 When it came to vowel forms , Keats incorporated a pattern of alternating historically " short " and " long " vowel sounds in his ode . In particular , line 18 ( " And purple @-@ stained mouth " ) has the historical pattern of " short " followed by " long " followed by " short " and followed by " long " . This alteration is continued in longer lines , including line 31 ( " Away ! away ! for I will fly to thee " ) which contains five pairs of <unk> . However , other lines , such as line 3 ( " Or emptied some dull <unk> to the drains " ) rely on a pattern of five " short " vowels followed by " long " and " short " vowel <unk> until they end with a " long " vowel . These are not the only combination patterns present , and there are patterns of two " short " vowels followed by a " long " vowel in other lines , including 12 , 22 , and 59 , which are repeated twice and then followed up with two sets of " short " and then " long " vowel pairs . This reliance on vowel sounds is not unique to this ode , but is common to Keats 's other 1819 odes and his Eve of St. Agnes . 
