NATURE 



IMay I, 1877 



ytt tolly awake to a true measure of our responsibility or 

 to liic ncces;ily of keeping a continuous watch upon the 



sun. It may perhaps be desirable here to revie.v the 

 somewhat heterogeneous mass ol evidence from various 



Solar Spots, Magnetic Declination, and Auroral DisPLAYSt 



NUMBER OF, AUfiORA 



IS^^^^BAFRVeO EA&Hk YEAfi 



quarters which leads us to believe in the existence of I About fifty years aeo a careful observer, Ho^ratb 

 these peculiar relations. | Schwabe, of Dessau, with true Teutonic persistence set 



himself to observe the sun's surface day after day, and as I the discovery of a cycle in the frequency of SDOt= 

 Ihe result of forty years' observations, he was rewarded by | will be seen from the following table : 



This 



