Abstract :
ULTRA-VIOLET LIGHT An article in the May, 1922, General Electric Review by Llora C. Krueger entitled, “Ultra-Violet Light, Its Uses and Possibilities,” briefly outlines the early history of ultra-violet light. Modern theories treat radiation as a propagation of energy in the form of waves which have been shown to vary continuously in length from twenty to thirty thousand meters, in the wireless region, to the extremely short disturbances involved in X-rays. The visible spectrum covers only a very short range of these waves, extending from 7600 to 3900 Angstrom units. Ultra-violet light is produced in many ways, but few of them are sources of much energy. All artificial light contains more or less ultra-violet radiation and the sun emits a continuous spectrum of great intensity, but wave lengths shorter than 2950 Angstroms are absorbed by the atmosphere to such an extent that very little ultra-violet light reaches the surface of the earth.
