100 antimony to form the grey oxide. Whether this is the protoxide or deutoxide may be disputed; and the facts known concerning the other oxide or oxides will scarcely determine the case: but the proportions of the muriate and sulphuret of antimony accord much better with the former supposition. Now if 18 ∶ 100 ∷ 7 ∶ 39, for the weight of the atom of antimony; I prefer the weight 40, deduced from the sulphuret, as announced in VOL. 1, page 264. The oxide which contains 30 on 100 must be 2 atoms of the deutoxide and 1 of the protoxide united. What Berzelius calls the white oxide or antimonious acid, may be 1 atom of each oxide united, containing 27 oxygen on the 100. The oxide supposed to contain 36 or 37 oxygen on 100, and which must be considered as the deutoxide, has not been proved to exist separately. My efforts to procure it have failed as well as those before mine: by treating muriate of antimony with oxymuriate of lime I have obtained oxides of 30 on the 100, but never much higher. Whenever a greater proportion of oxymuriate of lime is added, the smell of the gas becomes permanent. Antimony exposed to a red heat in a current of common air or oxygenous gas takes fire, and white fumes arise formerly called _flowers of antimony_; this oxide contains 27 or 30 oxygen on 100 metal. Antimony thrown into red hot nitre is oxidized rapidly; the remaining powder, washed in water, is found to be a compound of oxide of antimony and potash. Berzelius calls the oxide the antimonic acid, and the salt the _antimoniate of potash_. It consists, according to his experience, of 100 acid and 26.5 potash. A similar salt formed between the antimonious acid and potash is constituted of 100 acid and 30.5 potash. 19. _Oxide of tellurium._ We are chiefly indebted to Berzelius for the proportions in which tellurium combines. He finds 100 tellurium unite to 24.8 oxygen. Also that 201.5 tellurate of lead gave 157 sulphate of lead. This last contains 116 oxide of lead, which must therefore have combined with 85.5 of the oxide of tellurium. Hence 97 oxide of lead would combine with 71.5 oxide of tellurium = 57½ tellurium + 14 oxygen. Whether this oxide of tellurium is the protoxide or deutoxide, is somewhat uncertain. The atom of tellurium will weigh 57½ in the latter case, but only 28 or 29 in the former. The analogy of the oxide to acids favours the notion of a deutoxide; but the facility with which the tellurium is volatilized by hydrogen is in favour of the lighter atom. The oxide is a white powder; it is produced by dissolving the metal in nitro-muriatic acid and precipitating by an alkali. 20. _Oxides of arsenic._