THE FRESH- WATER LOCHS OF SCOTLAND. 411 



Dun na Seilcheig. and Rutkven, and draining into the latter. Low 

 but craggy hills border the loch on the west and north, the crags of 

 Creag Dearg facing the west end. The loch is of somewhat oblong 

 form, with the long diameter east and west. The length is nearly 

 two-thirds of a mile, the greatest breadth one-third of a mile, the mean 

 breadth one-fifth of a mile. The superficial area is about 86 acres, and 

 the volume of water 103 millions of cubic feet. The drainage area 

 is nearly one square mile. Only one stream, the Allt Bhreac, flows 

 in on the north, and at the east end the burn flows out towards Loch 

 Ruthven. 



Loch a' Choire is 865 feet above the sea. The bottom forms a simple 

 basin, with the deeper water towards the east end. The 25-feet contour 

 follows the shore-line, except at one point on the north, where a sounding 

 of 18 feet lies far out. The 50-feet area, one-sixth of a mile in length, 

 lies all to the east of the centre of the loch. The maximum depth is 60 

 feet, and the mean depth 27 J feet. The temperature at the surface on 

 April 28, 1903, was 43-5 Fahr. ; at 25 feet, 42-5 ; and at 50 feet, 42'5. 



Loch Ruthven (see Plate CV.). A loch of fair size, some 2J miles 

 east of Loch Ness, opposite Urquhart bay, and half a mile south of 

 Loch Dun na Seilcheig. It is a narrow loch, with its central line 

 much curved, but having its general direction east to west. Precipitous 

 wooded hills, the Torr M6r and the Torr Beag, rise abruptly from the 

 north shore. On the south the crags of Stac Gorm and Craig Ruthven 

 border the eastern part of the loch, while towards the west the ground 

 is lower and more open. 



Loch Ruthven is very narrow in the middle, slightly expanded at the 

 east, and much expanded at the west end. The length is 2J miles, the 

 maximum breadth, close to the lower end, fully half a mile, and the 

 mean breadth a quarter of a mile. It has a superficial area of about 

 368 acres, or over half a square mile, and a volume of 180 millions of 

 cubic feet. The drainage area is 4 square miles. The burn from Loch 

 a' Choire comes in near the upper end of the loch, and there are no 

 other burns of any size. The outflowing stream is the river Farigaig, 

 which falls into Loch Ness at Inverfarigaig. 



When surveyed on April 27 and 28, 1903, the loch was 2 feet below 

 a bench-mark, 703' 1 on the south shore at the upper end, and would 

 therefore be 701*1 feet above the sea. This figure is at variance with 

 two spot-levels on the north shore, where 687 and 688 feet are marked 

 near the west end, and there is no dam to account for so much difference. 

 The Ordnance Survey, on May 8, 1871, made the level 7004 feet, only 

 a few inches lower than our measurement. Loch Ruthven is on the 

 whole very shallow, having a mean depth of only 11 feet. The small 

 eastern expansion has a flattish sandy bottom, with a greatest depth 

 of 8 feet. 



