92 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



struction, the shaft beams should be high enough to escape the box 

 when the latter is raised out of the water (fig. 5). 



The boxes are buoyant and have to be forced down into position, 

 where they are held fast by two planks across the top at the end of the 

 box (figs. 4 and 11). The .planks are mortised into the corner posts 

 before referred to, so as to prevent lateral movement, and are fastened 

 down to the beams of the float by heavy adjustable cleats secured by 

 bolts (fig. 10). 



The boxes are painted inside and out. 



When a box is to be raised, the cleats are loosened, the planks re- 

 moved, and ropes from the drums of a transportable windlass are 

 hooked into the ring-bolts of the bottom corners (figs. 4 and 12). The 

 doors are then opened and the hand windlass put into operation. One 

 man alone, has raised a box in fifteen minutes, and two men in five 

 minutes. These boxes, the windlasses, and many other things, were 

 designed and constructed by the superintendent, Mr. E. W. Barnes. 



Propellers. — The size and shape of propeller blades found to be 

 most satisfactory vary according to the requirements of different fry. 

 The form of those most used for lobster fry is shown in fig. 6. 

 They consist of two wooden blades, each 4 feet 2 inches long, 

 and 8 inches wide at the base, tapered to 5 inches at the apex, and 

 painted all over. Along the middle line the thickness is about 1^ 

 inches, but from this to either edge is a long bevel which leaves about 

 one-half inch at the edge (fig. 18). Each blade is fastened with iron 

 straps to a piece of galvanized gas pipe, which is screwed into a four- 

 way cross coupling (fig. 18). The latter admits also the vertical gas- 

 pipe shaft running upward toward the gears and a short vertical steel 

 shaft below which sets into a socket consisting of a short piece of 

 large gas pipe fastened to the bottom of the car by a flange. This 

 serves as a lower bearing or guard to the propeller shaft (fig. 18). 



The upper part of the propeller shaft is continued by means of 

 couplings through the longitudinal shaft beam and carries a mitered 

 gear at the top (fig. 14). In order easily to disconnect and take out 

 the propeller a heavy iron sleeve coupling is inserted into the pro- 



