Production and application of light

Statistics on Incandescent Lamp Sales.
¹
The sale of large tungsten filament lamps (as distinguished from the miniature types) totaled 344,000,000 during 1929, an increase of 8.7 per cent over the previous year's sales. The fact that the production of large tungsten filament lamps alone is running well over a million lamps per working day will give some impression of the extent to which our modern life has become dependent upon this source of artificial illumination.