Noted: The essay, a roughly 500-word sermonlike meditation called “Individual Influence,” was found at the New York Public Library by Jonathan Senchyne, an assistant professor of book history at the University of Wisconsin. The document, which will be published in October in PMLA — the journal of the Modern Language Association — appears to be the first prose essay in Horton’s handwriting to come to light, and one of only a handful of manuscripts in his own handwriting known to survive.