2. The substances capable of being employed by the house and sign painter, comprise a great variety of articles, derived from the mineral, vegetable, and animal kingdoms; but he ordinarily confines his selection to but few, among which are white lead, litharge, Spanish brown, yellow ochre, chrome yellow, red ochre, terra di sienna, lampblack, verdigris, linseed-oil, spirits of turpentine, and gold-leaf. 3. White lead and litharge are manufactured in great quantities at chemical works, sometimes established for the express purpose of making these and some other preparations of lead. The substances of which we are now speaking, are produced in the following manner: the lead, in form of a continued sheet, about three feet long, six inches wide, and one line in thickness, is wound spirally up in such a manner, that the coils may stand about half an inch apart. 4. The metal in this form is placed vertically in earthen vessels, at the bottom of which is some strong vinegar. These vessels, being placed in sand, horse manure, or tan, are exposed to a gentle heat, which causes the gradual evaporation of the vinegar. The vapor thus produced, assisted by the oxygen which is present, converts the exposed surface into a carbonate of lead, the substance known as white lead, or ceruse. 5. The corrosion of one of these sheets occupies from three to six weeks, during which time it is repeatedly uncoiled and scraped. Litharge, or flake white, is nothing more than the densest and thickest scales produced in the manner just described. It can be obtained in a pure state from the dealers in paints, whereas the white lead of commerce is most commonly adulterated with chalk. 6. Spanish brown, yellow ochre, and terra di sienna, are earths impregnated with iron in different degrees of oxydation. Red ochre is yellow ochre burned. Chrome yellow is extensively manufactured in Baltimore, from the chromate of iron, found near that city. In chemical phraseology, the manufactured article is the chromate of lead, since the chromate is separated from the iron by the aid of a solution of the nitrate or acetate of lead. 7. Linseed-oil is obtained from flax-seed by pressure. It is afterwards filtered, and then suffered to remain at rest, to precipitate and clarify. This oil improves in quality by keeping, as it becomes, in a few years, as transparent as water. In this state, it is employed in the finest painting. 8. Before the oil is used, it is commonly boiled with a small quantity of litharge and red lead, to cause it to dry rapidly, after the paint has been applied. During the boiling, the scum is removed as fast as it rises, and this is mixed with inferior paints of a dark color. Linseed-oil, thus prepared, is vended by dealers in paints, under the name of boiled oil.