Scientific Intelligence— Hydrography, 37t 



HYDROGRAPHY. 



6. M. Chancourtois, on the Salt Lake of Van^ in Armenistan. — 

 On the 17th November 1845, M. Dufrenoy read to the Academy 

 of Sciences of Paris, the following notice, by M. de Chancourtois, 

 Engineer of Mines, on the Nature of the Water of the Lake of Van, 

 and of the Natron obtained from it : The Lake of Van is situated 

 in Southern Armenistan, near the frontiers of Persia, between the 

 38th and 39th degrees of latitude. Its superficies maybe calcu- 

 lated at about 2000 square kilometres. It was determined by me, 

 barometrically, to be about 3600 English feet (1100 metres) above 

 the level of the sea. It is enclosed to the south by the first chain 

 of the mountains of Kurdistan ; to the west, by Mount Nemrod, an 

 extinct volcano ; and to the north, by Mount Seupan, whose conical 

 summit is covered by perpetual snow ; to the east the mountains 

 are cut by large valleys, and it is from that side that the principal 

 supplies of water arrive. It does not present any means of exit for 

 its waters, and its level frequently rises or falls for many years 

 in succession, independently of the periodical variations consequent 

 on the seasons. After the melting of the snow, the fishes of the 

 rivers advance to a certain distance into this small sea ; but at every 

 other time the waters of the lake are completely deserted. It was 

 this circumstance, of which I was informed by the inhabitants of the 

 villages on its shores, which first attracted my attention. I sub- 

 mitted to separate analysis, on the one hand, the water of the 

 lake, and on the other, the salt which is obtained by the inhabitants 

 by means of evaporation in small basins. The density of the water 

 was found to be 1-0188, at the temperature of 67° Fahr. (19°.5). 

 Its composition is the following: — 



Chloride of sodium, . . 0'938 

 Sulphate of soda, . . 0*333 

 Sulphate of potash, . . 0*055 



Sesouicarbonateofsoda, . 0-861 } --StL*^?e[" °' 

 Sesquicarbonate of magnesia, 0*055 

 Silica, .... 0*018 



Oxide of Iron, . . .a trace 

 Water, .... 97*740 



100-000 



The salt, such as is sold at the bazaar, presents crystalline crusts, 

 which are thin, very friable, superimposed on one another to a 

 thickness of about 2 inches (5 or 6 centimetres), and for the most 

 part rendered impure by the earth of the basins. Small cubical 

 crystals of rock-salt are almost always to be seen imbedded in the 

 amorphous layers of the other salts. The mass attracts the hu- 

 midity of the air, but without becoming in any degree deliquescent. 

 The composition of the salt is the following : — 



VOL. XL. NO. LXXX.— APRIL 1846. 2 B 



