ft I 8 



Engineering 

 Library 



COPYRIGHT 1922 

 WILLIAMS & WILKINS COMPANY 



Made in United States of America 



All rights reserved, including that of translation 



into foreign languages, including 



the Scandinavian 



COMPOSED AND PRINTED AT THE 



WAVERLY PRESS 



BY THE WILLIAMS & WILKINS COMPANT 



BALTIMORE, MD., U. S. A. 



