Rock Salt and Salines of the Holston. 1 79 



ire, where the brine is similar to this, the water is evaporated at 

 a temperature below ebullition, in shallow wrought iron pans of 

 an area of from eight to twenty square feet, which last for several 

 years. A pan of this description, brought over by the Hon. Wil- 

 liam C. Preston, was burnt out in a few months at Saltville. 

 The requisite low and uniform temperature could be readily 

 attained by the use either of steam or hot water, as a heating 

 agent, applied in the manner so frequently done in the manufac- 

 ture of sugar and similar departments of the arts. This modifi- 

 cation in the manufacture, besides avoiding the " blocking" and 

 improving the salt, would economize fuel, and the latter consid- 

 eration should urge itself with serious force upon the proprietors, 

 occupying as they do a region where forests must soon be ex- 

 hausted, and where geology forbids the hope of the discovery 

 of coal. 



A large proportion of the salt manufactured at Saltville, is 

 made by the process of direct evaporation, already described. A 

 whiter and purer salt is made by first concentrating the brine in 

 a wooden cistern, through which steam is conducted in a cast 

 iron pipe, which sufficiently concentrates the brine to produce 

 a deposition of most of the sulphate of lime ; the concentrated 

 brine is then conveyed to the kettles, and evaporated as in the 

 other process. The salt thus manufactured is purer, more dis- 

 tinctly crystalline, and has a white satin lustre. The following 

 analysis of the two varieties of salt, will show the difference in 

 their composition. No. 1, is the salt made by the process last 

 described ; No. 2, by the first process, of rapid evaporation. 



No. 1. No. 2. 



Sulphate of lime, 1.444 1.820 



Chloride of calcium, .016 .034 



" of sodium, 98.540 98.146 



The two establishments at Saltville manufacture annually two 

 hundred thousand bushels of salt. 



Abingdon, Va., Nov. 30th, 1842. 



