39 



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 arid 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 1st of 

 March every trace of ice had disappeared. The stream 

 which fed the Fishery was in spate, and one of my hatching 



