From Yokohajna to Station 2^j. 115 



Between Station 225 and 229 we observe the usual fan-like 

 arrangement of the isotherms, caused by the sinking of the 

 heavier equatorial water through the lighter strata of the polar 

 current (Plates 9 and 19). The Kuro-Siwo, running at Station 

 234 and Station 235, at a short distance from the south coast of 

 Nipon, flows, like the Gulf Stream, over and between the cold 

 waters of the Arctic current, contending with the latter for the 

 alternate possession of the romantic bays and inlets of the south 

 coast of Nipon, Sikok, and Kiusiu. A branch of the Kuro-Siwo 

 penetrates through the Straits of Korea into the Sea of Japan. 



The usual alternation of streaks of warm and of cold water 

 which characterise the scene of the meeting between equatorial 

 and polar currents was observed by the " Challenger" during the 

 last three days of her cruise to Japan. Between midnight of 

 the 8th and the morning of the nth April, 1875, the ship 

 crossed three streaks of cold water of a surface-temperature of 

 1 7° C, divided from each other by warm streaks of a temperature 

 of 20° C. The most northern streak entered the Bay of Yoko- 

 hama, falling to a temperature of 13°. 3 C. at the latter port. 

 During the stay of the expedition in Japan, while the water of 

 the Kuro-Siwo outside ranged from 20° to 23° C, the surface- 

 temperature of the bays and inlets of the south coast of Nipon 

 varied between 1 5° and 1 7° C. 



Section from Yokohama to Station 253 (Plate 18, Table 

 XII.). — This section crosses the North Pacific Ocean between 

 the parallels of lat. 34° N. and lat. 38^ N., from the coast of 

 Japan to the meridian of the Sandwich or Hawaiian Islands. 

 Its western portion exhibits the relations between the equa- 

 torial and the polar currents eastward of Nipon. After traversing 

 the belt of cold water which frinofes the east and south coast of this 

 island, we enter, ^.t Station 237, the Kuro-Siwo at the point where 

 it joins the main stream of the North Pacific Equatorial Current, 

 which flows outside the line of islands that separate the northern 



