Yorktown Lightship Lens Virginia
Until the invention of the refracted lens by French physicist Augustin Fresnel in 1822, illumination for lighthouses and vessels was dependent on lanterns and lamps with rudimentary reflectors. Ironically, it was at almost the same time that the "first outside vessel was placed off the coast of the United States," in Chesapeake Bay, off Craney Island, at the entrance to the Elizabeth River.
The light to warn mariners was suspended from the top of the mast, and either required that a seaman climb the mast to keep the oil filled and re-light wind-extinguished flames, or the lantern had to be raised and lowered by ropes. Needless to say, this was an important and tiresome task for the lightship crew.
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