12 



and retain for the subsistence of the plants the amtuouiacal and other 

 salts which form the most valuable constituents of manure, and the 

 highly important investigations of Professors Way* and Voelckert on 

 this subject, have had a most important bearing on practical agricult- 

 ure, especially to the rational treatment and application of farm-yard 

 manure and the economical use of artificial manures. 



The investigations of Professor Way have given a new direction to 

 the chemical study of soils, and the subject has been taken up by Liebig, 

 Knopp, Heuneberg, Stohmau. Brustlein, Peters, Voelcker, Warington, 

 and other chemists. [In the pages of the Journal of the Eoyal Agri- 

 cultural Society of England will be found the reports of many important 

 investigations undertaken in England to which the reader is referred for 

 more detailed information.] 



These several investigations have shown that the property of absorb- 

 ing, retaining, and modifying the composition of manures belongs to 

 every soil in a greater or less degree. 



ABSORPTION OF AMMONIACAL SALTS BY VARIOUS SOILS. 



The ammonia floating in the atmosphere is continually being washed 

 into the soil, carried into it by the rains. The clay, oxide of iron, and 

 the organic matter contained in the soils, perform the important func- 

 tion of absorption. This property of clay may be one of the reasons why 

 clay lauds are more suitable to wheat than are sandy soils. Although 

 clay has this property of retaining more of these absorbed substances 

 than sands or loams, yet it is evident that these latter soils must receive 

 the same amount of fertilizing matter from the rains, only they have 

 less ability for retaining or storing it up.J 



In regard to the absorption of ammonia and its salts by various soils, 

 the- following summary is taken from Dr. Voelcker's paper u Ou the 

 chemical properties of soils :" 



(1) All of the soils experimented upon had the power of absorbing ammonia from 

 its solution in water. 



(2) Ammonia is never completely removed from its solution, however, weak it may 

 be. On passing a solution of ammonia, whether weak or stroug, through any kind 

 of soil, a certain quantity of ammonia invariably passes through. No soil has the 

 power of fixing completely the ammonia with which it is brought in contact. 



(3) The absolute quantity of ammonia which is absorbed by a soil is larger when a 

 stronger solution of ammonia is passed through it, but, relatively weaker solutions 

 are more thoroughly exhausted than stronger ones. 



(4) A soil which has absorbed as much ammonia as it will from a weak solution, 

 takes up a fresh quantity of ammonia when it is brought into contact with a stronger 

 solution. 



(5) In passing solutions of salts of ammonia through soils, the ammonia alone is ab- 



* Journ. Royal Agric. Soc., vol. xi, p. 313. 



t/Jw/., vol. xiv, p. 808. 



tThe Soil of the Farm. 



Journ. Royal Agric. Soc., vol. xxi, p. 123. 



