5 2 Proceedings of Royal Society of Edinburgh. [skss. 
kept. The readings were not taken with any precise accuracy, 
degrees only being given. It may, perhaps, be of interest to note 
that during at least the months of January and February the tem- 
perature of Talla Water seems to be higher than that of Tweed. 
The same thermometer was used in both cases, the observer walking 
from one stream to the other, yet, as a rule, the water of Talla is 
recorded as the higher by 2°. Only on one occasion do I find the 
reverse to be the case, the readings being, Tweed 40°, Talla 39° 
(14th Feb.). The few instances of the readings being the same 
occur chiefly when the air temperature is at or below freezing point. 
In no case, when comparing temperatures with records of 
ascending fish, do I find evidence which leads me to suppose that 
particular fluctuations of temperature have any effect upon the 
movements of the fish. This negative result is, I think, of some 
interest, since the effect of a change of temperature in a tributary, 
as compared to a main stream, has been considered by some as of 
great importance. 
The following is a record of the temperatures, which may be 
compared with the above table as to arrival of fish : — 
Water Temperatures op Tweed and Talla, taken daily from 
17th January to 15th February 1897. 
Tweed. 
Talla. 
Tweed. 
Talla. 
32 
34 
33 
36 
32 
33 
33 
36 
33 
35 
33 
35 
33 
35 
33 
35 
32 
34 
33 
35 
32 
34 
33 
35 
32 
32 
35 
37 
32 
34 
35 
37 
32 
32 
35 
35 
32 
32 
36 
38 
32 
32 
36 
38 
32 
32 
33 
36 
32 
34 
37 
39 
32 
35 
40 
39 
32 
36 
40 
40 
