208;
electrical action in the formation of rain and, 164;
flakes, formation of, 164;
red, 210;
slides, 210;
slides, phenomena of, 210, 211.

Soil,
alluvial, 321, 322;
atmospheric circulation of, 330, 331;
conditions leading to formation of, 313, 331;
continuous motion of the, 314;
covering of the earth, 343;
decay of the, 314, 315;
degradation of the, 344-348;
means for correcting, 346-348;
destruction in grain fields greater than the accumulation, 344;
developing on lava and ashes an interesting study, 343;
development of, in desert regions, 340;
effect of animals and plants on the, 317-320;
effect of earthquakes on the, 375;
fertility of the, distinguished from the coating, 344, 345;
fertility of, affected by rain, 327;
formation of, 314-321;
glacial, characteristics of, 324;
glaciated, 323, 324;
irrigation of the, 328-330;
local variation of, 327;
mineral, 321;
of arid regions fertile when subjected to irrigation, 341;
of dust or blown sand, 321;
of immediate derivation, 321, 322;
phenomena, 313;
processes of organic life in the, 315;
variation in, 321-331;
vegetation protecting the, 316, 317;
washing away of the, 346, 347;
winning, from the sea, 337;
work of ants on the, 318;
tiller, duty of the, 348.

Solar bodies,
general conditions of the, 63-71;
forces, action of, on the earth, 349;
system, 52, 56;
independent from the fixed stars system, 43;
original vapour of, 52, 53;
singular features of our, 68;
tide, 127.

Spheres,
difference in magnitude of, 51;
motions of the, 50, 51;
planetary, rotation of, on their axes, 56.

Spots, sun, 72.

Spouting horn, 141.

Springs, formation of small, 252.

Stalactitization, 256.

Stalagmites and stalactites on the roof and floor of a cavern, 257.

Stars as dark bodies in the heavens, 47;
discovery of Fraunhofer and others on, 23, 38;
double, 39;
and tidal action, 131;
earliest study of, 10;
fixed, important observations by the ancients of planets and, 43;
not isolated suns, 38, 39;
variation in the light of, 46;
limit of, seen by the naked eye, 11;
revolution of one star about