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
Clouds
formation of, by condensation of water round ions, 46 et seq.
difference between positive and negative ions in formation of, 49
Collie and Ramsay
spectrum of emanation, 292
Collision
ionization by, 39, 57
number of ions produced by β rays per cm. of path, 434
total number of ions produced by collisions of α particles, 434
Coloration
of crystals of radiferous barium, 15
of bunsen flame by radium, 15
of glass by radium rays, 213
of rock-salt, fluor-spar and potassium sulphate by radium rays, 213
Concentration
of excited activity on negative electrode, 297
activity of radium independent of, 466
Condensation
of water round the ions, 46 et seq.
of emanations, 277
experimental illustration of, 279
temperature of, 280
difference between point of, for emanations of thorium and radium, 283
from air sucked up from the earth, 510
Conductivity
of gases exposed to radiations, 31 et seq.
variation of, with pressure, 61 et seq.
variation of, with nature of gas, 64
comparison of, for gases exposed to α, β, and γ rays, 64
Page:Radio-activity.djvu/584
This page needs to be proofread.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/28/Radio-activity.djvu/page584-1024px-Radio-activity.djvu.jpg)