76 
BATHYMETRICAL SURVEY OF 
the soundings taken by different surveyors. Mr. Grant- Wilson took 
over 180 soundings in 1888, Sir John Murray and the late Mr. F. P. 
Pullar took about 150 soundings in 1900, and the Lake Survey took 500 
soundings in 1902, but in no case was the depth found to exceed 288 
feet. On the accompanying map only the Lake Survey soundings are 
laid down, and the contour-lines drawn in from them. 
Loch Earn is 6 J miles in length, and four-fifths of a mile in maximum 
breadth, the mean breadth being three-fifths of a mile, or 9J per cent, 
of the length. The waters of the loch cover an area of over 2400 
acres, or nearly 4 square miles, and it drains an area of over 54 J 
riG. 22. LOCH EARN. 
(Photograph by J. Parsons, B.Sc.) 
square miles — an area fourteen times greater than the area of the 
loch. Five hundred soundings were taken in Loch Earn, the maximumi 
depth observed being 287 feet, which agrees very well with the 
maximum recorded by Mr. Grant-Wilson in 1888, viz. 48 fathoms, 
or 288 feet. The volume of water contained in the loch is estimated 
at 14,420,638,000 cubic feet; and the mean depth at 138 feet, or 48 
per cent, of the maximum depth. The length of the loch is 118 times 
the maximum depth, and 245 times the mean depth. - 
Loch Earn forms a simple basin, the lake-floor sinking gradually on 
all sides down to the greatest depth, as is well shown by the longitudinal 
and three cross-sections on the map. The 50-feet contour-line follows 
