THE

POPULAR SCIENCE

MONTHLY.

CONDUCTED BY E. L. YOUMANS.

VOL. IV.

NOVEMBER, 1873, TO APRIL, 1874.

NEW YORK:

D. APPLETON AND COMPANY,

549 & 551 BROADWAY.

1874.

ENTERED, according to Act of Congress, in the year 1874, BY D. APPLETON & CO.,

In the Office of the Librarian of Congress, at Washington.