The best of these do not differ in any essential particular mutually, nor from the white leads of other manufactories. The latter, being prepared from the flake white, is generally the greyest of the two. The inferior white leads are adulterated with whitening or sulphat of barytes and other earths, which injure them in body and brightness, dispose them to dry more slowly, to keep there places less firmly, and to discolour the oil with which they are applied. All the above are carbonates of lead, and liable to froth or bubble when used with aqueous, spirituous, or acid preparations. There are no better whites for architectural painting, and for all the purposes of common oil painting, they are kept in the shops under the names of best and common white leads ready ground in oil, and require only to be duly diluted with linseed oil and more or less turpentine according to the work; and also for mixing with other colours and producing tints.,