INDEX.

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, 448 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

550