iv PREFACE 



shall be simple, interesting, and instructive, yet losing 

 nothing of its accuracy. 



The proof has been read by Professor G. F. Hull of 

 Dartmouth College, for whose critical suggestions the 

 author is very grateful. Several corporations and firms 

 have kindly furnished photographs for the engravings as 

 follows : General Electric Company, the dynamo ; H. K. 

 Porter Company, Pittsburg, Pennsylvania, the air loco- 

 motive ; Baldwin Locomotive Works, the steam locomo- 

 tive ; Illinois Steel Company, the blast furnace ; Cunard 

 Steamship Company, the steamship. 



LOTHROP D. HIGGINS 



CLINTON, CONNECTICUT 

 August, 1905 



