This page has been validated.
THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXXXI
JULY TO DECEMBER, 1912
NEW YORK
THE SCIENCE PRESS
1912
THE
POPULAR SCIENCE
MONTHLY
EDITED BY
J. McKEEN CATTELL
VOL. LXXXI
JULY TO DECEMBER, 1912
NEW YORK
THE SCIENCE PRESS
1912