NEMA’s sodium vapor high-intensity discharge (HID) lamps shipment index declined for the fourth consecutive quarter on a year-over-year basis, NEMA’s sodium vapor high-intensity discharge (HID) lamps ...

For almost two generations of Chicagoans, orange has been the color of night. High pressure sodium vapor lights, which create a glow reminiscent of a tire fire, have lit Chicago since the 1970s. They ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. As knowledge of materials and ...

IN many of the long stretches of main roads between towns and villages the only practical way of lighting at present seems to be by means of the lamps on the vehicles. In a paper on “Electric ...

The bland orange-yellow of sodium-vapor lamps now lights hundreds of miles of U. S. highway. Until recently it has been a ticklish and costly job to get the sodium into the highly evacuated lamps ...