Gamma rays, nature of, 247: production of, by beta rays, 247; as
ionising agents, 249.
Geddes and Thomson, hunger and living matter, 71.
Geiger, range of alpha rays in air, 215; ionisation affected by
alpha rays in air, 216; on "scattering," 217; scattering and the
structure of the halo, 232.
Geikie, Sir A., uniformity in geological history, 15.
Geosynclines, 119; association with earthquakes and volcanoes,
142; of the tethys, 142; radioactive heat in, due to sediments,
130; temperature effects due to lateral compression of, 131.
Glacial epoch, phenomena of, 287.
Glacier motion, cause of. 285.
Glossopteris and Gangamopteris flora, 136.
Gondwanaland, 136.
Gradient of temperature in Earth's surface crust, 126.