As a child, Joseph Priestley noticed something that would influence the rest of his life: If you keep a bug in a jar for too long, it will die. At the time Joseph Priestley didn’t understand why that was true—nobody did. No one really studied the air; it was something everyone took for granted.

There once was an inquisitive, thoughtful girl named May. She was born in Belgium, about 100 years ago. She lived there only a few years until the German invasion in 1914. Fleeing Europe, May Sarton and her family came to live in Cambridge, Massachusetts, where May’s father became a professor.