Filter through paper, and add chloride of iodine one half ounce, bromine sufficient to take it up, which is a little less than half an ounce.
Charge with one of quick to six of water; coat over iodine to a soft yellow, nearly, but not quite, bordering on a rose; over quick to a dark purple, or steel, and back one sixth to one tenth.
Wolcott's American Mixture .-- Van Loan Quick .-- This mixture was first formed and used by T.Wolcott & Johnson and gained great celebrity for its productions.

I have now a bottle hermetically sealed that contains about a half ounce of this mixture prepared in 1841 by John Johnson, now a resident of this city, and the former partner of Mr.Wolcott.
The preparation of this mixture, as furnished by Mr.Johnson himself, is given as follows: "One part of bromine, eight parts of nitric acid, sixteen parts of muriatic acid, water one hundred parts.

This mixture should be allowed to stand for several days; it improves by age.
"Use .-- A few drops say, 6 to 12, of this mixture, should be put into about 6 or 8 ounces of water; it will require frequent replenishing by the addition of a few more drops.

The plate should be coated over the dry iodine to a red just bordering on a slate, and then exposed to the mixture only sufficiently long to change the color.

If this is not done in less than six seconds it is not strong enough.