In merely technical quality the supremacy of Virgil's art has never been disputed. The Latin hexameter, "the stateliest measure ever moulded by the lips of man," was brought by him to a perfection which made any further development impossible. Up to the last it kept taking in his hands new refinements of rhythm and movement which make the later books of the _Aeneid_ (the least successful part of the poem in general estimation) an even more fascinating study to the lovers of language than the more formally perfect work of the _Georgics,_ or the earlier books of the _Aeneid_ itself. A brilliant modern critic has noted this in words which deserve careful study. "The innovations are individually hardly perceptible, but taken together they alter the character of the hexameter line in a way more easily felt than described. Among the more definite changes we may note that there are more full stops in the middle of lines, there are more elisions, there is a larger proportion of short words, there are more words repeated, more assonances, and a freer use of the emphasis gained by the recurrence of verbs in the same or cognate tenses. Where passages thus characterised have come down to us still in the making, the effect is forced and fragmentary; where they succeed, they combine in a novel manner the rushing freedom of the old trochaics with the majesty which is the distinguishing feature of Virgil's style. The poet's last words suggest to us possibilities in the Latin tongue which no successor has been able to realise." In these later books likewise, the psychological interest and insight which keep perpetually growing throughout Virgil's work result in an almost unequalled power of expressing in exquisite language the half-tones and delicate shades of mental processes. The famous simile in the twelfth _Aeneid_-- _Ac velut in somnis oculos ubi languida pressit Nocte quies, nequiquam avidos extendere cursus Velle videmur, et in mediis conatibus aegri Succidimus, nec lingua valet, nec corpore notae Sufficiunt vires aut vox et verba sequuntur--_