Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Home › The Art Of Dyeing › To prepare Catechu
To prepare Catechu
To 7 or 8 gallons of water put 1 pound of catechu, and boil till it is all dissolved; then add 2 ounces of sulphate of copper, stir, and it is ready for use. Nitrate of Copper may also be used, taking 1 wine-glassful of the solution made according to the next receipt. 97. To make Nitrate of Copper Solution. To 1 part by measure nitric acid, and 2 parts water, add metallic copper so long as the acid will dissolve it, then bottle the solution for use.