Abstract
The following table contains the final relative sunspot‐numbers for 1928 and 1929, for the whole disc of the Sun based on observations made at the Zurich Observatory, supplemented by series furnished by other cooperating observatories for days when no observations were made at Zurich. It will be noticed that the mean for the year 1928 (77.8) shows an increase of 8.8 over that for 1927 (69.0) whereas that for 1929 (65.0) indicates a decrease of 12.8 as compared with 1928.The figures below give graphical representation of the daily relative sunspot‐numbers for 1928 and 1929, the times being plotted as abscissas and the relative numbers as ordinales. The limits of the successive solar rotations are indicated by vertical arrows in the upper edge of the figures. A preliminary consideration of the observed and smoothed numbers from 1923 to 1930 indicates the epoch of maximum near 1928.5.
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