The carbon arc-a valuable industrial tool

The versatility of the carbon arc as a source of both visible and invisible radiation is shown to be due, in part, to the three basic types of operation to which it is adapted and also to the fact that the character of its energy emission can be modified by changes in core composition. It is used in its various forms for many photochemical and irradiation processes, some of which require specific bands of ultraviolet radiation or close reproduction of the effects of natural sunlight. The carbon arc is preferred in other instances, because the optical requirements of the application necessitate a light source of small area and extreme brilliancy. Several industrial and commercial uses are cited together with the characteristics which give preference to the carbon arc as a source of radiation.