Absorb and retain Ammonia. 245 



erately stiff soil, would no doubt be far better. Mr. Way's 

 experiments prove that the soil has a power of absorbing pot- 

 ash, soda, magnesia, and phosphoric acid, as well as ammo- 

 nia ; and if we add to these one more substance, namely, 

 lime, we have most of the chief elements of manure. 



As we said a fortnight since, when adverting to these 

 very curious and important experiments, the subject is not 

 yet half investigated, and there appears to be many chemical 

 points not satisfactorily explained ; some of these, as we then 

 suggested, probably depend on mechanical rather than on 

 chemical causes. Pure white clay, which had been boiled 

 for two hours in strong muriatic acid, and which therefore 

 evidently did not contain any free carbonate of lime, was 

 nevertheless found to decompose a solution of muriate of 

 ammonia which was filtered through it ; a portion of the 

 ammonia was absorbed, while the acid passed through in 

 combination with lime ; though, as may be supposed, far less 

 ammonia was absorbed than when a clay containing free 

 carbonate of lime was used as the filter. From this result 

 we learn that such clay, which always contains a small 

 quantity of lime, though it does not give up that lime to the 

 action of a strong chemical solvent (such as boiling muriatic 

 acid,) nevertheless does part with it readily under the influ- 

 ence of the much weaker solvent powers of a solution of 

 muriate of ammonia. Another, and an equally surprising 

 result, was obtained on endeavoring to ascertain whether a 

 given soil would absorb the same relative proportion of 

 ammonia from solutions containing diff'erent salts of that 

 substance. An equal weight of soil was employed in each 

 case, and it was found that when a weak solution of pure 

 caustic ammonia was used, and there was therefore no chem- 

 ical affinity to be neutralized or overcome, every thousand 

 grains of the soil took up about a grain and a half of ammo- 

 nia ; on the other hand, when a solution of muriate of am- 

 monia was used, in which case the salts had to be decom- 

 posed by lime under the influence of the soil, then nearly 

 one-third more, or two grains of ammonia, was absorbed by 

 every thousand grains of the soil. 



