REPORT OF COMMISSIONERS OF INLAND FISHERIES. 79 



One chief object which has been kept constantly in mind in the 

 construction of this apparatus is the possibility of its use at any 

 station where the water is comparatively quiet, and also the pos- 

 sibility of extending- indefinitely the capacity of the apparatus 

 without the expense of a large amount of additional machinery. 

 The floats, such as were attached to either side of the house-boat, 

 can be attached to one another, and the power transmitted from 

 one float to another by the coupling shafts, such as were used be- 

 tween the. house-boat and the float ; and it is probable that the 2^ 

 H. P. engine which we have used is capable of running three or 

 four times as many paddles. 



The accompanying photograph and drawing will illustrate, 

 without much further description, the essential features of the 

 construction and proportions of the apparatus, but there are a 

 few features to which we may refer especially : The canvas bags 

 seem to become foul much less quickly than those made of scrim, 

 and the small windows in the former provided a sufficient area for 

 the incoming and outgoing currents of water. The current created 

 by the moving paddles tended to draw in the bottom of the bags, 

 brtt this tendency was easily counteracted by laying strips of fur- 

 ring across the bottom framework. The bulging out at the sides, 

 from the same cause, was a distinct advantage. An experiment 

 was tried with a bag of the small size (6x6 feet square) made of 

 tarred bobbinet. This bag, whether from the fact that it was 

 tarred, or that its meshes were larger than those of the scrim bags, 

 became less foul than the others ; but since it was fragile and ex- 

 pensive to construct, only one of these was put into use. 



