SCIENTIFIC DIVINING.

Hauraki Plains Gazette, Volume XXXV, Issue 4734, 6 August 1924, Page 1

SCIENTIFIC DIVINING.

EARTH’S DEPOSITS REVEALED, TESTS OF INSTRUMENT. 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 divider is familiar to all, and there are still many who practise this art, and still more who believe in it implicitly. This, however, was the first occasion that really scientific tests have been carried out in the held by qualified observers in England, and the results have been sufficient to justify the optimistic opinions held as to the instrument's capacity for accurate work tli at .were mentioned when it was described last year in the “Morning Past.” 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 in which a “lode” or vein of metallic deposit extended upwards, from a great depth,, and to indicate at what particular points future boring operations were likely ,to meet with the greatest success. All. the calculations are not 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 in its efficiency. These tests, made as stated on a steep slope under adverse conditions. have also refuted the (statement, hitherto generally accepted, that such an instrument could not be used in a mountainous region, and was only suitable for tableland. There are many methods cl gaining some idea of what lies hidden under-' ground.. Some depend, .upon electricity or electro ( magnetic effects and others,, upon sound. None of these principles is applied in. the case of the Torsion, Balance, y’hich is operated, solely by the force of gravity or the attraction that i|S exerted by large bodies on .smaller .ones. Gravity is the force that attracts all,bodies towards the centre of the earth, and.the pull it exerts varies in a definite mathematical relation to the. distance of the body from the centre of the earth, and even though the distance between two equal Weights may only l>e the seemingly insignificant matter of 24 inches or so, it is possible to detect toe difference in the pull. The balance •consists essentially of a beam suspended by a delicate wire a little more chan one-thousandth ol an inch in diameter. To each end of the beam a gold weight is attached, but one is carried on the beam itself while the other is suspended by a fine wire 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 the beam and causes a twist or torsion of the filament suspending it. This is magnified by a mirror carried on the filament, which reflects a spot of light on to a scale, and thus the slightest disturbance in the delicate balance is rendered..apparent to .the- observer, who must have the skill necessary 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. iinderground cave, and Ahis is an accomplishment that no. 1 other known method affords. For example, a tomb such as Tutankhamen’s would afford a, clear indication that, the subsoil. was not uniformly solid 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 ,i|s 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, lies the real economy of the balance, for if there is nothing to be found it can prevent the useless expenditure of capital and laboui by the expensive method of haphazard trial borings. It is for this specific reason, that the recent field reeearyhea have been carried out, and the ,ei gineers in charge consider that they are amply repaid by the results obtained for their long spell of Isola; tion far from railways or other disturbing influences.