THE FRESH- WATER LOCHS OF SCOTLAND. 359 
the table that the change is very gradual, but quickest in the upper 
50 feet, where half of the total range occurs : — 
Surface 
10 feet 
50 ,, 
100 „ 
150 „ 
200 „ 
300 ,, 
350 ,, 
400 „ 
425 „ 
42° -7 Fahr. 
42°-5 „ 
42°-l „ 
42° -1 „ 
41°-9 „ 
41°-7 „ 
41°-7 „ 
41°-6 „ 
41°-5 „ 
41°-5 ,, 
Loch Arkaig (see Plate LXXXIV.). — Loch Arkaig is a long, narrow, 
curved loch, running nearly due east and west, the lower end about 
1 mile west of Loch Lochy and 10 miles north of Fort William. 
The lower part of the loch is well wooded, picturesque, and romantic, 
with hills to north and south reaching well over 2000 feet in height 
(see Fig. 53). The upper part is barer and grander, the mountains 
exceeding 3000 feet in height. A road runs along the north side of the 
loch, deteriorating towards the west end into a rough track which leads 
to Loch Nevis and Loch Morar. Several wooded islands enhance the 
charm of the scenery, and on one of these is one of the few nesting- 
places of the osprey, still occupied by the birds at the time the survey 
was made. There is very good fishing in Loch Arkaig, and lake trout 
up to 10 lbs. in weight were taken from the loch while the survey was 
going on. 
Loch Arkaig is 12 miles long, of somewhat irregular outline, but 
broadest in the middle parts and tapering towards each end. The 
greatest breadth is- nearly a mile, the mean breadth half a mile. The 
maximum depth is 359 feet, the mean depth 152| feet. The surface has 
an area of square miles, and the loch drains an area of 88 square 
miles. The volume of water is estimated at 26,573 millions of cubic 
feet. 
No large loch drains into Loch Arkaig, but several very small lochs 
do so, the largest being Loch a’ Bhlair, a mile to the north. The chief 
streams enter at the west end, where a short river brings the drainage 
of Glens Pean and Dessary, and on the south side, where the stream 
from Glen Camgharaidh enters near the upper end, and that from Glen 
Mallie near the lower end. Only mountain torrents enter on the north. 
The river Arkaig, a mile long, conveys the overflow of Loch Arkaig 
into Loch Lochy. 
When surveyed, in the middle of June, 1902, the height above sea- 
level was found to be 139-0 feet ; the officers of the Ordnance Survey 
found the elevation to be 139-8 feet above the sea on July 10, 1869. 
The basin of Loch Arkaig is nearly simple, the slight irregularities 
