781 



ifiU 



I N D E X. 



"Waves, light-, on extremely long 

 emitted by the quartz mercury 

 lamp, 689.' 



AVave-motion, on the potential and 

 kinetic energies of, 177. 



■ trains, on the stability of free, 



773. 



Wilson (Prof. II. A.) on the velocity 

 of the ions of alkali salt vapours 

 in flames, 711 ; on the number of 

 electrons in the atom, 718. 



Wilson (Dr. W.) on the discharge 

 of positive electricity from hot 

 bodies, 634. 



Wilson (W.) on the effect of tempe- 

 rature on the absorption-coefficient 

 of iron for y rav3, 532. 



Wireless telegraphy, on the bending 

 of electric waves in, 65. 



Wood (Prof. R. W.) on the focal 

 isolation of long heat-waves, 249 ; 

 on the resonance spectra of iodine, 

 261 ; on the transformation of a 

 resonance spectrum into a band- 

 spectrum by presence of helium, 

 265 ; on the destruction of the 

 fluorescence of iodine and bromine 

 vapour by other gases, 309 ; on 

 the influence upon the fluorescence 

 of iodine and mercury of gases 

 with different affinities for elec- 

 trons, 314. 



X-radiation, on the energy of scat- 

 tered, 648. 



X rays, on the distribution of second- 

 ary, 270 ; on an apparent soft- 

 ening of, in transmission through 

 matter, 659. 



END OF THE TWENTY-FIRST VOLUME. 



Printed by Taylok and Fwancis, Eed Lion Court, Fleet Street. 



