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 from active deposit of radium, 377 et seq.  significance of appearance of, only in last radio-active changes, 455   change of weight due to expulsion of, 473  Barium platinocyanide   phosphorescence of, under radium rays, 203   change of colour due to radium rays, 205  Barkla   polarization of X rays, 80  Barnes and Rutherford   heating effect of radium emanation, 421, 429   connection of heating effect with radio-activity, 421   heating effect of active deposit, 425   heating effect of γ rays, 429   heating effect of emanation, 431   division of heating effect among active products, 433  Bary   phosphorescence under radium rays, 202  Baskerville   activity of thorium, 29   phosphorescence of kunzite under radium rays, 203  Baskerville and Kunz   phosphorescence of substances under radium rays, 204  Beattie, Smolan and Kelvin   discharging power of uranium rays, 7  Becquerel   rays from calcium sulphide, 4   rays from uranium, 5 et seq.   permanence of uranium rays, 6   discharging power of uranium rays, 6   magnetic deflection of radium rays by photographic method, 114 et seq.   curvature of radium rays in a magnetic field, 115 et seq.   complexity of radium rays, 116 et seq.   electrostatic deflection of β rays of radium, 124 et seq.   value of e/m for β rays of radium, 126 et seq.   magnetic deviation of α rays of radium and polonium, 145   trajectory of rays of radium in magnetic field, 148   scintillations due to cleavage of crystals, 160   γ rays from radium, 179   secondary rays produced by active substances, 187   phosphorescence produced by radium rays, 201   conductivity of paraffin under radium radiation, 210   effect of temperature on uranium rays, 210   chemical action of radium rays, 214   removal of activity from uranium by precipitation with barium, 219   theory of radio-activity, 438  Bemont et M. et Mme Curie   discovery of radium, 13  Berndt   spectrum of polonium, 23  Blanc   thorium in sediments from hot springs, 514  Blythswood, Lord and Allen, H. S.   radium emanation in Bath springs, 513  Bödlander and Runge   evolution of gases from radium, 215  Boltwood   origin of radium, 460   amount of radium in minerals, 460   proportionality of uranium and radium in minerals, 461   production of lead by uranium, 484   radium emanation in spring water, 514   method of standardization of amount of emanation in waters, 514  Boys   rate of dissipation of charge, 531  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