The Composition and Use of Fertilizers. 807 



pounds of available phosphoric acid and two pounds of insoluble 

 phosphoric acid would amount to about 40 pounds. If the potash 

 is present in form of high-grade sulphate, about 20 pounds of 

 such sulphate would be required to be equivalent to 10 pounds of 

 potash. Tabulating the foregoing figures, we have the following: 



Pounds. 



Dried blood required to furnish four pounds of nitrogen, 40 



Bone and sulphuric acid required to furnish phosphates 

 containing eight pounds of available and two pounds 



of insoluble phosphoric acid 40 



Sulphate of potash equivalent to 10 pounds of potash. . . 20 



Total 100 



In a fertilizer of this character, we can easily account for the 

 entire amount of material. 



Low-Grade Fertilizers. — Taking now a low-grade fertilizer, 

 we find its composition to show: 



Per cent 



Nitrogen 1 



Available phosphoric acid 5 



Insoluble 1 



Potash 1 



We will suppose that the nitrogen and phosphoric acid come 

 from the sources as indicated above and that the potash comes 

 from kainit, eight pounds of kainit containing one pound of pot- 

 ash. Then we can tabulate our statement as follows: 



Pounds. 



Dried blood required to furnish one pound of nitrogen, 10 

 Bones, etc., required to furnish five pounds of available 



and one pound insoluble phosphoric acid 24 



Kainit equivalent to one pound of potash 8 



Moisture, land plaster, dried earth, ground rock, etc. . . 58 



Total 100 



