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 fathoms, the friction and weight increasing to such a degree that the touch of the plummet could not be felt sensibly enough to make the fact sure; and the line would continue to run out indefinitely simply, from its own weight.

For many years, distinguished officers in the principal Naval services, strove in vain to solve the problem. Spun-yarn, silken lines, fishing lines and wire were tried, but generally, with little or no success.

Captain Denham, of H. M. S. Herald, thought he found bottom, sounding in the South Atlantic, at a depth of 46,000 feet. Lieut. Parker of the U. S. S. Congress, sounding off the coast of Brazil, ran out 50,000 feet of line, reporting no bottom at that great depth, (some 9 miles). Lieut. Walsh, U. S. N. sounded with 34,000 feet of wire without feeling bottom, and Lieut. Berryman, in the U. S. brig Dolphin, ran out a line of 39,000 feet with no more definite results.

We know now that all those soundings were defective, and that hardly more than half or two-thirds of those depths exist anywhere in the Ocean. The deepest reliable sounding yet on record was recently made by H. M. S. Challenger, between St. Thomas and Bermuda, where a depth of 23,250 feet was found.

One trouble with the small lines was that they were not strong enough to bring the sinker back to the surface, but would generally break from the strain imposed upon them at great depths; another trouble arose from the fact that the line was let run as fast as it would go out, and, in fact, was rather assisted than retarded, so that the shock of striking, communicated through the dense mass of water by the line, was not felt perceptibly enough to make the fact unquestionable, and, in short, the moment of touch was never known, but guessed at, more or less.

Again, it was almost impossible to keep a sailing vesssel directly over the line, and the drift of the ship and action of currents upon the rope, gave very imperfect results, even at depths of no more than 1,000 fathoms, and where the indications were good that bottom had been reached.