Note 223 — Chapter XII

At the request of the British Association, a committee undertook the investigation of this subject. Experiments were carried on by Dr. Daubeny, in the Botanic Gardens at Oxford, and by the Author, at his residence, Stockwell. Dr. Daubeny, in his report made at the meeting of the British Association at Birmingham, appears disposed to consider ten per cent. of carbonic acid in excess as destructive to the growth of ferns. I found, however, that, by gradually increasing the quantity, the ferns would live in an atmosphere still more highly charged with carbonic acid.