Who is Mason? How does Rochester react whe he learns of his arrival? What strange incident involving mason brings Jane to Rochester's aid agani? What do all these events tell you about the relationship between Rochester and Mason?

Who is Mason? How does Rochester react whe he learns of his arrival? What strange incident involving mason brings Jane to Rochester's aid agani? What do all these events tell you about the relationship between Rochester and Mason? Answer bold questions pls :) thanks!