This is Merlin's first moment of weakness, where he has "half believed her true" ("Merlin and Vivien" 398)-as the effects of her song soften his heart, her power over him slowly gathers. As her influence subtly grows, so his power is slowly pulled away from him, much like nearly the imperceptible pull of waters away from the shore before a wave breaks. Having gathered her strength, she then speaks "breaking in upon him" ("Merlin and Vivien" 598). Her flattery and flirtation strike the next great blow against Merlin, causing him to behave as if he is of the "school where blind and naked Ignorance Delivers brawling judgments, unashamed, On all things all day long " ("Merlin and Vivien" 662-664). This active use of persuasion successfully shakes Merlin, allowing Vivien to sweep crucial information about the charm from him. Then, in her final moments of persuasion, she speaks with her voice "broken with sobs" ("Merlin and Vivien" 855). The wave of Vivien's power has fully crashed upon the shore, dousing Merlin's solid earth-his resistance-with the water of her tears. Her tears, long foreshadowed by the water imagery, are the decisive force that ultimately breaks down his resistance just as water breaks rock into sand, allowing her to wash his "use and name and fame" out to sea. .
In choosing to use the image of a crashing wave to illustrate Vivien's persuasion, Tennyson comments on the nature of power. Notably, Vivien is not the only one described as a wave-when Vivien first reveals herself to Merlin in the forest, Merlin's thoughts are described as being like "on a dull day in an Ocean cave The blind wave feeling round his long sea-hall In silence" ("Merlin and Vivien" 229-231). In this state, Merlin's power is sorely limited. He is unable to crash against the shore to influence the world about him; rather, he merely feels his way about, trapped and impotent.
