CONTENTS OF VOL. IX. SIXTH SERIES. V 



Page 



Dr. AY. Marshall Walls's Index of Spectra, Appendix O. 386 

 Dr. S. Czapski's Grundziige der Theorie der Optischen 



Instrumente nacfa Abbe 386 



Lieut. -Col. E. Aries's La Statique Chimique 3S7 



Dr. L. F. Gruttmann's Percentage Tables for Elementary 



Analysis • • • 388 



A. VerneuiPs Memoire sur la Reproduction Artificielle 



du Rubis par Eusion 388 



Proceedings of the Geological Society : — 



Dr. C. Davison on the Leicester Earthquakes of August 

 4th. 1893, and June 21st, 1904, on the Derby Earth- 

 quakes of July 3rd, 1904, and on Twin- Earthquakes . 388 



Mr. C. V. Bellamy on the Geology of Cyprus 390 



Mr. AY. G. Fearnsides on the Geology of Arenig Eawr 

 and Aloel Llvnfnan . . . 392 



NUMBER LIL— APRIL. 



Prof. J. H. Poyntiug on Radiation Pressure 393 



Dr. O. W. Eichardson on the Discharge of Electricity from 



Hot Platinum in Phosphorus Vapour 407 



Air. C. A. Bell on the Determination of Young's Alodulus 



(Adiabatic) for Glass 413 



Air. R. Hargreaves on Radiation and Electromagnetic Theory. 



II. ^Eolotropic Potential 425 



Dr. C. Y. Drysdale on the Curvature Alethod of Teaching 



Optics 467 



Prof. Y. Bjerknes on Maxwell's Stress Theory 491 



Lord Rayleigh on the Pressure of Gases and the Equation 



of Yirial 494 



Prof. A. A. Alichelson on a Reciprocal Relation in Diffraction. 506 

 Air. S. R. Cook on the Escape of Gases from Atmospheres. . 508 



Dr. G. Johnstone Stoney's Reply 510 



Air. P. Phillips on the Slow Stretch in Indiarubber, Glass, 



and Aletal AYires when subjected to a Constant Pull .... 513 

 Air. X. R. Campbell on the Radiation from Ordinary- Alaterials. 



(Plate YII.) 531 



Mr. X. R. Campbell on Radioactivity and Chemical Change.. 545 

 Air. A. AYood on Spontaneous Ionization of Air in Closed 



Yessels and its Causes 550 



Dr. G. Johnstone Stonev on Flat-Wavelet Resolution. — 



Part IL1 ' 577 



Air. B. B. Boltwood on the Origin of Radium 599 



Dr. X. Hehl on the Dimensions of the Cathode Images . . . 614 



