Quartz fiber is made from heating quartz rods with an oxyhydrogen flame. Because of the explosiveness of the oxyhydrogen, limelights have been replaced by electric lighting. "Brown's gas" and HHO are terms for oxyhydrogen mainly encountered in fringe science. Also, vehicles with internal combustion engines may be converted to hydrogen or oxyhydrogen combustion. Oxyhydrogen will combust when brought to its autoignition temperature. Oxyhydrogen is a mixture of hydrogen (H) and oxygen (O) gases. The word "Knallgas" means "oxyhydrogen" (a mixture of hydrogen and oxygen, literally "bang-gas") in German.