1904 - 5 .] Study of the Lakes of Scotland and Denmark. 411 
ing the moss-covered precipitous mountain sides. I have been told 
that Loch Morar, the deepest of all Scottish lakes, has the clearest 
water, Forel’s disc being visible at a depth of 44 feet ; and in this 
connection it is of great interest to note the fact that the rocks 
along the shores of Loch Morar and all over the drainage area are 
not covered with peat and mosses, but are for the most part quite 
bare. As far as I know, we have no particularly peaty water in 
any of our larger lakes, though it is, of course, a very common 
feature in the smaller lakes surrounded by peat, and whose floors 
are covered by peaty mud, many of which are quite artificial, 
being due to the digging of peat. 
The foregoing remarks refer only to the character of the Danish 
and Scottish lakes, but I feel convinced that many of the facts 
stated are common to lakes belonging respectively to the great 
Central European plain and to alpine countries. As traits common 
to all the first-mentioned lakes, I would specially point to their 
shallowness, their gently sloping shores, their roundish outline, the 
high temperature of the surface water in summer and the freezing 
over in winter, the ice-erosion on the shores, the small trans- 
parency, and the yellow or yellow-green colour of the water in 
summer, due to the huge plankton-masses. Differences may be 
looked for with regard to the chemical composition of the water 
and bottom-mud, owing to the varying chemical composition of 
the soil in different countries ; I anticipate that further investiga- 
tions will prove that the large amount of lime carried by streams 
into our lakes is one of the most characteristic peculiarities of the 
Danish lakes. On the other hand, I am of opinion that the 
features mentioned in connection with the Scottish lakes are 
common to alpine lakes in general. Especially would I call 
attention to their great depth and long and narrow form, their 
precipitous shores, the sudden flooding of the rivers and the rapid 
changes in the level of the lakes, and the slight amplitude in the 
annual variation of the surface temperature. Peculiar to the 
Scottish lakes are the small transparency and yellowish-brown 
colour of the water, to which may undoubtedly be added the 
large amount of humic acid. These peculiarities may be traced to, 
and are closely connected with, the strongly-marked climatological 
and geological conditions common to the whole country. 
