THE PLANTS OF THE GRAMPIANS. 59 
ably extended to all the estimates which involve it. Thus, 
the estimates of height about Clova, Braemar, and adjacent 
hills, rest on the accuracy of calling Braemar Castle 1070 
feet above the sea, which is the height calculated by Dr. 
Skene, from barometrical observations. 
Nor can it be necessary to tell botanists, that the highest 
and lowest stations in which I have chanced to see any plant, 
during brief occasional visits to the mountain tracts, are not 
likely to be the very highest and very lowest, at which those 
plants really grow; more especially so, because I have rather 
sought to be within the true limits, in stating the altitudes, 
that in case of any inaccuracy in calculation, &c., the figures 
might be on the right side. Other observers may, therefore, 
expect to find some of the plants in higher stations than 
I have here assigned for them; but they will be much less 
likely to find that I state the upper limits too high, or the 
lower limits too low. 
A reflecting botanist will see that other objects can be com- 
bined with these excursions for ascertaining the altitudinal 
limits of plants. For instance, the temperature of the air 
being taken at each resting place, a tolerable knowledge of 
the summer climate of the mountains, in its relation to al- 
titude, may be thus gained incidentally. The detached ther- 
mometer is also at hand to try the temperature of springs and 
lakes ; and the knowledge so acquired, will throw light upon 
the changes of vegetation at different altitudes. The condi- 
tion of the plants in respect to size and habit, of progress 
towards maturity, and many other matters of interest to the 
student of nature, will also pass under his notice, upon 
Which it is needless here to enlarge. 
The botanist whose leading object is such as here ex- 
plained, must unfortunately forego the greatest gratifications 
of the collector. I have found botanists slow in under- 
Standing why a measurer must be an unsuitable companion 
to the collectors of specimens; but a few words will now 
make this evident. To preserve the integrity of his sym- 
P'ésometer and thermometers, he must avoid rocky precipices 
E 
