THE SALMON AND WATER TEMPERATURE 131 
With regard to the west coast rivers, which were 
supposed to be colder in the early months of the year, 
I may cite first the Laxford in west Sutherland. I 
have complete readings from this river, taken in 
1880, and am therefore able to compare it with the 
Helmsdale, Brora, and Shin in east Sutherland in 
1880. The Laxford flows out of Loch More, is con- 
sidered the finest salmon river of the North-West 
Highlands, but is late. A comparison of the daily 
means of those rivers shows that the Laxford is sub- 
ject to rapid fluctuations, as the Helmsdale is, and in 
this respect differs somewhat from the Brora and 
Shin. The latter, it must be recollected, has a very 
large reservoir at its head in the shape of Loch Shin, 
while the actual readings for the former were taken 
at a constriction of Loch Brora. When, however, 
curves are plotted representing the daily means of 
each river,* it is noticeable that they do not separate 
from one another in any marked way, and that the 
inclination of the Laxford curve, the western late 
river curve, is very similar to that of the Brora 
curve. In other words, the temperature conditions 
ascertained to exist in the Laxford are very similar 
indeed to the temperature conditions of the three 
early east coast rivers with which it is compared. 
The great advantage of being able to. compare 
late and early rivers on opposite coasts of the same 
country in the same year is further enhanced by the 
fact that the Helmsdale, Brora, and Laxford are 
first-class natural rivers, each bearing a full stock of 
* Twentieth Annual Report, Fishery Board for Scotland, II. 
p. 12. 
