Ultraviolet quickly than violet light itself. He called them "oxidizing rays" to emphasize chemical reactivity and to distinguish them from "heat rays", discovered the previous year at the other end of the visible spectrum. The simpler term "chemical rays" was adopted shortly thereafter, and it remained popular throughout the 19th century, although there were those who held that these were an entirely different sort of radiation from light (notably John William Draper, who named them "tithonic rays"). The terms chemical rays and heat rays were eventually dropped in favor of ultraviolet and infrared radiation, respectively. In 1878 the sterilizing effect of
Ultraviolet light therapy Ultraviolet light therapy Ultraviolet light therapy or ultraviolet phototherapy is a form of treatment for certain skin disorders including atopic skin disorder and vitiligo when used with psoralen to form the PUVA treatment. It consists of irradiation of the patient with the UVA band of ultraviolet light (fairly closely matching the ultraviolet output from the sun), usually delivered from a fluorescent bulb specially designed to output this frequency of ultraviolet. This treatment is similar to the light from good quality solariums but differs from the mainly UVB ultraviolet band used to treat psoriasis. Tanning beds are used both in dermatology