604 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Step : 



1. Box or "pool" fish- ways: 



(«) Overflowing, (old style.) 



(h) With passage-way cut down to floor, (Smith's.) 



(c) With passage-way submerged, (Gail's.) 



2. With contracting galleries, (Pike's.) 



3. With transverse sloping floors, (Steck's.) 

 Inclined plane, without steps : 



1. Plain, (Pennsylvania.) 



2. With partitions at right angles : 



{a) Common style, ("rectangular compartment.") 

 {h) Brackett's. 

 3. With oblique partitions: 

 (fl) Foster's. 

 h) Swazey's. 

 With reference to general arrangement they may be again classified 

 thus: 



1. Extended. 



2. Eeversed. 



These two forms have been applied to most of the step and inclined- 

 plane fish-ways, and can be adopted with any of them. ' 



3. Spiral, (Gail's ; Pike's, &c,.) 



This form is an essential feature of Pike's, and may be combined with 

 the details of most of the step and inclined-plane fish-ways. 



1. — GAP. 



The simplest form of fish-way is a gap in the dam. This appears to 

 have been much in use in British rivers, where it receives the name of 

 "Queen's gap." In low dams, it answers well for salmon. In America, 

 it has occasionally been resorted to for alewives ; and in dams built ot 

 l^lank, it can be made by the simple removal of one or two perpendicuUir 

 planks, forming an opening quite to the bottom of the stream, and, if 

 circumstances be favorable and the height be not great, it works well 

 and saves the expense of a permanent structure. The only instance of 

 a permanent gap-fish-way that I have seen is at Milltown, on the Saint 

 Groix, where Aving-dams are built from either shore obliquely up the 

 stream, and separated at their upper ends by a space several feet wide. 

 Where circumstances permit a dam to be built in this way, it forms the 

 best fish-way that could be devised. 



4. — TRENCH, OR CAPE COD FISH- WAY. 



When a dam is too high to admit of the use of the gap, a more elabo- 

 rate contrivance is necessary. The rudest, and in some cases the easiest 

 to build, is what may be styled the trench-ftsh-way, in which a sufiicient 

 stream of water is conducted arouud the dam over the grouud, in a 



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