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THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXXVIII
JANUARY TO JUNE, 1911
NEW YORK
THE SCIENCE PRESS
1911
THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXXVIII
JANUARY TO JUNE, 1911
NEW YORK
THE SCIENCE PRESS
1911