VALUATION OF PHOSPHORIC ACID. 137 



prices asked for, the best commercial superphos- 

 phates, might do for England and Saxony, where 

 manufacturers have done all they can to improve 

 and perfect manures and superphosphates, and 

 make as good an article as possible for the money. 

 But to take such a standard to estimate the value 

 of general American superphosphates, where an 

 entirely different state of things prevails, would 

 be simply ridiculous ; hence, we shall proceed to 

 estimate from a different basis. 



At the present time the valuable materials 

 used in the manufacture of commercial manures 

 and superphosphate of lime, are Bones, Mineral 

 Guanos or Phosphorite, Peruvian Guano, Crude 

 Sulphate of Ammonia, Muriate and Sulphate of 

 Potash. 



There are only three substances that serve as 

 a basis for fixing the value of commercial man- 

 ures. These are Phosphoric Acid, Ammonia 

 and Potash. Most of the other substances used, 

 such as Salt Cake, Gypsum, etc., are a source 

 of actual loss to the former, because he has to 

 pay 2i cents or more per Ib. for them when 

 mixed with superphosphate of lime; whereas, 

 if he needs them, he can buy them unmixed for 

 I of a cent per Ib. : hence, every pound of them 

 in the superphosphate, involves a loss of at 

 least li cent. They are added by the manu- 

 facturer only to give bulk and increase his 



