ARTIFICIAL MANURES. 355 



are so abundant and so universally distributed that they do 

 not demand much attention ; but some others, on the other 

 hand, have been distributed by nature with so sparing a 

 hand, that our constant care should be given to keeping our 

 supply of them undiminished. They exist only in the soil ; 

 the winds cannot waft them to us, nor do they come, as am- 

 monia does, in every summer shower. They are the hard 

 currency of our banking system, and our business will always 

 be limited by the amount we have in our vaults, and by the 

 promptness with which we make good their loss when we 

 have put them in circulation. 



This fact has created a demand for artificial manures* 

 the theory of whose production is, that the phosphate of lime 

 which has found its way into the bones of animals, and ha& 

 thus become, for the moment, unavailable to the farmer, 

 shall be returned by some process which shall convert refuse 

 bones into manure, or that it shall be replaced from some 

 other source, as from the phosphatic guanos from which 

 superphosphate of lime is largely made; and that potash, 

 lime, &c., shall be collected, in the form of ashes," <fec., <fec., 

 and returned to the soil. 



If all the artificial manures that have been put into the 

 market had been honestly made, the demand for them would 

 have been much greater even than it now is. 



But the fact that their composition can be ascertained 

 only by careful chemical analysis, which farmers are incom- 

 petent to make, has led to no end of fraud, and one never 



