W. P. Trowbridge on Deep Sea Explorations. 389 
Omable depths, stands the sounding of Captain Denham of the 
. British Na , in H. M. 
4 voyage from Rio de Janeiro to the Cape of Good Hope. This 
18 an extreme case, but since it is reported among the greatest 
p-sea casts, it will serve best for illustration.* All other great 
of are subj the same 
l some in a less degree; so that it is not necessary for us to 
believe, yet, any thing with regard to them, except that they 
gave no result. The sounding of Captain Denham was made 
of an inch in diameter; and it is reported that this lead de- 
Scended to the depth of nearly nine miles in the sea without 
touching bottom. : 
In accordance with a plan which originated with the lamented 
G. M. Bache, United States Navy, in 1846, in the explorations of 
the Gulf Stream, and which has constantly been followed since 
aptain Denham noted the time of running out of the successive 
Portions of the sounding line during the nine hours of its sup- 
Posed descent. According to these observed times of descent 
_ the nine pound lead communicated to the descending line at the 
depth f 3,000 fathoms or 18,000 feet a velocit of two feet per 
Second; a result which is philosophically jcsare, Oe since the re- 
: fr qlieut. Maury diseases these deep cose ns ote atRaciary. his rules 
ve at the depth do not seem to me to be entirel; 
