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THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXXX
JANUARY TO JUNE, 1912
NEW YORK
THE SCIENCE PRESS
1912
THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXXX
JANUARY TO JUNE, 1912
NEW YORK
THE SCIENCE PRESS
1912