Reinvestigation of the active nitrogen – methane reaction in the temperature range 45° to 500 °C. has confirmed hydrogen cyanide as the only product, other than hydrogen, formed in measurable amounts. An “induction” effect in the hydrogen cyanide production was observed with increase of methane flow rate. This induction decreased with increase of temperature and was shown to be due to concomitant hydrogen atom reactions, since it could be eliminated by addition of hydrogen atoms to the reaction mixture. Reinvestigation of the active nitrogen – ethane reaction over the temperature range −100° to 475 °C. also confirmed hydrogen cyanide to be the only measurable product, other than hydrogen, of that reaction. There was some indication that an induction effect was present with ethane, as with methane, and it may be concluded tentatively that both reactions are carried substantially by hydrogen atom reactions.