It begins to flow as soon as it is moderately red; but, like the other Semi-metals, it cannot stand a violent degree of fire; being thereby dissipated into smoke and white vapours, which adhere to such cold bodies as they meet with, and so are collected into a kind of _farina_ called _Flowers of Antimony_. If Regulus of Antimony, instead of being exposed to a strong fire, be only heated so moderately that it shall not even melt, it will calcine, lose its phlogiston, and take the form of a greyish powder destitute of all splendour: this powder is called _Calx of Antimony_. This calx is not volatile like the Regulus, but will endure a very violent fire; and being exposed thereto will flow, and turn to a glass of the yellowish colour of a hyacinth. It is to be observed, that the more the Regulus is deprived of its phlogiston by continued calcination, the more refractory is the calx obtained from it. The glass thereof has also so much the less colour, and comes the nearer to common glass. The calx and the Glass of Antimony will recover their metalline form, like every other Calx and Glass of a metal, if reduced by restoring to them their lost phlogiston. Yet if the calcination be carried too far, their reduction will become much more difficult, and a much smaller quantity of Regulus will be resuscitated. Regulus of Antimony is capable of dissolving the metals: but its affinities with them are various, and differ according to the following order. It affects Iron the most powerfully, next Copper, then Tin, Lead, and Silver. It promotes the fusion of metals, but makes them all brittle and unmalleable. It will not amalgamate with Mercury; and though by certain processes, particularly the addition of water and continued trituration, a sort of union between these two substances may be produced, yet it is but apparent and momentary; for, being left to themselves and undisturbed, they quickly disunite and separate[2]. [2] M. Malouin, however, hath found a way to unite these two metallic substances: but then he does it by the interposition of sulphur; that is, he combines crude Antimony with Mercury. This combination is brought about in the same way that Æthiops Mineral is made; _viz._ either by fusion, or by trituration only without fire. It resembles the common Æthiops, and M. Malouin calls it _Æthiops of Antimony_. He observed that Mercury unites with Antimony much more intimately, by melting, than by rubbing them together. The vitriolic acid, assisted by heat, and even by distillation, dissolves Regulus of Antimony. The nitrous acid likewise attacks it: but the solution can by no art be made clear and limpid: so that the Regulus is only calcined, in a manner, by this acid.