I 



THE 



SOUTH AFRICAN JOURNAL 

 OF SCIENCE: 



COMPRISING THE REPORT OF THE 



SOUTH AFRICAN ASSOCIATION 



FOR THE 



ADVANCEMENT OF SCIE^l 



r. 



19 16. ju 



MARITZBURG. 



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OFFICERS : 1916-1917. 



PRESIDENT. 

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



VICE-PRESIDENTS. 



A. H. Reid, F.R.I.B.A., F.R.San.I. Prof. E. H. L. Schwarz, A.R.C.S., F.G.S. 



Professor W. N. Roseveare, M.A, H. E. Wood, M.Sc, F.R.Met.S. 



HON. GENERAL SECRETARIES. 

 C. F. JuRiTz, M.A., D.Sc, F.I.C., Agricultural Chemical Research Laboratory, Capetown. 

 J. A. FooTE, F.G.S. , F.E.I.S., Commercial High School, Plein Street, Johannesburg. 



HON. GENERAL TREASURER. 

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



ASSISTANT GENERAL SECRETARY. 



H. Tucker-, Cape of Good Hope Savings Bank Buildings, St. George's Street, Capetown. 



P.O. Box 1497. (Telegraphic Address : " Scientific") 



EDITOR OF TRANSACTIONS. 

 Dr. C. F. Juritz. 



VOJL. Xlll. APRIL 1917. NO. 9. 



CAPE TOWN, 



PUBLISHED BY THE ASSOCIATION. 



1917. [Price 2s. 



