The most striking feature of the metrics of the poem is its use of hypermetric lines. Lines 8 - 10; 20 - 23; 30 - 34; 39; 40b - 43; 46 - 49; 59 - 70 are all hypermetric. 75 has also been printed and scanned as a hypermetric but the fact that the text is clearly corrupt at this point makes it uncertain. 39a and 40a are not clearly hypermetric. 133 would also seem to me to be a hypermetric line (its scansion is otherwise difficult). Bliss does not appear to accept this one. 9 does not scan even as a hyprmetric line. The metrical difficulty supports the case for emendation of this line.
As the numbers above show, the hypermetric lines occur in irregular blocks of 3, 4, 5, 5, 4, 9 lines together at irregular intervals in the first half of the poem. Hypermetric lines are so called because they appear to have 3 stresses (or equivalents) in each of the verses rather than the normalæ 2. The Dream of the Rood is not the only poem to vary its metre in this way. Judith shows a similar arrangement of irregular blocks of lines and occasional lines or groups of lines ocur in a number of other poems. Bliss, The Metre of Beowulf p.162-8 lists all the hypermetric verses he considers to exist in Old English poetry with their proposed scansion.
As a literary and textual feature these lines present a problem. The rules which govern their scansion are even less clear than those which govern normal verses. It is not clear, either, what effect they were intended to have or what artistic conventions governed their introduction. Suggestions have been made that their effect is to slow up the verse, to produce a more solemn tone, perhaps. They obviously have the effect of breaking the possible monotony of the same repeated verse patterning but, if variation is what they provide, it is curious that they do not occur more frequently in the longer poems.
Extracts taken from Ann Squires essay "The Metre of the Poem"
June 1994