62 FISH—-CULTURAL ASSOCIATION. 
duction the breeding area of water from which they had been 
excluded, promised the means of restoring these most valuable 
fisheries. 
The gentlemen who were then Commissioners of Fisheries for 
the State of Virginia, were pleased to select me to visit the Cen- 
tennial Exposition, at Philadelphia, with instructions to make 
a careful study of the models of all the forms of fish-ways there 
exhibited, with the view of finding one that would be adapted to 
our purpose. A careful study of all was made, and I was req 
luctantly forced to the conclusion that none of them fulfilled 
the necessary conditions of successful operation, and I returned 
discouraged, with the conviction that an efficient shad-way was 
a thing of the future. 
The conditions to be satisfied in a successful fish-way con- 
struction are as follows: 
First—The water should be delivered down a straight unob- 
structed channel. 
Second—In sufficient volume to invite the entrance of fish. 
Third—With such moderate velocity as to permit their ready 
ascent,’ 
Fourth—With a view to economy in construction, it is im- 
portant that the inclination or slope of the way, should be much 
more considerable than in the ordinary inclined plane fish-way. 
How to construct so as to fulfill these conditions was the 
problem to be solved. Two methods suggested themselves. It 
was possible to make the water do work in its descent and thus 
control velocity. A fish-way could be constructed on this prin- 
ciple by an evident modification of the ordinary turbine wheel, 
and such a fish-way could be made to serve both as a passage-way 
for fish and as a motive power for machinery. This idea, how- 
ever, was soon abadoned for the double reason of its complexity, 
and the limitation of its application that would necessarily exist. 
The second fruitful idea*was that if each molecule of water 
could be compelled to traverse a constrained path, its final direc- 
tion in any one circuit being against gravity, it could be brought 
to rest at a lower level—the friction developed in movement 
having neutralized in part the force of acceleration. 
The molecule falling from its second position of rest through 
