March, 1919] Temperatures of Ten Thousand Smokes 259 



work others, it was necessary for one man to hold the recording 

 instrument while the other held the thermocouple and moved 

 it from crack to crack. In this way we recorded a number of 

 different temperatures from each area until we found the 

 maximum. 



3. Large steamers: Large irregular holes resulting from 

 the cave-in of the roofs of wide fissures. They emit a large 

 column of steam under pressure and are very conspicuous 

 and most common near the high mud mark along the edge 



Photograph by D. B. Church 



A PORTION OF THE EDGE OF THE CRATER OF No. 21. 



It was impossible to get a satisfcatory photograph of the interior, or to reach the 



bottom, but a small crack just within the rim gave a temperature of 196 C. 



of the Valley. The vent is always large and perhaps much 

 hotter than the temperature which we were able to secure 

 at the edge of the hole would indicate. (Example, No. 22, 

 page 273). 



4. Craters: Large crater-like orifices, evidently of explosive 

 origin and occurring generally in the floor of the Valley. Many 

 cracks and fissures radiate out from them. They are sur- 

 rounded by a ring of ejecta rising 15 or 20 feet above the Valley 

 floor and are very conspicuous because of the large amount 

 of steam given off. In no case was it possible to approach 

 the orifice from which the steam emerged to take the tern- 



