VI CONTENTS OF VOL. XXIV. SIXTH SERIES. 



Page 

 Dr. IT. Greiger and Prof. E. Butherford : Photographic Regis- 

 tration of a. Particles 618 



Mr. Gr. H. Livens on the Influence of the Physical Conditions 



of a Substance on its Absorption of Light 623 



Mr. S. A. Shorter on the Elasticity of Liquid Films and 



the Foaming of Solutions 629 



Mr. Louis B. Smyth on the Supply of Vadium Emanation 



from the Soil to the Atmosphere. (Plate XIV.) 632 



Miss May S. Leslie : A Comparison of the Coefficients of Dif- 

 fusion of Thorium and Actinium Emanations, with a Note 



on their Periods of Transformation 637 



Dr. H. G-eiger and Mr. J. M. Nuttall: The Ranges of the 



ct particles from the Thorium and Actinium Products .... 647 

 Miss Mary Taylor on the Emission of Sound by a Source on 



the Axis of a Cylindrical Tube . . i • 655 



The Earl of Berkeley on a Euler for Drawing Curves (564 



Sir J. J. Thomson : Multiply-charged Atoms. (Plate XV.). ■ 665 

 Prof. R. W. Wood : Resonance Spectra of Iodine by Multi- 

 plex Excitation. (Plates XVL-XlX.) 673 



Dr. R. A. Houstoun on the Deduction of Thermodynamical 



Relations 693 



Prof. J. Joly on the Radioactivity of Terrestrial Surface 



Materials 694 



Notices respecting New Books : — 



Prof. R. W. Wood's Physical Optics 705 



Dr. A. E. IT. Tutton's Crystallography and Practical 



Crystal Measurement 706 



Intelligence and Miscellaneous Articles : — 



Note on the Diffusion of Alkali Salt Vapours and on 

 the Measurement of the Velocity of Flames, by A. 



Becker . 707 



■ - 



NUxMBER CXLIIL— NOVEMBER. 



Dr. S. R. Milner on the Current-Potential Curves of the . v 

 Oscillating Spark and the Mechanism of Spark Conduction. 

 (Plate XX.) 709 



Prof. Alois F. Kovarik on Recoil Atoms in Ionized Air .... 722 



Prof. Edwin II. Barton and Mi\ Walter B. Kilby on Dust 

 Figures produced by Electric Sparks. (Plates XXI. & 

 XXII.) 72S 



Prof. O. W. Richardson on the Electron Theory of Thermo- 

 electric and Thermionic Effects <37 



Mr. Herbert E. Ives : Studies in the Photometry of Lights of 

 Different Colours. — III. Distortions in Spectral Luminosity 

 Curves produced by Variations in the Character of the 

 Comparison Standard and of the Surroundings of the 

 Photometric Field 744 



Lord Rayleigh on some Iridescent Films 75 L 



