Some six months before the _Captain_ was lost a ship was launched which introduced another and most successful type, yet she was rather an improvement on certain earlier vessels than an entirely modern conception. This was the _Devastation_, and she was at once recognised as the most powerful ship of war in the world. The _Glatton_, a single turret ship, launched in 1869, may in some respects be regarded as the forerunner of the _Devastation_. The _Glatton_ was a low freeboard coast-defence monitor, modified to suit the conditions prevailing on the English side of the Channel; but the _Devastation_, while still being of comparatively low freeboard, was a sea-going ship, mastless, so far as sails were concerned, and double turreted. The _Devastation_ was the historical reply of the British naval constructors to the much-vaunted American monitors, and also the Admiralty’s reply to the _Captain_. She was so unlike anything else afloat, that the writers of those days had difficulty in finding anything to which they could compare her. One describes her as like an “impregnable piece of Vauban fortification with bastions mounted upon a fighting coal mine.” As a mastless turret ship or fighting machine, she possessed powers of offence, defence, and manœuvring greater than those of any other ship in the world. This ship, which was built at Portsmouth, and the _Thunderer_, built at Pembroke, were the pioneers of this class of vessel, and were the first to embody in their construction the most perfect examples of the turret principle as at that time understood, applied to a sea-going ship.[42] They were superior to any others built or building as fighting machines, and in their coal-carrying capacity. They were of 4,406 tons burden under the old system of measurement. They were given 12 inches of rolled armour plating on a teak backing built into an immensely strong framing, 18 inches in thickness, which was further backed with an iron skin 1½ inches thick. There was not only the increased thickness of the armour, but also its quality to be taken into consideration in comparing these vessels with the _Warrior_ and _Minotaur_, for the resistance offered by the rolled armour of the new ships increased very nearly as the square of the thickness, so that the sides of the _Devastation_ and the _Thunderer_ were, all things considered, about seven times as strong as those of the _Warrior_. The thickest armour carried in the French navy was that of the peculiar rams of the “_Taureau_” or “_Bélier_” type, mentioned on another page, viz. 8¼ inches, while that of the American monitors was 6 inches of plating on a system of armour stringers. The two English ships by reason of their higher freeboard were better sea-boats than any monitors built on the American principle could ever hope to be. The American turrets leaked badly whenever it was necessary to place their weight on the spindles to enable them to revolve, and