X PREFACE. 



understand those really simple general principles, founded 

 upon the very nature of things, upon which all his under- 

 takings are based. Among the simplest operations, it is 

 one thing to prune a tree properly, so as to keep it in 

 a healthy and productive state, with just the proper 

 proportion of fruit and leaf-buds ; and quite another to cut 

 away a certain bulk of wood annually, merely because 

 pruning is generally thought a beneficial practice. Similar 

 comparisons might be drawn from many familiar cases 

 between the injurious results of empirical practice, as 

 contrasted with those which follow the application of correct 

 principles, and some knowledge of vegetable physiology. 



The notes appended to this edition are rendered necessary 

 in some cases, by the difference between the climate of 

 England and of this country; or they relate to different 

 applications of principles : it is hoped that they will in some 

 degree increase the value of the work to the American 

 reader. a. j. d. 



Newbwrgh, on the Hudson, March, 1852. 



A few notes signed 6. were contributed to the first American 

 edition by Professor Gray. 



