How to obtain it. 



109 



getting up into the ponds. Keep the bottom of each pond 

 nearly level for two-thirds of the length, and let the tail end slope 

 upwards to the level of the raceway (one foot deep.) This slope 

 may be covered with gravel. About the centre of each pond 

 place a four-inch pipe or tile lengthways on the bottom. I use 

 four-inch sanitary pipes. If these be selected, place the pipe with 

 the flange up-stream, and over it build an embankment of sods up 



Fig- 3. 



to the water level, leaving a gap in the middle. Take care to 

 make it tight, so that the water can only pass it by flowing either 

 through the pipe or over the gap in the sod bank. The sides of 

 the ponds may be perpendicular, or bevelled, as may be most 

 convenient. Where the nature of the soil will admit of it, make 

 them nearly perpendicular ; should it be necessary to build them, 

 do it to a large ex ent at least with sods. 



