Something unusual about the Liberty Bell is that its composition is uncertain. In fact, two different analyses of the metallic composition of the Liberty Bell came back with considerably different results, as far as percentages. The Franklin Institute took samples in 1960, while the Winterthur Museum and the DuPont Company did their own analysis in 1975.
In general, though, the bell is roughly 70% copper and 25% tin. Other metals, in amounts between trace amounts and five percent, depending on which analysis you read, include nickel, gold, arsenic, antimony, silver, iron, zinc and lead.
The original weight of the bell was 2,080 pounds — 44.5 of that was just the bell's clapper. The bell measures 12 feet around at the lip (the bottom), and 7-1/2 feet around at the crown.
The most famous measurement on the Liberty Bell may be the length of the crack. The first crack, that was widened as part of an effort to stabilize the bell, measures 2'4" while the hairline crack that later formed, and sent the Liberty Bell into retirement, measures 2' 1/2".
You may not know that the Liberty Bell was not designed to call Philadelphians to hear the first reading of the Declaration of Independence, although that is the tradition most commonly associated with it. The Pennsylvania Assembly actually commissioned the bell in 1751 to celebrate the fiftieth anniversary of William Penn's Charter of Privileges, the original constitution in Pennsylvania. Some of the more innovative provisions included freedom of religion, democratic development of laws, and civil treatment of the Native Americans.
Quotations on the bell include Leviticus 25:10 ("Proclaim liberty throughout all the land unto all the inhabitants thereof"), and the original order of the bell by the Pennsylvania Assembly.
So what about the crack? While there is not one agreed date of the formation of the original crack, the last fracture appeared when the bell was ringing in honor of President Washington's Birthday in 1846. According to a story in the Philadelphia Public Ledger, the bell "appeared to be in excellent condition until noon, when it received a sort of compound fracture in a zigzag direction through one of its sides which…let it a mere wreck of what it was."
Other facts about the Liberty Bell pertain to the changing significance it has had during American history. Before the fatal cracks silenced the bell, it was used frequently — it would signal the start of meetings of the Pennsylvania Assembly and call the town together for announcements. Also, it rang for special events, such as the coronation of England's King George III in 1761 and brought the citizens together to talk about Parliament's passage of the Sugar Act (1764) and the Stamp Act (1765).
In fact, the bell rang so often that the people who lived near the State House filed a petition about how they were "incommoded and distressed" by the "ringing of the great Bell in the steeple."
Even after the bell rang its last in 1846, though, it was a powerful symbol for Americans. The New York Anti-Slavery Society used it in an issue of its periodical Liberty. In fact, before this time, it had only been known as the "State House Bell." It was a Boston abolitionist who first called it the "Liberty Bell."
After the Civil War, the Liberty Bell was sent around the country as a symbol of a nation healing from warring against itself. In 1915, it went to the World's Fair in San Francisco. In 1915, a replica was constructed to rally the cause of women's suffrage and, when the 19th Amendment was ratified, granting women the right to vote, this replica was hung in Independence Hall and rung in celebration.