PREFACE. 



The combination of practical skill and experi- 

 ence with scientific investigation and knowledge, 

 the former giving results, the latter affording rea- 

 sons for these results, and sketching the outlines 

 of farther experiments, has always appeared the 

 surest ground of obtaining information of the 

 greatest value on all subjects of natural science. 



A concise and simple explanation of some of the 

 prominent facts and laws of vegetable physiology so 

 that they might become known to, and guide those 

 agriculturists and horticulturists, whose time is too 

 much occupied to permit them to go into the detail 

 of the reasoning involved in the numerous experi- 

 ments scattered through many volumes and pe- 

 riodicals, must be of advantage. 



The valuable experiments of Knight, the works 

 of Lindley, Decandolle, Herbert and others, the 

 Compilations of Loudon, and some of the results 

 of the extraordinary attention paid within the last 



