6 W. P. Trowbridge on a new Sounding Apparatus. 
line; and the _—— practicability of such operations across 
the Atlantic being yet to be demonstrated by new and more 
accurate soundings 
DESCRIPTION. 
The accompanying plate is a photographie copy of a drawing 
peived from the first instrument constructed. Some slight modi- 
ons have since been made in the mode of attaching the 
repwet SP but without affecting the general design. 
PLATE I. 
Fig. 1. Represents the plummet as it appears in its descent. 
T, the tube or case containing the coiled line. - 
W, the leaden or iron weight inserted in the bottom of the tube. 
C, the conical ¢ 
: R, the register in i Bee upon the cap. 
ie the line. 
r, the etter hod 
oy Pe the locks for ova and ungearing the wheels. 
ig. 2a, represents the plar or horizontal view of the register, it being con- 
structed so as to offer the least resistance in passing through the water. 
Fig. ae shows the detailed construction of the register wheels, and the 
foe fig. 1, it will be seen that the form of the apparatus admits of 
rapid motion through the water. The weight is conical and elongated 
and the register presents the edges only, of brass plates to the water, and 
the line being uncoiled and discharged from the fore there is no retar 
ing force to “the descent, from the line itself. Any desired velocity of 
desent may be given to the plummet by increasing or decreasing the 
wei 
Fig. la, shows the method of coiling the line. | 
ere are various modes of doing this which are in eommon practice 
in trios and cotton factories; that which is here exhibited is the method 
und Coil, d he tube. ‘All these rivethods are now practised in 
the factories on a med for winding twine and cotton. 
The qtr siocid be about five hundredths of an inch in diameter 
Le size. A braided line of Holland 
