he amateur. A spring is the best water
supply as a rule, for the water is usually of a fairly even temperature,
and does not require filtering, but water from a stream where trout are
known to live is quite safe. A few years ago it would have been
necessary for any one wishing to take up fish culture, to erect a
building in which to place his hatchery if he intended to hatch any
number of eggs, in order to guard against frosts. At the present time,
the eyed ova of even the brown trout (_Salmo fario_) can be obtained
sufficiently late to be safe against a frost severe enough to cause any
damage, and as the rainbow trout (_Salmo irideus_) spawns in February
and March, the amateur is, at the time he receives the eyed ova, quite
safe from frost.

The best method to pursue is to make long narrow ponds, with a current
running through them, and to hatch the eggs out in trays and boxes
suspended in these ponds. When the young fish hatch out, the trays which
contained the ova can be removed, and the young fish kept in the boxes.
Later on the young fish can be released from the boxes into the ponds. I
shall subsequently describe how these ponds, trays, and boxes should be
made.

The rearing ponds should be made, if possible, at a fall in the level of
the water supply, so that they may be easily emptied. This is an
important point which is frequently overlooked by amateurs. There should
be an outlet on a level with the bottom of the pond, and if the water
escapes through a pipe, that pipe should incline downwards. This, in a
series of ponds, of course necessitates the ponds being at different
levels, but the water is thus under much better control than if the
outlet is at a higher level, and the ponds are easily emptied. Ponds
may, however, be worked successfully with the outlet in mid-water, or
even near the surface, though this does not ensure such a certainty of
change of water throughout the pond. It is not, however, always possible
to obtain such a difference in level between the supply and waste. In
such cases the ponds should be made shallower near the outlet.

A popular idea seems to be that a gravel bottom is necessary for the
well-being of trout; this is quite a mistake. Personally, I believe that
a good earth bottom is best in a rearing pond, and even in a pond lined
with concrete I should always put a layer of mould, preferably turf
mould, at the bottom. With the use of this mould during the subsequent
operations in