f manures, 474-492.

Arabian coast, guano deposits on, 328.

Arable soil, absorptive power of, 98.

Arbrohlos Island guano, 309.

Arendt, experiments on oats by, 503.

Aristotelian doctrine of chemical elements, 4.

Artificial soil, 54.

Aruba phosphate, 308, 328, 379.

Ash, constituents of plants, 53-55;
of rye, phosphoric acid in, 204;
of wheat, phosphoric acid in, 204;
of farmyard manure, composition of, 287, 288.

Ashes, an adulterant of guano, 319;
mixed with manures, 532.

Asia, guano from, 298.

Asparagin, nitrification in, 182.

Atacama, nitrate of soda deposits at, 342.

Atmosphere, ammonia in, 48, 81;
relation of, to plants, 39.

Atwater on nitrogen in plants, 44.

Augite, 105.

Australia, guano from, 298;
virgin soils of, 133.

Avenine in oats, 503.

Aves guano, 309, 328;
phosphoric acid in, 330.

Bacilli, 94.

Bacon, Lord, on salt as a manure, 469.

Bacteria, in soil, 92;
different classes of, 93-96.

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

Ballestas, guano from, 302, 327;
nitrogen in, 329;
phosphoric acid in, 329.

Barilla, potash in, 420.

Barley, farmyard manure not suited for, 497;
fertilising ingredients removed from soil by, 485;
manurial constituents in, 282;
manuring of, 495, 498;
nitrogen removed in crop of, 145;
Norfolk experiments on, 497;
period of growth of, 495;
period of ripening of, 495;
Rothamsted experiments on growth of, 566;
soils suited for, 496;
uniform manuring of, 497.

Barley soils, amount of nitrates and nitrogen in, 158.

Barley-straw, composition of, 238;
manurial constituents in, 282.

Basalt, phosphoric acid in, 202, 210.

Bases fixed by soil, 58.

Basic ammonium phosphate in concretionary nodules, 328.

Basic process of steel-smelting, 400.

Basic silicates, 103.

Basic slag, 401-417;
after-effects of, 412;
application of, method of, 416
--rate of, 414;
compared with other manures, 410-414;
composition of, 404, 417;
Darmstadt experiments with, 410;
discovery of value of, 403;
manufacture of, 401;
preparation of, processes for, 406;
relative activity of, 411;
soils best suited for, 414;
solubility of, 408;
Wagner's experiments with, 408-413.

Bat guano, 320, 325;
nitrogen in, 325;
phosphoric acid in, 325.

Beans, fertilising ingredients removed fr