parts its bulk of water; but M. Lesebour finds it more manageable
if diluted with forty times. In case pure distilled, or rain water
cannot be procured, a few drops of nitric acid--say six to the quart--
should be added to the common water.

Put into the bromine box a given quantity of this solution,
sufficient to well cover the bottom; the plate, having been
iodized to a deep yellow, is placed over it; the time
the plate should be exposed must be ascertained by making
a few trials; it averages from twelve to forty seconds.
When once ascertained, it is the same for any number of plates,
as the solution, which of course would become weaker and weaker,
is changed after every operation, the same quantity being
always put into the pot.

Chloride of Iodine.--This is prepared by introducing chlorine
gass into a glass vessel containing iodine; the iodine
is liquified, and the above named compound is the result.
Operators need not, however, be at the trouble and expense of
preparing it, as it can be obtained prefectly pure of Mr. Anthony,
205 Broadway, N. Y., as also all of the chemicals herein enumerated.
The compound is diluted with distilled water, and the plate submitted
to its action till it is of a rose color. Chloride of iodine alone,
is seldom if ever used now by American operators, as it does not
sufficiently come up to their locomotive principle of progression.
The next is also eschewed by the majority, although many of our
best artists use no other, on account of the very fine tone it
gives to pictures.

Bromide of Iodine.--This is a compound of bromine and chloride