216 CHEMISTRY. 



the suffocating chlorine, which would take place here and 

 there, would produce the most disastrous results. 



298. Localities of Salt. While salt is so widely diffused, 

 there are some localities where it is found in great abund- 

 ance. There are extensive beds of it in Spain, in some cases 

 rising in hills three or four hundred feet high. The same is 

 true of the north part of Africa. Then there are extensive 

 beds in various parts of the continent of Europe, in Cheshire, 

 England, in Persia, China, India, and South America. The 

 most remarkable salt-mines are in Prussia, Poland, and Hun- 

 gary. Some deposits have been found in this country, in 

 Virginia and Louisiana. There are extensive salt lakes in 

 Africa and South America. In this country there is the 

 famous Great Salt Lake, on a height among the Rocky 

 Mountains, 4200 feet above the level of the sea. There are 

 in this country some salt springs which are very productive. 

 The most celebrated are those at Salina and Syracuse, the 

 latter producing annually five millions of bushels of salt. 



299. Modes of Obtaining Salt. The rock-salt is sometimes 

 nearly pure, as at Norwich, in Cheshire, England, where 

 large masses from five to eight feet in diameter are found, 

 and it is prepared for use by crushing between rollers. 

 Commonly, however, it is impure, and to purify it the salt 

 is dissolved in water; and when the impurities have settled, 

 the solution is drawn off and evaporated, that the solid salt 

 may be obtained. In this country the salt is gathered by 

 evaporating the brine which is flowing continually in. For 

 this purpose wells are made from 50 to 150 feet deep, and 

 the brine, as it is pumped up, is conducted by troughs to 

 large boilers. Sometimes the evaporation is left to occur 

 without the application of heat, by exposing the brine to 

 the sun in large shallow vats. This process is often made 

 use of in hot climates for obtaining salt from sea-water. A 

 number of extensive shallow basins having a smooth bot- 



