176 BULLETIN OF THE 
in making each one hundred turns during soundings, — noting the state 
of the sea, etc.,—as the best way to gain a knowledge of the rate at 
which it is safe to let the wire pay out under different circumstances. 
In a smooth sea there will be very little trouble, and probably with the 
new machine there will be none in the heaviest sea in which soundings 
can be taken; but sounding with wire having a tensile strength of 240 
Ibs. is a delicate operation even with the best apparatus, and the person 
in charge, should he lack experience in sounding with wire, would do 
well to keep, at first, well within the bounds of safety, and then to 
approach gradually the limit of theoretical possibilities. If everything 
is working well and the wire keeping taut at all times, it is of course 
safe if the correct amount of resistance has been applied to the reel 
according to the rule, 
Sounding-Rod, composed of Sigsbee’s Detacher used in connection with a 
modification of Captain Belknap’s Cylinder No. 2. 
Dusoription or PARTS, 
A cylinder, a, with screw-joint at B. 
A casting composed of the cylindrical guides C, C and the perforated 
plate J. 
The valve seat 7. 
The popper-valve F, connected rigidly to the pipe G, which slides freely 
on the lower guide C. 
The weak spiral spring H. 
The hollow cone J, to the bottom of which is soldered the smooth cylin- 
drical plate D. 
A detacher composed of the swivel K, the pawl Z, the tumbler M, and 
the spring N (No. 14 American-gauge brass spring wire). 
The perforations P, P, etc., for the escape of water. 
In connection with the above is used the iron shot-sinker Q, fitted with 
the iron wire bail R, 
WORKING. 
During the descent the cone J is kept up by the shot as shown in 
Figs. I. and IL, and on striking bottom the bail is prevented from get- 
ting over the top of the detacher by the bearing which the sinker has 
against the under part of the cone. 
When the sinker strikes bottom the slacking of the sounding line or 
wire trips the tumbler, and the sinker is free to slide off the cylinder. 
