DEEP-SEA SURVEYS.

Hawke's Bay Times, Volume 17, Issue 977, 25 March 1871, Page 2

DEEP-SEA SURVEYS.

Capt. Sheraed Osborn read a paper on this subject at a recent meeting of the Royal Geographical Society, in which ha gave an account of our present knowledge of the configuration of the bed of the ocean, as derived from the Admiralty surveys and Submarine Telegraph expeditions during the last fiteen years. So level is the bottom of the Indian OceaD, that Captain Halpin, in layiug the Judian cable, stated that for hundreds of miles, there was no variation in the dynanometer of the cable's descent, and that it could have been laid at the full speed of the Great Eastern. „ Another important general fact that had resulted was the proof of the error of all former statements of very great depth of the ocean. No depth had been found greater than 2,900 fathoms (17,400 feet). It was true the Pacific had not yet been investigated; but a number of soundings had been taken in the North Pacific, and they showed a maximum depth of less than 3,000 fathoms. Professor Huxley expressed his dissent with regard to the great difference alleged to exist in the surfaces of the sea-bed and of the land ; a difference which, he contended, would not appear if both were drawn on a, true scale. This, howerer, only applied to the great general features of the surface; it took no account of the minor irregularities, which, on the land, were caused by the corroding action of rain and rivers. He was opposed to the view that the animals found living in the dark regions of the lowest sea-depths depended for light on the phosphorescence of some of the species, and saw no reason for concluding that they could not exist without light. He also doubted the accuracy of the low temperatures found at great depths, and thought that those taken in the ludiaa Ocean might be explained by the fact that they were taken with thermometers not rectified for pressure, Mr Gwyn Jeffreys was convinced, from the soundings he had himself taken, that there were great inequalities in the bed of the North Atlantic, In one case, the same dredging gave depths of 1,055 and of 740 fathoms. In the same sea, gravel was very widely spread over the bottom, and there were often extremely rough flints, which, he thought, would be dangerous to submarine cables. Many of the animals he had dredged up from great depths were amply provided with organs of sight, showing that light was. there existent. The ub narine cable of the Mediterranean was subject to the attacks of boring animals —a mollusk and a crustacean. Captain Sherard Osborn concluded the discussion by adducing, as further proof of the levelness of the deep-* sea bed, the fact that the grapnels used to recover the severed cable of 1865 (only two inches in thickness) swept across the bottom for more than 100 miles; and, in crossing the cable, scarcely ever failed to hook it, which could not have happened had there been abrupt inequalities of surface, —European Mail* Dec. 30.