Many of these stock epithets owed their appearance of course to the requirements imposed upon poets by their adherence to the heroic couplet. Pope himself calls attention to the fact that the necessities of rhyme led to the unceasing repetition of stereotyped phrases and locutions: Where’er you find the “cooling western breeze.” In the next line it “whispers through the trees”; If crystal streams “with pleasing murmur creep” The reader’s threaten’d, not in vain, with “sleep”— adducing, with unconscious irony, the very rhymes prevalent in much of his own practice.[61] It was also recognized by the versifiers that the indispensable polish and “correctness” of the decasyllabic line could only be secured by a mechanical use of epithets in certain positions. “There is a vast beauty [to me],” wrote Shenstone, “in using a word of a particular nature in the 8th and 9th syllable of an English verse. I mean what is virtually a dactyl. For instance, And pykes, the tyrants of the wat’ry plains. Let any person of any ear substitute _liquid_ for _wat’ry_ and he will find the disadvantage.”[62] Saintsbury has pointed out[63] that the “drastic but dangerous device of securing the undulating penetration of the line by the use of the _gradus_ epithet was one of the chief causes of the intensely artificial character of the versification and its attendant diction.... There are passages in the ‘Dispensary’ and ‘The Rape of the Lock,’ where you can convert the decasyllable into the octosyllable for several lines together without detriment to sense or poetry by simply taking out these specious superfluities.”