A Radiometric Investigation of the Germicidal Action of Ultra-violet radiation

Abstract

In the present investigation an attempt is made to determine the energy relations involved in abiotic action, thus placing the results upon a radiometric basis. By means of screens of mica, and of glass, successive portions of the ultra-violet spectrum are eliminated and the effects upon the resulting germicidal action established. The novelty in the present investigation consisted in making an application of the discovery that mica has a well-defined absorption band at about 260 m/x. A small variation in thickness of the mica screen produces a large variation in transmission in this spec- tral region relative to the rest of the spectrum, thereby permitting an increase in the intensity of the radiation stimulus of these wave lengths, while other conditions re- mained practically constant.