The rapidity of fire of the large guns has been greatly increased of late years, and compared with the destructive effects inflicted by some of the guns they have superseded, notwithstanding that the changes were not brought about without encountering some opposition, the new guns are held to have justified their selection to the fullest. The experiments made in firing on old battleships have shown what the guns then considered sufficient could accomplish, and as the muzzle velocity and muzzle energy and the other scientific data could all be calculated to a nicety, and the effects on certain constructions of armour when struck by projectiles of certain shapes and weights could be estimated approximately and verified by actual experiment, it became really a question for the gun-makers whether they could produce a weapon which, at the range at which modern actions at sea are likely to be fought in the future, would be able to penetrate the heaviest armour which could be placed on a battleship of known displacement. This problem has exercised the artillerists of all nations with naval aspirations, particularly those of Great Britain, Germany, Italy and the United States, and of recent years Japan. Austria has usually been content to follow the lead of Germany in this respect, and the other powers, such as the South American States, China, and the smaller European States, have had to content themselves with the advice of the experts in the gun-manufacturing countries, except when political necessities and diplomatic pressure have regulated their choice for them, to the financial advantage of the vendors. Some of the most powerful warships afloat have been designed by private firms, notably those built at Barrow, or on the Tyne, or at Liverpool, for the South American States, the _Minas Geraes_ and her two sisters being conspicuous examples. These vessels have each twelve 12-inch guns, twenty-two 4.7 quick-firers, and eight 3-pounder quick-firers, and four torpedo tubes. Their displacement is 19,250 tons, their horse-power indicated 24,500, and their speed 21 knots. The other nations made up their minds that they must follow the lead that England had set, and have _Dreadnought_ ships as good as hers or better. The naval architects of the powers have since been engaged in a struggle to surpass each other and England in particular. The name-ship has been so much improved upon in recent designs that she is as inferior to the last of the super-_Dreadnought_ battleships as the displaced pre-_Dreadnoughts_ were to her.