5 . GYPSUM, 



Vitriolic Acid combined with calcarious 

 Earth. 



Synonymous Names. 



-Vitriol of lime. 

 Calcarious vitriol. 

 5. GYPSUM. {Selenite. 



Paris plaifter. 

 -Sulphate of lime. 



This fait abounds in nature, and therefore is 

 exceeding commonly found in fpring water ; but 

 fo fmall a quantity diffolves, that it gives very 

 little tafte to water. 



A. a. In waters, containing Gypfum, the earthy 

 bafis may be detected by a piece of paper, ftained 

 with decoction of Brazil wood, being dipped into 

 this water, will tinge it of a violet colour. 



b. If a little acid of fugar be added to water 

 containing it, the water will immediately be- 

 come turbid, and a white powder be depofited. 

 The acid of fugar has a ftronger attraction to 

 the calcarious earth than the vitriolic acid com- 

 bined with it, and forms faccharine felenite, a 

 fait extremely difficult of folution, therefore pre- 

 cipitated while the vitriolic acid remains diffufed 

 through the water. 



c. A folution of the cauftic vegetable alkali 

 being added, produces white clouds. The cal- 

 carious earth is precipitated, in its cauftic ftate, 

 by the union of the alkali with its vitriolic acid, 



on 



