In one poem, this author described the souls of two lovers enduring "not yet a breach, but an expansion, like gold to airy thinness beat." In another poem by this author, a pair of lovers are "cloistered in these living walls of jet." The lines "Thy firmness makes my circle just, and makes me end where I begin" conclude this poet's analogy of a pair of lovers to the feet of a compass. This poet asked: "hast thou since purpled thy nail?" in a poem describing a creature that "sucked me first, and now sucks thee," and contains the speaker and his lover's "mingled blood." 
In one poem, this author described the souls of two lovers enduring "not yet a breach, but an expansion, like gold to airy thinness beat." In another poem by this author, a pair of lovers are "cloistered in these living walls of jet." The lines "Thy firmness makes my circle just, and makes me end where I begin" conclude this poet's analogy of a pair of lovers to the feet of a compass. This poet asked: "hast thou since purpled thy nail?" in a poem describing a creature that "sucked me first, and now sucks thee," and contains the speaker and his lover's "mingled blood." For 10 points, name this metaphysical poet who wrote "A Valediction: Forbidding Mourning" and "The Flea."
In one poem, this author described the souls of two lovers enduring "not yet a breach, but an expansion, like gold to airy thinness beat."