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mer should also take into consideration their 

 saline components, though these latter have a 

 depreciated worth compared with nitrogen. 

 It is thus that guano and bones, which contain 

 a large quantity of phosphates, should be pre- 

 ferred, their proportions of nitrogen being 

 equal, to other manures the components of 

 which besides nitrogen are inert. 



Those manures which contain but little of 

 mineral matters, as ammoniacal salts, blood, 

 wool, &c., must, previous to their application, 

 be supplied with the elements which are 

 wanting. 



It is very strange that the decisive results, 

 from the use of lime and sulphate of lime in 

 the culture of those plants which absorb a 

 large amount of that earth, Iiave not induced 

 an extension of the experiments to all the 

 salts useful in vegetation. It seems evident, 

 that if its application in excess, upon the sur- 

 face of fields which already contain it, pro- 

 duces good effects in the cultivation of clover, 

 it will be still moreefficacious upon thoselands 

 which have but traces of this salt. 



The best manure therefore is that ivhich 

 will restore to the earth all the sicbstances 

 removed from it by the crops. There is 



