A MODERN MARVEL

Evening Post, Volume CV, Issue 122, 25 May 1928, Page 8

A MODERN MARVEL

SOUNDING THE EARTH GEOPHYSICAL PROSPECTING (From "The Post's" Reoresentative.) ( SYDNEY, 17th May. Mr. A. Broughton Edge, a famous English consulting geologist, now visiting Australia on an important mission for the Commonwealth, is an expert in ■ what is lenown as. geophysics, and ,he is about to embark one one. of the largest experiments ever promoted in ; Australia. ; The cost will run into thousands of pounds, but the return, if the experiment is successful, will run to millions. As a result it is hoped that tho rich mineral resources of the country, hitherto discoverable only by hardship and hazardous exploration, will be positively known. It is consid-' erod that wealth that will make the fabled riches: of Aladdin look insignificant lies underneath the soil. Some of it has already been tapped. Hundreds of millions have been dug from the ground in the very circumscribed areas already worked. Multiplied rewards await the day when certainty of locaI tion shall make the winning of untold values a matter of steady perseverance and determination. ' Geophysical prospecting 'is expected to bring about this certainty. Gold, !. silver, copper, and lead ore are yet to be discovered in Australia in areas that 1 have riot been toucned. One authority stated recently that Australia had been playing a game of blind man's bluff over hundreds and thousands of square ,miles in a hit-pr-miss fashion at tho cost of many lives and great treasure. It is difficult" to explain in popular terms the methods which have revolutionised prospecting in other parts of the world. Delicate instruments have to be devised, capable of being worked only by' trained experts, by which the secrets of the earth are able to be wrested from it. A marvellous instrument, known as the- Eotvos torsion "baliance, is used in the'examination of the flat, or moderately undulating areas, where large massive mineral deposits or oil pools, are likely to occur. It has been particularly, successful in oil-prdß-pocting1 in Persia, Burma, and in North America. The abolition of toilsome bore prospecting, where hope changes to- despair as the money dwindles, is certainly to be welcomed. The instrument is used for the first method, the gravito-metric, involving the measurement of small differences of the specific gravity of rocks in the area to be prospected. The instrument .talks a language which tells the scientists the secrets that lie beneath. In the case of country holding magnetic ores,. the magnetic method is used, whore the effoct on the delfcate mechanism is analogous to that which shifts tho needle of the compass. The third method, the electrical, is a postwar .development,,; Of these,' there are really several; dependent on the known fact that certain different deposits of oil, water, and minerals cause , slight differences in electrical conductivity to manifest themselves. The scientists read tho stories 'told by these differonces. . , The story of the decision to use geophysics in Australia is interesting. Mr. H. W. Gepp, of the Development »and Migration Commission, was commissioned to make inquiries in > England. He suggested that Britain should co-operate with Australia in testing the new methods. It was then that the Empire Marketing Board agreed to help in an exhaustive trial. It gave £10,000 for the first year of the trial and £6000 for the second on a £ for & basis' with, the Commonwealth., • Government. , Australian graduates are to be trained in the wo;rk, under ..the direction of Mr. Edge, and one more step on the road of progress will have been taken. Science once more is quietly leading Australia onward. .