The ferrotype and how to make it - The Grian Press

60
THE FERROTYPE.
secure that which is pure. Ether often, in fact
almost always, contains alcohol, and sometimes
water. Alcohol is sold as 95 per cent, which
will not test higher than 85.
The quantity of alcohol contained in a sample
of ether, may easily be ascertained by agitating
the ether in a graduated measure-glass, (a minim
glass does very well,) with half its bulk of a sat-
urated solution of chloride of calcium. This
should be poured in first, its height noticed, arid
the ether poured on its surface, the thumb then
placed on the top, and the two shaken together
when separated, the increase of bulk acquired by
the chloride of calcium indicates the quantity of
alcohol present, and for this, allowance should be
made in the addition of alcohol to the Collodion
afterward.
Water may be detected either in alcohol or
ether by allowing a drop to fall into spirits of
turpentine, with which they ought to mix with-
out turbidity—this is produced at once if they
contain water. For detecting water in alcohol,
benzole is a more delicate re-agent than spirits of
turpentine.
A perfectly pure solvent having been secured,
we shall proceed to consider the materials nec-
essary to excite or sensitize the Collodion, so that
the film, when introduced into the bath, may ex-
cite a chemical action with the nitrate of silver,
producing iodide of silver, which is deposited od
and in the substance of the Collodion film.
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