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



SUMMARY AND DISCUSSION OF RESULTS. 



1. The highest temperature measured was 432° C. This, 

 (No. 33), was found in a small and relatively inconspicuous 

 crack which one would have expected to be cooler than great 

 volcanoes like No. 32, in which the center of the steam column 

 was inaccessible to our instruments. 



2. We measured 102 vents with temperatures above 100° C. 

 in the 48 areas which we visited and located. Nine vents with 

 temperatures between 390° and 440° C. were measured ; 28 vents 

 between 290° and 390° C. ; 49 vents between 190° and 290° C. ; 

 16 vents between 100° and 190° C. ; together with many hundred 

 measured but not recorded, with steam at the boiling point. 

 The relatively small number of vents between 100° and 190° C. 

 is to be interpreted as due to the difficulty of working the 

 thermocouple between these temperatures, because of short 

 circuiting by condensing steam. 



3. The temperatures of a number of chimney-like vents 

 were distinctly highest at the surface of the ground where the 

 hot gases met the air. The greatest difference was observed 

 in No. 23, which was 107° C. hotter at the surface than three feet 

 down the hole, the temperatures being — surface, 352° C. • three 

 feet down, 245° C. Such diflerences were observed in Nos. 3, 

 4, 5, 9, 11 and 23. 



This increase of temperature at the surface is interesting in 

 view of the fact that the opposite was expected, (a) Since the 

 gas presumably issues from a molten magma beneath the 

 surface, one would expect a steaily lowering of the tempterature 

 gradient from the hot magma t> > the cold air. (b) Since the 

 gas issues under considerable pn-ssure, roaring and hissing as 

 it rushes out of the orifice, its expansion if carried out adiobati- 

 cally would considerably lower the temperature. 



While it would be easy to hypothecate reactions of gases 

 that would liberate heat enough to produce the observed rise 

 in temperature, such a speculation could have little value until 

 the gases can be examined chemically. The analyses now under 

 way and projected by the Geophysical Laboratory of the 

 Carnegie Institution ought to throw much light on this ques- 

 tion. 



