Statistics of Stellar Color Excesses.

In this paper the color excesses of stars are analyzed statistically with a view to deriving information regarding the main characteristics of the distribution of interstellar reddening dust. The problem of describing a given collection of color excesses in terms of the discrete cloud of Ambarzumian is considered in detail. It is shown how any frequency-curve of observed color excesses of stars in a fixed distance range can be uniquely interpreted in terms of a probability density for the color excesses that individual clouds may produce. Cn the basis of the color observations of Stebbins, Huffer, and Whitford, an attempt has been made to evaluate the mean value, the standard deviation, and the skewness of the optical thicknesses of the hypothetical interstellar clouds.