THE FRESH-WATER LOCHS OF SCOTLAND. 
27 
Loch ArTdet . — Temperature observations taken in the centre of Loch 
Arklet on June 11, 1897, gave a temperature at the surface of 55°-4, 
and at 5 fathoms 54°*4; on April 13, 1899, the surface temperature was 
42°'7. Temperatures as high as 61° have been recorded in this loch, 
so that the annual range probably exceeds 29°. 
Loch Achray . — Observations taken in June and November, 1897, and 
April, 1899, showed that the temperature of the surface waters varied 
from 41° in April to 59°*5 in June, the temperature in November being 
46°. An intermediate observation at 5 fathoms in the centre on June 
12, 1897, gave 53°’5. The highest reading recorded at the surface of 
this loch is 64°T, so that the annual range probably exceeds 32°. 
Loch Drunkie . — Observations taken on June 12, 1897, showed that 
the surface waters had a temperature of 57°, and an intermediate 
observation at 5 fathoms gave 52°-6. On April 14, 1899, the surface 
temperature was 42° '4. 
Loch Vennachar . — The temperature observations taken in June, July, 
and November, 1897, and April, 1899, showed that the temperature of 
the surface water varied from 41° in April to 56°-5 in June, the tem- 
perature in November being 46° to 47°, while the water of Blairgarry 
stream had a temperature of 42°*2. Serial observations in the centre 
of the loch on June 10, 1897, showed a gradual fall in the temperature 
from 55°*8 at the surface to 47°*2 at 15 fathoms; while on April 11, 
1899, the temperature was practically uniform from surface to bottom 
at 42°*5 to 42°-7. 
Loch Doine . — Observations taken on July 7, 1897, and April 10, 1899, 
showed that the temperature varied from 42° in April to 54° in July. 
Serial observations in the centre of the loch in July gave a temperature 
at the surface of 54°, falling to 52°T at 10 fathoms, while in April the 
temperature was found to be nearly uniform from surface to bottom, 
ranging from 41°-8 to 42°'6. 
Loch Toil , — Observations taken in July, 1897, and April, 1899, showed 
that the temperature of the surface water varied from 41°*2 in April to 
56°*5 in July. Serial observations taken on July 7, 1897, showed that 
in the centre of the loch the temperature at the surface was 55°-0, at 
5 fathoms 54°'0, and at 16 fathoms 54°‘5, while further down the loch 
the temperature appeared to be rather higher, viz., 56°-0 at the surface, 
and 55°-3 at 3 fathoms and 8 fathoms. Serials taken on April 10, 1899, 
showed that the whole body of water was practically uniform in tem- 
perature at about 42°. 
For the sake of comparison, a few surface temperatures were taken 
at the head of Loch Earn on July 6, 1897, the temperature of the loch 
varying from 48°"8 to 49°‘2, while that of the streams flowing into the 
loch was 52°-2. On the following day (July 7, 1897) the surface of Loch 
Voil near the shore had a temperature of 56°-4, and a little distance 
