LOST WORLDS

Ashburton Guardian, Volume 56, Issue 62, 24 December 1935, Page 8

LOST WORLDS

LYING BENEATH THE SEA. The discovery of the wreck of the Lusitania off the Irish coast is one of the most recent dramas of a fascinating modern science—undersea exploration. A new mountain peak has been found in the Atlantic by a French cable ship, the Ampere. It is only 195 feet below the surface, writes R. L. Hadfield in the Sydney “Telegraph.” The Ampere was engaged in repairing the submarine cable between Brest and Casablanca, a cable which, formerly German, was cut and diverted by a British vessel during the war, when it discovered the peak. Its position is 35.5 IS', and 13.55 W., that is, about 400 miles west of Gibraltar. To the oceanographer the discovery of a new feature of this description is every bit as thrilling as would be a new Matterhorn to the mountaineer or geographer. It adds one more item to his considerable knowledge of that part of the earth’s surface which lies under water and which is, of course, greater than the unsubmerged area. Within the past lifty years oceanography has become a true science, and as a result of expeditions sent by scientific societies and of Government surveys almost the whole of the bed of the sea has been mapped and explored with the same, thoroughness as is exhibited by ordinance surveyors at work in the valley and on the hills of dry land. Within the last two years discoveries in the sea have strengthened belief in the former existence of the continent of Gondwanaland, lying between India and South Africa. What are believed to he the highest peaks of this continent reach above the surface of the sea, and arc known to us as the Seychelle Islands. One of the most interesting discoveries in connection with this “lost continent” is the fact that across a great submerged plain lies a deep gully, conjectured to be the ancient bed of the River Indus.

These discoveries link up with previous knowledge of another submerged land, the “Empire of Zabedj,” between the coast of China and Ceylon, and tend to prove that the Indian and Pacific Oceans were once dry land, with the present islands of Polynesia as mountain peaks. Survey ships and cable ships are now provided with instruments with which the sea-bed can be explored with almost as much thoroughness as if divers went down with notebook and pencil. The chief instrument for this purpose js the sounding machine, of which there are two types, the wire-and-sinker type, and the sonic type. The first, as its name implies, incorporates a wire (piano-wire) and a weight. The weight carries down with it brass tubes open at the bottom; these arc forced into the bottom by the momentum of the drop, and thus take samples of the ground. The tubes can only, be used in the ease of comparatively soft sea-bottom; when this is bard, an instrument known as a “snapper” is used. The snapper incorporates two jaws, kept apart by a finger; on hitting the bottom the finger is displaced, the jaws close with a snap, and thus bite out a sample of the soil. In addition, it is usual to take the temperature of the water at the bottom of the sea, this information being necessary to submarine-cable manufacturers. Curiously enough, tlie temperature of the sea-bottom is much the same over about 87 per cent of the sea’s entire area, being about 3odeg. Falir., whether at the Equator or in the North Sea. Tho heat from tlie sun penetrates less than 25 fathoms below the surface. When no • samples or temperatures are required, the Sonis sounder js used. This instrument incorporates a gong, hammer, and microphone. Its principle is the catching of an echo from the bottom of the sea, calculation from the time taken for the echo to return, giving tho depth, of water. The gong, hammer and microphone arc attached to the ship’s skin below the waterline, leads from the lattei being taken to headphones i,n the ship’s wheelhouse. The navigator listens to the headphones and v atclies a dial marked off in fathoms. When the needle on the dial points to zero, a blow on the gong is given, and at the same time the needle begins to move, tlie instrument being so adjusted that when the navigator hears the echo tlie number on the dial to which the needle points is the depth in fathoms. One of the great advantages of this sounder is that the ship does not have to he stopped, and only when taking very deep soundings—when, of course, the echo is faint—do any extraneous noises in the ship, such as the chipping of rust from anchor cables, have to he stopped. Such instruments as these, combined with tlie “dredge” with which shellfish and other living organisms are brought up from the bottom, are enabling the extent, shape and nature of all the land lying under the sea to become known to us, and in some eases very strange discoveries have been made. For instance, in a great area in the Gulf of Oman, near Muscat, the seabottom smell like rotten eggs through the presence of sulphuretted hydrogen, and is absolutely devoid ot living creatures. It is supposed that there is great seepage into the sea from petroleum regions in the very bowels of the earth.