ABTIFICIAL. PROPAGATIOIT OF WHITEFISH, ETC. 11 



At the proper distance apart along the sides of the troughs are 

 holes for the wooden faucets; for ease in manipulating the jars these 

 holes should be 7^ inches on centers and 3 inches above the inside 

 bottom of the trough. The best faucets are the Crandell with the 

 tin key. The faucet is connected with the tin tube by a piece of white 

 or red rubber tube 8 or 10 inches long and | inch in diameter. The 

 tin tube is | of an inch in diameter and 20 inches long; three short 

 legs are soldered to the lower end to hold the tube above the bottom 

 of the glass jar. 



The troughs are placed one above another at a proper distance to 

 accommodate the type of jar used. They are held together by a 

 support made of 4 by 4 timbers, so placed that a row of 6 jars is 

 installed between each set of stanchions. At the Put in Bay 

 hatchery there are 6 rows of jars, making 36 jars between each set 

 of stanchions. This type uses the stagger system in placing the 

 jars on the battery, by which method each jar of the top row sup- 

 plies the next jar immediately underneath. The troughs are held 

 together in the stanchions by the use of ^-inch bolts, with nuts 

 and washers at each end, which also act as a support to the trough. 

 Beginning at the top trough the water supply enters one end, sup- 

 plying each jar on the top row, which in turn discharges into the 

 next trough below. The surplus water passes through the tin over- 

 flow at the opposite end and into trough No. 2, which projects from 

 8 to 10 inches on one end beyond the top trough. This alternate 

 system is continued until the water . is finally conducted into the 

 receiving tank located at the end of the battery. This tank is 24 

 inches deep, 3 feet wide, and of sufficient length to receive the water 

 supply from two batteries. Provision is made at one end of the tank 

 for a screen and an overflow for the diversion of part of the water. 

 The water remaining passes into a series of fry tanks arranged at 

 right angles to the receiving tank, connection between them and 

 the fry tanks being made by means of a 2-inch pipe set 1 foot below 

 the surface of the water and provided with a stopcock. At the Put 

 in Bay hatchery four fry tanks, set in series of two, receive their 

 •water supply from the retaining tank. Each fry tank is provided 

 with a screen near its lower end and a similar connection is made 

 between the fry tank and the receiving tank. The fry tanks are 24 

 inches high, 3 feet wide, and usually 16 feet long. 



These screens are made of brass wire cloth, 60 meshes per inch, 

 tacked to a heavy frame. The screen is pulled very tight before it 

 is fastened so as to present a smooth surface to the air jets. The 

 screens should never be painted. The screen frames are held in 

 place by bolts that pass through the frames and into the projecting 

 cleats in the trough. They are not put in place until the fry com- 

 mence to hatch. If the air pipes are large and are run fairly 

 straight to the screens, an air pressure of from 5 to 8 pounds will 

 be sufficient to keep the screen free from eggshells. 



At the Cape Vincent (N. Y.) station a modification of the battery 

 described in the foregoing pages has given excellent satisfaction. ( See 

 fig. 31.) It carries six tiers of jars, and where vertical space is 

 available it may be made to accommodate a larger number of jars in 

 proportion to the floor space occupied. The troughs in this battery are 

 made of If -inch cypress. Thej^ are 124 inches wide, 9f inches deep on 

 the feed half, and 6 inches deep on the catch end. The shelves, 



