INDEX 



313 



Units, physical, 20, 35 

 Uranium, 165, 168, 182, 243 



Vacuum vessels, fig. i, p. 54 

 Valency, 117, 217 

 Valve, thermionic, 225 

 Van't Hoff, 97, 98, 105, 124 

 Velocity, of light, 252, 254, 255 ; 



of stars, 271 et seq. 

 Venus, temperature of the 



planet, 298 

 Viscosity of gases, 209 

 Vortex rings, 219, 233 



Wald, F.J 104 

 Waves, continuous, 226 

 Weight, 22, 26 

 Weyprecht, 'Ji 



Whetham, C. Dampier, 109, 



no, 118 

 Whitehead, A. N., 8, 259 

 Wilson, C. T. R., 132, 133, 144, 



147, 179, 206 

 Wilson, H. A., 131, 144, 155, 



157 

 V/ireless telegraphy, 158, 224 



Wireless telephony, 158, 224 



Wollaston, 263 



X-COMPOUNDS, 183, 188 

 X-Ray spectra, 141 

 X-rays, 240 



Young, 221 



Zeeman, 239, 278 

 Zeleny, 129 



