THE FRESH-WATER LOCHS OF SCOTLAND. 
341 
10 and 20 feet, which is nearly equal to a fall in temperature of one 
degree per foot of depth. Reference has elsewhere been made to the 
large range and rapid fall of temperature observed in Lochs Monzie- 
vaird, Achilty, and Dubh,* and the temperatures here given from 
Loch na Beinne Baine afford another instance for comparison. 
Loch Lungard (see Plate LXXXII.). — Loch Lungard (or Longart, 
or Glasletter) lies at the head of Glen Cannich, about 5 miles to the 
north of Loch Affric. It trends east and west, and is IJ miles in length, 
with a maximum breadth towards the west end of one-third of a mile, 
whence the loch narrows gradually towards the east. The superficial 
area is about 216 acres, or one-third of a square mile, and the area 
draining into it is nearly 23 square miles. The maximum depth of 
129 feet was observed in a central position, but towards the east end. 
The volume of water is estimated at 599 million cubic feet, and the 
mean depth at nearly 64 feet. The loch was surveyed on October 7, 
1903, when the elevation of the lake-surface above the sea was found, 
by levelling from bench-mark, to be 761 *3 feet, which is nearly identical 
with the level observed by the Ordnance Survey officers on October 14, 
1867, viz. 761-2 feet. When surveyed the water was about its normal 
level, and in floods might rise about 3 feet. 
Loch Lungard is extremely simple in conformation, the bottom 
sloping down on all sides towards the deepest part, not the slightest 
irregularity being indicated by the soundings, while the contour-lines 
coincide approximately with the outline of the loch. This is shown in 
both the longitudinal section A-B and the cross-section C-D on the 
map. The 50-feet basin is IJ miles, and the 100-feet basin rather under 
a mile, in length, and they are comparatively wide, so that the loch is 
of a ffat-bottomed character, as is shown by the following table, giving 
the areas and percentages between the contour-lines ; — 
0 to 
50 feet 
87 acres 
40 per cent. 
50 ,, 
100 „ 
81 „ 
88 „ 
Over 
100 „ 
48 „ 
22 „ 
216 „ 
100 
Temperature Observations . — The following series of temperatures, 
taken at 2 p.m. on the date of the survey in the deepest part of the 
loch, indicates a range of only l°-2 Fahr. throughout the body of 
water : — 
Surface 
25 feet 
50 „ 
125 ,, 
49° *2 Fahr. 
49° -0 „ 
48° '8 ,, 
48°-0 „ 
See p. 276. 
