226 



THE CULTURE OF FARM CROPS. 



But it is still more soluble than the simple natural phos- 

 phate and is therefore more available as plant food. 



This process of manufacture is carried on upon a large 

 scale, and a large number of factories are now in operation 

 making superphosphate, either from raw bones, boiled bones, 

 or bone charcoal; and from the mineral phosphates. There 

 is no difference in the result from any one of these mater- 

 ials so far as the phosphoric acid is concerned, this is the 

 same in all; but the raw bone contains a large quantity of 

 organic matter containing nitrogen, hence the superphos- 

 phate made from this kind of bone has more value than the 

 other kinds. The extent of the manufacture of this class 

 of fertilizers may be realized from the fact that more than 

 400 different brands of it were analyzed by the Pennsyl- 

 vania Agricultural department in 1883. 



From the wide field thus open to the nefarious purpose 

 of dishonest persons, the manufacture of this class of ferti- 

 lizers is placed under the purview and control of the va- 

 rious State governments and stringent laws have been enacted 

 to secure honest dealings on the part of the makers of these 

 fertilizers. That this is necessary, and that it is also nec- 

 essary for farmers to look closely to their own interests in 

 this respect, the following analyses of various brands of 

 superphosphates is a very clear proof. 



Superphosphates from , ^1 



Claimed. 



Bone black 18.00 



17.00 



" 17.00 



18.00 



17.00 



Bones 31.00 



" 18.00 



S. Carolina Rock 13.00 



12.00 



13.00 



12.00 



15.00 



12.00 



. 12.00 



