[English Edition, Vol. XVIII., No. 455, page 96; No. 456, page 108; No. 453, pages 71, 72; No. 454, page 84; No. 453, page 72; No.

Olinthus.-Nickel is produced in large quantities at Birmingham. The exact details of its manufacture are kept secret, but it is by a wet process in which the property of carbonate of lime to precipitate metallic oxides is made use of to purify the metal from iron, arsenic, and copper. By regulating the temperature and precipitating fractionally, it is possible to remove all these metals from the solution, leaving the nearly pure nickel behind.

Communications have been received from Hirst, Brooke and Hirst; J. R. Haas & Co.; F. W. Hartley; M. A. Baines (with enclosure); C. Heisch (with enclosure); E. Tanner; J. A. Brande; J. Syme (with enclosure); D. Dalrymple: Hinds Howell; J. Crompton; F. Ignacio Rickard; F. Foord; Dr. R. Angus Smith, F.R.S.; G. W. Eccles; D. Powell; H. McLeod; Ivan C. Michels (with enclosure); Townsend and Adams; F. A. Pooley; J. Ireland, Jun.; W. Little; Mitchell & Co.; A. L. Steavenson; J. Cliff; and H. Bassett (with enclosure); Messrs. Townsend and Adams; Louis Pokorny; S. Mellor; Prof. Heaton; J. T. Dafter; F. A. Aramayo; W. Leighton; E. Smith; G. Dutton; F. J. Harker (with enclosure); M. A. Baines; Mawson and Swan; Prentice and Co.; J. L. Denman; R. Wardrop; J. Parry; Rev. B. W. Gibsone; Street Bros.; J. Noble; J. Bowing; J. Spiller: Spottis woode and Co.; Dr. Röhrig; M. A. Whichelo; F. C. Calvert and Co.; Mottershead and Co.; J. Muspratt and Sons (with enclosure); E. Hunt (with enclosure); G. W. Eccles; E. Cetti and Co.; P. Squire; Dr. Horace Dobell (with enclosure); H. Yeates; E. Meldrum (with enclosure): J. Hardman; G. Pearson; Dr. T. Wood; D. T. Hughes, California (with enclosure); W. J. Wonfor; and Captain W. A. Ross, R.A. Books Received.-"Condensed Temperance Facts for Christians, with remarks on Ancient and Modern Wines and Malt Liquors." By J. Mackenzie, M.D. London: Trübner. "Britain's Drawbacks." By Rev. Professor Kirk. "Water, its Impurities and Purification." By the London and General Water Purifying Company. Development and present state of Dreher's Breweries." Vienna, 1868.

[English Edition, Vol. XVIII., No. 454, page 84; No. 455, page 96; No. 456, page 108; No. 453, page 72; No. 454, page 84; No. 455, page 96; No. 456, page 108; No. 453, page 72; No. 454, page 84; No. 455, page 96; No. 454, page 84.]

THE CHEMICAL NEWS. will mention only those which appear not to have been made before,

Vol. III. No. 5. American Reprint.

ON SULPHOCYANIDE OF AMMONIUM. *
BY DR. T. L. PHIPSON, F.C.S., &C.

Sulphocyanide of ammonium dissolves copiously in water and in alcohol, and these solutions offer considerable interest. In the first place, in dissolving rapidly in water this salt produces a greater degree of cold than any other compound with which I am acquainted.

This is a salt which can be obtained in large quanti-About half a litre of hot water being poured upon 500 ties from the products of the distillation of coal. It accompanies the other compounds of ammonia in the ammoniacal liquor of gas-works. In several works it is made to yield its ammonia for the production of sulphate of ammonia; for th's purpose it is distilled with lime after the carbonate and sulphide of ammonium have been distilled.

For many years I have noticed that the sulphate of ammonia supplied to commerce for agricultural and other purposes often contains a small quantity of sulphocyanide, say from 2 to 4 per cent, but latterly a much larger quantity, which increases its yield in nitrogen when submitted to analysis without bestowing upon the product a corresponding value in an agricultural sense. For though the nitrogen of the ammonium in the sulphocyanide can be utilised like that in sulphate of ammonia, that contained in the form of sulphocyanogen escapes. In other terms only one half of the nitrogen in sulphocyanide of ammonium is available in the manufacture of artificial manures, since the other half is partly volatilised as sulphocy anhydric acid, and partly decomposed by the heat of the reaction, which is sometimes great enough to ignite the bisulphide of carbon resulting from the decomposition.

grammes of the impure salt, I was surprised, on stirring the whole together, to find that hoar frost appeared immediately on the external surface of the vessel. The temperature of the solution was found to be between 2 and 3 degrees below zero, that of the hot water used 96°, showing that the temperature had sunk or 99° C., in the space of a few seconds.

98°

A substance which absorbs so much heat whilst dis

With

solving would be expected to give out again much caloric when it crystallises, and such is the case. saturated solutions the crystallisation is accompanied on this account with some curious phenomena. As solved again by the heat produced, giving rise to a one large crystal forms, the adjacent crystals are disseries of rapid movements in the liquid and along its surface. Some of these vibrations spread along the entire surface with the rapidity of lightning, and continue at short intervals until the whole liquid suddenly solidifies.

From concentrated solutions sulphocyanide of ammonium crystallises in large transparent plates of a slightly pearly aspect. These plates appear to be formed of long prismatic needles intimately united, and are best obtained with very concentrated solutions. When weaker solutions are caused to crystallise, right Within the last twelve months the quantity of sul-rectangular prisms are formed: they are often of great phocyanide of ammonium present in some kinds of length; I have occasionally obtained them 2 or 3 inches commercial sulphate of ammonia appears to have inlong. creased considerably, and several samples which I have examined recently have yielded upwards of 75 per cent of this salt; in fact, they were not sulphate of ammonia at all, but impure sulphocyanide of ammonium. I found it necessary some time ago to discover a means of estimating rapidly and with accuracy the amount of this product when mixed with sulphate and chloride of ammonium and the various organic matters which u accompany the commercial products.

su ar

Sulphocyanide of ammonium can be separated with tolerable accuracy from the sulphate by means of alcohol, in which it is freely soluble; but this method will not apply when chloride of ammonium is present also, nor does it give the sulphocyanide in a convenient form for weighing.

A method which I have satisfied myself gives very accurate results and is sufficiently rapid, consists in dissolving a given weight of the product in water, filtering, rendering the solution rather acid, and precipitating the sulphocyanogen as an insoluble salt of copper by the addition of equal equivalents of sulphate of protoxide of iron and sulphate of copper. The whole of the sulphocyanogen is eliminated in this manner. The copper compound is received upon a weighed filter, dried at 100 C., and weighed. It is anhydrous, and contains 2 equivalents of copper, 2 of carbon, 2 of sulphur, and I of nitrogen,-Cu,C.NS.

Having prepared a certain quantity of pure su'phocyanide of ammonium, I took the opportunity of studying some of its properties. Of these experiments I

* British Association, Norwich Meeting, Section B. VOL. III. No. 5.-Nov., 1868.

15

The alcoholic solution of sulphocyanide of ammonium presents in the highest degree the peculiar phenomena of supersaturation. A saturated hot solution after cooling will remain liquid for hours, probably for days together. But if the liquid is stirred with a glass rod it is immediately transformed into a mass of small crystalline plates. When, instead of a glass rod, a minute crystal of the salt itself is thrown into the supersaturated solution after it has become quite cold, at the same instant magnificent rectangular plates, having the four faces of the octahedron, begin to form rapidly upon the surface, and the vessel is soon filled with splendid crystals. The supernatant liquid separated from these can be made to deposit still a considerable quantity of small crystalline plates by being stirred rapidly for a minute or two with a glass rod.

A concentrated aqueous solution of sulphocyanide of ammonium has no action upon sulphur; but it dissolves a considerable quantity of iodine, and when the darkcoloured solution is diluted and heated, the yellow compound called sulphocyanogen" is precipitated, and the liquid becomes colourless. Bromine acts in a similar manner. Each drop of bromine on falling in o the warm solution produces a hissing noise; on boiling the liquid the sulphocyanogen compound is precipitated. These two precipitates are insoluble in alcohol and soluble in sulphuric acid like that which is produced by chlorine.

The action of chlorine gas upon solutions of sulphocyanide of ammonium is very remarkable. If the solution is dilute the sulphur is gradually oxidised to sulphurio acid, and no precipitate is formed. If concentrated, a dense precipitate of sulphocyanogen occurs after a lit

Nov., 1868

CHEMICAL NEWS

tle while. It is difficult to obtain the whole of the cyanogen in this form, even when the liquid is kept near its boiling point the whole time. When the decomposition is complete and the liquid separated from the precipitate is evaporated, it yields chloride of ammonium. The action of chlorine on this solution is yet incompletely known. The composition of the socalled "sulphocyanogen " has been much discussed. For some time this precipitate was considered to be the radical of sulphocyanhydric acid, but it was afterwards found to contain hydrogen and oxygen. The composition assigned to this substance by Laurent and Gerhardt, namely 3 equivalents of cyanogen, I of hydrogen, and 6 of sulphur, appears to be inadmissible. The results of my analysis of this compound correspond with those of Voelkel, not with those of Laurent aud Gerhardt. It should be stated, however, that Charles Gerhardt, to whom organic chemistry owes so many splendid investigations, whilst criticising Herr Voelkel's labours on sulphocyanogen, based his own opinion in this case upon an incomplete analysis of the substance in question. The product can be completely purified by washing with hot water and with alcohol should it contain any persulphocyanhydric acid, which seldom occurs, or when it does happen to be present is generally in too small a quantity to affect the results of the analysis. The dried precipitate is anhydrous. It has yielded

T. L. P.
20'00

Volkel.

19'93
1.08

Calculated.

19.83
0.82

0.78 .23.20

52.68

52:48

}

= C.H2N,S,O.

The insoluble copper salt above mentioned was suspended in boiling water, whilst a current of chlorine gas was passed through the solution, with the expectation of obtaining sulphocyanogen itself, but little or no decomposition ensued; when iodine was substituted for chlorine the copper compound was partially decomposed, with production of some iodide of copper and an odour of iodide of cyanogen.

In conclusion, I may add that as the products derived from sulphocyanide of ammonium are very numerous, it is not impossible that some of them may eventually be applied to some useful purpose; if so it will be satisfactory to know that we possess a supply of this salt as inexhaustible as that of coal itself.

NOTE ON THE

PREPARATION OF SOME ANHYDROUS SO-
DIUM DERIVATIVES OF THE SALICYLIC

SERIES.*

BY W. H. PERKIN, F.R.S.

of organic bodies by means of oxides, there is always an equivalent of water produced, unless the substance acted upon be an anhydride; therefore, if the resulting compound has any tendency to form hydrated products, such are nearly sure to be produced, and it often happens that it is difficult or impossible to remove this combined water. Having to prepare a quantity of hydride of sodium-salicyl (salicylate of sodium) in an anhydrous state, it appeared to me that if I could obtain it anhydrous at once that I should avoid that blackening and loss which this salt is subjected to unless dried very rapidly.

I first thought of dissolving sodium in the anhydride; but such a process is unmanageable, and could not yield a pure product.

It then appeared to me if I could work with absolute alcohol in place of water, that I might obtain this result, but then what was to be substituted for the metallic oxide? Sodium-alcohol was proposed, as it would yield only an equivalent of alcohol when decomposed, instead of an equivalent of water; with this product I succeeded perfectly.

To prepare the anhydrous hydride of sodium-salicyl, it is only necessary to dissolve a weighed quantity of sodium in about twenty or thirty times its weight of alcohol, and then to add the theoretical amount of hydride of salicyl, also mixed with alcohol. If these solutions are added hot the mixture will enter into ebullition, and beautiful golden scales of the new product crystallise out. After standing for about half an hour the new salt is filtered off, washed once or twice with alcohol, pressed between bibulous paper, and placed in the water oven, where it will be found to dry in a comparatively short time. Thus obtained the hydride of sodium-salicyl is of a beautiful primrose yellow colour. Sodium determinations of this product gave numbers showing it to be perfectly pure.

The reaction by which it is formed may be thus expressed :

On treating salicylic acid in a similar manner, using 2 equivalents of sodium to I equivalent of acid, a beautiful white salt, crystallising in needles is obtained. This, when dried and analysed, was found to be a di-sodium derivative-salicylic acid with both its acid and phenolic hydrogen replaced by sodium-it therefore corresponds to that series of salts obtained by Piria, and which led chemists to believe salicylic acid to be bibasic.

This salt is deliquescent and possesses a very alkaline reaction; it is very soluble in water. Its formation may be expressed thus:-

In the preparation of salts or other metallic derivatives the salicin dissolves, but after the lapse of a short time

British Association, Norwich Meeting, Section B.

a slightly crystalline powder forms and soon renders the

mixture quite pasty. On washing this product with alcohol and then drying it gently in the water-oven, it is obtained as a white, rather friable mass. Analysis of this body has shown it to consist of salicin with an equivalent of hydrogen replaced by sodium:

Although I have experimented with an excess of sodium alcohol, yet I have not been able to introduce a further quantity of sodium into salicin.

I have made similar experiments with gallic acid, but although the product always contained a very great deal more sodium than a normal gallate, yet I have not been able to obtain a definite product. This would appear to result from the insolubility of the salt in alcohol, as it is precipitated before the solutions can be well mixed, and is therefore not homogeneous in composition. It is possible that potassium alcohol would yield a better result.

ON THE ACTION OF NUCLEI IN INDUCING
CRYSTALLISATION.*

BY CHARLES TOMLINSON, F.R.S.

IN introducing this subject to the Chemical Section of the British Association, Mr. Tomlinson stated that it formed the subject of a note sent in to the Royal Society, as an addendum to his paper read before that body on the 28th May last, on Supersaturated Saline

Solutions." +

ring about fifteen hours, when the tube with its crystals was gently lowered into the solution. There was no action of the crystals as nuclei, and they were left in the solution for 48 hours without any change taking place.

A similar solution was put into clean test-tubes plugged with cotton wool. The tubes were placed in sulphuric acid and covered with a receiver, from which the air was pumped out. In about twenty minutes a crystalline crust formed on the surface of the liquid the solution to the bottom, but it did not act as a which, during the shaking of the air pump, fell through nucleus. On removing the tubes and taking out the cotton wool the solutions immediately became solid from the entrance of some mote or dust floating in the air, which being chemically unclean acted as a nucleus.

The reading of Mr. Tomlinson's paper excited a lively discussion, in which the President (Dr. Frankland), Professor Williamson, Dr. Gladstone, Mr. Crookes, and others took part. They all wished for a definition of a dirty surface in contradistinction to a chemically clean one, Professor Williamson calling to mind the old adage as to dirt being merely "something in the wrong place." Mr. Tomlinson remarked in reply, that the various effects explained by his theory would hereafter be referred to a general law of adhesion; that there were a large number of facts at present much obscured by theory which admitted of easy explanation on this principle of chemical purity; that the investigation was On that occasion it was noticed by one of the Fellows a long one and was now in progress; but to give some that some tubes, containing supersaturated solutions, exidea of what may be understood by a chemically unhibited by Mr. Tomlinson, had a saline crust just above clean surface and its mode of action, as compared with the liquid surface, arising from a portion of the water a chemically clean surface, dip a glass rod made chemiof the solution evaporating through the cotton wool cally clean into soda-water; there will be no separation with which the tubes were plugged. It was stated that of the gas, because the solution will adhere to it as a this saline crust did not act as a nucleus to the remain- whole; draw the glass rod through the hand slightly der of the solution, because, according to Mr. Tomlin-oiled or greasy, and then dip it into the soda water; it son's theory, it was chemically clean. The objection raised was, that in cases of ordinary crystallisation, as in nursing a crystal of alum for example, we must be dealing with chemically clean surfaces during the growth of the crystal. The answer to this objection is that in the case referred to none of the conditions of chemical purity are observed; the evaporating dish is not chemically clean, nor is the solution exposed to the air, nor is the air by which the crystal is suspended, nor is the crystal, for this is frequently taken out and exposed to the air, and abnormal growths are chipped off with the thumb-nail. If all the conditions of chemical purity could be ensured, it is probable that a crystal let down into a highly saturated solution of the same salt would not act as a nucleus to it. The solution would, according to this theory, adhere to it as a whole, and being saturated or supersaturated, would not dissolve it. To test this opinion, Mr. Tomlinson prepared, with very great care, a solution of the magnesia sulphate (two parts by weight of salt to one of water), which was filtered while boiling into a chemically clean flask in which the solution was again boiled, and while steam was issuing from the neck, a short wide tube attached to a wire, filled with crystals of the salt, all made chemically clean, was suspended in the neck, which was plugged with cotton wool at the same time that the lamp was removed. The whole was left du

British Association, Norwich Meeting, Section B.

+ See CHEMICAL NEWS, vol. xviii., p. 2. Am. Repr., Sept. 1868, page 114.

will be completely covered with gas, since there is an adhesion between a gaseous and an oily surface, while there is none between water and an oily surface. In like manner bodies that are exposed to the air contract an organic film from the condensation of the products of respiration and combustion, which film will adhere to the saline or gaseous particles of a solution, but not at all, or only imperfectly so, to the water of such solution. Hence there is a separation, and bodies are

said to be active as nuclei when they have been exposed to the air, when in fact they have only become

contaminated.

ON THE

CHEMICAL COMPOSITION OF THE GREAT
CANNON OF MUHAMMED II.,

RECENTLY PRESENTED BY THE SULTAN ABDUL AZIZ KHAN
*
TO THE BRITISH GOVERNMENT.

BY F. A. ABEL, F.R.S.

THIS interesting example of heavy ordnance of early date, which has recently been added to the Museum of Artillery at Woolwich, is one of the large bombards which have, for about four centuries, occupied positions in the batteries on the Dardanelles. There appear, as recently as 1829, to have been upwards of sixty of these great cannon, but at the present time only

* British Association, Norwich Meeting, Section B.