ESTABLISHED BY EDWARD L. YOUMANS. 



THE 



POPULAE SCIENCE 



MOE'THLY. 



EDITED BY WILLIAM J. YOUMANS. 



VOL. XXXIII. 



MAY TO OCTOBER, 1888. 



NEW YORK : 



D. APPLETON AND COMPANY, 



1, 3, AND 5 BOND STREET. 



1888. 



