prevent breakage. Shattering of the arc tube may be avoided by replacing the lamp if there is an excessive blackening of the arc tube, the arc tube begins to swell, there is a sudden changing of the light color, or the lamp begins to cycle on and off. Gallery See also Arc lamp Hydrargyrum medium-arc iodide lamp - high power metal-halide lamps as used in cinematography Mercury-vapor lamp Sodium-vapor lamp Neon lamp Sulfur lamp Charles Proteus Steinmetz References Further reading Raymond Kane, Heinz Sell Revolution in lamps: a chronicle of 50 years of progress (2nd ed.), The Fairmont Press, Inc. 2001 Gas discharge lamps