© 
52 W. P. Trowbridge on a Submarine Telegraph. 
depressions corresponding to those found upon the face of the dry 
land, what influence will these elevations have upon the practical 
operation of depositing an electric cable, and in the preservation 
of the electric continuity. Upon this point there has been very 
little discussion, on account of the popular belief in the exist- 
ence of a level bottom across the only part of the ocean where 
a submarine telegraph has been supposed to be practicable. 
But even upon the line of the Atlantic udlegréph, although there 
may not exist remarkable submarine mountains and valleys, yet 
it is not improbable that considerable elevations and depressions 
ur. The profile of Capt. ssh peau = -— rect from 
that of Commander Berryman; so m to give rise to 
serious controversies with regard to ab Fatal correctness of 
both, since to the probable uncertainties of the soundings, was 
added the uncertainties in relation to the intermediate depths, 
the soundings being made generally fifty to one hundred miles 
Phe explorations of Dayman and Berryman ought therefore 
to be rega as general reconnoissances only, from which the 
true profile of the bottom can only be conjectured. In the 
explorations of the Gulf Stream by the U.S. Coast Survey, 
Lieutenants Craven and Maffitt discovered, off Charleston, a 
series of submarine ridges and depressions several hundred 
fathoms in height and depth in the horizontal distance of 
twenty to thirty miles. Such ridges and allege would — 
been passed unnoticed in the explorations between Newfoun 
land and Ireland. 
It may be taken for granted that a ‘submarine cable re 
touch the bottom at every point; otherwise some parts of i 
must remain s uspended across valleys, or chasms, © anknown 
depth and extent; under these circumstances its continuity is 
endangered by its ‘weight, its chafing at the points of suspension, 
the action of currents, "and other causes. hether the Atlantic 
cable 0 vealed, b ‘by such influences or not will probably 
never be revealed, but it may be important to examine how 
a more accurate and detailed section of the bottom may diminish 
pe risks which must always attee an enterprise of this char- 
Such ridges and elevations as were found in the Gulf Stream, 
though moderate in height and depth when compared with the 
Pik depths of the eae are yet of sufficient nt etch to 
taken into accou 
