t 48 ] 



cufed from the afhes of fea weeds by burning," 

 This fait is the natrum of the ancients. 



b. Vegetable alkali, procured chiefly from the 

 afhes of land vegetables, whence are produced 

 pearl afhes, pot afhes, C#r. 



tr. Volatile alkali is diftinguifhed from the other 

 two by its volatility, as it evaporates by heat 

 before it becomes fluid. It is procured from 

 putrid fubftances, particularly animal, and alfo 

 from fome fubterraneous fires, the urine of ani- 

 mals, all horny and bony fubftances, and plenti- 

 fully from foot. 



B. Mineral acid salts turn the fyrup of 

 violets, or an infufion of purple flowers, of a red 

 color; they effervefce with alkaline falts, and 

 are only obtained in a fluid ftate. 



a. Vitriolic acid, or oil of vitriol, fo called from 

 vitriol or copperas, which contains this acid 

 united with iron-, is heavier than water, and 

 colorlefs when pure. With the principle of 

 inflammability it forms fulphur, from whence 

 this acid is chiefly procured. 



b. Nitrous acid, or aqua fortis, is of an orange 

 tawney color. Expofed to the air, it emits 

 fumes of a fiery color. 



c. Muriatic acid, or fpirit of fea fait, is a color- 

 lefs tranfparent fluid. Expofed to the air, its 

 fumes are white. 



d. Acid of fpar, is feparated from the fluor 

 (Cronftadt*s Mineralogy, p. 109.) This newly 

 difcovered acid united with calcareous earth, 

 forms the fparry flu or, from whence it may be 

 difengaged by oil of vitriol, and the other mine- 

 ral acids, which have a ftronger affinity with 

 calcareous earth. In fmell and color the acid 

 of fpar refembles the muriatic acid, but with 



calcareous 



