174 American Fisheries Society 



accumulations of ice, as it is dismantled during winter and operates 

 only when the fish run in the spring, summer, and fall. (3) It 

 is automatic and operated by a counterpoise supplied from an 

 elevated tank which fills by gravitation or by hydraulic ram. It 

 may also be operated by electrical or other power. (4) It is adapted 

 to all heights, 10 feet to 100 feet or more. (5) It is capable of being 

 placed in any position in front, or at the side, or some distance 

 below, the obstruction. A longer or shorter horizontal sluiceway 

 enables the fish to pass from the top of the elevator to the pools 

 of water above the dam or falls. No mill or power house is 

 deprived of any water-power. (6) By adjusting the valves, the 

 ascending and descending movements of the fish-trap or fish cage 

 can be arranged at any interval, 15 or 30 minutes, or many hours; 

 thus allowing ample time for a sufficient number of fish to enter 

 the cage. (7) Should more enter the cage than the counterpoise 

 can raise there will be no movement until some of the fish swim 

 out, but the counterpoise is sufficiently heavy to raise the quantity 

 of fish likely to enter during the short intervals allowed. (8) The 

 cost of this device is much smaller than most other fishways in 

 existence. It can be built for a few hundred dollars, being little 

 more than a frame work, lightly but strongly made; whereas, some 

 of the best fishways are costly structures of cement, masonry and 

 timber, and cost many thousands of dollars. 



