Ink

a writing fluid. Good ink should be free from sediment. When applied to paper it should penetrate so as to be difficult of erasure, but it should not have a tendency to spread. It should not fade with age. It is desirable also that ink should not have a tendency to mold, and that it should not corrode a steel pen. Black inks are, at base, usually iron or logwood. The former are the best.

A famous recipe for black ink is the following. One part by weight of bruised nut galls; six parts of soft water; boil three hours in a copper kettle, replacing from time to time the water lost by evaporation. After settling, draw off, leaving the dregs behind, and add one-half part of common gum senegal and a half part of green vitriol. Thin with water to the required consistency. Allow the mixture to stand until it is nearly black; then bottle tight and put away for use as wanted. Logwood ink is made easily. Logwood may be boiled in soft water, or else extract of logwood may be used. When ink of a proper consistency has been obtained add one part in ten of ammonia or alum dissolved in boiling water. This gives a violet ink.

Red ink may be prepared by dissolving carmine in a solution of caustic ammonia. It evaporates very rapidly, however, and must be kept in closely stoppered bottles. A better red ink for ordinary purposes is made by steeping cochineal in hot soft water.

A blue ink may be compounded without difficulty by mixing one part of oxalic acid with eight parts of Prussian blue, and adding the mixture to water until the desired intensity of color is obtained.

India ink is prepared by the Japanese from pine soot and the lampblack of sesamum oil. This they mix with a liquid glue obtained from the hides of cattle. It is manufactured in sticks or cakes. It is used by artists, architects, engineers, and others who desire a superior ink for drafting purposes. A liquid obtained from the cuttlefish is used also for the same purpose. The indelible ink used by the housewife for marking linen may be made from silver nitrate, dissolved in water and ammonia.

For sympathetic ink, see COBALT. Printer's ink is so thick and sticky that it is hardly an ink. It is a superior paint. It consists chiefly of linseed oil, soap, lamp black, and naphtha. Vermilion is used as coloring for red ink; ultramarine for blue, and red chromate for yellow.

An outworn typewriter ribbon put to soak in soft water produces excellent ink.