144 



F. A. Ferret — Lava Fountains of Kilauea. 



that this is constantly being evolved intermolecularly and 

 expanded upon relief of pressure, and the liquid, while still 

 heavy, acquires some of the peculiarly mobile yet momentum- 

 damping qualities of foam. A piece of rock, tumbling over 

 the talus and reaching the shore with just sufficient momen- 

 tum to topple over into the lake from a height of but a few 

 centimeters, sinks with apparently less resistance than in water 

 and the liquid closes over it without a splash. Daly's quaint 

 statement regarding the flow of pahoehoe* might well, I believe, 



Fig. 5. 



Fig. 5. Telephoto day view. "Old Faithful." Dome phase. 



be applied to this material — it " moves, as it were, on molecular 

 and vesicular ' ball-bearings \" 



As a result of this condition large gas bubbles may rise rap- 

 idly through the liquid and produce fountains, and yet escape 

 without visible commotion — excepting in the spatter phase — 

 other than the boiling movement of the dome, and, as the gas 

 is invisible, many observers have asserted its non-existence. 

 Fortunately, however, an observable phenomenon enables us to 

 prove our contention — the gas. on coming in contact with the 

 atmosphere, burns. The flames, which have frequently been 



*Op. cit.. p. 108. 



