W. P. Trowbridge on Deep Sea Soundings. 161 
length of which, compared with the diameter of their cross sec- 
tion was not very great; and it will be at least interesting to 
know whether this law is true with reference to a line of great 
length and small diameter; and especially when this line is sub- 
jected to the great pressure which is exerted upon it in the 
depths of the ocean. The resistance in this case is entirely due 
to the velocity which is imparted to a certain quantity of water 
_along the line, by its motion, and not to friction in the ordinary 
sense of the term. If the resistance from friction be at all con- 
sidered, it must increase greatly with the depth, since the pres- 
sure is increased by fifteen pounds on every square-inch for 
every thirty four feet in depth. It will be seen by the subse- 
oe discussion that the pressure has no influence in increasing 
_ the resistance. 
gain, the density of the water at great depths, as affected by 
the compressibility of that fluid, must be considered, and also 
earth; and the discussion of the subject should enable us to 
determine the best means of overcoming the difficulties which 
ng 
about seven hundredths of an inch in diameter, and ble of 
ing a strain of 60 pounds; the weight of 100 ms, in 
The mode of observing was as follows: several thousand 
-obable that in many instances the drift of 
iderable, yet the mean results of the experi- 
peas pe Staae Lee and ryman from observations ex- 
iriclan at years, differ only by a small constant 
quantity which is inappreciable in the determination of veloci- 
ties to the depth of 1000 fathoms; and below this the difference 
is still slicht, I have therefore made use of the experiments of 
es 
ge 
