Liebig's researches on, 23-32;
Liebig's services to, 31.

Agronomy, 56.

Air, ammonia in, 48, 118;
nitrates in, 118; nitrites in, 118;
nitrogen in, 116;
organic nitrogen in, 118.

Aitken, Dr, experiments with basic slag, 413
--with beans, 526, 530;
on germ-life in bones, 368;
on manuring of turnips, 515.

Albert, Heinrich, on solubility of basic slag, 409.

Albite, composition of, 103.

Albuminates, 460.

Albuminoids, in plants, 491;
of milk, nitrification in, 182;
phosphorus in, 205.

Algerian phosphate, 379.

Algoa Bay, guano deposits at, 328.

Alkalies, in cow-dung, 226, 227
--cow-urine, 230
--horse-dung, 226, 227
--horse-urine, 230
--pig-dung, 226, 227
--pig-urine, 230
--sheep-dung, 226, 227
--sheep-urine, 230.

Alkalinity necessary for nitrification, 172.

Alumina, in ash of plants, 55;
compounds, reversion caused by, 388, 400;
salts, in _salinas_, 335.

America, virgin soils of, 133.

American farming, 86.

Amides, 501.

Ammonia, absorbed by soil, 81;
amount dissolved in rain, 49;
amount in air, 48;
amount in soil, 127;
amount supplied to soil by rain, 155;
converted into nitrates in soil, 50;
converted into nitrous acid, 167;
fixed by soil, 58;
from decomposition of farmyard manure, 258;
from gas-works, 353;
lost in mixing manures, 533;
relation of, to plants, 48-50;
salts, most easily nitrifiable, 191;
salts of, in farmyard manure, 257;
sulphate of, 352-358;
value of, as a manure, 352.

Ammonium chloride in Chincha guano, 305.

Ammonium-magnesium phosphate in Chincha guano, 305.

Ammonium oxalate in concretionary nodules, 328.

Ammonium phosphate, in Chincha guano, 305;
in concretionary nodules, 328.

Ammonium sulphate, 352-358;
in Chincha guano, 305;
in concretionary nodules, 328.

Ammonium sulphocyanate, 355.

Ammonium urate in concretionary nodules, 328.

Amphibole, potash in, 220.

Analysis, of manures, 539-554;
of soils, value of, 90.

Anderson, Dr, analyses of minerals by, 103, 105-107;
on nitrogen in soil, 121, 124.

Angamos, guano from, 301, 329.

Animals, phosphoric acid in, 205;
potash in, 205;
solid excreta of, 224;
urine of, 228.

Apatite, Canadian, 201, 374;
composition of, 210;
most abundant form of phosphoric acid, 200;
varieties of, 200.

Application o