December 30, 1898.] 



SCIENCE. 



943 



the existence of a minimnm of temperature 

 at the depth of about 100 fathoms, separa- 

 ting the much warmer surface waters from 

 the slightly warmer deeper waters. Hence 

 Okhotsk Sea, like Bering Sea, must receive 

 a supply of salt and heat from a connect- 

 ing sea by a current which starts at the 

 surface and during its progress gradually 

 sinks to the greatest depths. The Okhotsk 

 Sea connects with the Japan Sea by La Pe- 

 rouse Strait and with the Pacific by the 

 Passages throngh the Kurils, and it may re- 

 ceive its supply of salt from either of these 

 seas, but the observations by Makaroff in 

 1887 and Moser in 1896 point towards the 

 .Japan Sea as the source. Makaroff found 

 in La Perouse Strait three kinds of water, 

 each of a distinctive physical character. In 

 the southern part he found dense and warm 

 water, with indications that it was from the 

 Japan Sea on its northward way. In the 

 northern part he found warm and light sur- 

 face water similar to that we encounter far- 

 ther north, off the shore of Saghalin Island; 

 it is probably composed of melted ice and 

 the waters of the Amur and other rivers 

 which have come down from the northward 

 along Saghalin Island. This surface water 

 rests on water which has considerable den- 

 sity but a very low temperature ; it is of the 

 same character as that cold stratum which 

 we found underlying the warm surface 

 waters in a higher latitude, and we may, 

 therefore, conclude that along the entire 

 eastern shore of Saghalin Island the water 

 below the depth of 25 fathoms receives but 

 a small increase of temperature in conse- 

 quence of the summer's warmth. Where 

 it meets the water from the Japan Sea it 

 rises to the surface in a streak which ex- 

 tends from Cape Crillon forty miles in a 

 southeasterly direction, effectually shutting 

 off the Japanese current from the western 

 part of Okhotsk Sea. Moser's density ob- 

 servations show that this current advances 

 northward in the eastern part of the Sea, 



passing along the Kuril Islands, and that it 

 is gradually overlapped by the lighter water 

 to its left, thus verifying Makaroff-s views, 

 according to which the waters from the 

 Japan Sea, after reaching the Okhotsk Sea, 

 continue to sink until they occupy all the 

 deeper parts of this basin. The depth of 

 La Perouse Strait is but 35 fathoms. The 

 passages through the Kurils are probably 

 much deeper. Makaroff gives 235 fathoms 

 for the Amphitrite Strait, and from Moser's 

 temperature observations, we infer that 

 about 800 fathoms' depth may be carried 

 from the Pacific into the Okhotsk Sea- 

 From this we may conclude that, if the Ok- 

 hotsk Sea does not receive a supply of salt 

 and heat through an undercurrent from the 

 Pacifi^c, it is not on account of an insuffi- 

 cient depth of channel, but due to a greater 

 difference between the physical condition of 

 the waters of the Okhotsk Sea and those of 

 the Japan Sea than exists between the for- 

 mer and those of the Pacific adjoining. The 

 cold zone along the Kuril Islands was for- 

 merly thought to be due to the eflFect of 

 cold currents which' were supposed to come 

 from the neighborhood of Kamchatka, but 

 Makaroff correctly attributes the low tem- 

 perature to a commingling of the cold water 

 from lower strata with the surface water. 

 There are instances where cold water rises 

 to the surface in consequence of peculiar 

 conditions of density and temperature, as in 

 the case of the cold streak at the equator 

 off the west coast of South America ; but in 

 the present case an inspection of the dia- 

 gram will show that the rising is confined 

 to the upper stratum of 25 fathoms' depth, 

 and that it should be attributed to the bot- 

 tom configuration, which offers formidable 

 obstructions to the movements of a formi- 

 dable tidal current sweeping through the 

 passages four times a day. 



THE CENTRAL PACIFIC OCEAN. 



The Diagram shows a section of the Pacific 



