66 A TREATISE ON THE CONNECTION OF 



alkaline salts. The neutral salts formed by such applica- 

 tions will be gypsum, Epsom $alt, sulphat of potash, sul- 

 phat of soda, and sulphat of ammoniac, according to the 

 species of alkali applied. Although no beneficial cfFedts 

 were found to result from the experiments made by Dr. 

 Home, yet they may with great probability be expected 

 to arise by the application of allum to soils con- 

 taining much calcareous matter ; especially to such as 

 contain, beside this latter substance, a sufficient pro- 

 portion of animal and vegetable matter. The allum will 

 in this case be decomposed by the calcareous matter, on 

 the principle of superior affinity, whilst the fixable air of 

 the calcareous matter will be disengaged, and on being 

 absorbed by the roots of plants, will afford them the car- 

 bonaceous principle. 



SULPHAT 



