[71] FISHERIES OF THE UNITED STATES. 583 



a. drum one fathom in circumference (less the small allowance for the 

 diameter of the wire), and with a V-shaped friction score at the side, 

 is rigidly attached to its axle and mounted upon standards. On the 

 axle is a worm which engages a counter or register to mark the revo- 

 lutions of the reel. The wire, which is wound about the drum, pays 

 out directly from the reel, through a fairleader or clamp on the forward 

 end of the bed-board into the water. In the rear of the reel, and on the 

 same side as the friction score, is a dynamometer pulley or wheel hav- 

 ing two scores, which we will call the wide score and the narrow score, 

 respectively. This is mounted in a special standard, from which it may 

 be removed at will. For paying out wire, an endless rope belt, called 

 the brake cord or the friction rope, is passed somewhat more than half 

 around the friction-score of the reel, thence one whole tnrn around the 

 wide score of the dynamometer pulley, and through a tail-block to the 

 rear. The pendant of the tail-block, or, more strictly, pulley, being rove 

 through a standing block, supports weights to tighten the friction rope. 

 The narrow score of the dynamometer pulley is connected with a spring- 

 scales by a tangent wire or cord in such a way that the traveling of the 

 belt can tnrn the pulley on its axle only to the extent permitted by the 

 resistance of the spring-scales. When the reel is set in motion, the re- 

 tardation of the belt on the dynamometer pulley places a resistance 

 upon the reel that can be regulated by weights at the tail-block. The 

 scales are intended to show approximately the amount of resistance 

 applied to the reel by means of the belt." 



The Tanner Sounding Machine, for sounding in moderate depths of water 

 with piano-forte wire, on the principle of Sir William Thomson. 



United States Fish. Commission. 



This instrument works on the plan of Sir William Thomson, and is a 

 simplification of the Sigsbee sounding machine, for use in moderate 

 depths of water ; the reeling in is accomplished by hand. It was de- 

 vised by Lieut. Z. L. Tanner, United States Navy, in 1880, for the 

 steamer Fish Hawk, then engaged in dredging along the cost, in all 

 depths down to 500 or 600 fathoms. The reel is of tough composition, 

 is fitted for holding a considerable supply of sounding wire, and is fur- 

 nished on one side with a groove for the friction line by which it is con- 

 trolled. It rests in a composition brass frame, cast in one piece, and 

 surmounting a wrought iron standard which ships in the rail. Above 

 the frame, into which it is fastened between two lugs, extends a curved 

 arm of flat bar iron, carrying at its outer extremity a small, grooved, 

 brass pulley, working in guides and suspended by a coiled spring which 

 allows several inches of vertical play. A brass guard is fitted over the 

 upper portion of the pulley to prevent the wire from flying off if suddenly 

 slacked. The reel is worked by friction motion, by means of a handle 

 or crank on each side. Both of the cranks have friction surfaces, which 

 are brought into action by moving the right one half a revolution ahead, 

 the left remaining clamped, or being held firmly in the hand. The re- 



