THE FRESH-WATER LOCHS OF SCOTLAND. 
81 
23 times the area of the loch. Nearly 1000 soundings were taken 
in Loch Tay, and the maximum depth observed was 508 feet. The 
maximum depth recorded by Mr. Grant-Wilson in 1888, when he took 
415 soundings in Loch Tay, was 85 fathoms, or 510 feet. The volume 
of water contained in the loch is estimated at 56,549,745,000 cubic feet, 
or over one-third of a cubic mile, and the mean depth at 199 feet, or 39 
per cent, of the maximum depth. The length of the loch is 151 times 
the maximum depth, and 386 times the mean depth. 
Loch Tay trends in a north-east and south-west direction, being 
slightly sinuous in outline, somewhat like the italic letter /, as was noted 
A ■ 
FIG. 24. LOCH TAY, FROM KENMORE BRIDGE. 
(Photograph by T. N. Johnston, M.B., C.M., F.R.S.E.) 
in the case of Loch lubhair, which flows into it. It is extremely simple 
in conformation, the bottom sloping gradually, without any pronounced 
irregularities, on all sides down to the deepest part, as is well shown 
on the longitudinal and cross sections on the map. The 50-feet basin 
approaches to within less than 400 feet from the south-west end and less 
than 800 feet from the north-east end, and is 14^ miles in length. The 
slope of the bottom is thus steeper at the south-west end than at the 
north-east end. In the former position a sounding of 65 feet was taken 
about 750 feet from shore, giving a gradient of 1 in llj, and in the 
latter position a sounding of 80 feet was taken about 1075 feet from 
shore, giving a gradient of 1 in 13^. The 100-feet basin extends from 
G 
