How to obtain it. 157 



Where any fresh concrete work comes in contact with the 

 water I prefer running the latter over it for three months. Cement 

 is partially soluble, and in some waters more than in others. The 

 soluble portions are injurious to trout ova, but after being in use 

 for some time the whole becomes thoroughly seasoned, and is 

 then quite harmless. I am alluding now to such works as settling 

 tanks and aqueducts, for which concrete will often be found very 

 useful. It is a very good plan, after the water has been running 

 over new works for a few days, to turn it off and give the whole 

 a good scour out, and after a few more days repeat the process. 

 After this, turn on the water for good, and do not on any account 

 scour out again. Nature usually provides a coating for concrete 

 work in the shape of minute vegetable -growths, and these should 

 not be thoughtlessly removed. The same applies to concrete 

 ponds, with the exception that sometimes confervoid and other 

 growths begin to threaten trouble. They may then be gently 

 raked off or otherwise partially removed, but without any scraping. 

 The well-known proverb, " Do nothing rashly," certainly 

 applies in fish culture, and it is well to observe it. It often 

 happens that mistakes are seen when too late, which by a little 

 forethought might have been avoided. 



A day or so before spawning, a sufficient number of grilles 

 should be placed in position for receiving the ova. They are 

 usually stacked away in some convenient place, and are all ready 

 for use. Dust them if they require it, and wash them well before 

 placing them in the hatching boxes. It is well to keep them 

 submerged in some tank for a few days, and finally to wash them 

 under a tap. They are then ready for work and may be placed 

 in position. On putting them into the hatching boxes, let one 

 side go right to the bottom and shake them gently. This causes 

 the glass tubes to fill with water. Then, without taking them out, 

 lay them on their rests. They have a tendency to float at first ; 

 but this is easily counter-balanced by placing a piece of lead on 

 each end of the grille. These weights may be fixed or loose, and 

 I prefer them loose, and use neat little cubes of lead specially cast 

 for the purpose. Small blocks of stone will do perfectly well, or 

 even stones out of a brook. 



When a box is commenced with it should always be filled 



