THE FRESH-WATER LOCHS OF SCOTLAND. 
67 
half being comparatively shallow, while the deeper water occurs in the 
eastern half, the maximum depth having been found about one-eighth of 
a mile from the eastern end. The 10-feet basin approaches quite close to 
the eastern shore, and is about one-third of a mile in length, enclosing 
the 20-feet basin, which is about one-fifth of a mile in length. About 
61 per cent, of the lake-floor is covered by less than 10 feet of water, 
while about 12 per cent, is covered by over 20 feet of water. No 
bench-marks were found near the loch, but a little distance up the river 
which feeds it there is a spot-level of 1134 feet. There was little 
evidence of much rise and fall in the level of the water, the range 
possibly not exceeding 2 feet. The temperature of the surface water 
varied from 47°-4 to 50°'5, a range of 3°T, the higher readings being 
taken in shallow water near shore. Headings at 10 feet and at 20 
feet near the centre of the loch gave 48° in each case, the surface 
temperature at the same 'time being 47°‘6. 
Less than a mile to the east of Lochan Srbn Smeur is Lochan Loin 
nan Donnlaich (or Lochan Loin nan Dubhach, or Loch-an-Londonich), 
said to contain large trout. When visited, many rocks and boulders 
were observed showing above the water, and grass filled the bay at 
the outlet. 
Loch Eigheach (see Plate XVIII.). — Loch Eigheach (or Eaigh), 
about 3 miles from where the river Gaur passes its waters into Loch 
Rannoch, is an expansion, or rather three expansions, of the river 
Gaur, the two western expansions lying on a higher level than the 
eastern one, and hence strong currents run in an easterly direction. 
In high floods the whole area is practically submerged. A large part of 
the loch is covered by reeds, and the bottom is very weedy. The entire 
loch is nearly nine-tenths of a mile in length, with a maximum breadth 
of less than a quarter of a mile, the mean breadth being one-tenth of a 
mile. Its waters cover an area of about 591 acres, or less than one-tenth 
of a square mile, and it drains directly an area of nearly 14 square 
miles, but since it receives the outflow from Lochan Srbn Smeur and 
from Lochs Laidon and Ba, &c., its total drainage area is nearly 631 
square miles, or 705 times the area of the loch. The loch was surveyed 
on April 21, 1902, about 80 soundings being recorded, the maximum 
depth observed being 28 feet. The surface of the eastern expansion 
was found by levelling to be 818‘2 feet above sea-level, and the water 
apparently rises about 3| feet above its level on the date surveyed. The 
volume of water contained in the loch is estimated at 15,794,000 cubic 
feet, and the mean depth at 6 feet, or 22 per cent, of the maximum 
depth. The eastern expansion is the deepest, the maximum depth of 
28 feet having been found to the west of the island near the east end 
of this expansion ; the north-western expansion has a maximum depth 
of 7 feet observed not far from the outlet, but the majority of the 
