PLATES. 



I. Illustrative of Prof. Barton and Miss Browning's Paper on 

 Triple Pendulums with Mutual Interaction and the Analogous 

 Electrical Circuits. 

 II. Illustrative of Prof. L. Vegard's Paper on Recent Results of 

 Northlight Investigations and the Nature of the Cosmic 

 Electric Rays. 

 III.- VI, Illustrative of Prof. K. Honda and Mr. S. Konno's Paper on the 

 Determination of the Coefficient of Normal Viscosity of 

 Metals. 

 VII. Illustrative of Dr. F. W. Aston's Paper on the Mass Spectra 

 of Chemical Elements. 

 VIII.-X. Illustrative of Mr. E. V. Appleton and Dr. Balth. van der Pol's 

 Paper on the Form of Free Triode Vibrations. 

 XI. Illustrative of Miss Marian Baxter's Paper on Dispersion of 

 Light by Potassium Vapour. 

 XII. Illustrative of Prof. W. D. Harkins's Paper on the Constitution 

 and Stability of Atom Nuclei. 



XIII. Illustrative of Mr. Yngve Bjornstahl's Paper on Magnetic 



Double Refraction of Gold Colloids. 



XIV. Illustrative of -Mr. A. Miiller's Paper on an X-Ray Bulb with 



a Liquid Mercury Anticathode, and on Wave-Length Mea- 

 surements of the L-Spectrum of Mercury. 

 XV. Illustrative, of Dr. F. W. Aston's Paper on the Mass Spectra 

 of the Alkali Metals. •, 



XVI. Illustrative of Dr. D. A. Keys's Paper on a Piezoelectric 



Method of Measuring Explosion Pressures. 

 XVII. Illustrative of Mr. G. H. Henderson's Paper on the Range and 

 Ionization of the * Particles from Radium C and Thorium C. 

 XVIII. & XIX. Illustrative of Mr. H. T. Jessop's Paper on Corau's 

 Method of Determining the Elastic Constants of Glass. 

 XX. Illustrative of Prof. Nihal Karan Sethi's Paper on the Dif- 

 fraction of Light by Cylinders and Spheres immersed in a 

 Medium of nearly equal Refractive Index. 

 XXI. & XXII. Illustrative of Prof. R. W. Wood's Paper on Hydrogen 

 Spectra from Long Vacuum Tubes. 

 XXIII. Illustrative of Mr. A. L. Narayan's Paper on Sounds of 



Splashes. 

 XXIV. Illustrative of Mr. F. Twyman's Paper on an Interferometer 



for Testiug Camera Lenses. 

 XXV. Illustrative of Prof. C. V. Raman and Mr. G. L. Datta's Paper 

 on Quetelet's Rings and other Allied Phenomena. 

 XXVI. Illustrative of Mr. G. P. Thomson's Paper on the Application 



of Anode Ravs to the Investigation of Isotopes. 

 XXVII. Illustrative of Drs. P. W. Forte, W. F. Meggers, and F. L. 

 Mohler's Paper on the Excitation of the Enhanced Spectrum 

 of Magnesium in a Low Voltage Arc. 



ERRATA. 



In 10th line from bottom, page 249 : — 



For A(„)=(l-£) - read \(u)= (l-'^ 



In 8th line from top, page 283— the last term should read — 5 instead of; 

 In 7th line from top, page 281— instead of M > M M read M a > M. n . 



w 



