68 



How to obtain it. 



any account have it too small. It will do no harm by being 

 made too big, and will give less trouble. Where the size can be 

 given in width and depth the matter is simple, but sometimes this 

 is not convenient. There may be an opening through which the 

 water passes that cannot be easily altered, and which at the same 

 time is too narrow for a screen to work. In such a case the 

 screen must project into the pond, and may be on the rectangular 

 system that is, consisting of two sides and a front or it may be 

 made semi-circular, and in this case may be much wider than the 

 outlet. In cases where there is much floating matter and heavy 

 flooding, it may be commenced several yards from the outlet, 

 beginning on the pond bank, and running out in semi-circular 

 form until it reaches the bank again, a few yards on the other side 

 of the outlet. It will be apparent that the greater the dimensions 

 of the screen the less will be the liability to become choked, and, 

 consequently, the more easily will it be kept in working order. 



It is very desirable that a screen should be well fixed, that 

 is, that it should be so let into the banks of the pond that there 

 is no chance of the water flowing round it, or under it, instead of 

 through it. This end can be attained by means of masonry or 

 concrete, in which the screen may work, and which must be well 

 puddled behind. A very simple and effective way of fixing a 

 screen, when made of wood and perforated or woven metal, and 

 one which I have frequently followed, is explained by the 

 annexed diagram : 



Fig. 2. 



