How to obtain it. 67 



then lasts much longer. Perforated iron plates do very well, and 

 are of course more permanent. They require no frames, and are 

 quite easily fixed. An ordinary iron grating is also excellent, but 

 it must be borne in mind that a fish can readily pass between two 

 bars of metal which could not possibly pass through a round hole 

 of the same diameter. The bars may be a quarter of an inch or 

 they may be half an inch apart, but the greater the width between 

 them the more readily will fish pass through and escape. It may 

 be argued that fish do not go down stream out of ponds. I ^ 

 know many ponds where there is no outlet screen, and where it 

 has been supposed there is no need for one. This is a mistake, 

 however, and I have met with instances in which fish have been 

 lost in considerable numbers owing to it. At times, and under 

 certain circumstances, they will and do go down stream if not 

 prevented. There are some instances, however, in which a large 

 number of fish may run up stream into a pond, and of course all 

 things have to be taken into account, and each particular case 

 treated according to circumstances. One thing I am quite sure 

 of, and that is, that every fish pond that has been specially made 

 and stocked with fish, and that has a regulated supply of water, 

 ought to have an outlet screen. 



Having decided upon the material that is to be used, the 

 next thing is to consider the more important points that are to be 

 observed in the fixing of a screen. We must first be sure that it | 

 is capable of passing all the water during rainy weather. This is 

 in itself a very simple consideration, and in the case of a well 

 made pond that is not subject to flooding, is easily calculated. 

 By having a screen that will pass double the quantity of water 

 that can by any possibility flow from the pond, it should be fairly 

 safe. Of course, the amount of floating matter that is liable to be 

 driven on to it must be well considered and allowed for, and it is 

 better to have the screen twice as large as is necessary than to 

 have it just a little too small. One double the capacity required ^ 

 is usually large enough for all emergencies. 



There are so many old ponds in use that are liable to have 

 floods tearing through them, that I will just give a hint or two 

 concerning them. The chief point in their case is to have the 

 screen large enough. Make it as big as you like, but do not on 



