Page:Radio-activity.djvu/581

 INDEX.

The numbers refer to the pages.

α rays discovery of, 141 nature of, 141 magnetic deviation of, 142 et seq. electrostatic deviation of, 146 velocity of, 148 value of e/m for, 148 charge carried by, 151 et seq. number of α particles expelled from one gram of radium, 155 mass and energy of, 156 origin of, in atomic disintegration, 157 scintillations produced by, 158 et seq. absorption of, by matter, 161 et seq. increase of absorption with thickness of matter traversed, 163 relative absorption of α rays from radio-elements, 164 absorption of, by gases, 165 et seq. connection between absorption and density, 169 relation between ionization and absorption, 170 theory of absorption of, 170 et seq. range of ionization of, 172 et seq. complexity of α rays from radium, 174 et seq. effect of thickness of layer of radiating matter on emission of, 195 relative ionization produced by α and β rays, 196 et seq. phosphorescence by α rays, 202 et seq. connection of, with radio-active changes, 235, 444 et seq., 455 from the emanations, 263 emission of energy from radio-elements in form of α rays, 419 et seq. connection of heat emission of radium with α rays, 421 et seq. number of ions produced by an α particle, 433 absence of, in rayless changes, 454 emission from active products, 454 et seq. loss of weight due to expulsion of, 473 α particles consist of helium, 479 et seq. magnetic deflection of, from radium C, 543 velocity and e/m for, from radium C, 543 et seq. diminution of velocity of, in passing through matter, 545 diminution in velocity of, in passing through aluminium, 545 velocity of, when ionization ceases, 545 et seq. connection of phosphorescent, photographic, and ionization effects produced by, 546 et seq. energy required to produce an ion by α rays, 551

Abraham apparent mass of moving charged body, 71, 127

Absorption law of, in gases, 64 et seq. relative absorption of α, β and γ rays by matter, 111 connection between absorption and ionization, 134 et seq., 170 et seq. of β rays by solids, 134 et seq. connection between absorption and density for β rays, 137 of β rays in radio-active matter, 140 of α rays by solids, 161 et seq. of α rays in gases, 167, 170 et seq. connection between absorption and density for α rays, 169 theory of, 170 et seq. of γ rays by solids, 179 et seq. connection between absorption and density for γ rays, 181 of rays from the emanations, 263 of penetrating rays from the earth, 520, 540

Actinium methods of separation of, 20 et seq. properties of, 21 similarity to "emanating substance" of Giesel, 21