XXXIV. -REPORT UPON APPARATUS AND FACILITIES NEEDED 

 FOR HATCHING SPANISH MACKEREL. 



By J. Alban IviTE, M. D. 



I have tLe honor to submit for your consideration a report upon the 

 following- topics : 



1. The best apparatus for hatching the eggs of the Spanish mackerel, 

 as shown by my personal experience. 



2. The most suitable station for conducting such work. 



3. The best locality for station. 



4. The necessary help and apparatus for conducting the work. 



I will first go over the list of appliances we have used on the Fish Ll:i wk. 

 Iiv July, 1881, the United States steamer Fish Hawk, under command of 

 Lieut. Z. L. Tanner, United States Navy, made her headquarters in 

 Cherrystone Creek, Virginia. The first eggs received were put into 

 the Ferguson cones, which had been previously nickel-plated, to, it 

 was thought, prevent the action of salt water. It took but a few hours 

 to prove this would not answer, for the sulphate of uickel was formed 

 and the fish died; besides the eggs when healthy float, and the current 

 carried them against the gauze sides and aided in the work of destruc- 

 tion. Next we tried the eggs in a cylinder with a flat bottom and an 

 intermittent flow of water maintained by a syphon. The cyliiidei- was 

 coated on the inside with asphaltum. Then copper cylinders with 

 gauze bottoms were used over the side of the ship, and a rise and fall 

 obtained by means of machinery. But in neither instance did much 

 success attend our efforts ; in the case of the cylinders over the side 

 the movement of the waves dashed the eggs against the metal sides, 

 the membranes were ruptured, and death ensued ; had these eggs been 

 free they would have freely ridden the waves with no discomfort. 

 Next, Captain Tanner had a large block-tin cylinder, open at both ends, 

 set in a tub of water ; the eggs were j)laced in the cylinder and the 

 water was delivered into the tub ; nothing was used on the bottom of 

 the cylinder to prevent the escape of the eggs, their buoyancy being 

 found sufficient. 



Things were progressing to our satisfaction, when a white scum was 

 noticed on the surface of the water ; this on analysis was found to be 

 antimony -, the metal had been used to form an alloy with the tin and 

 [1] 1095 



