CONTENTS. 



PAGE 



Mr Harold A. Wilson, On the Hall Effect in Oases at Low Pressures . 249 



Mr P. V. Bevan, On some Phenomena connected with the Combination of 



Hydrogen and Chlorine under the influence of Light .... 264 



Mr L. Doncaster, Notes on the Development of Sagitta . . ' '. . 267 



Mr Henry M. Bernard, On the Unit of Classification for Systematic 



Biology . . 268 



Mr E. A. Newell Arber, Notes on the Binney Collection of Coal-Measure 

 Plants. Part ill. The Type- Specimens of Lyginodendron Old- 

 hamium (Binney) 281 



Mr 0. W. Bichardson, On the Negative Radiation from Hot Platinum . 286 



Mr J. A. McClelland, On the Action of Incandescent Metals in pro- 

 ducing Electric Conductivity in Cases . . . . . . 296 



