No one is ignorant of the curious struggle which went on during the
Federal war between the projectile and ironclad vessels, the former
destined to pierce the latter, the latter determined not to be pierced.
Thence came a radical transformation in the navies of the two
continents. Cannon-balls and iron plates struggled for supremacy, the
former getting larger as the latter got thicker. Ships armed with
formidable guns went into the fire under shelter of their invulnerable
armour. The Merrimac, Monitor, ram Tennessee, and Wechhausen shot
enormous projectiles after having made themselves proof against the
projectiles of other ships. They did to others what they would not have
others do to them, an immoral principle upon which the whole art of war
is based.

Now Barbicane was a great caster of projectiles, and Nicholl was an
equally great forger of plate-armour. The one cast night and day at
Baltimore, the other forged day and night at Philadelphia. Each followed
an essentially different current of ideas.

As soon as Barbicane had invented a new projectile, Nicholl invented a
new plate armour. The president of the Gun Club passed his life in
piercing holes, the captain in preventing him doing it. Hence a constant
rivalry which even touched their persons. Nicholl appeared in
Barbicane's dreams as an impenetrable ironclad against which he split,
and Barbicane in Nicholl's dreams appeared like a projectile which
ripped him up.

Still, although they ran along two diverging lines, these _savants_
would have ended by meeting each other in spite of all the axioms in
geometry; but then it would have been on a duel field. Happily for these