Over the course of his career, Mr. Hearn wrote for many newspapers and magazines. Here is a short list off the top of my head (later to be edited... now edited and thus no longer "off the top of my head") of these papers, journals, and magazines:
Boston Investigator (1869?)
Cincinnati Trade List - Proofreader (187?)
Cincinnati Inquirer - Journalist (1872)
Cincinnati Commercial - Journalist (1875)
New Orleans Daily City Item - Assistant Editor (1878)
New Orleans Times-Democrat - Literature and Translation (1881)
San Francisco Argonaut - Contributor (1882)
Century Magazine - Contributor (1883)
Harper's Weekly - Contributor (1883)
Harper's Bazaar - Contributor (1885)
New York Tribune - Contributor (1886)
Southern Bivouac - Contributor (1886)
Atlantic Monthly - Contributor (????)
Cosmopolitan - Contributor (1890)
Harper's Magazine - Contributor (1890)
Kobe Chronicle - Journalist (1895)
McClure Syndicate - Contributor (1895)
more to come...