-50 rETTEIlSSON, ON U-ATEH AXV ICE. 



current of the great rivers of Siberia. But it will sooii be 

 found, tliat all these kinds of water are not of equal impor- 

 tance. Tlie peculiar conformation of the Siberian sea seems 

 to depend upon two main components, viz. tlie salt water from 

 the ocean, which on account of its specific gravity sinks to 

 the bottom and is found, wherever the depth of the sea exceeds 

 20 or 30 metres, and the fresh or brackish water from the 

 estuaries of the rivers, which predominates at the surface and 

 also extends to the bottom of the shallow parts of the sea 

 along the coast. On the plates of the followiug paper, where 

 the curves of equal saltness and temperature are traced, we 

 will everywhere find layers of little or no saltness superposed 

 upon, and in contact with real oceanwater, the intermediate 

 layers either thinning out or vanishing altogether. The 14"" 

 of August 1878, iii the northeastern part of the Kära Sea, at 

 76° 18' Lat. and 95° 30' Long. E. G., a serial deepsounding was 

 taken, the density and temperature of the water being deter- 

 mined for every ö**" metre from the surface to the bottom. 

 The result is shown in the following table: 



Thus the samples of water collected by the Vega-expedi- 

 tion present the most striking examples of abrupt changes in 

 saltness and temperature, proving that the intermingling of 

 the fresh and salt water had just begun at that distance from 

 the cöast, where the Vega passed. 



It is not very probable, that the Siberian sea ever attains 

 a uniform and homogeneous composition, not even at higher 

 latitudes. The difference in the temperature of the salt and 



