Abstract: A battle-ship is a vessel cspable of taking its place in the main fighting line.I n the present day of largc srmoured cruisers, the line of demarcation between the battle-ship and the cruiser becomes hard to define, and no attempt will be made to do so.Formerly the battle-ship was a vessel heavily armed and protected, and of a moderate speed, whereas the cruiser was a fast vessel, of large coal capacity, lightly armed and protected.Nowadays, naval shipbuilding policy shows a tendency to combine all these qualities, namely, speed, endurance, armament and proteo tion, in one type of large armbured vessel, and the battleship and the cruiser are so rapidly approaching one another that there is no fear of being accused of encroaching on cruiser territory whilst discugs ing the pros and cons of the vital matters dealt with in this essay.Kothing will be said on thc subject of t h e soundnee3 of t h e policy of possessing one t-ype of armoured vessel in the future, but a ship will be dcalt with only on her merits as a battleship, as already defined, and her qualities its a cruiser, where speed is a sine p a non, will not be considered.The paper is divided into ,fpur parts, which, taken in the sequence mentioned below, will, it is hoped, clearly show the line of argument and the deductions thcrefrom.Purt I.--In which are separately discussed the values of speed and armament., both tactically and strategically.Part Z1.-In wliicli are compared t h e relative values of these two elements, both tactically and strategically, and in which an attempt VOL.LI.