Practical Magazine 21, 1876
(Chemistry applied to the Arts, Manufactures, &c.)
A black varnish, composed as follows, is found useful for gas meters and other metal articles: —
44 lbs. of pitch or tar, and 11 lbs. of india-rubber or gum elastic are boiled till the whole is reduced to about 33 lbs. When it is required for use, it is diluted with water, and well stirred.
- El Porvenir de la Industria, July 7, 1876.
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