Vlll CONTENTS OF VOL. XXVII.— -SIXTH SERIES, 



Page 



M. L. Dunoyer and Prof. E. "W.Wood: Photometric Investi- 

 gation of the Superficial Resonance of Sodium Vapour. 

 (Plate XVII. figs. 8 & 9.) 1025 



Proceedings of the G-eological Society 1035 



Index , 1038 



PLATES. 



I. Illustrative of Prof. H. Nagaoka arid Mr. T. Takamine's 

 Paper on Crossed Spectra obtained by Combinations of 

 Different Interferometers, and their Applications to the 

 Measurement of Difference in Wave-lengths. 

 II. Illustrative of Mr. F. Soddy's Paper on the Existence of 

 Uranium Y. 



III. Illustrative of Mr. C. W. H. Foord's Paper on Air-Pressures 



used in Playing Reed Instruments. 



IV. Illustrative of Mr. W. J. Walker's Paper on the Relation- 



ship between the Viscosity, Density, and Temperature of 

 Salt Solutions. 

 V. Illustrative of Prof. H. Nagaoka and Mr. T. Takamine's 

 Paper on Anomalous Zeeman Effect in Satellites of 

 Mercury Lines. 

 VI. Illustrative of Dr. E. P. Kerschbaum's Paper on Interference 



Experiments in a Highly Rarefied Gas. 

 VII. Illustrative of Prof. R. W. Wood's Paper on the Separation 

 of Close Spectrum Lines for Monochromatic Illumination. 

 VIII. Illustrative of Prof. E. Taylor Jones's Paper on In- 

 duction-coil Potentials. 

 IX. Illustrative of Prof. A. W. Porter's Paper on the Formation 

 of Images by means of an Opaque Disk. 

 X. Illustrative of Mr. W. A. Jenkins's Paper on the Effect t of 

 a Magnetic Field on Metallic Resistance. 

 XI. Illustrative of Mr. H. Smith's Paper on the Spectroscopy 

 of the Electric Brush Discharge in Weak Acids and 

 Solutions. 

 XII. Illustrative of Sir E. Rutherford and Dr. E. N. da C. 

 Andrade's Paper on the Wave-Length of the Soft y Rays 

 from Radium B. 

 XIII. Illustrative of Dr. E. N. da C. Andrade's Paper on Regular 

 Surface Markings in Stretched Wires of Soft Metals. 

 XIV. & XV. Illustrative of Prof. R. W. Wood and Mr. G. A. 

 Hemsalech's Paper on the Fluorescence of Gases excited 

 by Ultra-Schumann Waves. 

 XVI. Illustrative of Dr. Manne Siegbahn's Paper on the Use of 

 the Telephone as an Oscillograph. 

 XVII. Illustrative of Prof. R. W. Wood and M. L. Dun oyer's 

 Papers on the Separate Excitation of the Centres of 

 Emission of the D Lines of Sodium, and on the Photo- 

 metric Investigation of the Superficial Resonance of 

 Sodium Vapour. 



