Page:Radio-activity.djvu/601

  source of energy of radiation, 442 et seq. theory of radio-active change, 444 et seq. table of active products, 449 rate of change of, 458 life of, 458 radium probable product of, 459 et seq. amount of radium in, 460 et seq. amount of, in radio-active minerals, 461 growth of radium in, 463 conservation of radio-activity of, 469 total emission of energy from 1 gram of, 475 possible causes of disintegration of, 486 et seq.

Uranium X
  separation of, by Crookes, 219
  separation of, by Becquerel, 219
  decay of activity of, 223
  recovery of activity of, 223
  theory to explain production of, 224 et seq. material nature of, 226 explanation of decay of activity of, 229 changes in, 346 et seq. radiations from, 347 et seq. method of measurement of radiations from, 347 effect of crystallization on activity of, 349 diffusion of, 350 Velocity of ions in electric field, 42 et seq. difference between, of positive and negative ions, 43 et seq. of β particle or electron, 126 et seq. variation of mass of electron with, 127 of α particle, 148 of transmission of carriers of excited activity, 320 et seq. of ions in atmosphere, 528 Villard discovery of γ rays from radium, 179 alteration of X ray screen with time, 205 activity produced by cathode rays, 530 Vincenti and Levi Da Zara radium emanation in spring waters, 516 Voller variation of activity of radium with concentration, 467 Volume of radium emanation, calculation of, 289 decrease of, of radium emanation, 290 Walker, G. W. theory of electrometer, 90 Walkhoff action of radium rays on skin, 216 Wallstabe diffusion of radium emanation into liquids, 276 Water emanation from, 510 et seq. decay of activity of emanation from, 511 et seq.

Water-falls
  amount of excited activity produced at Niagara, 520
  electrification produced near, 520

Watts, Marshall
  atomic weight of radium, 18

Weichert
  velocity of cathode rays, 76

Weight
  loss of by radio-elements, 473
  attempts to measure loss of in radium, 474

Wheeler and Bumstead
  diffusion of radium emanation, 273
  emanation from surface water and the soil, 512, 522
  identity of emanation from soil with radium emanation, 512, 522

Whetham
  effect of valency of ion on colloidal solutions, 215
  production of radium from uranium, 463

Wiedemann
  thermo-luminescence, 207

Wiedemann and Schmidt
  thermo-luminescence, 207

Wien
  value of e/m for canal rays, 78
  positive charge of canal rays, 78
  amount of charge carried by β rays, 124

Willcock, Miss and Hardy
  coloration of iodoform solution by radium rays, 214

Willemite
  phosphorescence of, under radium rays, 203
  use of, to show condensation of emanation, 279

Willows and Peck
  action of radium rays on spark, 208