The Challenger's Scientific Work in the West Paciflc.-
The following is a short account of the scientific work of the Challenger in the West Pacific Ocean :-We established seven deep-sea observing stations between Mindanao and the Admiralty Islands, and at each of these we sounded, took samples of the bottom, took a series of temperatures at different depths, and got specimens of water from surface, the bottom, and intermediate depths, for the determination of the specific gravity and for chemical analysis. At five of the seven stations, the trawl was sent down and a fair representation of the deep.sea fauna was procured. The greatest depth on this line-2,500 fathoms-we found between the Molucca Passage and the Pellew Islands. The samples of bottom varied in character according to the depth, very much as in the Atlantic.
The average temperature of the sea surface during this part of the cruise was 82.5 deg. Fahrenheit.
The serial temperature soundings seem to show that a great part of the Western Pacific is not entirely in free communication with the Southern Sea, for the water, after sinking rapidly in temperature until it reaches 34 5 deg. Fahr., at a depth of 1,500 fathoms, maintains that temperature for all the greater depths. The section from the Philippines to the Admiralty Islands may be considered to have been taken, roughly, along the Equator, as it was all between lat. 5 deg. N. and lat. 3 deg. 3 min. S. The section, 2,250 miles long, from the Admiralty Islands to Japan, was practically meridional.
The observing stations in the second section were 12 in number, and pretty regularly distributed with regard to distance. The greatest depth was found on the 23rd of March in 4,575 fathoms. This is the deepest trustworthy sounding on record, with the exception of two taken by the Tuscarora, off the east coast of Japan, in 4,643 and 4,655 fathoms respectively, but no sample of the bottom was procured on either of these occasions. The sounding in 4,575 fathoms was taken in the morning.
Only a very small sample of the bottom came up, and the depth was so unexpected that it was decided to repeat the sounding to avoid all possibility of error. In the meantime the ship had drifted a little, and the second sounding, which was most satisfactory in every respect, gave 4,475 fathoms. The tube of the sounding machine contained an excellent sample of the bottom, which was of a very peculiar character, consisting almost entirely of the siliceous shells of RadioZariu.
Three out of four Miller-Casella thermometers sent down to these depths