320 



INDEX 



Lightning, 241 



Light year, 17S 



Lilienthal, Otto, 310 



Limestone, 199 



Lime water, directions for making; 62 



Linen, 142 



Lister, Joseph, 220 



Living things, need of oxygen for, 24; 



properties of, 229 

 Loam, 209 

 Locomotive, early types of, 299; modern, 



301 ; electric, 301 

 Lodestone, 246 

 Longitude, meridians of, 192; and time, 



192 



Los Angeles water supply, 67-70 

 Low, 38, 40 ; usual pathway across country, 



44 



Lubrication, 146 

 Luminous, 98, 171 

 Lungs, in breathing, 11 



Macadam road, 291 ; cross section of, 293 

 Machines, simple, 156-161 ; efficiency of, 



161 



Maggot of fly, 223 

 Magnetic field, 245, 246 

 Magnetic lines of force, 245, 246 

 Magnetic pole, 245, 246 

 Magnetic substances, 246 

 Magneto, 248; of telephone, 249, 250 

 Magnets, 245 

 Malaria, 219, 223 

 Mammals, reproduction of, 231 

 Mammoth, 200 

 Mammoth Cave, 199 

 Man, improvement of, 234 

 Mantle rock, 198 



Manure, from animals, 212; green, 212 

 Marathon race, 265 

 Marble, 199 



Marconi, Guglielmo, 280 

 Mars, as a planet, 182 

 Mass, defined, 179 

 Matches, principles of, 138 

 Matter, structure of, 241 

 Maxwell, J. Clerk, 279 

 Mechanical, defined, 156 

 Mechanical advantage, of lever, 160; of 



pulley, 160 ; of inclined plane, 161 

 Mendel, Gregor, 234 

 Mercury, as a planet, 182 

 Mercury vapor lamp, 82 

 Meridians of longitude, 192 

 Metamorphic rock, 198 

 Meteor, 171; relation to comets, 184; 



showers, 184 



Meteorite, Cape York, 185 

 Meter, electric, 259 

 Metric system, 151 

 Michelson, A. A., 104 

 Milk, pasteurization of, 81, 85 ; as a perfect 



food, 84; composition of, 85 

 Milk supply, pure, 85 

 Milky Way, 175 

 Mixture, 21 

 Modulated wave, 282 

 Mohawk Trail, 293 

 Moisture in the air, 33-37 

 Molds, 87, 89 

 Molecule, 21, 129, 240 

 Monsoon winds, 4l 

 Montgolfier brothers, 308 

 Moon, apparent change in shape of, 186, 



188; surface of, 188; effect of on the 



earth, 189 



Morse, Samuel F. B., 268 

 Mosquito, 223, 224 

 Motor, electric. 257 

 Mt. Vesuvius, 205 



Mouth, digestion in, 93 



Moving pictures, 115 



Mulching of soil, 210 



Murdock, Wm., 101 



Music, in daily life, 17; different from 



noise, 18 



Musical instruments, 19, 20 

 Musical tones, 18, 19 



National Trail, 293 



Natural gas, 123 



Natural immunity, 218 



Neap tides, 190 



Nebula, 172; spiral, 176 



Nebular hypothesis, 196 



Nectar, 231 



Negative, photographic, 115 



Neon, 23 



Neptune, as a planet, 183 



Nerve cells, 77 



Newcomen's engine, 165 



Newton, Sir Isaac, 104, 150 



New York City water supply, 64 



Nimbus, 33, 35, 36 



Nitrates, for fertilizers, 212 



Nitrogen, 23 ; cycle of, 212 



Nodule, 207 



Noise, 17, 18 



Normandie, 304 



North star, 174 



Nucleus, 229 ; of the cell, 230 ; of the atom, 



240 

 Nutrient, 80 



Ocean cables, 270 



Ocean currents, 54 



Octave, 18 



Oersted, Hans Christian, 246 



Ohm, defined, 258 



Ohm, Geo. S., 261 



Ohm's law, 261 



Oil, as a fuel, 123 



Oil burner, 135, 136 



Oil engine, 300, 306 



Oil well, 124 



Olympic games, 265 



Opaque, 103 



Optic nerve, 113 



Optical instruments, 112 



Orbit, defined, 179; earth's, 191 



Oregon Trail, 293 



Organ, relation of to tissues, 230 



Organic foods, 77 



Osmosis, 76 



Ounce, 126 



Ovary, 231 



Overshot wheel, 166 



Oxidation, 21, 119 



Oxide, 21 ; a product of burning, 24 



Oxygen, 23, 24, 59, 78 



Ozone, 59 



Pancreatic juice, 93 



Parallels of latitude, 192 



Paramecium, 229 



Paris green in mosquito control, 224 



Partial eclipse, 190 



Pascal, Blaise, 5 



Pasteur, Louis, 220 



Pasteurization of milk, 85 



Pelton type water wheel, 166 



Penstock, 167 



Pepsin, 92 



Permanent hardness, 58 



Perpetual motion, 148 



Petals, 230 



Petroleum, 123, 124 



Phases of the moon, 186, 189 



Pheidippides, 265 



Phoenicians, 265 



Phonograph, 20 



Photoelectric cell, 287 



Photographic camera, 114 



Photosynthesis, 76. 78 



Physical change, 23 



Piccard, Auguste, 4 



Pictures by wire, 287 



Pinhole camera, 103 



Pistil, 231 



Piston, defined, 7, 12; of pump, 9 



Pitch, 16, 18 



Planetesimal hypothesis, 197 



Planetoid, 179 



Planets differentiated from fixed stars, 

 179; sizes of, 180; orbits of, 181 



Plants, breathing of, 24; parts of used for 

 food, 78; effect of on earth's surface, 

 203 ; insect pests of, 225 ; improvement 

 of by man, 237 



Plas'ma, 95 



Plate of vacuum tube, 283 



Plug fuses, 253 



Plumbing in the home, 73 



Pluto, as a planet, 183 



Pneumonia, 218 



Polaris, 174 



Pole, magnetic, 246 



Pollen, 231 



Pollination, 231 



Pollution of water supply, 63, 69 



Porta's engine, 164 



Potassium, importance of to plants, 213 



Potato, 83 



Potential energy, 162 



Power plant of automobile, 294 



Power stroke, 295 



Precipitate, 62 



Precipitation, 29, 33 



Pressure, of water, 72; of air, 9 



Prevailing westerlies, 40 



Priestley, Joseph, 1 



Primary, winding of transformer, 252; cir- 

 cuit, 277 



Prime meridian, 192 



Printing, development of, 265 



Prism, effect of on li.eht, 106 



Projector, motion picture, 116 



Protein, 80, 81 



Proton, 240, 241 



Protoplasm, 229, 230 



Psychrometer, 31 



Ptolemy, 170 



Pulley, experiment, 156 ; as a lever, 159 



Pumps, 8, 9 



Pupa of house fly, 223 ; of mosquito, 223 



Pupil of eye, 113 



Pure Food and Drug Act, 90, 91 



Putnam, Amelia Earhart, 291 



Quadruplex telegraphy, 270 

 Quality, defined, 16 ; in music, 18 



Buarantine, 226, 227 

 uartzite, 199 

 Queen Mary, 304 



Radiation, 129, 131 

 Radiators, 131, 133 

 Radio, tuning of, 283 ; similarity of to 



wireless, 283 ; recent advances in, 286 ; 



short wave, 286 

 Radio frequency, 282 

 Radio receiving set, 285 

 Radio sending station, 284 

 Radio waves, 107 



