CONTENTS. 



PAGE 



Colourimeter Design. By H. Hartridge, M.D., Fellow of King's 



College, Cambridge. (One Fig. in text) 271 



The Natural History of the Island of Rodrigues. By H. J. Snell 

 (Eastern Telegraph Company) and W. H. T. Tams. (Communi- 

 cated by Professor Stanley Gardiner) 283 



Preliminary Note on the Life History of Lygocerus {Proctotrypidae), 

 hyperparasite of Aphidius. By Maud D. Haviland, Fellow of 

 Newnbam College. (Communicated by Mr H. H. Brindley) . 293 



Note on the solitary wasp, Crabro cephalotes. By Cecil Warburton, 



M.A., Christ's College 296 



Neon Lamps for Stroboscopic Work. By F. W. Aston, M.A., Trinity 

 College (D.Sc, Birmingham), Clerk-Maxwell Student of the Uni- 

 versity of Cambridge. (One Fig. in text) 300 



The pressure in a viscous liquid moving through a channel loith diverging 

 boundaries. By W. J. Harrison, M.A., Fellow of Clare College, 

 Cambridge. (One Fig. in text) 307 



The Efect of Ions on Ciliary Motion. By J. Gray, M.A., Fellow of 



King's College, Cambridge 313 



A Note on Photosynthesis and Hydrogen Ion Concentration. By J. T, ■ 



Saunders, M.A., Christ's College 315 



The distribution of intensity along the positive ray parabolas of atoms 

 and molecules of hydrogen and its possible explanation. By F. W. 

 Aston, M.A., Trinity College (D.Sc, Birmingham), Clerk-Maxwell 

 Student of the University of Cambridge. (Three Figs, in text) . 317 



Gravitation and Light. By Sir Joseph Larmor, St John's College, 



Lucasian Professor 324 



On a Micro-voltameter. By C. T. R. Wilson, M.A., Sidney Sussex 



College 345 



The self-oseillations of a Thermionic Valve. By R. Whiddington, M, A., 



St John's College 346 



Proceedings at the Meetings held duiing the Session 1918 — 1919 . 347 



Index to the Proceedings with references to the Transactions . . 350 



