Paper coated with glass is known by this name just as paper coated with tine sharp sand is called sandpaper, and paper coated with emery is called emery paper. Paper or a cheap cloth is coated with thinnish glue, dusted heavily and evenly with glass-powder of the proper fineness, and allowed to become nearly dry. The superfluous powder is then shaken off, the sheets are pressed to make them even, and afterwards thoroughly dried.

The objection to ordinary glass-paper is that it is easily injured by heat and moisture. If the glue be mixed with a little bichromate of potassa before it is applied to the cloth, and exposed for some time to strong bright sunshine while it is drying, it will become insoluble in water.

The glue may also be rendered insoluble by the process of tanning. The paper or cloth is first soaked in a solution of tannic acid and dried. The glue is then applied, the powdered glass dusted on, and over it is dusted a little tannic acid. If the glue be not very moist, it should be damped by means of an atomiser, a very cheap form of which is figured in The Young Scientist, vol. 2. The sheets are then slowly dried and will be found to resist moisture very thoroughly.