As in the restoration of sounder methods, with which we shall be concerned, this degeneration of ideals was a work of time. In June, 1666, the British met with a severe check in the Four Days Battle, in which Monk, a soldier, commanded in chief. This reverse is chiefly to be attributed to antecedent strategic errors, which made a portion only of the available British force bear the brunt of the first three days; but, among the inevitable criticisms, we find stress laid upon fighting in line as essential to success. This insistence upon the line as an effective instrument proceeded, among others, from Sir William Penn, a seaman, and was at that time in the direction of professional advance. The line had not yet obtained the general professional acceptance needed to establish and utilize its indisputable value. This process was gradual, but when effected it followed the usual laws of human development; from a valuable means, it became in men’s estimation an exaggerated necessity. It came to pass in time that the line no longer existed for tactics, but tactics for the line, in which they found their consummation and end.
There intervened, however, a happier period,—one of transition,—and in the third Anglo-Dutch war, 1672-1674, we seem to find a close approach to just proportion between regularity of formation and decisive tactical purpose; in which the principle of the line is recognized and observed, but is utilized by professional audacity for definite and efficient tactical action, aiming at conclusive results. The finest exponent of this, the culminating epoch of naval warfare in the seventeenth century, is the Dutchman Ruyter, who, taken altogether, was the greatest naval seaman of that era, which may be roughly identified with the reign of Charles ii. After that, naval warfare was virtually suspended for fifteen years, and when resumed in the last decade of the century, the traces of incipient degeneracy can already be noted amid much brilliant performance. From that time completeness of military achievement became in men’s minds less of an object than accurate observance of rule, and in practice the defensive consideration of avoiding disaster began to preponderate over offensive effort for the destruction of the enemy.