City of Light: The Story of Fiber Optics

32 CITY OF LIGHT
made: ‘‘All that I remember is that it scratched, and I couldn’t sit down for
fear of breaking the glass threads.’’ 15
The real role of the glass dresses, neckties, and other fabrics was to publicize
new glass technology. Nineteenth-century industry had made glass a
better and cheaper product, commonplace from windows to whiskey bottles.
Glass fabrics promised new marvels for the twentieth century. Part of the
attraction was the way light glittered from the glass, but the very idea of
flexible glass threads was itself a wonder.
Industry saw a host of uses for glass fibers besides clothing. Glass fibers
could withstand corrosive chemicals, so chemists and druggists used them to
filter solid particles out of liquids. Woven glass fibers were used as bandages.
Industry realized that tangled glass fibers, called glass wool, made a good
insulator, and packed them around steam pipes. Industry would pay more
per square inch for glass fabric than people would pay for clothing—and
didn’t worry if it was scratchy.
As interest grew in glass fibers, engineers and scientists devised new ways
to make them. One was to suspend a glass rod vertically, heat the lower end
in a furnace, and draw a fine filament downward from the molten zone. In
one early scheme, the experimenters hung a weight from the bottom of the
rod, which dangled below the hot zone of a cylindrical furnace. Rapid heating
softened the glass quickly, and the weight stretched it into a thin fiber. The
scheme also stretched glass tubes into fine capillaries, allowing British scientists
to make 0.001 millimeter tubes with walls thinner than 0.0001 mm. 16
Boys’s instruments interested other experimenters in quartz fibers. A few
companies started manufacturing them, but they were expensive, so Scientific
American published a do-it-yourself recipe. Readers wanting long, fine fibers
were told how to make their own miniature catapults—a design that owed
much to Boys’s crossbow. 17
Nonetheless, glass fibers remained a specialty item for the first three decades
of the twentieth century. Only in Germany did an industry develop,
and that only because Allied embargoes cut the country’s supply of asbestos
during World War I. Natural fibers were better—and cheaper—for insulation
and filtering, and in that innocent age the health hazards of asbestos were
unknown.
In December 1931 engineers at the Owens-Illinois Glass Company in Newark,
Ohio, demonstrated the first commercially viable technique for massproducing
inexpensive glass fibers. They abandoned the idea of drawing one
fiber at a time. Instead, they blew hot air into molten glass, splattering short,
coarse threads of liquid into the air, where they quickly solidified. The process
yielded a soft, fleecy mass of flexible fibers—glass wool, the fiberglass used in
modern insulation.
The Corning Glass Works was also working on glass fibers, and the two
companies formed a joint venture, the Owens-Corning Fiberglas Corporation.
18 By 1935, they were producing fibers so strong, fine, and flexible that
they could be woven into cloth, which could be bent and folded without