of carbon than those mentioned, is not
fully established.--_N.W. Shedd, M.I.T._
* * * * *
A NEW ABSORBENT FOR OXYGEN.
OTTO, BARON V.D. PFORDTEN.--The author makes use of a solution of
chromous chloride, which he prepares as follows:
He first heats chromic acid with concentrated hydrochloric acid, so
as to obtain a strong green solution of chromic chloride free from
chlorine. This is then reduced with zinc and hydrochloric acid. The blue
chromous chloride solution thus obtained is poured into a saturated
solution of sodium acetate in an atmosphere of carbonic acid. A
red precipitate of chromous acetate is formed, which is washed by
decantation in water containing carbonic acid. This salt is relatively
stable, and can be preserved for an indefinite time in a moist condition
in stoppered bottles filled with carbonic acid.
In this process the following precautions are to be observed:
Spongy flocks always separate from the zinc used in the reduction, which
float about in the acid liquid for a long time and give off minute gas
bubbles. If poured into the solution of sodium acetate, they would
contaminate the precipitate; and when dissolved in hydrochloric acid,
would occasion a slight escape of hydrogen.
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