growth of wheat, 500.

Floated bones, 362, 365.

Florida phosphate, 378.

Fluorapatite, composition of, 210.

Food, consumed by pigs, 281;
dry matter of, voided in dung, 228;
percentage of, in excrements, 281.

Food-constituents, plant, necessary for nitrification, 170.

Forbes, David, on nitrate-fields of Chili, 334.

Forest-soils, absence of nitrification in, 193.

Fowl-dung, 320, 326;
analysis of, 331.

Fownes on phosphoric acid in rocks, 202.

Frankland, P. F., experiments on nitrification, 52, 167, 198.

Franklin, Benjamin, experiment of, with gypsum, 462.

Frey Bentos, meat-meal guano from, 324.

Galapagos Islands, guano deposits at, 327.

Garden earth, absorptive power of, 98;
ammonia in, 128.

Gas-liquor, ammonia in, 353.

Gas-works, ammonia from, 353, 358.

Gases, absorbed by soils, 81;
present in soil, 100.

Gazzeri on retention by soil of plant-food, 57.

Geese-dung, analysis of, 331.

Geic acid in humus, 47.

Gelatin, nitrification in, 182;
from bones, 364.

Germany, agricultural research in, 32;
bones imported from, 360;
manufacture of meat-meal guano in, 324.

Germination, influence of temperature on, 76;
oxygen necessary for, 81.

Gilbert, Sir J. Henry, on barley-manuring, 496;
on Liebig's mineral theory, 28;
on manuring of potatoes, 520;
Presidential address of, 61;
and see Lawes and Gilbert.

Glauber on artificial production of nitre, 164.

Glue, 364.

Glycin, assimilated by plants, 47.

Glycocoll, experiments with, 46.

Gneiss, 106;
phosphoric acid in, 207.

Grandeau, Professor, on forms of plant-food in soil, 107;
on loss of phosphoric acid, 207.

Granite, 105;
in guano, 303;
phosphoric acid in, 202, 211;
potash in, 214.

Grass, Bangor experiments on, 508;
effect of manure on, 505;
influence of farmyard manure on, 506;
manuring of, 504-510.

Gray, Asa, on transpiration by plants, 71.

Great Cayman guano, 379.

Green manures, 113.

Grouven on guano, 313.

Guanape Island guano, 302, 327;
nitrogen in, 329;
phosphoric acid in, 329.

Guanine, 304;
experiments with, 46.

Guano, 293-331;
action of, as a manure, 312;
adulteration of, 318;
application of, 315;
bat, 325;
composition of, 305, 329;
crust, 308;
deposits of the world, 327;
dissolved, 310;
equalised, 309;
fermentation of, 299;
fer