152 AMERICAN MANURES. 



make an article much inferior to the above, by 

 using an insufficient amount of sulphuric acid, 

 and as much water as possible. 



For the sake of illustration, we will show the 

 value of a superphosphate of the following com- 

 position, which is a better one than is usually fur- 

 nished by manufacturers, as a comparison of the 

 analysis we give of it, with that of the analyses 

 of celebrated manures given in Chap. VII., will 

 show. 



1512 Ibs. Mineral Phosphate, at $10 per ton $ 7.31 



250 " Sulphuric Acid, at 2J cents per Ib 6.25 



300 " Water 



2062 " 



Grinding, Labor, Bags, etc 8.50 



62 " Loss in Gas. 



Total cost $22.06 



2000 " 



This attempt at making a superphosphate 

 would, on analysis, show very nearly the follow- 

 ing composition : 



Soluble Phosphoric Acid 6 '32 per cent. 



Equal to Superphosphate of Lime 10*41 " " 



Insoluble Phosphoric Acid 10-97 " " 



Equal to Bone Phosphate 24'00 " " 



A ton of this contains 346 Ibs. of phosphoric 

 acid, 126 i Ibs. of which is soluble and 219 i Ibs. 

 insoluble ; and the value of a ton to the farmer 

 would be as follows : 



