Charles Barkla was one of the first scientists to help reveal the true nature of X-rays and, through later applications of his findings, the nature of the atom. He was born and educated in Liverpool, England, and received his bachelor's in physics from the University of Liverpool in 1898. From there he went to Trinity College, Cambridge, where he researched under Joseph J. Thomson, who had done significant work with cathode rays. Although Thomson would have tremendous influence on the direction of his work, Barkla remained at Cambridge solely for the chance to sing in its prestigious choir (he was a talented baritone and a popular soloist). In 1902 he transferred back to Liverpool, completing his doctoral studies in 1904.

During his college years, Barkla became interested in the phenomenon of X-rays, discovered by Wilhelm Röntgen. At the time, scientists were uncertain about the nature of these rays: were...