City of Light: The Story of Fiber Optics

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Guiding Light and
Luminous Fountains
(1841–1890)
Among the most wonderful displays, electric and visual, at
the recent French exposition were those pertaining to the
luminous fountains, which were arranged on a grand scale
and occupied a large portion of the plateau in front of the
main entrance. The chameleon-like changes of color in the
fountain water were something astonishing to behold. It
was not accomplished by the mere throwing of colored
lights upon the exterior of a spouting jet, but was due to
an interior electric illumination of the molecules of the water;
the beams of light being, so to speak, thrown into and
imprisoned within the crystal walls of the water and then
carried along with it, becoming visible by interior reflection
during the discharge of the water.
—Scientific American, December 14, 1889 1
I t is 400 kilometers (250 miles) as the crow flies from Geneva to Paris, a
leisurely day’s drive on modern highways. The train ride took a much longer
day in 1889, but to the 86-year-old Daniel Colladon that marked tremendous
progress. In 1825, he had spent four bumpy days and nights on the same
route in a horse-drawn coach on his way to study physics in the center of
European science. Paris had been called the City of Light since it became the
intellectual center of the Age of Enlightenment in the late eighteenth century. 2
Colladon made his 1889 trip to see the Universal Exhibition, which celebrated
the centennial of the French Republic and the nineteenth-century progress
that eased the old man’s journey. Honored, eminent, and proud, Col-
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