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 42'7 Fahr. 



10 feet 42-5 



50 42'l 



100 42-l 



150 4l-9 



200 41-7 



300 41-7 



350 ,, 41-6 



400 4l-5 



4-_V, 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 Ibs. 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 6J 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 



