In the New Jersey shore community of Sea Girt, where Commodore Robert Stockton's oceanfront mansion had a porch as long as a ship's deck from which he surveyed the waters, a lighthouse was built in 1896. Sea Girt Lighthouse illuminated a dark space, providing a crucial guiding light to passing ships. The station would become a lighthouse of distinction and innovation. In 1920, it was the first land-based lighthouse with a radio beacon transmitter,...