80 BATHYMETRICAL SURVEY OF 



43-5. A series of temperatures was taken below the surface at 1 p.m. 

 on April 24, 1902, in 102 feet of water, with the following results: 



Surface 43%5 Fahr. 



5 feet 43 v> ,, 



10 43 '4 



20 43 -2 



50 43-0 



70 42-6 



100 42-4 



showing a gradual decrease of temperature from surface to bottom, the 

 range of temperature being 1 0> 1 in the 100 feet of water. 



Loch Tay (see Plates XXIV. and XXV.). Loch Tay is one of the 

 largest of the Scottish fresh-water lochs, unsurpassed in the beauty of 

 its surroundings, and well known to anglers on account of its salmon 

 fishings, which are among the best in Scotland. It is also a good trout- 

 fishing loch, having been much improved within recent years by being 

 stocked with Loch Leven trout. The scenery around the loch is very 

 fine grand and wild towards the south-west end, with the mighty Ben 

 Lawers rising from its northern shores about half-way down the loch, 

 becoming more sylvan in character towards the north-east end, a 

 splendid view presenting itself to the eyes of a spectator from Kenmore 

 Bridge (see Fig. 24). 



Loch Tay is the largest loch in the basin of the river Tay, though 

 Loch Ericht is a very formidable rival for this distinction, as will be 

 seen from the following comparison : 



This comparison shows that the maximum depth observed in Loch 

 Ericht slightly exceeds that observed in Loch Tay, but in all other 

 respects Loch Tay has the advantage, though as regards length and 

 maximum breadth the two lochs are almost identical. 



Loch Tay is over 14J miles in length, and over one mile in maximum 

 breadth, the mean breadth being nearly three-quarters of a mile, or 

 nearly 5 per cent, of the length. Its waters cover an area of over 6500 

 acres, or over 10 square miles, and it drains directly an area of about 

 187J square miles, but since it receives the outflow from Lochs Dochart 

 and lubhair, its total drainage-area is over 232 square miles, or nearly 



