If you were to augment the proportions of the ammonia or chloride of gold, the operation would progress much quicker, but then the middle of the proof would be always much clearer than towards the border.

The mixture may be used several times without being renewed.

It does not, however, give such a beautiful color to the impression as when it is newly prepared.

By communicating to the vessel containing the solution a continual motion, the impression, when once immersed, will be fixed.

During that time, and while attending to anything else, watch its color; and at the end of ten minutes or a quarter of an hour, take it out of the bath and dry it.
Agent for Neutralizing Bromine, Chlorine, and Iodine Vapors .-- Aqua ammonia, sprinkled about the chemical or coating room, will soon neutralize all the vapor in the atmosphere of either chlorine, bromine, or iodine.