INDEX 
Radium (cont.) 
compounds of, 19 
nature of radiations from, 90 et seq. 
B rays from, 95 et seq. 
a rays from, 115 et seq. 
y rays from, 141 et seq. 
secondary rays from, 147 
heat emission of, 158 et seq. 
production of phosphorescence by, 
166 et seq. 
spectrum of phosphorescent light of, 
169 
physical actions of, 171 et seq. 
chemical actions of, 174 
physiological actions of, 176 
emanation from, 205 et seq. 
properties of emanation from, 205 et 
seq. 
chemical nature of emanation from, 
225 et seq. 
diffusion of emanation from, 228 et seq. 
condensation of emanation from, 236 
et seq. 
amount of emanation from, 246, 312 
heat emission of emanation from, 247, 
278 
excited radio-activity from, 251 et seq. 
decay of excited activity from, 261 
et seq. 
successive changes in emanation X of, 
272 
properties of emanation X of, 275 
heating effect due to products of, 278 
radio-active induction due to, 289 
connection of, with polonium, 291 
alteration of activity of, by removal 
of emanation, 300 
recovery of activity of, after removal 
of emanation, 301 
effect of escape of emanation on 
recovery of activity of, 302 
non-separable activity of, 302, 304 
radiations from active products of, 304 
division of activity amongst active 
products of, 306 
conservation of radio-activity of, 308 
determination of volume of emanation 
of and diminution with time, 313 
et seq. 
theories of radio-activity of, 316 
discussions of theories of radio-activity 
of, 320 
energy of radiations, not derived from 
external source, 321 
theory of radio-active change, 322 
list of active products of, 326 
polonium possible product of, 326 
production of helium from, 327 
helium disintegration product of, 327 
amount of helium from, 331 
395 
Radium (cont.) 
rate of change of, 332 
life of, 333 
origin of, 333 
possible production of, by uranium, 
334 
loss of weight of, 335 
experiments to determine loss of 
weight of, 336 
total emission of energy from 1 gram 
of, 336 
possible causes of disintegration of, 338 
amount of, to account for heat of sun, 
342 
possible connection of with heat of 
sun, 342 
probable amount of, in earth, 345 
possible connection with heat of earth, 
344 
Rain 
radio-activity of, 355 
decay of activity of, 356 
Ramsay and Soddy 
evolution of gas from radium, 176 
chemical nature of the emanation, 
227 
gaseous nature of the emanation, 227 
volume of emanation, and change 
with time, 313 
helium from radium emanation, 328 
Re, Filippo 
theory of radio-activity, 320 
Recombination 
of ions, 37 et seq. 
constant of, 39 
Recovery 
of heating effect of radium, 162 
of activity of thorium after removal 
of Th X, 181 
of activity of uranium after removal 
of Ur X, 182 
significance of law of, 185 
effect of conditions on rate of, 191 
of activity of radium, after removal 
of emanation, 301 
Reflection 
no evidence of direct reflection for 
uranium rays, 7 
diffuse reflection of rays, 7 
Refraction 
no evidence of, for uranium rays, 7 
Regeneration 
of emanating power, 215 
Richarz and von Helmholtz 
action of ions on steam jet, 44 
Runge 
spectrum of radium, 17 
Runge and Precht 
atomic weight of radium, 17 
heating effect of radium, 164 
