224 
BATHYMETRICAL SURVEY OF 
of water is estimated at 90 million cubic feet, and the mean depth 
at 18|- feet. The breadth of the loch at the position of the deepest 
sounding is 31 times the depth. The shore development is 2-45, and 
the insulosity nil. 
Loch Coulin is very irregular in outline, and is cut up into three 
basins, the north-western basin having a maximum depth of 32 feet, 
and the central basin a maximum of 22 feet. The main basin is 
confined to the broad south-eastern part of the loch, and the contour- 
lines approach very close to the eastern shore, off which the slope is 
steep. There are two isolated soundings less than 25 feet within this 
area, and deep water is found at the entrance of the river Coulin. 
FIG. 40. LOCH COULIN, LOOKING NORTH. 
(Photograph by Mr. T. N. Johnston, M.B., C.M., F.R.S.E.) 
The area covered by less than 25 feet of water is over 80 acres, or 72 
per cent, of the entire area of the loch. 
Temperature Observations . — A series of temperatures was taken in 
the deep part of the loch at 5 p.m. on July 24, 1902, with the following 
results ; - — 
Surface 
5 feet 
10 „ 
15 „ 
20 „ 
30 ,, 
40 „ 
57° -0 Fahr. 
57°-0 ,, 
57°T „ 
57° -0 „ 
55° -5 ,, 
54° *8 ,, 
53° -0 „ 
