92 REPORT OF COMMISSIONER OP FISH AND FISHERIES. [90J 



THE CHESTER RAKE DREDGE. 



Plate XLIX, Fig. 2, shows the Chester rake dredge designed for the 

 purpose of obtaining mollusca, annelids, Crustacea, &e., which burrow 

 beneath the surface out of reach of any other apparatus in use by the 

 United States Fish Commission. 



The rake is shackled to the dredge rope, and a Blake dredge, secured 

 to eyebolts on the rear of each end of the frame, following it as it is 

 dragged over the bottom, picking up whatever is turned over by its 

 strong harrow-like teeth. 



DIMENSIONS OF THE CHESTER RAKE. 



Frame : 



Length, 3 feet. 



Depth of opening, 10 inches. 



Width of metal, 2-J inches. 



Thickness of metal, one-half inch. 

 Teeth : 



Length, 7 inches. 



Width of base, pointed, 2-J inches. 



Thickness of metal, base, one-half inch. 

 Arms: 



Length of long arm, 3 feet 5 inches. 



Length of short arm, 3 feet 3 inches. 



Diameter, round iron, three-fourths of an inch. 

 Weight, 79 pounds. 



This admirable instrument was devised by Capt. H. C. Chester, to 

 whom the Commission is indebted for many practical suggestions as 

 well as for some of its most valuable apparatus. 



BOAT DREDGE. 



The boat dredge is essentially a miniature form of the ordinary ship's 

 dredge already described, and is designed for use from boats where it 

 must be worked by hand. 



DIMENSIONS OF THE BOAT DREDGE. 



Jaws: 



Length, 1 foot 7 inches. 



Width, 2| inches. 



Opening, 7-J inches. 



Angle, 12 degrees. 

 Stud: 



Length, 6£ inches. 



Diameter, round iron, five eighths of an inch. 

 Bridle : 



Diameter, round iron, one-half inch. 



Length, 1 foot 5 inches. 

 Weight, 15 pounds. 

 Net: 



Length, 1 foot 8 inches. 



Size of mesh, square, three-sixteenths of an inch. 



Material, cotton, 3-thread, bottom double. 

 Shield : 



Length, 2 feet 8 inches, 



Material, No. 3 cotton canvas. 



