1 62 Mayow 



union with the alkaline salt, ascends under a heat no 

 greater than is required for the rectification of the 

 spirit of nitre ; while in other circumstances the 

 same spirit of nitre is sundered only with difficulty 

 from its union with fixed salt, and requires a very 

 intense heat for its distillation. 



It is a corroboration of this view that the mass left 

 in the retort after a distillation of this kind, closely 

 resembles vitriolated tartar, and can be properly sub- 

 stituted for it. For since the alkaline salt of which 

 nitre is in part composed, differs scarcely at all from 

 salt of tartar, a union of that salt with oil of vitriol 

 will produce an acido-saline salt, differing not much 

 from vitriolated tartar. 



Nor is it mutually among themselves only that 

 salts strive after union, but also with other things ; and 

 from them they part so as to combine with a salt 

 more concordant with themselves. For example, any 

 acid spirit at once attacks metals and combines with 

 them to form vitriol. But if salt of tartar be poured 

 upon these vitriols dissolved in water, the acid salt of 

 the vitriols immediately combines with the salt of tartar, 

 and the metal, freed from the fetters of the acid salt, 

 will fall headlong to the bottom. 



As an acid salt combines with metals, so also does 

 an alkaline salt with sulphur. If, however, an alkaline 

 salt in union with sulphur be dissolved in water, and 

 then any acid spirit be poured into the solution, the 

 fixed salt will instantly rush into union with the 

 acid salt ; and the sulphur, meanwhile, liberated from 

 its union with the fixed salt, and rising in aerial form, 

 will indicate its presence by its fetid odour — as 

 happens when sulphur dissolved in lye is precipitated 

 by the addition of an acid liquid. 



Nor is it with an alkali only but also with the 



