C.— PROTECTION. 



III. — Legislation. 



4. Fishery laws. (See Eeports.) 



IV. — Assistance to fish in reaching spawning-grounds. 



5. Fish-ways. 



pool fish-ways. 



(Ascent made by alternate rapid currents and pools, the latter 

 serving as resting-places for the fish). 



a. POOLS FORMED BY NATURAL IRREGULARITIES OF THE CHANNEL. 



DUNCANNON FISH-WAY. 



Model of fish-way built at Duncannon, Pa., in which the velocity 

 of the current is retarded by means of rocks and bowlders so 

 arrauged as to form a series of pools at different points in the 

 sluice. Designed by J. T. Eothe, Duncannon, Pa. 25,701. 



b. POOLS CONSISTING OF A SERIES OF PONDS OR COMPARTMENTS. 



Shaw's spiral fish-way. 



In this fish-way the water passes by a series of vertical falls 

 through openings in the several rectangular compartments on 

 its way to the lower level. The width of the opening is about 

 one-fourth of the longer side of the box. The extent of the 

 fall varies with the number of compartments and the height of 

 the dam. The compartments are arranged spirally. A gate at 

 the top (not shown in the model) regulates the quanity of water 

 used. Each compartment is provided with an opening at the 

 bottom to admit of drainage in winter. Designed by B. F. 

 Shaw, of Anamosa, Iowa. 39,497. 



C. POOLS FORMED BY PARTITIONS PLACED AT AN ANGLE WITH THE SIDE OF 



THE SLUICE. 



Swazey's oblique fish-way. 



Old style. In this fish-way the partitions extend alternately from 

 either side, sloping upward at an angle of 45° to a point 

 slightly beyond the center of the sluice to form pockets or 

 pools, which serve as resting-places for the fish. In passing 

 through the way the water is caught in the angle formed by 

 L47] 1201 



2444— Bull. 27 76 



