In France a solution of lead is first prepared by adding at least 174 pounds of finely ground litharge to 65 pounds of pyroligneous acid, of such strength that 22 grains and a half of this acid may saturate 25 grains of well crystallized subcarbonate of soda; 15 to 20 times as much water is usually added. The whole is left for a short time, and the clear being poured off, some fresh acid and water is poured on the sediment, to take up any oxide that might have escaped the action of the first parcel.,,The clear solution decanted off the residuum is run in large, but shallow, covered cisterns, and carbonic acid is passed into these cisterns by a large number of pipes. This carbonic acid gas is procured by the burning of charcoal in a close stove, and passing the burnt air into a liquor. When no more settling appears to be formed,the whole is passed into a deep cistern, and left there for some hours, when the liquid part is poured off in order to be combined again with more litharge, some fresh acid being also added.,,Part of the sediment left in the cistern is well washed and produces a dull milk-white lead, with several portions of fresh water. Generally the washing is not continued to such exactness, because buyers prefer white lead that has a slight bluish tinge ; now the copper contained in the litharge produces the colour, provided the settling is not washed too much. A grey tinge is sometimes preferred ; which is produced by adding a small quantity of common ivory black, which must, however, be well mixed with the white lead.,,The white lead is then moulded by putting the welldrained mass into glazed pots of the proper shape to imitate that of the Dutch white lead leaves. These pots are then stoved, and the white lead packed in pale blue paper, the reflection of which gives it a more agreeable cast of colour.,,