750 
THE YOYAGE OF H.M.S. CHALLENGER. 
to lose its distinctive character. During the northeast monsoon a cold surface current 
is running to the southward from the Japan and Yellow Seas. It appears therefore 
highly probable that the Equatorial Current, instead of losing itself as is supposed, 
when it meets with the cold water from the Japan and Yellow Seas, is diverted to the 
eastward along with a cold northerly current, the two running together side by side 
without intermingling their waters. When the northeast monsoon ceases the current 
from the Japan and Yellow Seas also ceases, which causes the slackness of the Kuro 
Siwo, south of Nipon Island, in June, as it is then only due to the Equatorial Current. 
Later on, in July and August, when it is augmented further by the surface drift from 
the China Sea in the southwest monsoon, it runs again with great rapidity, and is 
wholly a warm current. These peculiar effects are probably not experienced to the 
eastward of the meridian of 140° E. ; there apparently the stream is always a warm one. 
While passing through the Japan Stream the tow-net observations also indicated 
water from two different sources. When in the colder streams there were very many 
more small Diatoms, Notilucce, and Hydromedusse than in the warmer streams, where 
the same pelagic animals that were obtained all the way from the Admiralty Islands 
prevailed. Many similar instances occurred during the cruise, where the approach to land 
or the presence' of shore water was indicated by the contents of the tow-nets. 
Japan to the Sandwich, Islands.. 
On the 16th June the Expedition left Yokohama for the Sandwich Islands, with 
the intention of running a section across the Pacific on the 3.5th parallel of north latitude 
as far east as the meridian of Hawaii, and then proceeding southwards. At 10 p.m. 
Susaki bearing N. ^ E. and No. Sima light E.N.E.., a course was shaped to the south- 
eastward for a good position in which to sound (see Sheet 36)., 
On the 17th, at 4 a.m., a sounding, trawling, and temperatures were taken in 1875 
fathoms in lat. 34° 37 ; N., long. 140° 32' E. Whilst the vessel was trawling the Japan 
Stream was setting to the eastward at the rate of 1^ miles per hour, the temperature 
of the surface water being 73°. 
The deposit at this Station was a blue mud with a thin reddish surface layer, and 
contained 5 per cent, of carbonate of lime, which consisted chiefly of a few pelagic and 
other Foraminifera and Coccoliths. 
The trawling was a very successful one, for the net contained a large quantity of mud, 
several large pieces of pumice, a hardened block of the bottom deposit over a foot in 
diameter, some fragments of plants, and a large number of deep-sea animals. In the 
washings of a very large quantity of mud one Ianthina shell, three or four Pteropod shells, 
the vertebra of a fish, and the beak of a large Cephalopod were found. The hardened frag- 
ment of the deposit contained the same mineral particles and organisms as the soft mud 
