476 BOTANICAL TOUR IN THE 
The sun, after setting, is several degrees nearer the horizon in 
Scotland, than in the south of England. The sun’s dip under the 
horizon is as much less in the Scottish capital, as the latitude of 
London is less than that of the former; or, in other terms, the 
difference of latitude will be the difference of the sun’s horizontal 
depression in the two places respectively. But there is another 
minor cause of the excess of the twilight in Scotland above that — 
of London, viz. the greater purity of the atmosphere. The 
causes of greater atmospheric purity are not so simple as the 
above-stated cause of long twilight; but the facts are well 
known. 
The road lies along the left bank of the eastern branch of the 
Teith, by the little hamlet of Kilmahog, where the celebrated 
Pass of Leny commences. This Pass is formed by a spur of Ben | 
Ledi on the west, and a similar spur of Benvoirlich on the east. 
The river rather rushes than runs through this defile. It forms 
a series of rapids, or a succession of abrupt falls, for the space of 
about a mile: where it issues from the lake it is as placid as the 
Loch itself. The- road is a good one, as all the Highland roads 
are, thanks to General Wade, who made these good roads, or in- 
structed the Highlanders in the art of road-making, an art im 
which they have ever since excelled. After emerging from the 
Pass, the lake, or at least the larger half of it, displays its loveli- 
ness to the traveller, who here has a grand view of the lofty Ben 
Ledi, from its base, washed by the lake, to its summit. On 
this side the elevation is abrupt and steep, and it is along this, the 
eastern side, that the road is made. The lake is bounded on the 
east by the long grassy slopes of the chain of Benvoirlich. Trees 
are rather scanty, especially on the Ben Ledi side of the Loch ; 
but notwithstanding the somewhat bare aspect of the Loch, the 
scenery here is very admirable. It combines many of the ele- 
ments of beauty and some of sublimity. The mighty mass of 
the chain of mountains on the west, and the extensive views on 
the east, partake of the latter character—the sublime; while the 
beautiful is well supported by the placidity of the unruffled sur- 
face of the fine lake reflecting the beams of the morning sun, by 
the quiet pastoral beauty of the Benvoirlich side, by the cottages 
and small farms, few and far between, and by the hanging woods 
that frmge the mountains at the upper end of the view. These, 
combined into one whole, formed a prospect not readily effaced 
