I seriously doubt they were _reading_ those books. If the fragments were found in the cannon barrels, they were most likely using the pages of the books for wadding to keep the cannonballs in place.
At 8 years old, I walked two miles home from the YMCA following my older cousin who was 10. At 12 years old, I crossed the Pacific on my own. At 16 I entered college. These types of charts are ridiculous. People should use their eyes, brain and the ability to talk to their children, to determine if their children can be left alone.