biological properties of, 142, 143.
chemical properties of, 142, 147.
most important properties of, 150.
physical properties of, 142.

Fertility of the soil, 150.
economizing the, 150.
maintaining the, 150.

Fertilizers, commercial, 68, 192.
analysis of, 203.
classification of, 171.
home mixing, 211.
how to know what kind is needed, 212.
importance of thorough mixing with the soil, 15.
manufactured, 202.
many brands, 202.
mixed, 202.
raw materials, 192.
sources of lime, 193, 200.
sources of nitrogen, 193.
sources of phosphoric acid, 193, 195.
sources of potash, 193, 199.
use of by farmer, 172, 192.
value of plant food in, 205.

Filament of stamen, 129.

Film water, 50.