sr diate SO a +s <. ig eae 
160 W. P. Trowbridge on Deep Sea Soundings. 
practical difficulties which have been met in applying the ordi- 
nary methods; but the methods which are most naturally ad 
ted for Feel ‘depths fail when the depth is very great, on ac- 
count of their eeapee in the latter. case. 
It is important to separate those difficulties which may be 
overcome by skill and ie from those which under the 
most favorable circumstances and conditions, are still as great as_ 
ever, and depend only upon the mechanical forces developed; | 
and of course some proof will be required to show that the ob- 
stacles presented by the latter causes are, in the present mode of - 
ble 
sounding, almost if not quite insurmounta 
If we suppose the water of the ocean to be in a state of rest, 
a sounding weight and line will descend according to the laws 
which govern the falling of heavy bodies in a resisting medium 
the combined weight of the sinker and line, in the water, being ~ 
the accelerating force, and the resistance offered by the water to 
the motion of the weight and line, the retarding force; and upon 
the relative magnitudes of these forces the circumstances of 
descent will depend. 
sinkers acini pees in sounding; and a numerous exper 
ments in deep sea sounding, to which reference has been made, 
especially those of Lieutenants Lee and Berryman, U.S. Navy, 
afford the means of determining the resistance of the water upon 
e line. 
In these latter experiments the rate of descent _ accurately 
observed and the results of numerous trials, i different 
weights attached to the same line, and with diferent fae fur- 
e means of ascertainin e the velocity of in 
h accuracy to determine all the circumstances 
tion. 
The problem then becomes one of the most simple in mechan- 
ies, viz.: having given the space, time, and velocity corres 
ing to the fall of a given weight in water, to find the law of 
SSI; stance to the motion. 
ssp as of any body, in water, under 
sh known to be proportional to to the squares of 
case, at every point of the path deseribed by the fa falling Body, Z 
as sufficient 
ees to the m the problem isa new one. Although the : 
on W ch ee = was 
m a the 
