276 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



no part in volcanic activity. His words are as follows (p. 249, fol- 

 lowing a detailed statement of- reasons which will be considered 

 below) : 



II est done parfaitement certain que le volcan paroxysmal n'exhale pas d'eau. 

 La preuve est faite. Le grand panache Mane est compos6 de particules solides 

 et anhydres. 



II faut done que la tMorie aqueuse disparaisse de la science. 



(The italics are Brun's.) 



Except for these two conspicuous instances, students of vulcanism 

 have generally concluded^ that water is usually if not always the 

 chief agent in volcanic activity. 



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 

 discussion and a very essential portion of that offered by Brun. It 

 will therefore 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 re- 

 actions 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 otherwise that 

 their identification, to say nothing of the determination of tlieir 

 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 partici- 

 pation of water and of some of the other volatile ingredients in the 

 activity of Kilauea in advance of this stud3% which may require some 

 years before all the questions which have been raised are satisfac- 

 torily 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 volcanic activity of Kilauea. In the case of Green such a 



1 G. Poulett Scrope : " Volcanoes," London, 1872. John W. Judd : " Volcanoes, what 

 they are and what they teach," Loudon, 1881. James D. Dana: "Characteristics of 

 volcanoes," New York, 1891. A. Geikle : ^'Textbook of geology," vol. 1, London, 1903. 

 S. AiTheniua : " Lehrbuch der Cosmlschen Physik," Leipzig, 1903. It should perhaps be 

 added that some hare expressed the opinion that the importance of water has been over- 

 ostlmated, without explicit denial of its participation in volcanic activity. (See, for 

 example, J. G. Bornemann : " Ueber Schlakenkegel und Laven, ein Beitrag zur Lchre vom 

 Vulkanismus," Jahrb. d. Kgl. pr. geol. Landesanstalt, u. Bergakad, 1887, p. 230.) 



