Active Nitrogen

IN the “Research Items” in NATURE for September 18, reference is made to the paper by Willey and Rideal in the Journal of the Chemical Society for July, in which the energy of active nitrogen is found to be 42,500 cal. per gm. mol. Now Strutt's photographs of the glow produced when active nitrogen acts upon iodine show that the iodine line 2061 Å.U. is produced, and this needs an amount of energy of at least 150,000 cal. It is unlikely that a series of successive impacts could give to the iodine a higher level of energy than that possessed by the nitrogen, or that simultaneous collisions of the iodine with more than one nitrogen molecule would suffice. The nitrogen glow is destroyed by iodine vapour in an exceedingly small fraction of a second, which indicates the probability of exchange of energy taking place directly between the active nitrogen molecule (if it is the molecule and not the atom) and the molecule of iodine.