The preceding contribution by Stetson is an outstanding one to our knowledge of extra‐terrestrial influences upon radio transmission. The writer is perhaps in a unique position to appreciate this work, for several years ago he searched for a lunar period in radio reception, obtained inconclusive results, and announced that there was little or no relation (The correlation of radio reception with solar activity and terrestrial magnetism, Proc. Inst. Radio Engin., v. 15, 92–93, February 1927); this discussion may be regarded as a recantation and abjuration of his former belief.