THE HABITS OF THE SALMON. 45 



do so. Indeed, the progress they make upstream 

 at that tune of year is known to be very slow. 

 Later on, when the water gets warmer, they move 

 quicker, and in summer, when it is warnier still, they 

 travel faster than ever. In autumn they also 

 seem to move as fast as they can, but the pace is 

 not so great, because they are encumbered with 

 spawn, and in proportion as their burden becomes 

 developed, their pace becomes slower. By that 

 time the water has usually decreased in tempera- 

 ture, and that alone would have an effect in 

 retarding their progress. I calculate that early in 

 the spring the average pace salmon travel upstream 

 in rapid rivers is, at a rough guess, about one- 

 third of a mile an hour, one mile an hour in summer, 

 and a quarter of a mile an hour in autumn. In 

 rivers containing no rapids and no rough broken 

 water, in other words, rivers of a sluggish nature, 

 the rate of speed is proportionately greater ; but I 

 think the fastest average pace salmon travel in any 

 river is seldom, if ever, more than two miles an 

 hour. 



