No. 6. DEPARTMENT OF AGRICULTURE. 7L'7 



•tituents cau be readily estimated. In the case of amuiouiates, tlie 

 quotatious are "per unit of amuiouia" iii mauy cases. The term 

 ''unit" is equivalent to "per ceut.;" iu goods sold by the tou of 2,000 

 lbs., the unit is equal to -0 lb«.; and 20 lbs of ammonia contains 10.47 

 lbs. of nitrogen. 



In the case of refuse bone-black, unacidulated, the mean, 28.25 per 

 cent, of phosphoric acid, is assumed to represent the average ma- 

 terial on the market. 



Phosphate rock is sold by the ton of 2,240 lbs.; this material is sold 

 on the basis of the bone-phosphate of lime it contains, with draw- 

 backs for injurious constituents. Since the bone phosphate of lime 

 contains 45.8 per cent, of phosphoric acid, each per cent, of bone 

 phosphate in a long tou of phosphate rock is equivalent to 22.4 lbs. 

 and contains 10.20 lbs. of phosphoric acid. 



In the wholesale trr.de, it is customary to sell dried blood, azotine, 

 horn and hoof meals, and concentrated tankage solely on the basis 

 of ammonia, to the entire disregard of the phoisphoric acid contained. 



Likewise, the insoluble phosphoric acid in dissolved rock is omitted 

 from consideration, and contracts are based solely upon the "avail- 

 able" phosphoric acid; that is, the sum of the "soluble" and "revert- 

 ed" or "citrate soluble" phosphoric acid; nor in rock phosphates ia 

 any claim made for the small quantities of nitrogen and potash they 

 always contain, nor in dissolved bone for the potash present. 



Under these conditions, the wholesale cost per pound in New York 

 of the valuable constituents of such n-aterials as furnish but a single 

 fertilizing element, these materials being assumed to be in the state 

 of preparation and in the package in which the manufacturer pur- 

 chased them, are given in the following table; also, a figure repre- 

 senting a fair retail jirlce at the factory, the materials having under- 

 gone no change in treatment or packing, and the allowance for ex- 

 pense and profit in retailing being 20 per cent. 



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