DEEP SEA SOUNDINGS.

New Zealand Times, Volume XXX, Issue 4577, 20 November 1875, Page 2 (Supplement)

DEEP SEA SOUNDINGS.

Not so many years ago it was considered a feat in deep sea soundings to reach a mile or a mile and a-half, and even then, after allowance had been made for the action of currents upon the line, the actual depth attained was a good deal matter of calculation or guess. Breakages also were continually occurring in the hauling up, from the necessary slenderness of the cord in comparison with the weight of the lead. The modern method by which the lead detaches itself at the bottom meets that as well as several other difficulties nearly as important, and the wonder is that it was not thought of sooner. Now, remarks Iron, there is scarcely any limit to the depth of soundings, except the depth of the sea, which the recent explorations of the Challenger go far to show to he in accordance with the theory that its greatest depth is equivalent to the height of the highest elevations above its level. The deepest sea soundings yet effected were obtained by the Challenger this year in the abysses off New Guinea, depths which have occasioned a sharp line of demarcation between the fauna of Asia and Australasia. The “ lead" weighed 4cwt., and struck bottom at the tremendous depth of 4450 fathoms, or about 26,700 feet. The hollow rod, by which specimens of the bottom are brought up, was full of mud, and both the thermometers that had been sent down were smashed to atoms by the enormous pressure of the superincumbent water. A previous unsuccessful attempt to reach the bottom, but in which 4545 fathoms were sounded, showed the temperature at that depth to be 35kleg. Eahr., unoorrected.