THE FRESH-WATER LOCHS OF SCOTLAND. 27 



Loch Arklet. 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. 



LochAchray. 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 0< 1, 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-l 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 Voil. 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 0> 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 0> 4, and a little distance 



