Part 51

Insect life in the higher Alps, 104, 105; destruction of, on the Alpine snows, 106.

Ionisation by alpha ray, density of, 221; importance in chemical actions, 250; in living cell, 250.

Ions, number of, produced by an alpha ray, 237.

Isostasy, 53; and preservation of continents, 53.

Ivy, inconspicuous blossoms of, 107; delay in ripening seed, 107.

Kant and Laplace, material hypothesis of, does not account for the past, 290.

Kelvin, Lord, experiment on effects of pressure on ice, 268-270.

Kleeman and Bragg. See Bragg.

Klopstock introduces skating into Germany, 273.

Lakes, cause of blue colour of, 55.

Land, movements of the, 53, 54.

Laukester, Ray, the soma and reproductive cells, 85.

Lapworth, structure of the Scottish Highlauds, 153.

Latent heat of water, 266.

Latent image, formed at low temperatures, 202; Bose's theory of, 203; photo-electric theory of, 204, 209 et seq.

Least action, law of, 66.

Lembert and Richards, atomic weight of lead, 27.

Length of life dependent on conditions of structural development, 93; dependent on rate of reproduction, 94.

Life-curves of organisms having different activities, 92.

Life, length of, 91.

Life waves of a cerial, 95; of Ausaeba, 87; of a species, 90.

Light, effects of, in discharging negative electrification, 204; chemical effects of, 205; experiment showing effect of, in discharging electrified body, 205.

Lindemann, Dr., duration of solar heat, 29.

Lowell, Percival, observations on Mars, 167 et seq.; map of Mars, reliability of, 198.

Lucretius, birth-time of the world, 1.

Lugeon, formation of the Prealpes, 171; sections in the Alps, 154.

Lyell, uniformity in geological history, 15.

Magee, relative areas of deposition and denudation, 16.