454 Action of the Atmoapliere upon newly -deepened Soil. 



degree, the power of removing from solution in water certain 

 animal and vegetable substances, but still more the alkaline 

 bases ammonia and potash, and the earths magnesia and lime, 

 The.se bases the soils were capable of separating from their salts, 

 and retaining more or less, in spite of tlie action of water." And 

 experimenting upon silicates artificially prepared, the same 

 chemist found that ammonia could be removed by soils from 

 solution in water in virtue of their containing either the double 

 lime or the double soda silicate — the two double silicates sup- 

 posed to be most usually present — whereas it was found that the 

 lime salt alone was capable of removing ammonia from its at- 

 mospheric solvent. Professor Way, therefore, concluded that to 

 these double silicates this power of absorbing and combining 

 with substances from solution is probably due. 



I may here insert the following short table, extracted from 

 some of Way's experiments, and which should have come in at 

 a previous page. It shows the amount of ammonia absorbed by 

 1000 grains of different kinds of soils, exposed on a sheet of 

 paper to a moist atmosphere charged with carbonate of am- 

 monia : — 



It will be observed in the three last columns that in the case 

 of the London clay the under soil absorbed more ammonia than 

 the surface — a result apparently adverse to the opinion which I 

 expressed, that the surface-soil would be a better absorber than 

 the subsoil ; but in this case the result is evidently owing to the 

 much less amount of sand found below, and probably has nothing 

 to do with the amount of humus or organic matter ; sand being, 

 as has been abundantly shown, a very bad absorber. 



Action of Organic Acids. — The effect of these upon the soil 

 in hastening the decomposition and dissolution of the mineral 

 matter is probably sometimes considerable ; they may be con- 

 sidered as originating from the influence of the oxygen of- the 

 air upon the carbonaceous matters of the soil, and therefore any 

 effects produced by them may be viewed as indirectly proceeding 



