A certain degree of knowledge regarding the nature of the bed of the Atlantic Ocean was now available; for in the summer of 1856 a series of soundings had been taken by Lieutenant O. H. Berryman, U.S.N., from U.S.N. Arctic, and also independently by Commander Joseph Dayman, R.N. (H.M.S. Cyclops), showing what was called "a gently undulating plateau extending the whole distance between Ireland and British North America." These depths (averaging about 2-1/2 miles) compared favorably with those that had presented themselves farther southward. The ground was found to shoal gradually on the Newfoundland side, but rose more rapidly toward the Irish shore. The soundings were taken with the ingenious apparatus of Lieut. J. M. Brooke, U.S.N. (Fig. 2), which formed the prototype of all similar deep-sea sounding-tubes of the present day. In this, at the extremity of the sounding-line a light iron rod, C, hollowed at its lower end, passed loosely through a hole in the center of a cannon-ball weight, A, which is fastened to the line by a couple of links. On the bottom being touched, the links reverse position, owing to the weight being taken off, and the cannon-ball, or plummet, B, being set free, remains on the ground, leaving the light tube only to be drawn up with the line.[8] In the act of grounding, however, the open end of the tube presses into the bottom, a specimen of which is consequently obtained--unless it be rock or coral. An oozy bottom was found throughout the soundings. The specimens brought up to the surface were shown under the microscope to consist (Fig. 3) of the tiny shells of _animalculæ_--the indestructible outside skeletons of the animal organisms known as _diatomaceæ_ and _globigirenæ_ foraminiferæ largely composed of carbonate of lime.[9] No sand or gravel was found on the ocean bed, from which it was deduced that no currents, or other disturbing elements, existed at those depths; for otherwise these frail shells would have been rubbed to pieces. As it was, they came up entire--without a sign of abrasion. The plateau or ridge--which was found to extend for some 400 miles in breadth--was considered a veritable feather-bed for a cable. Indeed, in his subsequent report to the United States navy, Lieut. M. F. Maury, U.S.N., spoke of this "shallow platform or table-land" as having been "apparently placed for the express purpose of holding the wires of a submarine telegraph and of keeping them out of harm's way." Lieutenant Maury concluded his report as follows: "I do not, however, pretend to consider the question as to the possibility of finding _a time calm enough, the sea smooth enough, a wire long enough, or a ship big enough_, to lay a coil of wire sixteen hundred miles in length." These words form amusing reading nowadays, as do also the suggestions of "telegraph plateaus" furnished by Providence as a resting-place for the Atlantic cable. The "plateau" idea was only