Surface oxygen complexes on charcoal come into existence during or within a few minutes of tin formation of the charcoal, and extend themselves rapidly on exposure oxygen but, gradually on exposure to air, to the same limiting rain.. The presence of moisture has to effect. Ageing in limited supplies of air produces slow and restricted effects. The amount of complex decomposing into Co2 decreases with increase in the carbonisation temperature, while that, decomposing into CO appears to be more or less independent of the carbonisation temperature. The base-neutralising capacity of charcoal is almost equivalent to the amount of CO2 evolved on degassing the same at 1000.