The following are recipes for white inks. White egg-shells are powdered in a mortar with clean water, and the powder is dried. Dissolve 1 part of white gum ammoniac in3 parts of acetic acid; a gentle heat will aid this. Strain through muslin, and add 1 part of powdered egg-shell. To thin the ink, dilute with acetic acid. Write with a quill pen or sable brush. Pure whiting or Chinese white may be substituted for the egg-shell. Another and simpler recipe is to mix with a weak solution of arabic gum any one of the following. Flake white, French zinc white, white-lead, freshly precipitated barium sulphate, starch, or magnesium carbonate. The white substance must be reduced to an impalpable powder before mixing.