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THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXI
NOVEMBER, 1901, TO APRIL, 1902
NEW YORK
THE SCIENCE PRESS
1902
THE
POPULAR SCIENCE
MONTHLY
EDITED BY
VOL. LXI
NOVEMBER, 1901, TO APRIL, 1902
NEW YORK
THE SCIENCE PRESS
1902