VIEWS OF BRUN AND GREEN 575 



It is not our purpose to discuss this question at this time except in so 

 far as it may find application in the volcano Kilauea on the Island of 

 Hawaii, but this volcano provided all of the material for Green's discus- 

 sion and a very essential portion of that offered by Bran. It will there- 

 fore be of interest to record some observations made in the course of an 

 extended study of this volcano by the writers during the summers of 1911 

 and 1912. The purpose of these studies is to obtain definite information 

 about the character of the chemical reactions which take place in an active 

 volcano, and in particular to determine the role played by the gaseous 

 Components, which are very important factors in both its chemical and 

 physical activities. In many studies of volcanoes the gases have been 

 allowed to escape entirely, while in others they were not captured until 

 the nature of the components was so much altered by oxidation or other- 

 wise that their identification, to say nothing of the determination of their 

 relative proportions and the character of the equilibrium existing between 

 them, has remained uncertain, On these broader questions, which are 

 laboratory problems, most of the work still remains to be done. It is, 

 however, quite possible to offer evidence on the participation of water 

 and of some of the other volatile ingredients in the activity of Kilauea in 

 advance of this study, which, may require some years before all the ques- 

 tions which have been raised are satisfactorily elucidated. 



Discussion of the Observations of Green and Brun 



First let us~ review somewhat briefly the observations which led Green 

 and Brun to the same novel conclusion, that water has no part in the vol- 

 canic activity of Kilauea. In the case of Green, such a review is not alto- 

 gether easy. His reasoning is based on deductions from many phe- 

 nomena, such as appeal to an observer on the ground: great lava streams 

 without a trace of vapor rising from them ; a condition of great activity 

 in the lava pit of Halemaumau (the only portion of the Kilauea volcano 

 now continuously active), with hardly a trace of any cloud above it; a 

 rather conspicuous difference in character between the Halemaumau cloud 

 (when there is one) and the clouds which arise from numerous steam 

 cracks in the country round about, etcetera. Perhaps the chief factor 

 which clinched his conclusion was the fact (which we also observed) that 

 there are times when a magnificent cloud rises from the active basin, sepa- 

 rated by but a day or two from periods when practically no cloud can be 

 seen, and this with no apparent change either in the character or amount 

 of activity visible in the basin. He therefore concluded that if steam was 

 the moving force, and if the great white cloud was the manifestation of 



