;
from shale-works, 354;
manure for cereals, 356;
most easily nitrifiable manure, 191;
production of, 151, 358;
properties of, 355;
source of nitrogen, 149;
sources of, 353, 354, 358;
sulphocyanate of ammonia in, 355.

Sulphate of lime a fixer, 246.

Sulphate of magnesia, an adulterant of guano, 319;
as a fixer, 246.

Sulphate of potash, application of, 422
--rate of, 423;
compared with muriate, 421;
sources of, 218, 420.

Sulphuretted hydrogen from farmyard manure, 258.

Sulphuric acid, action of, on bones, 382
--on guano, 311
--on tricalcic phosphate, 398;
in ash of plants, 54;
as a fixer, 245, 285;
necessary for plant-growth, 55;
superphosphate manufactured with, 384, 388.

Superphosphate, 382-400;
action of, 392-395
--sometimes unfavourable, 395;
application of, 395
--rate of, 397;
composition of, 391;
discovery of, 382;
hastens early growth, 394;
high-class, 392;
low-class, 392;
manufacture of, 383-385
--phosphates suitable for, 384;
medium-class, 391;
production of, 382;
reversion in, 389, 399, 400
--causes of, 389, 390;
reverted in soil, 392.

Surprise Island guano, 328.

Swan Island guano, 328.

Swedes, fertilising ingredients removed from soil by, 485;
manurial constituents in, 282;
manuring of, 514.

Swine-dung, alkalies in, 226;
composition of, 227;
nitrogen in, 226;
phosphoric acid in, 226;
water in, 226.

Swine-urine, alkalies in, 230;
composition of, 231;
nitrogen in, 230;
phosphoric acid in, 230;
water in, 230.

Sydney Island guano, 309.

Syenite, 106;
phosphoric acid in, 202, 211.

Sylvin, potash in, 220.

_Symbiosis_, 44.

Tamarugal, Pampa de, nitrate deposit in, 340.

Tarapaca, nitrate deposits in, 340.

Temperature necessary for nitrification, 52, 175.

Tetracalcic phosphate, 387;
occurrence of, 387, 405;
solubility of, 387.

Thaer on application of farmyard manure, 275.

Thiocyanates, nitrification in, 182.

Thomas-Gilchrist process of steel-smelting, 402.

Thomas-slag. See Basic slag.

Tillage increases number of plants, 86.

Timor Island guano, 309.

Tobacco, potash in, 217.

Torrefied horn, 426.

Torrefied leather, 428.

Tortola guano, 309.

Trachyte, phosphoric acid in, 202, 211.

Transpiration, by elm-tree, 71;
by oak-tree, 71.

Tree