3123. Soap Marble for Books

3123.     Soap Marble for Books. This is applicable for marbling stationery, book edges, or sheets of paper for ladies' fancy work. Grind, on a marble slab, Prussian blue, with water, and a little brown soap, to a fine pliable consistence, that it may be thrown on with a small brush. Grind King's yellow in the same manner, with water and white soap. "When green is intended for the ground color, grind it with brown soap, and King's yellow with white soap. Lake may be used for a ground color, and Prussian blue ground with white soap; brown umber for a ground color, and flake-white ground with white soap. Any color of a light substance may be ground for marbling.

3124. Spotted Marble for Books

3124.      Spotted Marble for Books.

After the fore-edge of the book is cut, let it remain in the press, and throw on linseeds in a regular manner; sprinkle the edge with any dark color, till the white paper is covered, then shako off the seeds. Various colors may be used. The edge may be colored with yellow or red before throwing on the seeds and sprinkling with blue. The seeds will make a fine fancy edge when placed very thick on different parts, with a lew slightly thrown on the spaces between.

3125. Brown Sprinkle for Leather Book-Covers

3125.    Brown Sprinkle for Leather Book-Covers. Pearlash or potash, 1 part; soft water, 4 parts. Dissolve and strain.

3126. Red Sprinkle for Binders

3126. Red Sprinkle for Binders. Brazil wood (ground), 4 parts; alum, 1 part; vinegar, 4 parts; water, 4 parts. Boil until reduced to 7 parts, then add a small quantity of loaf-sugar and gum. Bottle for use.

3127. Black Sprinkle for Leather Book-Covers

3127. Black Sprinkle for Leather Book-Covers. Green copperas, 1 part; soft water, hot, 6 parts. Dissolve.

Photography. Photography is based upon the law or principle that sunlight decomposes certain combinations of the salts of silver. For instance, if a piece of paper is first dipped into a solution of chloride of sodium (common table salt,) and then, when dried, floated on a solution of nitrate of silver, it will, upon being brought to the light, begin to darken, and finally assume an absolute black. It will be seen that if any opaque or semi-opaque body is interposed between the light and the paper, that portion which is so protected from the action of the light remains white, and thus impresses upon the paper, in a negative condition, the form or figure of the article so used.