The Cambridge History of English and American Literature in 18 Volumes (1907–21). Volume XI. The Period of the French Revolution. XI. The Prosody of the Eighteenth Century. § 2. The Octosyllabic Couplet. The heroic couplet of Dryden, already sufficiently discussed, underwent, in the earliest years after Dryden’s death, changes which, considering the natural tendencies of humanity, may be called inevitable. By his own almost inimitable combination of skill and strength, and by the mechanical devices of triplet and Alexandrine, Dryden himself had kept off the monotony which the regular stopped couplet invites. But the invitation was sure to be accepted by others; indeed, they might plead that they were only realising the ideal of the form. As Waller and others before Dryden, wittingly or unwittingly, had hit upon the other devices of sententious balance and a split in the individual lines, and of pendulum repetition in the couplets: so, after Dryden, first Garth and then Pope, no doubt with their eyes open, rediscovered these; and the extraordinary craftsmanship of Pope carried the form to its highest possible perfection. If—and it is difficult to see how the assertion can be denied—the doctrine expressed in various ways but best formulated by De Quincey that “nothing can go wrong by conforming to its own ideal’ be true, the couplet of Pope, in and by itself, is invulnerable and imperishable.   3   But it very soon appeared that a third adjective of the same class, which indicates almost a necessary quality of the highest poetic forms, could not be applied to it. It was not inimitable. The admitted difficulty, if not impossibility, of deciding, on internal evidence, as to the authorship of the books of The Odyssey translated by Pope himself, as compared with those done by Fenton and Broome, showed the danger; and the work of the rest of the century emphasised it. Men like Savage, Churchill and Cowper went back to Dryden, or tried a blend of Dryden and Pope; men like Johnson and Goldsmith newminted the Popian couplet, in the one case by massive strength, in the other by easy grace of thought and phrase and form. But the dangers of monotony and of convention remained; and, towards the end of the period, they were fatally illustrated in the dull insignificance of Hoole and the glittering frigidity of Darwin.   4   From one point of view, it is not fanciful or illogical to regard all other serious, and most other light, measures of this time as escapes from, or covert rebellions against, this supremacy of a single form of heroic; but, as has been pointed out above, one metre stands in somewhat different case. The octosyllabic couplet had been little practised by Dryden, though, when he tried it, he showed his usual mastery; and it evidently did not much appeal to Pope. But Butler had established it with such authority that, till well into the nineteenth century, it was called specifically “Hudibrastic”; and two of the greatest verse writers of the early eighteenth, Swift and Prior, had used it very largely and very successfully, so that it could not be regarded as in any way insignificant, old-fashioned, or contraband. It was, in fact, as much the recognised metre of the century for light or brief narrative and miscellaneous purposes not strictly lyrical, as the heroic was for graver and larger work. But, as Dyer showed early and others later, it served—owing to the earlier practice of Milton more especially—as a not ineffectual door for smuggling in variations of line-length and foot-arrangement which were contraband, but of very great value and efficacy.   5