THE FRESH-WATER LOCHS OF SCOTLAND. 273 



portion of the loch between Port-in-Sherrich and Inistrynich a stretch 

 of over 12 miles in length is less than 20o feet in depth, the deepest 

 sounding recorded between these two places being 196 feet. The 300- 

 feet contour encloses an area about 1J miles in length, less than 5 miles 

 from the head of the loch, two soundings at the maximum depth of 307 

 feet being recorded about half a mile apart. 



The following table, giving the approximate areas between the contour- 

 lines drawn in at intervals of 100 feet, and the percentages to the total 

 area of the loch, shows that considerably more than one-half of the lake- 

 floor is covered by less than 100 feet of water : 



Feet. Acres. Per cent. 



to 100 5474 ... 57-6 



100 200 2900 ... 30-5 



200 300 1017 ... 10-7 



Over 300 114 ... 1-2 



9505 100-0 



Temperature Observations. During the progress of the survey four 

 series of temperatures were taken, which showed a total range throughout 

 the whole body of water of only 3J Fahr., as given in the following 

 table : 



SERIAL TEMPEBATUBEB IN LOCH AWE. 



DM Lochan (see Plate CXXVI.). The name Dubh Lochau is applied 

 to four little lochs lying about a mile south-east of Kingshouse. They 

 are all weedy, and only the one lying farthest to the south-east was 

 surveyed. It takes the form of a V with one limb pointing to the north, 

 the other to the north-west. The length is a little over a quarter of a 

 mile, and the superficial area about 17 acres. The maximum depth of 

 10 feet was found abont 150 yards from the end of the north limb. The 

 volume of water is estimated at 2 million cubic feet, and the mean depth 

 at nearly 3 feet. Dubh Lochan was surveyed on May 21, 1903, but the 

 level could not be determined ; the elevation given on the Ordnance Survey 



T 



