THE FRESH- WATEE LOCHS OF SCOTLAND. 
159 
east to west exceeding a mile, the maximum breadth being two-thirds of 
a mile. The superficial area exceeds 300 acres, or nearly half a square 
mile, and the drainage area is large — exceeding 17 square miles. The 
maximum depth of 49 feet was recorded comparatively close to the east 
shore, whence the water shoals gradually towards the west, the western 
portion of the loch being very shallow ; nearly 60 per cent, of the entire 
lake-floor is covered by less than 10 feet of water. The volume is estimated 
at 192 million cubic feet, and the mean depth at nearly 15 feet. The loch 
was surveyed on October 10, 1903, when the elevation was 1045*0 feet above 
sea-level, as compared with 1045*8 feet determined by the officers of the 
Ordnance Survey on August 16, 1866. The temperature of the surface 
water was 49°*1 ,Fahr. 
Loch PMtiulais (see Plate LX.), a small but relatively deep loch, lies 
less than 2 miles north-east of Aviemore, and about 3 miles north-west 
from Loch Morlich. The loch is over half a mile in length from north 
to south, and a quarter of a mile in maximum breadth, covering an area 
of about 67 acres, and draining an area of about 2^ square miles. The 
maximum depth of 74 feet was observed approximately near the centre 
of the loch, but towards the northern end, the basin being simple in con- 
formation. About 69 per cent, of the lake-floor is covered by less than 
25 feet of water. The volume is computed at 67 million cubic feet, and 
the mean depth at over 23 feet. The loch was surveyed on October 12, 
1903, when the elevation was found to be 674*3 feet above the sea; the 
Ordnance Survey map gives the elevation as 673*9 feet, but the date when 
levelled is not indicated. Temperatures taken in the deepest i^art of the 
loch showed a range from surface to bottom of only Fahr. ; — 
Surface 
10 feet 
20 „ 
30 „ 
40 „ 
50 „ 
70 „ 
50°-0 Fahr. 
49°-8 „ 
49°-8 „ 
49-°6 „ 
49°-6 „ 
49°*4 „ 
49°*4 „ 
Loch Builg (see Plate LXI.) lies nearly 20 miles east of Aviemore, 
and about 6 miles north-west from Balmoral castle, in a valley running 
north and south between Glen Avon and the head of Glen Gairn. A 
small proportion of the overflow finds its way into the river Gairn, and 
thence into the river Dee, as already stated ; but the normal outflow is to 
the north, by the Builg burn and the river Avon, into the river Sj 3 ey. 
The reader is referred to the paper by Drs. Johnston and Collet, already 
cited, for some remarks on the formation of Loch Builg. The loch is less 
than a mile in length, by a quarter of a mile in maximum breadth, the 
superficial area being about 77 acres. The maximum depth of 86 feet was 
observed approximately in the middle of the loch. The volume of water 
