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 
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. 
