° 
W. P. Trowbridge on a Submarine Telegraph. 51 
Art. VI. par the importance of more ane and more accurate 
aes sea Soundings in connection with the successful establishment 
a Submarine Telegraph across the Atlantic; by Prof. 
Pacwenuor, Assistant U. S. Coast Survey. 
In - year 1849, two citizens of Philadelphia, Horatio Hab- 
bell, Esq., and Col. John H. Sherbourne, presented a lengthy 
memorial to Congress promulgating a plan for establishing tele- 
graphic communication across the Atlantic ocean; and asking 
the Government to aid in carrying out the project. This memo- 
rial contained the announcement of the probable existence of a 
table-land or plateau between Newfoundland and Ireland, in the 
following words. 
“Your memorialists proceed to say that from many observa- 
tions which have been made, there is incontestible evidence of 
the existence of a submarine table land extending from the 
of the British Channel.” “This is proved by the altered color 
of the sea water, which has a different appearance, in unfatho 
able places, from what it has in shallow s spots.” “This combined 
with the volcanic construction of Iceland and the Azores, an 
the situation of that portion of the ocean that. lies between these 
‘oe groups, has led to the conclusion that there has been a 
cut wear in man ey places, by deep-water cheater * The 
appeara Medusz, Polypi, and other marine creation: seen 
upon the ath of the discolored water, strengthens this opinion.” 
“ Your memorialists propose that these suggestions should be 
investigated,” &c. 
The first experiments made to test the truth of these sugges: 
tions were the soundings of Commander Berryman, made in the 
summer of 1853. Previous to this time no cast of the deep: 
Hubbell and Sherbourne. In a popular sense this announce- 
ment conveyed the idea of a vast unbroken level at the bottom 
of the sea, the existence of which has not been conclusively 
established by the soundings referred to. 
he question, however, is one of very little importance, pr 
ded the irregularities of the bottom do not offer any serious ha 
stacle to the safe descent of an electric cable, or cause its destruc- 
tion subsequently. The question now presented is, taking the 
bottom of the ir as it probably exists, with elevations and 
