In 1837, Margaret Prior became the first female missionary for the American Female Moral Reform Society. She traveled throughout the poorest neighborhoods in New York City--entering barrooms, brothels, and sickrooms. Based on an analysis of Prior's missionary reports, published in the society's periodical and included in her memoir, this essay shows how Prior exerted an ethos of presence. Her willingness to traverse the seediest sections of the city, call on any person, and address any need exerted a powerful ethos in the communities she served and among the audiences who read and heard about her efforts. (Contains 3 notes.)