SOUTH CAEOLINA PHOSPHATES. 105 



river-bed, and depositing on the next boat, about a cubic 

 yard of material at each dip, one-half of which will be mud, 

 sand and clay and the other half rock, usually in small frag- 

 ments, sometimes in slabs three or four feet in length. The 

 third boat carries another steam-engine, to operate a force- 

 pump for washing. There are two hoppers, into which 

 alternately are deposited dredge-loads of the material, and 

 into which is directed a large stream of water from the pumps, 

 with a constant pressure of seventy pounds of steam. Thus 

 the rock is rapidly worked clean, and by the operation of a 

 brake is deposited ready for market in the next boat, as fast 

 as two men can shovel it away. This establishment will raise 

 and prepare for market from seventy-five to one hundred tons 

 in ten hours, employing about fifteen hands. The rock, at 

 the wharf, sells for seven dollars per ton, or six dollars, less 

 the royalty. It does not take a very sharp Yankee to figure 

 out a profit in this business. The company have in operation 

 another like establishment in the same vicinity. They hf^ve 

 also, on the Bull River, about forty miles from Charleston, 

 immense machinery capable of raising several hundred tons a 

 day. The rock under this river is continuous, or in an 

 unbroken layer, and has to be separated or crushed before 

 washing. 



For manufacturing, the rock is first ground into what may 

 be called bone-meal, whence, by the use of sulphuric acid 

 and the addition of ammonia, is prepared a most excellent 

 fertilizer. 



The great market for the crude rock is in England, where, 

 by the use of a somewhat similar substance, found in the Lon- 

 don basin, they have learned its value. The consumption, 

 North and South, is rapidly increasing, so it would seem there 

 can be no lack of demand in the market. Thus has Charles- 

 ton, from being an importer, suddenly become one of the 

 greatest exporters of fertilizers in the world, and great must 

 be its influence on the commerce and prosperity of that city 

 and State. 



14 



