The first edition of this book -wtis written in 1853, when 

 the writer was full of the enthusiasm that comes with the 

 first years of study ; when a very elementary knowledge 

 of the subjects of n^hich it treats made the whole plan of 

 vegetation, cultivation, and manuring seem easy and simple. 

 In some instances, rather vague fancies were presented as 

 sound theories; and the perplexing uncertainties which 

 beset the path of the more thorough student were ignored — • 

 because unknown. 



The observation and experience of the intervening years 

 have sadly clouded some of these fancies, and the veil which 

 hangs about the true theories of agriculture has grown 

 harder to penetrate, — the difHculties in the way of precise 

 knowledge have not lessened with closer acquaintance. 



Notwithstanding its faults, the book received a very cor- 

 dial welcome at the hands of the public, — more because 

 such a book was much needed, than because of its real 

 value, and it ought, long ago, to have been rewritten. 



The present edition has been carefully revised, and it is 

 believed that its doctrines are such as the positive teachings 

 ol chemistry, and the more enlightened practice of farming, 

 will justify ; still, it is ofiered with more hesitation than was 



