Linseed oil is mixed with powdered litharge, and heated till it becomes thick. A pale drying oil is obtained by mixing with linseed oil, sufficient dry sulphate of lead to form a milky liquid, and shaking it repeatedly for some days, letting it stand exposed to the light. When it has become quite clear, it may be poured off from the dregs. The sulphate of lead, when washed from the mucilage, may be again used for the same purpose. Liebig directs 1 lb. of acetate of lead to be dissolved in half a gallon of rain-water, and 1 lb. of finely powdered litharge added: the mixture is either boiled, or exposed for a longer time to a moderate heat, and frequently stirred, till no more particles of litharge can be seen. A white deposit is formed, which may be left in the liquid or separated by filtration; 20 lbs. of linseed oil, in which 1 lb. of levigated litharge has been diffused, are gradually added to the lead solution, previously diluted with an equal bulk of water, and the mixture frequently stirred. It is then left to clear itself in a warm place; but to obtain it bright it must be filtered through coarse paper or cotton. It may be bleached by exposure to the sun. The lead solution which subsides from the mixture may be filtered and used again, after dissolving it in 1 lb. of litharge as before. The oxide of lead contained in the oil may be removed from it by agitating it with diluted sulphuric acid, and letting it stand to settle. See also Oils (Linseed Oil, refined).