Life of Incandescent Lamps

The period of time a lamp remains in action before the carbon filament is destroyed. The cause of a lamp failing may be the volatilization of the carbon of the filament, causing it to become thin and to break; or the chamber may leak. The life of the lamp varies; 600 hours is a fair estimate. Sometimes they last several times this period. The higher the intensity at which they are used the shorter is their life. From their prime cost and the cost of current the most economical way to run them can be approximately calculated. [Transcriber's note: Contemporary in can decent buls are rated for 1000 hours; flourescent bulbs up to 24000 hours; LED lamps up to 100000 hours.]