When, after such verses, we find one in which the author expresses a single idea so happily, as just to fill up the _quatrain_, the difference is immediately visible, betwixt a simile easily and naturally introduced, and stanzas made up and levelled with what a poet of those times would perhaps have ventured to call the _travelled earth_ of versification: And now four days the sun had seen our woes; Four nights the moon beheld the incessant fire; It seemed as if the stars more sickly rose, And farther from the feverish north retire. Of all these difficulties our author seems to have been aware, from his preliminary epistle to Sir Robert Howard; and it was probably the experimental conviction, that they were occasionally invincible, which induced him thenceforward to desert the _quatrain_; although he has decided that stanza to be more noble, and of greater dignity, both for the sound and number, than any other verse in use among us. The turn of composition, as well as the structure of the verse, is adopted from "Gondibert." But Dryden, more completely master of the English language, and a writer of much more lively imagination and expression, has, in general, greatly exceeded his master in conceiving and bringing out the far-fetched ideas and images, with which each has graced his poem. D'Avenant is often harsh and turgid, and the construction of his sentences extremely involved. Dryden has his obscure, and even unintelligible, passages; but they arise from the extravagance of the idea, not from the want of power to express it. For example, D'Avenant says, Near her seems crucified that lucky thief, In heaven's dark lottery prosperous more than wise, Who groped at last by chance for heaven's relief, And throngs undoes with hopes by one drawn prize. We here perfectly understand the author's meaning, through his lumbering and unpoetical expression; but, in the following stanza, Dryden is unintelligible, because he had conceived an idea approaching to nonsense, while the words themselves are both poetical and expressive: Then we upon our globe's last verge shall go, And view the ocean leaning on the sky; From thence our rolling neighbours we shall know, And on the lunar world securely pry. In short, Dryden never fails in the power of elegant expression, till he ventures upon something which it is impossible to express.