Page:Radio-activity.djvu/593

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