FOR PLEASURE AND PROFIT. 



17 



be usied in place of the contrivance ; but so arrange it, if 

 possible, that a fall occurs at this point, for there is nothing to 

 be gained by having toi put ai screen there, and it is a rule 

 without exception to have as few screens as possible in any 

 fishery, as, even under most favourable conditions of fixing 

 and situation, they invariably require some attention, aind 

 the saving of laibour is a consideration at every fishery ; F F P 

 is the surplus water channel, which be sure to have cut deep 

 enough. The sluice at D D is for the purpose of disposing of 

 any debris that may accumulate against the screen c. All 

 these matters will be explained fully in their proper place. 



Fig. 3. Method of Constructing Redds off a River. 



The direction of the current is> shown by the arrows. The 

 working of the arrangement is quite simple. The use of the 

 screens I have already explained (and they will be referred to 

 aigain when I am dealing with rearing the young fish). The 

 sluice at D is adjusted so that sufficient, and only sufficient, 

 water passes over the redds, the surplus being conducted down 

 the channel F F F and so out into the main stream at E. In 

 this manner the redds are guarded against any but a most dis- 

 astrous flood, and they should not be formed, at all where such 

 a flood is likely to occur. Of course, the outlet E may occur 

 at any point lower down, as most convenient; indeed, it 

 should be lower down than shown ; and equally, of course, the 

 series of redds may be longer or shorter, and, indeed, there 



