INDEX 



311 



Osmotic pressure, 96 etseq,^ 105 

 Ostwald, 104 



Paschen, 249 



Pedigree of radium family, 196 



Periodic law, 212 ; table, 216 



Perrin, 142 



Persei, /S, 275 



Pfeffer, 94, 96, 97 



Phases, 8, 88 



Philosophical basis of physical 



science, 7, 11 et seq. 

 Phosphorescence and fluor- 

 escence, 136, 165, 172 

 Phosphorescence at low tem- 

 perature, 65 

 Phosphorus, 202 

 Photographs applied to astro- 

 physics, 266, 280 

 Physiology, 16, 93, 116, 181 

 Pictet, 45, 46 

 Picton, 117 

 Pitch-blende, 166 

 Planck, 2, 10, 105, 245, 246, 247, 

 260 



Platinum thermometer, 62, 74, 

 269 



Polarization of light, 222, 229 

 Polish, 90 



Polonium, 166, 195 



Porous plug experiment, 48 



Positive rays, 155 



Potassium, radio-activity of, 180 



Poynting, J. H., 295, 298 



Pressure of radiation, 293 etseq. 



Principe, 259 



Proton, 242 



Prout, 213 



Psycho-physics, 14, 17, 34 



Quantum Theory, 2, 10, 40, 

 231,245,251,260,280 



Radiation, 213, 223 et seq., 

 237 et seq., 265, 293, 297 ; 

 stellar, 303 



Radio-active deposits, 174, 179, 

 188 



Radio-activity, 5, 9, 164 et 

 seq.', analysis by means of, 

 167 



decay of, 175 ; curves, fig. 

 32, p. 178; fig. 33, p. 183; 

 H' 34, p. 189 

 energy of, 165, 186, 197 

 of ordinary materials, 180, 

 199, 286; of the earth 

 and atmosphere, 179, 180 

 Radium, idd etseq., 189 ; atomic 

 weight of, 194 ; life of, 194; 

 pedigree of, 196 

 Ramsay, Sir Wm., 55, 57, 191, 



282 

 Rankine, 58 

 Rayleigh, the late Lord, 55 



56 

 Rayleigh, Lord, 170, 179 



Regenerative process of lique- 

 faction, 50 



Relativity, 151, 253, 256; 

 principle of, 10, 17, 21, 28, 

 38 



Resonance, 263 



Reversal of spectral lines, 264, 

 273 



Richardson, O. W., 156 



Roberts-Austen, Sir W. C, 82, 

 205 



Rock salt, structure of, 141 



Rontgen, 137, 240 



Rontgen rays, 125, 137 etseq. 



Roozeboom, 80, 81, 88 



Rotation of sun, 272 



Rowland, 268 



Royds, 194 



Russell, Hon. Bertrand, 8 



