CHEMICAL REACTIONS 591 



them to be chiefly made up of precisely these ingredients (loc. cit., page 



115) : 



Brim's Analyses of Gases obtained from Kilauea Lava when Heated in Vacuo 



1 2 



HC1 .traces CI (libre) 5.58 



S0 2 1.7 HC1 1.71 



C0 2 50.8 , S0 2 4.72 



CO .'..... 17.3 Cb 2 69.09 



H 2 28.5 CO 11.60 



N 2 1.2 CH 4 0.83 



H 2 6.10 



, N a 0.3 



It is, furthermore, noticeable that the analyses here offered by Brun as 

 representative of the gases emanating from Halemaumau do not in any 

 way agree with the composition of the gas which we obtained from liquid 

 lava. He finds, for example, in one analysis more than 7 per cent of 

 chlorine in one form or another, where we find 0.02 per cent or less. He 

 obtained about 5 per cent of S0 2 , whereas S0 2 during our visit was per- 

 haps the most notable gas evolved from this crater. 



The relative Quantities of the constituent Gases 



Leaving now the question of ,the identity of the gases discharged by 

 the lava at Halemaumau, we should perhaps turn for a moment to the 

 consideration of their relative quantity, which, as already intimated, is 

 not so well established by our samples because of the unexpected presence 

 and condensation of the water in the collecting tubes. 



In addition to the presence of the iron tube and its possible effect on 

 the total quantity of water and of free sulphur collected in our tubes, 

 which has been discussed above, our analyses of the gases (page 588) are 

 subject to a second limitation which is at once obvious. When the pump- 

 ing had been completed, the collecting tubes each contained a quantity of 

 the condensed water, in which the fixed gases are. individually soluble iu 

 varying degree both during and after cooling. There is also some reac- 

 tion between the gases and water. The Jong period which elapsed be- 

 tween the date of collecting the gases and their analysis in Washington 

 after the close of the field season (nearly a year) gave opportunity fox 

 these readjustments to proceed practically to completion. The SO... for 

 example, has gone over in pari or altogether to SO a and gone into solu- 

 tion, and only two of Mk 1 five tubes analyzed now show SO a as such, 

 Moreover, the resulting acid solution ma\ have reacted to a limited ex- 

 tent on the glass tube, and accordingly be responsible for all or a part o( 

 the alkalies, lime, and almuina shown in the analyses of the water (page 

 692). 



