by the Fire, without the trouble and charge they are fain to be at to sever them. Whereas they may be very easily parted by the Affusion of Spirit of Nitre or Aqua fortis (which the French therefore call Eau de Depart:) so likewise the Metalline part of Vitriol will not be so easily and conveniently separated from the Saline part even by a violent Fire, as by the Affusion of certain Alkalizate Salts in a liquid Form upon the Solution of Vitriol made in common water. For thereby the acid Salt of the Vitriol, leaving the Copper it had corroded to joyn with the added Salts, the Metalline part will be precipitated to the bottom almost like Mud. And that I may not give Instances only in De-compound Bodies, I will add a not useless one of another kinde. Not only Chymists have not been able (for ought is vulgarly known) by Fire alone to separate true Sulphur from Antimony; but though you may finde in their Books many plausible Processes of Extracting it, yet he that shall make as many fruitless Tryals as I have done to obtain it by, most of them will, I suppose, be easily perswaded, that the Productions of such
