Notes: "This polar planimeter was made by A. Ott of Germany, and sold by F. Weber & Co., which was and still is a giant in the art supplies business, and for a while ventured into the engineering supplies market, selling slide rules made by Nestler and planimeters by Ott and Coradi. This planimeter is marked with both the Ott and Weber names, along with the Weber model number, 4304, and the Ott serial number, 1638."
