INDEX. 



587 



of hydrogen in, 40 nitrogen in, 

 40 oxygen in, 40 ; ash constituents 

 of, 53-55; carbon fixed by, 37, 38; 

 food, absorption of, by, 55; phos- 

 phoric acid in, 204 ; potash in, 216 ; 

 proximate composition of, 36; re- 

 lation of ammonia to, 48-50 ; source 

 of hydrogen in, 40 nitrogen in, 

 40-52 oxygen in, 39, 40. 



Plant-food, absorption of, 490; amount 

 of soluble, in soil, 100 ; early theories 

 on source of, 4; retained by soil, 

 57. 



Plant-roots, grow downwards, 84; 

 nitrification promoted by, 181; 

 openness required by, 83; room 

 required by, 85; soil in relation 

 to, 84. 



Pliny, on lime as a manure, 449 ; on 

 salt as a manure, 465. 



Pockets a source of phosphoric acid, 

 202. 



Poisons, effect of, on nitrifying organ- 

 isms, 176. 



Polstorff on ash constituents of plants, 

 53. 



Polyhallite, potash in, 220, 420. 



Porphyry, in guano, 303 ; phosphoric 

 acidX 202, 211. 



Potash, 212-220, 418-423; in ash of 

 plants, 54 ; in barilla, 420 ; chloride 

 of, 218 ; condition of, in soil, 216 ; 

 in cows' excrements, 280 ; in drain- 

 age-waters, 217 ; in farmyard man- 

 ure, 260 ; in felspars, 220 ; in fleece, 

 217 ; fixed by soils, 58 ; importance 

 of, in soil, 88; in kelp, 420; less 

 important than phosphoric acid, 

 212 ; manures, 218, 418-423 ; muri- 

 ate of, 218, 421 ; necessary for nitri- 

 fication, 171 ; necessary for plant- 

 growth, 55; occurrence of, 213; in 

 ocean, 213; in oxen excrements, 

 280; in pig excrements, 280; in 

 plants, 216 ; position of, in agricul- 

 ture, 212-220; relative manurial 

 value of, 556; Scottish soils sup- 

 plied with, 419 ; in sheep excre- 

 ments, 280; soda replaces, 466; 

 sources of loss of, 217 ; in Stassfurt 

 salts, 214 ; statement of, in analyses 

 of manures, 542 ; in sugar-beet ref- 

 use, 219 ; sulphate of, 218, 421 ; in 

 wood-ashes, 218, 220, 419. 



Potash manures, 218, 418-423 ; appli- 

 cation of, 422, 480 rate of, 423; 

 barilla , as, 420; crops suited for, 

 423 ; relative importance of, 418 ; 

 soils suited for, 423; sources of, 

 419 ; Stassfurt salts as, 420 ; wood- 

 ashes a source of, 419. 



Potassium phosphate in concretionary 

 nodules, 328. 



Potassium sulphate, in Chincha guano, 

 305 ; in concretionary nodules, 328. 



Potatoes, effect of farmyard manure 

 on, 520 ; fertilising ingredients re- 

 moved from soil by, 485; grown 

 with covered manure, 289 ; High- 

 land Society's experiments on, 518 ; 

 manurial constituents in, 282 ; man- 

 uring of, 517-522 in Jersey, 529 

 influences composition of, 521 ; po- 

 tash removed in, 217 ; Rothamsted 

 experiments on, 519, 571. 



Precipitated ammonium phosphate in 

 concretionary nodules, 328. 



Precipitated phosphate, 330, 387. 



Precipitation, treatment of sewage by, 

 436. 



Priestley, discovery of evolution of 

 oxygen by plants, 11 ; on nitrogen 

 in plants, 40. 



Prussiate of potash, manufacture of, 

 353. 



Pugh on sources of plant-nitrogen, 

 42. 



Punta de Lobos guano, 302 ; nitrogen 

 in, 303 ; phosphoric acid in, 303. 



Punta de Patillos, guano deposits at, 

 327. 



Pyroxene, potash in, 220. 



Quartz, evaporation of water from, 



99. 

 Queensland, meat-meal guano from, 



324. 

 Quercitan, experiments of, with 



roses, 8. 



Rape -cake, capable of nitrification, 

 182 ; manurial constituents in, 282. 



Rape-seeds, imports of, 153. 



Raza Island guano, 328 ; phosphoric 

 acid, 330. 



Rectified guano, 311. 



Relative trade values of phosphoric 

 acid, 400. 



