A PAPER on this subject, read recently by L. J. Davies, H. R. Ruff and W. J. Scott before the Institution of Electrical Engineers in London, gives a brief history of fluorescent lighting and follows this by a description of a typical mains-voltage tubular fluorescent lamp and the principles of its operation. The new fluorescent lamp combines the high efficiency of the straight electric discharge lamp, with much of the convenience of operation of the incandescent lamp, while possessing, in addition, special characteristics of low brightness, exceptional colour-rendering power, and comparative absence of radiant heat. The 200/250-v., 80-watt lamp and its auxiliaries, marketed in Great Britain in March 1940 to improve factory lighting in blackout conditions, are described in detail and the characteristics and components of the complete unit are explained. This lamp is 5 ft. long and 1 1/2 in. in diameter, taking 0.8 amp. at a lamp voltage of 115 ; its nominal luminous efficiency is 35 lumens/watt and its mean brightness is 3.3 candles/sq. in. Its high electric power/light conversion ratio is examined together with the conventions whereby these are assessed. The paper concentrates attention upon the practical features of the lamp, but gives a sufficient description of the physics involved to promote an appreciation of both the present characteristics and future importance of this type of light source. The authors conclude that the lamp is satisfactorily fulfilling a present industrial need, and that its quality has been so greatly appreciated that it is undoubtedly the forerunner of a new series of lighting lamps.