MISCELLANY. 
77 
powder, which i9 free from carbonic acid, yields on ignition 22 percent, 
water, which would correspond to the formula 3Fe 2 3 +8HO. On ig- 
nition the protocarbonate of iron leaves 59.48-60 per cent, anhydrous 
peroxide of iron Ibid, from Buchn. Repert. 
On the Preparation of pure Caustic Potash and Soda. By M. Bizio. — 
The best method of rendering potash and soda caustic is, according to the 
author, to mix a solution of 1 part of the dry carbonate salt with 1 part 
freshly-prepared dry hydrate of lime, and allowing it to stand in a closed 
vessel for 24 hours at a temperature of 68° to 78° Fahr., frequently sha- 
king it. The potash should be dissolved in 12 to 15, the soda salt in 
7 to 15 parts water ; the carbonate of lime separates in a granular state, 
and the clear caustic ley may be decanted. A weaker ley may be ob- 
tained from the residue by fresh treatment with water. — Ibid from Berze- 
Hus, Juhresbericht. 
Preparation of Pyrophorus from Alum. By M. Elsner. — An inti- 
mate mixture of 3 parts roasted alum and 1 of flour is conveyed into a 
phial, which is placed in a Hessian crucible rilled up to the neck with 
sand ; the crucible is then heated in a wind-furnace till the glass nearly 
melts. The phial is then stopped up and allowed to cool. A pyropho- 
rus made from 5 parts alurn and 1 part powdered charcoal, is also very 
good, and never fails if a sufficient heat has been employed in its pre- 
paration. — Ibid, from Journ.fur Prakt. CHem, 
On the Detection of Prussic Acid in Cases of Poisoning. By M. Wit- 
ting. — The method recommended by the author in suspected cases of 
poisoning by prussic acid, is to mix the mass with one-sixth alcohol, 
and to distil off one-fourth. If it contain prussic acid, the distilled pro- 
duct generally evolves the peculiar smell. To this product a little caus- 
tic potash is added, and then a mixed acid solution of protochloride and 
perchloride of iron, when prussian blue is formed. 
If it be suspected that the poisoning was effected with cyanide of 
potassium, cyanide of zinc, &c, some hydrochloric acid should be add- 
ed along with the alcohol previous to distillation. — Ibid, Berzelius's 
Jahresbericht, 
Employment of Castor oil seeds as a purgative. By Dr. Mialhe. — 
Castor oil according to M. Soubeiran is less purgative than the seeds 
which have furnished it. This is because the oil which flows from the 
press carries with it comparatively little of the resin which remains in 
the marc. 
M. Mialhe reports various therapeutic results obtained by the aid of 
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