633.    COWARD, H. F., AND WILSON, S. P.  Equilibrium in the System Carbon, Hydrogen, and Methane.  Jour. Chem. Soc., vol. 115, 1919, pp. 1380-1387, Chem. Abs., vol. 14, 1920, p. 1521.

      Synthesis of CH₄ from its elements was achieved by Bone and Jerdan (abs. 296) and confirmed by Bone and Coward (abs. 293); the decomposition of CH₄ into C and H₂ was demonstrated by Bone and Coward (abs. 294).  Equilibrium in the system C+2H₂=CH₄ at 1,000°-1,200° showed that the mixture contained approximately 1% of CH₄.  The present experiments were carried out in the apparatus described by Bone and Coward, the gaseous products being passed several times through the heated porcelain tube until analysis indicated that equilibrium was reached.  The % compositions of the equilibrium mixtures of CH₄ and H₂ were respectively:  At 1,100°, 0.6 and 99.4; at 1,000°, 1.1 and 98.9; at 850°, 2.5 and 97.5  Calculation of the heat of combustion of CH₄ from the experimental values, using the integrated form of the equation d log K/dT=-Q/RT², gives 18,000 cal., with a possible error of 2,000 cal.  Equilibrium was reached both by synthesis and decomposition.  The use of Ni or Pt as catalyst was advantageous at the lower temperatures, the gases showing practically constant composition after the 2d passage.  A steady production of CO was noted, due to a side reaction between H₂O vapor and C.