THE FRESH- WATER LOCHS OF SCOTLAND. 361 



The following table gives the approximate areas between the 

 contour-lines laid down at intervals of 100 feet, with the percentages 

 to the total area of the loch, and shows a gradually decreasing area 

 with increasing depth : 



to 100 feet 1412 acres 



100 200 1257 



200 300 1073 ,, 



Over 300 , 253 , 



3995 ,, 100-0 



Through the kindness of Mr. Thomas Honeyman, factor to Cameron 

 of Lochiel, we have inspected a bathymetrical chart of Loch Arkaig, 

 based upon soundings taken in 1889 by an officer in the German army 

 named Sandier. The chart is drawn to the scale of 1 J inches to the mile, 

 and the soundings are given in fathoms. A comparison of Sandler's 

 map with the Lake Survey map shows that (1) Sandler's soundings are 

 much less numerous than those taken by the Lake Survey, and many of 

 his lines were taken in zigzag fashion instead of running at right angles 

 to the axis of the loch; (2) though there is a general agreement 

 between the two maps, the Lake Survey map shows as a rule rather 

 deeper water, position for position; for instance, taking the deepest 

 sounding on each of Sandler's lines, and placing it approximately on 

 the Lake Survey map, deeper soundings occur in the vicinity; thus 

 Sandler's deepest sounding in 55 fathoms (330 feet) approximates to the 

 Lake Survey maximum in 359 feet. 



Temperature Observations. The surface temperature in the centre 

 of the loch varied from 48'3 Fahr. to 51'5 during the three days of the 

 survey; near shore it reached 52-3 on June 13. A series taken in the 

 main basin on June 11 showed a range of 4-7 from the surface to 280 

 feet, the greatest variation being observed in the superficial layers of 

 water, as shown in the accompanying table: 



Surface 49 '4 Fahr. 



10 feet "... 48-9 



25 47'5 



50 46'5 



100 ,, 45-5 



150 45-0 



200 44-9 



250 447 



280 447 



Loch P attack (see Plate LXXXIX.). Loch Pattack (or Pattaig) lies 

 at a considerable elevation among the mountains which separate Loch 

 Ericht from Loch Laggan. It is only about 2 miles distant from Loch 

 Ericht, though it belongs to a different drainage system, draining by 



