APR 1 5 1931 wnasfiw Aao^vaa 



ft 3ki^ ho Ai^viisn 



TRANSACTIONS OF ^f^^^ 

 WAGNER FREE INSTITUTE 

 OF SCIENCE 

 OF PHILADELPHIA 



VOLUME VIII 

 JULY, 1917 



MEMORIAL VOLUME 



SPECIAL LECTURES BY THE TEACHING STAFF OF THE 



INSTITUTE: Henry Leffmann, Samuel Tobias Wagner, Spencer 



Trotter, Samuel Christian Schmucker, Leslie Birchard Seely, 



Charles Herbert LaWall, David Wilbur Horn 



WAGNER FREE INSTITUTE OF SCIENCE 



MONTGOMERY AVE. AND SEVENTEENTH ST. 



PHILADELPHIA 



