1867 Six Hundred Receipts by John Marquart

600 MISCELLANEOUS VALUABLE RECEIPTS.

116

is better adapted for distemper. Its colour may be obtained in oil by mixing two or three parts of ver- digris witli one of white lead. Green Lake^ or Venetian Emerald. — A very simple mode has recently been discovered, at Venice, of pro- ducing a fine unchangeable emerald colour. A quan- tity of coffee is boiled in river-water, — if spoiled cof- fee, so much the better. The green lake obtained by this process is said to have resisted the action of acids, and even the infi.uence of light and moisture. Browns. — Umber, or, as it is sometimes called, brown ochre, is an impure native oxide of iron and manganese. It is much employed by painters, and is the only simple brown in common use. JVew Brown, discovered by Mr. Hatchet. This celebrated chemist has suggested to painters that a simple brown colour, far superior in beauty and intensity to all the browns, whether simple or com- pound, hitherto known, may be obtained from the prussiate of copper, (a combination of prussic acid with copper.) The following is the process which he recommends : Dissolve the green muriate of copper in about ten times its weight of distilled or rain water, and add a solution of prussiate of lime, until a complete pre- cipitation is effected. The precipitate is then to be washed with cold water, filtered, and set to dry in the shade. No. 227. Of different Oils used in Painting and Varnishing. Oil of Spike is, if pure, a volatile oil, and has the advantage of drying more quickly than any other

fat-oil.