Discharge lighting brightens the night

As part of an historical study of streetlighting in London (UK), the article examines how the gas discharge lamps of 1930 indicated the way ahead but were not the complete answer. They needed special circuits, with an inductance to control the current and usually some way of producing a high voltage to strike the arc, but the higher efficiency compared with filament lamps made that worthwhile. The real problems facing designers and manufacturers of discharge lamps were materials. They needed materials for the arc tube and for the electrodes that would resist chemical attack from the hot ionized gases in the tube. In any event, the high-pressure mercury lamp and the sodium lamp were developed almost simultaneously. Today these lamps dominate street lighting as well as flood light applications.