ANALYSES OF GASES 595 



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

 which is now present as water, if it came from the air, must have left be- 

 hind 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 number 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 instead of 74 cubic centimeters, 

 as actually found. There is but one conclusion, namely, that only the 

 minor portion of the water found in the tubes was formed through reac- 

 tion with atmospheric oxygen. Here again, therefore, we have corrobo- 

 rative evidence of water emanating directly from the liquid lava. 



None of these vacuum tubes gave a test for ammonia, which is not sur- 

 prising, since the water collected in May showed only a trifling amount. 

 With the possible exception of 5 milligrams of insoluble residue found in 

 tube number 1 of the May collection, no titanium was present. The other 

 tubes of the series yielded none on test. 



The Hot Emanations from Cracks about the Halemaumau Crater 



It was thought desirable to collect and analyze the gases from a number 

 of the hot cracks which occur outside the rim of the Halemaumau pit 

 (see plate 17) for comparison with the gases exhaled from the liquid lava. 

 One of the cracks forms an almost complete ring around the pit at a dis- 

 tance of about 150 meters from the rim. While this crack appears prac- 

 tically continuous, there are a number of points where the gaseous exhala- 

 tions are much more voluminous than at others. The small steam cloud 

 in plate 17 comes from this crack. The temperature of the gases ob- 

 tained at points on this circular crack and some 10 feet below the surface 

 were quite uniformly between 190 and 200°. 



At the most noticeable of these "hot spots," locally known as the 

 "Devil's Kitchen" or "Postcard Crack," and situated northeast of the 

 Halemaumau pit, the surface lava flows are much decomposed and con- 

 sist of a coarse, somewhat sandy, mixture of calcium sulphate, alum, ferric 

 sulphate, and much free sulphur. In the gaseous exhalation the amount 

 of S0 3 occurring as such is relatively high, while C0 2 , S0 2 , and free sul- 

 phur are also present in large quantities. A vacuum tube filled at this 

 point yielded in weight per cents : 



C0 2 3.64 (per cent by weight) 



2 19.54 " " " 



N 2 6G.71 " " " 



H 2 9.74 " " " 



SO a 18 0.37 " " " 



"The total sulphur computed as S0 8 , 



