Obrazy na stronie
PDF
ePub

wax.

CHEMICAL News, 172 Chemical Notices from Foreign Sources.

April 18, 1879. space-filling power of one stere, though there occur, e.g., prossed, and sublimed. (2.) The mother-liquors are in water of hydration =H10{, certain condensations or treated with sodium sulphite or bisulphite till the precipi. expansions of individual elements which, as will subse- tated iodine is converted into hydriodic acid, which is quently appear, are characteristic of organic nuclei. A then precipitated as cuprous iodide by a solution of copper second very remarkable fact is the extraordinary constancy sulphate and sodium sulphite. (3.) The iodine in the of the voluminar constitution with which certain elements mother-liquors is concentrated by fractionated evaporation and their compounds are contained in the most different and crystallisation, and the iodine, mixed with a proporgroups. A third very important fact is the simplicity of tionate quantity of sodium sulphite or bisulphite, is rethe volume-molecules of all salts. Their volume-mole- covered by distillation from the acidified liquid. cules are almost always monatomic, or at most di-atomic, Efficacy of Compounds Employed as " Antithe latter being the case only in iron spar, calcareous chlore." - Dr. G. Lunge. The author has submitted the spar, and sodic nitrate.

modus operandi of some of these agents to a critical ex

amination. The hyposulphite of soda (now thiosulphate) Die Chemische Industrie.

was said by Fordos and Gélis to undergo a direct conNo. 1, Jan., 1879.

version into sulphate. Its rea&tion with chlorine, as well Manufacture of Potassium Iodide.-E. Schering.- not at once washed out, attacks the iron of the machinery,

as that of the sulphites, gives rise to free acid, which, if Inserted elsewhere.

forming injurious salts which render the paper brittle, Process for the Extraction of Sulphur from Alkali- yellow, or spotty. There is no sufficieot proof that the waste, Gypsum, Heavy Spar, and Sulphurous Acid, use of hyposulphite leads to the deposition of sulphur and and recovery of the Earths previously Combined the formation of acids by its gradual oxidation if the with Sulphur in the State of Carbonates.-Max half-stuff has been properly washed. The efficacy of Schaffner and W. Helbig.—This process cannot be fully hyposulphite is much less than has been assu ned. Am. described without the accessory plates. It is based upon monia as an antichlore appears to act only at an elevated the decomposition of calcium sulphide and magnesium temperature with the emission of an unbearable odour. chloride, which latter salt has no action upon calcium carbonate. The residue from this reaction, after the expulsion of the sulphuretted hydrogen and which contains

Chemiker Zeitung. magnesia and calcium chloride, is exposed to the action of

No. 12, 1879. carbonic acid, when magnesium chloride is reproduced and calcium carbonate formed.

Adulteration of Wax.-Dr. Max.- Bee's-wax is often

sophisticated to the extent of 33 to 50 per cent with No. 2, February, 1879.

ceresin, a mixture of refined earth-wax and caranaubaReport on the Stassfurt Industry.—Dr. B. Bernhardi.

Pure bee's-wax has a higher specific gravity (0-94 -The improvements recently introduced aim chiefly at

to o'97) than these ingredients or than the mixtures, effecting economy in the consumption of carnallite and of which range from 0-876 to 0-937: Prof. v. Wagner recomfuel. li is proposed to evaporate the various liquors in mends the sample to be placed'in dilute alcohol of sp.gr. closed boilers under a slight pressure.

Continuous 0-945, and rejected as impure unless it Aoats.-Dingler evaporation is likewise suggested, the difficulty being the Polyt. Journal. removal of the salts from the heated surfaces as deposited.

Detection of Starch in Milk.-Dr. Vulpius coagulates The conversion of potassium chloride into sulphate by the sample with a few drops of acetic acid, heats to a boil, double decomposition with Epsom salts is advantageously filters, and adds to the clear whey an aqueous solution of effe&ted under Dr. Borsche's patent. The mixed salts iodine, which at once produces a blue cloud if starch be are successively lixiviated with quantities of water in present; 5 milligrms. were thus distindly recogaised in sufficient for complete solution. The bulk of the mag. 5 c.c. of milk.-Pharm. Zeitung. nesium chloride is removed in the first liquors. Many Chloride of magnesium is recommended as a fluid for practical men, however, still prefer to treat the potassium filling wet gas-meters. chloride with sulphuric acid in a Jones salt-cake furnace. Action of Magnesium Chloride upon Steam Boilers

No. 13, March 27, 1879. with reference to the Magnesia Process of Purifying Distillation of Coal-tar.-The author gives an account Feed-water.-E. Bohlig.-The author concludes from of the distin&ions between the products obtained by the his experiments that magnesium chloride has no corrosive dry distillation of wood, peat, lignite, and coal, and shows action as long as a slight excess of magnesium carbonate that according to the recent experiments of Letny, Lieberis present.

mann, and others, wood-tar and petroleum-tar, &c., if No. 3, March, 1879.

passed through ignited tubes, yield the same products as Meeting of the Association for Promoting the coal-tar, which he considers may be of great importance Interests of German Chemical Industry.-In à peti- for the production of the aniline

and alizarin colours. He tion to the Reichstag concerning the use of alleged then gives an account of the distillation of coal-tar with poisonous colours, the Association point out that certain especial reference to anthracen. dyes, such as red corallin and aurantia, denounced as At Dortmund, on March 22, Dr. Schridde delivered a poisons, have subsequently been proved perfealy innocent. lecture on "Chemistry as a Trade, an Art, and a Science." They pray that no colour may be prohibited till it has In Switzerland the factory inspectors receive a yearly been formally pronounced dangerous to public health by salary of 6000 francs, with an addition of 7 francs daily a commission of specially qualified chemists and physioló- for their expenses when travelling on official business and gists after a due scientific examination. At the sessions 5 francs more if detained over night. of February 23, 24, and 25 a long debate ensued on the prote&tive duties to be imposed on foreign chemicals, and a tariff was agreed upon to be submitted to the Reichstag. South American Production of Iodine.--Dr. G.

Moniteur Scientifique, Quesneville. Langbein. The processes in use for separating iodine

February, 1879. from the mother-liquors of the nitre refineries may be This issue is almost entirely taken up with a transla. divided into three classes. (1.) The liquors, without tion of Sir B. C. Brodie's well-known * Chemical Cal. previous concentration, are mixed with a quantity of culus," a continuation of the discussion between MM. sodium sulphite corresponding to the iodine present, the Berthelot and Pasteur, a notice of foreign chemical iodine separated out is filtered tbrough linen bags, washed, researches consisting entirely of extra&s from the Berichte

April 18, 1879.
}
Meetings for the Week.

173 der Deutschen Chem. Gesell., an account of the recent Friday, May 23.-W. H. Preece, M.R.I. Multiple great discovery by Mr. Norman Lockyer, and a very | Telegraph, or Duplex and Quadruplex Telegraphy, lengthy notice of a work on applied physiology by M. Friday, May 30.-Grant Allen. The Colour-sense in L. Figuier.

Insects; its Development and Reaction. Detc&ion of Tarry Matters in Ammonia.—The Friday, June 6.- Professor Dewar, M.A., F.R.S. well-known nitric acid test is recommended, which, in Friday, June 13.-Frederick J. Bramwell, F.R.S. The presence of aniline, toluydin, &c., gives a gooseberry-red

“ Thunderer” Gun Explosion. colour.

Another Agricultural College. A correspondent of Ethyl-green and Malachite Green.-Another Swiss The Live Stock Fournal writes as follows :-"With con. firm, MM. Gerber and Uhlmann, of Bale, announce that siderable satisfaction I learn that the starting of another their green colour is prepared by the reaction of the Agricultural College is already under contemplation, for it hydride of benzoil upon ethyl- or methyl-aniline, and that has long been evident that the Cirencester institution has it does not fall within the limits of the patent for "mala- neither attained the position which its promoters had in chite green."

view, nor conferred on the agriculture of the country the benefits which were reasonably expected from it. I hail

therefore with pleasure the intimation that the four Archives Neerlandaises des Sciences.

leading professors at Cirencester, viz., Professors Church, Tome xiii., 4me Livraison.

Tanner, Fream, and Sheldon, having been requested by

influential Researches on Quinamin.-A. C. Oudemans.- The ducing to form the scheme of a second Agricultural

persons to consider the idea, are already reauthor first gives the analysis of the crude mixture of College, for which, I have no doubt, they will receive a!! alkaloids known as quinetum, which he finds coinposed the help and patronage that are necessary to bring their of:Cinchonin

project into successful operation. There is, indeed, room

37'0 Quinin

6:1

for several agricultural colleges, and no doubt the CirenCinchonidin

cester one would have had a better tale to tell if two or

22'9 Quinamin

three rival establishments had existed to spur it on. I

4'5 Amorphous alkaloids

regard the starting of a second Agricultural College in Carbonate of soda..

England as an event that is calculated to do a inuch.

2'9 Water

needed service to the parent institution, and I venture to 297

predict that each of the two colleges will do better than From this mixture be separates quinamin, C19H24N202, the single one has hitherto done, provided the Council the properties, reactions, and salts of which he describes will seriously take in hand those changes which are in detail.

evidently so much needed at Cirencester."

2I'I

.

Les Mondes, Revue Hebdomadaire des Sciences.
No. 11, March 13, 1879.

NOTES AND QUERIES.
This issue contains no original chemnical matier.

Honey.-Can any of your readers give me references to any late (within ten years) investigations of the chemical composition of honey 1-E. H. S.

Insurance of Tar Distilleries.-Can any of your readers give MISCELLANEOUS.

the name of any Fire Insurance Office of good standing which effects insurances on risks as hazardous as tar distilleries -W. A. R.

Testing of Coal-Tar Products.-(Reply to T. C. W.)-The Royal Institution of Great Britain.-The following tional distillation, observing the proportions by volume passing op !

liquid products-naphthas, benzols, phenols, &c.-are tested by fracare the arrangements for the Lectures after Easter :- between certain temperatures, and in the case of phenol observing

Ernst Pauer.Three Lectures on Schubert, Mendels. also the proportion crystallising, and taking the melting point of this. sohn, and Schumann (with Musical Illustrations); on

These test-proportions, the temperatures at which they shall pass

over, and in the case of phenol the melting point, are us ially fixel Tuesdays, Aprill 22 16 May 6.

by the trade contract. I know no book containing an account of the e Professor Dewar, M.A., F.R.S.- Fives Lectures on methods, which are simple cases of fractional distillation. Informa. “ Dissociation;" on Thursdays, April 24 to May 29.

tion on the testing of anthracen and the other solid products, as also

of the aniline colours, &c., will be found usefully given in Bolley and H. H. Statham.-Four Ledures on the Leading Styles Kepp's “ Manuel Pratique d'Essais et de Recherches Chimiques of Architecture Historically and Æsthetically Considered; Appliqués aux Arts et à l'Industrie.” Paris: F. Savy, 24, kue on Saturdays, April 26 to May 17.

Hautefeuille.-WATSON SMITH, F.C.S., F.I.C.
Professor Kari Hillebrand.--Six Lectures on the In.
telle&ual Movement of Germany from the Middle of the
Last to the Middle of the Present Century; on Tuesday,

MEETINGS FOR THE WEEK.
May 13 ; Mondays, May 19, 26, June 2; Tuesday,
June 10; and Thursday, June 12.

MONDAY, 2181.-Medical, 8.30.

Society of Arts, 8. " Recent Advances in Tele. John Robert Seeley, M.A., Professor of Modern

graphy," by W. H. Preece. (Cantor Lectures.) History, Cambridge.- Four Lectures, on Tuesdays, May Tuesday, 22nd.— Civil Engineers, 8.

Royal Institution, 3. “ Schubert," by Mr. Ernst 20, 27, June 3; and on Thursday, June 5.

Pauer. Professor Henry Morley.--Three Lectures on Swift ; | WEDNESDAY, 23rd.–Society of Arts,, 8. "English Fresh-water on Saturdays, May 24 to June 7.

Fisheries," by J. Willis-Bund.

THURSDAY, 24th.-Royal, 8.30. The following are the probable arrangements for the

Royal Institution, 3. * Dissociation," by Prof. Friday evening Meetings after Easter, to which Members

Dewar. and their friends only are admitted.

Royal Society Club, 6.30.

is Generic Images," by Mr. Friday, April 25.- Francis Galton, M.A., F.R.S., M.R.I. Friday, 25th.—Royal Institution, 9.

Francis Galton, Generic Images.

Quekett, 8. Friday, May 2.—Professor John G. M'Kendrick, M.D. SATURDAY, 26th.—Royal Institution, 3. " Architecture," by Mr. H. H.

Statham. The Physiological Action of. Anæsthetics.

Physical, 3: “On Selective Reflection," by Capt, Friday, May 9.-Sir John Lubbock, Bart., M.P., F.R.S.,

Abney. “On some Phenomena Connected with M.R.I. The Habits of Ants.

Magneto-electric Induction," by C. Boys. Friday, May 16.-Professor A. Cornu. Etude Optique

"Notes from the Physical Laboratory of de l'Elasticité. (In French.)

University College, Bristol," by Dr. S. P.
Thompson

[ocr errors]

174

Composition and Quality of the Metropolitan Water.

April 18, 1879. COMPOSITION AND QUALITY OF THE METROPOLITAN WATER.

MARCH, 1879.

The following are the returns of the Society of Medical Officers of Health:

Ammonia.

Hardness on Clark's Scale.

Appearance in

2 foot Tube.

Organic.

Nitrogen as Ni

trates, &c.

Oxygen used to
Oxidise Organic

Matter.

Saline.

Total Solids.

Magnesia

Lime.

Chlorine

Sulphuric

hydride.

[blocks in formation]

Grs.

Grs.

Grs.

Grs. Grs. Grs.

Grs. Grs. Grs.

Degs. Degs Thames Water Companies. Grand Junction

Clear

0'000 0·008 0.165 0.062 21·20 8·020 0*720 1.152 2-360 1399 4:20 West Middlesex

Clear

0'000 0.007 0'120 0·064 21.00 8:170 0·576 1'080 2.160 154 3'70 Southwark and Vauxhall Clear

0'000 0'005 0'135 0'075 21'00' 7.840 0°721 1'152 1:400 14'4 3:30 Chelsea

Clear

0'000 0.008 0.126 0.064 19.80 7.280 0*720 1'152 1*740 14'3 3 30 Lambeth..

Clear

0 000 0.006 0·135 0'079 21'50 8120 0-721 1'152 14700 14:8 4:20 Other Companies. Kent..

Clear

0.000 0.002 0-360 0'004 29620 10-920 1081 1.800 2.730 17.6 510 New River

Clear

Ooooo oʻ004 Oʻ150 0'037 19:40 7.400 0.620 1'152 1670 14'3 3430 East London ..

Clear

O'000 o'ò08 0*126 0·064 23.80 8.840 0.940 1'290 2·100 16'5 4-20 The quantities of the several constituents are stated in grains per imperial gallon. Note.--The amount of oxygen required to oxidise the organic matter, nitrites, &c., is determined by a standard solu• tion of permanganate of potash acting for three hours.

C. Meymott Tidy, M.B.

THE

TO MANURE MANUFACTURERS. MONTHLY JOURNAL

OF SCIENCE BIOLOGY, ASTRONOMY, GEOLOGY, INDUSTRIAL ARTS equal to from 5 to to per cent ammonia.-Apply to David Shaw and

Woollen Shoddy; free from grease; containing nitrogen MANUFACTURES AND TECHNOLOGY.

Co., Clayton, near Manchester.

FOR SALE:--- About 150 tons Monthly of

AND ANNALS OF

Edited by WILLIAM CRookes F.R.S., &c.

The Advertiser, with considerable practical

experience as Sugar and Brewing Chemist, is wishing to meet a position where his knowledge would prove of service. High testimonials and references.-Address, M. N. T., CHEMICAL News Office, Boy Court, Ludgate Hill, London, E.C.

[blocks in formation]

The third number of the Monthly Series (April, 1879) is

Now Ready
Price One Shilling and Sixpence.

CONTENTS.
I. Is Nature Perfect ?
II. Thoughts on Our Conceptions of Physical Law. By Pro

Francis E. Nipher.
III. The Old Stannaries of the Wesi of England. By James

Quick.
IV. A New Theory of Terrestrial Magnetism. By Profs. Perry

and Ayrton.
V. The Jablochkoff Candle: Its Practical Results in London.

By Charles W. Quin.
VI. The Tornado at Wisconsin in 1878.
VII. The Electric Light for India,
VIII. Painless Death.
Correspondence-The Sea-Serpent-Spider's Web for Micrometers

-Adhémar's Theory of Evolution-The Senses

of the Lower Animals--Optical Illusions. Reviews of Scientific Works-Science Notes-Proceedings of

Scientific Societies.
London: 3, Horse-Stoe Court, Ludgate Hill.

[blocks in formation]

BY DR. MUTER.

DELL, a Grand, Romantic, Fairy, Musical Entertainment, Analytical Chemists will find this a concise and yet complete book

with new Scenes, Slides and Effects, conducted by Mr OSCAR of reference for the isolation and examination of the active principles

HARTWELL, at 4 and 9. TH: ELECTRIC LIGHT; GAS, what it of drugs. Special appendix on the microscopic characters of the

does and can do: THE STEAM ENGINE, &c., by Mr. J. L.

KING.THE ZULU WAR, by Mr. W. R. MAY,-vÚYnGES IN starches in food and drugs. opious index and qualitative courses

THE AIR, and THE WONDERS OF MODERN SCIENCE, by or resins, &c.

Mr. 7. Ć. HEPWORTH-THE 200CEPHALIC TROUPE of Pablished by W. Baxter at the Office of the South London School Living Marionettes.-STOKES on MEMORY.-LEOTARD the of Pharmacy, Kennington Cross, S.E., and sold by Messrs. Simpkin Automaton, and the AUTOMATIC HEAD.-Diver, Daving Bell, &c. and Marshall and Messrs. Baillière, Tindal, and Cox.

Admission, ie. Open at 12 and 2; Carriages at 5 and 10.

[ocr errors]

CHEMICAL
Preparation of Metals of the Platinum Series.

175

I now propose to give a short description of the methods THE CHEMICAL NEWS. I have employed for preparing the pure platinum and

iridium necessary for the manufacture of the alloy, which

I call “iridio-platinum," and it is upon the distinguishing VOL. XXXIX. No. 1013.

characteristics above-mentioned that my method of separation is chiefly founded.

Platinum. THE PREPARATION IN A STATE OF PURITY

The preparation of this metal to a state of purity is an OF THE GROUP OF METALS

operation of extreme delicacy. I commence by taking KNOWN AS THE PLATINUM SERIES, ordinary commercial platinum; I melt this with six times AND NOTES UPON

its weight of lead of ascertained purity, and, after granu. THE MANUFACTURE OF IRIDIO-PLATINUM.* tion of I volume to 8 of distilled water. The more readily

lation, dissolve slowly in nitric acid diluted in the proporBy GEORGE MATTHEY.

to ensure dissolution, it is well to place the granulated alloy in porcelain baskets such as are used in the manu.

facture of chlorine gas for holding the oxide of manganese. In this paper it is not my intention, nor should I be able, When the first charge of acid is sufficiently saturated, a to refer generally to the results of work in the various fresh quantity should be added until no more action is branches of platinum metallurgy carried out by my firm, apparent ; at this stage the greater part of the lead will who, as is well known, have been associated with the have been dissolved out together with a portion of any development of this special field of industry from its earliest infancy; but I shall confine myself simply to that copper, iron, palladium, or rhodium that may have been se&ion of it upon which my personal attention has of late present. These metals are subsequently extracted from years been specifically concentrated in order to meet and and the remaining metals by well-known methods.

the mother-liquors, the nitrate of lead by crystallisation, comply with the requisition of the Bureau Internationale des Poids et Mesures, the Sedion Françaises de la Com. state of an amorphous black powder (a form most suitable

The metallic residue now obtained will be found in the mission Internationale du Mètre, and of l'Association for further treatment), consisting of platinum, lead, and Géodésique Internationale (all of them important scientific small proportions of the other metals originally presentcommittees, formed with the object of arriving at an the iridium existing as a brilliant crystalline substance accurate and definite solution of the long agitated question insoluble in nitric acid. After digesting this compound of standard weights and measures), and also at the in weak aqua regia, an immediate dissolution takes place demand of the French Minister of War, for an alloy the of the platinum and lead, leaving the iridium still impure, best adapted for the manufa&ure of the international but effecting a complete separation of the platinum. metre and kilogram standard, and the geodesique rule ;

To the chloride of platinum and lead after evaporation and in my endeavour to solve this difficult problem I have is added sufficient sulphuric acid to effect the precipitahad the great advantage of being able to consult those tion of the whole of the lead as a sulphate, and the distinguished men, MM. Henri Sainte-Claire Deville and chloride of platinum after dissolution in distilled water is Henri Debray, of Paris, and have also had the benefit of treated with an excess of chloride of ammonium and the excellent and valued advice of M. Stas, the celebrated sodium, the excess being necessary in order that the preBelgian chemist, to all of whom the scientific world owe cipitated yellow double salt may remain in a saturated so much, and to whom I desire to offer my warmest thanks. solution of the precipitant. The whole is then heated In a paper of this kind it would be superfluous for me

to about 80', and allowed to stand for some days; the to enter into any of the already published details con- ammonio chloride of platinum will settle down as a firm cerning the existence and colle&tion of what is known as platinum-dust or mineral. It is sufficient for me to ob deposit at the bottom of the vessel, whilst if any rhodium,

as is generally the case, is present, the surface liquor serve that the six metals (of which platinum is the chier) will be coloured a rose tint, occasioned by a combination usually found more or less in association in their native of the salts of the two metals. state, present characteristics of interest beyond their

The precipitate must be repeatedly washed with a metallurgical utility, which are, perhaps, worth alluding saturated solution of chloride of ammonium and subseto en passant. It is, for instance, a curious fact that the quently with distilled water charged with pure hydrogroup should consist of three light and three heavy metals, chloric acid. This is necessary for its purification. The each division being of approximately the same specific small quantity of the double salt which will be taken up gravity-the heavier being (in round figures) just double and held in solution is of course recovered afterwards. the density of the lighter series. Thus we find osmium, iridium, platinum forming the Rhodium may still exist in the washed precipitate, which

must therefore not be reduced to the metallic state until first division, of the respective specific gravities of 22:43, its separation is completed, and this is best effected by 22:39, 21:46; whilst ruthenium, rhodium, and palladium mixing with the dried compound, salts of chloro-platinate are represented by the figures 11:40, 1:"36, 11, the average and chloro-rhodiate of ammonia, bisulphate oi po:ash with densities of the heavy and light divisions thus being a small proportion of busulphate of ammonia, and subrespectively 22-43 and 11'25.

jecting to a gradual heat brought by degrees up to a dull But a more interesting and important classification is red in a platinum capsule, over which is placed an in, what I may designate as a first and second class series, verted glass funnel. The platinum is thus slowly reduced from the more important view of their relative properties to a black spongy porous condition free from water, of stability. Thus platinum, palladium, and rhodium nitrogen, sulphate of ammonia, and hydrochloric acid, the form the first or higher class, not being volatilisable in a rhodium remaining in a soluble state as bisulphate of state of oxide ; iridium, osmium, and ruthenium forming rhodium and potash, which can be dissolved out com. the second or lower class, their oxides being more or less pletely by digesting in boiling distilled water ; a small readily volatilised. The oxide of iridium is effected at 700° to 800° C., and of sulphate, but is regained by heating the residue (ob

quantity of platinum will have been taken up in a state entirely decomposed at 1000°, whilst osmic and hypo- tained on evaporation) to redness, at which heat it is suthenic acids are volatilised at the low degree of 100°, reduced the metallic condition, the rhodium salt rethe latter exploding at 108°. The chlorides of these

maining undecomposed. metals can be sublimed at different temperatures (as also

By the method above described the platinum is freed the protochloride of platinum).

not only from rhodium, but from all other metals with * A Paper read before the Royal Society.

which it may have been contaminated, and is brought to

CHEMICAL NEWS, 176 Preparation of Metals of the Platinum Series.

April 25, 1879. a state of absolute purity, of the density 21:46, the highest charcoal crucible, is melted into an ingot, and after being degree obtainable.

broken up and boiled in hydrochloric acid, to remove any

possible trace of iron adhering to it through the abrasion Iridium.

in breaking up, should possess is perfectly pure a density In the preparation of this metal when intended to be of 22'39; but, as iridium prepared even with the utmost used for the manufa&ure of iridio-platinum alloy, I have care will still contain minute though almost inappreciable arrived at freeing it to the utmost possible extent from all traces of oxygen, ruthenium, rhodium, and possibly iron, its associate metals, except platinum, disregarding the the highest density I have yet attained is 22-38. presence of the latter; the proportion of which, once

Alloy of Iridio-Platinum. determined, would only form matter of calculation in the final operation of mixing my alloy.

This compound metal possesses physical properties of In practice, the purest iridium which can be obtained great value, forming a beautiful example of the effect of 2 from its ordinary solution (deprived of osmium by long careful combination of the opposite characteristics of its boiling in aqua regia and precipitated by chloride of am- component parts. Thus, the extreme softness and ex. monium) will almost invariably contain traces of platinum, pansiveness of pure platinum and the brittleness and rhodium, ruthenium, and iron.

excessive hardness of pure iridium, produce, by combinaI fuse such iridium in a fine state of division with tention in judicious proportions, a perfect and homogeneous times its weight of lead, keeping it in a molten state for alloy, possessing the necessary mean of these properties some hours, dissolve out the lead with nitric acid, subject to render it suitable for many important purposes, amongst the residue to a prolonged digestion in aqua regia, and others that of the special object to be attained to meet obtain a crystalline mass composed of iridium, rhodium, the requirements for an unalterable standard metal, for ruthenium, and iron, in a condition suitable for my further which it is peculiarly adapted. treatment. By fusion at a high temperature with an

In the manufacture of the prototype metres and the admixture of bisulphate of potash, the rhodium is almost geodesique rules (each 4 metres in length) ordered from entirely removed, any remaining trace being taken up my firm by the Comité Internationale des Poids et together with the iron in a later operation. The iridium Mesures, the Association Geodesique Internationale, and so far prepared is melted with ten times its weight of dry the French Minister of War, I proceeded in the following caustic potash, and three times its weight of nitre, in a

manner with the platinum and iridium prepared as gold pan or crucible; the process being prolonged for a described above. considerable time to effect the complete transformation of

Operating upon a charge of 450 ounces of platinum and the material into iridiate and ruthenate of potash, and the 55 ounces of iridium, I commenced by melting these oxidation of the iron ; when cold, the mixture is treated metals together and casting into an ingot of suitable with cold distilled water. The iridiate of potash of a shape, which I then cut into small pieces with hydraulic blue tinge will remain as a deposit almost insoluble in machinery. After re-melting and retaining in a molten water, more especially if slightly alkaline, and also the condition under a powerful blast of oxygen and common oxide of iron.

gas for a considerable time, I re-cast and forged at an This precipitate must be well washed with water charged intense white heat under a steam hammer, the highly with a little potash and hypochlorite of soda until the polished surfaces of which were cleaned and polished washings are no longer coloured, and then several times after each series of blows—when sufficiently reduced it with distilled water.

was passed through bright polished steel rollers, cut into The blue powder is then mixed with water strongly narrow strips, and again slowly melted in a properly charged with hypochlorite of soda, and allowed to remain shaped mould, in which it was allowed to cool.' I thus for a time cold, then warmed in a distilling vessel, and obtained a mass of suitable shape for forging, perfedly finally brought up to boiling-point until the distillate no

solid, homogeneous, free from fissures or air-holes, and longer colours red, weak alcohol acidulated with hydro- with a bright and clean surface at bottom and sides as at chloric acid.

top. At the first forging a bar was obtained 35 centims. The residue is again heated with nitre and potash water long, 7°5 wide, 2'5 thick, which weighedcharged with hypochlorite of soda and chlorine, until the In air

15*105 grms. last trace of ruthenium has disappeared.

In water at 70° F...

14'405 Further, to carry out the purification, the blue powder Showing a density at zero of 21522 (oxide of iridium) is re-dissolved in aqua regia, evaporated | A third of the bar was cut off and the larger portion again to dryness, re-dissolved in water, and filtered. The dark-coloured solution thus obtained is slowly 2.0, which weighed

forged to a length of 95 centims., width 2.5, thickness poured into a concentrated solution of soda and mixed

In air with hypochlorite of soda, and should remain as a clear

10814 grms. solution without any perceptible precipitate, and subjected

In water at 60° F...

10'315 in a distilling apparatus to a 'stream of chlorine gas,

Showing a density at zero of 21648 should not show a trace of ruthenium when hydrochloric This was then passed through highly polished rolls until acid and alcohol are introduced into the receiver. In this of a length of 4080 centims., 21 millims. in width, and operation the chlorine precipitates the greater part of the 5 millims. thick, to which a perfe&ly ređangular form was iridium in a state of blue oxide, which after being col. subsequently given by drawing it through a series of leaed, washed, and dried, is placed in a porcelain or glass plates, and thus prepared the rule was in a condition to tube, and subjected to the combined action of oxide of receive the beautiful polish of which this alloy is suscarbon and carbonic acid obtained by means of a mixture ceptible. of oxalic with sulphuric acid gently heated.

After passing it through each hole the metal was anThe oxide of iridium is reduced by the action of the gas nealed by means of a jet of gas and oxygen to a heat leaving the oxide of iron intact, the mass is then heated just below nielting point, and each time throughout after to redness with bisulphate of potash (which will take up forging, rolling, and drawing was exposed to the action of the iron and any remaining trace of rhodium), and after melted borax, and boiled in concentrated hydrochloric subjecting it to many washings with distilled water, the acid to remove any possible trace of adherent iron or residue is washed with chlorine water to remove any trace

other impurity. of gold, and finally with hydrofluoric acid, in order to take

A piece cut from the end and presented to the French out any silica which might have been accidentally intro- Academy of Sciences gave the following results :duced with the alkalies employed or have come off the Weight in air

116.898 grms. vessels used.

111469 The iridium, after calcination at a strong heat in a Showing a density of .. 210516

water

« PoprzedniaDalej »