The Eclipsing System RX Cassiopeiae.

The photographic light-curve (2037 observations) and visual light-curve (324 observations) are com- bined with Struve's spectroscopic results to determine the relative and absolute dimensions. The whole light-curve undergoes a variation of range 0.46 mag. and period 517.6 days. The photographic light-curve shows a difference of 0.16 mag. between the maxima-the largest ever observed. An additional drop of brightness, of 0.08 mag., occurs just before primary minimum. The visual light-curve shows a much larger ellipticity of the components than the photographic light-curve. The relative dimensions are as follows: Major axis: G3, 0.39 (pg), 0.36 (vis); A5, 0.17 (pg), 0.28 (vis) Luminosity: G3, 0.43 (pg), 0.36 (vis); A5, 0.57 (pg), 0.64 (vis) Ratio of surface brightnesses (A5/G3): 7.2 (pg), 2.8 (vis) Ratio of radii (A5/G3): 0.43 (pg), 0.8 (vis) Inclination of orbit: 78.8° (pg