Lakes and Springs on the Turko-Persian Frontier. 259 



The extreme saltness of this and the neighbouring lakes would 

 appear to arise from the separation, at some remote period, of 

 these masses of salt water from the main ocean, together with 

 the great Caspian and Aral lakes ; and the continued evaporation 

 by constantly diminishing their volume (as has been proved by 

 observations on the spot) has caused them ultimately to become, 

 as they are, perfectly saturated brines : and Mr. Loftus states 

 that there are others in the neighbourhood which have completely 

 dried up, leaving nothing but a great bed of salt. 



Sulphur Spring {Issi Su) between Dilman and Guverjin Kalah. 



This spring is situated to the north-west of the Lake of Uru- 

 mia ; " it rises from beneath a mass of blue limestone, which 

 emits a strong odour of sulphur. It deposits a considerable 

 efflorescence of carbonate of soda, generally pure white, but fre- 

 quently tinged with iron-yellow or red." 



This water, even when received into the laboratory, contained 

 a veiy considerable quantity of sulphuretted hydrogen, far more 

 than that of the Lake of Urumia, and even more than any of the 

 sulphuretted waters of Harrogate which I have examined ; there- 

 fore at the spot its fetor must have been extreme. 



Its specific gravity was 1'0142. On evaporation, a quantity 

 of total solid residue was obtained amounting to 981 "89 grains 

 in the imperial gallon, which contained lime, magnesia in small 

 quantity, and the alkalies ; iron, a trace ; also chlorine, sulphuric 

 and carbonic acids, and silica. 



I was enabled to determine the amount only of the following 

 constituents, and give the direct results of experiments in grains 

 in the gallon : — 



Lime 6"088 gi'ains. 



Chlorine 76-140 ... 



Sulphuric acid . . . 16-160 



Silica 7-181 ... 



From these it may be approximatively stated, that the following 

 are the saline constituents of a gallon of the water : — 



Sulphate of lime 14-78 grains. 



Sulphate of soda 13-24 ... 



Chloride of sodium 125-47 ... 



Carbonate of soda, with small quan-^ 



titles of the carbonates of lime > 827-22 



and magnesia, and a trace of iron J 

 Silica 1-18 ... 



Total saline constituents in the gallon 98 1 • 89 ... 



