ARCTOWSKI, VOLCANIC DUST VEILS 



173 



pleions of the years 1883, 1902 and 1912 and the exceptional!}' violent 

 volcanic eruptions which occurred simultaneously, shows that it may be 

 that the volcanic agencies are affected by the same extra-terrestrial factors 

 which influence climatic conditions. 



How this could be, is a most interesting question leading to many 

 investigations. One may presume, for example, some correlations be- 

 tween the pleionian variation and storm frequency and storm intensity 



Pig. 7. — World's temperature and the variatio)i of the frequency of volcanic eruptions 



and then a correlation between the more or less accentuated rapid oscilla- 

 tions of atmospheric pressure and volcanic eruptions. 



A relationship between the mean values of interdiurnal differences of 

 atmospheric pressure and the solar cvcle has been discovered by E. 

 Merecki,'^* and, on the other hand, the much discussed relation between 

 barometric changes from day to day, and the frequency of seismic and 

 volcanic phenomena may be accepted as an established fact.'^^ One may 



'8 R. Merecki : "Wplyw zmlennej dzialalnoscl slouca na czynniki meteorologiczne 

 ziemske," Prace mat.-fizyczne, vol. 19, p. 131. Warszawa, 1908. 



■^8 F. Omori : "Note on the Long-period Variations of the Atmospheric Pressure," Bull. 

 Imp. Earthq. Invest. Comm., vol. 2, p. 215. Tokyo, 1908. 



H. J. Johnsto-V-Lavis : "The Relationship of the Activity of Vesuvius to Certain 

 Meteorological and Astronomical Phenomena," Proc. Roy. Soc. London, vol. 40, p. 248. 

 1886. 



