Copying Ink
The virtue of it is able to permeate the tissue of the linen, copying ink consists in its non-drying proso that the marks appear on both sides. It is perty. This property may be given to any advisable to mix the solutions together, only when the ink has to be used. It is perfectly indelible, and so easy to write with that the finest devices may be drawn with it. This ink has the advantage of being cheaper than the ink prepared from nitrate of silver. It has also another advantage over the latter salt, viz.: that it is chemically indelible. 2519. Liquid Silver, for Vellum, &c.
Take silver leaf and grind it with gum-water or glaire of egg. ordinary ink by the addition of sugar. Lately, however, glycerine has been substituted for sugar, and is decidedly to be preferred. A good copying ink may be made from common violet writing ink, by the addition of about 1 part glycerine to 100 parts of the ink. The addition of too large a proportion of glycerine is apt to impair the requisite drying qualities of the ink; and too little will fail to make the ink susceptible of a perfect copy. (See No 2471.)