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