THE

POPULAR SCIENCE

MONTHLY.

EDITED BY WILLIAM JAY YOUMANS.

VOL. XL.

NOVEMBER, 1891, TO APRIL, 1892.

NEW YORK:

D. APPLETON AND COMPANY,

1, 3, AND 5 BOND STREET.

1892.

75,439

COPYRIGHT, 1892,

BY D. APPLETON AND COMPANY.