314 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
when, tlie stern being high in the air on the crest of a wave, it suddenly descends to 
the hollow of the sea with a velocity little inferior at times to the sinking of a 
sounding shot. This violent motion, under exceptional circumstances, is the only 
disadvantage of moment in placing the sounding machine at the stern, but with the 
Sigsliee machine it assumes little importance in comparison with the suiierior 
advantages of the location. 
The accumulator springs, in connection with the scale, indicate the rapidly varying 
strains on the sounding wire during the descent of the sinker, and apprise the 
operator of the instant it strikes the bottom. 
The caj) h is a neatly fitted, water-tight, copper cover iirotecting the interior 
surfiices of the accumulator tiibes, springs, roiie, and pulleys from the weather. It 
is held in place by thumbscrews which are readily removed. 
The acemmilator pulley I is lightly constructed of brass, has a deep groove for 
the wire, and is mounted in such a manner that it can be readilj^ removed from its 
bearings without displacing the frame. Guards of sheet brass are hinged to the frame 
above the pulley and carefully shaped to its surface, where they are held in place by 
delicate spiral springs to prevent the wire from jumping out of the groove in case it 
is suddenly slackened from any cause. 
The east-steel frame within which the pulley I is suspended is lightly constructed 
also in order to reduce its inertia to the lowest limit. The cross heads traverse freely 
on steel guides which are secured to the inner surfaces of the tubes t, along their 
whole length, giving to the pulley a vertical motion equal to the elastic limit of the 
accumulator springs, which is about 4 feet. Shoulders project from the pulley frame 
which imiiinge upon the spur buffer below, or springs above, to guard it from violent 
shock in case either the sounding wire or accumulator rope should break under heavy 
strain. 
The spur hiiffer stands in a vertical position on the forward end of the frame h 
directly under the projecting, shoulder of the frame which carries tlie pulley I. It 
consists of a steel tube containing a spiral compression spring, upon which a steel 
piston rests, its upper end projecting 2 inches above the tube, thus providing a safe 
cushioiung for the accumulator imlley and frame in case the springs or accumulator 
rope should give way under tension. 
The spring Imf'ers are V-shaped steel springs on the middle lower surface of the 
tie-frame, each side of the accumulator rope. They are intended as a cushioning for 
the frame and pulley I in the event of-the sounding wire parting under a heavy strain. 
The fair-leader and swivel pulley m guide the sounding wire to the accumulator 
pulley, the former when the wire is nearly vertical, and the latter when the angle 
is great, as would be the case when the vessel was drifting, turning, or steaming 
ahead. 
The fair-leader is a cylinder of tempered steel, with rounded ends, bolted to the 
outboard end of the frame with its center directly beneath the outer score of the 
accumulator pulley. The swivel pulley has a deep groove for the wire, is of brass and 
very light; its steel frame is bolted to a collar that turns freely on the outer surface 
of the fair-leader in such a manner that the bottom of the groove on the inner periphery 
of the pulley ui retains its position at ail times directly beneath the outer score of the 
pulley I and center of the fair-leader. 
The swivel pulley is indispensable when reeling in the sounding wire with the 
