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the carbonate of lime-rocks upon which it falls, and transport the dis- . 

 solved material to, and diffuse it through the soil. 



Prof. Emmons, in his Agricultural Report of the State of New York, 

 says, "Few subjects have enlisted the attention of agriculturists so 

 much as the use and effect of lime in and upon soils. The facts very 

 generally go to prove its great value ; its action, however, has not been 

 so generally understood, * * * * Analysis proves the 

 constant presence of lime in vegetables. There is no doubt but that it 

 should be present in all soils, to supply the wants of vegetation. But its 

 use and functions do not terminate in supplying a material for nutriment: 

 there are certain reactions [decomposition and composition] of lime upon 

 other elements in the soil, which equal in utility the one just referred to. 

 This reaction is upon the silicates of Potash [potash in combination 

 with silex] and other alkalies."* Lime, when in contact with the abovo 

 substances in the soil, has a tendency to decompose them, and set at lib- 

 erty the silica and render it soluble. A mechanical effect attends this 

 chemical action in the soil. It is made lighter, and the whole mass is 

 more porous and friable. Lime is thought by some to favor the decom- 

 position of organic matters in the soil, and thus furnish the materials, of 

 which they are composed, to growing plants in greater abundance than 

 would have been done without the presence of lime. Of the compounds of 

 lime, such as sulphates, phosphates, &c., we shall speak in another place. 

 It will be seen, then, that the offices of lime, as an ingredient of a pro- 

 ductive soil are, first, to supply an element necessary to plants ; secondly, 

 to liberate the alkalies in combination with silica; thirdly, to jender the 

 freed silica soluble that it may be capable of being used in plants; 

 fourthly, to give porosity to argillaceous or clayey soils;f and fifthly, to 

 assist in the decomposition of vegetable and animal matters in he soil. 



Magnesia. — The office of Magnesia, as an element of soils, seems not 

 to be well understood by agriculturists. From the small amount usually 

 found in productive soils, it certainly cannot very effectually act, as lime 

 does, in the same combinations, as a loosener of the soil ; but as it is 

 always found in plants, and since they will not flourish without it, it is 

 necessarily inferred that it is an indispensable ingredient in a good soil. 

 Its general form, in the composition of plants, is in combination with phos- 



* Potash, soda and ammonia are called alkalies ; lime and magnesia, alkaline earths^, 

 i Emmons. 



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