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 diflers 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. 



