970 Proceedings of Royal Society of Edinburgh. [sess. 
restricted flora occurs here that is not found in the other areas 
under consideration. 
We are not at present able to give a comparative analysis of 
several of the lakes under investigation. It may, however, be 
interesting to give that of Loch Baile a Ghobhainn at Lismore, 
by W. E. Tetlow, along with that of Lake Geneva as published 
by Forel. 
One litre (or one million parts) contains (parts or) milligrams : — 
Lake Geneva. 
Loch Baile a 
Ghobhainn. 
Sodium and potassium chlorides 
1*8 
3*725 
Sodium sulphate ..... 
15-0 
Sulphuric acid 
trace 
Ammonium sulphate .... 
trace 
... 
Ammonia ...... 
trace 
Calcium sulphate ..... 
47*9 
Basic calcium phosphate 
0-094 
Calcium nitrate 
i’-o 
Nitric acid ...... 
trace 
Calcium carbonate 
73*9 
151-161 
Silica ....... 
3*7 
2-635 
Lithium ....... 
trace 
Alumina and ferric oxide 
1-9 
Iron carbonate ..... 
1-158 
Magnesium carbonate .... 
1-414 
Organic matter and loss .... 
11*9 
30-913 
Total solids ..... 
157 parts in 
191 parts in 
one million. 
one million. 
I. The Plants. 
Regarding the purely aquatic vegetation no ambiguity can exist 
as to what constitutes an aquatic plant. With the semi-aquatic 
plants, however, there is considerable scope for personal equation 
on the part of the observer. 
In the following pages the application of semi-aquatic has been 
restricted to plants that one habitually finds preferring decidedly 
wet places, with leaves and flowers elevated in the air. Attention 
must be called to the fact that no search has been instituted 
for the so-called rare plants. The object in view is rather to 
present before the reader the dominant plants of the districts 
investigated. 
