22 On the Chemical Properties of Soils. 



Experiment 7. 



The solution left in the bottle from Experiment No. 4 was 

 drawn off as thoroughly as possible ; 7000 grains of solution 

 No. 3, containing *176 grains of ammonia in 1000 of liquid, 

 were then added, and after repeated shakings the whole was 

 left to settle for four days. 



Ammonia. 

 Grains. 



Before contact with soil 1000 grains of the mixed solutions! -^_ 

 contained / 



After contact with soil 1000 grains of the solution contained '096 



051 



Therefore '051 grains of ammonia were removed from every 

 1000 grains of liquid, or '480 grains from the whole solution, 

 and retained by 1750 grains of soil, which had already taken up 

 *175 grains of ammonia from the weaker solution. 



Ammonia. 

 Grains. 



1000 grains of soil thus absorbed from the weakest solution '100 

 From the stronger solution "274 



374 



Or in both experiments '374 grains were removed and retained 

 by 1000 grains of soil. 



Thus in all cases much more ammonia was removed from 

 the stronger solutions than from the weaker, and was retained by 

 the soil in addition to the quantity previously absorbed from the 

 weaker solution. Thus the total amount of ammonia absorbed 

 by 1000 grains of soil was in 



Ammonia. 

 Grains. 



Experiment No. 5 1-687 



No. 6 -737 



No. 7 -374 



It will be observed that in Experiment No. 1, 1000 grains of 

 soil removed 1'32 grains of ammonia from the strongest solution. 

 The same solution, taken in the same quantity as in Experiment 

 No. 1, and left in contact with soil which had already absorbed 

 64 grains of ammonia, removed an additional quantity of 1'047 

 grains, or altogether 1*687 grains. 



It thus appears not only that the strength of the solution 

 influences the amount of ammonia which can be retained by the 

 soil, but likewise that the quantity of liquid which is passed 

 through a soil will affect the proportion which a soil is capable 

 of abstracting from a given solution. 



From a large quantity of an ammoniacal liquid it appears to 



