How to obtain tt. 125 
Suitable water is such an important factor in the successful 
working of a hatchery, that too much caution can hardly be used 
in the selection of the site for the building. Some very clear and 
good-looking waters are not good, and it really becomes the work 
of an expert to decide what is suitable and what is not. I have 
seen excellent work done in a hatchery where only river water has 
been used, and I have seen spring water that to look at appeared 
perfection itself, yet did not do its work at all satisfactorily. Some 
spring waters contain too much iron, lime, or other deleterious 
ingredient, and hence the great care that is required in the 
selection of a suitable supply. : 
Therefore, where the incubation and hatching of ova is to be 
carried on on an extensive scale, it is better to consult an expert. 
Where limited operations only are intended, test the water 
by keeping some trout in it, and, if possible, hatch a few ova, and 
rear the fry for a season by way of experiment. 
Have the water analysed. 
Having selected a suitable spring, the next consideration is 
the construction of a hatchery. J have seen several sets of 
hatching apparatus worked out in the open air. The objections 
are that such hatcheries are exposed to the action of frost, which 
in very severe weather is likely to cause damage, and they are 
liable to be tampered with by man or beast, which should not be 
the case. I once had a spring which threw a copious supply of 
excellent water, never below 38° Fahrenheit. Such water would 
answer well for an outdoor apparatus, as it could easily be made 
to pass through a series of hatching boxes before being reduced to 
the freezing point. But most water would be likely to give 
trouble at times. Therefore, if it be practicable, place the 
hatching apparatus inside a frostproof building. In our climate 
an ordinary stone and lime wall is sufficiently frostproof for the 
purpose ; an ordinary slated roof is not. Thatch will do, but it 
has the objection that it needs constant repair and harbours 
vermin. Underground hatcheries, when the situation will permit 
their construction, are excellent. But an ordinary stone-built and 
slated building will be found in practice to answer all requirements 
if felt be laid under the slates. The temperature inside it may be 
kept at any desired point by means of hot water pipes, which 
