LOFTUS TURKO-PERSIAN FRONTIER. 307 



According to Prof. Hitchcock, the specific gravity of the water of 

 Uriimia Lake is ri55, and his analysis of 500 grains gave 102*1 of 

 salts, or more than one-fifth of the whole. The water of the ocean 

 only yields one-thirtieth of its weight in salts. 



At Giiverjin Kalah the temperature of the water on the 14th 

 August 1852, at 11^45™ a.m., was 78° Fahr., which is high ; possibly 

 on account of the proximity of the limestone rocks. 



I carefully examined the surface of the rocks at the water's edge, 

 but could detect no indications of the Lake having ever been higher 

 than at present. The natives say, that they remember no change of 

 level, beyond a slight annual rise and fall attendant on the melting 

 of the snows. This does not agree with the account of Mr. Perkins, 

 who, from many years' careful observation, says, that the Lake of 

 Uriimia is rapidly diminishing in extent ; — that the small dykes 

 which existed eighteen years ago for the purpose of restraining the 

 water in shallow troughs, where salt was collected, and were then 

 close upon the^ edge of the Lake, are now fully half a mile distant 

 from the present margin. Salt is collected along the shores in large 

 quantities, and conveyed into Turkey. On crossing the Frontier a 

 tax of ten paras (rather more than a halfpenny) per load is exacted ; 

 the value of a load in Turkey being about 1*. 3d. It would be 

 interesting to ascertain whether the saltness of the water is increasing 

 or diminishing. 



Some authors have endeavoured to account for the excessive salt- 

 ness of the Lake by supposing that it is attributable to the streams 

 which flow into it from salt rocks on the north and east. This 

 theory, however, cannot be maintained ; because such streams are 

 comparatively few and insignificant, and their effect would be neu- 

 tralized by the large number of pure streams, some of considerable 

 size, which flow from other quarters, especially those rising in the 

 lofty Frontier-chain on the west. 



My own idea on the subject is based upon the examination of the 

 neighbouring igneous chain, which, it is evident, has been elevated 

 at a very recent period. During this elevation, it is by no means 

 diflficult to conceive that large isolated bodies of salt water were 

 detached from the then existing main ocean, and settled in basins, 

 such as the Caspian and Aral Seas, and the Lakes of Uriimia and 

 Van. Supposing that, after detachment, a rapid evaporation took 

 place from great heat caused by igneous action at the bottom of 

 these basins, the water would of course become more salt, and under 

 certain circumstances rock-salt would be deposited. (See also p. 309.) 

 Continual evaporation w^ould tend to increase the saltness ; and, if the 

 freshwater streams flowing in did not equal the quantity of water so 

 dissipated, a continually increasing saltness would take place, while 

 the sea or lake would be gradually decreasing its limits. Such I 

 believe to have been the origin and cause of the excessive saltness of 

 the Lake of Uriimia. In corroboration of this theory, we have not 

 only porphyritic and granitic eruptions on its shores, but consider- 

 able deposits of rock-salt in the neighbouring Plain of Khoi, which 

 are described in the following Section. 



y2 



