The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com Hydrogen / Hydrocarbon Spark Gap / Arc Gap Thanks to Cip for the 3" tubing! Hydrogen or Hydrocarbon gas spark gap - with water cooled heat sinks. Upper Gap electrode, tungsten carbide, .371" diameter, .032" feed through hole (Calypso Waterjet nozzle - Ingersoll Rand model) Bottom electrode, 3/4" diameter tungsten with exhaust holes for oxygen Mica insulating washer in place... Exhaust holes for  combustion products, heavier oxygen sinks Sik covered wire "wick".  The wick restricts the flow of the liquid (alcohol, turpentine)  yet draws the liquid slowly, like a slow siphon... From bottom to top, we have exhaust, bottom electrode, mica washer, top electrode, water cooling section (with finned heatsink), hydrocarbon reservoir. Components so far...