Our three lines of national defense.
Our three lines of national defense. LOC Summary: Poster showing a battleship, an industrial cityscape, and military personnel behind an American flag. LOC Notes: Title continues: The smoke of America's factory stacks is a signal of our workers' and employers' loyalty. It means more guns - more ships - more food. Our industries are the third and main supporting line of defense - our base of supplies. Without them the Army and Navy would be helpless. As good patriots let us strive to keep our industries strong. Date Created/Published: 1917. World War 1 propaganda poster provided by LOC. Original medium: 1 print (poster) : lithograph ; 63 x 47 cm.