THE NEW ART OF BREEDING FISH. 153 



the river, and the ponds should be fed by a small 

 Btream, or ' lead ' taken from the river, so that the 

 temperature and all the conditiofts of the one may, 

 in every respect, agree witii those of the other. At 

 the spot you take the 'lead' off the river, you com- 

 mence the erection of a wall to shut out the main 

 current. The wall may be built in the river by the 

 side of one of its banks, and its height then is to be 

 greater than the highest flood-marks of the river. 

 In the bottom of the wall, where it takes the 'lead' 

 off the river, an opening or drain-mouth is to be 

 constructed of the width of the current you wish to 

 flow through your ponds inside the defending wall. 

 This opening at the upper end of the wall is to be 

 so framed, that whether the state of the river is low 

 or high, the supply of water to the pond will be nei- 

 ther injuriously diminished nor increased. The 

 drain-mouth, or opening in the wall, is to be secured 

 by a strong iron grating, the bars of which are to be 

 half an inch apart. This grating will prevent the 

 accumulation in the ponds of any thing hurtful to 

 them. The bed of the ponds must be dug up to 

 the depth of about five feet, and they must be nine 

 feet in width, and eighteen, in length. Their bot- 

 tom must be lower by five feet than that of their 

 feeder. The bottom, however, must not be quite 

 flat, but graduated, rising from the end furthest 

 from the head of the current towards the opening 

 or drain-mouth. The necessary inclination can be 

 given to the bottom of the pond by beginning with 

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