COPYRIGHT, 1918, BY THE 

 MCGRAW-HILL BOOK COMPANY, INC. 



First Printing, March, 1918. 



Second Printing, November, 1918. 



Third Printing, July, 1919. 



Fourth Printing, April, 1920. 



Fifth Printing, July, 1921. 



AGfliC. PERT, 



TJIK MAl-r,K I'KKHS V <) K 1C V A. 



