Contents. 
V 
PAGE 
Note on Carbolic Acid as a Fixative foe, Histological Pre- 
parations. By C. Lawrence Herman ..... 169 
Note on a Sum op Products which Involves Symmetrically 
THE JVth Koots of 1. By Sir Thomas Muir, LL.D. . . 173 
New and Interesting South African Mosses. By H. N. Dixon, 
M.A., F.L.S. (With Plates XI and XII) 179 
Colour and Chemical Constitution : Part IX. — An Empirical 
Law of Change OF Colour. By James Moir, M.A.,D.Sc., F.I.C. 225 
Additional Note on the Resolvability of the Minors of a 
Compound Determinant. By Sir Thomas Muir, LL.D. . 229 
South African Microthyriacbae. By Ethel M. Doidge. (With 
Plates XIII— XIX) - . 235 
An Investigation of Ev^aporation over Free Surfaces of 
Water in Inland South Africa. By A. H. Wallis, C.E. 
(With Plate XX) 283 
Second Note on the Determinant of the Sum of Two 
CiRCULANT Matrices. By Sir Thomas Muir, LL.D. . . 293 
Magnetic Observations in Ehodesia. By the Rev. E. Gtoetz, 
S.J., M.A., F.R.S.S.A 297 
Colour and Chemical Constitution : Part X. — A Gteneral 
Numerical Solution of the Colour-Constitution Problem. 
By James Moir 303 
