VALUABLE WORK

Evening Post, Volume CXXXIX, Issue 103, 3 May 1945, Page 8

VALUABLE WORK

AUSTRALIAN SCIENTIST

O.C. SYDNEY, April 24. Chief Australian geophysicist, Mr. J. M. Raynor, who will visit America shortly with the Director of the Commonwealth Minerals Resources Survey, Dr. H. G. Raggatt, has two great wartime achievements to his credit. Mr. Raynor searched for data on magnetic observations from old Japanese, Dutch, and British records, and made new observations which reduced all the information to a common basis. From this data maps were made, showing the difference between the magnetic north and true north at any point in Australia and the western Pacific almost to the shores of Japan. These maps were invaluable navigational aids to Australian and Allied forces. Mr. Raynor's other achievement was the use of ultra-violet light in the detection of minerals. It was known from overseas early in the war that scheelite, from which tungsten, a vital war metal, was made fluoresced under ultra-violet light. Fluorescence was the quality in minerals which enabled them, while remaining undetectable in rocks in daylight, or ordinary electric lieht to slow in brilliant colours under the ultra-violet light. When Mr. Raynor and his colleagues put a Piece of rock containing scheelite under the lamp the expected brilliant blue-grey or wattle-yellow glow did not appear. After experiments, Mr. Raynor found the ultra-violet light was not the right wave-length, devised a special lamp, and saw the scheelite glow. Portable ultra-violet lamps were taken to King Island, between Tasmania and the mainland, and helped scientists follow the trend of the biggest scheelite deposits in the world. ... , Mr Raynor's department has also been experimenting in the paddocks around Canberra with an apparatus for the detection of wooden land mines. This problem has taxed .scientific brains all over the world. It is no secret that metallic land mines which blow up Snks can be quickly detected by electrical inductive methods. But these do not work for mines made from wood, earthenware, or plastic materials The Canberra geophysicists have made an ingenious apparatus with which they are experimenting with sound waves. Once or twice, they think, they, were