394 
BATHYMETRICAL SURVEY OF 
The series taken in May shows a range of barely 2° from surface to 
bottom, while the series taken in September shows a range of over 6°, a 
fall of 2° having been recorded between 90 and 100 feet. It will be 
observed that the whole body of water was warmer in September than 
it was in the preceding May, the bottom reading in September being 4° 
higher than the surface reading in May, while the difference between 
the two bottom readings is about 6°, and between the two surface 
readings about 10°. 
Loch Uanagan (see Plate XCVIII.). — Loch Uanagan lies a little 
more than a mile to the south of Fort Augustus, on Loch Ness. It is a 
narrow little loch lying parallel to the Caledonian canal, which is one- 
third of a mile to the west, and is separated from Loch Uanagan by the 
Torr a Choiltry, a high ridge with steep sides, densely covered with fir 
trees. This hill rises abruptly from the west side of the loch to a 
height of 384 feet, some 266 feet above the surface of the water. 
Loch Uanagan is half a mile long, and has a maximum breadth of 
one-eighth of a mile. The superficial area is about 25 acres, and the 
volume of water 18 millions of cubic feet. The drainage area is about 
1^ square miles. The only stream of any size flows in at the south end, 
and near the north end a small burn flows out to the east, where a small 
part of the loch has been cut off by the railway, and joins the river 
Tarff half a mile to the north. The height of the loch above sea-level 
on July 2, 1903, was 118-2 feet. 
Loch Uanagan is very shallow, the greater part of it less than 
10 feet deep. Only one-fifth of the area is over 25 feet in depth, the 
25-feet contour enclosing a narrow area one-sixth of a mile long, nearer 
to the east shore, and the maximum depth of 43 feet is near shore, the 
slope here being steep. The steep slope of the hill on the west is not 
continued under water, the loch on that side being shallower. 
Temperature Observations . — The surface temperature on July 2, 
1903, was 63°-0 Fahr., and a serial taken at 2.30 p.m. on September 24, 
1903, gave the following results; — • 
Surface 55° -4 Fahr. 
10 feet 54° -8 „ 
20 ,, 53°-6 „ 
30 „ 53°-6 „ 
40 „ 52°-8 „ 
Loch Beag (by Clunie) (see Plate XCIX.). — A small triangular loch 
about a quarter of a mile west of the upper end of Loch Clunie. It is 
simply an expansion of the river Clunie, and is at the same level as 
Loch Clunie. It is one-third of a mile long by one-fifth of a mile 
broad. The area of the surface is about 26 acres, and the drainage 
area very extensive, viz. 20 square miles. The volume of water is 
