15« 



A TREATISE ON THE CONNECTION OF 



■ed, and the vitriolic acid of the gypsum will join with the 

 •mineral alkali, forming Glauber salt, which is very soluble. 

 The quantity of gypsum previously existing in the soil is 

 to be ascertained by weighing, when properly dried, the 

 -cal^reous matter which had been precipitated by the al- 

 kali ; and by adding thereto, in calculation, the propor- 

 tion of vitriolic acid necessary to constitute it gypsum ; 

 having previously dedufled therefrom the proportion of 

 fixable air which the precipitated chalk contains. The 

 proportion of fixable air and vitriolic acid contained in 

 chalk and in gypsum are in the proportions as here 

 stated : 



The following is given as an example of the method 

 of making this calculation : 



Residuum 



