e;
but the company could not avail itself, at that time, of the instruments
or apparatus for testing its conducting power and insulation, in the
manner since pointed out by experience. The effects of temperature,
as we have seen, were not provided for. The vast differences in the
conducting power of copper were discovered only by means of that cable,
when made. The mathematical law whereby the proportions of insulation to
conduction are determined had not been fully investigated; and it was
even argued by some of the pretended electricians in the employ of the
company, that, the smaller the conductor, the more rapidly the current
could pass through it. No mode of protecting the external sheath from
oxidation had then been discovered; and the kind of machinery necessary
for submerging cables in deep water could only be theoretically assumed.

Looking back to that period, and granting that there was too much haste
in the preparations, and that other mistakes were committed which could
now be foreseen and avoided, it is not too much to say, that, if that
cable could be laid and worked, as was done, after one failure in 1857,
and the consequent uncoiling and storage of it in an exposed situation,
and after three attempts in 1858, under the most fearful circumstances
as to weather, it would be an easy task to lay a cable constructed and
submerged by the light of present experience.

[Illustration: The Cable laid in 1858.]

[Illustration: The proposed New Cable.]

The above cuts, representing sections of the cable laid in 1858 and the
proposed new cable, will serve to show the difference between the two,
and the immense superiority of the latter over the former. In the old
Atlantic cable the copper conducting-wire 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_. Now the size,
or diameter, of a telegraphic conductor is just as important an item, in
determining the strength of current which can be maintained upon it with
a given amount of battery-force, as the length of the conductor. To
produce the effects by which the messages are expressed at the end of
a telegraphic wire or cable, it is necessary that the electric current
should have a certain intensity or strength. Now the intensity of the
current transmitted by a given voltaic battery along a given line of
wire will decrease, other things being the same, in the same