88 BATHYMETRICAL SURVEY OF 



The range in the temperature of the water from surface to bottom was 

 thus ll-4, 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 0> 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 1J acres, or 1 pel- 

 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. 



