54 W. P. Trowbridge on a Submarine Telegraph. 
will not only be an unnecessary waste of cable in some places, 
but the surplus may fail to be sufficient in others, the result of 
which might be a rupture. 
On the other hand, provided an accurate and detailed profile 
of the bottom be constructed, from which the exact length of 
cable required between any two points, however near together, 
be determined, there is no reason why an irregular form of 
bottom should present any serious obstacle to the safe deposit of 
a cable, provided the speed of the ship be so regulated as to de- 
posit the proper amount in the proper place; and it is only by 
following this rule that risk of breaking from the weight of the 
cable can be avoided. 
In conclusion, the following rules may be stated. 
1. Soundings of unquestionable accuracy should be made at 
intervals not greater than ten miles, and where there is a steep 
slope of the bottom, at more frequent intervals. 
2. From these soundings a profile of the bottom should be 
- made, in sections, upon a large scale, from which the length of 
the curve of the bottom may be calculated. 
8. A chart should be constructed based upon the profile, 
showing the rate of speed and delivery between the different 
stations, in order that the cable paid out may adapt itself without 
tension to the curve of the bottom: 
the two continents notwithstanding the supposed rugged char- 
acter of the bottom near them; while there is yet no proof that 
the bottom between the Azores and the Banks of Newfoundland 
is at all unfavorable to such a project. 
& 
