INDEX 
McLennan and Burton (cont.) 
radio-activity of ordinary materials, 
378 
emanation from ordinary matter, 379 
Mercury 
emanation from, 381 
Metabolon 
definition of, 324 
table of metabolons, 326 
radio-elements as metabolons, 332 
Meteorological conditions 
effect of, on radio-activity of atmo- 
sphere, 364 
Methods of measurement 
in radio-activity, 67 et seq. 
comparison of photographic and elec- 
trical, 67 et seq. 
description of electrical, 68 et seq. 
Meyer and Schweidler 
magnetic deviation of £ rays by elec- 
trical method, 95 
absorption of 8 rays of radium by 
matter, 113 
Mobility 
of ions, 39 et seq. 
Moisture 
effect of, on velocity of ions, 40, 42 
effect of, on emanating power, 214 
Molecule 
number of, in 1 ¢c.c. of hydrogen, 51 
molecular weight of radium emana- 
tion, 232 
molecular weight of thorium emana- 
tion, 234 
Molecular weight 
of radium emanation, 232 
of thorium emanation, 234 
Nagel and Himstedt 
action of radium rays on eye, 177 
Niewenglowski 
rays from sulphide of calcium, 4 
Number 
of molecules per c.c. of hydrogen, 51 
of ions produced in gas by active 
substances, 52 
of a particles emitted per gram of 
radium, 155 
of ions, produced per c.c. in closed 
vessels, 375 
Occlusion 
of emanation in thorium and radium, 
217 
of radium emanation by solids, 264 
Owens 
saturation current affected by dust, 
39 
effect of air currents on conductivity 
produced by thorium, 197 
393 
Owens (cont.) 
penetrating power of rays independent 
of compound, 132 
absorption of a rays varies directly as 
pressure of gas, 137 
Oxygen 
change into ozone, by radium rays, 174 
production of from radium solutions, 
176 
Ozone 
production of, by radium rays, 174 
Paraffin 
objection to as an insulator, 80 
conductivity of, under radium rays, 
173 
Patterson 
number of ions per c.c. in closed 
vessel, 376 
natural conductivity of air due to an 
easily absorbed radiation, 377 
effect of temperature on natural con- 
ductivity of air, 377 
Pegram 
electrolysis of thorium solutions, 277 
Penetrating power 
comparison of for a, 8 and y rays, 93 
variation in, of 8 rays, 98 et seq. 
comparison of, for a rays from radio- 
elements, 136 
variation of, with density for 6 rays, 
112 et seq. 
variation of, with density for a rays, 
137 
variation of, with density for y rays, 
143 
Penetrating radiation 
from the earth and atmosphere, 366 
Perrin 
negative charge of cathode rays, 102 
theory of radio-activity, 316 
Phosphorescence 
production of, by radium, 18 
production of, by radium and polon- 
ium rays, 166 
comparison of, produced by a and 8 
rays, 168 
of zine sulphide, 167 
of barium platino-cyanide, 168 
of willemite and kunzite, 168 
diminution of, with time, 168 
of radium compounds, 168 
spectrum of phosphorescent light of 
radium bromide, 169 
production of by heat (thermo-lumin- 
escence), 170 
produced by radium emanation in 
substances, 210, 227 
use of, to illustrate condensation of 
emanations, 237 
