This theoretical investigation was undertaken in an attempt to explain some unexpected experimental results which are described in detail in another paper. The fog droplets are assumed to be dielectric spheres with an index of refraction of 1.33 and the development is based on the work of Mie and Debye on the pressure of light and the colors of colloidal solutions. The results show that the particle size of the fog is a controlling factor in the transmission characteristics of the fog. By assuming the appropriate particle size a theoretical transmission curve is obtained which closely corresponds to the experimental data. In conclusion, it is pointed out that the King formula is not applicable to the scattering of light by particles as large as fog drops.

• Received 23 March 1931

DOI:https://doi.org/10.1103/PhysRev.38.159