Indelible Ink.—lndelible writing and marking inks are mostly divided carbon which, as is well known, offers great resistance to chem ical agents. India and China inks are of this class. They are composed of carbon, chiefly lampblack or other soot, mixed with gum or glue. In delible ink for marking textile fabrics is also made of nitrate of silver and other silver salts.
Various other substances are em ployed in ink making, but those we have given are the most common.
Treatment of Ink Stains.—If the nature of an ink is known, the proper treatment can, of course, be given; otherwise it is best to first dip the ink in water to test if nigrosine is present.
If nigrosine is not present try oxal ic acid, which will remove an old style iron-gall ink or decompose a modern iron-gall ink by removing the black tannate of iron, and leaving the in digo and aniline blue dye stuffs as a stain on the fabric. If this is not effective, try muriatic acid. This will remove the stain of a logwood or copying ink. Follow this with an al kali to remove the effects of the acid.
A nitrate of silver ink stain may be removed with cyanide of potas sium, which is a deadly poison.
Or apply a dilute solution of per manganate of potash with muriatic acid; follow by soaking in a solution of hyposulphite of soda, and after wards rinse in clear water.
If all else fails, cover the spot with dry bleaching powder and moisten with dilute acetic acid. Afterwards apply ammonia, or dip in a solution of hyposulphite of soda and rinse. It must be borne in mind that strong acids and alkalies will injure the tex ture of animal fibers as wool and silk and bleach colored fabrics. For such articles use pyrophosphate of soda.
If a garment spotted with ink is especially valuable it would be well to try a series of experiments with the same ink on a piece of similar fabric. In the meantime cover the stain with various dry absorbents to take up the excess of ink. After these have done their work, soak the article in milk while the experiments are being made.
Or if it is small dip it immediately into pure melted tallow.
Lemon juice and salt, sour milk, and similar remedies are useful if suitable acids are not at hand, but cannot be depended on to do the work in a thorough manner.