42 Modern Fishcnlture in Fresh and Salt Water. 



from all sides except when the sun may shine directly 

 on the troughs or eggs. If this is not practicable then 

 make covers for the troughs ; these may be hinged so as 

 to lie over on the adjoining trough. 



Good, clear white pine is the best material for 

 troughs, if free from sap and knots. It swells tight and 

 the nails can be set up, if needed. I have used yellow 

 pine, but it is hard and imyielding and is more difficult 

 to make tight because it does not swell, yet it is more 

 lasting than white pine. A trough of the latter is good 

 for from four to eight years, and then soft spots of sap, 

 or heart, begin to show ; a patch or two of one-half inch 

 pine is let in, embedded in coal tar, and it goes for a year 

 or two more. Troughs of yellow pine made in 1886 are 

 good as ever twelve years later, yet they are unhandy to 

 tack screen strips in and more so to pull a brad from. 

 Where these woods cannot be obtained some native 

 wood must be substituted. White cedar would be an 

 ideal wood, if it grew large enough. 



A distributing trough running across the head of a 

 series of hatching troughs has been the regulation mode 

 of supply in hatcheries since they have existed, and the 

 practical worker knows what a nuisance they are. Run- 

 ning the length of the building, the least settling opens 

 the joints, and their length forbids their being moved 

 after having been built in position. Then a bit of sap- 

 wood or heart in some spot will decay, and the whole 

 trough will be condemned and a new one made. The 

 life of such a trough may be from four to ten years, but 

 it is always under suspicion of leaking at any time. I 

 had one 60 feet long that lasted eight years, but was 

 calked and pitched many times, and I thought of lining 

 it with sheet lead of about three pounds per square foot 

 and then replace the wood piece by piece, as needed. 



