mid-water or even near
the surface. As I have said before however, an outlet should be made at
the level lowest part of the bottom, so as to facilitate the emptying of
the pond. The pond should however be made shallower at the lower end.
Fig. 2 shows a section of the upper end, and Fig. 3 of the lower end of
such a pond.

[Illustration: Fig. 1.]

[Illustration: Fig. 2.]

[Illustration: Fig. 3.]

The open trough between ponds in a series should be at least three yards
in length, but it is better if not straight. Stones and gravel should be
put in these troughs in order to make the water as rough as possible,
and if some fresh-water shrimps can be introduced so much the better.

If the water is taken from a stream, a leaf screen must be placed at
some distance in front of the inlet. This may be made of a hurdle
fastened to strong stakes sunk into the bed of the stream. The opening
of the inlet should be at least double the size of the sectional area of
the pipe through which the water is carried to the ponds, and should be
some distance, a couple of feet if possible, below the surface of the
water. It is a good thing to put a wire cage over the inlet, and under
this a perforated zinc screen is necessary. The inlet from the stream
should be so placed that it is easy to get at and clean. The best form
of covering for the inlet into the pond I have seen, is a zinc cylinder,
the base of which fits over the end of the inlet pipe. The part of this
cylinder, which projects 18 inches beyond the pipe, is perforated, as is
also the flat end. This can easily be taken off and cleaned, and breaks
up the water, making it fall into the pond like a shower bath, causing
considerable aeration.

The inlet from the stream should have a trap with which the water may be
shut off, as also should the outlet from the pond. When the cylinder on
the inlet into the pond is taken off for a minute or so to be cleaned
out, both these traps must be closed. This lessens the chance of any
creatures likely to do harm getting in during the cleaning. The
perforated zinc screen at the inlet from the stream will probably stop
any such creatures, but too great care cannot be exercised, and it is
always best to be on the safe side.

Movable covers of netting over the ponds are most certainly advisable,
particularly if the rearing ponds are in an unfrequented spot near a
stream. On one occasion I caught four kingfishers during a period of
three weeks, a