i 4 



CONTENTS OF VOL. XLVL 



(FIFTH SEEIES). 



NUMBER CCLXXYIIL— JULY 1898. 



Page 



Dr. "William S. Day on a Comparison of Bowland's Thermo- 

 meters with the Paris Standard, and a Eeduction of his 

 Value of the Mechanical Equivalent of Heat to the Hydrogen 

 Scale 1 



Mr. J. A. McClelland on the Conductivity of the Hot G-ases 

 from Flames « 29 



Prof. E. A. Lehfeldt on the Properties of Liquid Mixtures. — 

 Part II 42 



Mr. Alfred Stausfield on some Improvements in the Boberts- 

 Austen Eecording Pyrometer, with Notes on Thermo-Elec- 

 tric Pyroinetry 59 



Lord Kelvin on Contact-Electricity of Metals 82 



Mr. John Zeleny on the Eatio of the Velocities of the Two 

 Ions produced in Gases by Eontgen Badiation ; and on 

 some Eelated Phenomena 120 



Prof. J. J. Thomson on the Mechanical Forces acting on a 

 Piece of Iron carrying an Electric Current 154 



Dr. G. Johnstone Stoney on Mr. Lewis Wright's Criticism of 

 Theories of Microscopic Vision 150 



Mr. E. W. Wood on Equilibrium- Figures formed by Floating 

 Magnets 162 



.Notices respecting New Books : — 



Messrs. S. AV. Stratton and E. A. Millikan's College 

 Course of Laboratory Experiments in G-eneral Physics. 165 



2 r* 



Dr. James Burgess's On the Definite Integral —-=- \ e~ t2 dt, 



VT Jo 

 with Extended Tables of Values 165 



