4 W. P. Trowbridge on a new Sounding Apparatus. 
And the motion of this line in an extended form in the water 
must be avoided. 
The apparatus which I have devised is designed to secure this 
object,—by attaching to the sinker a tube or case in which the 
sounding line is compactly coiled, and from which it will be dis- 
charged freely, thus causing the plummet to carry down the coil, 
while one end of the line is held fast at the surface; the line 
being uncoiled from the descending sinker in the manner that a 
spider falling from a height gives out a thread in his descent by 
which he retains communication with the point above to which 
the thread is attached. The motion of the line in an extended 
form through the water being thus avoided, all the conditions of 
free descent are secured, and the plummet will descend to the 
greatest depths with a rapid and uniform velocity 
The depth is ascertained in the manner faretolevs known. as. 
Massey’s method, by a helix or curved blade, which is caused. 
to revolve, b the motion of the apparatus through the water. 
Instead of assey’s indicator however, which from its faulty 
construction does not give accurate results, I have adapted Sax- 
ton’s Current Metre, a much more delicate instrument, to this 
specimen tube is also used differing somewhat from those 
now in use, in construction but not in its essential points. 
The lower end of the line is attached to the register and to the 
specimen-box which weigh yaa: only two or three pounds, 
and as the line is hauled in from the bottom it brings up the 
register and spon DO leaving the plummet and attached 
case at the botto 
py details of construction are shown in the accompanying 
and description of the apparatus. 
as es overcoming the principal difficulty in sounding, there 
re other important advantages secured by this arrangement 
sik simplify rather than complicate, the problem. T are 
as follows: 
First, there is no strain upon the line, in the descent, except 
from its own weight, no matter to what depth or with what 
velocity, the plummet may descen 
It is possible therefore to employ a very small line; a or a 
thread of silk may in fact be extended to the bottom 
ocean. This permits of the use of a line, which may be coiled 
compactly within a small space, the a of the line being 
made just sufficient to insure its being hauled in with safety, 
inging up at the same time the spesimen:ox atl the register. 
The strain incaght upon it, in hauling in, will depend upon the 
Yer oe upward motion, which may be tegueete ac- 
a. 
