Dec, 1918] Are the Ten Thousand Smokes Real Volcanoes? 107 



vents were so much hotter than we had expected, that in 1917 

 we were entirely unprepared to measure their temperatures. 

 The expedition of 1918, however, went prepared to cope with 

 the situation. The records thus secured will be given in detail 

 in a paper which is to follow. It may be stated in advance 

 of detailed publication, however, that the temperatures meas- 

 ured ran above 400°C. 



In many places the vents occur in lines that very strikingly 

 suggest that their distribution is controlled by the presence of 

 subterranean faults or fissures, which have been concealed by the 



Photograph by R. F. Griggs 



THE SAME VENT FROM A LITTLE DISTANCE. 

 The steam is so hot that it does not condense until ten feet away from the vent. 

 Some idea of the scale may be gained from the realization that the little 

 steamer enclosed by the circle was our cook stove, shown close up on page 98. 



superficial layers of recent ejecta (see pages 108 and 109). In 

 other places they emerge directly from yawning fissures, but 

 the nature of the substratum is such that it is not easy to 

 ascertain whether these correspond with rock fissures or are of 

 a more superficial character. Where the vapor emerges from, 

 such wide open faults in the tuff that covers the Valley, it is 

 obvious that these might be merely the superficial avenues of 

 •escape from the tuff, rather than the orifices of the true vents. 



