Jaggar — Volcanologic Investigations at Kilauea. If35 



equilibrium among the gases at the surface of the lake is shown 

 by great variety in proportions of the individual gases in dif- 

 ferent tubes collected at the same time, and by increase of 

 maximum temperature in the fountains at those times when 

 the quantity of gas is greater. Discussing the water which 

 condensed abundantly in the tubes, these authors believe it 

 could not have come from reaction of hydrogen with air 

 because such a quantity of hydrogen would produce explosion. 

 But this was all on the stated assumption that the flaming 

 gases had met no atmospheric air below the surface cracks 

 where they were collected. 



Atmospheric Oxidation of Magmatic Gas. 



Without entering here upon an exhaustive discussion in 

 criticism of these several writers, I would point out that, 

 except for the statement quoted from Ferret, these investiga- 

 tors seem to me to take no sufficient account of the certain and 

 obvious reaction of the volcanic gases with oxygen of the air, 

 nor of the extent to which sulphur, hydrogen and carbon may 

 by less obvious mechanism be brought into contact with air 

 within the edifice of highly porous rock that encloses the lava 

 conduit for some thousands of feet above sea-level. Day and 

 Shepherd, however, point out that in the gas reactions there is 

 an enormous store of volcanic energy '' which reaches its 

 maximum temperature at the surface itself.""^ The abundant 

 flamesf through cracks in crusts over the lake, over the grotto 

 fountains and central fountains, through the border cones, and 

 the blowing cones which form above cracks in the floors, and 

 the myriad flaming orifices even at the fronts of some of the 

 flows (block lava of Mauna Loa 1916),:|: are the obvious evi- 

 dences of reaction between gas and air. A second method 

 of indraught of air downward into the lava is produced 

 by downflow at the grottoes, and in times of subsidence at the 

 sinkholes, when violent cascades rush down border pots from 

 the lake, the cataracts tumbling vertically 30 or 40 feet (9 or 

 12"") into a boiling, flaming and fuming cauldron (fig. 9^), car- 

 rying down the surface crusts, and obviously engulfing air 

 by downsuction as in a waterfall. A third mechanism which 

 carries air downward into the liquid lavas of lakes and flows 



*0p. cit., p. 600. 



f Dr. Wm. T. Brigham was the first to point out these flames, which were 

 never positively seen by Professor Dana, though they were eventually 

 accepted by him. {Characteristics of Volcanoes, 1891.) The insistence by 

 Brigham on flames, and by Green on absorption of air, against geological 

 opinion which would have it that steam must be the active agent, illustrates 

 the great advantage in science of continuous observation over closet theoriz- 

 ing. Brigham, Green and Coan lived on the field and knew their volcano ; 

 the foreign geologists came for short visits, intent on seeing, with precon- 

 ceived opinion for a guide. 



^Lava flow from Mauna Loa, 1916, by T. A. Jaggar, this Journal, xliii, 

 pp. 355-288, April, 1917. 



