c. 1890-1910 original antique american-made victorian era copper-plated ornamental cast iron wall-mount thermostat control cover or fixture designed and fabricated by the electric heat regulator co., minneapolis, mn. the original internal components were removed long ago. the nickel-plated brass temperature scale is original and tightly soldered to the backside of the cover plate. the thermostat cover contains the distinctive monogrammed logo featuring radiating waves located below the opening for the adjustable temperature controller. the copper-plated finish remains largely intact. in 1883 inventor albert butz developed the process of automatic temperature control, connecting a thermostat to a spring motor to operate home furnace dampers according to changes in air temperature. in 1885 he filed for his first temperature control patent, and formed the butz thermo-electric regulator company. butz's company was incorporated in 1886. in 1888 he sold his business, which was incorporated as the consolidated temperature controlling company. the firm was renamed the electric thermostat company in 1892, and the electric heat regulator company in 1893. measures 3 1/2 x 1/2 x 11 inches.