2 INTEODUOTION. 



ceptible of being divided, are held together by no 

 bond of union, and that there is no explanation of 

 their connexion with general principles, by which 

 alone the soundness of this or that rule of practice 

 may be tested ; the reader is therefore usually oblig- 

 ed to take the excellence of one mode of cultivation 

 and the badness of another, upon the good faith of 

 gardening authors, without being put into poesession 

 of any laws by which they may be judged of before- 

 hand. Horticulture is by these means rendered a 

 very complicated subject, so that none but practised 

 gardeners can hope to pursue it successfully ; and, 

 like aU empirical things, it is degraded into a code of 

 peremptory precepts. 



3. It will nevertheless be found, if the subject is 

 carefully investigated, that in reality the explanations 

 of horticultural operations are simple, and free from 

 obscurity ; provided they are not encumbered with 

 speculations, which, however interesting they may 

 be in theory, are only perplexing in practice, in the 

 present state of knowledge. When, for example, 

 chemical Uluetrations, unless of the simplest kind, 

 or minute anatomical questions, or references to the 

 agency of the electrical fluid, are discussed, the sub- 

 ject becomes embarrassed with considerations which 

 are too refined for the apprehension of the majority 

 of readers of gardening works, and which have little 

 obvious application to practical purposes. Instead, 

 therefore, of introducing points of obscure or doubt- 

 ful application, or such as are not absolutely requi- 

 site for the explanation of phenomena, all which ne- 

 cessarily tend to complicate the theory of horticul- 



