The hammer is surrounded with four furnaces heated by gas, and duty is done for each of these by steam cranes capable of lifting 350,000 pounds. These cranes take the glowing block from the furnace, place it upon the anvil, and turn it over on every side at the will of the foreman. Under this hammer a cannon is forged as if it were a mere bolt. The piece is merely rough-shaped upon the anvil, and a metallic car running upon a 36 foot track carries it to the adjusting shop. There the cannon is turned, bored, and rifled, and nothing remains but to temper it, that is to say, to plunge it into a bath after it has been heated white hot. For this purpose an enormous ditch has been dug in which there is a cylindrical furnace, and alongside of it there is a well of oil. The car brings the cannon to the edge of the ditch, and a steam crane performs the operation of tempering with as much ease as we would temper a knife blade. In the presence of such engines of attack it was necessary to think of defense. The hammer that forges the cannon also gives us the armor plate to brave it. This time the ingot is flattened under the blows of the hammer, and even takes the rounded form of the stern, if it be so desired. Thus is obtained the wall of steel that we wish. Will it be possible to keep up the fight long? In order that one may get some idea of this for himself, let us rapidly describe an entirely peaceful contest that took place recently upon the coast of Italy. Two rival plates, one of them English and the other French, were placed in the presence of the Spezia gun, which weighs 100 tons. These plates were strongly braced with planks and old armor plate. Three shots were to be fired at each of the plates. In the first shot the ball was of hardened cast iron, and weighed 1,990 pounds. The English plate was filled with fissures, while the Creusot did not show a single one. The ball penetrated it about seven inches, and was broken into small pieces. In the second shot the projectile was the same, but the charge was greater. The shot may be calculated from the velocity, which was 1,530 feet. It was equal to what the great hammer would give were it to fall from a height of a hundred yards. The English plate was completely shivered, while the French exhibited but six very fine fissures radiating from the point struck. The ball entered 8 inches, and was broken as in the first experiment. The third shot fired was with a steel ball, against the French plate, the English being _hors de combat_. The penetration was the same; the ball was not broken, but was flattened at the point like the head of a bolt.