INDEX.

Bragg and Kleeman theory of absorption of α rays, 172 et seq. relation between ionization and absorption, 174 et seq. range of α rays in air, 174 four sets of α rays from radium, 174 et seq.
Bronson use of steady deflection method with an electrometer, 104 decay of thorium emanation, 242 decay of excited activity from actinium, 312
Brooks, Miss variation of excited activity from thorium for short exposures, 304 effect of dust on distribution of excited activity, 305 decay curves of excited activity of radium measured by α and β rays, 307 et seq. decay curves of excited activity from actinium, 312
Brooks and Rutherford absorption of α rays by matter, 161 comparison of absorption of α rays from radio-elements, 164 diffusion of radium emanation, 270 decay of excited activity from radium, 306
Bumstead presence of thorium emanation in atmosphere, 512
Bumstead and Wheeler diffusion of radium emanation, 273 emanation from surface water and the soil, 512, 522 identity of emanation from soil with radium emanation, 512, 522
Burton radium emanation in petroleum, 516
Burton and McLennan penetrating radiation from the earth, 520 radio-activity of ordinary materials, 537 emanation from ordinary matter, 538
Campbell radio-activity of ordinary materials, 540
Canal rays discovery of, 78 magnetic and electric deflection of, 78 value of e/m for, 78 similarity of, to α rays, 110
Capacity of electroscopes, 87 of electrometers, 94, 102 standards of, 102
Carbonic acid radio-activity of natural, 516
Caspari and Aschkinass action of radium rays on microbes, 216
Cathode rays discovery of, 73 magnetic and electric deflection of, 74 value of e/m for, 75 radiation of energy from, 79 comparison of, with β rays, 120 absorption of, by matter, 136, 137 see also β rays
Caves radio-active matter present in air of, 514 et seq. radio-activity of air of, due to emanation from the soil, 515
Changes (see Transformations)
Charge carried by the ions, 50 et seq. negative charge carried by β rays, 120 measurement of charge carried by β rays, 121 et seq. positive charge carried by α rays, 145 measurement of charge carried by α rays, 151 et seq.
Chemical nature of emanation, 267 of active deposit, 312
Chemical actions of radium rays production of ozone, 213 coloration of glass and rock-salt, 213 on phosphorus, 214 on iodoform, 214 on globulin, 214 evolution of hydrogen and oxygen, 215
Child potential gradient between electrodes, 65 variation of current with voltage for surface ionization, 66

537