CONTENTS OF VOL. XXI. SIXTH SERIES. V 



Page 

 Messrs. H. Donaldson and G. Stead on the Problem of 



Uniform Rotation treated on the Principle of Relativity . . 319 

 Dr. R. D. Kleeman on Relations between the Density, 



Temperature, and Pressure of Substances 325 



Dr. W. F. Gr. Swann on the Problem of the Uniform Rotation 

 of a Circular Cylinder in its Connexion with the Principle 



of Relativity 342 



Messrs. J. D. Fry and A . M. Tyndall on the Value of the 



Pitot Constant 348 



Mr. E. C. Snow on Restricted Lines and Planes of Closest 



Fit to Systems of Points in any Number of Dimensions . . 367 

 Mr. Thomas Ralph Merton on a Method of Calibrating Fine 



Capillary Tubes 386 



Notices respecting New Books : — 



Mme. P. Curie's Traite de Radioactivite 390 



L. Barbillion and G. Ferroux's Les Compteurs electriques 

 a Courants continus et a Courants alternatifs ; A. Tur- 

 pain's Notions fondamentales sur la Telegraphie ; 



A. Turpain's Telephonie 391 



Proceedings of the Geological Society : — 



Mr. A. R. Horwood on the Orm-in of the British Trias . 392 



NUMBER CXXIV.— APRIL. 



Mr. A. LI. Hughes on the Ultra -Violet Light from the 

 Mercury Arc : 393 



Profs. 0. W. Richardson and H. L. Cooke on the Heat liberated 

 during the Absorption of Electrons by Different Metals . . 404 



Prof. Carl Barus : Interferometry with the Aid of a Grating. 41 1 



Dr. F. R. Sharpe and Mr. A. J. Lotka : A Problem in Age- 

 Distribution 435 



Dr. J. W. Nicholson on the Damping of the Vibrations of a 

 Dielectric Sphere, and the Radiation from a Vibrating 

 Electron 438 



Mr. J. Crosby Chapman on Homogeneous Rontgen Radiation 

 from Vapours 446 



Mr, F. W. Jordan on the Direct Measurement of the Peltier 

 Effect 454 



Dr. Gwilym Owen and Mr. Harold Pealing on Condensation 

 Nuclei produced by the Action of Light on Iodine Vapour. 465 



Mr, A. B. Meservey : Investigation of the Potentials required 

 to produce Discharges in Gases at Low Pressures 479 



Mr. R. Rossi on the Pressure Displacement of Spectral Lines. 499 



Mr. Norman Campbell : The Common Sense of Relativity . . 502 



Mr. A. E. Oxley on Apparatus for the Production of Circularly 

 Polarized Light 517 



