  After G. N. Lewis (1875-1946) proposed the term "photon" in 1926, many
physicists adopted it as a more apt name for Einstein's light quantum. However,
Lewis' photon was a concept of a very different kind, something few physicists
knew or cared about. It turns out that Lewis' name was not quite the neologism
that it has usually been assumed to be. The same name was proposed or used
earlier, apparently independently, by at least four scientists. Three of the
four early proposals were related to physiology or visual perception, and only
one to quantum physics. Priority belongs to the American physicist and
psychologist L. T. Troland (1889-1932), who coined the word in 1916, and five
years later it was independently introduced by the Irish physicist J. Joly
(1857-1933). Then in 1925 a French physiologist, Rene Wurmser (1890-1993),
wrote about the photon, and in July 1926 his compatriot, the physicist F.
Wolfers (ca. 1890-1971), did the same in the context of optical physics. None
of the four pre-Lewis versions of "photon" was well known and they were soon
forgotten.
