a compound which remains in solution when diluted with 30 times its weight of water, whilst a solution of the bichloride of the same strength soon becomes troubled and precipitates. This non-precipitation of albumen will not only serve to distinguish the bibromide from the bichloride, but if bichloride of mercury is mixed with from th tooth of its weight of the bromide, it will detect the adulteration.-Jour. de Chim. Méd., April.

FLUORINE.

M. Baudrimont states that he succeeded in isolating fluorine two years since; but he did not announce this discovery because he could not obtain it without a large admixture of oxygen gas. The process by which he first obtained fluorine was by passing fluoride of boron over minium heated to redness, and receiving the gas in a dry vessel. His present method is to treat a mixture of fluoride of calcium and binoxide of manganese with sulphuric acid in a glass tube; but the gas thus obtained is mixed with the vapour of hydrofluoric acid and fluosilicic acid gas; this mixture however does not interfere with the observation of the principal properties of fluorine, which is a gas of a yellowish brown colour, and possesses an odour resembling chlorine and burnt sugar: indigo is bleached by it; it does not act upon glass, but combines directly with gold. L'Institut, 27th April, 1836. (See Messrs. Knox's paper in the present Number.)

ANTIMONIAL COPPER (ÉCLATANT).

Henry Rose analysed this mineral after separating the quartz with which it was mixed, and found its composition to be

which gives the formula Cu + S 6, analogous to the composition of zinkenite and miargyrite.-L'Institut, May 18, 1836.

ON THE ACTION OF BROMINE UPON ÆTHER.

M. Löwig added bromine to æther in successive small portions until it would not take up any more, and set the mixture aside for about a fortnight, when the æther was completely decomposed, giving rise to the following products, viz. :

1st, Formic acid.

2nd, Hydrobromic acid.

3rd, Hydrobromic æther.

4th, Dense bromic æther (schwerbromæther).
5th, Bromal

To separate these substances the decomposed liquor is to be distilled. The four first come over; and if the operation is not pushed too far, the bromal remains in the retort mixed with a little dense bromic æther and hydrobromic æther. By treating this residue with

water, and setting it aside for 24 hours, beautiful crystals of hydrate of bromal are obtained.

Bromal. Anhydrous bromal is composed of

8.64 4 eqs.

0.34 = 1 eq.

6.33 2 eqs.

84.65

3 eqs.

100.00

H1 O2 Br3

H1 04

The hydrate of bromal is formed of

1 eq.

1 eq. of bromal C 4 eqs. of water

of hydrate of bromal.. C4 H5 06 Br3

When the hydrate of bromal is boiled with an alkaline solution, eqs. C8 H10 O12 Br form

2 eqs. of formic acid C+ H2 05
2 eqs. of bromoforme = C He
6 eqs. of water

Bro

= H6 06

C8 H10 O12 Br6

Bromoforme decomposes into bromine and formic acid.

Dense Bromic Ether (schwerbromather). This is formed in great abundance in the decomposition of æther by bromine. It is very volatile, possesses a very penetrating and agreeable odour, and a sweet taste which remains for a length of time. It is much heavier than water, and even sinks in sulphuric acid. When it is boiled in this acid bromine is liberated, and a colourless fluid distils. Dense bromic æther can be obtained anhydrous by digesting it with caustic potash, and distilling it repeatedly from quick-lime. It is perfectly clear, as limpid as water, and refracts light very powerfully. When passed over red-hot lime it is decomposed, liberating a gas which burns with a clear flame, and forming bromide of calcium. When it is boiled with a solution of potash, bromoforme is evolved, which is decomposed into formic acid and bromine, forming formiate of potash and bromide of potassium. The composition of this ether deduced from three analyses, is

1st.

2nd.

3rd.

Carbon...
Hydrogen
Oxygen

....

Bromine.

Bromic æther being the heaviest of the fluids resulting from the decomposition of æther by bromine, it is very easy to separate it from the other products. It is still to be decided whether this is a separate compound, or a mixture of various substances.-Ann. de Chimie, March, 1836.

ON THE COMPOSITION OF THE CRYSTALLIZED HYDRATE OF POTASH.

M. Walter obtains hydrate of potash in fine crystals by pouring on three or four pounds of fused potash a little water, and when the mixture is cool, adding sufficient hot water to dissolve the remainder of the potash: at the expiration of 12 hours, by decanting the solution, the crystals will be found at the bottom of the vessel. The method of analysis adopted for determining the relative proportions of water and potash, was to neutralize a known weight of the crystals with hydrochloric acid, to evaporate the solution to dryness, and heat the resulting chloride of potassium to redness. 4-065 gram. of crystallized potash afforded 3-207 gram. of chloride = 1.684 gram. of potassium; and as 1.684 gram. of potassium = 2028 of potash (protoxide of potassium), the crystallized hydrate will be composed of

2-028 potash,

2.037 water,

4.065

which nearly agrees with the formula of 10 eqs. of water to 1 of potash.

The slight difference between the experimental and the calculated results is evidently owing to a little interposed water, and some slight degree of humidity which the surfaces of the crystals acquired during weighing.

There is also a third hydrate of potash, for 2-462 gram. of the crystals placed under the air-pump lost 0.527 gram., which indicates a compound of 21-4 water and 78.6 potash in 100 parts, or 1 eq. of potash.... 48 = 77.71 3 eqs. water... 27 = 22.29

75 = 100.00

Thus crystallized potash appears to lose 7 eqs. of water in vacuo.-Journ, de Pharm., June, 1836.

Note.-How this crystallized hydrate can be regarded as a compound of 1 eq. of potash and 10 of water I am at a loss to know, as the analysis approximates to 1 eq. of potash and 5 of water; but in any case the analysis does not indicate any atomic combination, for by it 48 of potash will combine with 48.3 of water, the equivalent of potash and water being respectively 48 and 49.-J. S. D.

ON THE COMBINATIONS OF CHROMIUM WITH FLUORINE AND CHLORINE.

Henry Rose has submitted the gaseous perfluoride of chromium

of Unverdorben to a rigid examination. He obtained the gas by acting on a mixture of fluoride of calcium and bichromate of potash by sulphuric acid; the gas when passed into water contained in a platinum vessel afforded a solution of the chromic and hydrofluoric acids, from which he obtained 2·16 of fluoride of calcium = 1·031 of fluorine, and 0.339 of chromium. A second analysis afforded 3.02 of fluoride of calcium, and 729 of oxide of chromium: the mean of these analyses is, chromium 25.57, and fluorine 74-43, in 100 parts. Although the mode of analysis adopted does not admit of absolute certainty, yet it affords an approximation to the true composition utterly at variance with the existence of a perfluoride of chromium, the composition of which, to be analogous to chromic acid, would be

Chromium..
Fluorine ..

33.4

66.6-100.0

whilst, according to M. Rose's analysis, the constitution of this substance approaches to a compound of 5, and not of 3 double eqs. of fluorine to 1 eq. of chromium, in which case it would be composed of

If this gaseous body is indeed a fluoride of chromium composed of 5 double eqs. of fluorine to 1 eq. of chromium, the existence of an analogous oxide of chromium containing 5 eqs, of oxygen and 1 eq. of chromium is not improbable.

The chlorochlomic acid of Thomson, prepared by heating a mixture of common salt, bichromate of potash, and sulphuric acid together, on analysis afforded from 1.241 gramme, 2.294 of chloride of silver, and 0629 of oxide of chromium, which indicate 45-6 of chlorine, 35.53 of chromium, and a loss of 18-87 in 100 parts. By a second analysis of this chloride prepared at another period, 3-33 of chloride of silver, and 0.975 of oxide of chromium were obtained from 1.802 parts, which results are equal to 45.59 of chlorine, and 37.95 of chromium per cent. ; and considering the deficiency as oxy. gen, this chloride according to the first analysis will be a compound of 2 eqs. of chromic acid and 1 eq. of chloride of chromium, which by calculation is equal to

Chromium
Chlorine..
Oxygen

35.38
44.51

20-11-100.0

This substance is the only known instance of a volatile combina tion containing chromic acid, and that, a volatile compound formed of an oxide and a chloride. M. Rose dissents from Thomson's opinion in regard to the composition of this body, considering it to be a compound of chromic acid and chloride of chromium, and not a combination of chromic acid and chlorine; for if we consider with Thomson that all the chromium exists as chromic acid, there will be, if we adopt M. Rose's analysis, an excess o 10 per cent., which he attributes to impurity of the carbonate of soda employed by Thomson in his analysis.

In endeavouring to prepare a compound of selenium analogous to

the compound of chromium by treating mixtures of the seleniates and chloride of sodium with sulphuric acid, chlorine and chloride of selenium analogous to selenious acid were obtained; and towards the end of the experiment green vapours rose, which condensed into an oily liquid composed of the selenious and sulphuric acids. Bromide and iodide of potassium mixed with bichromate of potash, and acted on by sulphuric acid, liberate respectively bromine and iodine in a state of purity without the slightest admixture of chromium.-Ann. de Chimie, January, 1836.

ON THE ACTION OF SULPHURIC ACID ON OILS.

M. Fremy in examining the kind of saponification which sulphuric acid exerts upon oil, has arrived at several facts in addition to those already ascertained by MM. Chevreul, Braconnot, and Caventou. The oils employed were olive and almond, and the results from both were perfectly similar. When olive oil is treated with half its weight of concentrated sulphuric acid, surrounding the vessel with a freezing mixture to prevent any elevation of temperature and consequent evolution of sulphurous acid, the acid being added very cautiously, after a few minutes the mixture becomes viscid, when the action is finished. Then the mass being treated with water, rather less than six times the bulk of the oil employed, the mixture separates into two strata; the superior is of syrupy consistence, whilst the lower is chiefly composed of water and sulphuric acid; this latter is a sulphoglycerate of lime (?), whilst the superior layer is a mixture of three acids, which he calls sulphostearic, sulphomargaric, and sulpholeic acids.

The aqueous solution of these acids decomposes in a few days, sulphuric acid being formed, and the three fatty acids precipitated. The sulphostearic and sulphomargaric acids possess little stability, as they always decompose in from 24 to 48 hours at most, which property M. Fremy has availed himself of to separate these two solid acids from the third, which is liquid, and is derived from the decomposition of sulpholeic acid. The two solid acids can be separated by means of alcohol; these he has named hydrostearic and metamargaric acids.

Hydrostearic acid is solid, white, insoluble in water, soluble in both alcohol and æther, from which it crystallizes in mammillated groups; it fuses at about 129° Fahr. Its composition is C35 H72 05: it loses an equivalent of water when in combination with bases. It may be volatilized without alteration. All its salts are insoluble in water, except the hydrostearates of soda and ammonia.

Metamargaric acid is white like the preceding; soluble in alcohol; fuses at 120° Fahr. Its composition is given in the formula C35 H70 O. It loses an equivalent (1?) of water in combining with bases, and becomes C35 H67 O3, that is, exactly the same composition as common margaric acid.

Hydroleic acid is a slightly coloured liquid at 32° Fahr.; is composed of C35 H66 O54; loses an equivalent of water by combination, and becomes C35 H65 O5. When distilled it is almost totally decomposed into carbonic acid, water, and an oil composed almost