The effects of moving striations in a glow discharge on microwave standing‐wave patterns in a waveguide containing the discharge were measured. The data yielded estimates of the longitudinal variation of electron density along a striation which were compared to measured light intensity variations. It was found that there were large variations in both electron density and brightness with the brightness maximum just to the cathode side of the electron density maximum. These results are compared to the results of other investigations and some points of disagreement noted.