418 



Description of a Design for the 



follows. Where there is abundance of room, the groups may 

 all be made circular, and may proceed in one line along the 

 margin of the walk, their circumferences being all at one 

 uniform distance from it, as uijig. 74. ; but where the space is 



74 



limited, the line for the small groups will require occasionally 

 to be made circuitous, and the form of the large groups to 

 be made irregular, or, at all events, of greater length than 

 breadth, for the sake of adjusting the whole collection of 

 plants to the extent of the ground and its outline. Thus, in 

 Jig. 73., something is gained by the circuitous direction of the 

 groups at e, and by making group f of an elongated shape ; 

 for, if group f had been made circular, it would have inter- 

 fered with the continuity of the arboretum. The position of 

 all the groups of herbaceous plants being fixed on, and their 

 boundary lines being cut out with a spade, the dotted lines 

 which bound the arboretum are then to be traced on the 

 ground, according to the rule before mentioned ; and the po- 

 sitions of the trees are to be found by the following rules. 

 Keep within the boundary lines ; let no tree or shrub be 

 nearer another than 5 ft., and let every species be at least 2 ft. 

 in advance of the other ; that is, measuring on the lines a b. 

 The reason for placing one tree, or shrub, somewhat in ad- 

 vance of the other, is, that a guide is thus given to the posi- 

 tion of any species or variety which may come the next [to 

 any other species or variety ; thus, if we have found Carpinus 



28383, we know that the variety 



28383 



will be in advance of 



the species to which it belongs ; whereas, if we did not know 

 this, we might be seeking it either on a line to the right or 



