White Ink For Writing On Black Paper
Having carefully washed some egg-shells, remove the internal skin, and
grind them on a piece of porphyry. Then put the powder into a small
vessel of pure water, and when it has settled at the bottom, draw off
the water, and dry the powder in the sun. This powder must be
preserved in a bottle; when you want to use it, put a small quantity
of gum ammoniac into distilled vinegar, and leave it to dissolve
during the night. Next morning the solution will appear exceedingly
white; and if you then strain it through a piece of linen cloth, and
add to it the powder of egg-shells, in sufficient quantity, you will
obtain a very white ink.