The inside of the cone, into which you pour the melted metallic mass, must be greased with tallow, to prevent its sticking thereto, and that it may come easily out. Striking the floor, on which the cone with the melted metal stands, helps the precipitation and descent of the Regulus of Gold and Antimony to the bottom of the cone. Less fire is requisite to melt this compound Regulus, in order to add fresh Antimony, than was necessary before the Gold was mixed with the reguline part of the Antimony; because this metallic substance, being much more fusible than Gold, promotes its melting. The Antimony is mixed with the Gold by repeated projections, that the separation of the metals may be accomplished with the greater ease and accuracy. Yet the operation might be successfully performed, by putting in all the Antimony at once, and with one melting only. The metalline mass found at the bottom of the cone after all these operations, is a mixture of Gold with the reguline part of the Antimony. All the rest of the process consists only in separating this reguline part from the Gold. As Gold is the most fixed of all metals, and as the Regulus of Antimony cannot bear the violence of fire without flying off in vapours, nothing more is necessary for this purpose but to expose the compound, as directed in the process, to a heat strong enough and long enough continued, to dissipate all the Regulus of Antimony. This semi-metal exhales in the form of a very thick white smoke. It is proper to blow gently into the crucible during the whole operation; because the immediate contact of the fresh air incessantly thrown in promotes and considerably increases the evaporation: and this is a general rule applicable to all evaporations. The fire must be gradually raised as the Regulus of Antimony is dissipated, and the operation draws towards an end; because the mixed mass of Regulus of Antimony and Gold becomes so much the less fusible as the proportion of the Regulus is lessened. Though the Regulus of Antimony be separated from the Gold in this operation, because the latter is of such a fixed nature that it cannot be volatilized by the degree of fire which dissipates the Regulus; yet, as the Regulus is very volatile, it will undoubtedly carry up some of the Gold along with it, especially if you hurry on the evaporation too fast, by applying too great a degree of fire, by blowing too briskly into the crucible, and still more if you evaporate your mixture in a broad flat vessel instead of a crucible. All these things must therefore be avoided, if you would lose no more Gold than you needs must.