INDEX.

Curie and Dewar production of helium by radium, 479
Curie, P. and Laborde heat emission of radium, 419 origin of heat from radium, 440 radium emanation in waters of hot springs, 514
Current through gases, 31 et seq. variation of, with distance between the plates, 59 et seq. variation of, with pressure of gas, 61 et seq. variation of, with nature of gas, 64 measurement of, by galvanometer, 84 measurement of, by electroscope, 85 et seq. measurement of, by electrometer, 90 et seq. measurement of, by quartz piezo-électrique, 105
Dadourian presence of thorium emanation in the earth, 512
Danne on deposit of radium not containing uranium, 465
Danne et Curie diffusion of radio-active emanation, 272 decay of excited activity from radium, 309 decay curves of radium and equation, 309 occlusion of radium emanation in solids, 310 changes in radium, 381 effect of temperature on active deposit, 390
Danysz action of radium rays on skin, 216
Darwin, G. H. age of sun, 492
Debierne actinium, 21 emanation from actinium, 249 decay of excited activity from actinium, 311 effect of magnetic field on activity excited from actinium, 324 barium made active by actinium, 417
Debierne and Curie evolution of gas from radium, 215 active gases evolved from radium, 251 phosphorescence produced by radium emanation, 252 distribution of luminosity, 252 rate of production of emanation independent of pressure, 266 effect of pressure on amount of excited activity, 266, 317

540