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 0- 4 to 50'5, a range of 3'l, the higher readings being 

 taken in shallow water near shore. Readings 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 Sron 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 Eiglieach (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 59 J 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 Sron Smeur and 

 from Lochs Laidon and Ba, &c., its total drainage area is nearly 63 J 

 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 J 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 



