No. 6. DEPARTMENT OF AGRICULTURE. 883 



111 the case of refuse bone-black, uuacidulated, the moan, 28.2") 

 per cent, of phosplioric acid, is assumed to represent tlie average 

 matciial on the market. 



Phosphate rock is sold by the ton of 2,240 lbs., and on the basis 

 of the bone phosi)hate of lirae it contains, with drawbacks for in- 

 jurious constituents. Bone-phosphate of lime contains 45.8 per 

 cent, of phosphoric acid; therefore, each per cent, of bone phosphate 

 in a long ton is equivalent to 22.4 lbs. and contains 10.26 lbs. of 

 phos])horic acid. 



In the wholesale trade, dried blood, azotine, concentrated tankage 

 and hoof meals are usually sold on the basis of ammonia, disre- 

 garding the phosphoric acid jjresent. 



Insoluble phosphoric acid in dissolved rock is likewise omitte^ 

 from consideration, contracts being based solely upon the ''avail- 

 able" phosphoric acid; nor in rock phosphates is any claim made 

 for the small quantities' of nitrogen and potash they contain, nor 

 in dissolved bone for the potash present. 



Under these conditions, the wholesale cost per pound in New 

 York of the valuable constitutents of such materials as furnish but 

 a single fertilizing element, these materials being assumed to be 

 in the state of preparation and in the packing in which the manu- 

 facturer purchased them, are given in the following table; also, a 

 figure representing a fair retail x>rice at the factory, the materials 

 having undergone no change in treatment or packing and the allow- 

 ance for expense and profit in retailing being 20 per cent.: 



