Postcard to Joseph Hirshhorn, November 5, 1955, Smithsonian Archives - History Div, Postcard of a piece of artwork with black and white designs. The bottom right corner says "CA 61." The message side has a short message to Joseph Hirshhorn, the founding donor of the Hirshhorn Museum and Sculpture Garden, from the artist Alexander Calder. The card is postmarked November 5, 1955. The message is as follows:, "we're here for a bit. When are you coming up? Cordially Calder".