The Adventures of Tom Sawyer by Mark Twain Chapter 10 Page 18

heavier woes and wholly dead to trifles.

Then he betook himself to his seat, rested his elbows on his desk and his jaws in his hands, and stared at the wall with the stony stare of suffering that has reached the limit and can no further go. His elbow was pressing against some hard substance. After a long time he slowly and sadly changed his position, and took up this object with a sigh. It was in a paper. He unrolled it. A long, lingering, colossal sigh followed, and his heart broke. It was his brass andiron knob!

This final feather broke the camel’s back.