Printers’ Ley.—No. 3.—Table salt 2 oz., unslacked lime 2 lb., Scotch washing soda (bruised) 2 lb. Put together in 3 gallons of water, stir well; when settled, ready for use.
Note.—This ley, if prepared carefully, is very strong, and will wash off almost any colour.
A Strong White Paste.—Dissolve 2½ oz. of gum-arabic in 2 quarts of water, and stir it into 1 pound of wheat flour until the whole becomes of a pasty consistency. It is then to be heated, and 1½ oz. each of sugar of lead and alum dissolved in a little water added thereto, and the composition well stirred until it shows signs of boiling, when it must be removed from the fire. Add while hot 6 drops of carbolic acid. This is a very tenacious and durable paste, and may be used on almost any substance.
Pastes for Fixing Labels on Glass.—No. 1.—Take of gum-arabic 1 oz., boiling water and glycerine 2 fluid ounces each. Make a solution.
No. 2.—Take of gum-arabic and powdered gum tragacanth ½ oz. each, water 1½ oz., acetic acid 20 drops. Mix. The acid is used to prevent chemical change, although a stiff paste made of tragacanth alone is not inclined to spoil by fermentation.
To Make a good Mucilage.—The best quality of mucilage is made by dissolving clear glue in equal volumes of water and strong vinegar, and adding one-fourth of an equal volume of alcohol, and a small quantity of a solution of alum in water. The action of the vinegar is due to the acetic acid which it contains. This prevents the composition from gelatinizing by cooling; but the same result may be accomplished by adding a small quantity of nitric acid. Some of the preparations offered for sale are merely boiled starch, or flour, mixed with nitric acid to prevent the gelatinizing.