fertility of, 65-108;
fineness of, 69-70;
gases in, 100;
hygroscopic power of, 75-76, 99;
improved by humus, 272;
influence of farmyard manure on, 475;
on nitrification, 180;
manures increase fertility of, 474;
nitrates in, amount of, 128-131;
nitrifying organisms in, 179;
distribution of, 179;
nitrogen absorbed by, 81, 82, 131;
nitrogen accumulates, 133;
nitrogen in, amount of, 120-128;
nitrogen least abundant of manurial ingredients in, 270;
nitrogen at various depths in, 156;
oxygen absorbed by, 81;
phosphoric acid in, 203
--condition of, in, 203
--occurrence of, in, 203;
peat, 123;
possesses power of fixing ammonia, 57;
potash in, 215
--condition of, in, 216;
potential fertility of, 549;
power of, for absorbing gases, 81;
relation of, to plant-roots, 84;
retention of plant-food by, 57;
retentive power of, for water, 70-73;
sewage purified by, 435;
shrinkage of, 74;
variation in absorbing powers of, 82;
varieties of, 67;
virgin, 133;
water in, most favourable amount of, 75;
water-logged, 179;
wheat, nitrates in, 157.

Soluble phosphate, 386.

Sombrero phosphate, 308, 328, 330, 379;
phosphoric acid in, 330.

Somme phosphate, 378.

Soot, 428;
application of, rate of, 429;
crops suited by, 429;
nitrogen in, 428.

South America, guano deposits in, 327;
meat-meal guano from, 324.

Starbuck Island guano, 309, 328;
phosphoric acid in, 330.

Stassfurt salts, 214;
potash in, 215, 420.

Stead and Ribsdale on formation of basic slag, 407.

Stoeckhardt, on composition of solid excreta, 226;
on composition of urine, 229.

Storer, Professor, on composition of birds' dung, 331;
on composition of leaves, 242;
on fish-guano, 323;
on nitrogen removed in milk, 147.

Straw, composition of, 238;
imports of, 153;
as litter, 236, 248;
mineral matter in, 238, 243;
nitrogen in, 237, 243;
variation in composition of, 237.

Subsoil, conditions favourable for nitrification in, 181.

Suffolk coprolites, 374.

Sugar-beet refuse, potash in, 219.

Sulphate of alumina, a precipitant of sewage, 437.

Sulphate of ammonia, 352-358;
ammonia in, 355;
application of, 356;
composition of, 355;
a concentrated nitrogenous manure, 356;
converted into nitrates, 356;
from gas-works, 353;
from iron-works, 355