THE “remarkable lightning flash” depicted by Mr. George G. Burch in NATURE for September 24, is to me interesting. Many years ago I witnessed what was probably a flash of the same kind, a phenomenon I considered at the time very extraordinary. In the early evening of a fine summer day, while sitting leisurely on a hedge on a comparatively high hill near to Llandyssul in the county of Cardigan, with an immense area of country within reach of my vision, there appeared, slightly above the horizon in the west, what seemed to be a perfectly endless flash, almost circular in shape, and exceedingly serrated.