INTRODUCTION. 7 



it concerns every one, and every one ought to 

 study its principles. To every branch of the 

 manufactures of this country, this knowledge 

 has been of the most essential importance : 

 overcoming difficulties hitherto deemed insur- 

 mountable; opening new sources of employ- 

 ment, where none had previously existed; im- 

 proving others to such an extent, that the 

 different productions would scarcely be recog- 

 nised as belonging to the same class, and 

 lastly, doing all these things so much better 

 and so much cheaper than by the old processes, 

 that the national wealth has thereby been im- 

 mensely increased, and comforts and even luxu- 

 ries have been brought within the means of 

 all classes. 



It can hardly be necessary to cite examples 

 in which chemistry has produced these results. 

 We have only to look at the various manufac- 

 tures of iron, glass, porcelain, the powers of 

 steam, and galvanism — destined to surpass 

 steam in its effects, the discovery of the Davy 

 lamp, &iG. to be convinced of the benefits che-. 

 mistry has conferred on mankind, and of its 

 importance as a general study. 



And if this knowledge is beneficial to the 

 generality of persons, of what paramount im- 

 portance must it be to the agriculturist, whose 

 every act entails a chemical operation, and 

 who, unless he is enabled in some measure 

 to understand the cause and effect of these 

 changes, will be pursuing his avocation almost 

 by chance, or at least without the means of 

 availing himself of many advantages that may 



