"For the reaction of nitrogen atoms with molecular oxygen, the nitrogen and oxygen atom concentrations were estimated, at different temperatures and pressures, by addition of excess N0 and measurement of N2O and NO produced. The rate constant was given by 2.3 x 10^12 exp(-5,900/RT) cc mole^-1 sec^-1. The maximum production of oxygen atoms was found to correspond to the maximum amount of HCN produced in the active nitrogen-ethylene reaction. A rate constant of 1.83(+- 0.2) x 10^15 cc^2 mole^-2 sec^-1 was determined for the reaction of nitrogen atoms with oxygen atoms, in the absence of molecular oxygen, at pressures of 3, 3.5 and 4 mm, in an unheated reaction tube. The nitrogen atom consumption was estimated by titrating active nitrogen with NO at different positions along the reaction tube. Using the same titration method, the rate constant for the decay of nitrogen atoms, in an unheated vessel, was found to have the value of 5.2 x 10^15 cc^2 mole^-2 sec^-1, with y= 7.5 (-+ 0.6) x 10^-5, in the pressure range from 0.5 to 4 mm. Under similar conditions, and by similar methods, a value of 4.87(+- 0.8) x 10^14 cc^2 mole^-2 sec^-l was obtained for the rate constant of the reaction between nitrogen atoms and hydrogen atoms, over the pressure range from 2.5 mm to 4.5 mm." --