59 



that other materials do, and, as one manufacturer said : " We 

 do not use as much chloride of lime in a month as we did in 

 a day before we began using wood-pulp, and you will find that 

 this is the rule with all the paper mills." In conversation with 

 other paper manufacturers they confirmed this statement, and 

 therefore there is less than four per cent, of poison from the 

 paper mills than there was before wood-pulp was used to 

 make paper. 



DAMS AND OBSTRUCTIONS. 



The first obstruction that a salmon meets in the Hudson is 

 the State dam at Troy, which barred their ascent until in June 

 last when a rise in the river gave two feet of water on the crest 

 of the dam, and some salmon went over it. These are the 

 fish referred to above, seen at Mechanicville. The State 

 Legislature made an appropriation for a fishway in this 

 dam, and one was built last summer, after the salmon run 

 was over, by the McDonald Fishway Company, After the 

 completion of this fishway I was in Troy, but the water was 

 too high to see the structure, which I am informed is sub- 

 stantially built and is complete in all respects. This form of 

 fishway differs in principle from all others, and from a study 

 of fishways in Europe and America I believe it to be the best 

 in use. I have drawings of all different fish passes in the 

 world, some of which have never been published, and some 

 of them are very odd. When in charge of the department of 

 American Fish culture at the International Fisheries Exhibi- 

 tion, held at Berlin in 1880, I gathered a mass of material 

 which was never published, because the Government did not 

 issue a report of that exhibition, and among my sketches are 

 some odd fishways in the English department. Allowing me 

 to judge, I will say they were, some of them, of a most prim- 

 itive sort, and of little use to most fishes. I merely cite this 

 to show that I have paid attention to the construction of fish- 

 ways and have a knowledge of the principles of all the differ- 

 ent fishways, without professing to know anything about the 



