THE FRESH-WATER LOCHS OF SCOTLAND. 
61 
(2968 feet) rising to the north-west, and Creag a’ Chaoruinu Eagan 
(2260 feet) to the south. On its south side the shore of the loch rises 
steej)ly to the ridge of Creag an Eilein, the highest part of which 
(1137 feet) is about u, quarter of a mile distant. The loch trends north- 
east and south-west, and is 2 miles in length, with a maximum breadth 
of less than half a mile near the north-east end, whence it tapers off 
towards the south-west, the lower end for half a mile being merely a series 
of small expansions of the river Carron. Its w^aters cover an area of about 
283 acres, and it drains directly an area of 31^ square miles, but since it 
receives the overflow from Loch ^gamhain the total drainage area is 39 
square miles. The maximum depth of 179 feet was observed op]30site the 
highest part of Creag an Eilein, less than half a mile from the north-east 
end. The volume of water is estimated at 823 million cubic feet, and the 
mean depth at nearly 67 feet. The loch was surveyed on August 6 and 7, 
1902, when the elevation was found to be 93*1 feet above the sea. 
The main body of the loch is simple in conformation, the contour-lines 
following approximately the shore-line, but there are two 100-feet basins, 
the main basin being over three-quarters of a mile in length, and approach- 
ing very close to the north-east end, soundings in 108 and 111 feet having 
been taken about 120 yards from shore ; the smaller basin is based on a 
single sounding in 105 feet, and is sej>arated from the main basin by a 
slight shoaling, covered by 97 feet of water, north of Eilean Mor. There 
are two small basins over 25 feet in dej^th in the river-expansions at the 
south-western end of the loch, the larger having a maximum depth of 
32 feet, the smaller based on a sounding in 28 feet. 
Temperature Observations . — A series of temperatures taken in the 
deepest part of the loch at 4.30 p.m. on August 7, 1902, gave the following 
results : — 
Surface ... 
54°-5 Fahr. 
25 feet . . . 
54°*5 „ 
50 „ ... 
54O-0 „ 
60 „ ... 
53°-5 ,, 
70 „ ... 
50°-0 „ 
75 „ ... 
49°-3 „ 
100 „ ... 
47°-5 „ 
165 „ ... 
47°*0 „ 
These observations show a range from surface to bottom of 7J°, a fall 
of 3J° being recorded between 60 and 70 feet, while the decrease in 
temperature both above and below the “ sprungschicht ” is gradual. 
From the following table it will be seen that in the twelve lochs under 
consideration nearly 1100 soundings were taken, and that the aggregate 
area of the water surface is nearly 4 square miles, so that the average 
number of soundings per square mile is 281. The aggregate volume of 
water contained in the lochs is estimated at 4921 millions of cubic feet. 
The area drained by these lochs is nearly 98J square miles, or 25 times 
the area of the lochs. 
