INDEX 
Grier and Rutherford 
magnetic deviation of B rays of 
thorium, 96 
relative current due to a and B rays, 150 
nature of rays from Ur X, 294 
Hardy 
coagulation of globulin by radium 
rays, 175 
Hardy and Miss Willcock 
coloration of iodoform solutions by 
radium rays, 175 
Hardy and Anderson 
action of radium rays on the eye, 177 
Harms 
number of ions per c.c., in closed 
vessel, 376 
Haschek and Exner 
spectrum of radium, 17 
Heat 
rate of emission of, from radium, 158 
emission of, from radium at low 
temperatures, 159 
rate of emission of, after removal of 
the emanation, 162 
rate of emission of, by the emanation, 
162 
variation with time of heat emission 
of radium, and of its emanation, 162 
connection of heat emission with the 
radio-activity, 161 
source of heat energy, 163 
heating effect of the emanation, 247 
heating effect of emanation X, 278 
et seq. 
proportion of heating effect, due to 
radio-active products, 280 
total heat emission during life of 
radio-elements, 336 
heating of earth by 
matter, 344 
Heaviside 
apparent mass of moving charged 
body, 109 
Helium 
produced by radium and its emana- 
tion, 327 
amount of, from radium, 331 
origin of, 331 
Helmholtz and Richarz 
action of ions on steam jet, 44 
Hemptinne 
action of rays on spark, and electrode- 
less discharge, 171 
Henning 
resistance of radium solutions, 171 
effect of voltage on amount of ex- 
cited activity, 281 
Heydweiler 
loss of weight of radium, 336 
radio-active 
391 
Himstedt 
action of radium rays on selenium, 171 
Himstedt and Nagel 
action of radium rays on eye, 177 
Hofmann and Strauss 
radio-active lead, 26 
Hofmann and Zerban 
active substance from pitchblende, 25 
Huggins, Sir W. and Lady 
spectrum of phosphorescent light of 
radium bromide, 169 
Hydrogen 
production of, by radium rays, 176 
Induced radio-activity (see Excited 
radio-activity) 
Induction 
radio-active, 21 
meaning, and examples of, 289 
Insulators 
conduction of, under radium rays, 172 
Todoform 
coloration produced in, by radium 
rays, 175 
Ionization 
theory of, to explain conductivity of 
gases, 28 et seq. 
by collision, 36, 54 
variation of, with pressure of gas, 58 
et seq. 
variation of, with nature of gas, 62 
comparison of, produced by rays, 93, 
149 
total, produced by 1 gram radium, 154 
production of, in insulators, 172 
natural ionization of gases, 373 et seq. 
Ions 
in explanation of conductivity of gases, 
28 et seq. 
rate of recombination of, 37 et seq. 
mobility of, 39 et seq. 
difference between mobility of positive 
and negative, 42, 43 
condensation of water around, 43 e¢ 
seq. 
difference between positive and nega- 
tive, 46 
charges carried by, 47 
diffusion of, 48 et seq. 
charge on ion same as on hydrogen 
atom, 51 
number of, produced per c.c., 52 
size and nature of, 52 et seq. 
definition of, 52 et seq. 
production of, by collision, 36, 54 
velocity acquired by, between colli- 
sions, 55 
energy required to produce, 55 
comparative number of, produced in 
gases, 62 
