City of Light: The Story of Fiber Optics

FIBERS OF GLASS 31
Armed with a high-temperature oxy-hydrogen flame, Boys tried a variety
of minerals that resembled glass in some ways. Some, like sapphire and ruby,
did not stretch into fibers. Yet others did work. The best of these was natural
quartz, crystals of almost pure silica. Much thicker than molten glass, molten
quartz dragged heavily on the miniature arrows, so they usually fell far short
of their target. It took many tries before Boys could stretch quartz into fibers,
but success proved exciting. Some fibers were ‘‘so fine that I believe them to
be beyond the power of any possible microscope,’’ he told the Physical Society
in London on March 26, 1887. 13
The best of his threads were as strong as steel wires the same size, a marvel
for a material always considered fragile. Their thinness and strength made
the quartz fibers ideal for suspending objects on torsion balances to measure
delicate forces. Boys used them in an instrument he called a ‘‘radiomicrometer,’’
with which he could detect the heat from a candle nearly two
miles (three kilometers) away. He was utterly delighted with the fibers and
with the measurements they let him perform.
Boys stretched quartz fibers in front of him and found that in the right
light they glittered with colors. He stretched many fibers parallel to each other
and they acted like a diffraction grating, an array of parallel lines that spreads
out a spectrum like a prism. He must have seen Sir Francis Bolton’s illuminated
fountains; the exhibit grounds were close to his college. Yet Boys did
not record for posterity any experiments with light guiding, even the results
of pointing one end of a fiber at a lamp and looking into the other end.
Perhaps he tried and saw nothing, because his fibers were not clear enough.
Perhaps it was impractical with the fine fibers that fascinated him the most.
Or perhaps he thought the idea too trivial to mention at a time when anyone
could marvel at illuminated fountains displaying the same principle far more
spectacularly.
Glass Fabrics
A German immigrant named Herman Hammesfahr patented glass fibers in
America, but it took him years to interest others in his vision of glass fabric.
He succeeded when the Libbey Glass Company wanted something spectacular
to show at the 1892 World’s Fair in Chicago. At first, two young women
wove glass fibers into fabric for lamp shades. Then the fabric caught the eye
of actress Georgia Cayven, who wanted a dress made of it. Hammesfahr succeeded
by combining satin thread with the glass fibers. Libbey showed the
dress at the fair, where it caught the eyes of many fairgoers, including Princess
Eulalie of Spain, who paid $30,000 for a copy. 14
Glass fabrics glittered brightly at the turn of the century, but they were
hardly practical. Many years later, Hammesfahr’s granddaughter recalled
modeling at the 1904 World’s Fair in St. Louis a glass dress her mother had