86 
THE CALIFOENIAN SALMON. 
netting to keep off shags and cormorants. The water of 
the brook being muddy, I had a very elaborate filtering 
arrangement erected, which, however, was of little service, 
as it filtered but a small quantity of water, and I found it 
better, as the hatching was going on rapidly, to dispense 
with filtering and make use of a larger stream. The 
hatching-boxes are at different levels, beginning at four 
feet above the ground, and going down to two feet, a fall 
being required from one to the other. Each box is set 
perfectly level, and the current is regulated by the depth 
of gravel. • 
Many experiments as to the best mode of fish-hatching 
have been tried, and a very efficient apparatus has been 
invented by M. Coste, the great Erench Pisciculturist, 
consisting of a zinc or iron japanned trough, having 
movable frames fitted with glass rods, between which 
the ova lie suspended, allowing any sediment or particles 
of hatched eggs to fall through, and which may be cleaned 
out without disturbing the eggs. This hatching-box 
obviates the difficulty that has been experienced, of a 
fungoid growth which is apt to form on wooden hatching- 
boxes, but it is more suited for an amateur to hatch out a 
few ova, than for hatching large numbers. 
An American discovery, of the advantages to be obtained 
by the use of charred wood for hatching-boxes, has solved 
the problem most satisfactorily, it having been found that 
no fungus appeared on the carbonaceous surface, after a 
long and severe test. In one of the hatching-boxes, by 
way of experiment, I placed a bottom of ribbed glass, 
but found, after trying this and also a charcoal bed, 
that nothing suited so well as fine gravel, of a dark 
colour. If the gravel be of a light colour, the dead eggs 
are less easily seen, from their colour being also white. 
It is better that the hatching-boxes should be three to 
