March, 1919] Temperatures of Ten Thousand Smokes 257 



Because of the prevalence of strong winds these gases did not 

 interfere with the work as much as might have been expected, 

 but they are an ever present menace and there are considerable 

 areas into which no explorer has yet dared to penetrate for fear 

 of being overwhelmed by the fumes from the thickly placed 

 vents. 



CLASSIFICATION OF FUMAROLES. 



Since the fumaroles of the Valley manifest an almost endless 

 variety of form, size and character, it is difficult to find any 

 satisfactory basis for their classification. Nevertheless it will 



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i-: 



Photograph by Jasper D. Sayre 



THE THROAT OF FUMAROLE 5 WITH THE THERMOCOUPLE HUNG 

 DOWN SIX FEET INTO THE HOLE. 



The temperature was 231° C. at this place. The steam did not condense until 

 some distance from the throat. This fumarole is shown from a distance 



on page 252. 



conduce to clearness of thinking to separate them roughly 

 into the following groups. But it must be recognized that there 

 are no distinct lines to be drawn between the different cate- 

 gories, for they intergrade in every way. 



1. Chimneys: Isolated single holes on the general level 

 of the surrounding Valley floor, with chimney-like throats. 

 There was no surface indication of a lengthy fissure nor of ejecta 

 thrown out around them. The temperature was usually high, 

 (Example No. 5, page 265). These chimney-like fumaroles are 



