05-107.

Carbide, calcium, 152-153, 264.

Carbohydrates, 64-65, 149.

Carbolic acid, 152.
as disinfectant, 251.

Carbon, 56, 66.
in voltaic cells, 308.

Carbon dioxide, 53.
as fire extinguisher, 55-56.
commercial use, 55-56.
in baking soda, 228.
in fermentation, 234.
in health, 54.
in plants, 55.
preparation of, 55.
source of, 53.
test for, 228.

Catarrh, 259.

Caustic lime, 222..

Caustic potash, 222.

Caustic soda, 218, 222.
to make a salt, 227.

Caves and caverns, 71.

Cell, dry, 310.
gravity, 309-310.
voltaic, 306-308, 310.

Cells of human body, 63, 64, 66.

Centigrade thermometer, 15.

Central heating plant, 19.

Chalk, in making carbon dioxide, 55.

Charcoal as a filter, 57.
commercially, 57.
preparation, 57-58.

Chemical action, and electricity, 307, 315-317.
and light, 126, 127.

Chemistry, in daily life, 218, 219.

Chills, 38.

Chloride of lime, in bleaching, 240.
disinfectant, 251.

Chlorine, and hydrogen, 239.
effect upon human body, 239.
in bleaching, 238-240.
influence of light upon, 126.
presence in salt, 227.

Circuit, electric, 321.
local, in telegraph, 325-326.

City water supply, 206-212.

Clarinet, 297.

Cleaning of material, 226, 243.

Climate, influenced by presence of water, 29, 40.

Clover, nitrogen producers, 263.

Coal, 30.

Coal gas, 150, 151.
by-products, 152.

Coal oil, 149, 150.

Coal tar dyes, 152, 218, 245.

Cogwheels, 170.

Coil, current-bearing, 320.
magnetic field about, 331-333.

Coke, 152.

Cold storage, 97.

Color, 134-141.
and heat, 142, 143.
influenced by light, 137.
of opaque bodies, 136, 137.
of transparent bodies, 135, 136.

Color blindness, 140, 141.
designs in cloth, 248, 249.

Colors, compound, 138, 139.
essential, 139-140.
primary, 135.
simple, 138.
spectrum, 134-135.
variety in dyeing, 247, 248.

Combustion, heat of, 45.
spontaneous, 52.

Commutator, 335.

Compass, 328.

Compound colors, 138, 139.

Compound machine, 171.

Compound substances, 103.

Compression of air, 91, 92.
cause of heat,