Imatges de pàgina
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Chemical News, » /une 7, 1862. J

Jottings from the ExhibitionChemical Society.

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contains also what may be looked upon as some of the' most remarkable things in the building; we mean Bcrthelot's synthetical preparations. Here is " Alcohol, per syntheticam artem generatum," the union of the bicarburet of hydrogen with the elements of water. There are also stearine, and other natural organic products prepared by synthesis. Cases near this, 106, 207, and 208, cqntain some clean chemicals. The French seem to monopolise the manufacture of picric acid, some yery fine samples qf which in all conditions are exhibited iu case 191 by M. Perra. In 167 there are other fine samples of picric acid, and a specimen of azq-sulphuric acid.

The French colonial display deserves a careful inspection. Algeria would appear to be a most productive country. There are hops, some, at all events, of excellent colour, as well as some of very bad,—we cannot answer for their flavour ; several spices, opiums produced in the department of Constantine, and a small-leaved senna indigenous to Algiers, which we do not remember to have seen before. Algeria well cultivated would make France independent of half the world.

Perhaps we ought not to delay calling the attention of our readers to that part of Class j which comprises chemical utensils. On entering the Eastern Annex, the chemist will be struck by the display of crucibles (165) by the Patent Plumbago Crucible Company. The large melting-pots of the patent composition shown seem to have wonderful durability; and so do the pots of Mr. Smaile, of Newcastle (3 30), which are said to be only onefourth the cost of the plumbago crucibles. The pots of both these exhibitors are remarkably well made,—a remark which will also apply to the Cornish display by Mr. Juleff (183).

The display of chemical gloss in the English department is not remarkable. Powell's show comprises some well-made articles of good clear glass 1 the surgical glass exhibited by Mr. Wheeler (6795), comprehends a great variety of syringes; and Messrs. Kilner show some wellmade useful productions. But there is nothing in the chemical glass of our department to compare with a large retort in the Austrian (653). For size and beauty of make, this is the finest vessel of the kind we have ever seen. The rest of the articles on that stand are remarkably good.

Jottings from the International Exhibition.

Had it not been for the watchfulness of the officials, the International Exhibition would have lately stood a good chance of being burnt down on very philosophical principles. In the Japanese Court, Messrs. Baring Brothers exhibit two extraordinary quartz spheres, four or five inches in diameter, ground and polished with mathematical nioety. These spheres stood side by side on a mahogany stand in the Japanese Court, attracting but little attention from the public, until one very sunny day a visitor suddenly rushed to the office of the department with the alarming intelligence that " the two glass globes had caught fire!" The officials, on going to the spot, found the stand in a blaze, the sun having shone .directly through the globes, which, of course, acted as burning-glasses, setting the woodwork on fire. There are now two holes iu the mahogany stand large enough to insert the top of the finger. These holes are very interesting, as they are each double, showing perfeotly the double refracting properties of the quartz. The spheres have been removed into the Chinese Court, that part of the building being quite in the shade.

Every chemist should perform a pious pilgrimage to the Belgian Gallery, where he will find the two balances made by the celebrated Supre, of Brussels, and used by M. Stas in his recent researches on the atomic weights.

In the Austrian mineral department there is a most magnificent collection of several hundred perfect crystals of various salts made by M. Von Hauer, of Vienna. We hear that they have already been purchased by the trustees of the British Museum. Amongst them are several specimens of concrete crystals, illustrative of their isomorphic properties. Amongst the chemicals in this department is an interesting specimen of chloride of cscsiiim and rubidium contributed by Professor Schroetter.

The jury work has brought to the Exhibition an immense number of scientific men of eminence. During a visit to the British chemioal department a few days since, we encountered in a brief space of time MM. Stas, Fritsche, St. Claire Deville, Wurtz, Von Fehling, Hofmann, Balard, Boussingault, Payen, Persoz, Peligot, Miller, Brodie, Odling, Begnault, Forchhammer, Schroetter, Fremy, and many others who constitute the aristocracy of science.

The specimensofplatinum.iridium, osmium, ruthenium,

Salladium, silicon, boron, and many other rarities cxibited by Messrs. Johnson and Matthey in Class 1, are well worth close examination. A mass of melted platinum, weighing nearly 2 cwt., is the gem of the collection. It was lately fused at the laboratory of Messrs. Johnson and Matthey by M. St. Claire Deville, who, we regret to hear, has been suffering severely from the effects of the fumes of osmic acid given off during the process.

PROCEEDINGS OF SOCIETIES.

CHEMICAL SOCIETY.
Thursday, May 29, 1862.

The Masteh. Op The Mint in the Chair.

A Papeb, by Dr. W. Cbum, "On the Action of Mordants in Dyeing," was read by the Secretary. It had been supposed that a combination of a chemical nature took place between the fabric and the dye stuff or mordant, but this appeared to be erroneous; on the contrary, in those cases in which the dye was fixed without a mordant, the attraction was simply cohesive, and similar to that exerted by all extended surfaces. The structure of the fibre bore out this view, for on examining cotton under the microscope it was seen to be composed of flattened tubes with translucent walls which were permeable to fluids, and these acted in the same manner as any other porous structure, such as charcoal, &c. When mordants were used, they were often deposited within the fibre and retained there mechanically, and afterwards, hy combining with the dye, served to fix this in the material. This explanation was rendered more probable from the fact that dead cotton did not take the dye. The dead cotton, which was found occurring in small quantities in company with the ordinary material, seemed to consist of fibre which had been imperfectly formed; under the microscope, it was seen to have no central tube, and was so transparent as to be almost invisible; this accounted for its refusing to absorb the dye. An example of an attraction between the fibre and the dye was afforded by a solution of reduced indigo; when a piece of cotton was immersed in such a solution it absorbed a certain quantity into its substance, and this, on exposure to air, became blue; by immersing successive pieces in the same solution the whole of the indigo might be removed. Tannic acid was attracted in

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the same manner by the fabric, and this, when immersed in a solution of binoxide of tin, combined chemically with it and fixed it in the cloth, and the binoxide of tin afterwards acted as a mordant. When acetate of protoxide of iron was employed, the oxide of iron was deposited in the fibre and held there mechanically, and afterwards combined with the dye stuff. In some cases the mordant and dye could both be applied at the same time, but it was necessary that both should be in solution.

The Chairman remarked that it was a circumstance worthy of notice that the mordants were all colloids.

Mr. Malonk said that he had lately examined the properties of precipitated gold, which was known to remain for a long time suspended in water, and had found that the fungus that sometimes grows in distilled water had an attraction for it, and collected it gradually on its surface; also that when the precipitation was made in an ethereal solution the subsidence of the precipitate took place readily, from which he had concluded that the precipitate possessed properties analogous to those of colloids, and that ether had the power of coagulating it.

The next Paper was by Professor Bloxam, " On the Capacity of Arsenious Acid for Bates, and on tome Arsenites." Arsenious acid was usually considered bibasic, but the experiments he had made tended to show that it could neutralise three equivalents of base. He first determined the amount of carbonic acid set free by arsenious acid from alkaline carbonates, and found that at a temperature of 212T., if the arsenious acid were in excess, two equivalents of arsenious acid displaced one equivalent of carbonic acid; but with excess of the carbonate, one equivalent of the acid displaced two-thirds of an equivalent of carbonic acid. At a red heat a similar result was obtained with excess of acid, but with excess of base one equivalent of carbonic acid was displaced. The action of the acid on the hydrates of the alkalies was next investigated; but under these circumstances the acid was oxidised, hydrogen being evolved. Salts were then prepared by mixing solutions of arsenious acid and alkalies; in this manner the crystalline salt, KO,IIO,;As 0,4 Aq, was formed; the water of crystallisation could be driven off at 2i2°F., and at a higher temperature the remaining water disappeared, and a biarsenite remained in a beautifully transparent state. A scsqui-arsenite, 2KO,3AsO, +3IIO, and the corresponding soda salts, were obtained in a similar manner. The silver salt was tribasic, amorphous when first precipitated, afterwards becoming crystalline. There were three lead salts, a monobasic and bibasic salt, and a third which was obtained from an acid solution and had the composition, 3PbO,3HO,2 As 03. The zino salt was tribasic, even when deposited from an acid solution, and under the microscope was seen to consist of a number of spheres. The magnesia salt, 2Mgo.HO, As O., + Aq, the copper salt, 2Cu0,H0, As O,, and the baryta salt, BaO,2H0, As O „ had also been prepared.

Mr. Gladstone then read a paper " On the Reciprocal Decomposition of Salts in Solution." The question he had endeavoured to decide was, whether, when two salts which might be represented by the formula;, M R and M' R', were mixed, the same result was obtained as with M' R and M R'. To determine this, salts were mixed in which the resulting change caused a difference in colour, and in these cases no difference could be detected in the resulting mixtures; in some cases a coloured salt was added to the resulting mixture, and the change in colour observed. Dialysis was also employed, and from the results it was concluded that if a sufficient time for the rearrangement of the bases and acids was allowed, no difference could be detected in the resulting mixture. To determine quantitatively the amount of decomposition the polariscopc was employed, and the substances which suggested themselves as appropriate for the purpose were nicotine and tartaric acid; the salts of nicotine do not rotate the plane of polarisation so much as the base itself, and a mixture of

nicotine with chloride of ammonium had a greatly diminished power of rotation; with chloride of sodium the decomposition was not so great, and the quantitative determination was very decisive. Tartaric acid, however, did not give satisfactory results, but no doubt other substances could easily be found for the purpose.

The next paper was by Mr. Riley, " On the Presence of Titanic Acid, and Means of Determining Iron, in Clay." From an examination of many samples of clay he had come to the conclusion that titanic acid was always present in this substance; in the ordinary method of analysis the titan ic acid was sometimes left with the silica, at other times it passed into solution and might be separated by neutralising, boiling with sulphurous acid, and fusing the resulting precipitate with bisulphite of potash. The iron could not be accurately determined by precipitation by potash, for other matters were carried down and increased the weight of the precipitate; standard solutions, either of bichromate or permanganate of potash, were preferable. He had found that in all cases in which the blast furnaces produced good iron, titanium was present.

A new maximum and minimum mercurial thermometer was exhibited by Mr. W. Simmonds. It consisted of a lube bent upon itself so that the two portions were parallel; each end being terminated by a bulb. One of the bulbs and a portion of the tube were filled with mercury, and upon this some sulphuric acid was placed; two little floats were immersed in the sulphuric acid, one of which was placed in contact with the mercury, the other just beneath the surface of the sulphuric acid; the first acted as the maximum, the second as the minimum index; the instrument was arranged so that the two limbs were horizontal.

NOTICES OF PATENTS.

Grants of Provisional Protection for Six Months.

281. Marc Antoine Francois Mennons, Rue de l'Echiquier, Paris, "Improved processes for the recovery of the oleic acid contained in the residual scouring waters of woollen and other textile materials or fabrics."—A communication from Edmond Lepainteur, Oallard, France.— Petition recorded February 1, 1862.

1222. Lachlan McLachlan, Manchester, "Improvements in governing or regulating light used for taking photographic portraits and other photographic pictures, part of which improvements is also applicable to lighting picture galleries."

1232. Francis Gybbon Spilsbury and Frederick William Emerson, Stratford, Essex, "Improvements in the treatment of fusel oil, and for various applications of the same to useful purposes."

1242. John Fletcher, Farnham Place, Southwark, Surrey, "Improvements in the apparatuses for treating saccharine liquids."—Petition recorded April 28, 1862.

1288. William Bickford Smith, Camborne, and William Bennetts, Tucking Mill, Cornwall, "Improvements in the method of, and apparatus for, preventing the injurious effects occasioned by smoke, sulphur, and the deleterious gases which escape from stacks, chimneys, cilcining nouses, chemical and other furnaces."—Petition recorded May 1, 1862.

451. Emil Moritz Stoehr, Manchester, "Improvements in the manufacture of manganese, and in the combinations' of manganese with other metals."—A communication from Oscar Eugen Prieger and Ferdinand Carl Prieger, Schloss Gereuth, near Ebern, Bavaria.—Petition recorded February 20, 1862.

714. Constantino Nicolaus Kottula, Bell Isle, London, "Improvements in the manufacture of combined soaps." —Petition recorded March 15, 1862.

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1038. Andrew Trimcn, Adam Street, Adelphi, London, "The protection and solidification of magnesian limestone and other stones, and for the prevention of the passage of water through the same."—Petitions recorded April 10, 1S61.

1105. Matthew Cartwright, St. John's Row, Hoxton, London, "Improvements in the manufacture of models, and of plates or pieces for artificial teeth, and in combining or amalgamating india-rubber and gutta-percha with metals for the manufacture of artificial plates or pieces, and for other purposes."

j 115. Charles Denton Abel, Southampton Buildings, Chancery Lane, London, "Improvements in the manufacture and production of the chromates and the bichromates of potash and of soda."—A communication from Louis Alexandre Taillandier, Argenteuil, France.

1118. William Hodgson Hutchinson, Bury, Lancashire, "Improvements in the manufacture of ammonia or its salts, and cyanogen or its compounds, from refuse gluten." 1127. Charles Denton Abel, Southampton Buildings, Chancery Lane, London, " Improvements in the manufacture and production of certain alloys containing cadmium." —A communication from Henri Catherine Camille du Ruolz and Anselme Louis Marie Fontenay, Paris.

1137. Edwin Dove, Hunter jkreet, London, " Improvements in matches and fusees, and apparatus for containing and igniting the same."

50. Louis Wunder, Leignitz, Prussia, "Improvements in the manufacture and composition of soap, applicable especially for shaving."—Petition recorded January 8, 1862.

139. Thomas Roberts and John Dale, Manchester, "Improvements in the manufacture of gunpowder."— Petition recorded January 18, 1862.

1177. William Moir, Manchester, "An improved instrument for ascertaining the specific gravity of liquids."

1195. William Denny Ruck, Duke Street, London Bridge, "The manufacture of grease from coal, tar, coal oil, creosote, or dead oil."

1217. Charles Reed, Kintbury, Berkshire, "A new method of treating the sorghum saccharatum or holcus saccharatus in order to obtain saccharine liquor and pulp therefrom."

1231. Squier Cheavin and George Chcavin, Boston, Lincolnshire, "Improvements in filtering and purifying water, and in apparatus employed therein."

1235. Gustav Bischof, jun., Swansea, "Improvements in treating solutions containing copper and silver, or either of them, to obtain metallic copper and silver."

1304. Alfred Vincent Newton, Chancery Lane, London, "Improved electrical apparatus applicable to the lighting of gas."—A communication from Robert Cornelius, Philadelphia, U.S.—Petitions recorded May 2, 1862.

1332. Christopher Binks, Parliament Street, Westminster, "Improved methods of obtaining hydrogen gas and certain gaseous compounds of hydrogen and of carbon."

1350. John Henry Johnson, Lincoln's Inn Fields, London, "Improvements in the manufacture and production of minium or red lead."—A communication from Charles Louis Pierre Burton, Rue St. Sebastien, Paris.

1352. John Henry Johnson, Lincoln's Inn Fields, London, "Improvements in the manufacture of soda and potash, and of their carbonates."—A communication from Charles Louis Pierre Burton, Rue St. Sebastien, Paris.

1366. Richard Archibald Brooman, Fleet Street, London, "An improved box and apparatus for containing and igniting matches."—A communication from Louis Leonard Poulain, Presles, France.

1378. William Southwood, Kensington, Middlesex, "Improvements in machinery for pulverising ores and extracting metals therefrom, part of which is applicable to breaking stones."

1188. William Edward Newton, Chancery Lane, London, "An improved fertilising composition."—A communica

tion from John McAuley Gallacher, Roxbury, Norfolk, Massachusetts, U.S.

Notices to Proceed.

627. William Noy Wilkins, St. John's Wood, Middlesex, "Improvements in the manufacture of pigments for oil and water colours."—Petition recorded March 8, 1862.

28. James Whittou Arundell, Gresham House, Old Broad Street, t>ondon, "An improved method and improved apparatus for treating and dressing ores and minerals, particularly applicable to tin, lead, copper, zinc, and iron ores."—A communication from Martin Nueburg, Ealk, Rhenish Prussia.

150. John Stcnhouse, Upper Brunswick Terrace, Barnsbury Road, London, " Improvements in the protection of metallic surfaces, and in rendering certain substances less pervious to air and moisture."

281. Marc Antoine Francois Mennons, Rue de l'Echiquier, Paris, " Improved processes for the recovery of the oleic acid contained in the residual scouring waters of woollen and other textile materials or fabrics."—A communication from Edmond Lepainteur, Gallard, Longeron, France.—Petitions recorded February 1, 1862.

378. Marc Antoine Francois Mennons, Rue de I'Echiquier, Paris, "Improvements in the disinfection of animal excretions, and in the extraction therefrom of fertilising elements for agricultural purposes."—A communication from Alfred Marie Celestin Edgard Goussard, Rue d'Enghein, Paris.—Petition recorded February 13, 1862.

58. Henry Cook, Manchester, "An improved mode of, and apparatus for, transmitting despatches and small articles by the agency of electricity."—A communication from Gaetano Bonelli, Milan, Italy.—Petitions recorded January 8, 1862.

59. Charles William Siemens, Great George Street, Westminster, "Improvements in the means and apparatus employed for insulating and protecting telegraph conducting wires, and in apparatus for working the same."— Partly a communication from Dr. Werner Siemens, Berlin, Prussia.—Petition recorded January 9, 1862.

123. Thomas Myers, Bloomsbury Square, London, and Edward Myers, Millbank Street, Westminster, "An improved composition for preventing rust on bright steel, iron, brass, or metal."—Petition recorded January 17, 1862.

220. Arthur Herbert Church, Great Portland Street, St. Marylebone, Middlesex, " Improvements in the means of preserving stone, brick, slate, wood, cement, stucco, plaster, whitewash, and colour-wash from the injurious action of atmospheric and other influences, also in the application of colours to the surfaces of stone, brick, slate, wood, cement, stucco, mortar, clay, plaster of Paris, whitewash, and colour-wash, and in the retention of such colours thereon."—Petition recorded January 28, 1862.

235. William Clark, Chancery Lane, Loudon, " Improvements in the disintegration and bleaching of textile materials for the manufacture of paper."—A communication from Jean Baptiste Michel Auguste Siry, Boulevart St. Martin, Paris.

338. Mark Antoine Francois Mennons, Rue de l'Echiquier, Paris, "Improvements in the treatment of coprolites, and other fossil phosphates of lime."—A communication from Guillaume Louis Edouard Buran, and Louis Goupy, Rue du Grand St. Michel, Paris. — Petition recorded February io, 1862.

304. Alfred Vincent Newton, Chancery Lane, London, "Improved electrical apparatus applicable to the lighting of gas."—A communication from Robert Cornelius, Philadelphia, U.S.—Petition recorded May 2, 1862. Invention Protected for Six Months by the Deposit of a Complete Specification.

1244. William Taylor Glidden, Massachusetts, U.S., "A new and useful mode of restoring phosphatic guano." —A communication from Louis Harper, Brooklyn, New York, U.S.—Deposited and recorded April 29, 1862.

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CORRESPONDENCE.

Downing v. Chance. , To the Editor of the Chemical News. Sir,—A friend has directed my attention to a passage in the Chemical News of May 17, where, speaking of chemical manufactures and noxious vapours, you say :— "We have seen recently that when they have taken every precaution it leaves them quite at the mercy of wonderful chemists, endowed with marvellous vision, who see bluish vapours rise whenever they place on the ground, within sight of a soda factory, a piece of filtering paper soaked in ammonia." You go on to speak of Messrs. Chance, from which I infer that you allude to the evidence given in the case of Downing v. Chance, and as I was one of the witnesses who saw and examined the vapours alluded to, that I am one of your " wonderful chemists."

As regards the insinuation of animosity towards Messrs. Chance, I beg to state that ever since I have been engaged in my present office in Birmingham I have been in friendly communication with the Messrs. Chance and many of their family connections, and have received from them so many marks of courtesy and kindness, that such conduct as you impute to me would have been grossly ungrateful as well as unjust 1 that, instead 0/ the feeling which your words imply, I entertain the greatest respect and regard for those gentlemen, both as private individuals and as manufacturers, and I consider their chemical and their glass works as about the best conducted in the Kingdom, I hesitated for some days before consenting to give evidence on this trial, and, in the mean time, consulted some mutual friends, and ascertained by very careful investigation what was the character of the plaintiff, and whether there was any possibility of the case being made up for annoyance sake, or with the view of getting heavy damages, or anything of that sort, and it was only when I learned that Mr. Downing was only seeking fair compensation for the amount of damage suffered somehow that I went into the chemistry of the matter, to ascertain how far the damage was traceable to the fumes from Messrs. Chance's works.

As regards the "marvellous vision," every chemist knows the reaction of hydrochloric acid upon ammoniacal vapours.

Thirdly: I need only state that the very important point as to the position in which I stood when making my experiments, its relation to the stacks, the direction of the wind, the deflecting influence of the mound of waste, nnd the relative positions of other factories, were very properly made the subject of a most rigid cross-examination by the defendant's counsel, Sergeant Pigot. The cross-examination on these points lasted about three-quarters of an hour, and resulted not only in the full and further confirmation of the accuracy of my experiments, but led to some very strongly complimentary remarks being made upon my evidence by Mr. Huddleston in his address to the jury.

I hope, Sir, that since you have so freely and lightly brought my name and my evidence before your readers, nnd have done me much injustice thereby, you will insert this letter. I shall also be much obliged if you will explain wherein lies the "curiosity" of my evidence on the trial, Downing v. Chance.

As regards that on the other trial, I am not at all surprised that you should think it curious if you believe in the accuracy of the report which you published. As you prefaced that report with an expression of your own doubts as to its accuracy, I took no notice of it at the time, especially as I had made some notes for a paper upon nn unexpected reaction which I had stumbled upon in the course of my examination of gas water. The peper was intended for your pages, and would have fully explained the curious part of your report of my evidence; but as you made a second attack upon my evidence which

could not be explained by a technical error of a newspaper reporter, I refrained from becoming a contributor to a journal in which I had been thus treated.—I am, Sec.

W. Mattieu Williams. Hall Road, Handsworth, near Birmingham. [We print as a matter of course all that is pertinent in Mr. Williams' letter. He is quite wrong in construing our remarks into a personal attack. The observations we felt bound to make on the evidence given on the trials alluded to were made solely in the interest of true science, and they contained no insinuations against Mr. W.'b perfect good faith; nor does anything we have written convey a hint that he has wilfully sought to injure the Messrs. Chance, to whom we are perfect strangers. The reports, as we said at the time, were taken from local papers, and we could not be answerable for their verbal accuracy; but on one point they have been fully confirmed by the circuit short-hand writer's notes. We shall be glad to be the medium of conveying to our renders any account of the circumstances which determine the formation of bluiah vapours when ammonia and hydrochloric acid come in contact with each other; and also pleased to publish a description of the unexpected reaction stumbled upon by Mr. W. in his examination of gas water.—Ed. C.N.]

MISCELLANEOUS.

■loyal institution Tuesday, June 10, at Four

o'clock, the Rev. G. Butler, M.Al, "On the Art of the Last Century ;" Thursday, June 12, at Three o'clock, Dr. Lyon Playfair, C.B., "On the Progress of Chemical Arts (1851-1862)1" Friday, June 13, at Eight o'clock, MajorGen eral Sir H. Kawlinson, "On Cuneiform Writing, and the Way to Read it;" Saturday, June 14, at Three o'clock, Professor Anderson, M.D..F.R.S.E.," On Agricultural Chemistry."

Royal Imttltntion of Great Britain.—General Monthly Meeting, Monday, June 2, 1862.—The Rev. J. Barlow, M.A., F.R.S., Treasurer, in the chair.—Mrs. Henry Bischofsheim, the Rev. W. R. Tilson Marsh, M. A., and Major Roger North, were elected Members of the Royal Institution. The presents received since the last meeting were laid on the table, and the thanks of the members returned for the same.

PotauilUation of Srn-waler l»y the Electric Current.—In Macmillan's Magazine for this month is an interesting paper by Dr. Phipson, entitled, "Electricity at Work," in which the author passes in review the useful applications of this wonderful agency. He concludes his paper as follows :—" Reflecting upon the powerful decomposing chemical force with which we are furnished by the electric current, it occurred to me that I might be able to render sea-water potable by decomposing and extracting its salt, by means of a moderately powerful battery. The experiments were made at Ostend a few yearB ago. My apparatus consisted of three vessels containing sea-water; the centre one contained the water to be operated upon, the two others communicated with the two poles of the battery. The three vessels were connected by two bent fl-tubes filled with sea-water. As the only battery I could procure in Ostend was rather weak, I passed the current through the water for about fourteen hours, after which one of the outside vessels hnd become acid and the Other alkaline. The sea-water was then filtered through charcoal, and was nearly drinkable. It would have been, I doubt not, quite potable had the battery employed been more powerful, as it was I found it difficult to extract the last particles of salt; and the water, after subsequent trials, still presented a slightly brackish taste. I have not had an opportunity of repeating this experiment since, but from the results obtained, I think it probable that senwater may t>e rendered potable by means of the electric current."

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SCIENTIFIC AND ANALYTICAL
CHEMISTRY.

On some Cyanides of the Platinum Metals,
by M. C. A. Maktius."

The residuums from the treatment of platinum ore are submitted to the following operations to isolate the metals they contain:—

After pulverising and levigating to separate the larger grains of osmidc of iridium, slightly calcine the powder in a closed crucible; then mix with it one part of finely granulated lead and one part half of litharge, and melt at red heat in a thick iron crucible. The lump of lead, freed from the adherent scoria, treat with nitric acid diluted with one and a-half times its volume of water. The residuum consists of iridium, rhodium, ruthenium, in the form of black powder, and osmide of iridium in spangles separable by levigation. Melt tho osmide of iridium with some zinc in a charcoal crucible, heated until the zinc becomes volatilised; the osmide, remaining as a black powder, heat to redness in a current of oxygen to eliminate the osmium. Collect the osmic acid in a well-cooled receiver.

Mix the residuum of this calcination, together with that from the action on the lead, with their weight of chloride of sodium, and treat with chlorine according to M. Wohler's method. Add hydrochloric acid to the solution and a quarter its volume of nitric acid, then distil until it is reduced to a third. The osmium disengages itself in the form of osmic acid, and is condensed in ammonia. The osmium is then easily extracted from the solution of osmiate of ammonia by evaporation and calcination with hydrochloiate of ammonia. The osmium remains under the form of a blue-black powder.

Precipitate the solution whilst warm by hydrochlorate of ammonia. After letting it stand for a few days, decant the supernatant liquid; it will be found to contain traces of iridium, rhodium, and gold. Wash the precipitate with a saturated solution of a salt of ammonia until it ceases to impart a red colour. The washing will contain all the rhodium.

The residuum, formed of double chloride of iridium and ammonia, mixed with double ammoniacal chlorides of platinum and ruthenium, melt with one and a-half times its weight of cyanide of potassium in a porcelain crucible. The chlorides become transformed into cyanides in 10 or 15 minutes. Pour the melted mass on to a porcelain plate, and dissolve it in the smallest possible quantity of water. To the warm solution add sufficient hydrochloric acid to decompose all the free cyanide of potassium, and then precipitate with sulphate of copper. Wash the violet precipitate, formed principally of platino

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cyanide and iridio-cyanide of copper, in boiling water, and decompose with a boiling solution of caustic baryta.

The double barytic cyanides contained in the solution are easily separated by crystallisation. The platinocyanide is much more soluble with heat than with cold, and crystallises before the iridio-cyanide, which is whito and easily distinguished from the platino-cyanide. Small quantities of ruthenio-cyanidc of potassium are found in the mother-waters of the iridium salt.

Cyanide of 0*miuiu.—By heating concentrated hydrochloric acid with one of the osmio-eyanides to be hereafter described, a very stable dark violet precipitate of cyanide of osmium, OsCy, is thrown doivn, hydrocyanic acid at tho same time being disengaged.

11»<i ru-inwiii-crauH' Acid.-—Saturated solution of osmio-cyanido of potassium mixed with its volume of fuming hydrochloric acid deposits white flakes of hydroosmio-cyanic acid, OsCy a CyH. These flakes, collected on a filter, washed in concentrated hydrochloric acid, and then dissolved in alcohol, separate into beautiful anhydrous prismatic crystals, when a layer of ether is poured on the alcohol. When they are dry the air has no effect on them; but when they are moist the air decomposes them, forming cyanide of osmium. They are soluble in water and alcohol. They have a strong acid reaction on test paper, and displace carbonic u.-id from carbonates.

Oamio-cyunlfle of Potaiwiain, which has been already described by M. Claus (Repertoire de Chimie pure, vol. iii. p. 121), presents a remarkable analogy to ferro-cyanide, even in the particularities of the action of its crystals on polarised light. The most simple method of preparing it consists in treating osmiate of potash by cyanide of potassium, evaporating the solution and heating the residuum without melting it in a porcelain crucible. When the mass is white it should be taken up by boiling water, filtered, and crystallised.

Osmio-cyanide of potassium is almost entirely soluble in boiling water and insoluble in alcohol and ether. Its crystals belong to the right prismatic with square base.

The action of weak nitric acid on this salt occasions a brisk disengagement of gas. The solution seems to contain a nitro-osmio-cyanide.

As yet it has not been found practicable to obtain with osmium a salt corresponding to ferricyanide of potassium.

Further, the author describes osmio-cyanide of barium OsCy.2BaCy + 6IIO), double osmio-cyanide of barium and potassium (2OsCy.2BaCy.2KCy + 6110), and a magnificent violet precipitate, which was produced by adding a salt of peroxide of iron to the osmio-cyanide of potassium, and which is probably a ferric osmio-cyanido (30sCy.2Fe2Cy3 + xHO). He mentions the existence of various other osmio-cyanidca and of an osmio-hydrocyanic ether.

Cyanides of ruthenium nro exactly analogous to cyanides of osmium.

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