I052 



BULI^ETIN OF THE BUREAU OF FISHERIES. 



Tank. 



Sec/-/o/T JI.-B. 



/'/a/T. 



Fig. 19. — Reckcn. 



Here the water chamber is shown full, and a water tank at the right is filling. When latter is full it will descend of 

 its own weight and raise the gate, to which it is attached by means of a cable over a grooved wheel, allowing lock chamber 

 to empty to lower level. When lock chamber is empty a float and gate in the upper partition, rigidly connected together. 

 will be down; water tank being cut off from supply will also become empty, the water dripping gradually out of the 

 bottom opening as shown. Supply through a notch in upper partition will begin to fill lock chamber and lift float and gate, 

 thus repeating the process described. 



THE IMPROVED CAIL FISHWAY. 



The "Improved Call fishway" (fig. 20) is a combination of the incUned 

 plane system with the pool and fall or step system. It consists of a series of 

 compartments arranged in steps and separated by a number of cross partitions, 

 which are provided with suitable orifices at the bottom, alternating successively 

 from side to side, so as to allow the fish, according to their individual habits, 

 to ascend the fishway by either leaping over the small waterfalls over the cross 

 partitions or by darting through the orifices, at the same time enabUng them 

 to rest in the compartments in comparatively still water. 



The present improved Cail fishwaj^ embodies certain improvements made 

 by B. M. Hoecht, of Germany, who built at Hameln, on the lower Weser, a 

 large fishway on the Cail principle, constructing it of masonr}^- and concrete, 

 with a fall of about i foot in 8 feet. The design was brought to another form 

 by the present author, and is now the pattern recommended by the United 

 States Bureau of Fisheries. Its construction embraces all requirements for a 

 fishway, as enumerated above, viz: 



I . The slope of the fishway as per figure 20 is in a proportion of i vertical 

 to 4 horizontal, the fall from compartment to compartment is i foot 6 inches, 

 and the greatest velocity of the current through the orifices is less than 6 feet 

 per second. 



Note. — V=»»\/29H=o.57 X 8 X 1.23=5.6 feet per second. V is the velocity in feet per second ; 9, 

 acceleration per second of a falling body, 32.16 feet; H, head of water column proper, 1.5 feet; »«, 

 coefficient for contraction obtained by actual experiment, 0.57. 



