88 
BATHYMETRICAL SURVEY OF 
The range in the temperature of the water from surface to bottom was 
thus the fall of temperature between the surface and a depth of 
5 feet amounting to 5°’7, that between 5 and 10 feet amounting to 2°-7, 
and that between 10 and 25 feet to 2°*3. A comparison of these 
temperatures with those taken in Loch Derculich two days previously 
shows that the temperature of the whole body of water in Loch Kennard 
was lower than that in Loch Derculich (except at the surface — which 
may be due to the fact that the observations in Loch Kennard were 
made in the early afternoon, while those in Loch Derculich were taken 
in the late evening). 
Loch Skiach (see Plate XXVI.). — Loch Skiach, situated in Strath- 
tay, containing large trout as well as pike, flows into Little Loch Skiach 
(which was not sounded) by a short burn with a slight fall, and thence 
by the Pitleoch burn into the Ballinloan burn shortly before it joins 
the river Bran. It is surrounded by low, rounded, heather-clad hills 
with scattered boulders, and the shores are of clean shingle with 
boulders. It is very irregular in outline, the longer axis being nearly 
north and south, and the bottom is also irregular. It is over three- 
quarters of a mile in length, and nearly half a mile in maximum 
breadth, the mean breadth being nearly one-fifth of a mile, or 25 per 
cent, of the length. Its waters cover an area of about 98 acres, or 
over one-seventh of a square mile, and it drains an area six times 
greater — an area of nearly one square mile. Eighty-five soundings were 
taken in Loch Skiach, the maximum depth observed being 55 feet. 
The volume of water is estimated at 77,185,000 cubic feet, and the mean 
depth at 18 feet, or 33 per cent, of the maximum depth. The length of 
the loch is 75 times the maximum depth, and 228 times the mean depth. 
Near the middle a ridge crosses the loch from south-east to north-west, 
on which the depth is less than 20 feet; this ridge separates the two 
deep basins, of which the southerly one is the deeper, the maximum 
depth of 55 feet having been recorded about a quarter of a mile from 
the southern end of the loch, while the greatest depth recorded in the 
northern basin was 45 feet in two places. The two 25-feet basins are 
each under a quarter of a mile in length. Near the middle of the loch 
the slope of the bottom is very steep in places — for instance, a sounding 
of 33 feet was taken off the eastern shore at a distance of about 100 feet, 
giving a slope of 1 in 3, and a sounding of 26 feet about the same 
distance off the western shore gives a slope of 1 in 3*8. The area of the 
lake-floor covered by less than 25 feet of water is about 77 acres, or 79 
per cent, of the total area of the loch; that covered by water between 
25 and 50 feet in depth is about 20 acres, or 20 per cent. ; while that 
covered by more than 50 feet of water is only about IJ acres, or 1 per 
cent. Loch Skiach was surveyed on June 12, 1903, and the level of the 
surface of the water was determined by levelling from bench-mark as 
being 1385-7 feet above the sea. 
