THE 



POPULAR SCIENCE 



MON^THLY. 



CONDUCTED BY E. L. AND W. J, YOUMANS. 



VOL. XVIII. 



NOVEMBER, 1880, TO APRIL, 1881. 



NEW YORK : 



D. APPLETON AND COMPANY, 



1, 3, AND 5 BOND STREET. 



1881. 



