THE FRESH-WATER LOCHS OF SCOTLAND. 
221 
minutes and 1 minute respectively, that the whole effect was extremely 
complicated, and no calculations could be made from the observations. 
Temperature Observations . — The temperatures taken in Lochan Fada 
are extremely interesting, because they indicate a much lower tempe- 
rature than was observed in any of the other lochs in the district at the 
same time of the year, as shown by the following series taken at 6.40 
p.m. on July 28, 1902, to the south of Allt Meallan a’ Chruidh : — 
Surface 
10 feet 
20 „ 
50 „ 
75 „ 
100 „ 
150 „ 
220 „ 
1 Fahr. 
1 „ 
1 » 
C ,, 
0 „ 
3 „ 
51° 
51° 
51° 
45° 
45° 
44° 
44° 
This series indicates an almost constant temperature down to 50 
feet, then a fall of 5°'2 between 50 and 75 feet (a fall exceeding 1°*0 per 
5 feet of depth), and then a slight decrease of l°-7 down to the bottom in 
220 feet. Compared with the larger and deeper Loch Maree, the water 
in Lochan Fada was found to be colder at all depths than that in Loch 
Maree ; thus the surface of Lochan Fada had a temperature about 3 
lower than was observed in the surface waters of Loch Maree a week 
earlier, and at the bottom of Lochan Fada, in 220 feet, the temperature 
was found to be about 1|° lower than at the bottom of Loch Maree in 
350 feet. This is probably due to the fact that Lochan Fada is very 
deep, considering its area, and therefore a large volume of water has to 
be warmed, while only a comparatively limited area is exposed to the 
heating agencies. 
Loch Garhhaig (see Plate XLVI.). — Loch Garbhaig lies between 
Lochan Fada and Loch Maree, about half a mile from the former and 
miles from the latter. It drains into Loch Maree by the Amhainn 
na Fuirneis, which leaves the loch at its western end, and, flowing in a 
westerly direction, enters Loch Maree between Furness and Letterewe. 
The ground at the eastern end is not much elevated above the surface of 
the loch, the col leading over to Lochan Fada, but on the south side 
Slioch rises up from the shore to a height of 3200 feet, and on the north 
side the high ground to the east of Beinn Lair rises to over 2500 feet. 
The most noticeable feature of the surrounding country is its bareness. 
The height of the loch above the sea was not determined by levelling 
when surveyed on July 25, 1902, but from the contour-lines the level 
is probably between 1005 and 1015 feet. 
Loch Garbhaig is over a mile in length, with a maximum breadth 
of nearly one-third of a mile, the mean breadth being one-fifth of a 
mile. Its waters cover an area of about 148 acres, and it drains an 
