In 1822, keeper Benajah Wolcott lit 13 oil lamps atop the new lighthouse on Ohio's Marblehead Peninsula, establishing what became the oldest continuously operating beacon on the Great Lakes for mariners sailing between Detroit and Cleveland. Its original whale-oil lamps, copied from the French Argand lamp, with reflectors and a heavy lantern structure, were crude, poorly designed, difficult to maintain, and partly obstructed by copper sash bars and corner posts, yet this standard arrangement remained for 30 years. In 1852, Congress created the U.S. Lighthouse Board, which introduced technical advances already used in Europe, and in 1858 a fourth-order Fresnel lens replaced the original reflectors with a 28-inch-tall, barrel-shaped prism assembly around a single lard-oil lamp that produced a fixed white light visible all around the horizon. In 1903, as shipping increased, Marblehead received a three-and-a-half-order Fresnel lens, 66 inches across each face, rotated by clockwork around a larger kerosene lamp so that it showed half-second white flashes every 10 seconds, a distinctive characteristic that helped navigators fix their positions at night. In 1914, an incandescent oil-vapor lamp provided a more effective light source, with the keeper pressurizing its kerosene tank by hand each day. In 1923, electricity replaced kerosene and allowed automatic changing of burned-out lamps, although clockwork still rotated the lens by hand winding every four hours, and within a few years a red glass chimney changed the flash from white to red. In 1972, the heavy bivalve lens was replaced by a 300 mm plastic navigation optic that flashed green every six seconds without clockwork or a keeper, while still using the principle established by Fresnel in the early 1800s. The structure and equipment also evolved: the ventilator ball improved draft and reduced condensation; the cast-iron-framed lantern installed in 1901 had first topped Erie, Pennsylvania's first lighthouse in 1867; curtains protected the lens assembly from sunlight and possible explosion; the three-and-a-half-order bivalve Fresnel lens used 128 prisms to form two beams visible for 16 miles and rotated on 30 ball bearings; gallery decks aided weather observation, shipping watch, and maintenance; service and watch rooms housed the mechanism, supplies, and a hand-operated foghorn; and the keeper climbed 87 steps within a limestone tower built in 1821, later enlarged internally by a brick cylinder and raised to 73 feet 6 inches. The architectural history ran from the tower's construction in 1821 by John Kelly, his 13-year-old son, and three helpers in 11 weeks, through the 1858 installation of a Fresnel lens and iron lantern, the 1898 masonry watch room and brick cylinder, the 1901 third-order lantern, a partial gallery enclosure in 1949 that was removed in 1956, and the 1974 repointing and concrete coating of the limestone with the dome and trim painted red.