Metaphor for independence
In the first chapter, the author mentions the bicycles craze that affected the nation. More and more people were becoming avid cyclists, spending days on excursions on their bicycles. However, not everyone saw them as a good thing. There were some who were concerned that bicycles offered the population too much freedom since now they had the possibility of traveling and going away from home much further than they would have been able if they were on foot. Because of this, the bicycle became a metaphor for freedom and independence and because of this the conservative population was against them.
Business and warfare
In the first chapter, Wilbur talks about the businesses he was involved and how he felt about being a businessman. In one of his letters, he compares being involved in a business with being involved in warfare. The comparison shows just how little Wilbur wanted to be involved in the business world and how much he resented the life he had.
Riding a bicycle and flying
The Wright brothers had a bicycle business before they became interested in flying and they even came up with a design of their own for a better bicycle. When they became interested in building flying machines and gliders, they compared the equilibrium needed in a bicycle with the equilibrium a glider would need to fly. The comparison also makes the reader understand that every problem, no matter how big it seems, can be broken down into smaller pieces and then reconstructed in a simpler way. This also shows how ingenious the brothers were, applying the knowledge they had to something entirely new.
Metaphor for the dangers of flying
In order to test the new glider, Wilbur had to travel to a place named Kitty Hawk. When Wilbur reached a city near the place where he was supposed to get a boat to Kitty Hawk, he meet with a sailor who offered to take him there, the journey to Kitty Hawk was extremely dangerous and it lasted two days, time during which the people on the boat had to fight against harsh conditions. The journey to Kitty Hawk is used here as a metaphor to make reference to the dangerous journey the brother embarked on and to suggest the dangers they will have to face on their quest to fly.