Let there be light

Memory Lane

In the photograph that is the most widely circulated image of the Ireland-born scientist John Tyndall, the influential philosopher appears to be every bit as earnest as the remarkable career he authored. A dual thicket of whiskers cascades symmetrically down each side of his narrow face, framing it in triangle and exaggerating its length. Like most men of consequence who were photographed in the 19th century, Tyndall allows no trace of a smile to compromise the sober tone of the portrait. Yet there is the barest hint of intrigue detectable in Tyndall’s stare. The faint arching of one eyebrow betrays a certain bemusement at the moment, as if Tyndall found something curious and interesting in the work of the photographer, and could not entirely contain his fascination.

That would only be appropriate, because the son of a modest Irish landowner seemed incapable of letting the physical world go about its business without close inspection and the recording of interesting observations with a hard-scrabble devotion. At Germany’s University of Marburg in the late 1840s, Tyndall earned his doctorate degree in just two years, and a few years later earned acclaim among scientists after delivering a masterful 1853 lecture on “The Influence of Material Aggregation upon the Manifestations of Force.” He would go on, with the colleague and friend Thomas Huxley, to emerge as one of the most influential “natural philosophers” of the era, a persuasive, engaging speaker who embodied a new view of science as a centerpiece of modern understanding.

Tyndall’s interests as a scientist ranged wide. Experiments in magnetism were followed in the mid-1850s by a thoughtful examination – and controversial conclusions – about the way glaciers formed and moved. Later, his principle contributions revolved around studies of the transparency and opacity of gases for radiant heat.

But Tyndall also brought to attention a feature of light that has enormous bearing for the way millions of people now receive and interact with a range of electronic information spanning TV shows, Web pages and telephone calls.

Historians who have written about Tyndall recite an 1870 experiment in which the scientist, by now a notable expert in thermodynamics, detected an interesting pattern associated with the movement of light. It was a modest experiment. A container filled with water was outfitted with a small spout allowing the liquid to pour out in a thick stream. A second container below collected the spilled water. It was what happened in between that intrigued Tyndall. By directing a beam of sunlight at the water’s stream, Tyndall demonstrated to an audience a curious phenomenon: The light appeared to follow the path of the water, as if it had been somehow captured within the flowing arc.

Tyndall’s 1870 demonstration, notes the author and fiber optics industry historian David Goff, was the first known research into the transmitting of light along a guided path. It inspired subsequent researchers to investigate further how light might be “sent” places though various networks of pipes and pathways. Eighty years after Tyndall’s seminal experiment, in the 1950s, commercial breakthroughs erupted after researchers in the private and academic sectors devised strands of glass material that could effectively do the same thing to light that Tyndall’s two-buckets-and-a-stream medium accomplished: transmit it from here to there. The devising, later, of a two-layered glass pipe (the second layer was called cladding) solved a vexing problem related to light leaking its way out of the original fiber. And in the late 1950s, the researcher Gordon Gould and scientists at Bell Laboratories applied another key enabling element to optical fiber transmission by introducing, at one end of a glass strand, a powerful laser to shove large amounts of light down the microscopic fiber optic array.

Today an entire communications infrastructure revolves around transmitting light waves over high-capacity optical fibers, and the debate over how far fiber ought to extend into residential communications networks is the central architectural issue of the modern telecommunications industry. Verizon Inc.’s ambitious and expensive uprooting of a nearly century-old copper phone network in favor of supercharged, modern fiber optic connections is currently roiling the sector and prompting some stern soul-searching within the cable industry and elsewhere. Like so many advancements in communications technology, it is that way not because of sudden breakthroughs, but a long progression to which many innovative thinkers have contributed. That, plus a simple stream of water, and an insatiably curious Irishman who couldn’t help but notice how things seemed to behave.

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