THE FRESH-WATER LOCHS OF SCOTLAND. 383 



was determined from bench-marks as being 52-6 feet above the sea, 

 and to this datum-level all soundings have been reduced. A levelling- 

 staff was erected first at Fort Augustus, then at Invermoriston, Foyers, 

 and Temple piers, and the height of the water on this staff was read 

 daily during the progress of the survey, so that the variations in level 

 from day to day, and the variations from the starting-point, were readily 

 known. These staff readings showed that the water fell gradually but 

 irregularly, and by April 15 it was 1 foot lower, and by the 18th it was 

 H feet lower, than on April 1. 



Loch Ness proper may be said to extend from the head of the 

 loch at Fort Augustus to the narrows at Bona ferry, a distance of 22 j 

 miles following the axis of maximum depth. This figure is inferior 

 to the length of Loch Awe (25 \ miles), and slightly in excess of the 

 length of Loch Lomond (22 miles) ; if we regard the small basin of 

 Loch Dochfour, which is continuous with Loch Ness at its northern 

 end, as forming part of the loch, then the total length from the exit 

 of the river Ness to the head of the loch, is about 24J miles. 



In this place it is proposed to include Loch Dochfour in dealing with 

 Loch Ness ; it is a basin about 1 \ miles in length, with a maximum 

 depth of 50 feet in the wide central portion, whence it narrows towards 

 the two ends, the southern narrows leading into Loch Ness, and the 

 northern termination being divided into two branches, the eastern 

 branch forming the river Ness, and the western branch the continuation 

 of the canal. With a strong south-westerly wind there is a surface 

 current from Loch Ness into Loch Dochfour through the narrows at 

 Bona ferry, and, if long continued, the water becomes banked up in 

 Loch Dochfour, and gives rise to a return current along the bottom into 

 Loch Ness ; with a strong wind from the north-east the surface current 

 sets in the opposite direction, i.e. from Loch Dochfour into Loch Ness. 

 Cut off from the western margin of Loch Dochfour, by embankments 

 carrying the towing-path for the canal, are two small basins, one called 

 Abban water, having a maximum depth of 9 feet, the other without a 

 distinctive name, having a maximum depth of 23 feet; they stand at 

 the same level as Loch Dochfour, the water evidently percolating 

 through the embankments. 



Loch Ness may be said to be fairly uniform in breadth, though 

 varying to some extent, but on the whole its shore-line is very regular 

 when compared with other large lochs. The upper portion between 

 Fort Augustus and Foyers for about 10 miles is under a mile in width, 

 except at the opening of Glen Moriston, where the breadth slightly 

 exceeds a mile. The portion between Foyers and Castle Urquhart for 

 about 5 miles is almost exactly a mile in width, while the lower portion 

 between Castle Urquhart and Torr point for about 5 miles exceeds a 

 mile in width. The widest part of the loch is at Urquhart bay, from 

 the mouth of the river Enrick due east to the opposite shore, where the 



