SIX MILES DEEP.

Auckland Star, Volume LVIII, Issue 20, 25 January 1927, Page 9

SIX MILES DEEP.

PLUMBING THE OUTER OCEANS

Considerable interest has been caused by the report that the Japanese naval surveying ship Manshu recently obtained a sounding of 31,000 ft between Izu and the Bonin Islands; and it has been | stated that this is the deepest known spot in the Seven Seas, easilv beatinn- th« famous Tuscarora Deep of 27,900 ft which was named after the American warship which made the sounding (declares the London Daily Xews"). The new soundmg certainly does beat this, but it is itself beaten by two others. The German surveying ship Planet, in 1914, got bottom at 32,112 ft east of the Philippine Islands, while the Manshu herself, surveying in August, 1024, failed to find bottom with 32.04Cft of wire out. It is interesting to note that, whereas fhere are cjuite a number of elaborate sounding machines on the market— machines which register the depth of water by the compression of air in a sensitised tube—whieh are used by -ill linei s, it is still necessary, wheu it oomes to great depths like this, to employ the same method that was employed by the \ isings and Phoenicians— a heavy weight on the end of a line. Nowadays the line is the finest piano wire, but when Ross was surveying the Wcddell Sea he used an ordinary cod line, which was constantly breaking. On one occasion he reported 4000 fathoms — 24,000ft —and no bottom, which was regarded as a wonderful sounding. Un- [ fortunately, it was afterwards proved i that his men failed to notice the slight j check on the line which told tliat the 1 weight had hit the hgttoin of the sea, j and had continued to allow the line to run out by its own velocity, and by the . tide. Actually there was 2-500 fathoms I of water in tiiis spot.