STATES OF THE GASES. 



37 



TABLE 25. 



Carbon dioxide thus appeared first, constituting 93 per cent of the gas 

 evolved at 360 C., while hydrogen was not present in a measurable quan- 

 tity. On the other hand, at the highest temperature used (850) hydrogen 

 amounted to 95 per cent of the total and carbon dioxide was entirely 

 wanting. The steady decrease in the proportion of carbon dioxide with 

 the elevation of the temperature, and the proportionate increase in the 

 value of the hydrogen, are striking. The minor constituents, carbon 

 monoxide and methane, underwent some variations, but did not change 

 so radically. The former came off at the lower temperature, but declined at 

 full red heat. Nitrogen, it appears from other experiments, does not appear 

 in the gases obtained by moderate heating, but increases steadily in impor- 

 tance when the heat is carried higher. It is the last gas to be liberated. 



The complete table, expressing the volumes of each gas per unit volume 



of gneiss, follows: 



TABLE 26. 



These results are graphically represented in the curves of figure 1. 



The fact that little gas could be obtained below 450 is in itself a strong 

 argument against the hypothesis that the gases come from pores, and 

 there also seems no way in which the behavior of the gases, as set forth by 

 these curves, can be consistently fitted into that theory. 



TESTIMONY OF THE METEORITES. 



Meteorites have already been subjected to investigation of this sort, 

 though not with this purpose in mind. Mallet divided the gas which he 

 extracted from the meteoric iron of Augusta County, Virginia, into three 

 portions; 1 his results have been reduced by Wright 2 to the figures given 

 in table 27: 



Mallet, Proc. Roy. Soc., vol. 20, p. 367. 2 Wright, Am. Jour. Sci., vol. 2 ; p. 261. 



