784 REPOET OF COMMISSIONER OF FISH AND FISHERIES. [2] 



for the fish. I took the wire cloth fr®m bottom of cone. It made a 

 slight change in the air-bubbles, they were in finer particles. 



June 14. — The fish appeared in a healthy condition. At 12 m. I arranged 

 one of the cylinder cans with an aerator attachment for conducting air 

 and water to the bottom of the can. The water and air passed down 

 through the pipe, and the overflow was through fine perforated tin at 

 the top of the can into the overflow chamber, where the water passed 

 out. 



After arranging the can I immediately put into it 50,000 young shad 

 48 hours old. It had not been running more than ten minutes before I 

 discovered fish were running out the overflow in consequence of the 

 perforated tin at the overflow being too small a surface. I immediately 

 removed the fish and informed Major Ferguson of what had occurred, 

 and gave him my idea of what was wanted for the can. He had the 

 cover of the can made with a larger surface of perforated tin, and 

 this, after putting the 50,000 fish back in the can, I found held the 

 fish. 



June 15. — In the njorning I discovered the fish in Cone No. 1 appear- 

 ing weak, in consequence, as I thought, of the violence of air and water 

 forcing them to top of cone, where the air-bubbles would break and 

 throw the fish to one side. In the course of the day I found the fish 

 were dying. In the can, which I shall designate as No. 3, 1 drew from 

 the bottom of the can about 50 dead fish. The balance of the fish were 

 looking well. 



June 16. — There was a thorough examination made of all the differ- 

 ent experiments. The fish in cones were found to be in about the 

 same condition as the day before. The can, however, I did not find 

 the same. During the night there had been a stoppage of the water, 

 in consequence of which the fish were found all dead. 



June 17. — The fish in Cones Nos. 1 and 2 were five days old. In Cone 

 No. 1, with aerator attachment, the -fish were dying quite fast. My 

 opinion is still the same, that the violence of air-bubbles is too severe 

 for the young fish, and weakens them or wears them out. 



June 18. — I arranged another cone (No. 4) with aerator attachment, 

 and immediately placed in it 100,000 eggs taken the evening before. 

 There was an effort made to use a smaller quantity of water on this 

 cone, but without success. As soon as the water was reduced below 

 23 gallons per hour the aerator would not take in air. Thus it will be 

 readily seen the aerator will not supply the quantity of air with a less 

 amount of water than 23 gallons per hour. This lot of eggs was ex- 

 amined from day to day until all were hatched, and nothing of note oc- 

 curred different from No. 1. 



June 19. — This morning I found the fish in Cone No. 1 all dead. The 

 probable cause was the violence of water and air. The fish in Cone 

 No. 2 were still doing nieely. They were turned loose in the Potomac 

 at 6 p. m. There were 40,000 young shad put in Can No. 3 to again 

 try the aerator. The fish in Can No. 3 did very well until the third 



