WE may well speak of. Our age as an Age of Artificial Light. Where formerly men were obliged to exist with only pine knots and candles to lighten their paths, we are now not only ﬂooded with light but better and cheaper sources are being continually devised. The illuminating engineer counts that year lost which does not see some marked advance in the art of producing light. Among all the contestants for popular favor there is one source of light which stands as undisputed king. Other lights may answer the need of the worker at the desk, but when one wants light of the most brilliant sort, one turns to the electric arc.