part m. Metallic Preparations. — Antimony. 6**

iron pot heated to whiteness, assiduously stirring until the mix-ture acquire an ash colour. Take them out, and pulverize them ;and then put them into a coated crucible, over which anothercrucible, having a small hole in its bottom, is to be inverted andluted. Then place it over the fire, which is to be graduallyraised, so that it may continue at a white heat for two hours.Triturate the residue into very fine powder."

Oxidum Antimonii cum Phosphate Calcis ,• olim,Pulvts antimonialis, Edin. Oxide of Antimony withPhosphate of Lime ; formerly Antimonial Powder.

" Take of sulphuret of antimony in coarse powder, harts-horn shavings, each equal parts. Mix, and throw them intoa wide iron pot heated to redness, and stir them assiduouslyuntil they are burnt into a matter of a grej' colour, which re-move from the fire, rub to powder, and put into a coated cru-cible, over which another crucible having a small hole in itsbottom is to be inverted and luted: then apply the fire,which is to be gradually raised to a white heat, and kept at thisincreased heat for two hours. Finally, reduce the matterwhen it is cold to a very fine powder."

Puxvis antimonialis, Dub. Antimonial Powder." Take of sulphuret of antimony in coarse powder, harts-horn shavings, each two pounds. Boil the hartshorn in a suf-ficient quantity of water to separate the gelatin; then dry it,and mix it with the antimony. Throw the mixture into awide iron pot heated to redness, assiduously stirring until thesulphurous vapours cease to be extricated, and the matter ac-quire a grey colour. Rub the mass to powder when it is cold,and put it into a coated crucible; over which invert anothercrucible having a small hole in its bottom, and lute the twofirmly together. Roast the matter with a heat gradually raisedto whiteness for the space of two hours; and lastly, when it iscold, grind it to a very fine powder."

In these processes, by the first exposure of the materials tothe action of heat, the gelatin and the other principles of thehartshorn, except the phosphate of lime, are decomposed anddissipated; the sulphur of the sulphuret of antimony is at thesame time expelled, and the metal is partially oxidized, theoxidizement being favoured by the shape of the vessel and fre-quent stirring. By the subsequent application of heat, theoxitlizement of the metal is rendered more complete, and theoxide is partially vitrified ; but whether the phosphate of limeis merely mechanically mixed with the oxide, or the lime yieldsup part of the phosphoric acid to it, and a ternary compoundof phosphate of lime and of antimony be thus produced, is un-certain. From the experiments of Chenevix, however, theformer supposition seems to be more probable. In the Dublin

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