MANURES. 121 



of water. But an equal effect may be obtained, at a 

 less cost, by decomposing ground bones with green 

 manure or swamp-muck. 



6. WOOD ASHES, leached and unleached. The 

 former, though less valuable, still retain most of the 

 constituents of the unleached, having lost only a por- 

 tion of their soda and potash. In either form, ashes 

 are a most useful fertilizer, and adapted to nearly 

 every description of soil. 



7. PLASTER, or sulphate of lime. Plaster is the 

 name given to ground gypsum. It is generally bene- 

 ficial to corn, and sometimes in a remarkable degree ; 

 its effect depending very much on the character of the 

 soil. 



8. LIME, oxide of calcium. That obtained from 

 burnt shells is by many considered superior to any 

 other. The best results from the use of lime are found 

 in soils that abound in vegetable matter. This mate- 

 rial is found to be much better applied in small quan- 

 tities, occasionally repeated, than in large quantities 

 at one time. 



9. SALT, chloride of sodium. There is much dif- 

 ference of opinion in regard to this fertilizer, but 

 there are doubtless soils on which it is useful. It has 

 a tendency to check the growth of weeds, and its 

 effect on grain is to increase the solidity and weight. 



10. LIME AND SALT MIXTURE. This may be pre- 

 pared by adding two parts of lime to one of common 

 salt, or by slacking the lime with a saturated solution 

 of salt. The preparation should be made several 

 months before usin g. 



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