years ago and how they refused to yield to them. “The difference between myself and the French marshals,” the Duke of Wellington is reported to have said, “was as when a man starts on a journey with a new harness. What if something gives way, as in war something is sure to go wrong? Shall you stop or go back for a workman? Not so; hitch up the break with a bit of rope, or whatever comes handy, and go on. That is what I did.” The succession of cause and effect which has produced the present ship-of-war will be traced in rapid outline, in order to leave as much room as may be for the description of the essential feature of the ship herself as she now exists. Two chief factors concur to a ship-of-war—motive power and fighting power. The displacement of sails by engines, and the progressive development of the latter, are features of the general progress of the century. The engines of a ship-of-war are differentiated from those of merchant ships chiefly by the necessity of protection. This affects their design, which must be subordinated to the requirement of being as far as possible below the water-line. The further great protection now afforded is incident rather to the use and development of armor as a part of the fighting power. Fighting power divides into offensive and defensive. Armor now represents the latter. The fighting ship in every age is the product of the race between the two, and in the nineteenth century this was unprecedented in the ground covered and in the rapidity of the pace, due to the increased power of dealing with materials, already alluded to. CONTEST OF ARMOR AND PROJECTILE