Of all the factors influencing the evolution of naval material, the experiences and records of actual warfare are naturally considered to carry the greatest weight in council: they are, indeed, the only data whose acceptance is indisputable. The claims and achievements put forward in time of peace, however their excellence may have been attested by the most realistic experiments, are all referred to actual war for trial, and are accepted only in so far as they fit in with war experience. But sea actions between ironclads have been few and far between. It has been the more difficult, therefore, to draw from them the true lessons conveyed; the fixed points have been insufficient in number, so to speak, to allow of the true curve of progress being traced. Not only has this insufficiency been evident, but the restriction in the area of war experience has had another harmful effect, in that undue weight has been given to each individual experience. Difficult as it always is to strip each experience of its special circumstances and deduce from it the correct conclusion, errors have undoubtedly been made; and these errors have had a prominence which would not have been theirs if the number of experiences had been greater. On the other hand, an altogether insufficient weight has commonly been given to the experiences of peace-time. These remarks find one application in the ram, and in the value placed upon it in the ’sixties and ’seventies. During this period artillery was undergoing a continuous and rapid improvement, eventually turning the scales against defensive armour; steam power was expanding and the manœuvring capacities of ships were being extended, so as to make ramming an operation more and more difficult to perform. Yet faith in the ram grew rather than decreased, influenced almost entirely by the evidence of the two sea-actions.