h expedition in 1904 found no traces of organic
life below the depth of 220 fathoms except micro-organisms and a single
Oligochaete; but above that level there exist abundant evidences of rich
pelagic life, more particularly from the surface down to a depth of 80
fathoms.

_Fisheries_.--No other inland sea is so richly stocked with fish as the
Caspian, especially off the mouths of the large rivers, the Volga, Ural,
Terek and Kura. The fish of greatest economic value are sturgeon (four
species), which yield great quantities of caviare and isinglass, the
herring, the salmon and the lobster. The annual catch of the entire sea
is valued at an average of one million sterling. Some 50,000 persons are
engaged in this industry off the mouth of the Volga alone. Seals are
hunted in Krasnovodsk Bay.

_Salinity_.--The proportion of salt in the water of the Caspian, though
varying in different parts and at different seasons, is generally much
less than the proportion in oceanic water, and even less than the
proportion in the water of the Black Sea. In fact the salinity of the
Caspian is only three-eights of that of the ocean. In the northern
section, which receives the copious volumes brought down by the Volga,
Ural and Terek, the salinity is so slight (only 0.0075% in the surface
layers) that the water is quite drinkable, its specific gravity being
not higher than 1.0016. In the middle section the salinity of the
surface layers increases to 0.015%, though it is of course greater along
the shores. The concentration of the saline ingredients proceeds with
the greatest degree of intensity in the large bays on the east side of
the sea, and more especially in that of Kara-boghaz, where it reaches
16.3% (Spindler expedition). The bottom of this almost isolated basin is
covered for an area of 1300 sq. m. with a deposit of Epsom salts
(sulphate of magnesia), 7 ft. thick, amounting to an estimated total of
1,000,000,000 tons. While the proportion of common salt to sulphate of
magnesia is as 11 to 1 in the water of the Black Sea and as 2 to 1 in
the Caspian water generally, it is as 12.8 to 5.03 in the Kara-boghaz.
The salinity of the surface water of the southern section of the Caspian
averages 1.5%.

_Climate_.--The temperature of the air over the Caspian basin is
remarkable for its wide range both geographically and seasonally. The
January isotherm of 15 deg. F. skirts its northern shore; that of 40
deg. crosses its southern border. Bu