DEPTH OF THE OCEAN GENERAL RESULTS As the details of the depth of particular parts of the ocean will be included in the special geography of each ocean, it will suffice here to summarize the principal results of recent observations as to the depth of the ocean. The formerly general notions of enormous depths-40,000 to 50,000 feet— have been entirely dispelled. Actual measurements prove that a very large proportion of the ocean is not more than 2,000 or 3,000 feet deep, and yet four miles is frequently given as the mean depth of the sea ; if so, extensive portions must be eight or ten miles deep. But it is most improbable that there are depths of more than six miles. The Challenger expedition of 1872-6 ascertained the depth at 150 stations in the Atlantic, and at 100 in the Pacific, and the general results show that the average depths of the ocean does not exceed 2,000 fathoms; while the greatest depth recorded, found in the Pacific, north of New Guinea, was only 4,575 fathoms, or 27,450 feet, or nearly si miles. In the Indian
Ocean, the greatest depth found was 2,254 fathoms, or 13,524 feet.
Both the Arctic and Antarctic Oceans appear to be much shallower than any of the other three oceans. The depth in the Arctic Ocean, at a point 400 miles from the pole, was found to be only 72 fathoms, or 432 feet, while the greatest depth yet found within the Antarctic Circle was 1,975 fathoms, or 11,850 feet. The supposition that the depths of the sea generally correspond to the heights of the land is thus veri fied; not that there is any necessary connection between the two, for striking disparity would be expected from the great difference in area of the sea and the land. As it is, however, the greatest known depths of the ocean correspond very nearly to the highest known elevation on the land.