199-206;
effect of, on the river system, 205;
fresh-water, 145;
formed from caverns, 202;
great, changing their outlets, 205;
of extinct volcanoes, 203;
temporary features of the land, 203;
volcanic, 203.

Lands,
great, relatively unchangeable, 96;
table, 91;
movements resulting in change of coast line, 351, 352;
shape of the seas and, 83, 84;
accounting for the changes in the attitude of the, 95;
and water, divisions of, 84;
dry, surface of, 85;
general statement as to the division of the, 83, 84;
surface, shape of the, 85;
triangular forms of great, 90.

Latitudes, horse, troublesome to mariners, 104.

Laplace and nebular hypothesis, 34.

Lava, 266-268, 270, 271, 292, 293, 295, 296, 303, 304;
flow of, invading a forest, 268;
from Vesuvius, 293;
of 1669, 295, 296;
temperature of, 295, 296;
incipient, 304;
outbreaks of, 292, 303;
stream eaves, 292, 293.

Law, natural,
Aristotle and, 3;
of gravitation, 4;
of the conservation of energy, 23.

Leaves, radiation of, 160.

Length of days affected by tidal action, 131.

Level surfaces, 91.

Life, organic, evolution of, 15, 16.

Light, belief of the ancients regarding, 42.

Lightning, 24, 164-168;
noise from, 166;
proceeding from the earth to the clouds, 165;
protection of buildings from, 165;
stroke, wearing-out effect of, 165.

Limestones, 353, 357, 358, 360, 364;
formation of, 357, 360.

Lisbon, earthquake of, 1755, 368, 369.

Lowell, Mr. Percival, observations on Venus, 64.

Lunar mountains near the Gulf of Iris, 397.

Mackerel sky, 35.

Mallet, Mr. Charles, and the study of earthquakes, 382, 383.

Man as an inventor of tools, 10.

Mangroves, 340;
diagram showing mode of growth, 340;
marshes of, 339.

Map of glaciers and moraines near Mont Blanc, 217;
of Ipswich marshes, 338.

Mapping with contour lines, 27.

Maps,
desirable, for the study of celestial geography, 77;
geographic sketch, 26, 27.

Marching sands jeopardizing agriculture, 123.

Marine animals, sustenance of, 361-363;
deposits, 325-327, 349, 356;
marshes, 336-340;
waves caused by earthquakes, 387.

Mars, 65-67, 84, 97;