Chemical Analyses of Fertilizers 177 



alone it is as good as the other ; but it has been already 

 shown that the value of a fertilizer depends not only upon 

 the total content of its constituents, but upon the form 

 in which they exist. In the first brand it is found that two- 

 thirds of the total nitrogen exists in the soluble form, 

 equally divided between nitrate and ammonia; the re- 

 maining third is in the organic form, and may be derived 

 from blood, or from some low-grade materials. It is to be 

 fairly presumed, however, that when thus associated with 

 so high a proportion of soluble nitrogen, it is in a good 

 form, as the manufacturer has given evidence of his intent 

 by his liberal use of other good forms. 



In the case of the phosphoric acid, it is shown that 

 of every 100 pounds of the total, 80 pounds are soluble, 

 10 reverted, or nine-tenths of the whole is available ; 10 

 pounds of every hundred only are insoluble, which is not 

 only an indication, but positive proof, that the phosphoric 

 acid is derived from a superphosphate. 



In the case of potash, the chlorin associated with it 

 is but J per cent, indicating that it has been drawn from 

 high-grade sulfate, since kainit and muriate are rich in 

 chlorin, while in a high-grade sulfate no appreciable 

 amounts of chlorin are present. 



In the second statement, all of the nitrogen is shown 

 to be in the form of organic matter. It may be derived 

 from blood, though it is not likely to have been drawn 

 from this source, since of the total phosphoric acid but 

 20 pounds to the hundred, or one-fifth, is available, and 

 that is reverted rather than soluble, indicating that the 

 phosphoric acid must have been drawn from tankage or 

 from bone, or other materials which contain reverted but 

 no soluble phosphoric acid, and which also contain a con- 

 siderable percentage of nitrogen. The phosphoric acid 



