ABICH ON THE NATRON LAKES OF THE ARAXES. 2/ 



periods of volcanic activity in this district, has bnrst forth from a Hne 

 of distinctly marked eruption-cones of considerable size at the north- 

 west foot of the Greater Ararat, which seem as it were to push the 

 declivities of the mountain forward into the plain. The extent of 

 the lake is such, that the water-fowl frequenting it are, when in the 

 middle, beyond gun-shot from any side. It contains a weak solution 

 of common salt along with that mixture of Glauber-salt and carbonate 

 of soda, which effloresces from the marly clays, that form the soil of 

 the plain, wherever artificial irrigation has not been introduced, and 

 a more or less vigorous vegetation of Graminese, heaths and soda- 

 plants, been established. 



In the warmest season of the year the water of the shallow lake 

 retires three or four feet from its usual banks ; on which a crust of 

 salt a few feet broad and about half an inch thick is then deposited. 

 It forms an irregular crystalline mass of porous cubes of common 

 salt, the lamellae and spaces between which are filled with the saline 

 mixture just mentioned. It has in general a pale rose-red colour. 



The water taken from the lake in the end of October contained in 

 100 parts 93'34 water and 6*66 solid anhydrous salt. Analysis 

 showed the latter to consist of — 



Sulphate of soda (Na S) 10-36 



Carbonate of soda (Na C) 14*71 



Chloride of sodium (Na Cl2) 74-61 



Hence 100 parts of the fluid contain only 2-63 per cent. Na S -|- 



10 H and 1-78 per cent. Na C -H 10 H. 



The composition of the salt-crust deposited in the warm season I 

 found to be — 



Carbonate of soda (Na C) 22-91 



Sulphate of soda (Na S) 16*05 



Chloride of sodium (Na C12) 51-49 



Water 9*88 



Magnesia traces. 



By dissolving and recrystallizing I obtained natron mixed with 

 Glauber-salt, which by repeated crystallization formed fine crystals. 



Other lakes, very remarkable both for their geological relations and 

 the salt they contain, lie to the south-east of the Little Ararat. On 

 this side, and exactly in the direction of the longer axis of the system 

 of Ararat, the Little Ararat has at one time opened about half-way 

 up in a fissure and spread out over its gentle declivities towards the 

 plain of the Araxes, that gigantic flood of dolerite, which pushes far 

 down into the basin of Nachitschevan. Its principal branch follows 

 a valley that opens in a south-eastern direction, on the right side of 

 the Araxes, between a rocky chain of hills named Giisgiindag (i. e. 

 Hill of the SurCs eye, because it lies to the south), and a group of 

 mountains which surround in a large semicircle the Little Ararat on 

 the south and south-west, until it disappears entirely below the 

 colossal lava-covering of the Carnijarach, the greatest of all the 

 secondary eruption-cones of the Ararat system. 



