CONTENTS. 
South African Microthyriaceae. By Ethel M. Doidgb, (With 
Plates XIII-XIX) ......... 
An Investigation of Evaporation over Free Surfaces of Water in 
Inland South Africa. By A. H. Wallis, O.E. (With 
Plate XX) . . . 
Second Note on the Determinant of the Sum of Two Circulant 
Matrices. By Sir Thomas Muir, LL.D 
Magnetic Observations in Ehodesia. By the Eev. E. Goetz, 
S.J.. M.A., F.E.S.S.Afr. ........ 
PAOB 
236 
283 
293 
297 
Colour and Chemical Constitution. Part X. — A General Numerical 
Solution of the Colour-Constitution Problem. By James Moir. 303 
