590 DAY AND SHEPHERD WATER AND VOLCANIC ACTIVITY 



is altogether inconceivable that any such quantity of uncombined hydro- 

 gen is available in the emanation from the volcano. For if we were to 

 assume that as much as 1,000 liters of volcanic gas (which is a very 

 liberal estimate) passed into the collecting train in the 15 minutes during 

 which the pumping was continued, such a quantity of free hydrogen (375 

 liters) would be equivalent to 40 per cent of the total composition, a 

 quantity sufficient to form an explosive mixture, on contact with air, of 

 such extreme violence as to change the entire character of the volcanic 

 activity at Halemaumau. It is a fact of general observation that the 

 bubbles of gas which come up through the liquid lava, even when they 

 reach the enormous size of 30 feet in diameter, give no explosion what- 

 soever. 



We may therefore fairly conclude, both from the character of the reac- 

 tions in which the iron might have a part and from the quantity of water 

 collected, that the presence of the iron tube has no considerable signifi- 

 cance in relation either to the character or to the amount of volatile 

 material collected. 



The Reaction between H 2 and S0 2 or C0 2 



To this reaction assumed to be going on between H 2 and FeO may be 

 added another and much more important one in which the iron has no 

 part. The free hydrogen set free by the volcano reacts with sulphur 

 dioxide at 1,000° to give water and free sulphur directly. It will also be 

 recalled that carbon dioxide and hydrogen undergo similar reaction at 

 this temperature. This is the familiar water-gas reaction 



H 2 + C0 2 JtS CO + H 2 



which has been thoroughly studied by Haber 14 and others throughout the 

 entire range of temperatures found to prevail at this volcano, and may be 

 accepted without limitation as an important factor in the activity which 

 we are studying. It follows directly from this that the chemical analyses 

 of volcano gases offered by Brim in support of his conclusion that the 

 exhalations from Kilauea and other volcanoes are anhydrous, also carry 

 on their face the clear proof that his conclusion is untenable. Neither 

 C0 2 nor S0 2 can be associated with free hydrogen at temperatures in the 

 vicinity of 1,000° without the formation of water. The two analyses 

 offered by Brun of the gases given off on reheating the Kilauea lava show 



14 See, for example, P. Haber : "Thermodynamik Technischer Gasreactionen," p. 158. 

 MUnchen, 1905. 



