THE FRESH-WATER LOCHS OF SCOTLAND. 



403 



diameter, is fully half a mile, the mean breadth being over one-third of 

 a mile. The superficial area is about 131 acres, and the contents 136 

 millions of cubic feet. The drainage area is rather over 1 square mile. 

 Some small burns come in from the hills to the north, and the overflow 

 is carried into the Doe burn, a mile to the south-west, and so into 

 Loch Ness. 



Loch Tarff is shallow. Though it has a maximum depth of 89 feet, 

 the mean depth is only 24 feet, nearly two-thirds of the area being less 

 than 25 feet deep. The bottom is irregular, there being three separate 

 basins over 25 feet in depth. Two of these are unimportant and lie 



FIG. 62. LOCH TABFF, LOOKING NORTH-EAST. 



It i/ Mr. <r. West. From " Proc. Roy. Soc. Eilin.," \>y perini**ion of the Council.) 



towards the south-east shore, with maximum depths of 27 and 42 feet 

 respectively. The largest 2 5 -feet area lies to the north-west of Eilean 

 Ban, and stretches from south-west to north-east nearly across the loch, 

 with a breadth of one-fifth of a mile. It encloses a small 50-feet area 

 and a very small area of over 75 feet, both to the north of the centre 

 and nearer the north-east shore, the maximum sounding, 89 feet, being 

 found about half-way between the island and a rocky point north-west 

 from it. 



Temperature Obxeri'atinnsi. A series of temperatures taken in the 

 deep part on April 25, 1903, showed a range of only 1| degrees, as 

 shown in the following table : 



