"The power, therefore, of the strongest Emetic Tartars," continues he, "depends on the quantity of Regulus of Antimony dissolved by the Cream of Tartar, and the nearer the preparations of Antimony, on which the solution of Cream of Tartar is boiled, are to the form of a Regulus or a Glass, the more violent is the Emetic Tartar; because the Vegetable Acid of the Tartar acts then more immediately upon the Emetic part of the Antimony, and dissolves more of it."
Mr. Geoffroy found upon trial, that Cream of Tartar boiled for a due time on Crude Antimony, doth indeed dissolve a little of the reguline part thereof; but that the quantity of Regulus dissolved thereby is so very small, that the Emetic Tartar produced is extremely weak. The gross Sulphur, in this case, hinders the Cream of Tartar from acting on the reguline part with so much efficacy, as when the Antimony is properly prepared by freeing it entirely from its redundant Sulphur.
Nothing can be added to what Mr. Geoffroy hath said on this subject. His experiments are decisive, and set the truth he intended to prove in the clearest light.
Mr. Hoffman affirms, that Emetic Tartar loses part of its virtue by being boiled too long. A very able Chymist goes so far as to say, that Tartar ought not to boil above six or seven minutes with prepared Antimony; because longer boiling destroys part of its Emetic quality. Can this arise from hence, that Cream of Tartar, after dissolving a certain quantity of the reguline substance, separates from it afterwards? Or is the Cream of Tartar itself decomposed by too long boiling? This deserves to be particularly inquired into, as well as the nature of the Metallic Salt, which results from the union of the Acid of Tartar with the Regulus of Antimony.
Crystal of Tartar acts also on several other metallic substances, and particularly on Lead; with which it forms a Salt, resembling Tartarized Tartar in the figure of its crystals.
[CHAP. V.]
Of the Product of Acetous Fermentation.
PROCESS I.
Substances susceptible of the Acetous Fermentation turned into Vinegar.