MANURES. 153 



ANIMAL, VEGETABLE, MINERAL, AND MIXED 

 MANURES. 



285. It has been common to speak of manures as 

 animal^ vegetable^ and mineral. A few, as hair, horns, 

 hoofs, leather clippings, sweepings from the woollen 

 factory, &c., are almost wholly of animal origin. 

 Others, as decayed straw, vegetable mould from the 

 woods, peat, swamp muck, &c., are almost wholly of 

 vegetable origin. And others still, as plaster, ashes, 

 common salt, saltpetre, lime, soda, &c., are purely of 

 mineral origin ; while a few, including barn-yard ma- 

 nures, are of a mixed character, partaking of an ani- 

 mal, vegetable, and mineral origin. 



MANURES, STIMULANTS, AND AMENDERS. 



286. Substances used to benefit soils and crops, 

 have also been distinguished into manures^ stimulants^ 

 and amenders. Those of which the principal object is 

 to furnish food for plants, have been called manures ; 

 those whose main object is to bring into action other 

 substances already in the soil, have been called stimu- 

 lants ; and those designed chiefly to change the physi- 

 cal condition of the soil, as when clay is put upon 

 sand, or sand upon clay, or peat upon either, have 

 been denominated amenders^ their office being not so 

 much to afford nutriment to plants, nor to stimulate 

 the soil, as to better its physical state. 



287. Unfortunately for the latter distinction, the 

 object of an application is seldom confined to one of 



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