THE FKESH-WATER LOCHS OF SCOTLAND. Ill 



are rocky. The length, in a straight line joining the ends, is 1 J miles, the 

 maximum breadth, near the upper end, a quarter of a mile. The eastern 

 basin is largest and deepest, with stoep sides and nearly flat centre, and 

 the maximum depth of 55 feet. The middle basin is similar, but smaller, 

 and has a depth of 48 feet. Between these basins the depth is only 22 

 feet. The western basin is separated from the middle basin by a strait, in 

 which the depth is only 12 feet the slope is less steep, and the maximum 

 depth is 36 feet. Another constriction, with a depth of 10 feet, separates 

 a small expansion at the west end of the loch, with a depth of 23 feet. 

 The area of the loch is about 144 acres, or nearly a quarter of a square 

 mile, the mean depth is over 18 feet, and the volume of water 116 millions 

 of cubic feet. The drainage area is extensive, measuring 14f square miles, 

 and comprises the whole southern slope of the Merrick, the northern slope 

 of the Lamachan, and a number of lochs to the north-east, which were not 

 surveyed. 



The principal streams feeding the loch are the Pulnabrick and Puchan 

 burns on the north, and the Gairland and Glenhead burns, which unite 

 and enter the head of the loch. The Water of Trool flows out to the 

 south-west, and joins the Minnoch about 2 miles distant. There is a 

 sluice at the outflow. The surface on August 14, 1903, was 246'35 

 feet above sea-level, or rather higher than the elevation determined by 

 the Ordnance Survey on June 26, 1894, viz. 245'9 feet. The temperature 

 varied over 2 from surface to bottom, thus : 



Surface 58 C> 3 Fahr. 



10 feet 58-2 



20 57-0 



30 56-8 



40 56-5 



50 56-0 



From the following table it will be seen that in the fifteen lochs under 

 consideration 594 soundings were taken, and that the aggregate area of 

 the water surface is over 2 square miles, so that the average number 

 of soundings per square mile of surface is 280. The aggregate volume of 

 water contained in the lochs is estimated at 527 millions of cubic feet. 

 The area drained by these lochs is nearly 35J square miles, or 16J 

 times the area of the lochs. 



