54 THE PLANTS OF THE GRAMPIANS. 
same latitude or elevation. In looking at those lists, a 
stranger to the botany of the mountains would see Lonicera 
Periclymenum and Azalea procumbens both included in the 
list of species growing between 1000 and 2000 feet, but he 
could not learn from such tables that the Lonicera always 
ceases several hundred feet in absolute elevation before the 
Azalea appears. In afterwards publishing similar lists of 
plants seen upon the hills of Cumberland, I adopted narrower 
stages, of 500 feet each, and included only the plants ob- 
served within a morning walk of Keswick. The ascertained 
range of each species was thus shown with greater precision, 
but of course the lists were still liable to the incongruous 
assemblages above stated, though to a less extent. In this 
present paper, I propose to attempt a nearer approach to 
exactness; first, by limiting attention to a portion only of 
the Highlands; and secondly, by specifying the range of 
height for each species singly, with as much precision asl 
have been able so ascertain its range. When writing the 
lists in the Edinburgh New Philesophical Journal, I had not 
sufficient data for the object here proposed ; and though the 
lists in question can now be much improved upon, in 
respect of precision, I do not pretend, as yet, to give more 
than approximations to truth. In all observations of this 
nature there is a double chance of inexactness ; since it is not 
to be expected that a botanist will always see the highest 
or lowest specimen of any species when ascending and 
descending a mountain ; nor can he be expected always f? 
avoid the many sources of error in calculating the heights of 
the stations where they have been seen. 
But before introducing the lists of altitudes, it may be a 
well to give some explanation respecting the process by which 
they have been ascertained. Such an explanation will indi- 
cate the degree of reliance to be placed on observations of 
this kind; and it will, at the same time, supply some hints 
and instructions for any other botanical observer, who may be 
inclined to pursue similar investigations. 
The instrument used is Adie's Sympiesometer, in its im- 
BEE AE E 
