INDEX.

Aschkinass and Caspari action of radium rays on microbes, 216
Atmosphere excited activity from, 501 et seq. radio-activity of, due to emanations, 504 diffusion of emanations into, from the earth, 507 effect of temperature, pressure, &c. on radio-activity of, 517 et seq. presence of very penetrating radiation in, 520 comparison of radio-activity of, with radio-elements, 521 et seq. amount of radium emanation in, 524 et seq. ionization of, due to radium emanation, 526
Atom number of per c.c., 54 disintegration of, 234 et seq. complex nature of, 235 changing atoms, 444 et seq. possible causes of disintegration of, 486 evolution of, 496
Atomic weight of radium by chemical methods, 17 from spectroscopic evidence, 18 emanations, 273 of radio-elements and connection with radio-activity, 445
β rays discovery of, 113 magnetic deflection of, 114 complexity of, 116 examination by the electrical method, 118 effect of, on a fluorescent screen, 119 charge carried by the, 120 et seq. electrostatic deviation of, 124 velocity of, and value of e/m for, 126 variation of e/m with velocity of, 127 et seq. distribution of velocity amongst β particles, 131 absorption of, 134 et seq. variation of absorption with density, 136 et seq. number of β particles stopped by matter, 137 et seq. variation of intensity of, with thickness of layer, 140 secondary β rays, 189 et seq. relative ionization produced by α and β rays, 196 relative energy emitted in form of α and β rays, 196 et seq. phosphorescent action of, 201 et seq. physical action produced by, 207 et seq. chemical action of, 213 physiological action of, 216 from Ur X, 347 from active deposit of radium, 377 et seq. significance of appearance of, only in last radio-active changes, 455 change of weight due to expulsion of, 473
Barium platinocyanide phosphorescence of, under radium rays, 203 change of colour due to radium rays, 205
Barkla polarization of X rays, 80
Barnes and Rutherford heating effect of radium emanation, 421, 429 connection of heating effect with radio-activity, 421 heating effect of active deposit, 425 heating effect of γ rays, 429 heating effect of emanation, 431 division of heating effect among active products, 433
Bary phosphorescence under radium rays, 202
Baskerville activity of thorium, 29 phosphorescence of kunzite under radium rays, 203

535