An asterisk (*) indicates use of one or more illustrations in connection with reference to which appended.

A	B	C	D	E	F	G	H	I	K	L	M
N	O	P	Q	R	S	T	U	V	W	Y	Z

• Acetylene, carbon and hydrogen in, 315.
• Acids, 351 ff.;
  • action of, on metals, 351-353*;
  • action of, on cloth, 354*;
  • action of, on nerves of taste, 354-355;
  • distinguished from bases by litmus test, 358-359;
  • neutralization of, by bases, 360-364.
• Action and reaction, law of, 77-81*.
• Adhesion, 39, 41-44;
  • cohesion, capillary attraction, and, 47.
• Air, cooling of, on expanding, 95-96;
  • liquid, 97;
  • heat carried by, by convection, 118-119;
  • absorption of light by, 169;
  • sound produced by vibrations of, 174-181*;
  • pitch due to rapidity of vibrations of, 186;
  • water vapor in, 275-280*;
  • a mixture and not a compound, 309;
  • part taken by, in making automobile go, 344;
  • limewater test for carbon dioxid in, 375.
• Air pressure, 10 ff., 14*;
  • height water is forced up by, in vacuum, 19;
  • high and low, 20, 282;
  • winds caused by, 20-21.
• Air pump, 14*, 15.
• Alcohol, boiling of, 112;
  • distilling, 113*-114.
• Alkali, 356;
  • in soap, 357-358.
• Alloys, definition of, 310.
• Alternating current, defined, 211-212.
• Alum crystals, experiment with, 265-266*.
• Aluminum, an element, 299.
• Alum in water, testing with litmus paper, 359.
• Amber, electricity produced by rubbing with silk, 196.
• Ammonia, example of a common base, 356;
  • action of, in cleaning cloth, 358;
  • litmus test of, 359;
  • neutralization of acid by, 363.
• Ampere, defined, 246.
• Analysis, chemical, 370-376.
• Aneroid barometer, 285*.
• Arc, the electric, 233-240*.
• Atoms, description of, 196;
  • electrons and, 197;
  • everything in the world made of, 310-311;
  • in molecules, 311.
• Aurora Borealis, cause of, 193.
• Automobile, reason for cranking, 210;
  • how made to go, 344-345.
• Automobile races, overcoming of centrifugal force in, 75*.
• Automobile tires, reason for wearing of, 80;
  • blow-outs of, 348.

• Baking powder, chemical change by solution shown by, 349-350;
  • elements of which made, 367-368.
• Baking soda, a common base, 356;
  • testing with litmus paper, 359;
  • neutralization of sour milk by, in cooking, 362;
  • carbon dioxid in, 366-367.
• Ball bearings, used to diminish friction, 54-55.
• Balloon, expansion of, 17-18, 109*;
  • reason for rising of, 26;
  • filling of, with hydrogen, 301-304*.
• Barometer, use of, 280-285*.
• Bases, substances called, 355-358;
  • litmus test for distinguishing from acids, 358-359;
  • neutralization of, by acids, 360-364.
• Batteries, electric, 203-205*;
  • different kinds of, 205*-207*;
  • general principle of all, 206.
• Bell, electric battery for ringing, 204-205*;
  • working of electric, 255*.
• Bending of light (refraction), 136-141*.
• Black, the absence of light, 164.
• Bleaching, process of, 326-327.
• Blow-out of tire, a real explosion, 348.
• Blue-flame heaters, 319.
• Blueness of sky, reason for, 169.
• Blueprints, making of, 330-331.
• Boiling and condensing, 107-115*.
• Borax bead test, 371*-372*.
• Brass, an alloy, 310.
• Bread making, chemical action in, 365.
• Breath, cause of visibility of, on cold days, 288, 289*.
• Bronze, an alloy, 310.
• Burning, explanation of, 308, 312-313.

• Calcium chlorid, 114.
• Camera, lens of, 143, 148;
  • human eye as a small, 151*-153;
  • explanation of, 327-332.
• Capillary attraction, 36*-40;
  • difference between adhesion, cohesion, and, 47.
• Carbon, in electric battery, 203-206;
  • resistance of, to electric current, 231;
  • an element, 293, 299;
  • one of chief elements in fuel, 315-316.
• Carbon dioxid, in seltzer siphon, 17;
  • produced by joining of carbon with oxygen, 315;
  • combining of water and, by plants, 332-333;
  • releasing of, in baking powder, 349-350;
  • bubbling of, in effervescence, 365-366;
  • in soda water, springs, and baking soda, 366-367;
  • limewater test for, 375-376.
• Carbonic acid gas, commercial name for pure carbon dioxid, 365-366.
• Cat's hairs, static electricity in, 201.
• Caustic soda, a common base, 356.
• Center of weight, 30-33*.
• Centrifugal force, 5, 72-74;
  • law of, 74-75.
• Charcoal, production of, 316.
• Charging water with carbon dioxid, 366.
• Chemical analysis, 370-376.
• Chemical change, and energy, 293 ff.;
  • burning (oxidation), 312-322;
  • caused by heat, 323-325;
  • caused by light, 326-335;
  • caused by electricity, 335-339;
  • energy released by, 340-341;
  • helped by solution, 349-351.
• Chemical equations, 297-299.
• Chlorine, an element, 299.
• Chlorophyll in plants, work of, 332.
• Cigar-box telegraph, construction of, 249*, 380-381*.
• Circuits, electric, 219-220*;
  • breaking and making, 220-221;
  • connecting in parallel, 221-223*;
  • grounded, 225-229*;
  • short, 240-245*.
• Cloth, action of acids on, 354*;
  • action of an alkali on, 356, 357*.
• Clouds, how formed, 277-278.
• Coal, carbon and hydrogen in, 315.
• Cohesion, 39, 44*-49.
• Cold, caused by expansion, 94;
  • is the absence of heat, 95, 120.
• Color, 161-172*.
• Comb, electricity produced by rubbing, 197-198.
• Compass, use of, 190-195*.
• Complete electric circuits, 219-224*.
• Compounds, how elements hide in, 300;
  • definition of, 308-309;
  • mixtures distinguished from, 309-310.
• Concave mirrors, 154*, 155*, 157;
  • magnification by, 157;
  • in reflecting telescopes, 157.
• Conduction, of heat, 116-118;
  • of electricity, 213-218.
• Conductors of electricity, good and poor, 213.
• Conduits for electric wires, 237.
• Conservation of energy, 57 ff.
• Convection, carrying of heat by, 118-119.
• Convex lens, 148-149*;
  • in microscope, 155-157*;
  • in telescope, 157.
• Cooling from expansion, 94-96.
• Coolness at night and in winter, 127-128.
• Copper, a good conductor of electricity, 215;
  • an element, 299;
  • nickel plating of, 336-339*;
  • etching of, with acid, 352*-353.
• Copper nitrate, salt called, 353.
• Cream, separating from milk, by centrifugal force, 75-76.
• Crystals, formation of, 265-268.
• Cylinder of engine, 344*.

• Dead Sea, reason for salt in, 104-105*.
• Decay, a kind of oxidation, 313.
• Dew, 275;
  • how formed, 287.
• Dictaphone, working of, 175, 178, 179*.
• Diffusion, 268-274;
  • of light, 158-161.
• Direct-current electricity, 211-212.
• Distilling of liquids, 112-115*.
• Doorbell, electric battery for ringing, 204-205.
• "Down," meaning of word, 4.
• Drainpipe, cleaning of, with lye, 358.
• Dry-cell battery, 206*.
• Dust, reason for clinging to walls, 43-44.
• Dynamite, 343*;
  • making of, 347.
• Dynamo, how electric current is made to flow by, 207*-210*.

• Earth, magnetism of, 190-195.
• Easy circuit, a short circuit an, 244-245.
• Echoes, explanation of, 183-185.
• Effervescence, process of, 365;
  • generally due to freeing of carbon dioxid, 367*-368;
  • helped by stirring or shaking, 368.
• Elasticity, 82-86;
  • of form distinguished from elasticity of volume, 86-87.
• Electrical apparatus, 216-217*, 222-223*;
  • description of, 379-380.
• Electric arc, the, 233*-240.
• Electric battery, the, 203-206*.
• Electricity, magnetism and, 190 ff.;
  • static, 196-202;
  • negative and positive charges of, 198*-200;
  • action of, in thunderstorms, 200-201;
  • flowing, 203 ff.;
  • flowing of, in dynamo, 207-210;
  • alternating and direct-current, 211-212;
  • conduction of, 213*-218;
  • chemical change caused by, 335-339.
• Electric lamps, vacuums in, 12*, 317;
  • incandescent, 125;
  • gas-filled, 317.
• Electric motors, 256*-257*.
• Electrolysis apparatus, 294-295*.
• Electromagnets, 247-257*.
• Electrons, 193;
  • description of, 197;
  • number of, in negative and in positive charges, 198-200.
• Elements, defined, 293;
  • chemists' abbreviations of, 297-299;
  • list of common, 299-300;
  • hiding of, in compounds, 300-301.
• Emulsion, defined, 261;
  • difference between solution and, 263.
• Energy released by chemical change, 340-341.
• Engine, working of cylinder and piston of, 344*.
• Ether, carrying of heat and light by, 124-125;
  • light as waves of, 163-164.
• Ether waves, 124-125, 163-164.
• Evaporating dish, 101*.
• Evaporation, 100-106*;
  • part taken by, in formation of clouds, rain, and dew, 277.
• Expansion, caused by heat, 88-93;
  • cooling from, 94-96*.
• Expansion ball and ring experiment, 91*-92.
• Explosions, use of, 34 per, experiments with, 358-359.
• Litmus test, the, 358-359.
• Lye, a common base, 356;
  • experiment with, 356;
  • soap made from, 357;
  • used for clearing out drainpipe, 358;
  • neutralization of, by acids, 363.

• Machinery, oiling of, to decrease friction, 53-54.
• Magdeburg hemispheres, 15, 16*-17.
• Magnetism, 190 ff.
• Magneto, of automobile, 210, 211*;
  • of old-fashioned telephone, 210-211.
• Magnets, 190-195*.
• Magnification, 150-157;
  • by concave mirror, 157.
• Magnifying glass, convex lens in, 149;
  • operation of, 150-156*.
• Manganese dioxid, an essential in explosives, 347.
• Megaphone, working of, 184.
• Melting, freezing and, 96-99.
• Membrane, diffusion through a, 272.
• Mercury, cohesion of, 47-48*;
  • use of, in thermometer, 89*, 90-91;
  • an element, 299.
• Mercury-vapor lamps, 167-168*, 172.
• Metals, good conductors of heat, 118;
  • good conductors of electricity, 215;
  • as elements, 310;
  • plating of, 336-339*;
  • action of acids on, 351-353.
• Microscope, 88;
  • working of, 155-157*.
• Mirrors, concave, 154*, 155*, 157.
• Mixtures, distinguished from compounds, 309-310.
• Molecular attraction, 36 ff.
• Molecules, pull of, on each other, 46-47;
  • explanation of, 88-89;
  • heat defined as the motion of, 90;
  • action of, in evaporation, 102-103*;
  • action of, in boiling water, 107;
  • action of, in conduction of heat, 117;
  • action of, in radiation of heat and light, 125;
  • action of, in magnetizing, 194*-195;
  • made up of atoms, 196, 310;
  • mingling of, 259 ff.;
  • action of, in formation of clouds, rain, and dew, 277.
• Moon, cause of ring around, 131.
• Morse telegraph code, 253.
• Motion-picture machines, lenses of, 143, 148.
• Motor, the electric, 255-257*.
• Mountains, rainfall on, 286-287.
• Musical instruments, pitch of, 290-292;
• elements of, 294-297;
• a compound and not a mixture, 308;
• formed by burning fuel, 316;
• why fire is put out by, but not burning oil, 317;
• combining of carbon dioxid and, by plants, 332-333;
• rusting of iron by, 349;
• acids and bases turned to salt and, by combining, 361-362.

Wear, a result of friction, 53.

Weather, forecasting of, 282-285.

Weight, center of, 30-33*.

Wet battery, 204-205*.

White, a combination of all colors, 162.

Winds, cause of, 20-21.

Winter, reason for cold in, 127-128.

Wiring for arc lamps, 236-239.

Wood, poor conductor of heat, 118;

• carbon and hydrogen in, 315.

• Yardstick, experiment with, to show leverage, 59*-60.
• Yeast, action of, in bread making, 365.
• Yellow, in flames, 318.
• Yerkes Observatory, telescope of, 156*.

• Zinc, in electric battery, 203-206;
  • an element, 300;
  • used for driving hydrogen out of acid, 301, 304.

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