LEAD. See that article (Encycl.), and CHEMISTRY-Index in this Supplement. It is well known, that lead generally contains a portion of silver, and sometimes of gold; and that there are occasions, particularly in assaying, when it is of importance to have it freed from these metals. For accomplishing these purposes different processes have been proposed; but the following by Pet. Jac. Hjelm, as it is the least expensive, promises to be the most useful: