Character Analysis
The interesting thing about Belle Prater is that she doesn't show up in the story in person—because she's already gone by the time the book opens. But despite that, her presence (or non-presence) sets everything in motion, particularly Woodrow's arrival in Coal Station. And because of this, Belle is a fully formed and fascinating woman, even if we only get to hear about her from other characters.
A Free Spirit
Woodrow's mother, Belle, goes missing at the very beginning of the book. Even though she is married and has a child, Belle still feels like she's missing out on her real life. Woodrow remembers her often saying that she feels confined by her life, as though she's stuck in a straitjacket:
"So one day Mama was reading out loud to me about the straitjacket, and suddenly she stopped reading and said, 'I know how he feels. I am in a straitjacket, too. That's how I feel. Squeezed to death. I can't move. I can't breathe. I have to get out of here.'" (7.60)
Because she feels so constrained, Belle ends up leaving her family in order to start a new life. She leaves dressed up as a boy and runs away with the circus because she just wants to start over with a clean slate. She wants to finally have the chance to explore the world and forge a new identity—on her own terms.
Painful Past
Belle also wants to get away from her life because she's tormented by her past. She cannot remain near her family because she was deeply in love with Amos before he chose her sister over her. It just hurts her too much to see them together:
"She was so hurt… and desperate. She had to leave, not because she hated us, but because seeing me and Amos together every day was like opening up a wound over and over." (5.37)
Because Belle is heartbroken after seeing Love and Amos together, she ends up isolating herself from her family, and by the time she disappears she has become somewhat estranged from her parents and sister—not because she doesn't love them, but because it hurts her too much to see them.
If you've read up on Gypsy and Woodrow, then you know that they both overcome the hardships in their lives to make the best of what they have. Belle is an example of taking a different approach, of running away in hopes of a clean slate instead of figuring out how to make the life she's living work.