vi Contents 



Mathematical Notes (continued); 



On a proof of the theorem of a double six of lines by projection from 

 four dimensions. (Three figs, in Text) . . . . . .133 



145 



147 



On transformations urith an absolute quadric .... 



On a set of transformations of rectangular axes. (One fig. in Text) 



On the generation of sets of four tetrahedra of which any tivo are 



mutually inscribed .......... 155 



On the reduction of homography to movement in three dimensions. (One 



fig. in Text) 158 



On the transformation of the equations of electrodynamics in the 

 Maxwell and in the Einstein for ms . . . . . . .166 



On the stability of periodic motions in general dynamics . . . 181 



On the stability of 7'otating liquid ellipsoids ...... 190 



On the general theory of the stability of rotating masses of liquid . . 198 



Sur le principe de Phragmen-Lindelijf Par Marcel Riesz. With Note 



by G. H. Hardy 205 



A note on the nature of the carriers of the Anode Rays. By G. P. 



Thomson, M.A., Fellow of Corpus Christi College .... 210 



Proceedings at the Meetings held during the Session 1919 — 1920 . . 212 



The Problem of Soaring Flight. By E. H. Hankin, M.A., Sc.D., late 

 Fellow of St John's College, Cambridge, Chemical Examiner to 

 Government, Agra, India. (Communicated by Mr H. H. Brindley.) 

 With an Introduction by F. Handlby Page, C.B.E., F.R.Aer.S. . 219 



Preliminary Note on the Superior Vena Ca,va of the Cat. By W. F. 



Lanchester, M. a., King's College, and A. G. Thacker . . . 228 



A Note on Vital Staining. By F. A. Potts, M.A., Trinity Hall. (One 



fig. in Text) 231 



Preliminary Note on a Cynipid hyperparasite of Aphides. By Maud D. 

 Haviland, Fellow of Newnham College. (Communicated by 

 Mr H. H. Brindley) 235 



A method of testing Triode Vacuum Tubes. By E. V. Appleton, M.A., 



St John's College. (Two figs, in Text) 239 



The Rotation of the Non-Spinning Gyrostat. By Sir George Greenhill 



and Dr G. T. Bennett 243 



On the representation of the simple group of order 660 as a groiop of linear 

 substitutions on 5 symbols. By Dr W. Burnside, Honorary Fellow 

 of Pembroke College ......... 247 



On the representation of algebraic numbers as a sum of four squares. By 



L. J. Mordell. (Communicated by Professor H. F. Baker) . . 250 



On a Gaussian Series of Six Elements. By L. J. Rogers. (Communicated 



by Professor G. H. Hardy) 257 



Note on Ramanujan^s trigonometrical function Cg(n), and certain series of 



arithmetical functions. By Professor G. H. Hardy .... 263 



On the distribution of primes. By H. Cramer, Stockholm. (Communicated 



by Professor G. H. Hardy) 272 



Note on the parity of the number which emimerates the partitions of a 



number. By Major P. A. MacMahon ' . 281 



Note on constant volume explosion experiments. By S. Lees, M.A., St 



John's College. (Two figs, in Text) 285 



