In all our great naval wars, our ships had only a single weapon, the gun, and this not a very heavy one, for the highest limit of naval ordnance was the sixty-eight pounder, which indeed was looked upon as a very terrible weapon. To the guns of nowadays, the old thirty-two and sixty-eight pounders are mere pop-guns. There is the huge eighty-one-ton gun, twenty-four feet long, and six feet thick at the breech, its huge shot of fifteen hundred pounds being capable of penetrating thirty inches of armour. There is the thirty-eight-ton gun, whose shot of six or seven hundred pounds weight has smashed a thirteen-inch plate at a thousand yards. Then there are guns of six-and-a-half, nine, twelve, eighteen, and twenty-five tons, with projectiles weighing from one to six hundred pounds, all of them capable of piercing armour, against which the old naval guns would be as useless as a schoolboy's squirt. But the gun does not stand alone. There are two other weapons, either of which is more terrible, and in certain cases more effective than the heaviest gun afloat. These are the ram and the torpedo, the latter of which has recently been described in these columns. Let us, however, have a look at the ram. In the old days, the ship herself had no attacking power. She fought with her guns; or else she was laid alongside of her enemy, and the crew with axe, pike, and cutlass clambered over the bulwarks and on to the hostile decks, which they cleared by hand-to-hand fighting. Probably no iron-clad will ever be laid alongside of another to board her. Were an iron-clad to go into action, all the openings in the deck would be closed, and every one, even the steersman, under cover. Many modern ships could continue a fight successfully with a hundred or a hundred and fifty boarders in possession of the upper deck; and their own turret guns, or the fire of friendly ships, would clear away the intruders if necessary. Thus, in the recent war between Paraguay and Brazil, during one of the river engagements, a Paraguayan ship ran alongside of a Brazilian turret-ship and sent a crowd of boarders on to her iron decks. They met with no opposition; the round turret in front of them continued its fire against a Paraguayan monitor; while another Brazilian monitor sent volley after volley of grape-shot sweeping across the decks of her consort. In a few minutes they were clear. The Paraguayan boarders had been killed, had jumped into the water, or had escaped to one of their own ships. This, we believe, is the only attempt on record at boarding an iron-clad; its failure shews how hopeless such an enterprise is against a ship the possession of whose deck does not give any control over her movements or those of her crew. It is therefore probable that it will be only in the most exceptional cases that iron-clads will approach each other with the object of boarding. If they do come to close quarters, it will be only to use the ram.