The returned volume

An original fiction passage set in the nineteenth century.

Margaret laid the repaired volume on the library table. Mr Wren turned each page, pausing at the faint stain near the back. She explained that the book had slipped from her basket in the rain and that she had dried it as carefully as she could. He continued to examine the pages without replying. With no word from him, Margaret fixed her eyes on the stain and rubbed her thumb along the seam of her glove. At last, Mr Wren closed the book and reached for his ledger.

Identify the sentence in which Margaret’s actions show her unease as she waits for Mr Wren’s verdict.