THE FRESH-WATER LOCHS OF SCOTLAND. 187 



Surface 61-0 Fahr. 



15 feet 54-4 



25 52-8 



35 52-5 



Loch Huna (see Plate LXXI.). The uppermost loch of the Scadavay 

 basin, and the highest, being 21*6 feet above sea-level. In outline it is less 

 irregular than most Uist lochs, and somewhat resembles Loch Hunder in 

 form. It is nearly a mile long and half a mile broad. The bottom is very 

 uneven, and there are many small islands. On one of the largest there is 

 a Dun, and a long causeway leads to the west shore. The loch is on the 

 whole very shallow. There is a hole 23 feet deep in the northern part, 

 and another, with the maximum depth of 25 feet, in the southern part. 

 Many boulders are scattered around, as well as in, the loch. The shores 

 are partly of rock, partly of mounds of gravel. 



On May 31, 1904, there was a difference of 6^ D between the surface and 

 bottom temperatures : 



Surface 64-0 Fahr. 



5 feet 61-0 



10 60-0 



20 57-5 



Loch na Moracha (see Plate LXXI.). A loch of somewhat simple 

 form, draining, through a barrier a few yards wide, into Loch nan Eun. 

 From the north end three narrow inlets diverge to north and east and 

 west. In these are some islands. The body of the loch has no islands 

 except close inshore, and is a simple basin. The 10-feet contour follows 

 the outline, but is closer to the shore on the north-east, showing that the 

 slope is steeper there. Within are two depressions: 19 feet near the 

 north end, and 20 feet near the south-east corner. The greater part of the 

 shore is of rock. The temperature on May 11, 1904, was nearly uniform 

 throughout, viz. 49-2 Fahr. at the surface, and 49'0 at 15 feet. 



Loch nan Eun (see Plate LXXI.). In length Loch nan Eun is 

 exceeded only by Loch Obisary and Loch Scadavay. Many lochs exceed 

 it in area and volume. It is a narrow loch, running from west to east, 

 and measures 2| miles in length, by half a mile in greatest breadth. 

 As the centre of the loch at the broadest part is occupied by a large 

 island, Eilean Buidhe, half a mile long, there is no breadth of open water 

 anywhere. The mean depth is only 8 feet, and, as in Loch Scadavay, the 

 deeper soundings, 31 feet, 20 feet, 24 feet, etc., were obtained in isolated 

 holes. The superficial area is half a square mile, and the volume of water 

 114 millions of cubic feet. The loch drains an area of 4 square miles, 

 which includes Lochs Huna and na Moracha. Besides Eilean Buidhe 

 there are many smaller islands, and innumerable stones obstruct the 

 channel, especially in the western part and to the south of Eilean Buidhe , 

 where it is difficult to get about in a boat. 



