444 



INDEX 



Noise, 214 



North Star, 8 

 Nucleus, 316 

 Nutrition, 379 



Opaque bodies, 221 

 Organs, 317, 352 

 Orion, 10 



Osmosis, 50, 322, 354 

 Oxidation, 83, 247 

 Oxides, 83, 247, 272 . 

 Oxygen, 81, 247, 272, 321 



Parallels, 20 



Paramecium, 352 



Parasites, 331, 342 



Pascal's law, 112 



Pasteur, Louis, 409 



Patent medicines, 397 



Peach leaf curl, 348 



Peat, 259 



Penumbra, 222 



Perseus, 10 



Petroleum, 263 



Phagocytes, 410 



Pharynx, 89 



Photographic plate, 223, 229, 254, 276 



Photometer, 224 



Physical changes, 95, 246, 247 



Pitch, 215 



Planetary winds, 164 



Planetoids, 2, 5 



Planets, 1, 2 



Plants, 316 



reproduction in, 319 



distribution, 332 



food plants, 339, 387 



textile plants, 340 



diseases of, 342 

 Pleura, 88 

 Pneumonia, 425 

 Poisons, 368-369 

 Poles, 93, 186, 208 

 Pole Star, 9 

 Pollen, 318 

 Pollination, 319 

 Potash, 270, 274, 294 

 Potassium hydroxide, 274 

 Potato scab, 345 

 Potential energy, 41 

 Power, 44, 65 



of water, 66 



of wind, 68 



electric, 209 



Precipitation, 173, 178 

 Preservation, of forests, 337 



of foods, 381 

 Preservatives, 415 

 Pressure, 74, 154 



in liquids, 110 



transmission of, 112 

 Prevailing westerlies, 164 

 Priestley, Joseph, 81 

 Prime meridian, 20 

 Prism, 231 

 Properties, 28 



general, 28 



special, 29 

 Protein, 87, 388 

 Protoplasm, 315-316, 351 

 Protozoa, 408 

 Ptomaines, 413 

 Pulley, 54, 58 

 Pumps, 77-78 

 Pupil, 230 



Quarantine, 431 



Radiation, 145 



Rain, 178 



Rainfall, 178, 299 



Rain gauge, 180 



Rainbow, 232 



Reflected light, 224 



Refraction of light, 226, 231 



Reproduction in plants, 318, 319 



Reptiles, 360 



Resistance, 40, 41 



Respiration, 84, 88 



Retina, 230 



Revolution, 23 



Rivers, 300, 306 



Rocks, 281, 283 



relation to soils, 287 

 Rcemer, 220 

 Roots, 317, 321, 340 

 Rotation, 18 

 Rust, iron, 83 



wheat, 342 



Salt, 254 



as preservative, 384 

 Salts, 272, 275 

 Sanitation, 406 

 San Jose scale, 365 

 Saprophytes, 331 

 Sapwood, 324 

 Satellites, 2, 3 

 Saturation, 102, 173 



