MA.NTJRES. 



in all soils ; but, in its pure state, is not capable of 

 being dissolved, and therefore cannot be used by 

 plants. The alkalies (as has been stated) have the 

 power of combining with it, making compounds, which 

 are called silicates. These are readily dissolved by 

 water, and are available in vegetable growth. Xow, 

 if a soil is deficient in these soluble silicates, it is well 

 known that grain, etc., grown on it, not being able 

 to obtain the material which gives them strength, 

 will fall down or lodge; but, if such measures 

 be taken as will render the sand soluble, the other 

 conditions of fertility being present, the straw will be 

 strong and healthy. Alkalies used for this purpose, 

 come under the head of those manures which de- 

 velop the natural resources of the soil. 



Again, much of the mineral matter in the soil is 

 combined within particles, and is therefore out of the 

 reach of roots. Lime, among other things, has the 

 effect of causing these particles to crumble and ex- 

 pose their constituents to the demand of roots. There- 

 fore, lime has for one of its offices the development 

 of the fertilizing ingredients of the soil. 



3d. Those manures which improve the mechanical 

 condition of the soil. 



The alkalies, in combining with sand, commence 

 their action on the surfaces of the particles, and 

 roughen them rust them, as it were. This roughen- 

 ing of particles of some soils prevents them from 

 moving among each other as easily as they do when 

 they are smooth, and thus keeps the ground from being 

 compacted by heavy rains, as it is liable to be in its 



