An apparatus for the determination of the dew point

Abstract

The paper describes an optical system which, using diffraction by the dew droplets on a mirror, aids greatly the visual detection of dew formation. Then follows an account of the application of this system to an automatic photoelectric apparatus for maintaining a mirror at the dew point. Results are given of experiments made to find the effect on the accuracy obtainable of the difference between atmospheric temp and the dew point, and of varying air velocities round the apparatus.