THE AMMONIA OF THE SOIL. 241 



in fertile soils substances which combiue chemically Avith 

 ammonia. 



Tliat the soil does contain a certain quantity of ammo- 

 nia adhering to the sjuiface of its particles, or, more prob- 

 ably, dissolved in the hygroscopic water, is demonstrated 

 by the experiments of Doussingault and Lewy just alluded 

 to, in all of which ammonia was detected in the air in- 

 cluded in the cavities of the soih In case ammonia Avere 

 physically condensed or absorbed, a portion of it would 

 be carried off in a current of air in the conditions of 

 Boussingault and Lewy's experiments, — nay, all of it 

 would be removed by such treatment sufficiently prolonged. 



Brustlein (Boussingault's Agronomie^ et ■., 1, p. 152) 

 records that 100 parts of moist eartli i:)laced ia a vessel of 

 about 2.]- quarts capacity containing 0.9 parts of (free) 

 ammonia, absorbed during 3 hours a little more than 0.4 

 parts of the latter. In another trial 100 parts of the same 

 earth dried, placed under the same circumstances, absorb- 

 ed 0.28 parts of ammonia and 2.6 parts of water. 



Brustlein found th:it soil placed in a confined atmos- 

 phere containing very limited quantities of ammonia can- 

 not condense the latter completely. In an experiment 

 similar to those jvist described, 100 parts of earth (tena- 

 cious calcareous clay) and 0.019 parts of ammonia were 

 left together 5 days. At the conclusion of this period 

 O.OIG parts of the latter had been taken up by the earth. 

 Tiie remainder was found to be dissolved in the Avater 

 that had evaporated from the soil, and that formed a dew 

 on the interior of the glass vessel 



Brustlein proved fui-ther that while air may be almost 

 entirely deprived of its ammonia by traversing a long 

 column of soil, so the soil that has absorbed ammonia, 

 readily gives up a large sliare of it to a stream of pure air. 

 He caused air, charged with ammonia gas by being made 

 to bubble through water of ammonia, to traverse a tube 1 

 ft. long tilled with small fragments of moist soil. The 

 11 



