A simple method for detecting arsenic in paper, cards, etc., is described as follows:—Immerse the suspected paper in strong ammonia on a white plate or saucer; if the ammonia becomes blue, the presence of salt of copper is proved; then drop a crystal of nitrate of silver into the blue liquid, and, if any arsenic be present, the crystal will become coated with yellow arseniate of silver, which will disappear on stirring.
An Ink Restorer.
The process consists in moistening the paper with water and then passing over the lines in writing a brush which has been wet in a solution of sulphide of ammonia. The writing will immediately appear quite dark in color, and this color, in the case of parchment, it will preserve.
Colors for Holding Bronze.
Red and green inks are good colors for holding bronze, when you are not working with size or varnish.
Stencil Ink.
A good and cheap stencil ink in cakes is said to be obtained by mixing lampblack with fine clay, a little gum arabic or dextrine, and enough water to bring the whole to a satisfactory consistence.
Copying Ink to be Used Without Press or Water.
Well mix three pints of jet-black writing ink and one pint of glycerine. This, if used on glazed paper, will not dry for hours, and will yield one or two fair, neat, dry copies, by simple pressure of the hand, in any good letter copy-book. The writing should not be excessively fine, nor the strokes uneven or heavy. To prevent “setting off,” the leaves after copying should be removed by blotting-paper. The copies and the originals are neater than where water is used.