Marblehead Lighthouse

Marblehead Lighthouse. , Lamps, Lenses, and Lanterns , 1822 When keeper Benajah Wolcott lit the 13 oil lamps atop the new lighthouse on Ohio's Marblehead Peninsula, he kindled what would become the oldest continuously operating beacon on the Great Lakes. Mariners sailing between Detroit and Cleveland welcomed it, although the appar- atus was crude even for 1822., The whale-oil lamps (copies of the French Argand lamp introduced 40 years earlier) and reflectors were poorly designed, shoddily made, and hard to maintain. The lantern's heavy copper sash bars and corner posts interfered with the light. But the arrangement was standard issue, and remained so for another 30 years., 1852 Responding to shipping- industry pressure, Congress created the U.S. Lighthouse Board. The board ushered in technical advances that had been saving European lives and vessels since the 1820s. By the Civil War, most American lighthouses would be equipped with trim, iron-framed lanterns and efficient lenses invented by Augustin Fresnel., 1858 A fourth-order Fresnel lens replaced the original reflectors. The new lens was a barrel-shaped assembly of prisms 28 inches tall, surrounding a single, bright lard-oil lamp and concentrating its rays into a fixed (constant) white light visible all around the horizon., 1903 As shipping boomed, the Lighthouse Board equipped Marblehead with a three-and-a-half- order lens (a two-part Fresnel lens, 66 inches across each face). Clockwork turned it around a larger, brighter kerosene lamp, sending out beams that appeared to an observer as half-second white flashes every 10 seconds. Marblehead's unique light pattern, called its characteristic, distinguished it from other beacons and so helped navigators determine their positions at night., 1914 Marblehead acquired an even more effective light source, an incandescent oil-vapor lamp. The keeper pressurized its kero- sene tank, mounted next to the lens, once a day with air from a cylinder that was pumped by hand., 1923 The march of technology continued: Electricity took over from kerosene, making possible a device that changed burnt-out lamps automatically. But clock- work, wound by hand every four hours, still rotated the lens. In a few years, a red glass chimney would modify Marblehead's char- acteristic flash from white to red., 1972 The heavy bivalve lens gave way to a plastic navigation optic, 300 mm in diameter, that flashed green every six seconds, without the aid of clockwork or a keeper. The new lens employed the same principle that Fresnel established in the early 1800s., 1 Ventilator ball , Topped by a lightning rod, the ventilator provided the draft that kept the lamp burning brightly, and dispelled condensation that could cloud the lantern's windows., 2 Lantern , Originally, this cast-iron-framed lantern topped the first lighthouse in Erie, Pennsylvania, where it had been installed in 1867. In 1901 it became Marblehead's third superstructure and was designated a third-order lantern in a rating system worked out by Fresnel. A sheet-metal cowl kept the lamp and lens dry should the copper dome leak. Curtains inside the lantern, hung during the day, screened out sunlight that could have damaged the compound securing the lens prisms, or-focused through the lens onto the lamp-set off an explosion., 3 Lens , The three-and-a-half order Fresnel lens was called a "bivalve" because of its clamshell shape and configuration. A total of 128 prisms refracted the lamp's rays into two powerful beams, visible for 16 miles. Clockwork rotated the 1,400-pound lens three times a minute. It turned on 30 three-quarter-inch ball bearings, its speed precisely regulated by a fan governor. The second-order moderator lamp inside the lensburned 1.2 pints of kerosene per hour., 4 Upper gallery deck , The keeper climbed up here to clear the lantern windows of snow and ice. Handholds on corner posts offered a secure grip in high winds and icy conditions., 5 Gallery deck , With a 360-degree view of Lake Erie and Sandusky Bay, the gallery deck facilitated two of the keeper's duties: to record the weather and to monitor shipping., 6 Service room , Both lamp and clockwork needed frequent maintenance, most of which the keeper performed in the service room. From this level, the weight that powered the clockwork dropped slowly down a 54-foot iron tube to the tower's base. 7 Watch room , Here the keeper had a sheltered, if narrow, view of the lake. Closets held a back-up lamp with extra burners, glass chimneys, and wicks, as well as other supplies, tools, and a hand- operated foghorn. For safety, only a small supply of kerosene was kept in the watch room; it was replenished from a five- gallon can at the base of the tower The main supply was a circular, 225-gallon oil house 10 feet from the lighthouse; its use was discontinued when a square, 600-gallon structure was added in 1906., 8 Cast-iron stairway , The keeper climbed 87 steps to reach the lantern. The outside ends of the lower stairway's treads and risers were securely embedded in brickwork., 9 Limestone tower , When it was built, the tower stood 55 feet high and measured 25 feet in diameter at the base. The walls, 5 feet thick at ground level, tapered to 21⁄2 feet at the top. Before the fourth-order lantern was added, the interior ledges supported wooden floors, connected by wooden stairs. Still visible on the outside of the tower in 1903 were sockets that held scaffolding during the 1821 construction., 10 Brick cylinder , The watch room was essentially the upper end of a cylindrical brick tower built inside the original lighthouse. Its purpose was to widen the upper end of the limestone structure and support a larger, heavier lantern and lighting apparatus. During the renovation, four new window bays were cut through the stonework and fitted with double-hung windows., Architectural Timeline of Marblehead Lighthouse-1821 through 1974. , 1821 John Kelly, his 13-year-old son, and three helpers built the tower of locally quarried limestone in 11 weeks., 1858 A Fresnel lens and iron lantern super- ceded the original lamps, reflectors, and bird cage-style lantern. Cast iron landings and stairs supplanted wooden floors and stairs., 1898 A masonry watch room, supported by an interior brick cylinder, replaced and widened the tower's upper eight feet of stone., 1901 The third-order lantern, added to accommodate the new three-and-a- half-order lens, increased the total tower height to 73 feet 6 inches., 1949 Half of the gallery deck was enclosed to protect the keeper from the weather while he monitored shipping. The enclo- sure was removed in 1956., 1974 The limestone was repointed and coated with concrete, and the dome and trim were painted red.