54 
BATHYMETRICAL SURVEY OF 
Feet. 
Acres. 
Per cent. 
0 to 25 
74 
54 
25 „ 50 
45 
33 
Over 50 
18 
13 
137 
100 
Temperature Observations . — The following series of temperatures taken 
in the deepest part of the loch at 5 p.m. on the date of the survey 
shows (as in the case of Dubh Loch) a uniform temperature in the upper 
layers of water, with a maximum fall beyond the depth of 50 feet : — 
Surface ... 
55°-3 Fahr. 
5 feet . . . 
.L 
55°-3 „ 
10 „ ... 
55°-3 „ 
20 „ ... 
55°-3 „ 
30 „ 
54°*9 ,, 
50 „ ... 
54°-0 „ 
60 „ 
... 
_ 51°-8 „ 
Here the total range is only 3° *5, and the fall of temperature between 
50 and 60 feet 2°'2 ; while in Dubh Loch the range was larger, the surface 
temperature being higher and the bottom temperature lower, and the fall 
of temperature greater, than in Loch Bad an Sgalaig. 
Loch a’ Bhealaich (see Plate XIX.). — Loch a’ Bhealaich (or Yallich) lies 
less than a mile to the south-west of Loch na h-Oidche, and is almost 
continuous with Loch a’ Ghobhainn, the stream flowing from Loch a’ 
Bhealaich into Loch a’ Ghobhainn being only about 200 yards in 
length. Loch a’ Bhealaich trends in a west-north-west and east-south- 
east direction, and is 1| miles in length, varying considerably in width, 
the maximum width being less than half a mile, while the mean breadth of 
the entire loch is a quarter of a mile. Its waters cover an area of about 
279 acres, or nearly half a square mile, and it receives the drainage 
from an area of 5 square miles. The maximum depth of 92 feet was 
observed near the middle of the wide eastern portion, about a quarter 
of a mile from the east end of the loch and towards the northern shore. 
The volume of water is estimated at 398 millions of cubic feet, and the 
mean depth at 32| feet. The loch was surveyed on August 8, 1902, but 
the elevation of the lake-surface above the sea could not be determined. 
Loch a’ Bhealaich is complex in conformation, including three deep 
basins exceeding 50 feet in depth, separated by shallower water, the 
shoalings coinciding with constrictions in the outline. The largest and 
deepest basin is contained in the wide eastern portion of the loch, where 
there is a 50-feet area nearly half a mile in length, by a quarter of a mile 
in maximum width. Separated from this eastern basin by a short interval, 
in which a maximum depth of 40 feet was observed, is a small central 
50-feet area, based on soundings in 51, 55, and 55 feet, a quarter of a mile 
in length. This central area is separated by a longer interval, in which a 
