Most people are aware of the curious struggle which arose during the Federal war between the guns and the armour of iron-plated ships. The result was the entire reconstruction of the navy of both the continents; as the one grew heavier, the other became thicker in proportion. The "Merrimac," the "Monitor," the "Tennessee," the "Weehawken" discharged enormous projectiles themselves, after having been armour-clad against the projectiles of others. In fact they did to others that which they would not they should do to them—that grand principle of immorality upon which rests the whole art of war. Now if Barbicane was a great founder of shot, Nicholl was a great forger of plates; the one cast night and day at Baltimore, the other forged day and night at Philadelphia. As soon as ever Barbicane invented a new shot, Nicholl invented a new plate, each followed a current of ideas essentially opposed to the other. Happily for these citizens, so useful to their country, a distance of from fifty to sixty miles separated them from one another, and they had never yet met. Which of these two inventors had the advantage over the other it was difficult to decide from the results obtained. By last accounts, however, it would seem that the armour-plate would in the end have to give way to the shot; nevertheless, there were competent judges who had their doubts on the point. At the last experiment the cylindro-conical projectiles of Barbicane stuck like so many pins in the Nicholl plates. On that day the Philadelphia iron-forger then believed himself victorious, and could not evince contempt enough for his rival; but when the other afterwards substituted for conical shot simple 600 lb. shells, at very moderate velocity, the captain was obliged to give in. In fact, these projectiles knocked his best metal plate to shivers. Matters were at this stage, and victory seemed to rest with the shot, when the war came to an end on the very day when Nicholl had completed a new armour-plate of wrought steel. It was a masterpiece of its kind, and bid defiance to all the projectiles in the world. The captain had it conveyed to the Polygon at Washington, challenging the President of the Gun Club to break it. Barbicane, peace having been declared, declined to try the experiment. Illustration: NICHOLL PUBLISHED A NUMBER OF LETTERS IN THE NEWSPAPERS. Nicholl, now furious, offered to expose his plate to the shock of any shot, solid, hollow, round, or conical. Refused by the president, who did not choose to compromise his last success. Nicholl, disgusted by this obstinacy, tried to tempt Barbicane by offering him every chance. He proposed to fix the plate within two hundred yards of the gun. Barbicane still obstinate in refusal. A hundred yards? Not even _seventy-five!_ "At fifty then!" roared the captain through the newspapers. "At twenty-five yards!! and I'll stand behind!!!"