i 



DOUBLE ISSUE. 



THE 



SOUTH AFRICAN JOURNAL 

 OF SCIENCE: 



COMPRISING THE REPORT OF THE 



SOUTH AFRICAN ASSOCIATION 



FOR THE 



ADVANCEMENT OF SCIENCE. 



19 1 6. 

 MARITZBURG. 



OFFICERS : 1916-1917. 



PRESIDENT. 



Professor J. Orr, B.Sc, M.I.C.E. 



VICE-PRESIDExNTS 

 A. H. Reid, F.R.I.B.A., F.R.San I Prnf T7 w t c 



Professor W. N. Ros.v.«h, Ma! S' 1 Wol.'ulZ'^i^MJi^s''^' T-'^-S- 



HON. GENERAL SECRETARIES. 



HON. GENERAL TREASURER. 

 A. Walsh, P.O. Box 39, Capetown. 

 „ _ ASSISTANT GENERAL SECRETARY 



H. Tucker-. Cape of Good Hope Savings Bank Buildings St G^nrcr^'c c. . .-^ 



PO. Box 1497. (Telegraphic AdZsf :'" ScPen?,lc!'')^'''''' Capetown. 



EDITOR OF TRANSACTIONS. 

 Dr. C. F. JiTRiTz. 



VOL XIII. JUNE, 1917. NO. 10. 



CAPE TOWN, 



PUBLISHED BY THE ASSOCIATION. 



1917. 



[Prioe 2b. 



