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Dead-White Enamel

For white enamel, the articles must be perfectly free from foreign admixture, as this would impart a color.

When well managed, either of the following forms will produce a paste that will rival the opal.

Calcine (from 2 parts of tin and 1 part of lead calcined together), 1 part; fine crystal or frit, 2 parts; a very trifling black ground, by the following process: Clean the copper with sand and sulphuric acid, and then apply the following mixture: 2 parts white arsenic, 4 parts hydrochloric acid, 1 sulphuric acid , and 24 water. etc. The fine enamels of trade are generally 2401. Enamel for Labels, Signboards, prepared by fusing at high temperatures, silica, oxide of tin, and oxide of lead, and spreading the mixture over the surface of a sheet of copper, gold, or platinum. The objections to these enamels are, in the first place their high cost, and secondly the impossibility E. Duchemin has advantageously replaced of giving them a perfectly flat surface. Mr. them by the following economical and efficient compound : 2402. Duchemin's Enamel for Labels, 30 parts; silica (fine sand), 90 parts; litharge, etc. Arsenic, 30 parts by weight; saltpetre, ; saltpetre, of the required shape and size, care being 250 parts. This is spread on plates of glass taken, however, that the kind of glass en:ployed be not inferior in point of fusibility to the enamel.

Enameled glass prepared from the above substances may be drawn or written on as readily as if it were paper, and in less time than one minute the writing may bo rendered indelible by simply heating the plate autographs, legal acts, public documents, hiin a small open furnace or muffle.

Drawings, torical facts and dates of importance, labels for horticultural purposes or destined for outof-door exposure, coffin plates, signboards, show-case signs, etc., may thus be cheaply for ages. First-class photographs, either posmade, which will resist atmospheric influence3 itives or negatives, may be taken on such cramels without collodion. (See Photographs on Enamel. on Enamel.) The enamel of iron hollow ware is made of 2403. Enamel for Iron Hollow Ware, powdered flints, ground with calcined borax, fine clay, and a little feldspar. This mixture and pour the fused mass into clean water; over the pots after they have been scoured dry, powder, and again fuse, and repeat the with diluted sulphuric acid and rinsed clean whole process 3 or 4 times, observing to avoid with water. contamination with smoke, dirt, or oxide of dusted over with a glaze composed of feldspar, While still moist they are quantity of manganese; powder, mix, melt, is made into a paste with water and brushed iron.