78 THE GASES IN ROCKS. 



Nitrogen with an abnormal amount of inert gas (probably both argon 

 and helium) occurs, under high pressure, in a gas-well at Dexter, Kansas. 1 

 However, instead of being derived from igneous rocks, this comes from a 

 gas-bearing sand near the contact of the Permian with the Upper Carbonif- 

 erous. An analysis of this gas gave: 2 Oxygen, 0.20; methane, 15.02; 

 hydrogen, 0.80; nitrogen, 71.89; inert residue, 12.09; total, 100. 



Neither carbon dioxide nor carbon monoxide was present in this gas. 

 The methane, and perhaps the hydrogen also, may be attributed to the 

 decomposition of organic matter, since natural gas-wells exist at no great 

 distance away. But the remarkable feature of this analysis is the large 

 amount of nitrogen with the very abnormal percentage of inert gas. 

 From this analysis, and the testimony of many spring-waters which give 

 off considerable quantities of argon and helium, it would appear that 

 gases often collect underground somewhat in proportion to their chemical 

 inertness. The chemically active gases apparently are more largely retained 

 within the rocks by combination, while nitrogen, having less power to 

 unite chemically, more largely escapes from the rocks and accumulates in 

 reservoirs. Argon, still more inert than nitrogen, thus may reach such a 

 high proportion as 12 per cent. 



GENERAL RELATIONS. 



RELATIVE TO THE HYPOTHESIS OF A MOLTEN EARTH. 



These studies show that, within the range of temperature employed, 

 heat causes the expulsion of gases in whatever form they are held, and 

 that the greater the degree of heat the more quickly and completely the 

 gases are given off. There is reason to believe that this principle applies 

 to the molten state as well as to the solid condition. If it be applicable 

 to liquid lavas, it would favor the belief that a molten globe would have 

 boiled out most of its gaseous matter before solidifying. Gases near the 

 surface should escape rapidly. It might, perhaps, on first thought, be held 

 that, while much of the gas in the outer portion would be lost, that exist- 

 ing in the central part of the sphere would be retained and slowly recharge 

 the peripheral portion after a crust had formed and prevented further 

 escape; but the molten globe, by hypothesis, grew up gradually, and essen- 

 tially every part was once superficial. Even to-day, in an essentially solid 

 earth, there are movements of lava that bring up gases from unknown 

 depths, and it is reasonable to suppose that the molten sphere was stirred 

 up by still more effective convection currents which facilitated the expulsion 

 of gases and vapors, and that almost all of the gaseous material of the 

 globe would have been boiled out before solidification set in. 



The complete validity of this view depends much upon the fate of the 

 gases after they have reached the surface. If they were retained in the 

 form of a dense atmosphere, a condition of pressure-equilibrium might 

 be established between the atmosphere and the gases in the liquid earth, 

 by means of which the latter would retain some appreciable amount of 

 gas. But if, as some believe, our atmosphere is about all that the earth 



1 Haworth and McFarland, Science, vol. 21 (1905), pp. 191-193. 2 Loc. cit. 



