BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 24, PP. 573-606, PLS. 17-27 DECEMBER 16, 1913 



WATEK AND VOLCANIC ACTIVITY 



BY ARTHUR L. DAY AND E. S. SHEPHERD 



(Read before the Society December 31, 1912) 



CONTENTS 



Page 



Green's view that the Kilauea emanation is anhydrous 573 



Brun maintains the same view 574 



Discussion of the observations of Green and Brun 575 



The explanation of the volcano cloud 577 



Bran's hygrometric observations 578 



An attempt to collect the volcano gases before they reached the air 581 



The second attempt to collect gases 583 



Chemical study of the material collected 584 



Analyses of the lava 585 



The gases and different ways of studying them 586 



Analyses of the gases collected in May, 1912 588 



The influence of the iron collecting tube 588 



The reaction between H 2 and S0 2 or C0 2 590 



The relative quantities of the constituent gases 591 



Preliminary analysis of one tube of gas in Honolulu 592 



The material present in the water 592 



Rare gases 593 



The gases collected in December, 1912 594 



The hot emanations from cracks about the Halemaumau crater 595 



Sublimation and decomposition products 597 



Discussion of results 598 



General conclusions 598 



The effect of the reactions between the gases 598 



The effect of the expansion of the gases 598 



An explanation of the formation of Aa lava 599 



Chemical reaction between the gases 599 



Variations in the composition of the gases 601 



Variations of lava temperature resulting from the gas reactions 601 



Explosive lavas (Bran) 601 



Water and the basic minerals 002 



Origin of the water 603 



Green's View that the Kilauea Emanation is Anhydrous 

 In a book, 1 now little known and rare, William Lowthian Green, a dis- 



* Vestiges of the Molten Globe, part 11, 1887, p. 82. (573) 



XL — Bull. Geol. Soc. Am., Vol, 24, 1912 



