Archaeological investigations of a burned 1916-1919 United States Army
building at Fort Rosecrans, San Diego, California (CA-SDI-12,000) exposed a number
of carbon rods of various sizes. Although some were undoubtedly from
batteries, other larger ones were associated with search lights used for coast
artillery sighting. I too have wondered how those were made and how long the
technology has been around.
Ron May
Legacy 106, Inc.