and continual dispersion of the statical electricity with which the wire
is charged along its whole length.

It was mainly owing to the retardation from this cause that
communication through the Atlantic cable was so exceedingly slow and
difficult.

I will now endeavor to show why the new cable will not be liable to this
difficulty, to anything like the same extent.

I have alluded to the resistance offered by the conductor of a
telegraph-cable to the passage of an electric current, and to the
retardation of this current by static induction. The terms _retardation_
and _resistance_ are not considered technically synonymous, but are
intended, as electrical terms, to designate two very different forces.
The resistance of a wire, as we have seen above, is proportional to its
length, and inversely to its diameter. It is overcome by increasing the
number of cells in the battery, or, in other words, by increasing the
intensity or force of the current. The retardation in a telegraphic
cable, on the contrary, is proportional to the length of the
conducting-wire and the intensity of the battery. In the former case, by
increasing the electrical force you overcome the resistance; while
in the latter, by augmenting the electrical force you increase the
retardation.

From the foregoing law it will be seen that there are two ways of
lessening the resistance upon telegraphic conductors,--one by reducing
the length, and the other by increasing the area of the section of the
conducting-wire. Now, as already remarked, the copper conducting-wire in
the old cable weighed but ninety-three pounds to the mile, while in the
new cable it weighs five hundred and ten pounds to the mile, or more
than five times as much. If, then, by comparison, we estimate the
resistance in the old Atlantic cable to have been equal to two
thousand miles of ordinary telegraph-wire, the increased size of the
conducting-wire of the new cable reduces the resistance to one-fifth
that distance, or four hundred miles. And while it required two hundred
cells of battery to produce intensity sufficient to work over the two
thousand miles of resistance in the old cable, it will require but
one-fifth as much, or forty cells, to overcome the four hundred miles
of resistance in the new cable. The retardation which resulted from
the intense current generated by two hundred cells will be also
proportionately reduced in the comparatively small battery of forty
cells. Thus we