W. P. Trowbridge on Deep Sea Soundings. 169 
velocity, for different velocities, or what is the same thing, dif- 
ferent depths, and compare tlrese differences of length with the 
differences of resistances, the resistances appear to diminish with 
the depth. This is particularly the case with the deep sea line 
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ve seen the change of density is so small that no sensible in- 
crease of resistance to motion among the particles, is produced. 
This fact I do not consider conclusively shown by the investi- 
gation, for although in the last two columns of tables VI, VUI 
ie numbers expressing the ratios of resistances when compared 
with the ratios of the lengths, appear to diminish with the depth, 
yet from a want of knowledge of the diameter and specific grav- 
ity of the lines used, it is impossible to detect very slight varia- 
tions in the resistances. The conclusion is a natural one, how- 
ever, that the diameter of the line being diminished by the com- 
— pressure and tension, the resistance will diminish with the 
epth, 
The observations which I have discussed are not sufiiciently 
numerous to determine with certainty the influence of increasing 
or diminishing the diameter of the line. Taking the deep sea 
vin 
appear to be proportional to the diameter. ‘Table oe 
diameters were probably as 1 to 8 or 4, but the diameter of the 
ae sea line was not exactly given, a a 
_ The resistance of the water upon a sounding line, may there- 
fore be represented by the following expression, 
R=(constant)xW 8.1.0, 
in which S represents the cross section of the line, 7 the length, 
and v the velocity. : 
€ constant must be determined by experiment. ; 
From these results we are justified in drawing the following 
the whole resistance at great depths, its form is not a matter of 
d, With 
the experiments with 
ame so great at 
