[57] FISHERIES OF THE UNITED STATES. 1211 



Ferguson hatching- jar — Continued. 



series of jars before it finally escapes. The jar is used chiefly 

 for hatching eggs of the salmonidse. It holds about 4,000 sal- 

 mon eggs or 6,000 trout eggs. 



C. APPARATUS WITH A DOWNWARD CURRENT. 



Clark's hatching -trough. 



Model. A section of the Clark hatching-trough, supported on 

 wooden standards, showing two compartments complete. Each 

 compartment contains a hatching-box, the bottom of which is 

 perforated with holes and raised slightly above the bottom of 

 the trough by means of wooden standards to allow the es- 

 cape of water from beneath. Each hatching-box contains 12 

 trays of wire cloth y on which the eggs remain during their de- 

 velopment. Compartments, 15 inches long, 12 inches wide, 12 

 inches deep — inside measurement. Hatching-boxes, 13J inches 

 long, 12 inches deep, and 11 inches wide — outside measurement. 

 Trays, 12 inches long, 9 inches wide, and f of an inch deep. 

 Patented by Nelson W. Clark, Clarkston, Mich., March 3, 1874. 

 Presented by Frank W. Clark. 42,812. A Clark trough usually 

 contains 10 to 20 compartments, each being separated from the 

 adjoining one by "means of a partition, which is notched at the 

 center and provided with a tin spout for conducting the water. 

 The trough is placed at a slight incline and the water, entering 

 the first compartment, passes down through the trays of eggs, 

 out at the bottom of the hatching-box, and up around its sides 

 and ends on its way to the second compartment, all of the water 

 passing through each box before it finally leaves the trough. 



APPARATUS FOR SEMI-BUOYANT EGGS. 

 a. APPARATUS UTILIZING RIVER CURRENTS. 

 BRACKETT'S HATCHING-BOX. 



A rectangular box of wood, the front end of which slopes inward 

 at an angle of 45° for the purpose of deflecting the current. 

 The bottom is covered with wire cloth and the water is forced 

 through it by means of a tide-strip attached to its further edge. 

 Length, 22 inches ; width, 20 inches ; depth, 12 inches. Pat- 

 ented by Edward A. Brackett, Winchester, Mass., February 8, 

 1876. 26,904. Presented by Edward A. Brackett. 



Green's hatching-box. 



The original box in which Seth Green made his first experiments 

 in hatching eggs of the shad. 26,903. Patented by Seth 

 Green, Bochester, N. T. Gift of Seth Green. 



