.">■/"' Ue/;'r.' />'/v/../.vv,.,7. /V^'-/- 



Plate 1, 



Curve « represents the Sunspot Frequency. 



Curve 2 represents Uie Frequeniy of Aurorte Boreales seen in Europe between Int. 46° and 65" N. 

 Curve 3 represents the Frequency of Anrorw Boreales saea in America betwren Int. and 6U'' N. 

 Curve 4 represents the Freiiucncy uf Aurora: Boreales seen in Europe up to the Arctic Circli.-. 



Illustrating Professor Schusters icipir on i/tr (.'onnrction hctwt'CKSun Spots unr/ j'cfrestnal P/wnomena 



