[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 proportion as the length of the wire increases.  Thus, if the wire be continued for ten miles, the current will have twice the intensity which it would have, if the wire had been extended to a distance of twenty miles.  It is evident, therefore, that the wire may be continued to such a length that the current will no longer have sufficient intensity to produce at the station to which the despatch is transmitted those effects by which the language of the despatch is signified. But the intensity of the current transmitted by a given voltaic battery upon a wire of given length will be increased in the same proportion as the area of the section of the wire is augmented.  Thus, if the diameter of the wire be doubled, the area of its section being increased in a fourfold proportion, the intensity of the current transmitted along the wire will be increased in the same ratio.  The intensity of the current may also be augmented by increasing the number of pairs of the generating plates or cylinders composing the galvanic battery.

All electrical terms are arbitrary, and necessarily unintelligible to the general reader.  I shall, therefore, use them as sparingly as possible, and endeavor to make myself clearly understood by explaining those which I do use.

All telegraphic conductors offer a certain resistance to the passage of an electric current, and the amount of this resistance is proportional to the length of the conductor, and inversely to its size.  In order to overcome this resistance, it is necessary to increase the number of the cells in the battery, and thus obtain a fluid of greater force or intensity.