possible connection with radio-activity of thorium, 28
emanation from, 249
excited activity produced by, 311
effect of magnetic field on excited activity from, 324
separation of actinium X, 365
decay of actinium X, 365
source of actinium emanation, 365
analysis of active deposit of, 366
radiations from products of, 368
penetrating power of β and γ rays from, 368
products of, 369
table of products of, 449
possible origin of, 464
Actinium A
separation and period of, 367 et seq.
Actinium B
period of, 368
properties of, 368
Actinium X
separation and decay of, 364 et seq. production of emanation by, 365 Adams decay of activity of emanation from well water, 511 decay of excited activity from the emanation, 511 Age of radium, 457 of sun and earth, 492 et seq.
Allan, S. J.
increase with time of excited activity from atmosphere, 505
radio-activity of snow, 506
effect of conditions on decay of activity from air, 519, 523
Allan and Rutherford
decay of excited activity from the atmosphere, 503
ionization of air in closed vessels, 534
Allen, H. S. and Lord Blythswood
radium emanation in Bath springs, 513
Anderson and Hardy
action of radium rays on the eye, 217
Armstrong and Lowry
radio-activity and phosphorescence, 444
Arnold
rays from phosphorescent substances, 4
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
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