Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Drawing Ink
A very black and indelible drawing ink. may be made by dissolving shellac in a hot water solution of borax, and rubbing up in this solution a fine quality of Indian ink. After using, dip the drawing pen in alcohol, and wipe dry to keep it clean and bright. (See No. 2514.) 2532. Permanent Ink for Use with Stamps or Type. Mix equal parts black oxide of manganese and hydrate of potash, heat to redness, and rub with an equal quantity of smooth white clay into a paste, water being added for the purpose. Or: Sulphate of manganese, 2 drachms; lampblack, 1 drachm; powdered loaf sugar, 4 drachms; rubbed into paste with water. After stamping, dry the linen and wash well in water. 2533. Sympathetic, or Invisible Inks, for Secret Writing. These are colorless inks which require the aid of heat or some 2540. Sympathetic Inks Developed by Heat. There are a number of colorless substances that may be used as inks, which are developed by the application of heat only. in equal parts, will become yellow if exposed to the fire.
Onion juice has the same property as the above mixture.
Lemon juice, a very weak solution of either aquafortis, oil of vitriol, common salt, or saltpetre, will turn yellow or brown on exposure to the fire.
A weak solution of chloride of cobalt and chloride of nickel is turned a beautiful green by heat.
A solution of chloride or nitro-muriate of cobalt, turns green when heated, and disappears again on cooling. A dilute solution of chloride of copper becomes a fine yellow at a moderate heat, and disappears on cooling.
A solution of acetate of cobalt, with a little nitrate added to it, turns rose-colored by heat, and disappears again when cold.
These last, which disappear again on cooling, are the best sympathetic inks for purposes of correspondence, as the others are other agency to develop the characters written more or less indelible when once developed. with them. Their use has been rendered 2541. Hoe's Composition for Printing specially practical since the recent introduc- Ink Rollers. This consists of glue and moof glue and motion of the postal correspondence cards in lasses, the proportions varying from 8 pounds England and elsewhere. By previous ar- of glue in summer to 4 pounds in winter, for rangement between correspondents, the re- each gallon of molasses. The glue should ceiver of a card only needs some visible sign be placed for 1 an hour in a bucket, covered be placed for an hour in a bucket, covered with water, then pour the water off and allow the glue to soften. Put it into a kettle and heat it until thoroughly melted; if too thick, on the card to identify the writer or sender; this will at once suggest the means to be employed to develop the particular ink the receiver's correspondent has agreed to use. a little water may be added. Lastly, the mo-