VI CONTENTS OF VOL. XV. SIXTH SERIES. 
Page 
Mr. G. J. Elias on Anomalous Magnetic Rotatory Dispersion 
of Rare Earths. Remarks on Prof. R. W. Wood's recent 
paper 538 
Dr. Hans Geiger on the Irregularities in the Radiation from 
Radioactive Bodies 539 
Lord Rayleigh on Further Measurements of Wave-lengths, 
and Miscellaneous Notes on Fabry and Perot's Apparatus. 548 
Rev. P. J. Kirkby on the Positive Column in Oxygen 559 
Notices respecting New Books : — 
Prof. Carl Barus's Condensation of Vapor as induced 
by Nuclei and Ions 569 
H. S. Carslaw's Fourier's Series and Integrals 569 
J. J. van Laar's Sechs Vortrage iiber das Thermo- 
dynamische Potential 570 
The Scientific Papers of J. Willard Gibbs 570 
Prof. S. Newcomb's Compendium of Spherical Astronomy 570 
J. M. Pernter's Meteorologische Optik 571 
E. E. Fournier d'Albe's Two New Worlds 572 
Proceedings of the Geological Society : — 
Mr. W. Hill on a Deep Channel of Drift at Hitchin 
(Hertfordshire) 573 
Prof. G-. F. AVright : Chronology of the Glacial Epoch 
in North America 573 
Dr. H. C. Sorby on the Application of Quantitative 
Methods to the Study of the Structure and History 
of Rocks .... 574 
Messrs. C. Reid and H. Dewey on the Origin of the 
Pillow- Lava near Port Isaac in Cornwall 576 
Mr. R. M. Br} T done on the Subdivision of the Chalk at 
Trimmingham (Norfolk) 577 
Prof. T. G. Bonney on Antigorite and the Val Antigorio, 
with notes on other Serpentines containing that 
Mineral 578 
Mr. J. Y. Elsder, on the St, David's-Head "Rock- 
Series '"' (Pembrokeshire) 578 
Mr. W. B. Wright on the Two Earth-Movements of 
Colonsay 579 
Mr. H. Bury : Notes on the River Wey 579 
NUMBER LXXXIX.— MAY. 
Prof. R. W. Wood on the Resonance Spectra of Sodium 
Vapour. (Plates XVIII. & XIX.) 581 
Mr. Sidney Russ on the Distribution iu Electric Fields of 
the Active Deposits of Radium, Thorium, and Actinium . . 601 
Dr. R. A. Lehfeldt on the Electrochemical Equivalents of 
Oxygen and Hydrogen 614 
