March pt/i, iprj.] PROCEEDINGS. 



xvn 



Ordinary Meeting, March 9th, 191 5. 



The President, Mr. Francis Nicholson, F.Z.S., 

 in the Chair. 



A vote of thanks was accorded the donors of the books 

 upon the table. Amongst these were : " The South Wales 

 Tornado of October 27, 1913" by H. Billett (Geophysical 

 Memoirs, No. 11) (Fol., London, 19 14), presented by the 

 Meteorological Office, London ; and " Rapporten van den 

 Oudheidkundigen Dienst in Nederlandsch-Indi'c, IQIJ V (8vo, 

 Batavia, etc., 19 14), presented by the Bataviaasch Genootschap 

 van Kunsten en Wetenschappen. 



Sir Ernest Rutherford showed fine crystals of the radio- 

 active mineral, autunite, which had been obtained from South 

 Australia. Comparatively large deposits of this ore had been 

 found by Dr. Mawson in this province. 



He also demonstrated the magnetic properties of some man- 

 ganese steels, kindly forwarded by Sir Robert Hadfield. By 

 suitable treatment, part of the same specimen of iron was non- 

 magnetic and part strongly magnetic. Such experiments illustrate 

 in a striking way the great variations produced in the magnetic 

 properties of iron by physical treatment. 



Professor Sir Ernest Rutherford, M.A., D.Sc, F.R.S., 

 read a paper entitled "Origin of the Spectra given by 

 Beta- and Gamma- rays of Radium" 



An account was given of recent experiments of Sir Ernest 

 Rutherford and Dr. Andrade to determine the wave length of the 

 very penetrating gamma rays which are emitted from radium. 

 The spectrum of the gamma rays was obtained by a photo- 

 graphic method by reflecting the rays from a thin slip of rock 

 salt. The radioactive source consisted of a fine glass tube 

 containing a large quantity of radium emanation. Special pre- 

 cautions were necessary to get rid of the effect of the penetrating 



