Low-voltage fluorescent lamps

Colored light usually is obtainable from incandescent lamps only by means of some special filtering material, at relatively low efficiency. Now a new type of lamp, which is tubular in shape and contains a powder that becomes fluorescent in the presence of ultraviolet radiation, produces white light similar in character to daylight, as well as monochromatic light, at efficiencies much larger than those ordinarily associated with incandescent lamps.