140 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



along the well of the houseboat, connection is made, by mfeans of 

 mitred gears, to the vertical paddle shafts. (Plate XVIII.) In 

 these the speed is reduced by the gears to ten revolutions. Each 

 paddle can be thrown out of gear independently by means of a lever. 

 This enables each bag to be manipulated separately without shutting 

 off the entire machinery. 



4. Construction and Care of the Rearing Bags. 



The canvas rearing bags (Plates XVIII and XXI) are 10 feet, 2 

 inches sc^uare, 4 feet deep, and made of 10-ounce duck. In the 

 bottom and on two sides are windows. The frames of these are 

 made of furring on the outside and a strip of lattice on the inside, 

 the two being fastened together with brass screws, thus binding the 

 edges of the canvas to the copper wire netting, 20 mesh to the inch, 

 which forms the windows. A hem is made around the top of the 

 bags, in which a rope is run. This hem is open at each corner, so that 

 at those points loops of the rope can be put over line cleats, on the 

 top of the haul-down posts, to support the corners of the bag. The 

 sides are held up by ropes passed through grummet holes in the 

 centers of the sides. A free edge is left around the outside bottom 

 of the bag, with grummet holes at frequent intervals. Through 

 these holes marlin or some light rope is passed and the bottom 

 stretched quite taut over a square framework of one-half inch gal- 

 vanized gas pipe which, for this purpose, is made a little larger than 

 the bag. But however tight the canvas is drawn the upward current 

 of water will pull up the center of the bag and endanger its being 

 struck by the paddle. This is best remedied by placing two strips 

 of furring, long enough to project over the sides of the framework, 

 on the bottom of the bag underneath the framework. Then thin 

 lattice strips, just the length of the inside bottom, are placed within 

 the bag opposite the pieces of furring, and screwed down to the 

 furring strips. Care of course should be exercised to round the edges 

 of both lattice and furring strips so as to prevent them from cutting 

 holes in the canvas when it is drawn up by the current. 



