 Complete the following phrase:  By 1909, the bell had made six trips, and not only had the cracking become worse, but souvenir hunters had deprived it of over one percent of its weight. Its weight was reported as in 1904. When, in 1912, the organizers of the Panama-Pacific International Exposition requested the bell for the 1915 fair in San Francisco, the city was reluctant to let it travel again. The city finally decided to let it go as the bell had never been west of St. Louis, and it was a chance to bring it to millions who might never see it otherwise. However, in 1914, fearing that the cracks might lengthen during the long train ride, the city installed a metal support structure inside the bell, generally called the spider. In February 1915, the bell was tapped gently with wooden mallets to produce sounds that were transmitted to the fair as the signal to open it, a transmission that also inaugurated transcontinental telephone service. Some five million Americans saw the bell on its train journey west. It is estimated that nearly two million kissed it at the fair, with an uncounted number viewing it. The bell was taken on a different route on its way home; again, five million saw it on the return journey. Since the bell returned to Philadelphia, it has been moved out of doors only five times: three times for patriotic observances during and after World War I, and twice as the bell occupied new homes in 1976 and 2003. Chicago and San Francisco had obtained its presence after presenting petitions signed by hundreds of thousands of children. Chicago tried again, with a petition signed by 3.4 million schoolchildren, for the 1933 