1096 REPORT OF COMMISSIONER OE ETSTI AND FISHERIES. 



m 



increase its strength. Many of the fish died, but, notwithstanding the 

 baneful effects of the salts of antimony held in the water, the apparatus 

 was so efficient that we were enabled to hatch out 50 per cent, of the 

 eggs, and to keep the young fiish for several days. The experiment 

 was left unfinished when orders came for our departure. Yet oar ex- 

 periment taught us (1) to have, if possible, no metal come in contact 

 with the water containing eggs or fish; (2) to give j)lenty of light; (3) 

 that the eggs would not hatch properly when the temperature was 

 below 78° F., nor could they survive a rise or fall of several degrees, 

 even though the teiaiperature was high. 



In the summer of 1883 the United States steamer Fish Hawk, com- 

 manded by Lieut. W. M. Wood, United States ISTavy, made a cruise in 

 Cheasapeake Baj^ to experiment with and devise an apparatus for 

 hatching the eggs of the Spanish mackerel. A few eggs were obtained 

 at Kew Point, but the larger part were taken on the eastern shore, at 

 the month of Cherrystone Creek, near the light-house. 



Mr. Smith and myself having had some experience, as related, re-m 

 quested that some half dozen glass aquaria be furnished, and we devised 

 an apparatus of which an idea may be formd from Fig. 1. The aquaria 



Fig. 1. — Aquarium for hatcliing Spanisli mackerel. 



gave us a large water surface with convenient depth, and into it from 

 our tanks we allowed a flow of water ; this was conducted from the 

 tank to the aquaria by rubber tabing which passed over a piece of five- 

 eighths-inch glass tube which in turn passed to the bottom of the 



