AGRICULTURE WITH CHEMISTRY. 69 



magnesia : in which case, on the decomposition of the 

 schyst, or pyrites, the vitriolic acid so formed, will, by 

 superior affinity, join with the magnesia, and form Epsom 

 salt, in preference to the argillaceous or ferruginous, 

 matter of the above-mentioned substances. 



Epsom salt is very soluble, dissolving in about twice its 

 weight of cold water. It is decomposed by lime and 

 alkalis, forming therewith gypsum, vitriolated tartar, 

 Glauber salt, or vitriolic ammoniac. By Dr. HOME'S 

 experiments, Epsom salt has been found in a very high 

 degree to promote vegetation* He states, that it made the 

 garden mould he used for his experiments produce one 

 fourth more grain. 



SULPHAT 



