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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1913. 



THE GASES COLLECTED IN DECEMBER, 1912. 



From the gases which were collected in vacuum tubes on December 

 4, 1912, much less information is obtainable than from the May col- 

 lection, in spite of the more elaborate preparations made for the 

 second attempt. This was wholly due to the fact already mentioned, 

 that the dome from which the December gases were collected proved 

 on near approach to be an imperfect one, which permitted the en- 

 trance of air and a partial combustion of the gases within the dome. 

 Six individual vacuum tubes (two of one-half liter capacity and four 

 of 250 cubic centimeters) were automatically filled and sealed off 

 within this dome and were brought to Washington in safety, but 

 were found on opening to contain mixtures of volcano gases and air, 

 such as might be expected from exposure to the temperature at which 

 they were collected (about 1,000°). There is, of course, no more rea- 

 son for expecting the chemical reaction between the gases and air to 

 have proceeded to an equilibrium than in the case of the reactions 

 between the volcanic gases alone, whence the analyses of the gases 

 contained in these tubes may be expected to show very variable 

 proportions. 



In stating the analyses the free oxygen found has been subtracted, 

 together with a corresponding portion of the nitrogen appropriate to 

 the normal composition of air. Probably more of the nitrogen should 

 Jiave been subtracted as an equivalent for the oxygen taken up in the 

 combustion of the sulphur products and carbon monoxide, but the 

 amount would be difficult to fix in view of the reactions between the 

 volcano gases themselves and it has not been attempted. The analyses 

 at best add but little to the knowledge alreadv obtained. 



Table 4. — Analyses of gases collected in December, 1912. 

 [Percentages by weight.] 



If we make the only available assumption, namely, that the oxygen 

 which is now present as Avater, if it came from the air, must have left 

 behind a corresponding amount of nitrogen, then the amount of 

 nitrogen found in these three vacuum tubes is in every case two or 

 three times too small. For example, in tube No. 2, if all the oxygen 

 now contained in the water came from admixed air, there should 

 have been at least 240 cubic centimeters of nitrogen in this tube 



