15 



THE AVERAGE COMPOSITION OF ORDINARY FARM CROPS. 



The amount of food taken from the soil by different crops is given in 

 the following table, taken from " The Chemistry of the Farm," pp. 38, 39. 

 This table gives the average composition of ordinary farm crops as 

 grown in England; and the annual produce of beech, spruce, tir, and 

 Scotch pine forests, felled for timber, the results of extensive investi- 

 gations made in Bavaria. 



The quantities of carbon, hydrogen, and oxygen present are omitted ; 

 also some of the smaller ash constituents. By u pure ash " is meant the 

 ash minus sand, charcoal, and carbonic acid. 



TABLE I. The weight and average composition of ordinary crops in pounds, per acre. 



(R. irar'nujton.) 



