The second problem was how to carry more powerful guns afloat, and how to strengthen the sides of the hulls supporting them so as to offer adequate resistance to the projectiles of equally heavy guns carried by hostile ships or discharged from the enemy’s forts. The first problem was found to be comparatively easy, notwithstanding that the solution when proposed was declared by many to be impossible. It had, moreover, an important influence upon the attempted solution of the second problem. The latter was even thought to be no more difficult than the other, but the effort to grapple with it marked the beginning of the great struggle between guns and armour, and the introduction of the question of long range as against short range fighting, the end whereof is not yet. Some little time before the war, the Emperor of the French expressed the opinion that armoured vessels of the types the Americans had devised, notably Stevens’s and Ericsson’s ships, were more suitable for purposes of war than the large two-deckers and three-deckers. He was confirmed in this opinion by the experiences of the big ships in the attack upon Fort Constantine, and though the opposition to his views was great, and it was pointed out that the forts must ultimately be starved into surrendering, he maintained that this would take too long and that the forts must be attacked by other means. His Majesty himself, who had devoted considerable attention to the subject, was largely responsible for the design of the five armoured French gunboats which were destined to bring about the abandonment of the great three-deckers and initiate as remarkable a revolution in warship construction as the introduction of steam was causing in naval tactics. These floating batteries--a term borrowed from the Americans--were the _Lave_, _Tonnante_, _Congreve_, _Foudroyant_ and _Dévastation_. Their dimensions were similar: 1,400 tons displacement, 164 feet in length, 42 feet 6 inches beam, and drawing only 8 feet of water. They were built with massive wooden frames, to which were attached oaken sides 8 inches in thickness, and outside this was iron plating 4⅜ inches thick. The _Tonnante_, launched at Brest in March, 1855, was the first afloat--the first iron-clad citadel ship built in Europe. After the Emperor had decided on the plans and the vessels were in course of construction, Ericsson communicated with his Majesty on the subject. He was not aware that the Emperor had already determined on the plans of the ironclads, or he would scarcely have gone to the trouble of writing, for his experience of European governments was not such as to lead him to think that they would admit he was able to teach them anything. He is variously said to have offered to design a turret ship for the Emperor, and to have presented to the Emperor plans of a partially submerged armoured vessel with guns in a revolving shot-proof cupola placed centrally on the deck. In either case, however, he was too late.