yi 
ova. A very much smaller supply will suffice during the 
earlier stages of incubation, but it is absolutely necessary 
to be able at any moment to command a sufficient supply 
in case of emergencies, such as are frequently occasioned 
by frost or by unusually warm weather. 
Next only in importance to the water itself are the con- 
nections between the source and the hatchery. In making 
the connection with the spring it is safest to follow the 
spring a few feet below ground and fill in the hole with 
large stones. Where many small springs require to be 
tapped, a collecting well should be dug, lined with rough 
masonry, into which all the springs can be led; the con- 
nection to the hatchery from this well should be made by 
leading a glazed spigot and faucit pipe to the point nearest 
the hatchery, which will give sufficient pressure to feed the 
whole house by gravitation ; here another small well, also 
lined with masonry, must be constructed, and from it a 
metal pipe (as fireclay will not stand much pressure) led 
into the hatchery, this arrangement keeps all the pipes 
underground, where they are safe. 
The connection with the stream to bring in river water is 
not so simple, the greatest care must be exercised to secure 
a constant supply, and the difficulty of forming a perma- 
nent and perfectly safe connection is always very great. 
Leaves and debris are in some streams very troublesome, 
and ice at the beginning of a frost is a serious source of 
danger, floating against the screen or grating, and freezing 
to it. I once lost 300,000 Lochleven Trout ova from this 
cause. The winter had been unusually severe, the thermo- 
meter for several weeks never rose above 25° Fah., but at 
the beginning of February a thaw set in, and by the Ist of 
March every trace of ice had disappeared. The stream 
which fed the Fishery was in spate, and one of my hatching 
