Indestructible Ink for Resisting the Action of Corrosive Substances.
On many occasions it is of importance to employ an ink indestructible by any process, and will not equally destroy the material on which it is applied. For black ink, 25 grs. of copal in powder, are to be dissolved in 200 grs. of oil of lavender, by the assistance of a gentle heat, and are then to be mixed with 2 1/2 grs. of lampblack and 1/2 gr. of indigo; for red ink use 120 grs. of oil of lavender, 17 grs. of Copal, and 60 grains of vermilion. A little oil of lavender or of turpentine may be added if the ink be found too thick. A mixture of genuine asphaltum dissolved in oil of turpentine or benzine, amber varnish and lampblack, would be still superior.
This ink is particularly useful in labelling phials, etc. containing chemical or corrosive substances.[link]