the Preparation of Hippuric Acid. By William Gregory M.D ... 330 On the Decomposition of Water by Platinum and the Black Oxide of Iron at a white heat with some observations on the theory of Mr. Grove’s Experiments. By George Wilson M.D. ..................... 332 Annual Report of the Council ................................................ 344 On Transformations produced by Catalytic Bodies. By Lyon Play- fair Esq. ........................................................................348 Analysis of the Ashes of the Orange-Tree (Citrus aurantium). ByMessrs. Thomas H. Rowney and Henry How ........................ 370 On the Decomposition of Valerianic Acid by the Voltaic Current. ByH. Kolbe Ph.D ............................................................... 378 An Account of Experiments with Galvanic Couples immersed in pure water and in oxygenated water. By Mr. Richard Adie ............... 380 Upon the Chemical Constitution of Metacetonic Acid and some other Bodies related to it. By E. Frankland Esq. and H. Kolbe Ph.D. 386 On the Analysis of Hop-Ash. By Henry Watts B.A. ............... 392 On the Hydrates of Nitric Acid. By Mr. Arthur Smith ............... 399 On the Products of the Decomposition of Cuminate of Ammonia byHeat. By Mr.Frederick Field ............................................. 401 Contributions to the Chemical History of Gun-Cotton and Xyloidine. By Mr. John Hall Gladstone ............................................. 412 On the Action of Nitric Acid on Cymol. First Part. By H. M. Noad Esq. ..................................................................... 421 On some of the Products of Oxidation of Cumol by Nitric Acid. ByMr. F.A.Abel ..................................................... ........... 441 On the Preparation of absolute Alcohol and the Composition of ..Proof-Spirit.” By Mr. Joseph Drinkwater ........................ 447 On Cochineal (Coccus Cacti). First Memoir. By Warren de la Rue Esq. .............................................................................. 454 On the Nitrates of Bismuth and Copper. By Mr. John Hall Glad- stone ........................................................................... 480 On Crystallography with a Description of a New Gonionieter and Crystallonome. By H. B. Leeson M.D. ..............................486 V Puge

ISSN:0269-3127    

DOI:10.1039/MP84503FP001

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

Prof. Graham orr the Composition oj'Fire-Damp. CL. On the Composition ofthe Fire-Damp qf the Newca.de Cod Miites. By THOMAS Esq. F.R.S. GRAHAM SOME years ago I examined the gas of these mines with the same result as Dr. Henry Davp and llr. Turner had previously obtained namely that it contains no other coin- bustible ingredient than light carburetted hydrogen. But the analysis of the gas of the coal mines in Germany subsequently published showiiig the presence of other gases particularly ofolefiarit gas has rendered A new examination of the gas of the English mines desirable. The gases were,-l from a senin named the Five-Quarter seam in the Gateshead colliery where the gas is collected as it issues and used for lighting the mine; 2 the gas of Hebburri colliery which issues from a bore let down into the Brnsham seam-3 sentn of coal which is highly charged with gas and has been the cause of niany accidents; and 3 gas from Killingworth colliery in the neigh- bourhood of Jarrow where the last great explosion occurred.This last gas issues from a fissure in a stratum of sandstone arid has been kept uninterruptedly burning as the means of lighting the horse-road in the mine for upwards of ten years without any sensible diminution in its quantity. The gases were collected personally by my friend Mr. J. Hutchirison with every requisite precaution to ensure their purity and prevent admixture of atmospheric air. The usual eiidiometrical process of firing the gases with oxygen was sufficient to prove that they all consisted of light carburetted hydrogen with the exception of a few per cent.The results were as follows:-Gateshead Gas.-Specific gravity 0*5802. Carburetted hydrogen ....94*2 Nitrogen ......... 4.5 Oxygen ......... 1.3 100'0 The density of such a mixture is by calculation 0.5813. Killingworth Gas.-Specific gravity 0-6306. Cnrburetted hydrogen ....82.5 Nitrogen .........16*5 Oxygen ......... 1a0 1ooa Prof. Graham on the Composition ofthe The theoretical density of this gas deduced from its COM-position is 0*6308. The Hebburn gas was of specific gravity 0'6327. Seventy-nine measures of the Killingworth gas mixed with an equal volume of' chlorine left in the dark for eighteen hours and afterwards washed with alkali were reduced to 75 measures; from which the presence of 4 measures of ole-fiant gas might be inferred.But in a comparative experi- ment made at the same time on 85.3 measures of pure gas of the acetates mixed with an equal volume of chlorine a con- traction occurred of 1.3 measure; that is in exactly the same proportion as with the fire-damp. It was observed that phosphorus remains strongly luminous in these gases mixed with a little air while the addition to theni of one-four-hundredth part of olefiant gas or even a smaller proportion of the volatile hydrocarbon vapours de-stroyed this property. Olefiant gas itself and alt the allied hydrocarbons were thus excluded. Another property of pure light carburetted hydrogen ob-served by myself enabled me to exclude other combustible gases namely that the former gas is capable of entirely re- sistiiig the oxidating action of platinum black and yet permits other gases to be oxidated which are mixed with it even in the smallest proportion such as carbonic oxide and hydrogen the first slowly and the last very rapidly; air or oxygen gas being of course also present in the mixture.Now platinum black had not the smallest action on a mixture of the gas from the mines with air. No moisture appeared or sensible con- traction and no trace of carbonic acid could be discovered after a protracted contact of twenty-four hours ; while with the addition of one per cent. of hydrogen the first effects were conspicuously evident in three minutes and with the same proportion of carbonic oxide the gas became capable of affect-ing lime-water in half an hour.These experiments were re- peated upon each of the three specimens of firedamp. Yotnssium fused in the fire-damp did not become covered with the green fusible conipoiind of carbonic oxide nor occa- sion any contraction. Indeed however carefully the heat was applied to the potassium by means of an oil-bath a slight permanent expansion always ensued. The same thing oc- curred in pure gas of the acetates. It appeared that potas- sium could not be heated nbove 300' Fahr. in pure carbu- retted hydrogen without causing a decomposition and the evo- lution of free hydrogen gas. The gas was also inodorous and clearly contained no ap- Ijreciable quantity of any other coriibustible gas than light Fire-Damp of the Newcastle Coat Mines.carburetteil hydrogen. The only additional matters present were nitrogen and oxygen ; the specimen collected in the most favourable circumstances for the exclusion of atmospheric air namely that from the Bensham seam still containing 0-6per cent. of oxygen. The gases also contained no carbonic acid. It is worthy of observation that nothing oxidable at the temperature of the air is found in a volatile state associated with the perfect coal of the Newcastle beds. The remarkable absence of oxidnbility in light carburetted hydrogen appears to liave preserved that alone of all the conibustible gases ori- ginally evolved in the formation of coal and which are still found accompanying the imperfect lignite coal of Germany of which the gas has been examined.This fact is of geological interest as it proves that an almost indefinitely protracted oxidating action of the air must be taken into account in the formation of coal; air finding a gradual access through the thickest beds of superimposed strata whether these strata be in a dry state or humid. In regard to measures for preventing the explosion of the gas in coal mines and of mitigating the effects of such acci- dents I confine myself to two suggestions. The first has reference to the length of time which the fire-damp from its liglitiiess continues near the roof without mixing uniformly with the air circulating through the workings.It was found that a glass jar of six inches in length and one inch in dia- meter filled with fire-damp and left open with its mouth downwards continued to retain an explosive mixture for twenty minutes Now it is very desirable that the fire-damp should be mingled as soon as possible with the whole circulating stream of air as beyond a certain degree of dilution it ceases to be explosive. Mr. Buddle has stated “that immediately to the leeward of a blower thoukh for a considerable way the current may be highly explosive it often happens that after it has travelled a greater distance in the air-course it becomes perfectly blended and mixed with the air so that we can go into it with candles; hence before we had the use of the Davy lamp we intentionally made ‘long runs,’ for the piir- pose of mixing the air.” It is recommended that means be taken to promote an early interniixture of the fire-damp and air; the srnallest force is suflicient for this purpose; as a down- ward velocity of a few inches in the second will bring the light ps from the roof to the floor.The circulating stream might be agitated most easily by a light portable wheel with vanes turned by a boy and so placed as to impel the air in the di- rection of the ventilation and not to impede the draft. The gas at the roof undoubtedly ofteii acts as an explosive train 10 Dr. Stenhouse on the Resin of the Xanthoroes hastilis conveying the combustion to a great distance through the mine while its continuity woitld be broken by such mixirig and an explosion when it occurred be confined within nar- rower limits.Secondly no effective means exist for succouring the miners after the occurrence of an explosion although a large pro- portion of the deaths is not occasioned by fire or injuries from the force of the explosion but from suffocation by the after-damp or carbonic acid gas which diffuses itself after- wards through all parts of the mine. It is suggested that n cast-iron pipe from eight to twelve inches in diameter be permanently fixed in every shaft with blowing apparatus above by which air could be thrown down and the shaft itself immediately ventilated after the occurrence of an explo-sion. It is also dc-sirable that by means of fixed or flexible tubes this auxiliary circulation should be further extended and carried as far as practicable into the workings.

ISSN:0269-3127    

DOI:10.1039/MP8450300007

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

10 Dr. Stenhouse on the Resin of the Xanthoroes hastilis Nov. 17 1845.-John Thomas Cooper Esq. Vice -President in the Chair. ‘‘Taylor’s Calendar of the Meetings of the Scientific Societies of London for 1845 and 1846,” presented by the editor. W. H. Balmain Esq. was elected a Member of the Society. The following paper was read :-CLI. Observations 0% the Ilesin of the Xanthoroea hastilis or Yellow Gum-resinof New HoZlad. By JOHNSTENHOUSE Esq. Ph.D. THIS remarkable resin which is known in commerce as the yellow gum or acaroid resin of Botany Bay exudes from the Xuwthora?n hnstilis a tree which grows abundantly in New Holland especially in the neigh bourhood of Sidney. This resin was first described in Governor Phillips’s Voyage to New South Wales in 1788.Mr. Phillips states that it was employed by the natives and first settlers as a medicine in cases of diarrhea. The resin as it occurs in commerce sometimes forins masses of considerable size but as it is very brittle although tolerably hard it usiially arrives in the state of a coarse powder. Its colour is a deep yellow with a slightly reddish shade considerably resembling gamboge but darker and less pleasing. The colour of its powder is greenish yellow. When chewed it does not dissolve or stick to the teeth but tastes slightly astringent and aromatic like storax or benzoin. Its sniell is very agreeable and balsamic. When gently heated it melts and when strongly heated it burns with a strong smoky flame and emits a fragrant oclour or Yellow Gumresin of Kew Hollaiid.resembling balsam of Tolu. The resin contains a trace of an essential oil to which much of its agreeable sniell is probably .T owing. 1his oil passes into the receiver when the resin is distilled with a mixture of' carbonate of soda and water but its quantity is so small that I was unable to examine it more closely. The resin is insoluble in water but dissolves readily both in alcohol and in tether especially in the former. Its solution in alcohol has it brr/wnish yellow colour ; the addi- tion of water precipitates it as a dark yellow niass,but it does not crystallize out of its alcoholic solution when left to spon- taneous evaporation but remains as a varnish. When di- gested with strong alkaline lyes it readily dissolves and forms a brownish red solution; and when the alkali is neutralized with muriatic acid the resin is precipitated considerably altered as a dark brownish brittle mass.On concentrating the solu-tion out of which the resin has been precipitatetl and allowing it to coo! a quantity of impure reddish crystals resembling benzoic acid are gradually deposited. It requires repeated arid long-con tinued digestions with the strongest alkaline lyes to reimove the whole of this crystalline acid from the resin which retains it with very great tenacity. The quantity of the acid is by no means great. It is riot easily purified as its crystals are apt to retain a trace of a reddish eolouring matter from which it is very difficult to free them.The easiest wag of getting rid of it is by dissolving the impure crystals in a small quantity of alcohol and then adding water; the greater portion of the colouring matter is retained in solution while the crystals are precipitated tolerably white. When purified by repeated crystallizations they become quite colourless. In appearance taste and smell they closely resemble benzoic acid. When dried at 212' F. arid subjected to analysis,- I. 0.2284 grm. of substance gave 0-6005 CO and 0-113 EI 0. I I. 039.55 grm. of substance prepared on a different occn- siori gave 0.790 CO and O*1505 HO. Found. I. 11. Cinnarnic acid. Benzoic acid. C . 71-74 72-91 73-35 68.85 H . 5-49 5-65 5'32 4.9 1 0 . 22.77 21*44 21-33 26-24 100~00 100'00 1oo*oo 100'00 It is evident from these arialyses that the crystalline acid con- tains nearly the same amount of carbon and hydrogen as cinna- mic acid with some deficiency however in the carbon.I was led therefore to suspect that it consisted essentially of cinnamic 12 Dr. Stenhouse on the Resin Ofthe Xanthoroea hastilis. acid with probably a small admixtiire of benzoic acid a sus-picion which subsequent experiments tended fully to confirm ; for on heating a quantity of' the crystals with some peroxide of manganese and sulphuric acid oil of bitter almonds was immediately evolved and on boiling a second portion with hypochlorite of lime the very peculiar chlorinated oil de- scribed in a. former paper was also abundantly produced thus clearly indicating the presence of cinnamic acid.A third portion of the crystals was dissolved in alcohol and left to spontaneous evaporation; it yielded after some time the fine rhombic prisms so characteristic of cinnamic acid when it is crystallized out of alcohol mixed however with some long acicular crystals having all the appearance of benzoic acid I think myself warranted to conclude therefore that Botany Bay resin contains cinnarnic acid mixed with a very little her?-zoic in which respect it resembles balsam of Tolu which con- tains both cinnamic aid benzoic acids though fortunately in much greater abundance. Action of Nitric Acid 018 the Resin. When 'the resin is treated with moderately strong nitric acid in the cold a violent action ensues with the evolution of nitrous fumes.The resin is completely dissolved if the quan- tity of the nitric acid is considerable. The colour of the solu- tion is dark red but by boiling it becomes of a bright yellow colour. The liquid should be evaporated to dryness on the water-bath to get rid of the great excess of nitric acid. The residue forms a mass of fine yellow crystals consisting chiefly of carbazotic acid but mixed with some oxalic and a little nitrobenzoic acids. The nitrobenzoic acid is evidently de rived from the cinnamic acid in the resin. The carbazotic acid is easily separated from these other acids by converting it into carbazotate of potash which is easily purified by one or two crystallizations and then by decomposing the salt with muriatic acid pure carbazotic acid may be obtained.0.3823 grm. of the acid dried at 212O P. gnve 0.442 CO and 0-049HO. Found. Calculated numbers. Carbon . . 51-53 31-37 Hydrogen . 1.42 1-30 oxygen . . 6'7'05 67-33 1oo*oo 100-00 0*3975grm of the potash salt decomposed by sulphuric acid and then ignited with carbonate of ammonia left 0*1300 of sulphate .of potash =17*68per cent. of potash ; calculated quaiitity 1'7.60. Mr.E. F. Teschemacher 011 Substamesfrom Guano. 13 The silver salt was also formed by boiling the acid with car- boiiate of'silver. It is a very soluble salt which crystallizes in fine red-coloured needles. 0.S9'75 grm. of the salt gave 0'372 C1 Ag=31*28 Ag or 33'53 per cent. oxide. The calculated numbers are 31-27 per cent.of silver = 33*59oxide. The quantity of carbazotic acid which Botany Bay resin yields when treated with nitric acid is so great and it is so *. emly piirified that this resin seems likely to prove the best source of that substance. When the resin is subjected to destructive distillation in an iron or copper retort it yields a very large quantity of a heavy acid oil mixed with a very small quantity of a neutral oil which is lighter than water. If' however the resin has been previously digested with nlka- line lyes so as to remove all the cinnainic and benzoic acids it contains the heavy oil is obtained as before but none of the light essential oil. The acid oil is readily soluble in potash and soda lyes; in its smell and properties it resembles creos- ote; when it is digested with nitric acid it is wholly converted into carbazotic acid and when a slip of' fir-wood is dipt in it and then moistened with either muriatic or nitric acid the deep blue colour passing quickly into brown so characteristic of' hydrate of phenyle is immediately produced with which substance the oil appears conipletely identical.The light oil above mentioned the quantity of which is extremely small is separated from the hydrate of phenyle by saturating it with an alkali and distilling the mixture in a glass retort with a gentle heat. In snie!l and properties it resembles henzin and is most probably a mixture of benzin and cinnamene; unfor- tunately the quantity obtnined was so small that I was unable to subject it to more particular examination.

ISSN:0269-3127    

DOI:10.1039/MP8450300010

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

Mr.E. F. Teschemacher 011 Substamesfrom Guano. 13 December 1 1845.-The President in the Chair. William Johnson Esq. was elected a Member of the Society. The fdlowing communications were read :-CUT. An Account of various Sul,sta?rcesfound in the Guano Deposits and in their Vicinity. By E. F. TESCHEMACHEH Esq. REPORTS having been circulated that large quantities of saltpetre (nitrate of potash and nitrate of soda) were to be found of a very good quality in the neighbourhood of the guano deposits on the coast of Sfrica numerous vessels were dispatched both from London and Liverpool in search of those valuable substances particularly as it was considered they might be obtained upon the same terms as Ichaboe guano namely for nothing but the labour and expense of fetching.hlr. E. F. Tescheniacher on various Substances No favourable accounts however have as yet been received as to the success of these undertskings. The evidence of such c?eposits existing there at all was very unsatisfactory ; the circumstance milch relied upon was the existence of large beds of uitrate of soda in the neighbourhood of the coast of South Anierica and large deposits of guano similar in inany respects to the deposits of guano on the Africtin coast there was certui~ily an abundance of animal matter and arnmoniacal salts to furiiish the nitric acid and a temperature high enough to effect the decomposition but the source from whence the alkaline bases of potash and sods were to be derived was nut very evident.The principal source of saltpetre in the East Indies is from numerous districts of nitrous earth found on the surface of the soil which being compounds of linie and magnesia with nitric acid they are dissolved out and the saltpetre subsequently formed by the decomposition of these nitrous coinpounds by potash salts. The nitrate of soda salt-petre beds in the Province of Tarapaca near Iquiqua on the coast of South America are the only instances known of the occurreiice of saltpetre ready-formed in extensive beds but even this deposit coiitains the salt in a state of great impurity. These explorations however on the African coast have hrought to light various other substsnces which have been found there the details of which are more parricularly the ob-ject of' this communication.'l'he substances which I shall now describe are found in the guano beds or in their viciiiity either in a crystalline state or in distinct masses. The first substance is a crystalline salt perfectly transparent with a cleavage and hilliaiit t'aces in one diiectioii only ; it gives a yellow precipitate with nitrste of silver ; gives off aminoriia upon application of caustic pot-ash ai;d when heated to redness loses about 50 per cent. of water mid minionis ; I consider it therefore to be phosphate OJ ammonia. The portion of salt I examined consisted only of a few grains and was consequently too sniall a quaiitity to ana- lyse with exactness. The next substance was also a crystalline salt a little mixed \tith guano in its cavities; it possessed a cleavage with bril- liant planes in two directions upon examination with the re- Bectiiig goniometer it gave 112' as the measurement of the :iiigle tormed by the rneetiiig of the adjacent planes.Upon aiinlysis I found it to consist of-2 1f~parts of Ammonia. 55'50 ... Carbonic acid. 23.50 ... ivater. 100'00 Jbund in tile Gutmo Deposits and in their Y;ci?tity. IS being nearly eqiiivalent to 1 atom of ammonia 2 atoms of carbonic acid and 2 atonis of water. Formula NH +2CO + 2H0 and is consequently a bicrrrbonafe cfamrno?zin. The third sulxtance was fhnd at Saldanha Bay on the cwst of Africa irnbedded in patches in the mass of guano. It is fwnd in distinct crystals with numerous niodifications in:iny of tlie planes possessiiig sufficient brilliancy to enable ine to measure the angles by the reflecting gonionieter.have given the measurements of one crystal from which it appears the primary form is the right rhombic prisrn of 57' 30' and 122' 39' it has a cleavage parallel to plane hI*. Upoii analysis I find this substance to be composed of'-14.30 parts of Ammonia. 17-00 ... Magnesia. 30'40 ... Phosphoric acid. 35.10 ... Water. 99'SO which is nearly equivalent. to 1 atom animonia 1 atom mag-nesia 1 atom phosphoric acid 5 atoms water. Formula N H, MgO PO +5H 0. It is therefore the amn2onio-naa,rrnesian phosphnte. The spe-cific gyavity is 1-65 hardness 2; it falls to powder before the blowpipe giving off water aid atnmonia.It occurs white translucent sometimes coloured brown by the guano ; it rea-dily dissolves in weak acids. r-1 liis substance is clearly derived from the guano; but being insoluble iii water it must have been helcl in solution by some of' the orgaiiic acids of tlie guano and deposited there- from in large crystals as they are found but disseminated in patches only of the guano iii various parts of the beds. r1 1his suhstuiice not having been found before in a native state but hitherto only tweu known as one of the artificial products of the laboratory must be considered as R new mineral body; 1 therehe propose to give it the mineralo5i- cal name of Gicnnite this name being derived from the cir-cumstances and locality of its formation.The soi~rce from which the first two substances namely the phosphate ot' amrironia and the bicarbonate of ammonia are derived is clearly the peidation of water through the guano beds dissolving out these salts which running into lower * See the angular measurements subjoined. I6 Mr. E. F. Teschemacher on Substa?zcesfi.onz Guano. situations may be detained in lagoons and hollows of rocks where being subject to the high temperature of the climate they would be evaporated down leaving these salts in the crystalline state described. As guano contains abundance of these two salts it is possible there may exist considerable masses of them ; should this be the case it is evident that to the chemist in particular it would be of great interest as an additional source of these valuable salts.The chance of finding any considerable quantity of guanite in the state of crystals is not great but as it forms one of the ingredients of guano it is a substance of some import- ance. The application of it as a manure in combination with other ingredients is likely to be highly beneficial it beinga compound containing two important substances in an insoluble state namely ammonia and phosphoric acid; these may be taken up by plants only as they may be required and not be liable to be dissolved out of the soil or evaporated like other am moniacal salts. The last substance which I shall describe was also found imbedded in the guano from Saldanha Bay; it consists of small globular particles composed of concentric laminae slightly adhering together of a yellowish white colour containing in places portions of a similar nature which on fracture have ap-pearances of an organic structure like bone but on examina-tion by the microscope proved to be portions of shells resem- bling Nummulites.On analysis I found the substance to be composed of-37-50 parts Carbonate of lime. 32-50 ... Carbonate of magnesia. 12-00 Phosphate of lime. .I& ..b 12-00 Water with a little ammonia and animal matter. 3.00 ... Sand. 2.50 ... Alkaline sulphates and chlorides. 99.50 There does not appear to be any great quantity of this sub- stance. How it has been formed it is difficult to imagine; the composition is so very different either from that of bones or shells particularly in regard to the large quantity of car-bonate of magnesia which it contains. It is however probable that both bones and shells form the base of this substance and that partial decomposition having taken place the mag- nesia may have subsequently entered into combination with the carbonate and phosphate of lime. M' 011 /1 . 151'.00 M r;l eonf . . 112O.20 fon h. . 89O-30 h c' on f' . 112O.20 M 011 e . 142'*10 e oil c . 142'*10

ISSN:0269-3127    

DOI:10.1039/MP8450300013

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

CLIII. 011 some Chemical +$?cts produced by Platillurn. B-y fir. C. F. L CCHCENBEIN. SOME time ago I published an account of’a series of expe-riments made with the resin c)fgu:tiacurn from which it appeared that the substance named is inst:intly reridered blue not only hy chlorine and nitrous acid but also by bromine iodine ozo~ie,aiid it tiiirnber of metallic peroxides. Free oxygen lie it pure or mixed with nitrogen hydro- gen iiiid carbonic acid gas does not act in the dai*k upoii that ~*esi~ious matter and comparatively very little wheri exposed to the action of solar light. From these thcts it beconies mani- fest that 0xyg.m must have assumed a peculiar condition of cheniical excitement before it is capable of‘ causing the re-action mentioned.The beautiful experiments both of Ihvy and Doebereiner have demonstrated that platinum has the power to occasioii the oxidation of‘ a nuniber of suljstiinces under circumbtances in which that chemical action would riot take place wittiout the agency of that metal. ‘1’1~ blue coloration which the resiii of guaiacuni assumes under certain circumstances is most likely dependent iipori ;I partial oxidation of‘ that substance niid the latter being 50 very sen-sible to oxygeri that happens to be chemically excited it could easily be conjectured that platinum in a state of niinute mechanical divisioii put in contact with the resinous sul)staiice ineritioned niigtit cause the oxidation of the latter in the same manner :is that nietal occasions the oxiciatiori of‘ hy drogen aetlier and alcoliol.l’he fitcts I mi going to state will show that the correctness of this corijecture is fully borne out by experiment. Kewly-prepared spongy platinuni being placed lipon a piece of filtei-ing paper that had previously been rlrenclied with an alcoholic solution of resin of guaiaciim caused rather rapidly the appearance of blue spots at the place where the nietai had been in coritact with the resiiious solution. My experiments Chcm. SOC.Meni. VOL. I~J. C Dr. Schoenkin oia some Chemical Efects have further shown that that reaction takes place the more ra-pidly and intensely the more divided the platinum happens to be of which we make use in the experiment described. What is called Platinum Black acts therefore more energetically than spongy platinum does.From the facts stated it appears that platinum in a state of minute mechanical division con-ducts itself towards resin of guaiacuin like the simple halo- genous bodies ozone and a number of metallic peroxides. These facts demonstrate also that the coloration of the resin- ous matter being caused by platinum belongs to that series ofph~nomenawhich takes place when that metal is put in contact with a mixture of’oxygen and hydrogen oxygen and vapour of zether &c. In the paper above alluded to I have pointed out the re- markable coincidence that all the substances having the power of rendering blue the resin of guaiacum possess also the property of deconiyosing iodide of’ potassium transforming the yellow prwsiate of potash into the red one and I add decomposing sulphure tted and iod wetted hydrogen trans-forming sulphurous acid into sulphuric acid and destroying organic colouring matters.We shall presently see that pla- tiiium ill a state of miiiute mechaiiical division has the same power. If a crystal of pure iodide of potassinm be put upon a piece of filtering paper that has previously been moistened with di-stilled writer antl sporigy platiniini be placed upon that paper the spot touched by the metal assumes rather rapidly a brown- ish red colour. Tl’liis coloration does not result from free iodine but is most likely due to a compomd consisting of periodide of platinum antl iodide of potassium. That conjecture is founded upon the following facts.If a solution or iodide of potassium is put in contact with spongy platinum or platinum black the former assumes a perceptibly red colour which dis- appears on heating the solution to its boiling-point. Now it is well known that the cornpound before mentioned yields with water a red solution the colour of which is destroyed by heat Neither the red solution nor the brownish-red spots before mentioned are able to render blue paste of starch another proof that there is no free iodine in the case. The reaction described is most likely brought about in the following nian- ner the chemically excited oxygen surrounding the spongy platinum decomposes iodide of potassium a peculiar peroxide of potassium being formed and iodine eliminated.The latter in its nascent state combines with platinum to produce the periodide of that metal which itself unites with iodide of po-tassium into that compound yielding with water a red solw- p,,oduced by Plalimnt. tion. It is worthy of remark that a solution of iodide of potassium having been treated with spongy platinum enjoys the property of colouring blue the paste of starch on being mixed with dilute and pure sulphuric acid. The same re- action is exhibited by the same solution after it has been treated either with ozone or peroxide of lead. If some drops of a weak i. e. colourless solution of the yellow prussiate of potash be added to platinum black that solution assumes a perceptibly yellow colour arid yields with a solution of' che-mically pure sulphate of protoxide of iron a blue precipitate.From these facts it seems to follow that platinuni has the power to transform the yellow prussiate into the red one. Some years ago I tried to show that spotigy platinum being placed in an atmosphere of sulphuretted hydrogen loses its property of acting upon detonating gas on account of a film of sulphur being deposited on the surface of the metal. Such beiiig the case it would follow that spongy platinum has the pro erty to decompose sulphuretted hycirog:en. 8ulourless hydriodic acid on being mixed up with some platinum black assumes a brownish yellow coloui. which re- action indicates an eliinination of iodine. Several chemists particularly Dcebereiner Phillips arid Urunner have ascertained that spongy platinum produces sul-phuric acid on being placed in contact with moist oxygen anti sulphurous acid and there is no doubt that platinum black put into sulphurous acid gives rise to the fbrmation of sul-phuric acid.Moist filtering-paper being coloured by a soiu-tion of indigo and put in contact with spongy p1:itirium for about twentyfour hours appears entirely bleached at those spots which had touched ttie metal. I have repeated this ex- periment more than thirty times and always with the snnie result. This remarkable fact proves that platinuni in a state of minute mechariical division has the power of destroy-ing organic colouring matters and acts as a real tdeachiilg agent. Before passing to other subjects I must tiot omit to mention a circumstance which seems to me meriting some attention.It is a curious fact which has not escaped ttie notice of chemists that in more than one case platinum acts exactly like common eledcity both of them determining at the conimon temperature for instance the oxidation of free hydrogen. Now it being well known that nitric acid is formed if' electrical sparks are made to pass through moist air it seemed to me within the reach of possibility that the same acid might be prodwed by platinuni if that metal in a state of minute mechanical division were placed in contact with moist atmospheric air. Witli the view of ascertainiirg the c2 111,.Sichwiibein on sme Chmzicnl l$Gcfs correctness of that conjecture I put a piece of moist litmus p:iper in close contact either with spongy platinum or with platilium black.111 some cases part of the paper exhibited ;i slight reddish coloration part of‘it proved to be entirely bleached or iiearly so. I must however not omit to state that in the great miijority of my experinien ts I obtained bleach- iiig effects only aiitl no reddening of the litmus paper what-ever. I am u~ialile to account filr the difference of the results meritioiierl. Was the reddening of the litmus paper caused by some traces of nitric acid formed under the circumstances iiidicated ? 1am iiot prepfired at all to aiiswer that question. If nitric acid shoiiltl however Ipppeii to be produced under the circumsttinces irientioneci it would be a fkt in my opinion not very difficult to be :~ccouiited for.In whatever state the oxygen surrouiidiiig platiiiuni n121y be certain it is that that state is such as to i*ender oxygen very apt to combine at the common teniperature with a number of oxidable substances that would not be oxidized by common oxygen without the presence of pl;itiniini. ‘lY~etormation of nitric acid taking place under the circuiristaiices mentioned would indeed be a fact very similar to the comt,ustion OF detonating gas caused by platinum. 1 repeat however ttiat I consider the geuera- tion of nitric acid bi*oLigtit ahout by the agency of platinum as fiir from being est:tblistie~l by decisive facts. The voltaic chni-acter of bodies being so intimately con-nected with their chetnical riatiire that in most if not in all cases we may irif’er the one frum the other the fact I am going to state merits our attention.Clilorine bromine iodine ozone aiid a number of nietallic peroxides enjoy consider- able electro-niotive powers which are of such a kind as to render those bodies what is commonly called electro-negative. Ehce it conies that :t piece of metal being covered with any one of the bodies naiiietl bears to another commoii piece of the same metal the same voltaic relation as copper does to zinc. According to the experinierits of De In Rive and some other philosophers platinum foil being covered with some spongy .platiiium is negative to conimon platinum plate a lact which proves that in a voltaic point of view there exists a great analogy between the simple halogenous bodies ozone and metallic peroxides on one side and spongy platinum on the other.After hving stated n number of facts which clemonstriite the highly oxiclizirig powers of platinum we ask in what manner does that metal exalt the chemical activity of oxygen? Ttlis question has occiipiecl marly philosophers arid been answered in ve1.y different ways. Faratlay and Doebereher. p*o(Judby Hcriiir tun. ascribe to platinum the power of condensing oxygen so much as to deprive that element of its gaseous condition and think that coiidensed state to be the true cause of the oxidizing powers of platinum. Others (De la Riveand Gmelin) presume that oxygen is capaljle of cheitiically uniting with that metal and with those philosophers it is the oxide of platiniini that occasions the oxidation of Iiydrogen &c.Berzelius holds the opinion that the oxidatiotis caused by phtiiiuin are catn- lytical pht.mornena i. E. effects produced by some unknown force being innate to that nietal and ex;ilting the chemical attractive powers of oxygen. It is not my inteiition to enter into a discussion of those opinions; I shall confine myself to :I fkw general remarks tipon that interesting subject. As the conimon oxides of pla-tinum are not acted upon (at the common temperature) by free hydrogen as platiiium foil or wire that causes at a mode-rate temperature the combustion of (letonating gas exhibits :I perfect metallic surfkce while tlie tliirinest film of’ an oxide diniinishes or destroys the lustre of any metal and as pla-tinurn is a body that has a very weak affinity for oxygen I think that that nietal is nut capable of combining directly with the oxygen of’the air an(1 that De la Rive’s view of the subject is erroneous.Rut how is it with Fsraday’s and Doe-bereiner’s theory of the matter in question? It seems indeed to be tlie true one. Satisfactory however as that hypothesis may appear it is nevertheless possible that the oxidizing ac; tion of‘platinum may depend upon a cause different from what the philosophers tnentioned- consider as such. We know that phosphorus being put in contact with nioist atmospheric air gives rise to the formation of H highly oxi- dizing agent which as it has been shown elsewhere seems to be a peculiar compound of water and oxygen and enjoys the power of oxidizing a great number of substances at the comni~iitemperatiire.Now if phosphorii~enjoys that pro- perty it seems possible that some other substances for in-stance platinurn and iriditim niay do the same. In other ternis it appears possible that platinrim has the power to en- gender out of free oxygen and water a highly oxidizing per- oxide which surrounding that metal empowers the latter to cause all the oxidations ahove nientioned. In comparing the clieniical properties of platinum when minutely divided with those ofozone we cannot help being strnck by their great simi- larity as will appear fkom the following statements :-1. Both substances possess a negative electro-motive power.2. Both of theni destroy organic colouring matters. 3. Both of them reiider the resin of guaiacum blue. Ih. Schanbein 01) some Chemical Eects 4. Both of them decompose iodide of potassium. 5. Both of them change the yellow prussiate of potash into the red one. 6. Both of‘them transform sulphurous acid into sulphurie acid. 7. Both of them decompose oxalic and formic acids. 8. Both ofthein act in a sirniltir way upon Ether and alcohol. Great as the simihrity of properties may be it does not fol- low that platinum owes its oxidizing powers to a film of per- oxide of hydrogen being foriwct round the metal by a cata-lytical action of the latter.I have not yet succeeded in prod ducing by the means of spongy platinum and moist air an atmosphere exhibiting the peculiar electrical smell bleach- ing power and oxidizing properties which belong to ozone. Considering the great volatility of the last-named substance we shoiild slippose that it ought to disperse into the sur-rounding medium as soon as formed; or should ozone he re-tained by platinum in a way similar to that in which we think oxygen is attached to and condensed around that metal? Sup-posing oxygen to be an odoriferous substance it is manifest that the oxygen actually condensed by platinum could not affect the olt‘actory rierves. Another objection might be raised to the conjecture that it is a film of‘peroxide of’hydrop to which platinum owes its clxidizing powers from the fact that Thenmd’s oxygenized 11ater is really decomposed I)y platinum.Considering how- ever that ozone is in some respects strikingly different from Tti enn1. tl’s conipoun d,11av i11g for i nstaxice a pecu1iar odour being insoluble in water transforming both metallic silver and it.; basic oxide into a peroxide it appears possible that uzone is capa\)le of existing in the clcsest contact with pla-tinum without suffering deconiposition. I am not aware of sporigp pIatinuni or platinum black having been treated with ;inhydrous oxygen and I do riot know whether it has been ascertained if the latter is absorbed as easily by that metal :IS moist oxygen. It is equally unknown to me whether platinum after being placed in dry oxygen or air exhibits t!ie same properties as platinum after beiiig exposed for some time to the same gases when moist.If the oxidizing powers of platiuum should depend upon a film of peroxide of hydro-gen attached to that metal it is obvious that spoiig pltt-tinun; freed from its adhering water and placed withiii com-pletely dry oxygen could not assume oxidizing properties. Supposing however that spongy platinum acquires oxidiziiig powers under the circumstances mentioned we rimy never-theless imngiiie that those powers depend iipoii a filni of per pr.odnctd hy P~otit1t4/11 oxide of hydrogen surrounding that metal. De la Rive’s nnd Marignac’s experiments have shown that oxygen obtained from fused chlorate of potash on being exposed to the action of electrical sparks yields perceptible quantities of ozone.Now taking that odoriferous substance for a peroxide of hy-drogen we must admit that even that oxygen which is consi-dered as absolutely anhydrous still contains traces of aqueous vapour. ‘Taking for granted the hiiniidity of what is called dry oxygen we may easily conceive how platinum brought into an anhydrous mixture of oxygen and hydrogen could cause the comtiustion of the latter. Oiit of some oxygen and the traces of water still contained in what is considered anhy- drous detonating gas a film of peroxide of hydrogen would be formed around the spongy platinum ; that peroxide in the very moment of its being erigentlerd would oxidize n neigli-bouring portion of’ free hydrogen.The heat resulting fiiorn that oxidation would determine another portion of hydrogen to unite with oxygen. The heat proceeding from that che- mical union would occasion the combustion of an additional portioti of hydrogen and so on until the whole of the detona- ting gas should be consumed. The minute quantity of the peroxide of hydrogen attached to the spongy platinum woulcl act like a small conimon or electrical spark which as we we11 know is capable of setting the largest volume of detonating gas on fire. Electrical sparks acting upon a mixture of oxy- gen and hydrogen exactly in the snnie WRY as spongy pla- tinum does and it being a well-ascertained fact that ozoiie makes its appearance on causing common electricity to pass through (moist) oxygen it is possible that electricity and pln-tinuiii occasion the oxidation of hydrogen because both of them are able to produce ozone anti that it is to the agency of that odoriferous substance that we are to ascribe the che-mical effect mentioned.That conjecture must 1,ecome still more plausible if we take into account the Lict that spongy plntioum acts in a variety of other cases exactly like ozone. Taking this view of the case we could not admit that an electrical spark has the power to cause directly the formation of‘water out of detonating gas but should be obliged to con- sider the oxidation as occasioned by the ozone being formed under electrical influence out of aqueous vapour and oxygen In other terms we are obligeti to ascribe the oxidation to the same cause from which we derive the decomposition of iodide of potassium the transformation of the yellow prus- siate of potash into the red one the destruction of vegetable colouring matters the turning blue of the resin of guaiacunt the transformation of the protoside of lead into the peroxide Mr.J. E. Teschemacher on the &c. brought ahit by the electrical brush. Now as it can hardly be doubted any longer that the chemical eff'ects just stated are due to ozone produced by electricity the conjec- ture according to which free hydrogen may also he oxidized by electrical ozone seems to be very probable. Jntleed if po-tassiuni the hydrogen of colouring matters the oxide of lead &c. are oxidized by the oxygen of electrical ozone why should free hydrogen make an exception to the rule? But however that riiay be the subject under discussion seems to be iuterestiilg ai-rcl I add still obscure enough to offer an induceiiieut to chemists to apply themselves to its elucidutioii by further investigatioiis.The matter merits our atteiition the niore that it bears so close a relation to that series of chemical phamornenn which are called catalytical actions and which certaiiily belong to the most enigmatical facts ot' our science.

ISSN:0269-3127    

DOI:10.1039/MP8450300017

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

N!r. J. E. Teschemacher on the CLIV. 012 tlie Wax of the Chumm-ops, By J. E. TESCHEXACHER, Esq. BOUT three niillions of palm leaves are annually imported iiito the United States of' America for the purpose of being riianiifiictured into hats. They coiiie tied in bundles called iii Spaiiish Esteras each esfem weighing from 50 to 60 pounds; these ere the palinate part of the leaf with a small portion of the petiole ; this last weighs one-eighth of the leaf. The palm froin which the leaves are cut in Cuba and other parts of the West Indies for this purpose is a Chamzrops a low-growing species not differiiig 1 believe from tlie C. hu-miilis of the southern sections of the United States except in being much more robust in habit. 'The C. lztmilis of' tlie United States is too soft and yielding for this niaiiufacture.I have cultivated the p1a11t from Cuba for five or six years and was unable to discover any (liff'ereiice in foliage; but I have iiever seen the friiit of either. The leaf' of' the Chamaerops spreads out nearly horizontal with folds precisely like those of R lady's fin. On opening these foI(ls when they arrive in the United States in their dried state there is a qiiantity of white flaky powder under this is the bright varnish which covers the whole surface of the leaf; both these are true vegetable wax. From one of these plm leaves I obtaiiied by passing the tliunib down the folds 90 grains of the ~hitt:wax in pow-dery fl:ikes and by boiling the leaf after cutting in pieces in alcohol 300 grains more of a grayer coloured wax.At t!ie inaiiufactoiy the leaves itre often bleaclied by the Wax of !he Chaimwops. 25 fumes of sulphurous acid gas and then split by iiiachiriery into very thin strips ;this division cracks off of course a large por- tion of the brittle varnish which together with the white pow-der falls to the ground is swept together and burnt or thrown away. The weight of this substarice destroyed annually pro- bably exceeds one hundred thousand pounds. On treating this substance with a small quantity of boiling alcohol it may like other wax be separated into cerine and myricine. The powdery flakes first obtained contain about 80 per cent. niyricine and 20 per cent. cerine but the wax obtained from boiling the leaf in alcohol contains scarcely any niyricine.This is easily accounted fbr; the flakes being the brittle and more resinous part break off'readily ;while the alcohol which acts on the leaves dissolves only the cerine leaving the myri- cine undissolved ;this might no cloubt he obtained by increa- sing the quantity of alcohol and coiitinuing the process if it were desirable. In bees' wax the proportions of these two substances vary also the cerine from 70 to 90 per cent. myricine from iO to 30 per cent.; arid it is probable that the ~iioreor less brittle quality of all wax depends on the relative quantity of these two ingredients. The wax of Ceroxzlylou atidicola a very lofty palm found by Humboldt at Quindin on the Andes has been analysed ;tnd found very nearly to resemble bees' wax ill its ultimate 1)r in c itdes.Bees' wax. Palm wax. Carbon . . . . . 80.14 80-28 Hydrogen . . . . 14~08 13'20 Oxygen. . . . . 5-78 6'52 To obtain this wax the outer portion of the trunk is rasped or scraped the raspings are heated in water the wax swims at the top the other parts fall to the bottom the wax is col-lected made into small balls and dried in the sun; it has a deep yellow colour and when the resinous part (niyricine?) is uielted it has the appearance of amber ; after the separation of the wax and resin from the produce of Ceroxylon there remains in the alcohol a bitter yellow substance supposed to be a vegetable alkaloid. This yellow substance separates also from the wax of the leaf of Chani~rops but I think it is not an ingredient in the wax but of other parts of the juices dis- solved by the alcohol. The production from the juices of plants by a purely vege- table function of wax scarcely differing from that deposited in their hires by bees is calculatt.d to throw light 011 the qties-ti011 of the 1;mnation ot' this sul)stai~cebj these iiisects aid Dr. Hofniann’s New Researches upon Aiiiliire. also merits the careful examination of those who are entering into the study of the various trnnsfiirmations of the vegetable juices at different periods of their progress towards inaturiry.

ISSN:0269-3127    

DOI:10.1039/MP8450300024

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

Dr. Hofniann’s New Researches upon Adiire. Dec. 15 1845.-The President in the Chair. Several of the late Numbers of the Transactions of the Imperial Academy of St. Petershurgh were presented to the Society’s Library by the Academy. W. A. Miller M.D. Alfred S. Taylor Esq. Benjamin Brodie Eaq. and J. M. Neligan M.D. were elected Members. The following papers were read :-CLV. New Researches upon Aw’line. By A. W. HOFMANN, P1i.D. my former papers upon aniline I had repeated oppor-I”tunities of pointing out the remarkable analogy which exists between this body arid ammonia and at the coiiclusion of my memoir on chloraniliii and bronianilin I announced the existence of a compouiid which may be considered as urea in which ammonia is replaced by aniline.The discovery of this substance opened a new field for re-search inasniuch as it was to be expected that a11 the relations exhibited by ammonia and the metamorphoses it undergoes might be realized with aniline. A short titne after this communication M. Gerhardt in proceeding in this direction .tias prepared some products be- longing to the same series which are formed when oxdate of aniline is subjected to dry distillation or when chloride (If beiixoyl is acted on by aniline. I also have prepared these bodies but shall not enter into details upon them in this preliminary note in which I intend to describe some further results at wliicli I have arrived. The action of the vapour of cyanic acid itpon aniline is rather complicated ; a norinal cyumie oJ’aniZiiie (wen @‘mi-line) is best prepared by mixing a solution of sulphate of aniline with cyanate of potassa.The liquid after the lapse of a €ew moments becomes turbid and in an hour the whole solidifies into it crystalline rnass. By a simple recrystalliza- tion from water the new compound is obtained in a state of perfect purity. The combustion of this substance furnished results corre-sponding to the formula i. c. urea in which the ammonia is substituted by an equiva-leiit quantity of aniline. Dr. Hofnianri’s New Rusearches upon Ariilbie. From the properties of this cornpound it is evident that the elenleiits of aniline and cyanic acid undergo a similar transposition to that of the same acid and ammonia when forming urea.The body c,,H N2 0 is not the ordinary cyanate of aniline; it crystallizes without change from a concentrated solution in potassa audaekh dis-engage neither cyanic acid nor carbonic acid. The comportment of aniline with cymic acidinduced me to subject it also to the action of cyanogen and chloride of cynno-gen. In these reactions a series of new crystalline compounds is obtained which are still under examination. Not less reniarkable is the action of sidpfide ofcarbon upon aniline. When left in contact for some time with this com- pound aniline with evolukion of hydrosulphuric acid is con-verted in to a white crystalline mass which is dificultly soluble in alcohol and may be purified with great facility. The analysis of this new compound yielded numbers correspond- ing with the following formula i.e. aniline which has lost 1 equivalent of hydrogen arid has assumed in its place a cornpoiind of carbon and sulphur CS which corresponds in composition to carboriic oxide. Aniline . . . C, H N Sulphocarbanilide . C, H N C S. This peculiar compound which is neither acid nor base is likewise obtained in a niost interesting transformation i. e. the decomposition of sulphocyniiate of aniline by destructive distillation. The sulphocarbanilide as we may provisionally term this new compound is only slowly changed by reagents. The continued action of an alcoholic solution of potassa however drcoinposes it. After three or four hours’ boiling the solution contains a large proportion of sulphide of potassium and on cooling deposits a substance crystallizing in large brilliant needles which is a new compound.By analysis the numbers obtained gave the following for- mula c,,H NO which shows that these crystals are fornied simply by an ex-change of the sulphur of the former conipound with the oxygen of the potassa. Other oxides produce the same effect as potassa. On boil-ing sulphocarbanilide with oxide of mercury the red colour soon disappears black siilphide of mercury bring formed. 2s Mr. J. Napier 011 EZech*icnlEtidos~itose. According to the above fi)~niiila,this new substance whicli is also an indifferent lmdy may lie considered as aniline which has lost 1 equivalent of hydrogen and assunled the elenierits or cartionic oxide.Aniline . . . C, H N Carbanilide . . . C, €3 N C 0; and this view suggested to nie at once another experiment which was quite successful. If the above-given formula expresses the true composition of this substance if it be indeed cnrbaniZi& it was extremely probable if not certain that it might be produced by the di-rect action of chZo?*o-caz.bo?zic acid (pliosgmegas) upon aniline. C, H N -+ CO C1 = C, H N C 0 + HCl y ----J Aniline. Phosgene. Carbanilide. On introducing aniline into a 1)aIlooii filled with chloro-cai+onic acid the glass becanie so hot that it burst. On cool-ing the liquid solidified into a white crystallirie mass which by the action of water was resolved into hyvdi*ochloi~ateof a11il ine anti carbni I iI id e. This is indeed a far easier way of obtaining this substance in the st;cte of purity. On mixing aniline with oil (If ?nustord at first no change was observed; after the lapse of some months however the solution had deposited splen(1id four-sided tahles consti tu tiiig evidently the coinpou 11 d correspond ing to th iosi n 11amine. When brou@t in contact will1 tritochloride of phosphoz.us or ch/oi*ideOJ'sziicoit anilirie is likewise converted iiito crystal- line coinpoui~cls.

ISSN:0269-3127    

DOI:10.1039/MP8450300026

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

CLVI. 011 Electricul Eudosniose. By Mr. JAMESNAPIER. HAT two dissimilar solutions separated by a porous par- T tition will pass the one into the other is a pliaerioriienon long observed the only necessary condition being that the liqiiids have a strong tendency to cotnhine and that the one is more capable of entering into or wetting the porous par-tition than the other. The liquids eminently fitted to effect this are alcohol mid water and saturated solutions of sonie salts and pure water. But the phenomenon of endosniose takes place also when an electric current passes through liquids separated by a porous partition. When all the above con- ditions are absent aid even wklen these conditions are pre- sent the endosmotic current will follow the electric althougfi in ;1 cotitrary direction to that which would take place were Mr .J.Nap ier 011 E'lrctrictrl EtJ closmose. 29 there no electric current passing showing that under these circumstances it has its origin in the passage of the electric force. This fhct was first matle known by Mr. Porrett in the Annals of Philosophy for 1816. The object of' iliis paper is not to define the cause but to point out the different conditions of electrical endosmose and the important part it plays in electro-chemical investigation. The conditions under which electrical endosinose are ob-served are that the two metals constituting a battery or the two electrocles of a battery be placed in separate vessels or divisions of the same vessel ; one of the vessels or partition being composed of a nxtterial suficiently close in texture to prevent the mixture of'the two liquids and porous enough to allow the electricity to permeate through it.The substances generally used are bladder parchment unglazed porcelain &c. ?'tie last is what I have generally used in the experi- merits to be detailed. ,. 1he general effects of electrical endosmose are a portion of the psitive solution passes along with the electric current into the negative solution not by electrolytic action as has been generally supposed but by endosmotic action ; and this endosiiiotic current is coiifined to the direct influence of the electric current or facing the metals composing the electrodes or battery. There art some circumstances in which the posi- tive solution gains in quantity making an apparent curreiit contrary to tlie electrical; these will be referred to as we proceed.Electrical endosniose manifests itself in two ways or rather is of' two kinds which may be distinguished as the mensurable and the iwimcasui.czbIe the fornier being the result of the trans- fer of' water fimni one cell to another the latter of'a salt or acid lielcl in solutioii and which is being decornposed; this rnay take place to a11 extent equal to the ~iiole salt lieltl in solution in the positive cell without the quantity of' the two solutions being niatei.ially altered ; mid that this transfer is front eiidosinose will be best illustrated by de~iling a few exper i in e11 t s stati r 1g how e ve r that the invest igat ion n ecess ar i 1y involves :t pat nuiiiber of experiments the whole of which I cannot detail and the conclusions come to have been the result ofthese.It may be stated here that the vessel or divi-sion in which the positive electrode or metal is placed is termed the positive solution and the negative division the negative solution. 1. 20 ounces of water in which were dissolved 600 grains of sulphate of copper were inade the positive solution arid other 20 oiinces of' water with 500 grains ofsulpliate of cop- Mr. J. Napier Electrical Errdosmose. per were made the negative soIution. A copper electrode previously weighed was put into each of these solutions and connected with a Wollaston's battery of nine pairs the current allowed to pass until the negative solution was completely exhausted of copper which required sixty-four hours the battery not renewed during the experiment.At the end of' the experiment the electrodes being again weighed the posi- tive had lost 257 grains the negative had increased 250 grains. The positive solution had lost 6 ounces by nieasure the iiega-tive had gained 4 ounces. The greatest portion of this change took place within the last ten hours. The 2 ounces lost are iiiostly from evaporation. The positive solution was evapo-rated and crystallized and there were obtained 905 grains of sulphate of copper 95 less than was originally dissolved ; but the partition being saturated with salt may account for a por-tion of the loss.The 500 grains which were originally in the negative solution would only contain 127 grains of metallic copper; but there is nearly double of this deposited showing that the salt had been transferred by some means fiom the positive to the negative in quantity amounting to nearly the whole of the salt originally dissolved in the positive solution. 11. 100 grains of sulphate of copper were dissolved in 4 ounces of water and put into each division in the same man-ner as the last experiment. The partition in this case was much closer in texture than the other; the same battery power was used and continued till the negative solution was exhausted which was nineteen hours. .The negative electrode being weighed it had increased 34-4grains; the negative solution had increased one-fourth of a11 ounce; the positive solutioii had lost three-eighths of an ounce.Comparing this experiment with the last there is a great discrepancy the only known cause being tlie closer texture of the diaphragm ; the transfer of the salt is only in the proportion of one-third that of the former and the measurable endosniose is still fur- ther out of proportion being only one-sixteenth ; while the amount of decomposition is only one-seventh of the 500 grains. The electrodes in both experiments were the same in size. The question now suggested itself whether tlie transfer of the copper salt from the positive to the negative cell was the result of endosmose or of electrolysis corresponding with the results of the late Professor Daniel1 and Professor Miller who supposed that certain bases underwent electrolytic transfer in fractional proportions and that these proportions might vary according to the texture of the diaphragm or that kind of' peculiar resistance given to the passage of a current when passing from one solution to another.Mr. J. Napier on Electrical Ihidosmose. In order to determine which was the true cause the nega-tive cell was charged with a weak solution of caustic potash the positive being sulphate of copper ; gas was freely evolved from the negative electrode; in a little time the porous dia- phragm facing the electrodes became coated with oxide of' copper which greatly retarded the current and niade it neces- sary to use ti more powerful battery.After twelve hours the oxide which had accumulated upon the diaphragm and at the bottoni of the positive cell was carefully collected washed dried and weighed 7'3 grains. The potash of the positive solution being neutralizecl by muriatic acid had a solution of chloride of barium added which gave a precipitate of sulphate of bwytes weighing 26 grains equal to about 9 grains of sul-phuric acid. From this it appeared that the copper had passed from the positive to the negative as sulphate of copper and therefore not by electrolysis. In repeating similar experiments with very dilute alkaline and earthy salts in the negative cell I have observed that the oxide of copper fornied being a conductor of electricity it often floated between the diaphragm and negative electrode as a kind of spongy fibre and condiicted the electricity through it as a solid constituting its extremity in connexion with the porous partition into the electrode the result being the reduc- tion of the oxide in and upon the diaphragm closing it up with metallic copper similar to that observed in the operations of electro-metallurgy when any of the electrodes are allowed to touch the diaphragm.It Iias often surprised me how nii-nute a fibre would connect the electrode and cell and produce a wide-spreading result. A solution of cyanide of potassium was next tried in the negative cell having sulphate of copper in the positive; the current passed four hours. The cyanide solution smelt strongly of hydrocyanic acid ; the solution was found to contain both copper and sulphate of potash ; the quantities were not de-termined.The next object was to use two salts of such a character that if that fi-om the positive cell passed to the negative by en- dosinose it would remain in solution ;if' by electrolysis the base would be reduced to the state of an insoluble oxide. The negative was accordingly charged with a solution of caustic potash and the positive with cyanide of copper and potassium the latter in excess After eight hours during which gas was freely evolved from the negative electrode and upon it was a sniall portion of copper powder no oxide was formed ; the solution contained cyanide of potassium and copper the latter being precipitated b~ hydrochloric acid and fused gave Mr.J. Napier on Electrical E)ido.srnose. 3'5 metallic copper with strong smell of hydrocyaaic acid. From this it appeared that both the copper and potassium salt were transferred by endosmose. The double cyanides of po-tassium and silver and of potassium and gold were next sub- stituted for the copper in the positive cell with similar results. Nitric acid was also substituted for the caustic potash iii the iiegative cell with the double cyanides of copper silver and gold iii the positive which would give the contrary result of last experiments namely -precipitating the metals if tram-ferred by endosmose Init dissolving or holding them in soh -tion if transferred hy electrolysis. In a short time in eacii experiment the surtace of the porous diaphragm facing the negytive electrode became coated with the cyanide of the metal which accumulated and dropped to the bottom of the vessel.At the termination of the experiments the acid solution smelt strongly of hydrocyanic acid and contained much nitrate of potash. With the gold aird silver salts the acid solution had not the slightest indication of their presence in solution but with the copper there was a corisiderable portion present which was owing to the cyaiiide of that metd being clecom-posed by nitric acid ; but this experiment being repeated with the copper cyanide in the positive and sulphuric acid in the iiegative no trace of copper in solution was found in the acid. ,7 1 he next experimmt was to determine if any portion of' the potassium of the potash salt was transferred by electrolysis ; tor this purpose two porous vessels were employed one filled with n solution of cyanide of' potassium the other with dilute nitric acid; these were placed in ii crlass Yessel containing a ? solution of nitrate of silver ; the positive electrode was placed in the cyanide of potassiurn the negative in the nitric acid.The cyanide of potassium which passed from the positive cell to the silver solution in the glass vessel was dec*oniposed pro-ducing cyanide of silver and nitrate of potash. After twelve hours the cyanide of silver formed was carefully collected washed and dried ; it weighed 65.6 grains ; the rernaiiiing silver solution had as much muriatic acid added as precipi-tated the silver.The clear filtered solution was now evapo-rated to dryness and kept for some time at the point of fusioii. There were obtained 28 grains of nitrate of potash which is 4 grains less than the equivalent of' cyanide of silver obtained ; but the nitric acid in the negative cell also contained a little nitrate of potash and silver which had passed from the glass vessel and will account for this loss. From these and a vwiety of other experiments of a similar kind with different salts I consider that no base of an electrolyte is transferred by electrolytic action but that salts being electrolysed are dl MI.. 33 J. N:rpier on Electrical Endosrrwse. transferid more or less from the positive to the negative elec- trodes by entlosmose aiiti that the amount of this varies nc- cording to the texture of the porous diaphragm the power of the electric current and \Jai*ious other niodifjing circuin- staiices which will be apparent as we proceed with the inquiry irito the cause and circutristances of electrical endosmose.111 refkrring to the first experiment it was observed that the greatest amount of nieasurahie endosniose took place during the last ten tiours when both solution and battery were nearly exhausted. 5OOgrains ot‘sulphate ofcopper were again put into each cell the solutions accurately nieasured and the current of9 pairs passed for twenty hours. ‘l’he deposit on the negative electrode was 116.3 grains ; this solution had increased in measure three-eighths of an ounce the positive had lost half an ounce ;being evaporated and crystallized the negative gave 226 graiiis crystals the positive gave 749 grains.In this ex- perinleiit we have 184grains of the salt transferred and only three-eighths of ail ounce of iiieasurable eiidostnose. 960 grains of sulphate of copper were dissolved in 20 ounces of water and put iiito the negative cell while the positive was charged with dilute muriatic acid. A battei-y of 18 pairs was connected and kept in action twenty-four hours; it was then found that the negative electrode had increased in weight 178 grains tiiicl tlie solution had gained in measure Z+ onnces. A small portion had nitrate of silver added which gave a slight niilkiiiess but not amounting to a precipitate.The whole so!u-tion of the negative cell being evaporated and crystallized gave sulpliate of copper 463 grains. This shows a transtLr ot’sul-pliate of copper from the positive solution eqml to 162 grains. r? Ihe positive solution was of a deep blue colour it had lost I)y measure 24 ounces; the electrode was covered with a white powder and had lost 212 grains. Here again the two kiiicls oferitiosmose are perfectly distinct. But we have another curious result viz. the muriatic acid apparently refusing to be tr:iiisiki*red from tlie positive to the negative solution. ‘l’his attracted particular attention and the next experiment was coiicluctecl in the following manner :-lo0 grains of sulphate of copper were dissolved and put into a small porous vessel the solution measuring 2; ounces ; this was supported at the top ofa deep glass vessel filled with dilute muriatic acid so that several inches of solution were under the porous vessel the surface of the two solutions beiiig level ; by t(iis arrangement the copper salt formed at the positive electrode by the cur-rent sunk to the hottow by its own gravity and remained un-der the porous vessel so that no transfer of salt could take Chenz.Suc. Mem. VOL.III. D Mr. J. Napier on E:lcccti*icalEudosmost. place. Two copper electrodes were used and the curreiit continued until the negative solution was exhausted of copper. When this was completed the negative electrode had gained in weight 25.1 grains the solution had increased in measure half an ounce.On testing this by nitrate of silver only a slight milkiness was obtained. The positive solution was deep blue at bottom but only a slight tinge above the bottom of the porous vessel ; the positive electrode was coated nearly to one-sixteenth of an inch with a white pasty matter a great portion had also fallen to the bottom of the vessel the elec- trode had lost in weight 132 grains. Here we have rnea-surable endosniose amounting to half an ounce without any transfer of the acid in solution. I now took two porous vessels the one charged with ounces by measure of a solutioii of sulphate of copper the other with dilute muriatic acid ; these were placed in a glass vessel filled with a measured quantity of distilled water the cells placed 1 inch apart ; two copper electrodes were used the muriatic acid cell made the positive solution the sulphate of'copper the negative.A current from 9 pairs was kept up for eighteen hours. At first the decomposition was exceedingIy slow but it afterwards increased ; the results of this experi- ment were-Positive solution lost three-eighths of an ounce pole covered with white powder and had lost in weight 37 grains; solu-tion contained sulphate of copper. The solution in the glass vessel was tinged blue by sulphate of copper had lost in mea- sure l+ ounce and gave a copious precipitate with nitrate of silver showing a transfer of muriatic acid from the positive cell. The negative cell had increased in measctre'l ;ounce.Nitrate of silver gave no indication of muriatic acid the electrode had increased in weight 26 grains. A similar experiment was again repeated the negative cell and glass vessel being both charged with distilled water the positive with dilute muriatic acid ; platinum electrodes were used. A 9-pair battery was attached for sixteen hours. The current passing was sufficient to keep deflected a galvano-nieter needle but no evolution of gas was observed till nearly the end of the experiment when the poles became covered with sriiall bubbles of gas not large enough to be evolved. The results of this experiment were positive cell lost in [Ilea-sure one-eighth of an ounce. The solution in the glass vessel was slightly acid giving a precipitate with nitrate of silver and had lost in measure 1; ounce.The negative cell had increased 2; Mr. J. Napier OTL Electrical Endosmose. in measure 1 ounce did not change the colour of blue litmus paper nor give any precipitate with nitrate of silver here also as in the last exprrimeiit we have muriatic acid being transferred in small quantities from the positive to the inter- vening liquid. But another feature preserits itself the great amount of measurable endosirlose and the almost entire absence of electrical decor~iposition ; at the sanie time the en- dosmose being principally confined to the two vessels contain- ing water as if the acid in the cell had only acted the part of a11 electrode. On reversing the condition of the last expe- riment the positive and glass vessel being charged with di- stilled water the neptive with the dilute muriatic acid 9-pair battery for sixteen hours the positive vessel lost 1; ounce; the glass vessel had increased ti ounce while the negative or acid solution underwent no alteration showing again the en- dosniose only between the two cells containing water.Several experiments were repeated both with the single and double cells having muriatic acid as the positive solution with sulphate of copper water and alkalies as the negative so-lution; in some I had transfer of acid in small quantity in others no indication of transfer; I believe the cause of dif-ference to be in the texture of the partition ;wheii R diaphragm was used less porous the enclosniose was considerable in one case amounting to 4 grains in thirty hours.Nitric and sul- phuric acids which are much more easily transferred than muriatic acid have also had their transfer resisted by two closely-textured diaphragms passing through one into the mid-division but not into the negative solutioii :however these results show that all kinds of salts or acids are not transferred with the same facility probably from their power of contluc-tion. While operating with the double cells having an acid in the positive and water in the middle and negntive cells I have several times observed that both positive and negative solu-tions increased in bulk at the expense of the middle solution ; in one iiistance the positive solution had gained I ounce the ne- gative gained three-fourths of an ounce and the middle solution lid 1ostl;ouiice.The negative and positivesolutionsoriginally contained only 2 ounces the electrodes measured 2 by i inches; ~ievertheless in these instances the transfer of the acid from the positive to the negative was considerable. The different acids gave different results of this sort; with sulphuric acid the increase was greatest muriatic acid one-half less nitric acid about one-fourth of the sulphuric ; whether this be the result of ally fixed law I cannot say the times I have ob-Dg M r. J. Nnpier 011 Ekctricrd Eridosmose. served it king too few. As I have never observed these re- sults except with the acids I am inclined to think the cause to be what lias been already stated namely the solution act- ing as the electrode thus exposing a surface of acid to water iii a state of excitement or tension suacient to attract by its exalted affinity that fluid and cause an increase of bulk in the cell in a similar manner as I shall endeavour to show in a forthcoming paper to that which caiises a greater amount of action at the positive electrode than at the negative in any electrolyte and with muriatic acid and copper as already re- ferred to in a former part of this paper amounting occasion- allvI to five times that of the negative.shall now give the results in a tabular form of a few ex- periments made to determine the relation if any between the m eas11rable en dosin ose and eI ect ri c a1 decomposition .The experiments were all made with the double cells of three compartments ; the battery used being Wollaston’s of 9-pair intensity ; the time of each experiment was sixteen hours; the electrodes of platinum. The acids used were di- luted as 1 to 25 water; solution of sulphate of copper the same strength in all. .mount of Positive Amount of deposit measura-solution. diate). 1 on decomposition. de endos-~~ ---I Ounces. I-’ Ounces Grains. SO~ Water loss + I 4 lot measurable mose. Water Water so3 + none 8 ......... ~05 Water Water L loss 3 5 ......... Water Water KO5 la gain Q none ......... HC1 Water Water 8 loss 1% 1 ......... M’ater Water I HC1 I+ gain l$ none ......... Water Water gain 8 5 1 Water Water gain + 4 10 so3cuo SO3 gain + 2 33 so3 so3 gain 6 1 P 24 SO3CuO Water loss + I 7 11 s0” Water loss 1 ~ 14 30 IICl Water loss 1; 12 27 so”cuo l03c11c loss 53 IICl IICl so3cu & gain f A-43 SO3 k.1’ate r Water lossgain 3+ loss 9 16 .?ot measurable Water Water so3 loss 1 1% evolution of gas IICl Water Water gain+ loss 1$ 1 not measurable K 0s Water Water gain & loss + + not measnrable so3 Water Water loss ij loss 3 8 riot measurable Water Water none loss 1 1 not measurable II The following table is of the same kind as the last but the time of action and the power of the battery varying as stated.Mr. J. Napier 011 Electrical Erdosmose. -Negative Loss ir Change in Gain solution. positivl glass vessel in ne Power of battery.gative Grs. lour SO3CuO none loss i'Tsoz r'i oz 21 &oz 2 2 I). large* pls. ~03cUo+z loss AOZ + 02. 12 + 02. 2 IIlttO jO3CuO none none none 23 none 2 Ditto ;O"uo ... ... ... 9 ... 2 4p. small pls. ;o CUO ... ... ... 15 ... 2 Ditto ;03cu0 ... ... ... 16 ... 2 Ditto io3cuo ... ... ... 8 ... 2 1 p. large pls. i03cu0 ... ... ... 7 ... 2 Ditto ;o"Cuo ... ... ... 8 ... 2 Ditto 103cu0 ... ... ... 6 ... 2 1p. small pls. O~CUQ' .,. ... ... 5 ... 2 Ditto 103cu0 ... ... ... 7 ... 2 Ditto ,o3cu ... loss +oz. + 02. 10 8 02. 4 Ditto O"u0 $02. gain + oz. + 02. 27 4oz. 4 9 p. small pls. * In those marked large plates the zinc plate of battery measured 6 by 4 inches ; in those marked sniall ziiic measured 2 by 2+ inches. The result of these esperiments as well as those given be- fore in detail shows that there is 110 relation between the rnea- stirable entlosmose arid the aniount of clecomposition in the cells; so that the two phaenomena must depeiid upon sonie-what different causes which now became an ohject of inquiry.Professor Faraday in his researches mentions that a current of electricity may be made to pass through soliltions without deconiposing them and Mr. Sturgeon gives it as his opinion that there is always an undecomposing current passing with a deconiposing current. These observations being applied to the results of the present inquiry into nieasurable and unmeasu-rable endosinose seemed to throw some light upon the distinct character of these pha3nomena for as will be observed the measurable endosniose seems to be greatest when the current has the greatest difficulty to pass through and when the de-coniposition is least ; and on the contrary the unmeasurable entlosmose is greatest when the battery is powerfiil and the curreilt passing fieely or rather decoinposition going on freely.In order to compare the two I now tried a few experiments with different powers ot' battery under constant circumstances as regards the clecomposition cells. Ihch division of a decom-position cell hat1 put into it 100grains of sulphate of copper dissolved in 3 ourices of water; copper electrodes were used atitl the current allowed to pass until the negative solution was exhausted of copper. The following is the mean of several trials.FI'ith a I-pair battery the negative sulution exhausted in 38 Mr. J. Nnpier OIZ Elect?-icciI E?zdosmose. forty-one hours deposited upon pole 29 grains being 3.4 grains more than the equivalent of 100 grains of sul hate which is equal to 8'5 grains of sulphate which have pas Ped by endosmose not including water of crystallization as I believe the salt passes without water. The negative solution had in- creased in bulk 1 ounce. With a %pair battery the negative solution exhausted in nineteen hours deposited upon pole 32 grains being 6*4 grains more than the equivalent of 100 grains of sulphate and equal to 16 grains of sulphate passed by eiidosmose. The solution had increased in bulk five-eighths of an ounce. With a 4-pair battery the neptive solution exhausted in twelve hours deposited upon pole 35.6 grains being 11 grains more than the equivalent of 100 grains of' sulphate and equal to 27'5 grains of sulphate passed by endosmose The solu-tion had increased half an ounce.With a 6-pair battery the negative cell exhausted in seven hours deposited upon pole 39 grains being 14-4grains more than the equivalent of 100 grains of sulphate equal to 96 grains of sulphate passed by endosmose. The solution in- creased in bulk three-eighths of an ounce. The two divisions of the decomposing cell were now charged with distilled water; two platinum electrodes were used ; the current was also made to pass through a solutioii of sulphate of copper to ascertain if suficiently strong to eflect any de- composition ; but in none of the experiments was any deposit obtained.Each experiment was continued thirty lioiirs when r the cells stood thus:- Witti one pair positive lost 1 oz. negative gained $ oz. ... two pairs ...... I oz. ... ... $ 02. ... four pairs ...... 1 oz. ... ... 6 02. ... six pairs ...... oz. ... ... 1; oz. ... nine pairs ...... 18 oz. ... ... 16 02. With these and all other experinlents with wiiter a similar vessel to the decomposing cells was placed alongside filled with water to note the loss by evaporation which in this case was three-eighths of an ounce accounting for the loss in the two cells above. A similar experiment was made with thirteen pairs of a Grove's battery the current passed four hours ; a gentle flow of gas was evolved from the electrode.No copper solution was used in this experimeut. The cells stood thus positive lost 2 ounces negative gained 12 ounce. The two divisions of the decomposition cell being again filled with distilled water into one was put a piece of zinc and into the other a piece of platinum connected by a wire; Aiiaiyis of n CoGctLt Orecfbund in IC‘estcrn Indict. 31) in tijrty-eight hours the zinc cell had lost three-quarters ofan ounce the platinum cell had gained half an ounce. This experiment was repeated many times with similar results. Two large cells were filled wiili distilled water and a piece of zinc measuring 4 hy 6 inches carefully weighed was put iiito one division and a piece of copper of the same size was put into the other division the current passed through a deli- cate galvanometer which kept deflected about 3’; the posi- tive solution was kept at a given height the negative was taken out as it increased keeping the two solutions as nearly level as possible; this was kept up for forty days when there was found to have passed through from the positive to the negative a bulk equal to 32 ounces allowing for the evapo- ration which was known by a similar vessel placed alongside.?‘he zinc was covered with a gray filrn and had increased in weig!it 12 grains; this being carefully dissolved off by am-monia water and the zinc again weighed it was found to have lost 36 grains which we inay take as the amount of oxidation during the experiment.The general conclusions which may be drawn from these experiments respecting endosmose are ( 1.) ‘l’hat the current of positive electricity passing through a liquid is always accompanied with a current oftlie liquid in the same direction. (2.) If the liquid contains ft salt or an acid that is under-going decomposition the ericlosinotic current is principally if not wholly confined to that salt or acid unaccompanied with water and therefore adds little or nottii~ig to the bulk of the liquid into which it passes. (:L) When the quantity of electricity which a battery is ca-pable of giving off is greater than the salt or acid can conduct the extra quantity if we may so term it passes through the water taking with it and thus inducing a flow of that liquid iuto the negative cell increasing the quantity ;the same effect being produced with water when no salt or acid is in solution hence the well-known fact that endosmose is greatest with pure water and even with currents that give no apparent de- coniposition or rather a decomposition so minute as to be un-observed.

ISSN:0269-3127    

DOI:10.1039/MP8450300028

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

CLVII. Analysis of a Cobalf Ore found in Western Ikdiu. By J. MIDDLETON,Esg. F.G.S. Pri?ic+al of the Hon. East India Compmy's College at Agra. BE1yG,engag.ed in analyses of the metallic ores of North-westein India with a view to the ascertainment of the constitutions of those most remarkable among them and also Mr. J. Middleton on a Cobalt Ore with the hope of detecting others whose existence in the couiitry has not heretofore been even suspected I am desi-rous of submitting to the Chemical Society the results of my iiiquit-ies whenever they appear to me of suEcient interest to justicv my troubling them with them. I may mention that should the Society desire any information from me on this or any other subject that I may be qualified and in a position to furnish I shall most gladly meet their wishes.The hilly districts of Rajpootanah are remarkably prolific inmetallic ores many of‘ these too exceedingly rich and abundant. Within a iiarrow compass in the indepdent state of Syepoore are to he found the tbllowing minerals :-Sulphuret of copper sulphate of copper sulphuret of co-balt alum. The native method of mining for the first of these ores and which is the same as that adopted for the others mag be interesting to some of’your members. 6‘ The mine of copper is very deep and difficult of access. The niiners eiiter with burning lamps on their heads and with chisels iron hammers and baskets in their hands. ’They dig out the ore with their chisels by the light of their I:tiiips aiid bring it up with great labour and difficulty to the surfhe.They then pound and grind it small in a mill after which they mix it with moist cow-dung and this mixture being made into balls is pliiced in the sun to dry. When this has beeii accomplished the Iiiunps are burnt after which they are not broker] up but being niixed with an equal quantity of char-coal and as much iron filings are put into a crucible and a strong hent kept up by blowing with a leathern bellows till the dross separates and the copper settles at the bottom iii the form of a solid disc. This product is again heated with charcoal until perfectly pure colxper is pwcluced*.” The rnineral possessing greatest interest amongst those above ei.umerated is the sulpliuret of cobalt.It is found iri the coppcv- mines in coiisitferable abuiidaiice and exists in a primitive schist in the form of bands and disseminated grains the colour of which is a steel gray inclining to yellow. The grains appear to be crystallized and are probably the cube and its derivatives. What is particularly remarkable in this ore is its purity so fir surpassing in this respect any that so far as I arn aware is to be met with anywhere else. The only suhtarice in combination with it after separation of the matrix is an irori pyrites which is however but niechanically mixed and so highly magnetic as to be readily removable by * This description is the translation of n native o:ie given to me with the minerals. foioul in IVrsfer*?rIdin. the magnet.‘I’he relative proportions in which these two exist are-Cobalt pyrites .... 90*78per cent. Iron ....... 9% ... The iron pyrites consists of black amorphous granules with-out metallic lustre and as above stated it is highly magnetic having at the same time the lorn specific gravity of 2.58. It gives 011 analysis-Iron ....... 62-27 per cent. Su I ph LI r ...... 37 -7s ... The analysis was carefidly made and repeated for verifica-tion so that notwithstanding the specific aravity is so much lower than that assigned as characteristic of?iron pyrites there can be no doubt siicti is the constitution of this constituent of tlie ore in question. ‘l’he cobalt pyrites exhibits the usuaI characteristic reac-tions generally sub,jttct to some modifications which do not tleserve notice as I tbund them to be niohtly owing to the Iiigh temperature at which my experiments were made one Iiowever is rattier rernarkzble and not sssigiiable to tliis cause but probably to the particiilar natural constitution of the iuineral wliich as I have found in other cases modifies the be1I Hv iou r of s LI bstan ces occasion a1 1y.Ferrcbcyanide of potassium produces in acid solutions a 1;lLiibh-peen precipitate which completely dissolves up in fi)rty-eight hours yovided the solution be not highly con- ceti tratecl to a brilliant emerald-green fluid which is not ;lff>cted by acids or by standing but the colour of which cl::iiiges to greenish yellow without precipitation by am-iiionia. By very careful and repeated analysis the reduction pro-cess having been adopted for the metal I found the propor-tion of the constituents to be taking the average,- Cobtilt ......64.64 per cent. Su I p h ur ...... 35.3 6 ... from which it is obvious the siil)stance is a snb-sulphuret that its constitution is Co S a rather remarkable result consider- ing that the iron coni~~ouncl doubtless of sin~iiltaneous forma- tion is different. ‘rtie cobalt pyrites has tlie specific gravity of 5*45. It is zised by Indian jewellers fi)r stniniiig .gold of‘a delicate rose-red colour; the modits opernridi wh:ch they follow I have beeii Linalde to lvarn; it is ;i secret ivith them which they are iitiwilling to dixlose.

ISSN:0269-3127    

DOI:10.1039/MP8450300039

出版商:RSC    

年代:1845

数据来源: RSC

摘要:

42 CLV111. Notes on the Prepration of Alloxnn. l3y WILLIAM &?.D., GREGORY F.R.S.E. an interesting and ahle paper on alloxan and ils de- l(N,ivatives the first part of which appears in Liebig's AN-naEen for September 2845 Schlieper enters into minute Jetails concerning the most advantageous method of preparing alloxan and after describing the results which he obtained on repeat-ing the process given by me proposes a new method of his own which he considers in every way preferable as yielding with greater facility and certainty a larger proportion of al- loxan. Professor Liebig in his Lectures (Laiicet 184.5) also recommends Schlieper's method as the best in every respect. I am still notwithstanding inclined to give a decided pre- ference to my own process when carefully performed arid that on the grounds of its superior simplicity facility and pro- ductiveness.A brief comparison of the two methods with their results will enable the reader to judge for himself. I must first of all however observe that Schlieper in re-. peating my process has not obtained results so favourable as I had formerly announced ; so that in his hands his own me- thod has been the more productive. I formerly obtained from 100 parts of uric acid 90 of crystallized (hydrated) alloxan perfectly pure not reckoning the portion of allosan remain- ing in the mother-liquids. Schlieper on the other hand from 15 ounces of uric acid treated by my process obtained in-cluding the coiltents of the mother-liquids 8 ounces hydrated alloxan 1% ounce alloxantine (= 2+ ounces alloxan) and 3 ounce parabanic acid ; in all equivalent to about 11i ounces of alloxan.This only amounts to 76 per cent.; whereas I obtained 90 per cent. exclusive of the mother-liquids which I find on an average to yield fully one-tenth more; ill all therefore at least 100 per cent. I may here state that I have never failed to obtain this as an average result since my pro- cess was publislied although I have very often repeated the process. Several of my pupils have been equally successful. I shall now therefore describe the process as I have for some time pursued it and its simplicity will I trust be evident. In my original account of' this process I recommended the use of nitric acid of sp. gr.1.3 to 1-35 and it was with such acid as I believed that my results were obtained. But as Schlieper found it impossible to succeed with acid of less sp. gr. than 1.4 to 1'42 I suspect that I may have been mis- taken as to the sp. gr. of my acid. This I cannot now ascer- tain; but it is rendered probable by the circumstance that in the experiments about to be mentioned I found an acid of Dr. Gregory or2 the Yrepuration of Alloxun. 1.412 to answer my purpose perfectly with the sahe appear- ances as I had forrnerly observed. Schlieper liaving corrected this error proceeds to describe my process as performed by him with great accuracy and niiriuteness and his description of the phenomena entirely agrees with my experience. I can only acconnt for his not obtaining such favourable results as I have always done to the circumstance of his acid being a litlle too concentrated.How-ever this may be on rending his paper I proceeded to repeat my process and obtained the results to be hereafter stated. The following is the process I now follow :-2 2; or fluid ouiices of colourlers nitric acid sp. gr. 1.412 are placed in a flat-bottomed dish or bealter glilss and as much uric acid is introduced as will lie on the point of a small spatula. This is well-stirred in to prevent the formation of lurnpfs and in a few minutes effervescence commences the liquid becomes slightly warm and the powder dissolves. More uric acid is now added taking care never to exceed a certain mall quantity and not to allow the liquid to become warm beyond a certain degree which is eayily judged of by Liying the dish on the hand.If too hot when uric acid is added or if too much acid be added at once the uniform steady effervescence is changed into a violent and tumultuous action after which no alloxan can be obtained. It is proper to have a plate with cold water at hand in which to place the dish or glass if it should seem likely to become too warni. But a little practice enables us to regulate the operation so that no external cooling is re-quired. After several portions of uric acid have been added crystals of alloxan begin to appear in the warm liquid but the addi- tion of uric acid is to be coiitinued with the same precautions till so much alloxan has been formed that OJI cooling the whole becomes nearly semisolid.Wheii this point is reached the liquid has becorne somewhat viscid and this along with the presence of the crystalline deposit of alloxan gives a pecu- liar character to the effervescence toward the end of the ope- ration. I commonly find illat with 2; fliiid ounces of nitric acid the point above alluded to is reached when about 1200 grains of uric acid dried at 21%'have been dissolved. It does riot aiiswer to operate on n much larger scale; it is better to use several dishes at once each containing 2; or at the most 3 fluid ounces of acid. For every 500 grains of uric acid 1 fluid ounce of nitric acid may be allowed. The whole is now allowed to stand all night in a cool place arid next day the alloxan is collected on a funnel with the aid of a liltle asbestus.The mother-liquid drains off and the 44 Dr. Gregory 018 the Preprt.alio?i of Alloxan. last portions of it are cautious1 y displaced by ice-cold water till the droppings are found to have oiily a moderately strong acid taste. The alloxan on the funnel which is aiihydi.ous is then digested with just as much water at 1-10' or 150° F. as will dissolve it. The solution is filtered arid 011 cooling de- posits a large crop of crystals of hydrated alloxan. [Should too much water have been added the filtered liquid must he evaporated at from 120° to 140' IT. till on cooling it crptal- lizes abundantly.] The mother-liquid of these crystals eva- porated at the same temperature yields a second crop.The mother-liquor of this is added to the acid mother-liquor previ- ously drained off and the whole liquid treated after the acltli- tion of two or three times its bulk of water with sulptiuretted hydrogen till the alloxan present is reduced to the state of alloxantine. As R part is always reduced still fiirtlier to dia-luric acid the liquid must be exposed to the air for a day or two or until it deposits no more crystals. The alloxantine is purified by solution in boiling water filtration to separate sulphur and crystallization ; and when dry three parts of it correspond to rather more than four of hydrated alloxan. If required it may very easily be converted into alloxan; as Schlieper has described this process I need not repeat it here.The mother-liquid of the alloxantine generally yields some pnrabanic acid; but very little if the process has been care-fully performed. I think it will be admitted that the above process is suffi-ciently simple. It will be observed that I no longer recom- mend the separation of tlie alloxan formed from the nitric acid in several successive portions but that there is only one operation for all in which the alloxan is collected on a tunnel with asbestus. I used sometimes to divide the process into five successive operations ant1 generally made three of them but I am now convinced that it is best to dissolve in the nitric acid the whole of the uric acid that is to be dissolved before collecti I I g tlie a11ox a 11.Let iis now consicler the productiveness of this method. I have already stated my average of former results to have been 90 per cent. of ci-jstallized alloxan exclusive of the niother- Iiqiiid which coi*responded to one-tenth more. As the pro- cess now stands we have-I. The first crop of crytals of al-loxan varying with the proportion of water usecl to dissolve the anhydrous alloxan. 2. 'l'he second crop of the same cry-stals. 3. The alloxantilie from the mother-liquid coiiverted into alloxan or calculated in that form. I take no account of the parabanic acid. Experiuient 1.-Uric acid 2600 grains ; alloxail first crop Dr. Gregory on tile Prcpnt*ntionof Alloxaii. 45 1950 grains second crop 550 grains ;alloxantine 200 grains equivalent to alloxan 290 grains.In all therefore from 2600 grains of uric acid 2790 grains of hydrated alloxan or 107 per cent. nearly. Expet-ime?d 2.-Uric acid 1 130 grains ;alloxan first CIop 800 grains second crop 140 grains ; ailoxantine 80 grains eqiiivaleiit to alloxan 116 grains. In all therefore 1056 grs. ot'alloxan lrom I 130 of uric acid or 93 per cent. Expwhent %-uric acid 1500 grains ;alloxan first crop 1150grains second crop 270 grains; ailoxantine 120 grains equivalent to alloxan 1'74 grains. 111 all therefore froni 1500 grains of uric acid 1534 grains of alloxan or 106 per cent. The above results averaging 102 per cent. of pure hydrated alloxan were ohtained without difficulty. Indeed the only delicate point in the process is the attention necessary to avoid too great a rise in temperature alloxm being decomposed by heat even when simply dissolved in water but still more when acid is present.A little experience however makes this quite easy ;and besides this difficulty attaches equally to Schlieper's new method as we shall see. The formula of uric acid being C, N4 H 0, while that of hydrated alloxan is C Nz H 01,,+ 6 aq it is obvious that 100 parts of uric acid can produce about 128 of alloxan. It is not likely that we shall ever obtain the full proportion with- out loss but I consider my process simple as it is to fiirnish a very satisfactory approximation considering the impossibi- lity of separating the whole alloxan froni the acid liquid in which it is formed. It' we now refer to Schlieper's account of his new method we find that it incliides the following operations:-l.The uric acid is acted on by hydrochloric acid and clilorate of potash care being necessary as in my process to keep the temperature below a certain point. 2. The whole of the al-loxan is redaced by sulphuretted hydrogen to the state of alloxantine. 3. The alloxantine is reoxidized by nitric acid and thus reconverted into alloxan. I cannot admit that this process is either more simple or more easy than my own. On the contrary as I obtain nine-tenths of the whole alloxan or 90 parts froni 100 of uric acid directly as alloxan and pure in the first crystallizations while Schliey~er first converts all his alloxan into alloxantine and then recotiverts the alloxan-tine into alloxan; and further as I use no other reagent but nitric acid in preparing these nine-tenths the advantage of simplicity and facility is entirely on my side.From 4 ounces of uric acid Schlieper obtains by his own 46 Dr. Gregory oii the Prepurntiou of Allo,ra?~. process CL ounces 7 drachms and 20 grains of alloxantine equivalent theoretically to 3 ounces and 7 drachms of alloxan or nearly 97 per cent. But in reconverting this alloxantine into alloxan by nitric acid it will be found impossible to ob-tain practically the whole alloxan since some of it must re. main in the mother-liquid; and moreover in the process of oxidation by heating with nitric acid some alloxan is very likely to be converted into pnrabanic acid aid thus lost.Judging from experience I should not expect the 97 per cent. of alloxan obtained in theory to yield in crystals more than 90 per cent. As far as productiveness therefore is concerned I may claim also a superiority for my method. It is true that it has not succeeded so well in the hands of Schlieper but this must I think be attributed to accidental causes and possibly to a want of perfect familiarity with the method on the part of Schlieper who seems to be so good an operator that I cannot doubt that he woujd after a little practice obtain the same results as I have always succeeded iii obtaining. Finally I beg to remind those who may wish to try my process that what Schlieper describes as a modification of my process is the process itself untnodified; because the only change introduced by Sclilieper consists in the use of acid at 1.4or 1-42instead of 1*3or 1 *35,as erroneously recommended in my original process. In point of fiict the acid which 1 have long used for the purpose hns the sp. gr. 1.412 and for this number 1.3 or 1'35 was accidentally substituted in writing or printing my former notice. In common with all chemists I am much indebted to M. Schlieper for pointing out this oversight.

ISSN:0269-3127    

DOI:10.1039/MP8450300042

出版商:RSC    

年代:1845

数据来源: RSC