Prediction of Sunspot Numbers for Cycle 20

Abstract

IN a recent communication, P. Herrinck¹ has given a table of predicted sunspot numbers for the current solar cycle (No. 19), based upon the striking coincidence of values between the two periods 1749–85 and 1918–54. A good fit was obtained by multiplying figures observed 169 years before by a factor of proportion. This means, essentially, that cycles 16, 17, and 18 have been made to correspond with the cycles 169 years earlier, namely, cycles 1, 2, and 3, respectively.