THE POPULAR SCIENCE MONTHLY
Reading edition
EDITED BY J. McKEEN CATTELL
VOL. LVII MAY TO OCTOBER, 1900
NEW YORK AND LONDON McCLURE, PHILLIPS AND COMPANY 1900
Copyright, 1900, By McCLURE, PHILLIPS AND COMPANY.
PROFESSOR WOLCOTT GIBBS,
President of the National Academy of Sciences, Emeritus Rumford Professor and Lecturer on the Applications of Science to the Useful Arts at Harvard University.