The Motor Boys in The Army
is the 19th volume in the series. It was published sometime during 1918. War looks likely, so it should come as no surprise that the boys don't hesitate a second signing up. Well, Bob hesitates a bit, but it's not because he's scared or doesn't believe in the war. In fact, World War I began July 18, 1914, and ended November 11, 1918. This means that if the war wasn't over when Young was writing the book, it's outcome was almost certain, since the U.S. entered the conflict April 6, 1917, and shortly thereafter, American soldiers began arriving on the Western Front in Europe and joined the battle at the rate of 10,000 per day. This infusion of additional fighting men was the major reason the balance quickly shifted to the Allied side of the conflict. The boys enter the fray in the next volume.