CONTENTS. 



PAGE. 



Selective absorption of substances in the earth's crust: Prof. 



E. H. L. ScHWARZ, A.R.C.S., F.G.S i8i 



Uranium ores 185 



Notes on investigations on some South African tobaccos: 



M. LUNDIE 186 



Wireless forecasting to ships at sea 191 



Truth among the pragmatists : Rev. S. R. Welch, B.A., D.D., 



Ph.D .. 192 



New higher oxides of nitrogen 198 



The occurrence and distribution of manganese in the Western 



Districts of the Cape Province. W. Versfeld, B.A., B.Sc. 199 



Mineral industry in Rhodesia . . . .^ 202 



Agricultural education : R. W. Thornton 203 



Mars by colour photography 208 



Grape seed oil 208 



Modern chemistry 209 



Transactions of Societies 212 



New Books 212 



