104 American Fisheries Society 



may thus project before it will be moved downward by the 

 current. Now raise the thin end a trifle and see how quickly 

 the current will have the mastery. 



The suggestions for a fishway, which it is desired to base 

 on these observations, are: 1. The bottom of the fishway 

 should be uninterrupted. A swift current is no great ob- 

 stacle, if only the fish have access at all times to the bottom. 

 Nor is a smooth slippery bottom objectionable but rather 

 the reverse. No argument against this view can be based 

 on the fact that the bottom of most streams is irregular, 

 for in the roughest streams everything is covered with 

 slimy, slippery growths. 



2. There should be a continuous smooth flow along the 

 bottom. To secure this it is proposed to build a straight 

 steep sluice and insert partitions in this sluice leaving open- 

 ings under each partition all the same height and across the 

 entire width of the fishway. It is evident that the total 

 fall will be divided into as many steps as there are partitions 

 and the fluctuations of level above or below the dam will also 

 be so divided and the flow will never be too small nor too 

 great, provided the right number of partitions has been 

 inserted. 



This mode of reducing the head and thereby the velocity 

 of the current is that of the Hockin fishway figured by Mr. 

 Von Bayer (Bulletin of the Bureau of Fisheries, Vol. 28, 

 1908) and at certain stages of water might be that of the 

 Cail and Von Bayer fishways also. The plan proposed dif- 

 fers radically from all of these, however, in three points : 



1. In having the bottom a continuous slope without steps. 



2. In having the openings at the bottom and under the 

 partitions rather than through them, and: 3. In the exten- 

 sion of the openings across the whole width of the fishway, 

 thus avoiding horizontal eddies. It is not claimed that there 

 will be no eddying but it is believed that the eddies will be 

 vertical and mostly above the bottom and that there will be 

 a current along the bottom constantly in one direction, 

 although doubtless varying in velocity at different points, 



