Van Dorn lamppost mailbox
This is a Van Dorn manufactured collection box made for attaching to street lampposts. The Van Dorn Iron Works Company of Cleveland, Ohio, held several contracts for manufacturing collection boxes for the Post Office Department for the first two decades of the twentieth century. Although the Van Dorn boxes were resistant to inclement weather, they were considered unattractive. In some cities postmasters removed the boxes from scenic boulevards where they were out of harmony with the ornate electric light posts, decorative fire alarms, and police telephone poles.
"Vanishing Americana: Lamp Post Letter Boxes." By James H. Bruns and Michael J. Lilly. Unpublished paper.