2 W. P. Trowbridge on a new Sounding Apparatus. 
ance” as it is calléd by Prof. Airy, was known to exist, but the 
amount of this endwise resistance in pounds, and its “ultimate 
effects at great depths, had not been etermined, It was sup- 
posed that by making use of a weight of thirty or forty pounds 
and a small fishing line, this resistance would be deoaet to an» 
inappreciable amount, or at least that its effect in retarding the 
descent of the lead would not be sufficient to destroy confidence 
- in the results 
t appears, “however, from the investigations referred to, that 
a weight, such as is ordinar ily used in sounding, will be practi- / 
came held in suspension at no very great depth, even when the 
used is the smallest that will nae the weight with safety 
in Eihea air; and in confirmation of this conclusion, the fact is 
well aaa that, notwithstan created experime 
made by the ost skillfu 1 officers and with the utmost care, t 
bottom of deed ocean has never been reached in its deepest parts; 
and even where the bottom has been attained and specimens 
brought to the surface, the uncertainties of the results have given 
good grounds for controversy with regard to the depth. 
These failures and oe do not arise from the magni- 
of the distance to be measured, nor from the impenetra- 
y of the fluid through hih the lead has to pass: distances 
‘“ Samay great and infinitely small in the universe above and 
around us, have been measured with precision; and the unex- 
plored desis of the ocean are occupied by a medium freely and 
equally gine at all depths. Ye t in this field, a field daily 
traversed by the commerce of the world, a distance of a few 
miles only has‘ baffled all attempts to measure it. 
The difficulty hes in the simple cause stated above, viz. the 
“ endwise resistance” or friction upon the sounding line, which 
prevents the lead from going to the bottom where the depth is 
great. 
The apparatus which I have devised, is designed to avoid this 
friction upon the line, M hile at the same time the line i 4 not dis- 
pensed with, but is made use of, as in the ordinary m 
~~ Before deseribing this apparatus I will briefly refer Re some of 
the results given in my previous report on this subject. 
The rate of descent of an iron globe or sphere, as the simplest 
geometrical form, was first determined when falling ge in nthe 
ocean, and it was found that a sphere will attain a certain ma 
mum velocity, within twenty-five feet of the surface, which ve- 
5 Sem be kept up without sensible increase or dimin: atic to 
tto 
E ae ioe shot this uniform. velocity is about aitees 
. ic Bit when a small line is attached to the 
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a ied sie with at were then discussed, the line : : 
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