Dec., 1918] Are the Ten Thousand Smokts.Rzal^jtfmnojes? 101 



BIG VENTS NOT DUE TO DIFFUSE SURFACE EVAPORATION. 



But such diffuse evaporation could not give rise to the great 

 Smokes which give the Valley its character, for in these vents 

 the production of steam is highly concentrated into small areas, 

 where it bursts forth under pressure. To supply sufficient 

 steam for the production of any one of these larger vents would 

 require all the water of a good sized brook, but nowhere can any 

 stream be found which goes up in steam all at once at a par- 

 ticular point. There are several places where a stream runs 

 close beside a good sized vent.. In a few places the steam was 

 actually seen boiling up through cold water. But it appears 

 evident on inspection of such places that the steam is quite 

 independent of the brook, which merely happens to run over 

 the orifice by which it finds exit. The brook is not sensibly 

 smaller below such a place. Its temperature is not even 

 measurably altered by the proximity to the hot vapor. (See 

 page 102). 



But places where watercourses cross lines of activity are 

 uncommon. For the most part, the position of the vents 

 bears no apparent relation to the streams, but follows a pattern 

 of its own. The waters, seeking their level under gravity, 

 course down through the middle of the Valley. But a great 

 number of the largest vents come out of the marginal fissures 

 which encircle the Valley about 200 feet above its floor. 

 Throughout the Valley the vents are more prevalent along the 

 crests of ridges than in hollows where water would collect. 

 Many of the largest vents are thus located in situations where 

 any great supply of surface water would appear most improbable. 



DO THE SMOKES COME FROM VAPORIZATION OF GROUND 



WATER? 



Such soundings as we were able to make in the throats of 

 the vents confirm the view that they are more deep-seated than 

 the surface drainage, for we could find no bottom with a 

 stone tied to a hundred foot rope. This made it at once clear 

 that they could not be formed by the vaporization of the surface 

 streams. Perhaps they may come from the vaporization of 

 subterranean streams which encounter a hot lava flow at some 

 depth below the present surface. This supposition, it must 

 be admitted, is wholly hypothetical since there is not otherwise 



