Important: Safety Warning
This page contains a formula or preparation using substances now known to be dangerously toxic, such as arsenic, mercury, lead, or cyanide compounds. Exposure to these substances can cause severe poisoning, permanent injury, or death.
In addition, 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.
New Blue
Mix equal parts of common arseniate of copper (see Mineral Green, No. 2711), and neutral arseniate of potash, fuse by heat in a large crucible, then add to the fused salt 1/6 its weight of nitre.
Effervescence takes place, and the salt becomes blue. Cool, pulverize, and wash.