310 ma:<ukes and their application. 



one which has been longest in use, and has been applied most 

 abundantly. I have already referred to it when speaking of 

 exhaustion, and have stated that it promotes the exhaustion of 

 the soil by liberating potash from its compounds in the soil, and 

 otherwise enabling the roots of plants ta find their food more 

 easily. I have said tliat the action of lime in the soil is a very 

 complex one. It affects the soil both physically and chemically, 

 but to enter into detail on this subject would take me far beyond 

 the limits of this paper. I will content myself with mentioning 

 one or two of its functions which are perhaps not so commonly 

 known. 



The effect of lime on the mechanical condition of clay land is 

 very remarkable. It has been shown by Schloesing that lime 

 tends to coagulate clay soil into fine particles, rendering it easily 

 permeable by water. If some clay soil is put in a funnel and 

 water allowed to flow steadily through it, it will drop through 

 bright and clear for some time, but by and by the drops become 

 muddy and continue so until the clay is all washed away or the 

 funnel is choked up with mud which refuses to let the water flow. 

 If while the muddy drops are falling a little lime is sprinkled on 

 the surface of the soil the drops soon begin to fall clear again 

 and continue to do so until the lime is again w^ashed out, when 

 the clay will once more flow aw^ay rendering the water drops 

 muddy. This is a little experiment which any one can try for 

 himself, and it conveys a great amount of information. When 

 rain falls continuously on clay land it soon ceases to be absorbed; 

 if the land is fiat it becomes covered with muddy pools, but if 

 it is steep the water runs down in streams, carrying the finely 

 divided soil along with it. What has occurred here is exactly 

 what occurred in the experiment referred to. The excess of rain 

 has washed away the lime and other salts from the superficial 

 layer of the soil, and its porous granular condition has been 

 changed into a muddy one, and long after the rain has ceased, 

 this muddy condition remains until, by capillary attraction, lime 

 salts come up from below and cause the mud to cohere into fine 

 granular masses, through which water can once more drain away 

 freely. Other salts also possess this character to some extent, 

 but none to so great an extent as lime. 



Lime is a strong base and has a powerful affinity for acids. 

 In the soil are to be found various acids with which it may unite, 

 and notably carbonic acid. Carbonic acid is always being formed 

 during the decay of organic matter, and anything which takes 

 away carbonic acid hastens that decay. Whenever any chemical 

 action is going on, if the products which are being formed are not 

 taken away, the action very soon ceases, but as soon as the 

 products are taken away, the action goes on again. Hence it is 

 that lime, by taking away carbonic acid, hastens the progress of 



