CONTENTS. 
Mr Harold A. Wilson, On the Hall Effect in Gases at Low Pressures . 
Mr P. V. Bevan, On some Phenomena connected with the Combination of 
Hydrogen and Chlorine under the influence of Light . 
Mr L. Doncaster, Notes on the Development of Sagitta .... 
Mr Henry M. Bernard, On the Unit of Classification for Systematic 
Biology 
Mr E. A. Newell Arber, Notes on the Binney Collection of Coal-Measure 
Plants. Part in. The Type- Specimens of Lyginodendron Old- 
hamium (Binney) 
Mr 0. W. Richardson, On the Negative Radiation from Hot Platinum . 
Mr J. A. McClelland, On the Action of Incandescent Metals in pro- 
ducing Electric Conductivity in Gases . . . . . . 
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