58 



day; but this might be done by watchmen at the mills, or an 

 inclosure might be made in the tail-races of the mills where 

 it would be difficult of access. I believe that some eggs might 

 be taken next season, but experiment only would determine 

 the number and cost of obtaining them. If the operations 

 were confined to the upper river a few might be obtained at 

 Hudson, through Matthew Kennedy, and taken up in a fish 

 car, to add to the Troy catch. If the lower river was to be 

 worked for fish to store at Cold Spring Harbor, a small sail- 

 boat, with a well in it, would be needed. 



POLLUTIONS OF THE RIVER. 



In my opinion, ordinary house, or water-closet, sewage does 

 no harm to fish in a river. In proof of this, I would call at- 

 tention to the fact that shad have increased in the Hudson, 

 through artificial culture, in spite of the growth of cities along 

 its banks. Chemical works pollute the water to some extent, 

 but the injury depends entirely on the relative amounts of 

 chemicals and water. A poisonous stream entering one side 

 of a river does not mix at once with the whole stream, but 

 continues down one shore, and is finally precipitated, and be- 

 comes harmless. The poisoned water would kill a fish enter- 

 ing it, but the instinct of the fish teaches it to avoid it. At 

 times the muddy water of the Missouri river can be seen for 

 many miles below its junction with the Mississippi, and this 

 will serve to illustrate this point. 



The paper mills formerly poured great quantities of chlor- 

 ide of lime in the river, and this substance was claimed, 

 rightly or otherwise, to be the cause of the decrease of shad 

 in the Connecticut river, some years ago, because of the 

 paper mills at South Hadley Falls, Mass. There are paper 

 mills on the Hudson from Troy up to Jessup's Landing, both 

 numerous and large, but in all of them that I visited I was 

 told that the use of chloride of lime had decreased to a mere 

 fraction of what was formerly used. In these mills wood-pulp 

 is the basis of paper, and it does not require the bleaching 



