276 The Ohio Journal of Science [Vol. XIX, No. 5, 



Globules of blue mud shot into the air with a pop and fell back into 

 its basin with a splash, only to be followed by many similar outbreaks 

 all around us. Going to windward we saw the seat of the trouble. 

 The ground was covered with boiling blue mud pots, some with a 

 consistency of well cooked mush, while in others the boiling water was 

 almost clear. It was impossible to secure satisfactory pictures of the 

 performance, because of the thick blanket of rising steam that covered 

 an area of an acre or more. The mud w^as blue black. The temperature 

 was that of steam, 100° C. Photographs 4146, 4151, 4152, 4558, 4560. 



Photograph by Paul R. Ilagelbarger 



PLACING THE THERMOCOUPLE IN FUMAROLE 33. 



This inconspicuous crack, with the thermocouple placed as in the picture, gave 

 a temperature of 432° C, the highest measured in the valley. The ground 

 near the fissure was too hot to stand on very long, so we supported the cold 

 junction of the thermocouple on a spade. 



No. 45. T. 412°C. IX, N low. X, S19W. Mt. Mageik, S 35 E. 



Between No. 33 and No. 36 and the east bank of the canyon from 

 Knife Peak Valley was a conspicuous steamer. As we approached it, 

 200 yards to the eastward, we came upon the end of the fissure which 

 gave forth a big column of steam where it was crossed by the Canyon. 

 The deposits here were light colored. At different places in the small 

 cracks in the roof of the fissure the temperatures were 289° C., 318° C, 

 387° C, 412° C, 402° C., 397° C. The main steamer, we found, 

 had a temperature of 3()0° C. at the surface of the ground. 



No. 1^6. T. 171°C. 500 yards south of No. 22. 



This fumarole was on the sam.e line of activity as No. 22, and was 

 very similar to No. 22 and No. 47. It was a large circular hole in the 

 roof of a wide fissure probably caused by a cave in. There was an 



