<P> Today, the Liberty Bell weighs 2,080 pounds (940 kg). Its metal is 70% copper and 25% tin, with the remainder consisting of lead, zinc, arsenic, gold and silver . It hangs from what is believed to be its original yoke, made from American elm . While the crack in the bell appears to end at the abbreviation "Philad" in the last line of the inscription, that is merely the 19th century widened crack which was filed out in the hopes of allowing the bell to continue to ring; a hairline crack, extending through the bell to the inside continues generally right and gradually moving to the top of the bell, through the word "and" in "Pass and Stow," then through the word "the" before the word "Assembly" in the second line of text, and through the letters "rty" in the word "Liberty" in the first line . The crack ends near the attachment with the yoke . </P> <P> Professor Constance M. Greiff, in her book tracing the history of Independence National Historical Park, wrote of the Liberty Bell: </P> <P> (T) he Liberty Bell is the most venerated object in the park, a national icon . It is not as beautiful as some other things that were in Independence Hall in those momentous days two hundred years ago, and it is irreparably damaged . Perhaps that is part of its almost mystical appeal . Like our democracy it is fragile and imperfect, but it has weathered threats, and it has endured . </P> <P> In addition to the replicas which are seen at Independence National Historical Park, early replicas of the Liberty Bell include the so - called Justice Bell or Women's Liberty Bell, commissioned in 1915 by suffragists to advocate for women's suffrage . This bell had the same legend as the Liberty Bell, with two added words, "establish justice", words taken from the Preamble to the United States Constitution . It also had the clapper chained to the bell so it could not sound, symbolizing the inability of women, lacking the vote, to influence political events . The Justice Bell toured extensively to publicize the cause . After the passage of the Nineteenth Amendment (granting women the vote), the Justice Bell was brought to the front of Independence Hall on August 26, 1920, to finally sound . It remained on a platform before Independence Hall for several months before city officials required that it be taken away, and today is at the Washington Memorial Chapel at Valley Forge . </P>

When did the liberty bell crack the second time