The running fight which followed the sortie of the Russian fleet at Port Arthur, and the decisive battle of Tsushima Straits, crystallized into fact many theories of the design and maneuvering of warships; and settled, probably for many years to come, the vexed questions of the size of ship, the type of gun, and the best formation in which to fight a naval action. The battleship of the future will be of great size; displacement will be not less than 20,000 tons; and this will increase so rapidly that a 30,000-ton ship will probably be afloat before the close of the next decade. The main armament will consist exclusively of heavy guns of not less than 12 inches caliber; and, unless the difficulty of erosion can be overcome, the 12- inch will give place to a 13-inch and, possibly, to a 14-inch piece. Future engagements will be fought at an extreme range, the extent of which will be limited only by the ability of the fire-control officer to see the fall of the shots. The determination of the range at which an engagement shall be fought will lie with the fleet which possesses the fastest speed. It is to-day the almost unanimous opinion of naval officers that one big ship is more effective than two smaller ships of half her size. Future engagements will be fought with the two fleets steaming in parallel lines, in what is known as line ahead formation; that is, with each ship of a fleet steaming in the wake of the one ahead, with an interval of about 500 yards between them. If, of two such fleets, one were made up of four 20,000-ton battleships, each carrying eight 12- inch guns, the whole line would be about 2,100 yards in length; and if the other fleet consisted of eight 10,000-ton ships, each mounting four 12-inch guns, the line would be 5,600 yards in length, or over three miles. The fleet of larger ships would probably have sufficient advantage in speed for the admiral to maintain his four vessels abreast of the first four of the enemy's line; and, in this case, an eight-gun ship would be opposed to a four-gun ship, with the inevitable result (if the gunners were at all equally matched) that the four smaller ships would be silenced. The fleet of larger vessels would then slacken speed and drop back, taking the ships of the enemy in turn, and smothering them with a superior gun fire. At the opening of such an engagement the fifth and sixth in line of the four-gun ships would be able to direct a diagonal fire upon the last of the eight-gun ships, but the range would be so great that it could not prove to be very effectual. Unquestionably, the victory in future engagements will lie with the fleet which is able to concentrate the largest number of heavy guns within the shortest line of battle. Hence, the raison. d'etre of the big ship; and, hence the certainty that the navies of the world have been forced into a contest of size, the end of which no one can foretell. The enormously destructive power of the big gun at close ranges; the unwillingness of an admiral to expose his costly ships to the swift destruction which a close-range engagement would involve; and his natural desire to utilize the skill of his gunners to the utmost by forcing the supposedly less skillful enemy to fight at the greater ranges, are responsible for the fact that in the Japanese war the range was about 5,000 yards, and in future wars will probably be 7,000 and over. But at long ranges it is only the larger guns that can do effective work against an armored ship; and it has come to be pretty generally conceded that for this purpose the 12-inch piece is the most satisfactory. It is true that the 50-caliber, 9.2-inch gun, and long-caliber pieces of 10-inch and 11-inch caliber, are also armor-piercers at this range; but it takes the 12-inch gun to get through belt, barbette, and turret armor, and the destructive effect of the heavier projectiles is enormously greater. Furthermore, the flatter trajectory, or curve of flight, of the larger gun means a much wider danger space; that is to say, the 12-inch piece can hit a ship with a much wider margin of error in elevation than a 9.2-inch or 10-inch gun; and, although the smaller gun will deliver more projectiles, it is now generally conceded that the greater destructive effects and the greater certainty of hitting of the 12-inch overbalances the advantages of greater rapidity of fire of the lighter guns. Now, although the above considerations will lead to the elimination from the main batteries of future battleships of mixed batteries of 6-inch, 7-inch, 8-inch, and 12-inch guns, such as are mounted on the “Georgia” and the “Connecticut,” there is another and most important consideration which will lead to the mounting of only one caliber of gun on future ships, and that is the question of “fire control.” The latest method of obtaining the range and of directing the fire is not dependent, as is popularly supposed, upon the range flnder. Because of the narrow base line afforded by even the largest ships, it is impossible to estimate distances, at the great ranges which are now used, with any accuracy, by even the best form of range finder. The method now adopted is to have a “fire- control station” in some lofty position on the ship, and find the range by trial shots. The observing officer notes the splash of the shell and telephones the result to the gun, and the elevation is changed until a hit is made. Now, when three or four calibers of guns are firing indiscriminately, it becomes difficult to distinguish the splash of one caliber of shell from that of another. With one type of gun on the ship, there can be no error of this kind, and the fire can be directed with great accuracy. As to the size of the future gun, there are indications that it will steadily increase. Already, Great Britain is, we understand, manufacturing a new and extremely powerful 131h-inch piece for her new twelve- gun ships. The advantage of size is not only that the bigger gun is more accurate, but that it holds its velocity longer, and its striking energy is therefore proportionately greater at the longer ranges. Increase in caliber, however, means a great increase in weight; and, were it not for erosion, our ordnance officers would prefer to obtain increased accuracy and striking energy by an increase of velocity. By using the wire-wound system and increasing the powder charge, it wodd be possible to produce a 12-inch gun which would be even more accurate than a 131h-inch of the ordinary model, and would strike a blow of equal energy. But the increased erosion in such a gun would render its life very short—a defect which might have disastrous consequences in a long-drawn-out naval campaign.