What two things is Homer comparing in the following epic simile? "Joy, warm as the joy that shipwrecked sailors feel when they catch sight of land—Poseidon has struck their well-rigged ship on the open sea with gale winds and crushing walls of waves, and only a few escape, swimming, struggling out of the frothing surf to reach the shore, their bodies crusted with salt but buoyed up with joy as they plant their feet on solid ground again—so joyous now to her the sight of her husband, vivid in her gaze that her white arms, embracing his neck would never for a moment let him go."