Othmeralia is an engrossing Tumblr blog that highlights archival materials from the Othmer Library of Chemical History, part of the Chemical Heritage Foundation in Philadelphia. Since 1988, the Othmer Library has collected a variety of materials related to the history of chemistry, and is now home to over 140,000 rare books, photographs, oral histories, manuscripts, and other archival material. Othmeralia showcases these hidden treasures for members of the general public to enjoym while also highlighting archives of interest from other libraries. Updated almost daily, recent posts of note include an 1866 diagram of a contraption designed for "The Chemical Testing of Wine and Spirits"; striking, vibrant photographs of Indonesia's Kawah Ijen volcano, which produces a blue lava; and a vintage advertisement for plastics from the Dow Chemical Company.