Absorbent powers of charcoal.

Harper's new monthly magazine 258, 1871

Dr. Hermann Vohl, of Cologne, has lately published an elaborate paper in the Archiv der Pharmacie, upon the absorbent power of charcoal and its application for disindectant and deodorizing purposes, replete with suggestions of great importance.

Among other deductions from his experiments, he states that the carbonic acid gas obtained by heating charcoal is not derived from the coal itself, but has been absorbed from the atmosphere, and is held with such tenacity that it can not be driven out by boiling in water, but that a temperature much below that of ignition is sufficient to expel it. The conclusion is the same as that whichhad been reached by another experimenter, to which we have previously made reference. Among other facts proving this statement, Dr. Vohl remarks that when charcoal has been once freed from its carbonic acid and saturated with pure oxygen, no trace of carbonic acid is appreciable, even when heated to a temperature of 690° Fahr.