(502 



MA N UFACTURES. 



j)hosphoric acid it contains as food. Measurements Avitli the micrometer 

 show that the size of the particles obtained by grinding vary from the 

 (1,003 inch to the 0,00003 inch. By chemical tests it was estimated that 

 as much as twenty-five per cent, of the phosphoric acid present in this 

 (hist was dissolved by the ammonium citrate solution used in laborato- 

 ries to represent the soil water, plant-root juices and other solvents in the 

 f'oW ; from which it was inferred that this jDcrcentage was available by 

 ]>lants. The best results were obtained from the finest powder, that is, 

 Avhere eighty-five per cent, of the particles were finer than 0,0003 inch. 

 Improvements in machinery to reduce the phosphate rock to an impalpa- 

 ble powder are being much sought, since the great expense necessitated 

 by chemical processes in rendering it soluble would be avoided if this 

 could be accomplished by mechanical means. Analysis shows that the 

 [icrcentage of phosphoric acid in "floats" varies from 24.2 to 27.8. The 

 following table shows the average of the analysis of fertilizers manufac- 

 tured in South Carolina, being tlie mean of ana]3^sis made for the De- 

 partment of Agriculture of South and of North Carolina, together with 

 tlie estimated value per ton of 2,000 pounds, based on the current prices 

 of the phosphoric acid, ammonia, and potash they contain. 



o 



Simple Superpliosphates 



Simple Superphosphates, with Potash . . . 

 Ammoniated Su2:)erp'phates, without Potash. 

 Ammoniated Superpliosphates, with Potash. 



11.77 



10.55 

 9.61 

 8.95 



2.96 

 2.70 



$28.57 

 1.29| $26.66 

 . . $38.41 

 1.73| $35.18 



The product of these factories exceeds 110,000 tons yearly, the average 

 estimated value of the product at the factory is placed at $20 per ton. 

 By the Tenth U. S. Census, South Carolina stood fifth among the States 

 in the manufacture of manures. The product for the State was estimated 

 at that date at 64,794 tons, and it is prol)able that the increase in the 



