BONE MANURE. 1 5,5 



creasing the fertility of a soil. Now, when this acid is sprinkled 

 on calcareous soils, gypsum (sulphate of lime) is immediately 

 formed, which, of course, prevents the necessity of manuring the 

 ground with this material. 100 parts of concentrated sulphuric 

 acid diluted with from 800 to 1000 parts of water, are equiva- 

 lent to 176 parts of gypsum. 



Many kinds of ashes, of peat, and most varieties of coal 

 ashes, contain an abundant quantity of gypsum, by which they 

 exercise a very favorable influence on certain soils. 



