664 



Index 



nickel, 29 



nicotine, 345, 383-384, 436, 633 



nimbus clouds, 128, 129, 633, (128) 



nitrates, 307, 355, 443-444, 633 



nitric acid, 356-357 



nitrogen, 27, 29, 30, 34, 36, 355, 633 



and plants, 27, 36, 499 



cycle, 536-537 



in air, 27, 29, 31, 34-35, 36, 301, 

 443 



in soil, 29, 301, 443, 529 



preparation of, 27-28 (28) 



properties of, 27-28, 29, 36 



uses of, 29, 36, 232, 573 

 nitrogen-fixing bacteria, 36, 301, 



443.444, 529, 633, (494) 

 nitrogenous foods, 355 

 nitrogenous wastes, 417 

 Nobel prize winners, 570, 571, 572, 



573, 574 



nodules, 444, (444) 

 non-beneficial plants, 532-533 

 North Star, 162-163, 198 

 nose, 342, 346, 471 

 nosebleed, 483 

 nucleus, 633, (313, 319, 321) 



of atom, 208 



of cell, 313-314, 319, 321, 491-492, 

 (314) 



of sun, 151 

 nutrients, 306, 307, 355-358, 364, 



417, 510, 552, 633 

 nutriment, 373, 452, 633 

 nutrition, 328, 527, 633 



observation, 9 

 ocean, 



currents, 120 



routes, 276 

 Oersted, 215, 560 

 ohms, 211, 212, 633 

 oil, 82, 84, 89, 91, 92, 93, 97, 251, 

 259, 273, 355-358, 633 



burners, 594-595, 596, 633, (594) 



engine, 276 



wells, 92, 93, (92) 

 oil-producing plants, 532 

 Old Ironsides, 271, (271) 



one-celled animals, 319-327, 345, 

 392-393, 413, 453, 454, (313, 319, 

 321, 323) 



opaque, 181, 233, 634 

 opium, 383, 385, 634 

 optic nerve, 188, 634, (188) 

 orbit, 634 



of earth, 150, 151-152 

 of moon, 152-153 

 ores, 297, 634, (297) 

 organic matter, 12, 19, 20, 290, 298, 



301, 634 



organism, 312-313, 634 

 organs, 312-313, 324-325, 330, 339- 

 343, 392, 398-404, 418-420, 423, 

 425-426, 431-434, 491, 634 

 Orion, 164 



ornamental plants, 532 

 oscillations, 234, 634 

 osmosis, 398, 404, 420, 425-426, 634, 



(495) 



in plants, 494-496 



Outdoor Observations, 11, 21, 33, 44, 

 66, 78, 100, 117, 130, 147, 167, 

 179, 194, 202, 214, 227, 239, 254, 

 269, 289, 309, 318, 327, 338, 353, 

 368, 429, 438, 450, 464, 477, 486, 

 503, 513, 526, 534, 545, 554, 

 610 



overshot wheel, 72-73, 634, (72) 

 ovule, 505, 634 

 oxidation, 24, 83, 87, 634 



in living things, 320, 339-340, 355, 



425, 435, 493-494 



results of, 26-27, 83, 85, 192, 301, 

 339, 361 

 (see oxygen) 



oxy-acetylene welding, 25, (25) 

 oxygen, 30, 35, 90, 355, 358, 396, 



416, 508, 535-536, 634 

 chemical action of, 24 

 in air, 23, 27, 29, 31, 34-35, 36, 37, 



301, (35) 

 in burning, 24, 27, 83, 84, 85, 339, 



595 

 in respiration, 35, 320, 322, 339- 



343, 346, 422, 493 

 in water, 23, 24, 26, 29, 30, 31, 



45, 46, 191, 358 

 preparation of, 23-24, (24) 

 properties of, 23-24, 29, 35 

 uses of, 29, 35 



