76 AMERICAN MANURES. 



application for the destruction of vermin is in 

 the fact that, if the solution be strong enough to 

 effect the object, it may destroy the vegetation 

 also. 



If there is sufficient salt in the soil to supply 

 soda and chlorine to the plant, it is not advisable 

 to add more for any physical effect it may pro- 

 duce in the decomposition of organic substances ; 

 and generally, as an excess is very injurious, it 

 should in all cases be applied with great caution. 

 As an example of the small amount generally 

 required, we may state that a crop of 25- bushels 

 of wheat, together with the straw, contains only 

 a little more than 5 Ibs. of soda, and 2 J Ibs. of 

 chlorine, which 10 Ibs. of common salt will fur- 

 nish. 



If soda alone, and not chlorine is needed, it 

 can be cheaply supplied in the form of sulphate 

 of soda or salt cake, which is a by-product in the 

 manufacture of hydrochloric acid, and in which 

 the chlorine of the salt is replaced by sulphuric 

 acid. 



