26 BATHYMETRICAL SURVEY OF 







20 fathoms the temperature has not been appreciably affected. In June, 

 1898, the whole body of water in the loch was apparently slightly 

 warmer than in the previous June. The November curve shows a great 

 accumulation of summer heat in the layers down to depths of 30 and 35 

 fathoms. By this time cooling has set in, and progresses slowly until 

 the spring, when the whole of the layers assume the nearly uniform 

 temperature indicated by the April curve. The temperature of the 

 bottom of the loch in depths of 400 feet may vary one or two degrees 

 from year to year, this variation being due to the strength of the winds 

 and general character of the climate in different years.* The highest 



56 



o 

 55 



5* 

 53- 



o 



52 



c 

 51- 



4-8- 



Temperature of LOCH KATRINE 



i i 

 1 



APRIL 1899 



JUNE 1897 



JUNE 1898 



.NOVEMBER 1897 



3 5 10 15 2O 25 30 35 4-O 45 5O 55 6O 65 7O 75 80 82/ 



TAT H O M S 



PIG. 13. CURVES OF TEMPERATURE IN LOCH KATRINE. 



temperature recorded in Loch Katrine is 58-4, so that the range in the 

 central parts of the loch throughout the whole year is probably about 

 18 Fahr. 



* See Murray, " Some Observations on the Temperature of the Water of the Scottish 

 Fresh-water Lochs" (Scottish Geographical Magazine, vol. xiii. p. 1, 1897). At noon on 

 March 10, 1900, in calm and frosty weather, the temperature of the surface water of 

 Loch Katrine, over the deepest part of the loch, was 40-3, at 10 feet 40-2; at all other 

 depths down to 492 feet the temperature-readings were 40-0 and 40 1. On the same 

 date the readings in shallow water were 39 -4. 



