Isomorphism of Ammonias.

A few experiments made in this direction gave the following results :

Ethylamine alum.-Octahedra of sulphate of ethylamine and alumina were obtained.

Tartrate of diethylamine and soda.-In order to determine whether diethylamine was capable of replacing ammonia in the magnificent crystalline forms of the double tartrates, this salt was formed, but whether crystallised from water or from weak alcohol, only needles could be obtained.

Sulphate of diethylamine and zinc.-In order to determine if diethylamine was capable of replacing ammonia in Mitscherlich's group of double sulphates, RO,SO2+ MO SO3+6HO, with the characteristic crystal form, the double sulphate of zinc and diethylamine was formed. A deliquescent solution was obtained, which, in vacuo over sulphuric acid, afforded a crystalline mass, from which no conclusion as to isomorphism could be drawn. -American Journal of Science.

On Perchromic Acid, and the Action of Peroxide of Hydrogen on the Higher Oxides, by M. H. ASCHOFF. Ir is known that when dilute solutions of bichromate of potash and peroxide of hydrogen, containing a certain amount of acid, are mixed together, a blue liquid is obtained which becomes decolorised more or less rapidly with disengagement of oxygen (Barreswil). When there is sufficient peroxide of hydrogen there finally remains only a chromic salt, the oxy-water and the chromic acid having both lost part of their oxygen.

M. Aschoff having endeavoured to ascertain the quantity of oxygen disengaged in this reaction, found that for one atom of bichromate of potash employed there were always collected more than six atoms of

1 Jahresbericht der Chemie, 1858, p. 340.

129

oxygen; but that this relation was not constant. M. Wöhler found that one molecule of peroxide of manganese decomposed exactly one molecule of oxy-water. According to this fact, and also to the opinions of M. Schönbein, it ought to be supposed that one atom of bichromate of potash should decompose three molecules of oxy-water, setting at liberty six atoms of oxygen. It will be seen that this is not the case.

M. Aschoff first satisfied himself that the decomposition of oxy-water by permanganic acid took place between one molecule of the acid and five molecules of peroxide of hydrogen. He commenced by estimating the peroxide of hydrogen in a dilute solution by means of a standard solution of ammoniacal sulphate of protoxide of iron, and a similarly standardised solution of permanganate of potash: the estimation was made very readily. On directly treating oxy-water with permanganate of potash, he found that the same volume of solution of permanganate is necessary to decompose the oxy-water, and to peroxidise the amount of ammoniacal sulphate of iron, which on its part can remove from the same volume of peroxide of hydrogen its second atom of readily decomposes five molecules of oxy-water, and oxygen. One molecule of permanganic acid therefore may thus be used advantageously for the estimation of peroxide of hydrogen. When the solution of oxy-water takes place immediately, and the manganese passes to is very acid, the reduction of the permanganic acid the state of a salt of the protoxide. When, on the contrary, there is only a small quantity of the free acid in the liquid, as, for instance, when the oxy-water is poured drop by drop into the neutral permanganate of potash, there separates at first a manganese compound which is probably the hydrated peroxide; but upon the addition of a larger quantity of oxy-water, this hydrate re-dissolves, and the final result is the same as before; that is to say, that ultimately for one atom of oxygen which the permanganic acid gives up, the oxy-water likewise disengages one atom of oxygen, or one molecule of permanganic acid decomposes five molecules of oxy-water, becoming reduced to the state of manganous acid.

Having at his disposal a means of standardizing solutions of oxy-water, the author caused hydrated peroxide of manganese and peroxide of lead to react upon an excess of oxy-water. On estimating the undecomposed peroxide of hydrogen, he found that these bodies act upon oxy-water atom for atom.

On working in a similar manner with bichromate of potash, he, as in his first experiments, obtained variable results, according to which from 3°2 to 42 molecules of oxy-water are decomposed by one molecule of bichromate of potash; this may be explained by admitting with M. Barreswil, that perchromic acid is formed at first, but that at the same time a portion of the chromic acid is immediately reduced by the oxy-water before being peroxidised by it.

M. Aschoff has found a still more conclusive proof of the existence of perchromic acid. M. Barreswil had observed that on carefully mixing very dilute solutions of bichromate of potash and peroxide of hydrogen, the disengagement of oxygen docs not take place immcdiately; that the ether perfectly removes from the water the combination which communicates to it the blue colour; that the ethercal solution, much more stable than the aqueous solution, leaves, when evaporated at a low temperature, chromic acid without a trace of oxide; and

1 Annala de Chemie und Pharmacie, xci. 128. 2 Repertoire de Chimie pure, i. 205.

On shaking a known volume of the blue ethereal solution with an acid standard solution of a ferrous salt, there is an immediate decoloration, and the liquid then only contains oxide of chromium, peroxide of iron, and an excess of protoxide of iron, which can be estimated in the usual way. If the blue liquid is previously treated with potash, and then mixed with ferrous sulphate, it is found that the amount of protoxide of iron changed into peroxide is not the same as in the preceding experiment, and that the quantities of oxygen yielded are in the proportion of 4 to 3, as would be the case on the supposition that the blue liquid contains perchromic acid, and that the effect of the potash is to change this acid into chromic acid.—Journal für Praktische Chemie, lxxxi. 401.

a crystalline base formed by the condensation of three molecules of aniline, reunited by carbon substituted for hydrogen.

The production of this body is accompanied by that of a magnificent crimson colouring matter.

It may, perhaps, be useful to reproduce the passage which treats of the colouring matter:

"On submitting a mixture of bichloride of carbon and three parts of aniline, both in the anhydrous state, for nearly thirty hours, to a temperature of 170° to 180°, the liquid becomes transformed into a black mass, either soft and viscid, or hard and brittle, according to the length of time and the temperature.

"This black mass adhering persistently to the tubes in which the reaction takes place, is a mixture of several bodies. On exhausting with water a portion is dissolved, another remaining insoluble in the form of a more or less solid resin.

"The aqueous solution yields with potash an oily precipitate, containing a considerable proportion of unchanged aniline. On boiling this precipitate in a retort with dilute potash, the aniline distils over, whilst there remains a viscid oil gradually solidifying with a crystalline structure. Washing with cold alcohol and one or two crystallisations from boiling alcohol, render the body perfectly white and pure, a very soluble substance of a magnificent crimson remaining in solution.

"That portion of the black mass which remained insoluble in water, dissolves very easily in hydrochloric acid; it is again precipitated from this solution by alkalies in the form of a amorphous powder of a dingy red colour, soluble in alcohol, which it colours a rich crimson. The greater portion of this substance is the same colouring matter which accompanies the crystalline body."

The action of tetra-chloride of carbon on aniline only furnishes a comparatively small quantity of the red matter; moreover, the temperature to which the mixture is exposed, and the relative proportions of the wo substances which react on one another, are not

Carbo-triphenyl-triamine and the base, which takes a crimson tint on dissolving in alcohol, are not the only products of the reaction. Other bases are formed, for the most part amorphous, and accessible only in the form of platinum salts, which on account of the similarity of their chemical characters hinder the purification of the new compound. In spite of many attempts, I could not succeed in obtaining the colouring matter in a fit state for analysis, and I temporarily abandoned the investigation.

However, commerce has not failed to discover new and more advantageous methods for the production of aniline red. Certain metallic chlorides (tetra chloride of tin) and nitrates (mercurous nitrate) as well as a large number of oxidising agents, are capable of converting aniline into this crimson body. M. Verguin was the first to prepare the colour on the large scale by the action of tetra-chloride of tin on aniline. Since that time the production of aniline red has become an important branch of manufacture, which, in the hands of MM. Renard Brothers, in France, and Messrs. Simpson, Maule, and Nicholson, in England, has rapidly attained colossal proportions. The interest attached to this subject is evident on glancing at contemporary periodicals. The journals of applied chemistry especially furnish numerous descriptions and processes for the formation of the colouring matter which it has been proposed to call Fuchsine, Magenta, or other fantastic terms. The action even of tetra-chloride of carbon on aniline, which, at first sight, does not appear to possess ány importance, has been utilised on the large scale, and interesting observations on the commercial production of the colour by means of chloride of carbon have been published by M. Charles Dolfus Galline, by MM. Monnet and Dury, and finally by M. Louth3, and have proved that aniline red thus prepared on a large scale can be applied to dyeing, and furnishes exactly the same results as the colouring matter produced by other methods. This is not the place to give the details of the development of this new branch of industry, which has, moreover, been admirably traced by M. E. Kopp in a series of interesting articles. I have, however, thought it proper to quote the above authorities, so as to show that the basic colouring matter which I observed in 1858, when studying the action of tetra-chloride of carbon on aniline, is identical with the aniline red now manufactured by several processes on so large a scale.

A substance possessing such remarkable properties as aniline red, and which can also be procured as a commercial product, merits the attention of men of science.

The subject has been successively examined by M. Guignet, M. Béchamps, M. Wilm, MM. Persoz, De Luynes, and Salvétat, M. Schneiders, and more recently by M. Emile Kopp and by M. Bolley10. The results obtained by these experiments are far from being concordant. I attribute this divergence of the results on the part of such skilful observers, to the obstacles which they met with in procuring the colouring matter in the 1 Repertoire de Chimie Appliquée, 1861, p. 11. 2 Ibid, p. 12.

3 Ibid.

置

oil to a thin homogeneous fluid of iodine colour, with scarcely any precipitate.

Ether sol. bromine shows little reaction; a circular yellowish brown colour is produced; the supernatant liquid nearly colourless and perfectly transparent, afterwards light brown and cloudy.

Oleum Carui.-Yellow, old, thick, oily. Iodine.-There was some reaction, but no perceptible heat and no vapours; the residue was a yellowish brown liquid and a dark brown extractive mass, which were readily miscible. Odour balsamic, acidulous.

Ether sol. iodine.-Some irregular motion towards the circumference; the homogeneous thick liquid has a concentrated iodine colour, a small quantity of a lighter liquid separates, which afterwards re-unites to a uniform thick balsamic mass.

Bromine produces a hissing noise on coming in contact with the oil, and evolves some gray vapours; the mixture consists now of a deep reddish brown sediment and a light yellow coloured oil, which are readily miscible to a yellow oil with but a faintly brown tint.

Odour little modified.

Ether sol, bromine appears not to readily mix at first, but is for some time retained in a semicircle of yellowish brown, afterwards red brown; the supernatant oil is light brown and slightly turbid.

Oleum Caryophylli.-Fresh specimen, pale, yellowish

brown.

Iodine dissolved slowly and quietly to a greenish yellow brown mass of honey consistence and unaltered odour; the India oil dissolves it still slower to a clear, viscid, yellowish red liquid. Z.

Slow solution, at first yellow, afterwards reddish, thick odour unaltered.

Ether sol. iodine mixes uniformly to a yellowish red, iodine coloured liquid.

Ether sol. bromine.-The yellow colour of the mixture quickly disappears, by changing to greenish, greyish green; an aqueous liquid (from the ether) collects on the surface and is nearly colourless; the oily heavy stratum alters its colour to a pale greyish black, then brownish

black.

Oleum Cinnamomi Chinensis.-Fresh specimen,
brownish yellow.

Iodine dissolves quickly in the oil of Ceylon cinnamon, with little radiating motion and much heat, to a tenacious, greenish yellow brown mass of cinnamon odour. In the oil of Chinese cinnamon, iodine dissolves slowly without any visible motion or reaction, and, with little heat, to a yellowish red brown mass of the consistence of soft extracts, and of cinnamon odour. Z.

It dissolves quietly to an iodine coloured liquid; it then turns yellowish brown, blackish brown, and thickens considerably.

Ether sol. iodine.-No spreading; the colour changes from iodine to a peculiar yellowish brown black; the liquid is of a uniform thick consistence and in thin layers transparent; in six hours it is of a darker colour

and the consistence of a soft extract.

Ether sol. bromine mixes readily to a lemon yellow liquid, which gradually turns brown to umber brown, and is less thick than the product of the reaction of iodine.

Oleum Chenopodii Sem.-Thin, reddish yellow,
Baltimore oil.

Iodine. Rather slow reaction, without the evolution cf vapours; the residue consists of a yellowish brown

liquid and a dark brown resinous iodine compound, readily miscible to a brown or yellowish brown oil.

Ether sol. iodine causes a slight effervescence and forms two strata, the upper one of which is yellow, the lower one of a thick iodine colour; afterwards spreading takes place, and in a few hours nothing has been left in the vessel.

Bromine.-Hissing fulmination, with red and white vapours; the residue is a reddish brown resinous mass, and a light brown liquid, which after a while are miscible to a deep yellowish brown oil. Odour altered, somewhat

resinous.

Ether sol. bromine.-The reaction proceeds slowly ; the heavier liquid is reddish, tinged with brown; the supernatant fluid is light brown, almost clear.

Oleum Erigeronis.

The commercial article of this oil, which has a yellowish brown colour, and has been recommended by eclectic practitioners, was used for the following experiments. As Mr. F. L. John, of Philadelphia, obtained but an exceedingly small quantity from Erigeron Philadelphicum, the examined oil must be gained from Erigeron Canadense; but I have no means of ascertaining its purity.

Iodine dissolves with radiating motion, but without explosion; the solution is iodine-coloured, and has a thick blackish sediment.

Ether sol. iodine mixes to a solution and sediment of the same properties.

Ether sol. bromine is miscible, then separates to a brownish green yellow thin liquid, a brownish black sediment, and a few violet-coloured spots.

Oleum Faniculi-Almost colourless, agreeable and pure fennel odour.

Iodine.-Oils, rich in stearopten, show radiating motion, evolve some reddish vapours, and thicken to a syrupy or soft extractive mass; oils with much stearopten, produce almost instantly a solid brittle mass, which prevents the further reaction of iodine. Iodine seems, therefore, applicable as a test for the proportion of stearopten in oil or fennel; but stearopten altered by age does not congeal to such a brittle mass, and the specific gravity must then decide whether the oil is in its fresh state, or old and resinified. Z.

Iodine dissolves with radiating motion, and some vapours, to a yellow, afterwards red liquid; the dark sediment is with some difficulty miscible, and forms an extractive mass.

Ether sol. iodine mixes uniformly to a bright red iodine-coloured solution, which, on standing six hours, is reddish brown, viscid.

Ether sol. bromine produces a mixture which is at first white and milky, and gradually shows some brown streaks; afterwards the supernatant fluid is milk white, tinged with greenish brown; the sediment has a purely brown colour.

Oleum Gaultheria.-Brownish yellow, thin, oily. Iodine dissolves quickly and completely with brisk reaction and some white vapours; the liquid is not thickened, and has a yellow iodine colour.

Ether sol. iodine. Some spreading; miscible to a yellowish red solution; after six hours the thin liquid is of a deep reddish yellow, without a trace of sediment.

Ether sol. bromine.-Many white fumes are given off, reminding somewhat of the odour of fresh parsley-root; the whole watch crystal is covered with a coating of a soft, resinous white substance, leaving some unaltered oil behind.

(To be continued.)