The lantern which was recovered from the H.L. Hunley submarine was not a carbide, or acetylene lamp. The carbide technology for lights was not invented until several decades after the American Civil War. The lantern found aboard the Hunley was an oil burning lamp, likely sperm whale oil; it had a bullseye lens, and was properly called a “dark lantern” due to its sliding shade which could reveal or hide the flame at the operator’s will. The “blue light” which was mentioned in the historical record of the engagement between the H.L. Hunley and the USS Housatonic was a pyrotechic firework signal in long use in both military and civilian sectors. It was not a magnesium light. The original formulae for its manufacture are listed in period US military texts, and I have reproduced it and tested it under conditions similar to those during the Hunley-Housatonic engagement. See YouTube: “Burning Blue Light” and “Making Civil War-Era Blue Light”