946 KEPOKT OF COMMISSIONER OF FISH AND FISHERIES. 



2.— WATER. 



The first thing to be sought is an ample supply of wholesome water, on 

 a site where it can be brought completely under control and the requisite 

 fall secured. In this matter there is quite a range of choice. The very 

 best is the water from a stream fed by a clean lake taken a short distance 

 below the outlet of the lake, with an intervening rapid. Such water is 

 commonly quite even in volume and temperature, and comparatively free 

 from sediment and harmful impregnations. It is cold in winter and warms 

 up slowly in spring, giving assurance of a slow and normal development, 

 which is more conducive to health and vigor than a very rapid development. 

 The passage down a rapid, though by no means an essential point, will 

 further improve this water by charging it highly with air. After this, I 

 would choose the water of a brook that is fed largely by springs, so as to 

 insure constancy in the supply and some moderation of the temperature on 

 warm days; but it is better to have the water flow a long distance in an 

 open channel before using, and, if possible, over a rough and descending 

 bed, that it may be well aerated, and in cold weather somewhat cooled 

 down from the temperature with which it springs from the ground. 

 Thirdly, choose pure spring water ; but in all cases where this is necessary 

 provide a cooling and aerating pond, that you may have the original warmth 

 of the water subdued by the cold of the air before it reaches the hatching 

 troughs, and that it may absorb more or less air by its wide surface. 

 Lastly, choose ordinary river or brook water, as clean as possible. These 

 kinds are considered inferior to spring water by reason of their liability to 

 floods, drought, muddiness and foulness of otlier sorts, and in cold climates 

 to anchor ice. The water of a stream that has its source in a not very 

 distant lake or spring is not considered orcUnary^ river or brook water, 

 but is advanced thereby into the first or second rank. Between these 

 different sorts there is of course an infinite number of gradations. If lake 

 water cannot be obtained, it would be of some advantage to have a supply 

 of both spring water and brook water, depending for ordinary use on the 

 brook water or a mixture of the two, and on the spring water for emergen- 

 cies, such as the freezing, drying, or excessive heating of the brook, floods with 

 accompanying muddiness, etc. Avoid water that comes from boggy and 

 etagnant ponds and marshes ; for though excellent water, capable of bringing 

 out the most vigorous of fish, may sometimes be had in such places, yet 

 when not supplied by springs it is dependent for its freshness and good 

 qualities upon sufficiently copious rains, and if these fail, as they are liable 

 to, the water may become foul and unfit. The best time to select a site 

 for a hatchino; establishment is in time of extreme drouQ-ht. If the site in 

 question has at that time an ample supply of pure, sweet water, the first 

 requisites are fulfilled. But if such an examination discloses any lack in 



