( 165 ■) 



strated, if it rested exclusively on the data about cold winters. 

 (Table I First Communication). 



A purely accidental coincidence becomes inadmissible however, now 

 that we have found a similar fluctuation in different elements of the 

 sun's activity, the more so, where the possibility — nay probability — 

 of a causal connection between the two phenomena is obvious. This 

 conclusion is strengthened by the correlation between the sun's 

 activity and the temperature in tropical regions, found by Koppen and 



NORDMANN. 



On the other hand the exact nature of these fluctuations cannot 

 yet be established. 



The parallelism of the frequency of cold winters and the Relativ- 

 Zahlen is most strongly marked, if we take as a basis the period of 

 356 years=:32 eleven-year cj^cles (see tig. I of our First Communication). 



Moreover we find both in the sun's activity and in the climate 

 indications of a shorter period. Meanwhile it is only the 89-year 

 periodicity which appears clearly in our data. 



The matter may perhaps be cleared up by hypotheses about the 

 physical cause of the oscillations (hypotheses into which I have not 

 entered here). Therefore, what may be considered sufTiciently demon- 

 strated about the nature and the length of the periodicity, comes 

 to this : Retardation and weakening o f t h e 11-y ear 

 suns' oscillation together with a diminution of 

 the number of cold winters every 89 years. 



Moreover it seems sufficiently certain that strong deviations from tlie 

 "normal" 89-year oscillation occur at the aame time in the sun's activity 

 and in the climate. They are perhaps caused by the existence of a 

 still longer period (see for instance the considerable acceleration and 

 increase of the sun's oscillation in the latter half of the 11*^' 89-year 

 period — second half of the 18''^ century — and the exceptionally 

 high cold factors of that time). 



Finally' we may conclude from the whole of our investigation, and 

 this is perhaps the most important conclusion : that in connection with 

 meteorological phenomena, not only the frequency o f t h e 

 sun spots, but also other elements of the sun's 

 activity c u r ^ e deserve our attention. 



Of course the possibility of a prediction of certain characteristics 

 of the weather, long in advance, with a considerable degree of 

 probability, is contained in our result. 



Also its importance for explaining geographical and geological 

 phenomena is obvious. I do not now wish to enter into details about 

 these matters. 



