THE FRESH- WATER LOCHS OF SCOTLAND. 105 



Temperature Observations. Temperature observations taken at 

 6.30 p.m. in the deepest part of the loch gave the following results : 



This series shows a range of temperature from surface to bottom 

 amounting to 15'l, the greatest fall being one of 7 0- 8 between 5 and 10 

 feet, there being a further fall of 3-4 between 15 and 25 feet. 



Loch of Drumellie (see Plate XXX.). The Loch of Drumellie (or 

 Marlee Loch) lies about a mile to the east of the Loch of Clunie, and is 

 surrounded by cultivated ground, the fields sloping gently up on all 

 sides. Its shores are stony or weedy, and the narrow portion leading 

 to the outflow is quite choked up with weeds, except for an artificial 

 channel about 4 feet deep leading to the landing-stage, where the burn 

 flows out over a weir. Large yellow masses of decaying vegetable matter 

 were floating everywhere. The loch is about seven-eighths of a mile in 

 length, with a maximum breadth of nearly half a mile, the mean breadth 

 being nearly one-third of a mile, or 37 per cent, of the length. Its waters 

 cover an area of about 175 acres, or over a quarter of a square mile, and 

 it drains directly an area of over 6^ square miles, but since it receives 

 the outflow from the Loch of Clunie and from Rae Loch, its total 

 drainage area is about 23 J square miles an area 86 times greater than 

 the area of the loch. Over 70 soundings were taken, the maximum depth 

 observed being 58 feet. The volume of water contained in the loch is 

 estimated at 221,902,000 cubic feet, and the mean depth at 29 feet, or 

 50 per cent, of the maximum depth. The length of the loch is 78 times 

 the maximum depth and 156 times the mean depth. The Loch of 

 Drumellie forms a flat-bottomed basin, the bottom sinking in two 

 places below the 50-feet line, with shallower water between. The 

 south-eastern 50-feet basin is based upon two soundings of 51 feet, 

 while in the north-western one the maximum depth of 58 feet was 

 observed, situated less than a quarter of a mile from the west end 

 of the loch. The average slope of the bottom is gentle, the steepest 

 slope observed being about midway along the southern shore, where 

 a sounding of 20 feet was taken about 100 feet from the shore, giving 

 a slope of 1 in 5. The area of the lake-floor covered by less than 

 25 feet of water is about 72 acres, or 41 per cent, of the total area of 

 the loch; that covered by water between 25 and 50 feet in depth is 

 about 83 acres, or 47 per cent. ; and that covered by more than 50 feet 

 of water is about 20 acres, or 12 per cent, of the entire area of the loch. 



