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ELISHA MITCHELL SCIENTIFIC SOCIETY. 65 



phosphate rock. The new mill at Raleigh was built to sup- 

 ply this demand, and the steady growth of the sales is an 

 indication of the esteem in which the product is held. 



An analysis of the article made at the Experiment Station 

 is as follows: 



Analysis of Ground North Carolina Phosphate Rock : 



' Bone Phosphate - - 1 1. 16 per cent. 

 Carbonate of Lime - - 64.26 per cent. 

 Magnesia - - - 0.81 per cent. 



Potash - - - - 0.40 per cent. 

 Water - - - . - 1.39 per cent. 



The fine ground rock offered by French Bros, is of a 

 somewhat higher grade. An analysis of their best grade is 

 as follows : 



' Phosphate of Lime - - 20.34 per cent 



Carbonate of Lime - - 



Lime as Oxide and Hydrate - 37-52 per cent 



Oxides oflron and aluminum, and loss 5.65 percent 



This analysis represents the composition of the residue 

 from burning and screening. 



The composition before burning and screening is as 

 follows : 



' Phosphate of Lime - - 16.42 per cent. 



Carbonate of Lime - - ' - 54.71 percent. 



Lime as oxide and hydrate 



Oxides oflron and Aluminum, and loss 3.91 percent. 



The burning and screening separates the phosphatic 

 nodules from the cement of carbonate of lime and converts 

 this last into lime oxide and hydrate. All three of these 

 articles are growing in favor with the farmers. The utiliza- 

 tion of raw ground rock in the preparation of home-made 

 manures, is one of the reasons why the price of acid phos- 

 phate and guano has declined. Extra inducements in the 

 shape of lower prices have now to be offered since the 

 farmer has discovered that he can buy a good article for 

 nearly 50 per cent, less than he has been accustomed to pay. 



^ Equivalent to Phosphoric acid 6.11 per cent. 

 2 Equivalent to Phosphoric acid 9.31 per cent. 

 '■^ Equivalent to Phosphoric acid 7.52 per cent. 



