Makower
diffusion of radium emanation, 274
diffusion of thorium emanation, 276
Marckwald
preparation of radio-tellurium, 25
rate of decay of radio-tellurium, 411
Mass
apparent mass of electron, 71, 127
variation of mass of electron with speed, 127 et seq. of α particle, 147 et seq.
Materials
radio-activity of ordinary, 528, 536 et seq.
Matteucci
rate of dissipation of charge in closed vessels, 531
McClelland
absorption of γ rays, 181
secondary rays from β and γ rays from radium, 192
McClung
coefficient of recombination of ions, 41
conductivity of gases exposed to X rays, 64
ionization by α rays from radium C, 550
McClung and Rutherford
energy required to produce an ion, 58
variation of current with thickness of layer of uranium, 195
estimate of energy radiated from radio-elements, 418
radiation of energy from radium, 438
McLennan
absorption of cathode rays, 65
radio-activity of snow, 506
excited radio-activity at Niagara Falls, 519
McLennan and Burton
penetrating radiation from the earth, 520
radio-activity of ordinary materials, 537
emanation from ordinary matter, 538
Metabolon
definition of, 446
table of metabolons, 449
radio-elements as metabolons, 457
Meteorological conditions
effect of, on radio-activity of atmosphere, 517
Methods of measurement
in radio-activity, 82 et seq. comparison of photographic and electrical, 83 et seq. description of electrical, 84 et seq.
Meyer and Himstedt
production of helium by radium, 479
Meyer and Schweidler
magnetic deviation of β rays by electrical method, 113
absorption of β rays of radium by matter, 136
activity proportional to amount of uranium, 195
emanation from uranium, 348
effect of crystallization on activity of uranium, 349
rate of decay of radio-tellurium, 411
Minerals, radio-active
constant ratio of radium to uranium, 459 et seq. list of minerals, 461 age of, 485 composition of, 554 et seq.
Mobility
of ions, 43 et seq.
Moisture
effect of, on velocity of ions, 43, 45
effect of, on emanating power, 255
Molecule
number of, in 1 c.c. of hydrogen, 54
Molecular weight
of radium emanation, 273
of thorium emanation, 275
Nagel and Himstedt
action of radium rays on the eye, 217
Niewenglowski
rays from sulphide of calcium, 4
Nomenclature
of successive products, 328 et seq.
Number
of molecules per c.c. of hydrogen, 54
of ions produced in gas by active substances, 55
of β particles expelled from 1 gram of radium, 124
of α particles emitted per gram of radium, 155
of ions produced per c.c. in closed vessels, 534
Occlusion
of emanation in thorium and radium, 258
of radium emanation by solids, 310
Owens
saturation current affected by dust, 42
penetrating power of rays independent of compound, 164
absorption of α rays varies directly as the pressure of gas, 169
effect of air currents on conductivity produced by thorium, 238
Oxygen
change into ozone, by radium rays, 213
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