THE FRESH- WATER LOCHS OF SCOTLAND. 
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which is, according to the Ordnance Survey maps, 270 feet above sea- 
level, has a total length of about 4 miles, with a maximum width of less 
than three-quarters of a mile. The mean breadth is about two-fifths 
of a mile, or 704 yards, being 10 per cent, of the length. Its waters 
cover an area of about 1030 acres (or over 1 J square miles), and it drains 
an area nearly eighteen times greater, or about 18,300 acres (28 J square 
miles). The total number of soundings taken in Loch Vennachar was 
423, an average of 263 per square mile, the average depth of these being 
41 feet, and the greatest depth observed being 111 feet (18 J fathoms), 
so that it may be regarded as a relatively shallow loch. The bulk of 
water contained in the loch is estimated at 1,903,000,000 cubic feet, 
and the mean depth at 42| feet (7 fathoms), being 38 per cent, of the 
maximum depth. The length of the loch is 190 times the maximum 
depth, and 498 times the mean depth. 
FIG. 6. — LOCH VENNACHAR, LOOKING SOUTH-WEST. 
( Photo gra.'pli hi/ G. W. Wilson.) 
It will be observed from an examination of the map that the loch is 
deeper in the eastern than in the western portion, the western end being 
shallow and covered with weeds, so that one must proceed nearly a mile 
from the west end of the loch before encountering depths of 50 feet, 
and this is merely a small patch separated from the principal 50-feet 
depression by a distance of nearly two-thirds of a mile. In August the 
water in the loch is at its lowest, and the weeds at the west end most 
abundant. The principal 50-feet depression is about 2 miles in length, 
with a mean breadth of about one-third of a mile and a maximum 
breadth of nearly half a mile. It includes two 100 -feet depressions : the 
first one is very irregular in shape, situated approximately in the centre 
of the loch, and contains the greatest observed length (111 feet), which 
lies towards the northern shore; the second one occupies the central 
portion of the large 50-feet depression, the greatest depth observed 
