Abney, Sir Wm., on sensitisers, 210.
Abundance of life, numerical, 98-100.
Adaptation and aggressiveness of the organism, 80.
Additive law, the, with reference to alpha rays, 220.
Age of Earth, comparison of denudative and radioactive methods of
finding, 23-29.
Aletsch glacier, 286.
Allen, Grant, on colour of Alpine plants, 104.
Allen, H. Stanley, on photo-electricity, 203.
Alpha rays, nature of, 214; velocity of, 214; effects of, on
gases, 214; range of, in air, 215; visualised, 218; ionisation
curve of, 216; number of, from one gram of radium, 237; number of
ions made by, 237.
Alpine flowers, intensity of colour of, 102.
Alps, history of, 141; Tertiary denudation of, 148; depth of
sedimentary covering of, 148; evidence of high pressures and
temperatures in, 149; recent theories of formation of, 150 _et
seq._; upheaval of, 147; age of, 147; volcanic phenomena
attending elevation of, 147.
Andes, trough parallel to, 123; not volcanic in origin, 118.
Angle of friction on ice, 261-265, 281-283; on glass, 261-265.
Animate systems, dynamic conditions of, 67; and transfer of
energy, 71; and old age, 72; mechanical imitation of, 76, 77.
Animate and inanimate systems compared, 73-75.
Appalachian range, formation of, 120.
Arrhenius, on elevation of continents, 17.
Aryan Era of India, 136.
Asteroids, probable origin of, 175; discovery of, 175; dimensions
of, 176; orbits of, 176; Mars' moons derived from, 177.