CONTENTS. 



PAGE 



On a configuration of ticenti/seven hyper-planes in four-dimen3io7ial 



spaces. By Professor W. Burnside 71 



Note on some double fiuorides of sodium. By W. A. R. Wilks. 



(Conmmnicated by Dr Fenton) 76 



An experiment on ionisation with y rays. By L. Yegard. (Com- 



nnmicated by Professor Sir J. J. Thomson) . . . . 78 

 The absorption spectra of solid tetramethylpicene and of its solutions. 



By J. E. Purvis and Miss A. Homer 82 



The absorption spectra of concentrated and diluted solutions of chlorophyll. 



By J. E. Purvis. ' (Plates I— III) 85 



The absorption spectrct of mesitylene and tricMoromesitylcnc. By J. E. 



Purvis 89 



On a so-called '■^ sexvxd" method of forming spores in Bacteria. By 



C. C. DOBELL 91 



On the alleged iurliwnce of lecithin upon the determination of sex in 



rabbits. By E. C. PuNNETT 92 



A coloured thio-o.valate. By H. 0. Jones and H. S. Tasker . . 94 

 Obscrrations on the changes in. the Common Shore-crab caused by 



Sacculina. By F. A. Potts. (One fig. in Text) ... 96 



On the secondary R&ntgen radiation from air and ethyl bromide. By 



J. A. Crowther. (One tig. iu Text) 101 



^4 string electrometer. By T. H. Laby. (Five figs, in Text) . . 106 



Interference fringes with feeble light. By G. I. Taylor. (Communicated 



by Professor Sir J. J. Thomson) .114 



On the parametric representation of the coordinates of points on a cubic 



surface in space of four dimensions. By H. W. Richmond . , 116 

 The study of discontinuous phenomena. By Normax Campbell . . 117 

 On the nature of anthocyanin. By Miss M. Wheldale. (Communi- 

 cated by Professor Bateson) 137 



The nature of the ionisation produced in a gas by y rays. By R. D. 



Ivleeman. (Communicated by Professor Sir J. J. Thomson.) 



(Tln-ee figs, in Text) . . .169 



jyotc on an abnormcd- pair of appendages in Lithobius. By T,. DON- 



c ASTER. (Two figs, in Text) .178 



On the migration of the theeacl-rells of Mwrisia. (Preliminary note.) 



By C. L. BouLENGER 180 



Action of Urethane on Esters of Organic Acids and JIustard Oils. By 



S. Ruhemaxx and J. G. Priestley 181 



Homologues of furfural. By Dr Fenton and F. Robinson . . . 182 



