Phosphatic Materials used for Agricultural Purposes. 19 



Composition of South American Bone- ash. 

 (Commercial Analysis.) 



The above were made in the manner usually adopted for 

 commercial analyses. It will be seen that, generally speaking, 

 samples poor in phosphate of lime are also poor in carbonate of 

 lime, lime not united with phosphoric acid, and alkaline salts ; 

 and the samples rich in phosphate of lime likewise contain a 

 higher percentage of the latter constituents. Thus, the sample 

 which contained 66*33 of bone-earth, yielded 7*13 of carbonate 

 of lime, &c. ; and the sample containing 64*70 of bone-earth, 

 yielded 7*63 of carbonate of lime, &c. ; whilst that which gave 

 70*45 of bone-earth yielded 10*72 of the latter constituents ; 

 and another sample in which 75*05 per cent, of bone-earth were 

 found yielded 12*02 of carbonate of lime, &c. 



Considerable allowance of course must be made for the natural 

 variations in the composition of the bones which produced the 

 ash. It is well known that some bones contain more carbonate 



C 2 



