interval, to determine the depth. This plan would afford no specimens of the bottom, and its adoption was opposed by other obstacles. One gentleman proposed to use the magnetic telegraph. The wire properly coated, was to be laid up in the sounding-line, and to the plummet was attached machinery, so contrived that on the increase of every 100 fathoms, and by means of the additional pressure the circuit would be restored, somewhat after the manner of Dr. Locke's electro-chronograph, and a message would come up to tell how many hundred fathoms up and down the plummet had sunk. As beautiful as this idea was, it was not simple enough in practical application to answer our purposes.
564. Physical problems more difficult than that of measuring the depth of the sea have been accomplished.—Greater difficulties than any presented by the problem of deep-sea soundings had been overcome in other departments of physical research. These plans and attempts served to encourage, nor were they fruitless, though they proved barren of practical results. Astronomers had measured the volumes and weighed the masses of the most distant planets, and increased thereby the stock of human knowledge. Was it creditable to the age that the depths of the sea should remain in the category of an unsolved problem? Its "ooze and bottom" was a sealed volume, rich with ancient and eloquent legends, and suggestive of many an instructive lesson that might be useful and profitable to man. The seal which covered it was of rolling waves many thousand feet in thickness. Could it not be broken? Curiosity had always been great, jet neither the enterprise nor the ingenuity of man had as yet proved itself equal to the task. No one had succeeded in penetrating and bringing up from beyond the depth of two or three hundred fathoms below the aqueous covering of the earth any solid specimens of solid matter for the study of philosophers.
565. The deep-sea sounding apparatus of Peter the Great.—The honour of the first attempt to recover specimens of the bottom from great depths belongs to Peter the Great of Russia. That remarkable man and illustrious monarch constructed a deep-sea sounding apparatus especially for the Caspian Sea. It was somewhat in the shape of a pair of ice-hooks, and such as are seen in the hands of the "ice-man," as, in his daily rounds, he lifts the blocks of ice from his cart in the street for delivery at the door. It was so contrived that when it touched the bottom the plum-
