Next to the human need for food, shelter and clothing, comes the need for artificial light. The meeting of this requirement, upon a large scale, becomes an engineering proposition and electric lighting stands prime among various agencies used therefor, when illuminants are classified according to their effectiveness, adaptability, flexibility and efficiency.
There are few engineering activities which have advanced more rapidly during the last few years than have the art and practice of
electric lighting. Illuminants have been steadily improved and refined. New types of lamps have been developed giving better colors of light, more efficient light production, cheaper.units and a greater range of sizes.
