38 



eggs to impregnate and sell. The shells of those taken 

 from trout living in limestone waters are found to be 

 thicker and harder than those obtained from soft waters. 

 This may come from the lime in the water, and is an 

 advantage in rendering the eggs more easy to transport 

 with safety, than where the shells are very delicate. 



The supply of water necessary for a given number of 

 trout is yet unsettled. For a series of ponds turning 

 out one thousand large fish yearly, the water supply 

 should fill a four inch pipe. This question will be treated 

 more at length hereafter, but it is always safe to have as 

 much water as possible, for within reasonable limits one 

 can hardly have too much that is to say, if the dams 

 and sluices are solid, and the screens do not clog. It 

 must not be forgotten that abundance of pure water is 

 as essential to fish as abundance of pure air to man. 



In saying that ponds must not have a gravelly bot. 

 torn, we do not mean there should be no gravel. The 

 trout must have access either to the raceway or some 

 other spot of gravel to rub off parasites. This they 

 cannot do if the bottom is wholly of mud and they are 

 excluded from the raceway. 



CHAPTER IV. 

 HATCHING HOUSE. 



As a convenient illustration of a hatching house, we 

 will present a view of the State establishment at Caledo- 

 nia, as it was in the year 1875, the subsequent changes 

 not being material to its efficiency, It is located on the 

 stream where Mr. Seth Green had his original trout 

 hatchery, and which is probably the finest site for the pur- 

 pose in the United States. The source of Caledonia brook 



