28 



Kilaiii'ii ami Maioia Lmi. 



Keanakakoi, for fort_y-five years and have seen little change.'' The cloud which often, 

 but not always hangs over the active pit is the steam condensed by the cold winds 

 from Mauna Loa ten thousand feet above it, and as steam has been thought the main 

 factor in the rise of lava in the craters, it should be noticed how small the suppl^^ of 

 steam in the active outpour of Kilauea really is. While the heat would of course 

 render the aqueous vapor invisible directly in or over the pit, that very heat drives the 

 steam up into the cold regions, and it Avould be seen as cloud, or pour down as rain if 

 abundant, but neither effect is always produced at times of greatest activity, and when 



Fig. 26. KILAUKA WITH SO-CALLED SJIOKK FROM HAI.KMAUMAU. 



the pit is empty of molten lava the smoke is often most abundant (Fig. 26). Next to 

 steam sulphurous acid (H^SO,) is abundant, and so far as ni}' experience goes is always 

 present: this drj- vapor is pungent and in passing through a stream of it one must 

 hold his breath. This gas is often so abundant as to prevent travel around the lee 

 side of the pit, sometimes even of the main crater. Hydrogen, supposed to be the 

 result of the decomposition of water by great heat, is often present and its combustion 

 is seen in the flames that play around the cracks or, as in 18S0, rise in considerable 



"The late Will. Lowtliian Green in his valuable "\'estiges of the Molten Globe," II, p. 75, writes: "It has 

 sometimes been said that the large quantities ui pure aqiifous vapor often noticed in and about Kilauea, shows that it 

 is steam, or the vapor of water, which produces the appearance of 'eljulition' in the lava lakes. We venture to sug- 

 jfest that any vapor of water which had Ijccn intimately mixed or 'boiled up' with the white-hot molten lavas of the 

 Kilauea lakes, could never again appear at the surface as pure steam. It would be partially decompo.sed, and unmis- 

 takably tainted with sulphuretted hydrogen. Kven the moist air which escapes would be so tainted. There is an 

 evident source for all the pure steam found about Kilauea in the rain and the surface waters that get to the hot rocks: 

 but they must be less hot than incandescent : or else the proportion of water to molten lava must be sufficiently great 

 to reduce the temperature below a full red heat." 



[406] 



