* O' 



CONTENTS OF VOL. L. 



(FIFTH SEEIES). 





NtJMBEE CCCIL— JULY 1900. 



Page 

 Mr. B. L. Wills on the Effects of Temperature on the 



Magnetic Properties oE Iron and Alloys of Iron 1 



Mr. J. B. Tayler on the Heat of Formation of Alloys ...... 37 



Dr. Charles Davison on Scales of Seismic Intensity 44 



Prof. H. Nagaoka on the Elastic Constants of Bocks and the 



Velocity of Seismic Waves ........ 53 



Mr. James J. Guest on the Strength of Ductile Materials 



under Combined Stress ................».; 69 



Prof. John Trowbridge on the Production of the a?-Kays by a 



Battery Current i 132 



Lord Bayleigh on Approximately Simple Waves .......... 135 



Mr. B. Beattie on the Spark-Length of an Induction-Coil . . 139 

 Prof. B. W. Wood on Photography of Sound-waves, and the 

 Kinematographic Demonstration of the Evolutions of 



Beflected Wave-fronts 148 



Prof. Karl Pearson on the Criterion that a given System of 

 Deviations from the Probable in the Case of a Correlated 

 System of Variables is such that it can be reasonably 



supposed to have arisen from Bandom Sampling 157 



Notices respecting New Books : — 



Jacques Boyer's Histoire des Mathematiques ........ 176 



Eilhard Wiedemann and Hermann Ebert's Pbysikal- 



isches Praktikum 177 



Dr. O. E. Meyer's Kinetic Theory of Gases 177 



Proceedings of the Geological Society : — 



Mr. John Parkinson on the Bocks of the South-eastern 

 Coast of Jersey, and on the Bocks of La Saline (North 

 Jersey) 179-180 



