66 flow to obtain tt. 
The next question is—What is the best kind of screen? There 
are several important points to notice. 
(1) A screen should fit well into its place. 
(2) It should be strong. 
(3) It should be well let into the bank at each side, and 
especially underneath, so that the water cannot by 
any means flow round it or underneath it. 
(4) It should be large enough. 
(5) It should be so constructed that it will not allow any 
fish to escape. 
Only on very rare occasions have I come across screens that 
possessed all these qualifications. In travelling about the country 
inspecting ponds and lakes, I have not found one piece of water 
in fifty to be possessed of such a screen. Many have been 
introduced at my suggestion, and have worked most successfully. 
The proper working of a screen depends largely upon the man in 
charge of it. Occasionally, one meets with an individual whose 
mind is made up before he sees it or begins to attend to it, and 
in such hands it has usually a poor chance. I have seen one that 
would not work at all under the care of one man do its work 
admirably when in charge of his successor. 
There are several different forms of screen which we will 
consider by and by. Before doing this, however, let us turn our 
thoughts to the material of which they are to be made. I have at 
present close upon a hundred screens working about my ponds, 
and I have always used perforated zinc, and have found it to work 
well. It is fitted on to wooden frames, and these being all of the 
same size, one can be withdrawn, and another of coarser or finer 
perforation be readily put in its place. This on a fish farm is very 
necessary, as large fish may be taken from a pond and replaced by 
small ones needing a finer screen. Perforated zinc works well, is 
not expensive, and is easily manipulated by any one who can use 
a hammer and nails. Should a hole get punched in it by accident, 
it is easily repaired by lacing another piece over the hole with the 
help of a little brass or copper wire. Ordinary zinc requires 
renewing about once a year, and this is its only drawback, but to 
set against it is the advantage it possesses in being so easily put 
on. It can be obtained of considerable thickness, however, and 
