~Solution.~--Ores, &c., containing antimony are best opened up by boiling with hydrochloric acid or aqua regia; treatment with nitric acid should be avoided wherever possible, since it forms antimonic acid, which is subsequently dissolved only with difficulty. Salts of antimony in solution have a tendency to form insoluble basic salts; so that care must be exercised in diluting. Compounds such as antimonite which are soluble in hydrochloric should be dissolved at once in that acid. ~Separation.~--To the solution add potash in excess and a little free sulphur, and pass a current of sulphuretted hydrogen for some minutes; allow to digest for an hour or so on a hot plate; filter; and wash the residue. Acidulate the filtrate with hydrochloric acid: the precipitate will contain the antimony (as Sb_{2}S_{5}), and possibly arsenic or tin. The precipitate is transferred to a beaker and boiled with hydrochloric acid; the solution is filtered off and diluted. Add a few crystals of tartaric acid, and pass a current of sulphuretted hydrogen for some time. The first flocculent precipitate will become denser, and render the filtering more easy. Transfer the precipitate (after washing free from chlorides) to a Berlin dish, and treat cautiously with fuming nitric acid. The action of this acid on the sulphide is very violent. Evaporate and ignite, transfer to a silver dish, and fuse with four or five times its weight of caustic soda, cool and extract with a little water, then add an equal volume of alcohol, and allow to stand overnight. Filter, wash with dilute alcohol. (The filtrate will contain the tin.) The residue contains the antimony as antimonate of soda, and is dissolved off the filter with hot dilute hydrochloric, with the help of a little tartaric, acid. The filtrate is now ready for the gravimetric determination. GRAVIMETRIC ASSAY. Pass a current of sulphuretted hydrogen through the solution containing the antimony to which a little tartaric acid has been previously added. Pass the gas till the precipitate becomes dense, and the antimony is all down. The solution must not be too strongly acid. Filter off the precipitate, wash with hot water, dry in the water oven, transfer to a weighed porcelain dish, and cautiously treat with fuming nitric acid. Continue the action on the water bath till the sulphur and antimony are completely oxidised. Evaporate; ignite, gently at first, then strongly over the blast; cool, and weigh. The residue is a white infusible powder, and consists of antimony tetroxide, Sb_{2}O_{4}, containing 78.94 per cent. of the metal. ~Determination of Antimony as Bigallate.~--What appears to be a very good method has been worked out by M.A. Guyard, and is described in Crookes' _Select Methods_, p. 398.