For when the rich original we peruse, And by it try the metal you produce, Though there indeed the purest ore we find, Yet still by you it something is refined; Thus when the great Lucretius gives a loose And lashes to her speed his fiery Muse, Still with him you maintain an equal pace, And bear full stretch upon him all the race; But when in rugged way we find him rein His verse, and not so smooth a stroke maintain, There the advantage he receives is found, By you taught temper, and to choose his ground.[409] So authoritative a critic as Roscommon, however, seems to oppose attempts at improvement when he writes, Your author always will the best advise, Fall when he falls, and when he rises, rise, a precept which Tytler, writing at the end of the next century, considers the one doubtful rule in _The Essay on Translated Verse_. "Far from adopting the former part of this maxim," he declares, "I consider it to be the duty of a poetical translator, never to suffer his original to fall. He must maintain with him a perpetual contest of genius; he must attend him in his highest flights, and soar, if he can, beyond him: and when he perceives, at any time a diminution of his powers, when he sees a drooping wing, he must raise him on his own pinions."[410] The influence of Denham and Cowley is also seen in what is perhaps the most significant element in the seventeenth-century theory of translation. These men advocated freedom in translation, not because such freedom would give the translator a greater opportunity to display his own powers, but because it would enable him to reproduce more truly the spirit of the original. A good translator must, first of all, know his author intimately. Where Denham's expressions are fuller than Virgil's, they are, he says, "but the impressions which the often reading of him hath left upon my thoughts." Possessing this intimate acquaintance, the English writer must try to think and write as if he were identified with his author. Dryden, who, in spite of his general principles, sometimes practised something uncommonly like imitation, says in the preface to _Sylvae_: "I must acknowledge that I have many times exceeded my commission; for I have both added and omitted, and even sometimes very boldly made such expositions of my authors as no Dutch commentator will forgive me.... Where I have enlarged them, I desire the false critics would not always think that those thoughts are wholly mine, but either that they are secretly in the poet, or may be fairly deduced from him; or at least, if both these considerations should fail, that my own is of a piece with his, and that if he were living, and an Englishman, they are such as he would probably have written."[411]