President McKinley was shot while attending this exposition. The x-ray apparatus were on display at the Exposition, but no one thought to use it on the wounded President McKinley to locate that second elusive bullet.
Sources about Buffalo Exposition:
Official catalogue and guide book to the Pan-American Exposition with maps of exposition and illustrations, Buffalo, N.Y., U.S.A., May 1st to Nov. 1st, 1901. Buffalo: Charles Ahrhart,