116 BATHYMETRICAL SURVEY OF 



at other places the shores are less steep, and surrounded by smooth, 

 rounded, heather-covered hills. The water was very dark in colour, 

 and, though there was apparently no great amount of inflow, there was 

 a considerable outflow. Loch Fender is one-third of a mile in length 

 from north-east to south-west, and one-fifth of a mile in maximum 

 breadth, the mean breadth being over one-tenth of a mile, or 32 per 

 cent, of the length. Its waters cover an area of over 22 acres, and it 

 drains an area nine times greater an area of over one-third of a square 

 mile. Nearly 60 soundings were taken, the maximum depth observed 

 being 78 feet. The volume of water contained in the loch is estimated 

 at 30,998,000 cubic feet, and the mean depth at 31| feet, or 41 per 

 cent, of the maximum depth. The length of the loch is 22 times the 

 maximum depth and 55 times the mean depth. Loch Fender forms a 

 simple basin, the bottom sloping down on all sides to the deepest part, 

 which is approximately centrally placed, but nearer the north-east than 

 the south-west end, the maximum depth of 78 feet having been observed 

 about 300 feet from the north-eastern shore. The average slope of the 

 bottom is very steep, especially off the south-eastern shore, where were 

 recorded soundings of 29 feet 20 feet from shore, 26 feet 30 feet from 

 shore, and 17 feet 20 feet from shore, giving gradients of 1 in 0*7 and 

 1 in 1-2. Off the north-western shore the gradient is gentler, and the 

 north-west angle, where the burn flows into the loch, is comparatively 

 shallow and obstructed by weeds. The area of the lake-floor covered 

 by less than 25 feet of water is about 11 acres, or 51 per cent, of the 

 total area of the loch ; that covered by water between 25 and 50 feet in 

 depth is about 5 acres, or 21 per cent. ; and that covered by more than 

 50 feet of water is about 6 acres, or 28 per cent, of the entire area of 

 the loch. Loch Fender was surveyed on June 5, 1903, and, from spot- 

 levels near the loch, it was estimated that the elevation of its surface 

 was approximately 1888 feet above sea-level. 



Temperature Observations. Temperatures taken in the deepest part 

 of the loch at 1 p.m. gave the following results: 



Surface 58-OFahr. 



5 feet 57-8 ,, 



10 52 -0 



15 ,, ... ... 4o-0 ,, 



25 ,, 44-0 f> 



50 43'0 



75 ... 42-4 



This series shows a range of temperature from surface to bottom 

 amounting to 15-6, there being a fall of 12-8 between 5 and 15 feet 

 (i.e. 5-8 between 5 and 10 feet, and 7-0 between 10 and 15 feet). The 

 decrease of temperature in the layer of water between 10 and 15 feet is 

 thus equal to l-4 per foot, whereas the fall is only 1 in the underlying 

 layer between 15 and 25 feet. 



