SCIENCE OF DIVING.

Shannon News, 29 August 1924, Page 1

SCIENCE OF DIVING.

THE EARTH'S SECRETS. HIDDEN MYSTERIES REVEALED. Recently, on a bleak hillside > in a mining .area, two experts of the South Kensington Science Museum have in turn made observations throughout the night of a remarkable instrument that has been devised in order to detect the presence 'beneath the earth's crust of minerals, oil, water, and the many other valuable deposits that are hidden below the surface.

The hazel twig of the water diviner is familiar to all, and there are still more who believe in it< implicitly. This, however, was the first occasion when really scientific . tests have been carried out in the field by. qualified .observers in England, and the results have been sufficient; to justifj the optimistic opinions held as to the instrument's capacity for accurate work that were mentioned when it was described last year in the '"Morning Post." The instrument is the Eotvos Torsion Balance, and although it is of foreign origin, one of the instruments used in these tests is of entirely; British manufacture, and was built In London. The object of the experiment was to ' ascertain the direction m which a "lode" or vein of metallic deposit extended upwards from a great depth, and to indicate at what particular points boring operations were likely to meet with the greatest , success. All the calculations are hot yet complete, but the engineers are satisfied that the instrument has justified the time spent in careful experiment, and sufficient evidence has been accumulated to. warrant faith on its efficiency. These tests, made as stated on a steep slope under adverse cpndltipns, have also refuted the statement hitherto generally accepted, that such an instrument could not be usel in a mountainous region, and was only suitable tor table land. There are many methods of gaining some idea of what lies hidden underground. Some depend upon electricity or electric-magnetic effects,! and otners upon sound. None, of these principles is applied in the case • of tno Torsion Balance, which is operated solely by the force of gravity or the attraction that is exerted by large bodies on smaller ones. Gravity Is tne force fhat attracts all .bodies towards - the centre of the earth, and the pull it exerts varies in a definite mathematical relation to the distance from the centre of the earth, and even, though the . distance between two equal weights may only be the seemingly insignificant matter of 24 inches or so, it is possible, to detect . the difference in the pull, rThe balance consists essentially of a beam sus-. pended by a delicate wire a little more than one-thousandth of an iriohin diameter. To each end of the beam a gold weight is attached, but one as carried on the beam itself, whiio the other is suspended by a fine wirs two feet long, and is therefore, that distance nearer to the centre of the earth, and though both are equal the lower weight is acted upon by a slightly greater force' than the upper. The.presence or absence underground of any material having a greater or less density than the normal soil affects the perfect balance of th«i beam and causes a twist Or tors Ton rf the filament suspending it: This is magnified by a mirror on the n.'amoht, which reflects a .spot of li'rht on to the scale, and thus the slightvst disturbance in the delicate balance is rendered apparent to the observer, who must have the skill n.-cessary to interpret adequately the readings of the instrument. The vital parts of the instrument are enclosed in triplewalled brass cases in order to protect them from temperature and electrical disturbances, and problems arising from the sun's radiation are overcome by using the instrument only at night.

Not the least curious feature of the instrument Is that, .-while'it.'.can detect a deposit of salt, oil, or ore, it is also sensitive to a hole or underground cave; and this is an accomplishment that no other known method affords. For example, a tomb such as Tutankhamen's would afford a clear indication that the subsoil was not uniformly l*>lid ground, and would thus suggest that digging at a given spot would probably result in something out of the ordinary being found, though it should be emphasised that the instrument is not intended to detect hidden treasure of its own accord, and can only give indications when placed over a site that the observers consider likely to yield fruitful results. In this, however, we* 'the real economy of the balance, for if there is nothing to be found it can prevent the useless expenditure of capital an>d labour by the expensive method of haphazard trial bores. It is for this specific raason that the recent field researches have been carried out, and the engineers in charge consider that they ore amply repaid by the results obtained for their long spell of isolation far from railways or other disturbing influences.