Dryden was the first great English poet after Chaucer to make the heroic couplet his chief vehicle of expression, and he put far more variety and vigor into it than had been achieved by his nearer predecessors. As Pope said: "Waller was smooth, but Dryden taught to join The varying verse, the full resounding line, The long majestic march, the energy divine." (_Epistle ii._, 267.) And Gray, some years later, symbolized Dryden's couplet in these fine lines of the _Progress of Poesy_: "Behold, where Dryden's less presumptuous car, Wide o'er the fields of glory bear Two coursers of ethereal race, With necks in thunder clothed, and long-resounding pace." On Dryden's development of the couplet, see especially Saintsbury's _Life of Dryden_ (English Men of Letters Series), pp. 17, 171. "The whole structure of the decasyllabic line before the middle of the seventeenth century was ill calculated for the perfecting of the couplet. Accustomed either to the stately plainness of blank verse, or to the elaborate intricacies of the stanza, writers had got into the habit of communicating to their verse a slow and somewhat languid movement." (p. 17.) "In versification the great achievement of Dryden was the alteration of what may be called the balance of the line, causing it to run more quickly, and to strike its rhymes with a sharper and less prolonged sound. One obvious means of obtaining this was, as a matter of course, the isolation of the couplet, and the avoidance of overlapping the different lines one upon the other. The effect of this overlapping, by depriving the eye and voice of the expectation of rest at the end of each couplet, is always one of two things. Either the lines are converted into a sort of rhythmic prose, made musical by the rhymes rather than divided by them, or else a considerable pause is invited at the end of each, or of most lines, and the cadence of the whole becomes comparatively slow and languid. Both these forms, as may be seen in the works of Mr. Morris, as well as in the older writers, are excellently suited for narration of some considerable length. They are less well suited for satire, for argument, and for the moral reflections which the age of Dryden loved. He therefore set himself to elaborate the couplet with its sharp point, its quick delivery, and the pistol-like detonation of its rhyme. But there is an obvious objection, or rather there are several obvious objections which present themselves to the couplet. It was natural that to one accustomed to the more varied range of the older rhythm and metre, there might seem to be a danger of the snip-snap monotony into which, as we know, it did actually fall when it passed out of the hands of its first great practitioners. There might also be a fear that it would not always be possible to compress the sense of a complete clause within the narrow limits of twenty syllables. To meet these difficulties Dryden resorted to three mechanical