[45] POND CULTURE. 511 



will always be found advantageous to have smaller or larger weirs ac- 

 cording to the size of the pond and the quantity of water" which flows 

 into it, as they are, after all, the best means of regulating the supply of 

 water. It will, under all circumstances, be advisable to keep the sluice- 

 gate under lock and key, so that it cannot be opened by mischievous 

 persons. This can be done in a very simple manner by a lever which 

 holds the boards in position, and which is locked to one of the side- 

 posts. 



In large ponds it may become necessary to construct canals through 

 the banks and dikes for the supply and exit of the water, generally 

 in very steep places. Such canals should be very carefully constructed, 

 so that no damage may be done to the bank or dike, aud experts 

 should be engaged for the purpose. Such canals may also be needed 

 in ponds which have weirs, so as to supply still more outlets for the 

 water, to decrease the force of the stream passing through a pond, or 

 to carry off the Avater from remote portions of the pond, for which pur- 

 poses weirs will not always suffice. For draining the pond for the pur- 

 pose of fishing, there are conduits or pipes underneath the dam, through 

 which the water may flow out. Tbey fully answer this purpose, for 

 weirs or sluices are not so practical in this case, as their management 

 is always connected with some difficulty. 



h and c. The supply of water from springs and, in sky ponds, from 

 the atmosphere, will never be so large as to make it a matter of indiffer- 

 ence whether this supply is constant, or whether there is, in sky ponds, 

 anything to prevent the free entrance of rain or snow water ; but as a 

 general rule these means of supplying water need no special regula- 

 tion. Weirs are therefore not needed, and all that is necessary will be 

 to put a grate at the place where the water enters freely, but which 

 prevents the fish from escaping. Any superfluous water may be car- 

 ried off through outside ditches or be led to the lower pond or ponds. 

 d. A lower pond (or ponds) is filled from a higher pond by simply let- 

 ting the water flow to its destination through pipes, until the desired 

 height of water has been obtained, when the tap is driven in again. 

 I The supply of water coming in during the course of the year rea^^ches 

 j the lower ponds through the outside ditches of the upper ponds, until a 

 ] full supply is obtained, and the superfluous water is carried off through 

 other outside ditches. All that is needed to regulate the water flowing 

 through these various ditches will be to put grates in them at suitable 



1 places. 

 B . — Watek-pipes . 

 To drain a pond for the purpose of fishing two means may be employed, 

 !' viz., taps and stand-pipes. For both these methods pipes are needed! 

 I] These pipes are laid horizontally through the dike. They should lie 

 j 15 to 20 centimeters deeper than the bottom of the pond, or rather of 

 ;j the fish-pit, in which they open, so that they can receive all the water. 

 To prevent the water from flowing out too near the dike, whereby it 



