383 
Nitrogen, loss from soils, 141, 142. Percolation, 109. 
nitrifying bacteria, 148, 149. Periodic variation of climate, 297. 
plant nutrition, 133, 141, 364. Periodical phenomena, 232. 
sugar beets, 262. Perret, water and plant nutrition, 114. 
Nobbe, germination, 44. Petermann, fixation of nitrogen, 161. 
Nordlinger, variations of temperature in forests, 7. | Pfeffer, asparagin, 49. 
Normandy, thermal constants, 175, 176. thermal constants, 241. 
North Cape, Norway, germination, 39. Phantupimeter, 96, 273. 
gluten in wheat, 41. Phenological observations, 290-294. 
Norway, acclimatization, 220. Phenology, 167-294. 
rye, 41. climatic tables, 272-277. 
Notation, phenological, 291, 293. epochs of, 167,181. 
Nutrition, réle of water, 114. Linsser’s law, 214, 215. 
of plants, 22, 140. lists of plants, 172, 191, 226, 242, 243. 
temperature, 172, 211. 
Oak, phenology, 281-290. thermal constants, 336. 
water consumption, 113. suntmation of temperature, 279-290. 
Oats, cellulose, 18. Philadelphia, Pa., bacteriological examination of 
drought, 337, 338. air, 180. 
environment, 314. Photantupimeter, 96, 2738. 
fertilizers, 162. Photochemistry of sunshine, 92. 
light, 39. Photographic measurement of sunshine, 95, 
nitrogen, 136. Physiological constant, 224-230. 
phenological constant, 177. Physiological method, 6. 
thermal constants, 320. Piche evaporimeter, 106, 246, 273. 
Turkish, 217. Pieper, germination, 44. 
water consumption, 113, 123. Pine, water consumption, 113. 
Observations, phenological, 290-294. chlorophy] and light, 38. 
Ohio, oats in, 338. Pinus. See Pine. 
Optimum temperature, 36. Plant growth, 15, 244, 245. 
Orange, France, thermal constant of wheat, 39. respiration, 18. 
Oregon, soil temperatures, 62. Plants, acclimatization, 215. 
Orel, Russia, plant development, 231. and air, 18. 
Orenburg, Russia, acclimatization, 231. climate, 22. 
season of vegetation, 221. fixation of nitrogen, 136-161. 
Orkneys, plant development, 39. phenological lists, 172, 191, 226, 239, 240. 
Orleansville, Algeria, thermal constants, 176. soil moisture, 114. 
Orotava, Teneriffe, acclimatization garden, 221. sunshine, 168. 
Oxygen, absorption by plants, 18, 47-52. temperature, 53, 235, 236. 
absorption by seeds, 46, 50. water drainage, 115. 
in asparagin, 49. water supply, 116-127. 
Ozone and thunderstorms, 341. Plat experiments, 352-355. 
Plumb, maize, 332-3338. 
Pagnoul, assimilation, 78, 79.. plat experiments, 353. 
fixation of nitrogen, 150, 161. Poa pratensis, 299, 307. 
sugar beets, 259-263. Poggioli, light and vegetation, 26. 
Papilionacez, fixation of nitrogen, 157. Polar region, vegetation, 39. 
Para, Brazil, insolation, 82. Pollen, dissemination, 129, 291. 
photochemical researches, 93, 94. Polperro, England, epoch of awakening, 184, 185. 
Paris, France, germination of wheat, 39. Postelberg, Austria, rainfall and harvest, 111. 
insolation, 82. Potato, cellulose, 18. 
See, also, Montsouris. date of planting, 309, 310. 
Parma, Italy, phenology, 185. dryness and sunlight, 80. 
plant development, 231. harvest and water supply, 127. 
Pasteur, light and vegetation, 37. water consumption, 113-119. 
modification of bacteria, 157. Potsdam, Germany, atmospheric electricity, 131. 
Pauchon, light and germination, 37, 42-52. Pouillet, actinometer, 82. 
northern vegetation, 40. Poulkova, Russia, phenology, 213-215. 
Peas, albuminoids, 18. Prazmoftski, fixation of nitrogen,‘151-155. 
fixation of nitrogen, 136, 153, 155, 160. Prediction of crop, 247-251, 363. 
thermal constant, 335-337. tables for, 272-277. 
time of flowering, 242. time of harvest, 175, 189. 
water consumption, 113, 124. Prillieux, nitrifying bacteria, 152. 
Penhallow, soil temperatures, 53, 63. Prize crops, 164. 
Pendleton, Oreg., soil temperatures, 62, 63. Progress of vegetation, 183, 185. 
Pennsylvania, maize experiments, 333-334. Protection from frost, 340. 
Pentads, in phenology, 273-274. Protein, 17. 
Pepper, acclimatization, 307, Protoplasm, 16. 
