The ocean world : being a descriptive history of the sea and its living inhabitants / Chiefly translated from "La vie et les moeurs des animaux".

  • Figuier, Louis, 1819-1894.
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: The ocean world : being a descriptive history of the sea and its living inhabitants / Chiefly translated from "La vie et les moeurs des animaux". Source: Wellcome Collection.

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    Laplace found, on astronomical consideration, that the mean depth of the ocean could not be more than ten thousand feet. Alexander von Humboldt adopts the same figures. Dr. Young attributes to the Atlantic a mean depth of a thousand yards, and to the Pacific, four thousand. Mr. Airy, the Astronomer Royal, has laid down a formula, that waves of a given breadth will travel with certain velo- cities at a given depth, from which it is estimated that the average depth of the North Pacific, between Japan and California, is two thousand one hundred and forty-nine fathoms, or two miles and a hall. But these estimates fall far short of the soundings reported by navi- gators, in which, as we shall see, there are important and only recently discovered elements of error. Du Petit Thouars, during his scientific voyage in the frigate Venus, took some very remarkable soundings in the Southern Pacific Ocean: one, without finding bottom at two thousand four hundred and eleven fathoms; another, in the equi- noctial region, indicated bottom at three thousand seven hundred and ninety. In his last expedition, in search of a north-west passage, Captain Ross found soundings at five thousand fathoms Lieutenant Walsh, of the American Navy, reports a cast of the deep-sea lead, not far from the American coast, at thirty-four thousand feet without bottom. Lieutenant Berryman reported another unsuccessful attempt to fathom mid ocean with a line thirty-nine thousand feet in length. Captain Denman, of H. M. S. Herald, reported bottom in the South Atlantic at the depth of forty-six thousand feet; and Lieutenant J. P. Parker, of the United States frigate Congress, on attempting soundings near the same region, let go his plummet, after it had run out a line fifty thousand feet long, as though bottom had not been reached. We have the authority of Lieutenant Maury for saying, however, that “ there are no such depths as these.” The under-currents of the deep sea have power to take the line out long after the plummet has ceased to sink, and it was before this fact was discovered that these great soundings were reported. It has also been discovered that the line, once dragged down into the depths of the ocean, runs out unceasingly. This difficulty was finally overcome by the ingenuity of Midshipman Brooke. Under the judicious patronage of the Secretary to the United States Navy, Mr. Brooke invented the simple and ingenious apparatus (Fig. 1), by which soundings are now made, in a manner