4:i 



to tlie huudred ibliowing the lowest part of tlic chaiMiel, would 

 require a rock cutting fifteen liundred feet long, v/ith adG]»tli 

 "f twenty feet in the middle; wliicli would be greatly increased 

 by any lateral deviation in consequence of tlie higher ledges 

 on each side. Besides tlio whole of the Masting and renioval 

 of the rock would have to bo carried on in the face of the tor- 

 rent, unless the dam of the Water V/orks should be extended 

 to the Virginia shore, and all the water bo allowed to escape 

 b}' way of Little Eivcr. 



From what I Isave read in tlie report of the United States 

 Fish Commission, which you were kind enough to send nie, 

 I am inclined to believe, that if a considerable volume of 

 water were made to issue obliquely into the main cliannel, at 

 a point lower down the river, and a.t a velocity, although not 

 great enough to prevent the ascent of ghad, yet, much exceed- 

 ing that of the larger quantity in the main channel: that most 

 of the fish Avould be attracted by the superior current, and be 

 induced to follow the artificial Avater-way, and if a barrier were 

 throv/n across t.-e main channel, just above tlie confluence, 

 tiien all of them v/ould take that course. 



I think that such, a fisli-way can be constructed at a very 

 moderate expense, by following the route of Little River and, 

 v\-hat la apparently, a continuation of the same cleft in the 

 ledge belov/ the great transverse cleft. 



I have estimated the cojist of such a way, supposing a grade 

 descending at the rate of four in on? hundred to be adopted. 

 Although such a descent would produce a velocity far too 

 rapid if the channel h.ad straight and smooth sides, and bot- 

 iora with much deptli of fiov/; yet, if the water had to strug- 

 gle through and over ragged })rojections of rock, or fragments 

 too heavy to be moved, it would be so impeded that it would 

 not obtain a general velocity that could not be easily overcome 

 b_y the fish ; vrhile every v.diere they v/ould find either a resting 

 place or a solid point against which to react in their endeav- 

 ors to stem or mount the current. I have frequently obsei-ved 

 Ml long stretches of mountain streams descending nearly uni- 

 formly at, at least, as gj'cat an iiicliuation as tliis, tliat the 

 S!)eckled Trout Isad iio difiiculty in mounting, and that I 

 '■ould easily keep U;) with iloating ])!;r<.!cles, witliont oxccpd- 

 ing .'i trot on a pathless ground. 



