ADVERTISEMENT AND 

 DEDICATION. 



After the numerous books of late pub- 

 lished on the subject of agriculture, and 

 particularly those of Mr. Kirwan, Sir Hum- 

 phry Davy, Sir John Sinclair, Sir Joseph 

 Bankes, and others, another may appear 

 superfluous ; but all who have read those 

 different authors with attention, must have 

 been convinced that however elaborate their 

 works, there is such a discrepancy in their 

 opinions on some of the most important 

 operations of agriculture, as to justify an 

 attempt to bring them to the test of 

 a just investigation and comparison, by 

 tracing their principles in their progress 

 from cause to effect. I am not a pro- 

 fessor of chemistry, nor an -extensive 

 A 2 



