18 



7. The sand and pebbles placed in the boxes must be 

 perfectly clear of earthy substances and dirt ; and if, on 

 opening them, there be any spoiled that is, white 

 eggs, they must be removed. 



VIII. 



Although in the operations described trout only has 

 been mentioned, the plan of the two fishermen is appli- 

 cable to every other description of fresh-water fish, as 

 well as to those which, though living partly in fresh-water 

 and partly in the sea, spawn in rivers. 

 It has been TRIED in France on 



Salmon ; 



Carp; 



Pike; 



Tench; 



Perch ; 



and on other descriptions. And each experiment has 

 been perfectly satisfactory. 



IX. 



To make experiments on the different sorts of English 

 fish, it will only be necessary to follow the very simple 

 directions already given; or if in one or two sorts any 

 slight modification should happen to be required, they 

 will be so self-evident as not to need description. As 

 for the time of operating, that, of course, varies accord- 

 ing to the species of the fish, and still more as to the 

 temperature of the water. On this point, local know- 

 ledge can be the only guide. 



Care must, of course, be taken to provide, in streams 

 or reservoirs, a sufficient supply of fish for the fish to 



