84 
BATHYMETRICAL SURVEY OF 
in length, from north to south, and also in maximum breadth from east 
to west, the mean breadth being over a quarter of a mile, or 45 per cent, 
of the length. Its waters cover an area of over 100 acres, or about 
one-sixth of a square mile, and it drains an area ten times greater — 
over square miles. About 60 soundings were taken, the maximum 
depth observed being 70 feet. The volume of water is estimated at 
108,333,000 cubic feet, and the mean depth at nearly 25 feet, or 35 per 
cent, of the maximum depth. The length of the loch is 44 times the 
maximum depth and 126 times the mean depth. A ridge crosses the 
loch at the narrowest part near the middle, the greatest depth on which 
is 34 feet. On both sides of this ridge the water deepens, the maximum 
depth in the southern basin being 45 feet, while the main deep basin 
lies to the north of the ridge, the maximum depth of the loch (70 feet) 
having been found less than a quarter of a mile from the north-eastern 
angle of the loch, where there is a small 50-feet basin about one-tenth of 
a mile in length ; a short distance to the north-east is an isolated 
sounding of 50 feet, comparatively close to the north-east shore, 
separated from the 50-feet basin by a sounding of 38 feet. The 25-feet 
basin is a continuous area half a mile in length and over a quarter of a 
mile in breadth. The area of the lake-floor covered by less than 25 feet 
of water is about 53| acres ; that covered,^ by water between 25 and 50 
feet in depth is about 44 J acres ; while that covered- by more than 50 
feet of water is about 2J acres. Loch Derculich was surveyed on May 
2.7, 1903; the elevation above the sea could not be determined. 
Temperature Observations . — A series of temperatures was taken 
in the deepest part of the loch at 8 p.m. 
following results : — 
on May 27, 1903, ^ 
Surface ... 
55°-0Fahr. 
10 feet ... 
51°-0 ,, 
15 „ 
49° -0 ,, 
■25 „ { 
47° -7 ,, 
50 „ 
47°T ,, 
65 , , 
47° 0 ,, 
70 „ 
47° '0 ,, 
The range of temperature from surface to bottom was 8°-0, there being 
a fall of 4°‘0 between the surface and a depth of 10 feet, and a further 
fall of 3°’3 between 10 and 25 feet. A comparison of these temperatures 
with* those taken in Lochs Daimh and Giorra on the previous day shows 
that the water in Loch Derculich was much warmer from surface to 
bottom than in the two lochs referred to : at the surface the temperature 
was about 5°, and at 10 feet 3° to 4° higher; at the bottom it was 4° 
higher than at the bottom of Loch Daimh, and 1° higher than at the 
bottom of Loch Giorra at a much less depth. 
Loch Scoly (see Plate XXVI.). — Loch Scoly, a small hill loch in 
