and the formation of Gypsum and Magnesian Rocks. 179 
obtained. It did not effervesce with hydrochloric acid, and was 
; The saline liquid by evap- | 
nesia, 
ings, and t D : 
_ when treated with hhydndohioes acid, left crystalline grains of 
gypsum. 
_ 26. In the foregoing experiments it is not easy to separate the 
“ae with the alkaline filtrate in which we wish to determine 
this salt. As a solution of magnesian carbonate which has lost 
__ its excess of carbonic acid by evaporation is incompatible with — 
ta 
su 
