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wire a small weight is attached; to this, one end of twenty-five fathoms of rope, to the other end of which hangs a much larger weight with a cup for bringing up specimens from the bottom. The existence of the two weights and the very important part played by them was not, I think, grasped by many during the reading of the paper. This wire is wound on a drum, made as little massive as possible. The motion of the drum is regulated by an exceedingly simple friction break, which is so adjusted that when the lower and heavier weight has nearly reached the bottom the retarding force is a little less than the total strain on the wire, but much greater than that strain becomes when the lower weight rests on the bottom, consequently the moment the bed of the ocean is reached the paying out gear automatically stops,—the wire hangs practically vertical without slack, and the total amount run out indicates the true depth. After arranging this apparatus one of the early difficulties experienced by Sir William was to obtain thin wire of sufficient strength. This he at last succeed in doing by the employment of piano-forte wire. But as the thin piano-forte wire is not that which is commonly used for sounding the deep C, considerable judgment had to be employed in the selection of wire of only the best quality. Another difficulty experienced was that it was necessary to make the drum on which the wire was wound very slight, for unless its mass is kept small the momentum the wheel would acquire by its rapid rotation would be such as to prevent it being suddenly stopped by the friction break when the weight reached the bottom. On the first trial of this apparatus when Sir William was making soundings in the Bay of Biscay the accumulated strain of the wire, produced on coiling in, completely crushed the slight drum on which it was wound, so that it became necessary for those engaged to seize the wire with their hands to pull it up. However, although the depth of the sea there is over twelve hundred fathoms, and although there were only two or three men in the small boat from which the soundings were being made, Sir William succeeded, by aid of that indomitable energy and perseverance that has characterised all his undertakings, in bringing up specimens of the bottom which he exhibited at that meeting of the British Association. Perhaps Captain Belknap will kindly give as the results of his experience with reference to the crushing of the drum, also whether he knows why the Challenger has made, as far as I know, no use of the wire apparatus that was supplied them.
Captain Belknap, in reply to various inquiries, stated that they had been quite successful in bringing up specimens of the bottom; that corals were found at a depth hitherto unthought-of; that evidences of life were found at the greatest depths; and that he had found it necessary once and again to strengthen the drum employed in the method of Sir Wm. Thompson, with whose views he was well acquainted, and who sympathized cordially with the work now being performed by the Tuscarora.
