158 
BATHYMETRICAL SURVEY OF 
the River Spey, and immediately to the south of Loch an Eilein, into 
which it drains. Irregular in outline, the loch trends in a south-west and 
north-east direction, and is less than half a mile in length by one-fifth of a 
mile in maximum breadth, covering an area of about 25 acres. The 
maximum depth of 41 feet was recorded in a small basin at the south-west 
end of the loch ; there is a second deep basin, having a maximum depth of 
29 feet, lying in the wide part of the loch towards the north-east end, 
these two basins being separated by a shoaling covered by only 4 feet of 
water, where the outline of the loch is constricted. The volume is 
estimated at 10 million cubic feet, and the mean depth at 91^ feet, nearly 
three quarters of the lake-floor being covered by less than 10 feet of water. 
The loch was surveyed on October 14, 1903, when the elevation was found 
to be 889*3 feet above the sea, or 6 feet lower than that determined by 
the Ordnance Survey officers in September, 1868, viz. 895*2 feet. This 
lowering is due to the banks of the stream giving way, and consequent 
outflow into Loch an Eilein. The surface temperature was 46°*1 Fahr. 
Loch an Eilein (see Plate LX.) lies about 3 miles south of Aviemore, 
amid picturesque surroundings. At the time of the survey, a couple of 
ospreys were nesting in the ruins of the castle on the island (see Fig. 34). 
Somewhat crescentic in outline, the loch exceeds a mile in length, along 
the axis of maximum depth from south-west to north-east, the maximum 
breadth being nearly half a mile. The superficial area is about 130 acres, 
and the drainage area, including Loch Gamhna, is about 2| square miles. 
The maximum depth of 66 feet was recorded towards the south-west end, 
and deep water occurs also near the north-east shore, where soundings in 
51 and 47 feet were taken, the water shoaling in the central part of the 
loch to a depth of 20 feet. The volume of water is estimated at 144 million 
cubic feet, and the mean depth at 25J feet, 54 per cent, of the lake-floor 
being covered by less than 25 feet of water. 
The loch was surveyed on October 14, 1903, when the elevation was 
found to be 839*6 feet above the sea, or nearly a foot lower than that 
observed by the Ordnance Survey officers on September 21, 1868, viz. 
840*4 feet above sea-level. Temperatures taken in the deepest part of 
the loch showed a range from surface to bottom of only Fahr. : — 
Surface ... 
49°-2 Fahr. 
10 feet . . . 
49°-0 ,, 
20 „ ... 
48°*8 „ 
30 „ ... 
48°.8 „ 
40 „ ... 
48°*8 „ 
50 „ ... 
48°*7 „ 
60 „ ... 
48°*6 „ 
Loch MorlicJi (see Plate LXI.), the largest of the Spey lochs in super- 
ficial area, lies in Glen More, surrounded by woods, about 4 miles east 
of Aviemore. The loch is sub-rectangular in outline, the length from 
