ympathetic vibrations, 274-277.

Tallow, 105, 148.

Tartar, cream of, 229.

Telegraph, 322.
long distance, 327.
relay, 325.
sounder, 324.

Telephone, 350-351.

Temperature, 13-14.
as measurement of heat present, 27.
in detecting adulterants, 17.
in forging steel, 16.
in making sirups, 16.
measurement of, 14-15.

Thermometer, 14-17.
Centigrade, 15.
Fahrenheit, 15.

Tinder box, 47.

Transmission, of light, 145-147.
of sound, 267-271.

Tuning fork, 266, 273, 278, 290.

Turbine, steam, 183.
water, 178.

Turpentine, and grease, 226.
by distillation, 35.

Unleavened bread, 233.

Vacuum, sound in, 268.

Vapor, in atmosphere, 36-38.

Vaporization, heat of, 32.

Varnish, on candies, 253.

Vegetable matter, and coal, 30.
and gas, 30.
and oil, 30.

Veins, formation in rock, 72-73.

Velocity, of sound, 271-272.

Ventilation, 21-24, 54.
need of, 38.

Vibration, of strings, 286-290.
sympathetic, 274-277.

Viola, 295.

Violin, 295.

Violoncello, 295.

Vocal cords, 300.

Voice, 300.

Volt, 344.

Voltage, 345.

Voltaic cell, 306-308, 310.

Voltmeter, 344.

Volume, of a stream, 179-180.
relation of pressure of a gas, 95-96.

Washing powders, 224-226.
soda, 229.

Water, action in nature, 70-74.
amount used daily per person, 181.
and hydrogen, 79.
and oxygen, 79, 80.
as solvent, 70-71.
boiling, 77.
boiling point, 15.
composition, 79-80.
condensation, 33.
dams and reservoirs, 214-216.
density, 11.
distilled, 34, 77.
drinking, 75-77, 195-201.
electrolysis, 79-80.
evaporation, 33-34.
expansion, 9-10, 41-42.
filtration, 77.
freezing, 40-41.
hard, 225.
heat of fusion, 40.
impurities, 76-77.
in atmosphere, 36-38.
in food, 75.
in human body, 75.
in vegetables, 75.
influence on climate, 29, 40.
irrigation, 193-194.
minerals in, 70-71.
ocean, 265.
power, 176-180.
precipitates, 72, 73.
pressure, 208-211, 214-216.
purification, 77.
rain, 225.
running, value of, 178-180.
source of, 78.
steam, 32.
wave