Screwpiles: The Forgotten Lighthouses

Image by Sheally

Fresnel Frenzy A law enacted March 3, 1851, required that all new lighthouses must use the Fresnel system. “Hereafter, in all new lighthouses, in all lighthouses requiring new lighting apparatus, and in all lighthouses as yet unsupplied with illuminating apparatus, the lens or Fresnel system shall be adopted, if, in the opinion of the Secretary of the Treasury, the public interest will be subserved thereby.” 1 There were so many new lighthouses under construction, all requiring the Fresnel lens, that the demand for lenses taxed the French supplier. An article appearing in the Washington (North Carolina) Journal , dated May 26, 1854, notes, “Four or five hundred workmen, comprising nearly

all engaged in that line of business, in Paris, are occupied on the American contract. There are but three establishments in the world for the manufacture of the improved French light, two in Paris, and one in St. Petersburg.” 2 Lenses Used The original specifications for the James River lighthouses required sixth-order Fresnel lenses. Because the Fresnel lenses were in short supply and available only from French suppliers, the Lighthouse Board looked for alternatives. Tests done in April 1855 showed that pressed-glass lenses would suffice in the case of the

127