[li] WORK OF THE STEAMER FISH-HAWK. 65 



We deposited 120,000 fry in Cherrystone Inlet on the 22d and on the 

 23d procured 300,000 eggs, which were placed in the various hatching 

 apparatus on board. The temperature fell suddenly nearly ten degrees, 

 which retarded the development, the first young fry appearing thirty- 

 nine hours after impregnation. About 60 per cent, of the eggs hatched 

 and the fry were in much better condition than any of the previous lots. 



Three hundred thousand eggs were procured on the 25th and placed 

 in cones and cylinders. About 75 per cent, hatched, but those in the 

 cones soon died. 



We were unable to account for the loss of fry hatched in cones and 

 the survival of those in the cylinders, unless we attributed it to galvanic 

 action. The cones above mentioned were copper, nickel plated, and 

 after a few hours' service in salt water the entire submerged surface 

 was covered with a dark deposit which we thought was sulphate of 

 nickel, to which was attributed the great mortality among the fry hatched 

 in the cones. 



Among the cylinders used was one of block-tin, in which the largest 

 proportion of eggs were hatched, and the fry seemed to be in better con- 

 dition. In this vessel we had a light whitish deposit which we called 

 sulphate of antimony, but it did not seem to have an injurious effect on 

 the eggs or fry. 



One hundred thousand young fish were deposited on the 26th, 50,000 

 on the 27th, and 100,000 transferred to the Lookout on the 28th for ex- 

 perimental purposes. 



Mr. Marshall McDonald, of the United States Fish Commission, 

 arrived on the latter date to continue the experimental work, the Fish 

 Hawk being required for other service. Such articles as he required 

 were landed, launch No. 62 turned over to him, and at meridian on the 

 29th we left for Washington. We had at this time about 5,000 young 

 fish which I had placed in a glass aquarium soon after they were hatched, 

 where they had remained ninety-six hours without change of water. Very 

 few died in the meanwhile, and those that were alive were strong and 

 vigorous. There were about ten thousand in a hatching cylinder, and 

 they were placed in a glass jar for transportation. They were in good 

 condition until about 3 p. m., when we encountered a furious squall in 

 Chesapeake Bay, with very heavy thunder and incessant lightning. 

 From that time they showed signs of distress, and before morning were 

 nearly all dead. 



We anchored for the night at Lower Cedar Point, and arrived at the 

 Washington navy-yard at 9.50 a. m., June 30. Active preparations were 

 made for the summer's cruise ; hatching apparatus was landed and the 

 dredging outfit taken on board. 



The last of the young fish in the aquarium died on the Ist of July, 

 having been one hundred and forty-four hours without change of water. 



At 2.10 p. m., July 7, we left the navy -yard for Wood's Holl, Mass., 

 passing Cape Henry at 8.40 a. m. on the following day. A fresh north - 

 S. Mis. 110 5 



