As tradition, the bell was rung on every July 4 and on every state occasion until 1846. While not everyone agrees on when the first crack appeared on the Liberty Bell, by 1846 a thin crack began to affect its sound. In order to repair the bell, a slot was carved along the length of the crack that prevented the two sides of the bell from vibrating against each other. Two rivets were inserted in this slot to control the vibration of the two sides, and restored the bell's tonal quality.
