BULL. GE 



51 ETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 26, pp. 375-388, PLS. 16-24 SEPTEMBER 3, 1915 



"SlH,}' ONDITIOX OK mK A^OLCANOES OF SOUTHEEN 



■It': ITALY 1 





/!»*'''» '-'>■ "• '^^ WASH IXCiTUN A.\L) AiriTiLi; L. DAY 



^^. :. ^J\r<i<l hcftirr llir. Socieh/ Dcrrinhfr -U. H^UJ/) 



:l CONTENTS 



■{ Page 



Introdi ^:'h'Aj ."^To 



Ve^^uviu^>;i.^f 376 



Etna . . . . T^' :{80 



Vulcaiio :584 



Stromboli 387 



N^TKODITCTORY 



The stvulies of I);iy ami Slioplici'd- at Kilauea liavo demonsfratpd the 

 presence of water in the unaltered hna gases at this volcano, and that 

 chlorine and fluorine are present only in very small amount. They have 

 also shown that the gases at the time <d' their escape from the lava were 

 in a state dI' unstahic chemical c(niililirium. and that tliey were under- 

 going interreactioiis whicli, heing exothci'inic, might in |iart cxphiin the 

 maintenance of tlie high temperature of the lava. 



Witlmut cntci'ing into discussion of these results, it may he said tliat 

 they Avere of such a character that it was deemed advisahle to cxteiul the 

 ohservations and studies to other Milcanoes. Ther(^ were several special 

 reasons for this. 



Tlie confirmation (d' the presence of watt'r at <ither xolcanoes was a 

 matter of interest in coniKH-tiou with l^run's hypothesis, though this may 

 now he considered as delinitidy disproved hy the Kilauea evidence. The 

 possibility of intiiiial. e\<ithiuiuic gas reactions serving to account, at 

 least in paiM. for tin- hi-h temperature of the lava made it a matter of 

 importance' to ascertain the coniposii ion of tlie magmatic gases, and tludr 

 possible interreaclioiis, at nther volcanoes. Furthermore, as it is now 

 recognized that the distrihut ion of the rarer elements is correlated with 



' Manuscript rccolvpii hy Ihp Secretary of the Society May '2r>. 1015. 

 2 Day and Shephrrd : .lour. Wash. .\cad. Scl.. vol. Ill, 1913, p. 4."i7 ; Bull. Cool. Soc. 

 Am., vol. 24. 1013, p. 573; Comptes Rcndu.s, vol. civil, 1913. pp. 958. 1027. 



XXIX— Bull. Geol. Soc. Am., Vol. 2G, 1914 (375) 



