THE-GREEDY OCEAN.

Lyttelton Times, Volume LXXIV, Issue 9168, 30 July 1890, Page 6

THE-GREEDY OCEAN.

The greedy ocean—as Horace terms the] boundless expanse of waters that joins’the! nations it divides—not only patsa period! to the checkered career of many a skilful) seaman, but also engulfs stately ships andj the toil-won treasures which theyperchance). contain. It is, however, much more the! friend of man than his enemy. ThehumanJ race have not been slow to devise means! whereby some portion of the spoil can be) recovered from the fabled home of Neptune) and the Nereids. Seeking for treasure at) the bottom of old ocean partakes somewhat' of the nature of a lottery, with few prizes) and many blanks: but it has attracted thej attention of adventurous spirits making j haste to get rich under every sky., Itfisj. the correct thing nowadays to form suchi a venture into a Limited Liability Compiany I as though it were a silver mine or any; other terrestrial undertaking. Jules Verna;, has delighted his numerous readers by his;' extravagant descriptions of submarine! forests, pearls worth ten million francs and; as large as acocoanut, and gigantic oysters.' Scientific expeditions have failed to meett with any of these marvellous ocean treasures! evolved from the inner consciousness of the; famous writer of fiction in a motley garb of| distorted facts. They have, however,! acquired other deep-sea treasures, which,! although, valueless on ’Change, and pro-; bably classed with the veriest rubbish by! matter-of-fact men of business, have proved! important factors in determining a more ac-j curate knowledge of marine zoology and! botany. Then, again, there are those more) humble toilers of the sea, divers for pearl and; sponge, who perform their arduous tasks! without extraneous aid. The length o£• time spent under water by these men, after) leaving the upper air, is limited by their] powers of endurance; Hence, neither; extensive nor prolonged submarine opera-) tions could be effected in this way., Wol are concerned more immediately with! greater gain. Diving-bell, waterproof] suit and helmet, and electric light, have) done much to render work underwater a) success. When constructing the founda-j tions of a bridge, or repairing a leaky) place in the immersed portion of a ship’s; hull, it is often absolutely necessary) that men shall remain beneath the! surface of the water while the work is pro-! ceeding. It is true that a coffer-dam might) be built up; but this would be.more; costly and less speedy. The diving-bell—! a large hollow iron vessel—supplies this) pressing need indifferently. It has an) opening at its base, as its name implies; it' is provided with inside accommodation for; the workers; and is sufficiently strong to; withstand the pressure of the Buperin-) cumbent mass of water. All being ready) and everyone in his place, the bell is! gradually lowered by suitable apparatusbeneath the surface of the water. The 5 air which it contains is compressed, and) the water rises a little inside; but all) above remains dry and snug. Powerful) force-pumps connected with the top of the) bell keep up a supply of pure air and) prevent the air space from being further) encroached upon by the water. Submarine j work can be carried on by this means; but) operations are necessarily confined to the) area beneath the bell. The diving bell has! a certain claim to antiquity, if the accounts) of Aristotle and Jerome be accepted. Friar | Bacon is said to have constructed one! about the year 1250; bub the earliest; reliable account of its use in Europe would) appear to be that of the descent of two! Greeks at Toledo in 1538 in the presence of) the Emperor Charles V. They went under j the water " in a very large kettle, suspended ■■ by rope, mouth downward.” The astron-) omer Halley has the merit of inaugurating) submarine work in this country; for he' not only improved on the crude ideas of his; day, hut actually descended forty-five feet) in a bell of his own arrangement at the begin* • ning of the eighteenth century. Smeaton 1 was the first to employ diving bells for; civil engineering purposes; and he con-) sfcructed Ramsgate Harbour by their aid in : 1780. |

The discovery of the properties of india-! rubber had an important bearing on the) success of ocean treasure-seeking. It is' an instance of an improvement in one) branch of industry leading to unforeseen; development in another. By discarding; the bell and adopting a waterproof suit; and helmet, a diver is free to make his; way into the holds of sunken, ships which' must otherwise have been .inaccessible.' We have often watched a diver) performing his toilet. He gets into) a waterproof suit; his assistants place) in position his massive metallic helmet,; which, resting upon his shoulders, covers' head and neck; leaden-soled shoes are) placed upon his feet; and he is ready to: descend. Helmet and suit are! carefully, connected, so that water cannot insinuate; itself between them. The helmet , has! glass windows, to enable the diver to see,! and its upper part is fitted with a flexible) tube for supplying him with fresh atmos* pheric air from a force - pump. Excess) and vitiated air escape by a suitable valve.] A rope is attached to a diver’s body, by) which he is hauled up to the surface if; necessary, and by which he can 'make preconcerted signals with his attendants above. Both rope and air-supply tube are! allowed to run out, or the slack taken in,) according to the movements of the oper-j ator below. Any fouling of the-tube, or; its severance, may mean sudden death for) the diver. :J j Water exerts great pressure on a diver i even at moderate depths. Every thirty) feel of descent represents an additional! weight of another atmosphere, or, speaking! roughlyyan extra pressure of about fifteen! pounds on the square inch. Practice has! unequivocally demonstrated that a I submarine worker breathes without much! effort, has control over all hia organs, and; preserves bis presence of mind down to > about one hundred and twenty feet; but) below one hundred and fifty feet $9 external pressure produces uncontrollable' physiological effects upon hia . internal! organs, and life is endangered. Ainas) becomes more accustomed to the differential between the normal atmospheric pressure! and the increased pressure of the water by) gradually increasing the depth of decent.) His progress both from and to the surface) must be accomplished slowly, in, order that humming in the ears andptfinaAn the bead may be avoided. Electricity - enables a diver to partly dispel the gloom of hi* uncanny workplace ; but under the; most! favourable circumstances his sight in the' denser medium is far from being micro*: scopically perfect. ]