PREFACE. 



As the rapid sale of the previous editions of 

 this work affords the surest proof that it has 

 met the wants of those for whose use it was 

 designed, it may be asked why I have now 

 made so many alterations and additions. My 

 answer is, that I have done so in order that 

 my book may keep pace with the improving 

 spirit of the times. For this reason, I have 

 rewritten the chapter on manures, and made 

 various other alterations to meet the present 

 views of scientific men as regards chemistry 

 when applied to horticulture. It is true that, 

 in most cases, the results are the same as prac- 

 tice has long dictated ; but it is pleasant to 

 find theory and practice agree, which was not 

 always the case formerly. In fact, the most 

 interesting feature in the new doctrines is, that 

 they explain scientifically why practices suc- 

 ceed, which formerly appeared quite at variance 

 with theory. 



The other alterations are of minor import- 

 ance, but they are numerous ; and, in fact, 

 every page has been carefully read over, and 

 improved to the utmost of my power. 



J. W. LOUDON. 



Bayswatee, Jan. 20, 1851. 



