The Modern Occult 449
Birds As Flying Machines 473
Electric Automobiles 479
The Human Body As an Engine 491
Chapters on the Stars 500
The Psychology of Red. (II.) 517
The Expenditure of the Working Classes 527
The Conquest of the Tropics 540
Discussion and Correspondence 546
Scientific Literature 550
The Progress of Science 555
THE
POPULAR SCIENCE
MONTHLY
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.