391thle capacity should vary little with the pressure. This conclusion is confirmed by the result with chloropicrin reported in this investigation.The capacity per g. of charcoal was 0,2800 g. a t a pressure of approximately 5 X IO^ bars and 0.3100 g. a t 5 X xo4 bars, an increase of only 10% in acity with a Io-fold increase in pressure. The present data are, therefore, qualitatively in accordance with the one layer theory as rega.rds the author wishes to express his appreciation to Professor Prederick eyes of the Massachusetts Institute of Technology for criticisms and suggestions in connection with this work.