THE 



SOUTH AFRICAN JOURNAL 

 OF SCIENCE: 



COMPRISING THE REPORT OF THE 



SOUTH AFRICAN ASSOCIATION 



FOR THE 



ADVANCEMENT OF SCIENCE. 

 1919. 



KINGWILLIAMSTOWN. 



OFFICERS : 1919-1920. 



PRESIDENT. 



1. B. Pole Evans, M.A., D.Sc. F.L.S. 



VICE-PRESIDENTS. 

 Prof. J. W. Bews, M.A., D.Sc. Prof R Lesitf ma p" c c 



|Prof. J. E. D^KKBEK, M.Sc.. Ph.D.. A.R.C.S. P^ot l tmU^sL^H, RCS 



HON. GENERAL SECRETARIES. 



HON. GENERAL TREASURER. 

 =>rof. C. E. Moss. M.A.. D.Sc F.L.S., F.RG S., South African School of Mines and 



Technology, Johannesburg. *^° 



ASSISTANT GENERAL SECRETARY 

 M. K. Carpenter, P,0. Box 6894. Johannesburg. (Telegraphic Address '•Science.') 



EDITOR OF TRANSACTIONS. 

 Dr. C. F. Juritz. 



'OL XVI. AUGUST, 1919. NO. I 



CAPETOWN, 

 PUBLISHED BY. THE ASSOCIATION. 



19^9 [Price 2b, 



