of potassium. To clean small articles, dip each one into the solution and rinse

immediately in hot water; then dry and polish with a linen cloth. Larger articles are

cleaned by rubbing the surface with a small tuft of cotton saturated in the solution. As

cyanide of potassium is a deadly poison, care must be taken not to have it touch any sore

vessel and add a few pieces of zinc. Hot water is added and the silver boiled until clean.

It is best to use soft water. The tarnish is removed by the electrolytic action of the zinc

on the aluminum and the silver, and the latter will take on a bright luster. This method of

1) Beat to a foam the white of an egg, with the addition of a little ammonia. Add 9 oz.

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.

2) 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.

3) 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.

4) It is now ready for exposure. Expose under magnesium light and develop with a citrate oxalic developer, or

in the following hydroquinone developer:

Hydroquinone ………… 1 dr.

Bromide of potassium .... 6 dr.

Sulphite of soda .……….. 1-1/2 oz.

Carbonate of soda .……... 2-2/3 dr.

Water ………………….. 14 oz.