180 Report of the Acting Director and Chemist of the 



amount to only 20 or 30 per cent, and what is the remaining portion, 

 amounting to TO or 80 per cent, made up of ? " A few ilhistrations 

 will, perhaps, suffice to make the matter clear. 



High-Grade Fertilizers. — Taking a fairly high-grade fertilizer, 

 we find by analysis that it contains : 



Nitrogen 4 per cent. 



Available phosphoric acid 8 " 



Insoluble " " 2 " 



Potash 10 " 



If the nitrogen comes from dried blood or meat, it will take about 

 10 pounds of such material to furnish 1 pound of nitrogen. Since 

 there are 4 per cent, of nitrogen, or 4 pounds of nitrogen in 100 

 pounds of fertilizer, it will take 40 pounds of dried blood to furnish 

 this amount of nitrogen. The amount of bone and sulphuric acid 

 necessary to make a phosphate containing 8 pounds of available 

 phosphoric acid and 2 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 4 pounds of nitrogen 40 



Bone and sulphuric acid required to furnish phosphates containing 8 



pounds of available and 2 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 : 



Niirogen 1 per cent. 



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 



