44 FISH HATCHIHra, 



that from those left to their natural course 

 there would not have been so many. fecun- 

 dated eggs from the 310 as we have in the 

 breeding-boxes from the forty fish. All 

 these fish were caught on one ford where the 

 Almond joins the Tay." 



Then again, we have the reverse of floods 

 — we have droughts ; and the nests made 

 when the water is liigh become bare and 

 exposed to the air when the water goes 

 down ; either the eggs die from this cause, or 

 else the young when hatched out, having no 

 water, "refuse to exist." 



I have seen a shallow ditch leading out of 

 Ruislip Reservoir one mass of dead fry of 

 roach, dace, and jack, the water having been 

 let "out for the canal. ; 



Nor must we forget mill-wheels. Here is 



