Page:Radio-activity.djvu/597

  connection with radio-lead, 413

Radium F
  variation of activity due to, 398
  effect of temperature on, 401
  separation of, on bismuth plate, 402
  connection with active deposit, 403
  variation of activity of, over long periods of time, 407
  presence in old radium, 409
  effect of, on activity of old radium, 409
  presence in pitchblende, 410
  connection with radio-tellurium, 411
  connection with polonium, 411, 412
  connection with radio-lead, 413

Rain
  radio-activity of, 505
  decay of activity of, 506

Ramsay, Sir W.
  amount of helium in thorianite, 486

Ramsay and Collie
  spectrum of emanation, 292

Ramsay and Cooke
  radio-activity produced by radiation from radium, 472

Ramsay and Soddy
  evolution of gas from radium, 215
  production of hydrogen and oxygen from radium, 215
  chemical nature of the emanation, 268
  gaseous nature of the emanation, 268
  volume of emanation, and change with time, 289
  helium from radium emanation, 291
  amount of helium produced by radium, 480

Ramsay and Travers
  amount of helium in fergusonite, 486

Rayless changes
  discussion of, 454, 552

Re, F.
  theory of radio-activity, 441

Recombination
  of ions, 40 et seq. constant of, 42 Recovery of activity of thorium after removal of Th X, 221 of activity of uranium after removal of Ur X, 223 significance of law of, 224 effect of conditions on rate of, 232 of activity of radium after removal of emanation, 372 of heating effect of radium, 423 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, 256 Richarz and von Helmholtz action of ions on steam jet, 47 Richarz and Schenck theory of radio-activity, 441 Rossignol and Gimingham decay of thorium emanation, 242 Runge spectrum of radium, 17 Runge and Bödlander evolution of gas from radium, 215 Runge and Precht spectrum of radium, 17 atomic weight of radium, 18 heating effect of radium, 420 Russel photographic action of substances, 83 Saake amount of emanation in air at high altitudes, 519 Salomonsen and Dreyer coloration of quartz by radium rays, 213 Saturation current meaning of, 33 et seq. application of, to measurements of radio-activity, 84 measurement of, 100 et seq.

Schenck
  radium emanation in springs, 513

Schenck and Richarz
  theory of radio-activity, 441

Schmidt
  discovery of radio-activity of thorium, 10

Schmidt and Wiedemann
  thermo-luminescence, 207

Schuster
  number of ions per c.c. in air of Manchester, 528
  radio-activity of matter, 529

Schweidler and Mache
  velocity of ions in air, 528

Schweidler and Meyer
  magnetic deviation of β rays by electrical method, 113
  absorption of β rays of radium by matter, 136
  activity proportional to amount of uranium, 195
  emanation from uranium, 348
  effect of crystallization on activity of uranium, 349
  rate of decay of radio-tellurium, 411