THE FRESH- WATER LOCHS OF SCOTLAND. 57 



This series shows a total range of 1*9 from surface to bottom, the 

 npper layers of water being nearly uniform in temperature, while between 

 20 and 50 feet the fall was l-6. 



Loch Bad a' Chrbiha (see Plate XVIII.). Loch Bad a' Chrotha (or 

 Badachro) is a shallow expansion of the river, much overgrown with weeds, 

 lying within half a mile of the southern shore of Loch Gairloch. It is 

 irregular in outline and conformation, covering an area of about 44 acres, 

 and draining directly an area of about 7 square miles ; but since it receives 

 the overflow from Lochs a' Bhealaich, a' Ghobhainn, and Braigh Horris- 

 dale, its total drainage area exceeds 21 square miles an area three 

 hundred times greater than that of the loch. The maximum depth of 

 23 feet was observed in the north-eastern part of the loch. The volume 

 of water is estimated at 12 million cubic feet, and the mean depth at 6 feet. 

 The loch was surveyed on August 6, 1902, but the elevation of the lake- 

 surface above the sea could not be determined. The area of the lake-floor 

 covered by less than 10 feet of water is about 40 acres, or 90 per cent, of 

 the total area ; in five places soundings in depths exceeding 10 feet were 

 recorded, one of them exceeding 20 feet, i.e. the deepest sounding in 

 23 feet. The temperature of the surface water on the date of the survey 

 was 58-4 Fahr. 



