303;
phosphoric acid in, 303.

Punta de Patillos, guano deposits at, 327.

Pyroxene, potash in, 220.

Quartz, evaporation of water from, 99.

Queensland, meat-meal guano from, 324.

Quercitan, experiments of, with roses, 8.

Rape-cake, capable of nitrification, 182;
manurial constituents in, 282.

Rape-seeds, imports of, 153.

Raza Island guano, 328;
phosphoric acid, 330.

Rectified guano, 311.

Relative trade values of phosphoric acid, 400.

Resin in guano, 305.

Retentive power of soils for water, 70-73.

Retrogression, nitrogen lost by, 142.

Reverted phosphates, 389-391;
determination of amount of, 391;
formation of, 387;
value of, 391.

Rhine, nitrates in waters of, 158.

Rice-meal, an adulterant of guano, 319;
manurial constituents of, 282.

Rocks, phosphoric acid in, 202.

Roots, influence of manures on composition of, 512;
manuring of, 510-522;
Norfolk experiments on, 513;
potash removed in, 217.

Rotation of crops, bearing of, on nitrification, 195.

Rotations, phosphoric acid in, 290;
potash removed in, 290.

Rothamsted, alternate wheat and bean rotation at, 524;
ammonia in rain at, 49;
barley experiments at, 566;
Broadbalk Field, alteration in composition of, 159
--manuring of, 159
--produce of wheat on, 159;
early experiments at, 33-36;
experiments, 560-572;
experiments with nitrate of soda at, 347;
experiments on nitrogen question at, 115
--mangel-wurzel, 568
--oats, 567
--potatoes at, 519
--value of nitrogen in farmyard manure, 271;
increase of nitrogen with manures at, 137, 513;
nitrates in barley-soils of, 158;
nitrates in cropped soils of, 130, 157;
nitrates in drainage of, 189;
nitrates in wheat-soils of, 131, 157;
nitrogen as nitrates in soils of, 129, 198;
nitrogen, decrease of, in soils, 159;
nitrogen in pasture at, 126;
pasture, increase of nitrogen in, 158;
retrogression of nitrogen at, 142;
soil, nature of, 561
--nitrogen in, at various depths, 156;
total amount of nitrogen lost at, 142;
turnip experiments at, 568;
unmanured fallow-land loses nitrogen by drainage at, 141;
wheat experiments at, 500, 562-565.

Roy on sources of plant-nitrogen, 42.

Rubidia in ash of plants, 55.

Ruffle, John, on superphosphate, 388.

Rye, manurial constituents in, 282.

Rye-grass suited for sewage,