64 REPOKT OF COMMISSIONER OF FISH AND FISHERIES. [10] 



gill) of impregnated shad eggs were found to contain 3,600, that is, 900 

 per fluid ounce or 26,100 i^er dipper. A deduction of 1,100 was made for 

 water, &c. The above measurements were made with an ordinary apothe- 

 cary's graduate, used in the medical department. 



All necessary preparations having been made for leaving the Susque- 

 hanna, we transferred 300,000 shad eggs to Battery Station, and directed 

 the Herreshoff launch. No. 02, to report to the officer in command for 

 temporary duty. 



At 9.25 a. m., June 5, we left the river for Baltimore, arriving at 2.55 

 p. m. On the following morning the vessel was hauled out on W. Skin- 

 ner & Son's marine railway, her bottom examined, copper cleaned 

 and repaired, propellers painted, and outboard connections examined. 

 The work was completed during the day, and on the following morning 

 the vessel was put into the water, and at 10.35 a. m. left for Washing- 

 ton, where we arrived at 1.40 p. m. on the 8th. 



On the 10th coaled ship, and on the 13th received a special outfit 

 designed for hatching Spanish mackerel. As this work was to be car- 

 ried on in salt water, all metallic surfaces were nickel plated in order to 

 reduce galvanic action to the minimum. At 4.15 a. m., June 14, we 

 left the navy-yard and steamed down the Potomac, arriving off Saint 

 Jerome's Creek at 3.30 p. m., where we were directed to examine the 

 channel improvements and report what progress had been made. Having 

 made the required examination, we steamed off-shore two or three miles 

 and swung ship, with port helm, under steam, observing azimuths on 

 each point for compass error. When the circle was completed with the 

 port helm, we ran into Cornfield Harbor and anchored for the night. 



Launch Ko. 62 arrived from Havre de Grace at 6 a. m. on the 15th 

 and reported for duty. At 6.15 a. m. we got under way, swung ship 

 with starboard helm and, as soon as the observations for compass error 

 were finished, started for Cherrystone Inlet, the launch in company, 

 arriving at 2.30 p. m. 



The pound nets were visited the following morning, but no ripe fish 

 were found, and the fishermen reported that they had seen none during 

 the season. 



We met with better success, however, on the 17th, when 700,000 

 Spanish mackerel eggs were taken and placed in hatching cones with 

 siphon attachment. A small number were placed in a marbleized pan, 

 the water being changed every three hours. About 30 per cent, of the 

 eggs hatched in from thirty to forty hours after impregnation, the tem- 

 perature of the water ranging from 76° to 80o F. The fry were not in 

 good condition and were all dead within a few hours. 



No eggs were procured on the 18th and 19th. On the 20th, however, 

 we succeeded in getting 240,000, a portion of which were placed in an 

 ordinary hatching cone and treated as shad eggs, the remainder being 

 distributed among the various forms of cylinders. They commenced 

 hatching twenty-four hours after impregnation, but the fry were not 

 strong and many of them died. 



