PREPARATION OF HYDROCYANIC ACID.

BY M. LIEBIG.

THE cyanide of potassium (prepared according to the method described in page 88 of our last number) is much better adapted than the ferro-cyanide for the preparation of hydrocyanic acid -a much larger product is obtained, and with greater facility in the distillation.

During the distillation of ferro-cyanide of potassium with diluted sulphuric acid, there is deposited, as is known, a blueish white powder, a combination of cyanogen, potassium, and iron, the composition of which is similar to that of the ferro-cyanide of zinc, and is expressed by the formula:

It will appear from the formation and composition of this body, that five atoms of ferro-cyanide of potassium, containing thirty atoms of cyanogen, will not afford more hydrocyanic acid than nine atoms of cyanide of potassium would, that is to say, only eighteen atoms, the other twelve atoms remaining in the blueish white ferruginous precipitate.

If the ferro-cyanide of potassium be transformed into cyanide (according to the process described in page 88 of our last number) twenty-five atoms of hydrocyanic acid may be obtained from five atoms of the ferro-cyanide, consequently seven atoms more than in the other way.

In effecting the decomposition of one atom of ferro-cyanide of potassium with sulphuric acid, it is generally directed to use a sufficient quantity of the latter to form with the alkali an acid sulphate of potash; in using the cyanide of potassium, there need only be added one atom of the hydrated sulphuric acid.

Equal parts of cyanide of potassium and hydrated sulphuric acid are the best proportions for preparing hydrocyanic acid; the sulphuric acid will form a neutral sulphate with the potash, and an acid sulphate with the ammonia resulting from the decomposition of the cyanate of potash. The cyanide of potassium should be dissolved in double its weight of water, and the sulphuric acid diluted with three times its weight of water, gradually added by small quantities at a time, allowing the effervescence which takes place to subside after each addition of the acid.-Annalen der Chemie und Pharmacie.

PREPARATION OF CYANATE OF POTASH.

BY M. LIEBIG.

THE cyanide of potassium (prepared according to the method described, page 88, in our last number) offers an excellent means for easily and economically procuring the cyanate of potash. In the preparation of this salt, the common litharge of commerce should be used, previously submitting it to a dull red heat.

Fuse a portion of cyanide of potassium in a Hessian crucible, and throw in a small quantity at a time of litharge reduced to powder, the oxide of lead is immediately reduced, and remains mixed in the form of a fine powder with the cyanate of potash, which is produced; but on increasing the heat, the metal fuses into a regulus. Decant the melted salt, and when cooled and powdered, boil it with alcohol until no more crystals are obtained on cooling the solution. The crystallization of the cyanate of potash from alcohol is not necessary in the preparation of urea.Annalen der Chemie und Pharmacie.

NEW METHOD OF PREPARING CHLORIDE OF ZINC.
BY M. RIGHINI.

Take of

Chloride of barium, pure and crystallized, 3xxss.
Sulphate of zinc, pure, 3xxvss.
Distilled water, 3xxxj.

Dissolve the sulphate of zinc in one-half the water, and the chloride of barium in the other half; mix the two solutions in a matrass, apply the heat of a water-bath for a few minutes only, to accelerate decomposition; filter, and evaporate the liquor over a water-bath, until reduced to about two ounces, put this on to a fresh filter, on which has been placed some animal charcoal with a few grains of powdered chloride of barium; evaporate the filtered liquor until the product left to itself presents the appearance of flakey crystals of a brilliant whiteness, which when dried, must be kept in a well-stopped bottle.-Journal de Chimie Médicale.

HYPOSULPHITE OF SODA.

BERZELIUS proposes the following as a simple and easy method of preparing the hyposulphite of soda, now extensively used in photography: Saturate a solution of carbonate of soda with sulphurous acid gas, so as to form a bisulphite of soda. Boil a weak solution of hydrate of soda with sulphur to saturation. Add the latter solution to the former until there shall be a slight excess of sulphuret of sodium; filter, evaporate, and crystallize. The salt thus obtained, when freed from the mother liquor, will be hyposulphite of soda.

DANGER OF ADMINISTERING SULPHATE OF POTASH,

AS A PURGATIVE, TO WOMEN AFTER CONFINEMENT,

BY M. CHEVALLIER.

THE author states, that pharmaceutists ought to exercise some precaution in supplying sulphate of potash, when ordered in doses of one, two, or four drachms, for women after confinement, unless prescribed by a medical man, as it seems capable, in some cases, of producing dangerous and even fatal effects.

A case is mentioned, in which a medical practitioner having administered two drachms of this salt to a female who had recently been confined, symptoms supervened which led to the supposition that the patient had been poisoned.

In another case, ten drachms of sulphate of potash were ordered to be taken in six doses. The patient died in two hours after taking the first dose. On analyzing the contents of the stomach after death, no other substance could be detected, to which the effect could be ascribed, besides the sulphate of potash.-Journal de Chimie Médicale.

CURCUMINE,

THE COLOURING MATTER OF TURMERIC.

BY M. VOGEL.

In this paper the author gives the following as the conclusions, to which he has arrived from the investigation of the subject:

1st. That curcumine may be obtained in a state of purity, by separating it from its combination with oxide of lead.

2d. That concentrated sulphuric, phosphoric, and hydrochloric acids, dissolve curcumine, and that it may be thrown down from these solutions in a flocculent precipitate by means of water.

3d. That nitric acid decomposes it, forming a yellow substance, somewhat resembling the resins.

4th. That it forms brown combinations with the alkalies, and may be separated by weak acids.

5th. That it assumes a much deeper colour with the salts of uranium, than with those of lead, or with the alkalies.

6th. That the soluble borates form grey combinations, more or less decided.

7th. That turmeric paper reddened with boracic acid, is not restored to yellow by acids, but assumes a blue tint when wetted with ammonia, and also more or less with the other alkalies.-Journal de Pharmacie.

ON HYDRATED PEROXIDE OF IRON,

AS AN ANTIDOTE FOR ARSENIOUS ACID.

BY WM. PROCTER, JUN.

THE American Journal of Pharmacy for April last, contains an interest. ing paper on the above subject, in which the author, Mr. Procter, jun. gives the result on his investigations, with the view of determining the relative power of the hydrated peroxide of iron, as an antidote for arsenious acid, in the recent state, and when kept for different periods of time. The following are the results to which he has arrived, and which will be seen to be somewhat at variance with the opinions which have hitherto been generally received. 1st. That hydrated peroxide of iron, even when kept under water, gradually decreases in its power of neutralizing arsenious acid.

2d. That if kept in the form of a thick magma, it will retain its properties longer than when mixed with much water.

3d. That this decrease in power is probably due to a change in the relative proportion of the oxide and the water chemically combined with it, as well as to an alteration in its state of aggregation.

4th. That from the experiments of Orfila and others, the dry hydrated oxide possesses the power to a considerable extent of neutralizing arsenious acid, and it should be used in the absence of the moist and recent preparation. 5th. That hydrated peroxide of iron may be obtained in a state fit for use in ten or fifteen minutes, by using a solution of the persulphate of iron; and, Lastly, That the recent oxide should be used in all cases where it is attainable, in preference to that long kept.

BOOKS RECEIVED.

Monographie du MADI CULTIVÉ ou MADIA SATIVA. Par VICTOR PASQUIER, &c. &c. pp. 133.

MADIA is a Chilian plant, which was introduced into Europe by M. Buch, gardener to the King of Wirtemberg. It belongs to the section Asteracea, of the natural order Composite, is an annual plant, and has been readily naturalized to a European climate. The root is fusiform; the stem cylindrical, hairy, branching at the summits, and furnished with sessile, three to five longitudinally-nerved leaves, which are semi-amplexicaul, opposite on the lower portion of the stem, and alternate on the upper; linear, lanceolate, entire, bright, hairy; and the higher ones excreting from the hairs a viscid fluid. The flowers are terminal and axillary, of a pale yellow colour, the disk florets tubular, the ray ligulate; the involucrum is globular, consisting of scaly, unequal, lax, lanceolate, acute, velvety, viscid leaflets, disposed in two ranks. The fruit, like that of the order to which the plant belongs, is an achenium, smooth, angular, convex on one side, flat on the other; and devoid of pappus.

The whole plant is viscid, and exhales a powerful odour, which is somewhat like heated honey. It flowers in July and August. It requires rather a rich soil, of a ferruginous cha

racter.

M. Pasquier has entered minutely into the mode of preparing the soil for receiving the seed, directions for sowing it, and for weeding, transplanting, and harvesting the produce, as well as the mode of drying the plant, and separating the seed. He next proceeds to examine the constitution of the seed, 100 parts of which consist of 26.5 of testa, and 73.5 of kernel; 100 parts of the latter of which yields 31.3 of vegetable albumen, gum, and lignine, 56 of fixed oil, and 12.5 of water. In dry seasons, the oil is both more abundant and better than in damp seasons. The produce of oil compared with that of the poppy, is equal; with colza, as 32 to 28; with linseed, 32 to 21; with the olive, 32 to 16. The leaves and stems of the plant are rejected

by cattle; but the oil-cake, which always retains a considerable portion of the oil, forms a nutritive food for cattle, who are fond of it.

The oil of Madia, expressed without heat, is transparent, of a golden yellow colour, inodorous, rather fatter than the oil of rape or olives, and of a soft, agreeable, nutty taste; and is fit to be employed in the preparation of food, in salads, and for all the purposes of the best and mildest fixed oils. It burns with a brilliant reddish-white flame, and leaves no residue. It is little liable to become rancid, and is completely decolorized by animal charcoal. It dissolves sulphur, phosphorus, and wax; and is soluble in ether, but insoluble in alcohol. M. Pasquier, also details the action of the acids, the alkalies, and the metallic oxides upon this oil, in which it is unnecessary to follow him. On DISEASES of the BLADDER and PROSTATE GLAND. By WILLIAM COULSON. Longman, Brown, Green, and Co. An Essay on DIABETES. By H. BELL, D.M.P. Translated by ALFRED MARKWICK. Highley, Fleet Street. ALTHOUGH these works are designed for the Medical Practitioner more than the Pharmaceutical Chemist, yet they contain matter that would be read with interest by many of our members. The Chemist is sometimes applied to, in the treatment of diabetes, for the determination of the amount of sugar contained in the urine; and he may often in other ways assist the medical attendant by ascertaining the nature of the chemical changes which take place in the secretion. Mr. Coulson, indeed, in his interesting and valuable book, has availed himself of the investigations of one of our members in the chemical department of his subject.

"For the following observations," he says, "on sulphur, phosphorus, chlorine, lime, and magnesia, I am indebted to my friend Mr. John T. Barry, one of the best practical chemists of our time.

"Sulphur.-No fact in chemistry is better established than the existence of sulphur in the blood: nor is its existence less certain in urine. There is, however, this remarkable difference between the two :-In the blood very little is in the state of sulphuric acid; while in the fluid derived from that same blood and passed by the kidneys, the greater part of the sulphur is found to be oxidated to its maximum-that is, converted into sulphuric acid, and neutralized. The question then arises, Whence is the requisite oxygen supplied?"

We have already devoted so much space to the subject of Animal Chemistry, in this number, that we must refrain from quoting the further details of Mr. Barry's investigations, and refer the reader to Mr. Coulson's work, in which they are described.

Berzelius says, that none at all was found in his experiments; probably with ox blood. I found a distinct trace of sulphuric acid in human serum, though insignificant in quantity as compared with what exists in the urine.-J. T. B.