942 



SCIENCE. 



[N. S. Vol. VIII. No. 209. 



tofore assumed. Wo may admit that this 

 great depth, as well as that of nearly 2,000 

 fathoms betweea Bering Island and the 

 Aleutian Islands, to some extent facilitates 

 the ingress of the waters of the Pacific, but 

 in the matter of transfer of salt from one 

 sea to another an ample supply of this sub- 

 stance is more essential than great depth of 

 connecting channel. The Strait of Gibral- 

 tar, which, as we have seen elsewhere, reg- 

 ulates the density of not only the Mediter- 

 ranean, but also of a large part of the 

 Atlantic, has the moderate depth of 170 

 fathoms. 



The temperature curve shows a minimum 

 of 37°. 5 in 100 fathoms; this indicates that 

 the heat which is transmitted from the sur- 

 face does not descend below that limit and 

 that whatever heat we find at greater depths 

 has been conveyed by the same undercurrent 

 which carried the salt. There is consider- 

 able difference in the bottom temperatures 

 of the great depths; they vary from 34° to 

 35° and are perhaps slightly below those of 

 the Pacific. We fail to notice anj' indica- 

 tions of a constant temperature below a cer- 

 tain depth, such as we find in the Caribbean 

 Sea and Gulf of Mexico, where the ther- 

 mometer registers 39°. 5 at all depths ex- 

 ceeding 700 fathoms. The observations on 

 which the temperature curve is based were 

 made about the middle of August, when the 

 summer heat had nearly reached its max- 

 imum; the broken line indicates the prob- 

 able conditions at the end of February, 

 when the surface temperature is supposed 

 to remain near the freezing point of fi-esh 

 water. 



THE OKHOTSK SEA. 



In the Diagram giving an east and west 

 sectioa through the Okhotsk Sea we notice 

 in the western part the existence of a thick 

 layer of very cold water at a short distance 

 below the surface, covered by a stratum of 

 very low density but of comparativel j^ high 

 temperature. When we recall that sea 



water does not commence to congeal until 

 its temperature is reduced to below 29° 

 this cold layer furnishes an indication of the 

 severity of a Siberian winter, when the 

 whole of Okhotsk Sea is frozen over. The 

 low density of the surface water is due to 

 the fact that it is composed partly of melted 

 ice, which does not contain much salt, and 

 partly of river water, particularly that of 

 the Amur, which, after rounding the north- 

 ern point of Saghalin Island, floats south- 

 ward along its eastern shore. It is rather 

 surprising to find such steep gradients 

 in the temperatures as 54° at the surface 

 and 31° in 26 fathoms, and they can be ac- 

 counted for only by assuming that there are 

 no strong currents which keep the water 

 agitated, and furthermore that, whatever the 

 increased percentage of salt in consequence 

 of evaporation may be, it is too small to sink 

 the surface water to any considerable depth. 

 There are no temperature observations 

 available for the water under the surface in 

 the eastern part of Okhotsk Sea except bot- 

 tom temperatures ; we conjecture that dur- 

 ing the winter months there is but little 

 difference between the temperatures of the 

 eastern and western part. In the height of 

 summer, however, we may expect to find 

 about 35°. 2 the lowest temperature at a 

 depth of about 100 fathoms in the eastern 

 part. At greater depths a slight increase 

 of temperature is noticed, 36°. 3 is recorded 

 at 328 and 437 fathoms, and there appears 

 to be a nearlj' uniform temperature of 36° 

 in the great depths of the basin, which, ac- 

 cording to Moser's soundings in 1896, has 

 the shape of a trough with a steep slope 

 from the Kuril Islands, and depths exceed- 

 ing 1,800 fathoms. The densities increase 

 from 1.0222-1.0240 at the surface to 1.0246 

 at 55 fathoms and 1.0248 at 219 and 1.0254 

 at 437 fathoms. These relations of density 

 and temperature are similar to those of 

 Bering Sea, showing a continuous increase 

 of density from the surface downward and 



