Haimanta period of India, 135.
Halley, Edmund, finding age by saltness of ocean, 13.
Hallwachs, photo-electric activity and absorption, 207.
Haloes, pleochroic, finding age of rocks by, 21; due to uranium
and thorium families, 227; radii of, 227; over-exposed and
underexposed, 228; intimate structure of, 229 _et seq._;
artificial, 229; tubular, in mica, 230; extreme age of, 231;
effect of nucleus on structure of, 232; inference from spherical
form of, in crystals, 233; structure of, unaffected by cleavage,
235; origin of the name "pleochroic,"235; colouration due to
iron, 235; colouration not due to helium, 236; age Of, 236; slow
formation of, 237, 238; number of rays required to build, 237;
and age of the Earth, 238-241.
Hayden, H.H., geology of the Himalaya, 134, 138, 139.
Heat-tendency of the universe, 62.
Heat emission from the Earth's surface, 126; from average igneous
rock due to radioactivity, 126.
Helium and the alpha ray, 214, 222; colouration of halo not due
to, 236.
Hering, E., and physiological or unconscious memory, 111.
Herschel and Babbage theory of mountain building, 123.
Herschel, Sir W., on galaxy of milky way, 293.
Hertz, negative electrification discharged by light, 204.
Himalaya, geological history of, 134-139.
Hobbs, on association of earthquakes and geosynclines, 143.
Holmes, A., original lead in minerals, 20; age of Devonian, 21.
Horst concerned in Alpine _déferlement_, objections to, 156.
Hyperion, dimensions of, 177.