II. On the periodicities of sunspots

Abstract

1. The material used in this investigation consists of:- (a) The series of sunspot numbers collected by Dr. A. Wolf and Dr. A. Wolfer, and published by the latter in his “Astronomische Mitteilungen.” This series contains for each month of the years 1749 to 1901 the sunspot frequency as expressed in Wolf’s “Relativzahlen.” (b) The mean daily areas during each synodic revolution of the sun from January, 1832, to the end of 1900, which have been collected and are issued as a separate publication by the Solar Physics Committee. The publications of the Greenwich Observatory allow us to continue this series to the end of 1902.