Fertilizers and Fertility. 347 



Or there will be as many hundred pounds of dried blood needed 

 as 12 is contained in 40: 



2,i X 100 = 333. 



In a similar way the amount of acid phosphate is found that will 

 yield 160 pounds of phosphoric acid. 



One hundred pounds acid phosphate equal 14 pounds phosphoric 

 acid, 



160 X ICMD 



100 : 14 : : X : 160 == 1,143 pounds. 



14 



If muriate of potash supplies the potash, then the amount neces- 

 sary to yield 80 pounds potash is found in exactly the same way: 

 One hundred pounds muriate of potash equal 50 pounds potash. 



100 X 80 



100 : 50 : : X : 80 =^ 160 pounds. 



50 

 Hence, if one mixes 



333 pounds dried blood 

 1,143 pounds acid phosphate 

 160 pounds muriate of potash 



1,636 total, 



there is used enough of each to yield a ton of fertilizer that will contain 

 2 per cent, nitrogen, 8 per cent, phosphoric acid and 4 per cent, potash. 

 But immediately it is seen that the amounts used do not make a ton 

 of 2,000 pounds. The total weight lacks 364 pounds of being a ton. 

 (2,000—1,636=364.) 



This difference is supplied by mixing in some material as a filler; 

 often it has no fertilizing value ; sometimes substances are used that have 

 an indirect value, as land plaster. The lower the percentages of the 

 different fertilizing constituents in a fertilizer, the greater is the amount 

 of the filler used. 



When these different materials are mixed, they do not act on each 

 other in any way, nor is there any special technical knowledge needed 

 in order to mix them. After learning the amounts of each it may be 

 desired to be mixed, the remainder of the operation is nearly as easy 

 as mixing corn and oats. It sometimes happens that some of the materials 

 get damp and lump up or even cake into more or less solid masses, and 

 to pulverize them may take a little time ; but, aside from mechanical 



