424 



PRINCIPLES OF CHEMISTEY 



A saturated brine, formed by the continued contact of subsoil 

 water with rock salt, is extracted by means of bore- holes, as, for 

 instance, in the Governments of Perm, Kharkoff,. and Ekaterinoslav. 

 Sometimes, as at Berchtesgaden (and at Hallein) in Austria, spring 

 water is run on to underground beds of rock salt containing much clay. 



If a saline spring, or the salt water pumped from bore-holes, con- 

 tains but little salt, then the first concentration of the. natural solution 



FIG. 64. Graduator for the evaporation of the water of saline springs. 



is not carried on by the costly consumption of fuel, but by the cheaper 

 method of evaporation by means of the wind For this purpose 

 so-called graduators are constructed : they consist of long and lofty 

 sheds, which are sometimes several versts long, and generally extend 

 in a direction at right angles to that of the usual course of the wind in 

 the district. These sheds are open at the sides, and are filled with 

 brushwood as shown in fig, 64. Troughs, A B, c D, into which the salt 



the Government of Erivan in the Caucasus; (d) the-Katchiezmansky deposit in the 

 province of Kara ; (e) the Krasnovodsky deposit in the Trans-Caspian province ; and (/) 

 the Bardymkulsky saltmines inKokhand. 



