When the moon, which was full and bright…came in her course to that space in the sky opposite my casement and looked in at me through the unveiled panes, her glorious gaze roused me. Awakening in the dead of night, I opened my eyes on her disk – silver-white and crystal clear. It was beautiful, but too solemn; I half rose and stretched my arm to draw the curtain.
Good God! What a cry!

– Charlotte Bronte

Jane Eyre, Chapter 20. Jane wakes up to the moon shining full and bright through her window. The moon appears as a warning. Its description of being “too solemn” is foreshadowing of danger ahead. Jane next hears a scream running from one end of Thornfield to the other. We will later learn that madwoman Bertha Mason has attacked her visiting half-brother Richard Mason and stabbed and bitten him.