and 3 dr. of water and beat again. After the
egg has settled, filter and let the liquid run over the dial,
which has been previously cleaned with ammonia. When the surplus
has run off, coat with the mixture and allow to dry.
A sensitive collodion is now produced as follows: Dissolve 9 gr.
of chloride of zinc in 5 dr. of alcohol; add 7-1/2 gr. of
collodion cotton and 6-1/2 dr. of ether. Shake the whole forcibly.
Dissolve 23 gr. of nitrate of silver in hot water, add 1-1/2 dr.
of alcohol and keep the whole solution by heating. The silver
solution is now added in small quantities at a time to the
collodion, which must be well settled. This, of course, is done in
the dark room. After 24 hours the emulsion is filtered by passing
it through cotton moistened with alcohol. This durable collodion
emulsion is now flowed thinly upon the prepared watch dial, which,
after the collodion has coagulated, is moved up and down in
distilled
water until the fatty stripes disappear. The water is then
changed once, and after a short immersion, the dial is left to
dry on a piece of blotting paper. It is now ready for exposure.
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