"At the time I selected tungstate of calcium because it was so fluorescent, I set four men to making all kinds of chemical combinations, and thus collected upward of 8000 different crystals of various chemical combinations, discovering several hundred different substances which would fluoresce to the X-ray.
"Edison, His Life and Inventions"
Frank Lewis Dyer and Thomas Commerford Martin
When the X-ray strikes this salt it makes it glow, or fluoresce, and objects held between the X-ray tube and the fluoroscope cast shadows according to the density of the parts which the X-rays penetrate.
"Master Tales of Mystery, Volume 3"
Collected and Arranged by Francis J. Reynolds
Some substances also, which fluoresce at ordinary temperatures, will phosphoresce at low temperatures.
"The Nature of Animal Light"
E. Newton Harvey