Fast facts about Split Rock Lighthouse
The Split Rock Lighthouse was in operation from 1910 to 1969. Here are some facts about the site:
- Lake Superior elevation - 602 feet above sea level.
- Cliff height - 130 feet.
- Tower height - 54 feet.
- Light source - incandescent oil-vapor (kerosene) lamp, 1910-39; 1,000-watt electric bulb, 1940-1969.
- Lens - third-order bivalve Fresnel lens, manufactured by Barbier, Bernard and Turenne Company, Paris, France.
- Official range - 22 miles.
- Flashing sequence - once every 10 seconds (0.5-second flash every 9.5 seconds).
- Tone - siren blast, 1910-1935. Type F diaphone "be-you" sound, 1936-1961.
- Sounding sequence - 2-second blast, 18-second silence.
- Effective range - 5 miles.
- Powered by Franklin 30-horsepower gasoline-driven air compressors, manufactured by Chicago Pneumatic Tool Company, 1910-19031; diesel compressors, 1932-1961.