I50 THE HABITS OF THE SALMON. 



Others, if not discharged into rivers in excessive 

 quantities are, comparatively speaking, harmless. 

 Sewage matter, for instance, is of a nature the least 

 injurious, and my opinion is based on the fact that 

 the biggest trout, in the finest condition, are to be 

 found at a point directly below where sewage is 

 discharged into a river. Refuse from tin, chemical, 

 and gas works, washings from lead-mines and flax 

 water, are all fatal to fish life, if the dose is strong 

 enough ; but it appears that what is enough to kill 

 small and immature fish, is not enough to prove fatal 

 to adult salmon. Not many years ago, when visiting 

 the banks of the Dovey in North Wales, at Machyn- 

 lleth, I noticed on a certain Saturday several small 

 sewin (sea-trout) being carried down the river, appa- 

 rently dyings On my asking a local professional what 

 ailed these fish, he informed me that every Saturday 

 washings from the lead-mines situated a little distance 

 above, which had accumulated during the week, were 

 let go into the river, killing most of the smaller fish, 

 but producing no more apparent effect on the salmon 



