294 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
supplied with u large quantity of rope, steam reel, aud other appurtenanees, and, in 
addition, one of Sir William Thomson’s machines for sounding- with wire. It was 
furnished by order of Commodore Anunen, chief of the Bureau of hfavigation, who 
rightly appreciated the great value of Sir William’s invention, in spite of the crude 
and imperfect form of the original machine and the cold reception given it by the 
ChaUcnger. He Avas familiar with Thomson’s experiments, thoroughly understood 
the preeminent qualities of pianoforte wire for deep-sea sounding, and wisely trusted 
to Belknap’s enterprise and inventive geniirs to suiiply any deficiencies that experi- 
ence might develop in existing aiipliances. 
Brooke’s apparatus was designed for use with rope, as were all devices known at 
the time, and the production of a simple form of sounding rod and detacher fuliilling 
jnodern requirements Avas one of the first and most important problems Belknap had 
to solve. He retained the Brooke principle, modified the detacher A^ery .slightly to 
better adapt it for use AAdth wire, increased the capacity of the cup or cylinder in 
order to bring up a larger bottom specimen, substituted a metal iioppet-valve in place 
of the goose qnills, provided for a free circidation of water through the cylinder 
during its descent, and protected the bottom specimen from wash during the ascent. 
It AA-as introduced by the inventor as the Belknap deep-sea sounding cylinder Ho. 2, 
was successfully used throughout the extended cruise of the Tuftcarora., and became the 
standard sounding cylinder for deep-sea work in the United States Na\^y and the Coast 
Survey. 
THE BELKNAP DEEP-SEA SOUNDING CYLINDER NO. 2. 
The cylinder, casting, valves, and valve seats are brass, the rod and detacher of 
wrought iron or steel (plate XA' ). The detacher is so proportioned that the lip receiv^es 
the wire bail and carries the weight of the sinker in exact prolongation of the axis of 
the cylinder, thereby maintaining it in a vertical x)Osition until the tension is removed 
by the sinker resting on the bottom; theAvire is then slackened, alloAving the detacher 
to fall by its own gravity, slipping the wire bail and releasing the AAmight, Avhich has 
carried the cylinder SAviftly down and pressed it into the bottom soil to receive its 
specimen. 
The cylindrical casting has a screw at its upper extremity l)y which the rod is 
attached. The upper cylinder head and valve seat are formed by an expansion of the 
casting near its center, and a small shoulder a fcAv inches beneath it holds the lower 
vahm seat in place. The spiral spring and poppet-valve stem are contained A\dthin a 
cylindrical chamber Avhich serves as guide for both. 
The upper and lower valves have free A^ertical moATinent; they are faced Avith 
leather to insure their being tight, aud the valve seats are provided Avith apertures 
for the free circulation of water dirring the descent, Avheu the valves are all kept open 
by the upward rush of Avater through the cylinder, and promptly closed by reverse 
action when the upward movement begins, thereby preventing the wash of the bottom 
specimen in the barrel of the cylinder. 
The spiral spring is delicately adjusted to retain the poppet valve on its seat 
Avithout undue resistance to external pressure, and the adjustable screw stud projecting 
beloAv the cylinder is intended to lacilitate the o]iening of tlie poppet Amive, and is of 
.service oidy on hard, sandy bottom. Tlie bottom specimen is removed by uuscreA\dug 
tlie cylinder from the casting at c. 
