INDEX.

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 comparison of, when exposed to γ rays and to hard X rays, 184 of insulators, 209 of air in caves and cellars, 507 et seq. of air in closed vessels, 531 et seq. variation of, in closed vessels with pressure and nature of gas, 534 variation of, with temperature for air in closed vessels, 536 increase of, with time, in a closed vessel, 537
Conservation of radio-activity examples of, 469 et seq.
Cooke, H. L. penetrating rays from the earth, 520 number of ions per c.c. in closed vessels, 534 radio-activity from ordinary matter, 536
Cooke, W. T. and Ramsay radio-activity produced by radiations of radium, 472

538