ARCTOWSKL VOLCANIC DUST VEILS 155 



in the Xational Geogiaphic Magazine.^® A summary of the effects of 

 the Katmai eruption on atmospheric optical phenomena has been given 

 b}^ J. Maurer and C. Dorno.^® 



The fact that the Katmai eruption occurred in a far northern latitude, 

 and has not been followed by similar volcanic outbreaks in other parts 

 of the world, is most valuable. Since the general atmospheric circulation 

 of the southern hemisphere is independent of that of the northern hemi- 

 sphere, it is difficult to imagine how the haze produced by the Katmai 

 eruption could have been carried south of the equator. If therefore we 

 observe, on the temperature curves of stations belonging to the southern 

 hemisphere, great similarities in the details of the curves of stations 

 belonging to the northern hemisphere, attributed to the presence of vol- 

 canic haze, it is evident that, however incomplete our knowledge of the 

 general atmospheric circulation may be considered, the supposed volcanic 

 dust influence must be discarded. 



Some argumentation, however, leaves the question open for discussion. 

 The correlations between the seasonal variations of far distant stations, 

 first noticed by H. W. Dove^^, then later more extensively studied by 

 n. F. Blanford,*! H. H. Hildebrandsson,*^ J. Hann,*^ H. G. Lyons,** 

 Felix M. Exner,*^ E. C. Mossman^^ and others, show that one may pre- 

 sume that an anomaly at one "center of action^^ of atmospheric circula- 

 tion of one hemisphere will produce a similar anomaly at a corresponding 

 station belonging to a correlated "center of action" of the other hemi- 

 sphere. I suppose that the number of stations for which temperature 

 records have been compared is sufficient to eliminate the possibility of 

 such an aro-ument. 



38 George C. Martin : "The Recent Eruption of Katmai Volcano in Alaska," Nat. 

 Geog. Mag., vol. 24, p. 131. 1913. 



39 J. Maurer and C. Dorxo : "Ueber den Verlauf und die geographische Verbreitung 

 der atmospheriscb-optischen Storung 1912-1913," Meteor. Zeit., vol. 31, p. 49. 1914. 



*° H. W. Dove : Nicht periodische Verandemngen der Verbreitung der Wlirme auf dor 

 Erdoberflache. Berlin. 1869. 



*i H. F. Blaxford : "On the Barometric See-saw between Russia and India in the 

 Sun-spot Cycle," Nature, vol. 21, p. 477. 1S80. 



*2 H. H. HiLDEBRAXDSSOX : "Quelques recherches sur les centres d'action de I'atmos- 

 phere," K. Svenska Vetensk. Akad. Handlingar, vol. 29, no. 3, vol. 32. no. 4, vol. 4.5, 

 no. 2, vol. 45, no. 11. 1897, 1899, 1909, 1910. 



*3 .T. Haxx : "Die Anomalien der Witterung auf Island in dem Zeitraume 1851-1900 

 und deren Beziehungen zu den gleichzeitigen Witterungsanomalien in Nordwesteuropa," 

 Sitz. Math, nat Kl. K. Akad. d. Wiss., vol. 113, II a, p. 183. Wien, 1904. 



^* H. G. Ltoxs : The Physiography of the River Nile and its Basin. Cairo, 190(1. 



•^"^ Felix M. Exxer : "Ueber monatliche Witterungsanomalien auf der nordlichen Erd- 

 halfte im Winter," Sitz, K. Akad. Wiss. Math.-Naturw. Klasse., vol. 122, II a, p. 1165. 

 Wien, 1913. 



*° R. C. MossMAX : "Southern Hemisphere Seasonal Correlations," Symons's Met. Mag., 

 vol. 48. London, 1913. 



