The interaction of charcoal and ammonia in solution or gaseous phase appears to involve two distinct dissimilar reactions. The first one is a neutralising reaction involving the acidic CO2-complex in the char coal. The magnitude of this reaction depends on the condition of the experiment. The ammonia adsorbed can be recovered completely on hydrolysis with Mel or on boiling with NaOH. The second one involves fixation of nitrogen in a non-hydrolysable form .It appears to be of active Led type, but cannot be attributed to any surface group that has been postulated so far.