306 PARKS AND PLEASURE-GROUNDS. 



dimensions, as it is technically called. Any one who 

 studies the interesting indications of "position, 1 ' ap- 

 pended by Dr. Lindley.to each of his natural orders, 

 will readily perceive the difficulties which exist in this 

 quarter. Some have thought that a perfect coordina- 

 tion of affinities can be made only on space of three 

 dimensions, as, for example, in the manner the stars 

 are distributed in the firmament. "We can not pursue 

 this subject, which would lead us into the most pro- 

 found depths of the science of botany ; and indeed 

 we need not enter into it, as in the actual formation of 

 an arboretum we are compelled to work on surfaces. 

 Let it be remembered then, that both on account of the 

 fragmentary nature of the materials employed, and 

 their numerous and intertwining relations, as well as 

 the superficial form of the space operated on, the ar- 

 rangement can only be an approximation when con- 

 sidered as a whole. 



Sect. I. — Scientific Treatment of the Arboretum. 



In this section it is proposed to give a sketch of the 

 Natural System of botany as it may be embodied in 

 a living collection of hardy trees and shrubs. This, 

 we are aware, may appear something different from, 

 and discordant with, the other subjects treated in this 

 volume ; nevertheless, on mature consideration, we 

 feel constrained either to present it to our readers as 

 absolutely necessary to render the remainder of our 

 remarks intelligible, or to omit the interesting subject 

 of the arboretum altogether. We might as well dis- 

 cuss the topography of a country without a map, as 



