SCIENTIFIC SUMMARY. 
495 
gas being allowed to escape, produces nitrous acid, which acts as a powerful 
disinfectant. It is suggested that a small instrument upon this principle 
might be constructed for domestic use, on the same plan as a Dobereiner’s 
lamp. — Chemical News , Aug. 31st. 
A Compound of Oxide of Cadmium and Potash. — M. Stanislaus Meunier 
has described a curious compound of this kind to the French Academy. 
Some time ago he stated that oxide of cadmium dissolves readily by fusion 
in potash or soda, a definite cadmiate of potash being formed. He gives the 
following account of the process : — Fused potash is saturated with oxide of 
cadmium, and while the mixture is kept in a state of fusion a cold solution 
of potash is carefully added. After each addition of the solution a white 
precipitate forms, which redissolves ; but after a time this precipitate becomes 
permanent. When this happens the author stops the process, and allows the 
mixture to cool slowly. It thus becomes a crystalline mass, but at the 
bottom some of the white precipitate is found. The crystals do not entirely 
dissolve in water. The liquid is seen to be full of pearly shining scales, 
which, when collected, are found to be quite insoluble in water, and to be 
rich in oxide of cadmium. They are, in fact, according to the author, 
hydrated cadmiate of potash, but he has not yet obtained them in sufficient 
quantity to analyze. The compound is hydrated, he says, for a prolonged 
boiling with a solution of potash decomposes it, and causes a deposition of 
oxide of cadmium ; it contains cadmic oxide combined with potash, for acids 
cause the disappearance of the scales, and produce amorphous hydrate of 
oxide of cadmium soluble in an excess of the acid. — Vide Comptes Bendus , 
Aug. 20th. 
Peroxide of Hydrogen. — Schoenbein has been pursuing his investigations 
upon this compound. He states that a solution of peroxide of hydrogen 
may be concentrated by boiling, and almost completely dehydrated by eva- 
poration over sulphuric acid and under an air-pump, at the ordinary tem- 
perature. The peroxide, though less volatile than water, yet possesses a 
distinct degree of volatility, as M. Schoenbein’s experiments demonstrate. 
Filter paper saturated with solution of H 0 2 , and dried at the ordinary tempera- 
ture, will give all the reactions of the peroxide. Such a strip of paper touched 
with acetate of lead is rapidly coloured brownish-yellow ; touched with a 
mixed solution of ferrid-cyanide of potassium and a persalt of iron it becomes 
blue ; with a diluted mixture of sulphate of iron and of iodide of potassium 
with starch, a deep blue colour is produced ; a solution of chromic acid con- 
taining sulphuric acid also gives a blue colour. M. Schoenbein has fomid 
that when a piece of this prepared paper is placed in a bottle of ozone, it 
ceases to give the reactions of peroxide of hydrogen ; for the peroxide is 
converted by the ozone into water. He records several other reactions, all 
of which show that for purposes of testing, the paper is equally valuable as 
the solution of peroxide. — Vide Journal f Hr Praktische Chemie. 
Composition of Oil of Samphire. — The common plant so much used in 
certain parts of England as a pickle has been analyzed by M. Herouard, who 
has given the following minute account of the properties of the volatile and 
fixed oils which this umbelliferous plant contains : — The oil of samphire is 
composed of a light and a heavy oil, the latter separating from the milky 
distilled water on standing, the former, which is the aromatic oil of the 
