10 THE SALMON. 



der to breed in their natal waters. This is an in- 

 stinct beyond the power of naturalists to explain ; 

 indeed it is but little, with all their boasted know- 

 ledge, that they can read, in nature's " infinite book 

 of secrecy." There are, however, some instances 

 of animals mistaking their instinct. The flesh-fly 

 has been seen to deposit its eggs in the flower of 

 the fetid stapelia, being deceived by the resemblance 

 of its smell to that of carrion. So we have known 

 salmon run up rivers in which they were not bred ; 

 however, this is a circumstance which rarely hap- 

 pens. 



HABITS. 



Salmon delight in rivers which have alpine 

 sources. They prefer to all others a gravelly, pebbly 

 bottom, where there are large stones clear of every 

 kind of slime. They avoid waters or streams 

 flowing upon mundic ore, or that are impregnated 

 with calcareous or selenetic particles. They are 

 impatient of shade unless in the very heat of sum- 

 mer, and dislike to remain for any length of time 

 in such parts of rivers where the banks are wooded, 

 or near hanging rocks that exclude the sun from the 

 pool. They are extremely sensible of approaching 

 changes in the weather ; they then leap above the 

 water, and apparently enjoy the prospect of coming 

 rains and showery winds. Immediately before, and 

 in the time of thunder, they keep close to the bot- 

 tom, and are seemingly affected by every concussion 

 of the air. They always lie with their heads point- 



