THE FRESH- WATER LOCHS OF SCOTLAND. 179 



line along the centre line to near both ends. The temperature on June 30, 

 l!">4, had a range of 3 r -2, viz. 



Surface 59-2 Fahr. 



20 feet 58-2 



35 56"-0 



Loch Htrmidale (see Plate LXVIII.). Loch Hermidale is the middle 

 loch of the chain of three lochs which were surveyed in the Haka basin. It 

 is of irregular form, broadest in the middle and tapering to each end. Its 

 long axis, somewhat curved, runs nearly north and south. It is surrounded 

 by low moorland and has rocky shores. It receives the burns coming from 

 Loch Aiiscot and from many little lochs to east and west, and overflows 

 into Loch na Deighe fo Dheas. It is fully three-quarters of a mile long, 

 a quarter of a mile broad, and one-eleventh of a mile in mean breadth. 

 The broad central part of the loch forms a simple basin, with the 

 maximum depth of 41 feet; a lesser basin to the north is 16 feet deep in 

 the centre ; the long narrow part running south towards Loch Auscot is 

 irregular, with islands and boulders, and has various holes of from 15 to 18 

 feet deep. The mean depth is 12| feet. The superficial area is 54 acres, 

 and the volume 29 millions of cubic feet. The drainage area, which 

 includes Loch Auscot and many smaller lochs, is just about a square mile. 

 On June 30, 1904, the surface was 8*7 feet above the sea. The tempera- 

 ture was almost uniform throughout, viz. 



Surface 59-2 Fahr. 



20 feet 59-0 



35 58-8 . 



LocJi na Deirjhe fo Dheas (see Plate LXVIII.) is the northernmost 

 loch of the Haka basin surveyed, lying close to the base of Rueval, the 

 highest hill in Benbecula, on its east side. It is of comparatively simple 

 oblong form, its long axis running north and south. There is a consider- 

 able inflow from lochs both to north and south. The outflow is by a 

 stream half a mile long, issuing from the east side into the Oban Haka, a 

 branch of Loch Uskavagh. The surrounding country is low moorland, 

 except where Etieval rises to the west, the shores almost entirely rock, here 

 and there covered by mounds of gravelly debris with boulders. The out- 

 flowing stream is bounded by rocks on both sides The loch is fully half 

 a mile long by a quarter of a mile broad, with a mean breadth of one- 

 eighth of a mile. The basin is a simple one, with the maximum depth of 34 

 feet near the centre, and the bottom sloping gently to the centre. The 

 southern bay is nearly flat and about 8 feet deep. The long inlet running 

 north has a depth of 9 feet at its mouth and 18 feet within. The mean 

 depth is Ki feet. The area of the surface is 52 acres, and the volume of 

 water 24 millions of cubic feet. The drainage area is Ij square miles. 

 On June 30, 1904, the surface was 7'5 feet above the sea. The tempera- 

 ture varied only 0*2 of a degree from the surface, which was 59'7 Fahr., 

 to a depth of 30 feet. 



