Objects to be Accomplished by Plowing. ' 139 



liow much is there which is in such Vi physical and chemical con- 

 dition as to be available by the rootlets of the growing plant. 



As the success of the practical farmer depends almost entirely 

 upon a knowledge of these principles, it will be necessary to give 

 a brief explanation of them, especially as it is necessary to com- 

 prehend them, if we nre to attain to clear understanding of the 

 theory of the plow. 



Mr. Way filled several glass vases, furnished with stop-cocks 

 at the bottom, with dry soils of various kinds; he then poured 

 into each of them the drainage water from a barn j^ard loaded 

 with stercoraceous and saline matters which, after it had filtered 

 through the soils, was drawn off through the stop-cock. That 

 which had passed through the stiffest clay came off limpid and 

 apparently pure, the taste being almost like that of rain water; 

 that which passed through a very sandy soil was but slightly 

 changed in taste or appearance. The power of a soil to absorb 

 the manurial matters seemed to depend upon the relative amount 

 of aluminous matter contained in it, those having the greatest 

 abundance absorbing most, those having the greatest amount of 

 sand having the least. It was, however, established beyond a 

 doubt that all soils had a peculiar power of absorbing manurial 

 matters, which could not bo separated by the action of water or 

 by any other way than by the absorbent action of the rootlets of 

 a growing plant. 



Dr. Vcelcker has followed up these investigations with great 

 assiduity and success. He saturated various kinds of soils with 

 a solution of caustic ammonia, containino- 23.24 o-rains of ammonia 

 to the imperial gallon, and ascertained the amount of ammonia 

 that was absorbed by each kind of soil. He thus found that 3,000 

 grains of a calcereous clay absorbed 2,758 grains of ammonia 

 from 14,000 grains of the solution. From the same quantity a 

 fertile loamy soil abstracted 2,604 grains; 3,000 grains of a stiff 

 clay soil absorbed 2,262 grains of ammonia; 3,000 grains of a 

 sterile sandy soil retained 3,228 grains of the solution; 3,000 

 grains of the soil of a rich pasture took up 1,728 grains of 

 ammonia. 



He next agitated these soils, which had been saturated with 

 ammonia water of the above mentioned strength, with a solution 

 of ammonia, which was twice as strong as the preceding, and 

 found that they now, curiously enough, absorbed very nearly 



