Final answer:
August and Jack Will laugh hysterically because of a humorous incident with a teacher, which often serves as a moment of levity and bonding in literature.
Step-by-step explanation:
August and Jack Will laugh hysterically at the end of this particular chapter due to a humorous incident with a teacher. While the exact details may vary depending on the chapter being referenced, often in literature, characters may find laughter in unexpected situations that involve authority figures such as teachers. These incidents usually break the monotony of daily routine or create a shared moment of levity, strengthening bonds between characters.