MISCELLANY. 239 
merges in it a piece of platinum foil surrounded by a small zinc plate , 
when the copper is deposited on the platinum, colouring it red, and can 
be dissolved with a few drops of nitric acid. — Chem. Go z. from Jow . de 
Med. et de Chim. de Toulouse. 
On a new Acid in the Root of Robinia. By Hugo von Reinsch. — 
The author was induced, by the liquorice-like smell and taste of the 
acacia-root, to submit it to chemical examination ; in the course of 
which he discovered a peculiar acid, robinic acid, which occurs in the 
root in combination with ammonia. The presence of this salt is readily 
detected, even by exhausting with boiling water only 2 drms. of the 
root, evaporating the filtered solution to the consistence of a syrup, and 
setting it aside for some time. In the course of 12 hours, a tolerable 
quantity of hard rhombohedrons of robiniate of ammonia, with a vitre- 
ous lustre, will be found to have separated. This salt dissolves with- 
out colour in 20 — 30 parts water, is void of taste and smell, and has no 
action on litmus-paper. The hot concentrated solution is not altered by 
carbonate of soda ; with chloride of calcium, it yields a flocculent crys- 
talline, and with chloride of barium a pulverulent precipitate ; 
peracetate of iron produces a yellowish turbidness, nitrate of silver a 
slight opacity, protosulphate of iron a white precipitate, basic acetate of 
lead a white precipitate after some time, and protonitrate of mercury a 
floecnlpnt white precipitate. As the acid forms with lead a soluble 
compound, the author combined it with protoxide of mercury, and 
treated this with sulphuretted hydrogen^ In this way a colourless 
syrup was obtained, which on the addition of alcohol became converted 
into a mass of acicular crystals. From the smallness of the quantity, 
it could not be submitted to more accurate investigation. Besides the 
robiniate of ammonia, there also occurs in the root, sugar (no glycyr- 
rhizine,) fat and essential oil, chlorophylle, wax, tannic acid, a yellow- 
colouring principle, which becomes reddish brown by alkalies, mucil- 
age, much albumen, starch, salts, and an alkaloid, which the author 
has not yet succeeded in isolating. — Ibid, from Jahrb. fur Prakt. Phar. 
On the Preparation of Benzoic Acid. By Dr. L. Bley and E. Diesel. — 
The authors found, on comparing the various methods hitherto re- 
commended, that no one perfectly answered the purpose, and propose 
the following : — 8 parts of coarsely-powdered benzoin are heated to 
boiling with 3 — 4 parts hydrate of lime and 80 parts water, with constant 
stirring. The mass, pressed between linen, is boiled again twice with 
a little water, and again submitted to pressure. When the liquid has 
become sufficiently clear, it is filtered, and is evaporated down to one- 
fifth ; a slight excess of muriatic acid is then added to it, when the 
acid separates in beautiful crystals on cooling. It is purified by reso- 
