88 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



ease of rearing lobsters. In the case of all species of fishes which we 

 have attempted to rear the problem is easier than in the case of 

 lobsters. 



APPARATUS. 



GENERAL DESCRIPTION. 



The apparatus as at present installed has proved capable of rearing 

 the larval and young stages of fishes and of invertebrates belonging to 

 several different groups. The main features are as follows: A house- 

 boat consisting of two decked pontoons, 4 by 4 feet square in section 

 and 50 feet long held 8 feet apart, the intervening space decked and 

 covered by two houses 10 by 10 feet square and 10 by 20 feet, re- 

 spectively, flanked on either side by two floats attached to the house- 

 boat and made of 6 by 6 inch spruce timbers bolted together and 

 buoyed up by barrels. The spaces between the timbers of the floats 

 are divided into areas 12 by 12 feet, to contain the hatching cars, and 

 into alleyways about 2 feet wide, to contain the supporting barrels. 

 (See diagram and figs. 2 and 3.) 



The inclosures for confining the fry are in the form of 10-foot square 

 boxes (fig. 6) having two windows in the bottom and two windows in 

 two sides, the windows screened, in the case of lobster fry and very 

 small fishes, with fine-meshed bronze woven wire. 



In each box or car a pair of propeller blades, adjustable to various 

 angles, are horizontally placed, attached to a vertical shaft with 

 proper bearings (figs. 9, 14, and 20). By the revolution of the pro- 

 peller blades, the water is kept in circular and upward motion (fig. 

 4). The propeller shaft carries at its top a gear, which engages a 

 similar one with half the number of teeth borne on a horizontal lon- 

 gitudinal driving shaft. The paddle shaft can, however, be instantly 

 thrown out of gear by a lever (figs. 21 and 22). The longitudinal shaft 

 transmits the power to all the propellers in one float (figs. 2 and 3, and 

 diagram). It receives its power from a shaft running transversely 

 across the float, the two shafts being connected by mitered gears 



