One result of the victory won by Tegethoff at Lissa was that an exaggerated importance was for many years to come attached to the ram as a weapon of attack. In every navy in the world ships were built with bows specially designed for ramming. The sinking of the "Re d'Italia" had made such an impression on the public mind, that it was in vain for a minority among naval critics to urge that the ram was being overrated, and to point out that even at Lissa for one successful attempt to sink an enemy by running her down there had been an untold number of failures. It was very gradually that the majority was brought to realize that a ship under full control could generally avoid a ramming attack, and that it could only be employed under exceptional circumstances, and against an already disabled enemy. Then the progress of invention and armaments introduced features into naval warfare that made it extremely difficult and dangerous for a large ship to come to such close quarters as an attempt to ram implies. First the introduction of the Whitehead torpedo as part of the auxiliary armament of battleships and cruisers gave the ship attacked a means of sinking the aggressor as she approached, and the increase in the power of guns led naval tacticians to accept as a principle that fleet actions must be fought at ranges which were regarded as too distant for any effective action in earlier days. But for nearly thirty years after Lissa there were no fleet actions. Ships, armour, guns, were all improved, and the great naval Powers built on a larger and larger scale. Steel took the place of iron as the material for shipbuilding and armour. Naval gunnery became a precise science. Torpedoes were introduced, and with them such new types of ships as the swift torpedo boat and the "destroyer." But there was very little fighting on the sea, though in the same period there were colossal conflicts on land. Hundreds of armour-clads were built that became obsolete, and were turned over to the shipbreaker, without ever having fired a shot in action. Theories of tactics for fleet actions were worked out on paper, and tested to some extent at naval manoeuvres, but the supreme test of battle was wanting. In the Franco-German War of 1870 the French navy had such a decided superiority that the few German warships of the day were kept in their harbours protected by batteries and sunken mines. The only naval action of the war was an indecisive duel between two gunboats. In the second stage of the war the officers and men of the French navy fought as soldiers in the defence of France. Guns were taken from the ships to be mounted on land fortifications. Admirals commanded divisions, formed largely of naval officers and bluejackets.