THE FRESH- WATER LOCHS OF SCOTLAND. 265 
of the loch, and the soundings show in certain places rather steep slopes 
both off the northern and southern shores. 
Temperature Observations . — In the following table are given the 
results of a series of temperatures taken in Loch a’ Chroisg on August 
22, 1901, by Mr. Clark, and of two series taken by the Lake Survey 
staff on August 1, 1902: — 
Depth in feet. 
August 22, 1901 
(R. M. Clark). 
August 1, 1902. 
^ mile from E. end 
of loch in 106 feet. 
August 1, 1902. 
Deepest part of loch 
in 156 feet. 
° Fahr. 
° Fahr. 
° Fahr. 
0 
58*2 
55 0 
54 0 
20 
58-2 
25 
53-7 
53-9 
40 
V 58 -0 
50 
53 T 
53-2 
60 
57-6 
75 
53-3 
51-0 
80 
.51-9 
53 2 
90 
50 ’5 
10(J 
48-5 
49-9 
49 -1 
120 
47*5 
150 
48-9 
The series taken in 1901 shows a range from surface to bottom 
amounting to 10°*7, whereas the two series taken in 1902 show a range 
of only 5° in each case, and an extreme range of 6°. The upper layers 
of water down to a depth of 60 feet were much warmer in 1901 than in 
1902, but between 60 and 100 feet the 1901 observations indicated a 
fall of 9° (viz., a fall of 5°-7 between 60 and 80 feet, and a fall of 3°*4 
between 80 and 100 feet), so that the temperature of the bottom layers 
of water beyond 100 feet was lower in 1901 than was observed at these 
depths in 1902. 
Seiche . — On August 19, 1902, between 4.30 and 5.30 p.m., a seiche 
was observed by Mr. James Murray within the shelter of the pier at the 
east end of Loch a’ Chroisg, a light west breeze blowing at the time. The 
amplitude was a quarter of an inch, and the period about 11 J minutes. 
Loch Gown (see Plate LVII.). — Loch Gown (or Ledgowan) lies about 
a mile to the south-east of Loch a’ Chroisg, and is also a good trout loch, 
but the fishing is preserved. It trends in a north-east and south-west 
direction, is very irregular in outline, and about IJ miles in length. 
Though it may at one time have formed a single lake, it is now divided 
into two distinct lakes having, at the time of the survey, a difference 
in level exceeding 2 feet. This separation has probably been brought 
about mainly by the deposition of material laid down by the Allt 
Mhartuin, and the passage between them is obstructed by weeds, 
so that it is impossible to row a boat from one loch to the other, except 
after heavy floods. The two lochs are nearly equal in superficial area, 
but the southern basin is much deeper than the northern one. 
