THE FRESH-WATER LOCHS OF SCOTLAND. 199 



Loch na Ceithir-Eileana (see Plate LXXV.). The higher of the two 

 lochs of this basin which lie between Loch Oban nam Fiadh and Loch 

 Obisary. It is of somewhat simple outline among the lochs of Uist, and 

 somewhat rhomboid. It is half a mile long by one-third of a mile broad. 

 The bottom is uneven, and, as the name implies, four islands rise above 

 the surface. The two larger islands are on a ridge which runs south-west 

 and north-east, the depths between them and the shores varying from 7 to 

 9 feet. In the basin east of them, of triangular form, the maximum depth 

 of 42 feet occurs quite close to the shore at the east end, and another 

 sounding of 39 feet is close inshore on the south. West of the larger 

 islands is a deep furrow, where a depth of 37 feet was found. This is the 

 highest loch in the Oban nam Fiadh basin, the surface being 16'85 feet 

 above sea-level on June 7, 1904. 



The range of temperature was great, amounting to 12*6 throughout 

 the body of water, the greatest fall being observed between 20 and 25 feet, 

 a fall of 5", or one degree per foot of depth, as shown in the following 

 table : 



Surface 64-6 Fahr. 



5 feet 63-0 



15 61-0 



20 58-0 



25 53^-0 



35 52^-0 



Loch na Coinmch (see Plate LXXV.). A little triangular loch, half 

 a mile long, between Loch na Ceithir-Eileana and Loch Oban nam Fiadh. 

 The shores are of rock and the bottom stony. The bottom is very uneven, 

 and the maximum depth of 25 feet is found in the centre of the loch, close 

 to and between two heaps of stones. The surface on June 7, 1904, was 

 only 9-9 feet above sea-level. The range of temperature was here also 

 very high, nearly 16 degrees in the 25 feet of water, the fall between 

 15 and 20 feet exceeding one degree per foot of depth, as shown in the 

 accompanying table : 



Surface 68-0 Fahr. 



10 feet 63-0 



15 62-6 



20 57'0 



25 52-3 



Loch Tormasad (see Plate LXXI.). A narrow and shallow loch, 

 measuring two-thirds of a mile long by one-third in greatest breadth, 

 which lies just west of the head of Loch Eport, into which it drains by 

 a burn half a mile in length. The southern part forms an equilateral 

 triangle, the centre of which is occupied by a low island, joined to the 

 shore by a causeway. The bottom is nearly level, about 7 feet deep, with 

 depressions of 9 and 10 feet. 



