XIV INTRODUCTION. 



cliemical principles. Hence, a knowledge of this 

 science enables us more readily to understand the 

 processes of the manufacturer, points out the best and 

 most economical mode of effecting his objects, and 

 teachos how that which was before useless and of no 

 value, may be converted into sources of wealth and 

 happiness. 



It is needless to point out examples of th^ influence 

 which the progress of chemistry has had on our 

 manufactures ; for every one of them owes, more or 

 less directly, its present improved condition to the 

 labors of the chemist. Such being the case, it be- 

 comes interesting to inquire, What has chemistry 

 done for agriculture, the most important, because the 

 most necessary, and most extensively practised, of 

 all the arts? It is remarkable that agriculture 

 should have received infinitely less assistance from 

 the labors of chemists, than any other art ; but this 

 ceases to be surprising, when we consider how little 

 attention was paid by the ancient chemists to that 

 subject. — The chemistry of the earthy and metallic 

 substances presented to them easier and more attract- 

 ive objects of inquiry; they were led away by the 

 visionary hope of discovering a mode of making 

 gold ; and they consequently neglected everything, in 

 order to try all sorts of experiments, in the vain idea 



