While Cook was speculating on the cause of this phenomenon, and was in the act of ordering out the boats to take soundings, the " Endeavour " struck heavily, and fell over so much that the guns, spare cables, and other heavy gear had at once to be thrown overboard to lighten the ship. As day broke, attempts were made to float the vessel off with the morning tide; but these were unsuccessful.
Was almost wholly derived from the soundings of the expedition of Sir J.
Long., in which he recorded a depth exceeding 4000 fathoms. The Scottish Antarctic expedition has shown this sounding to be erroneous; the " Scotia " obtained samples of bottom, in almost the same spot, from a depth of 2660 fathoms. Combining the results of recent soundings, Dr W.
Borings and soundings taken at Funafuti in 1897 indicate almost beyond doubt that the whole of this Polynesian region is an area of comparatively recent subsidence.
215 surround it, and most of its area has a depth exceeding 400 fathoms, the maximum depths along three lines of soundings taken across it being 491, 485, and 476 fathoms respectively.
A few soundings made outside this coast seem to indicate that the fjords continue as deep submarine valleys far out into the sea.
Deep. The deepest soundings give only 50 to 55 ft., the average depth being 30 to 40 ft.
There the bottom slopes very abruptly, descending precipitously at a point not far from the north-east coast of the main island, where soundings have shown 4655 fathoms. This, the deepest sea-bed in the world, is called the Tuscarora Deep, after the name of the United States man-of-war which made the survey.
Deep soundings were made in the Atlantic coasts of the North Sea and Baltic, when the rise may amount for this purpose by vessels both of the British and of the American to very many feet.
In the region of tropical hurricanes the navies, while in the Mediterranean and in the Indian Ocean converging wind system of a circular storm causes a heaping many soundings were made in connexion with submarine up of water capable of devastating the low coral islands of the cables to the East.
The last-named vessel secured 157 trustworthy deep soundings, Deep-sea Soundings.
Polar explorers making sections across the great expanses of water with everfrequently repeated those experiments in deep-sea soundings, increasing accuracy, and in that work the government surveying both William Scoresby and Sir John Ross obtaining notable ships have also been engaged, vast stretches of the Indian and results, though not reaching depths of more than 1200 fathoms. Pacific Oceans having been opened up to knowledge by H.M.SS.
In 1854 attaches to the soundings of the German deep-sea expedition J.
The soundings of the Dutch expedition on hung on the sounding-tube that it was automatically released the " Siboga " during1899-1900in the eastern part of the on striking the bottom and left behind, while the light brass tube Malay seas and those of the German surveying ship " Planet " containing a sample of the deposit was easily hauled up. This in 1906 in the South Atlantic, Indian and North Pacific Oceans principle has been adopted universally for deep soundings, and were notable, and Sir John Murray's expedition on the " Michael is now applied in many forms. In 1855 Maury published Sars " in the Atlantic in 1910 obtained important results.
The soundings are made by means of a special machine fitted with a brake so adjusted that the revolution of the drum is stopped automatically the instant the lead touches the bottom, and the depth can then be read directly from an indicator.
It is improbable, however, that the smooth and slender wire is much influenced by currents, and the best deep-sea soundings may be taken as accurate to within 5 fathoms.
- Recent soundings have shown that the floor of the ocean on the whole lies some 2 or 3 m.
Particularly steep slopes are found in the case of submarine domes, usually incomplete volcanic cones, and there have been cases in which after such a dome has been discovered by the soundings of a surveying ship it could not be found again as its whole area was so small and the deep floor of the ocean from which it rose so flat that an error of 2 or 3 m.
In spite of the increase of deep-sea soundings in the last few decades, they are still very irregularly distributed in the open ocean, and the attempt to draw isobaths (lines of equal depth) on a chart of the world is burdened with many difficulties which can only be evaded by the widest generalizations.
All soundings exceeding 4000 fathoms, occur in trenches, and there are only a few small trenches known (on the west coast of Central America) in which the maximum depth is less than 3000 fathoms. Jlost trenches are narrow, but of considerable length, and their steeper side is believed to be due in every case to a great fracture of the earth's crust..
The rise resumes a southerly direction and from Ascension to Tristan d'Acunha, the depth is in many places less than r50o fathoms. The soundings of Bruce's Antarctic expedition in the " Scotia " showed that the rise cannot be traced beyond 55° S.
The existence of the latter, which extends to the African continent, was announced by Sir Wyville Thomson in 1876 as a result of his discussion of the deep-sea temperature observations of the " Challenger " expedition, though the fact was not confirmed by soundings until many years later.
The Mediterranean Sea, the best-known member of the intercontinental class, is separated from the Atlantic Ocean by a ridge running from Cape Spartel to Cape Trafalgar on which the greatest depth is only 175 fathoms. The depth increases so rapidly towards the east that soundings exceeding 500 fathoms occur off Gibraltar.
Globigerina ooze was recognized as an important deposit as soon as the first successful deep-sea soundings had been made in the Atlantic. It was described simultaneously in 1853 by Bailey of West Point and Ehrenberg in Berlih.
The soundings made by the "Challenger" and "Gazelle" and the affinities which in certain respects exist between the islands, seem to point to the existence at one time of an extensive land area in this quarter, of which Kerguelen, Prince Edward's Islands, the Crozets, St Paul and Amsterdam are the remains.
He went to the mines for a season, and there he began to write in the local newspapers, adopting the pen name of "Mark Twain," from a call used in taking soundings on the Mississippi steamboats.
The average depth varies from 1500 to 2500 fathoms, and from this level innumerable volcanic ridges and peaks rise almost or quite to the surface, their summits for the most part occupied by atolls and reefs of coral formation, while interspersed with these are depressions, mostly of small area, among which the deepest soundings recorded have been obtained.
His careful and detailed maps, lake soundings, hydrographic, geological, meteorological and other investigations gave him the highest rank among modern explorers.
And soundings of over 30 ft.
Outside the delta, in the Bay of Bengal, is a deep depression known as the " swatch of no ground "; all around it the soundings are only of 5 to io fathoms, but they very rapidly deepen to over 300 fathoms. Mr J.
This journey practically removed from the map the doubtful Keenan Land (reported vaguely in the 'seventies of last century), while soundings taken during the drift of the " Karluk " and other journeys of the expedition show a narrow continental shelf, and reduce the probability of land existing in the western part of the Beaufort Sea.
In the middle of the gradually narrowing channel three depressions are known to exist; soundings in two of these are: i 1 io fathoms in zo° N.
Jour., March 1907 and July 1908.) Its greatest ascertained depth is some 270 ft., which compares with soundings of 2000 ft.
Large portions of the bed still remain unexplored, but a fair knowledge of its general form has been gained from the soundings of H.M.S.
Here the tidal phenomenon called the bore, or Pororoca, occurs, where the soundings are not over 4 fathoms. It commences with a roar, constantly increasing, and advances at the rate of from 10 to 5 m.
This length has been standardized to a measure of 6 ft., and as such is used mainly in soundings as a unit for measuring the depth of the sea.
Second only to the compass in its value to the sailor is Thomson's sounding apparatus, whereby soundings can be taken in 100 fathoms by a ship steaming at 16 knots; and by the employment of piano-wire of a breaking strength of 140 tons per square inch and an iron sinker weighing only 34 lb, with a selfregistering pressure gauge, soundings can be rapidly taken in deep ocean.