Brilliant (12 page)

One of the first experimenters in Leiden found that the jar contained enough power to make his whole body quiver. "I advise you never to try [it] yourself," he wrote to a colleague, "nor would I, who have experienced it and survived by the Grace of God, do it again for all the kingdom of France." But many others across Europe and in America did try it in the succeeding decades. Men administered shocks to small animals and birds, to themselves and their wives; they suffered nosebleeds and fevers, convulsions and weakness. Still they experimented. Abbé Jean-Antoine Nollet, at the court of Louis XV at Versailles, in an effort to see how far a shock could travel, sent a charge through 180 soldiers who'd joined hands. He was satisfied to see that they all jumped in unison, and then he tried the experiment on 750 Carthusian monks, who, holding wires between them, formed a line 5,400 feet long. As the abbé sent the current through, they, too, all jumped at the same moment.

Experimenters made bells ring, set rum on fire, and sent sparks shooting around gilded picture frames. They generated "electric kisses" by suspending a young woman in the same way Gray had suspended his "dangling boy." They then invited men from the audience to kiss her on the cheek, and sometimes the charge was significant enough to crack teeth. Still, electricity remained "a vast country, of which we know only some bordering provinces," and its experimenters were thought to be dabbling in a toy science, for no one had yet found a practical application for its power.

Benjamin Franklin, one of the eighteenth century's most tireless "electricians"—a phrase he coined and by which electrical experimenters were then known—was "chagrined a little that we have been hitherto able to produce nothing in this way of use to mankind." He knew electricity's true power only too well, having received at least one considerable jolt. "I have lately made an experiment in electricity that I desire never to repeat," he explained in a letter to a friend in Boston.

Two nights ago, being about to kill a turkey by the shock from two large glass jars, containing as much electrical fire as forty common phials, I inadvertently took the whole through my own arms and body.... The company present ... say that the flash was very great, and the crack as loud as a pistol; yet, my senses being instantly gone, I neither saw the one nor heard the other; nor did I feel the stroke on my hand, though afterwards found it raised a round swelling where the fire entered, as big as half a pistol-bullet, by which you may judge the quickness of the electrical fire, which by the instance seems to be greater than that of sound, light, or animal sensation.

Franklin advanced the understanding of electricity with countless experiments and considerable writings on the subject, and he clarified some of its mystery. Philip Dray notes that Franklin "was the first to discover that the [Leyden] jar's stored charge was not in the water, as others had believed, but in the glass. The glass was a dielectric, meaning it stored and allowed the passage of electricity but did not conduct it." Perhaps most significantly, Franklin—like Stephen Gray and Abbé Nollet—suspected that lightning and the electrical charges they'd created in their experiments were one and the same substance. The common belief at the time, however, held that lightning—heavenly fire—was its own distinct phenomenon and a manifestation of the will of God, a belief that may have been reinforced by the fact that churches and monasteries, with their high steeples and bell towers, were often struck during storms. "There was scarce a great abbey in England which was not burnt down with lightning from heaven," notes a church history of Britain. Many thought such destruction could be warded off by the sounding of church bells during electrical storms, though the practice only served to hasten the deaths of countless bell ringers.

Franklin suggested a new way to ward off such destruction. "There is something ... in the experiments of points, sending off or drawing on the electrical fire," he wrote. "For the doctrine of points is very curious, and the effects of them truly wonderful.... I am of the opinion that houses, ships, and even towers and churches may be effectually secured from the strokes of lightning by their means." When he began to promote the use of lightning rods on buildings, he encountered considerable resistance from church leaders, who claimed the rods were blasphemous and warned that drawing lightning from the sky would cause earthquakes. He was undeterred, however, and his observations of the workings of lightning rods led to his most renowned experiment, which proved that the charges in the heavens and those in Leyden jars were one and the same.

In July 1750, Franklin proposed that a sentry box, large enough to house a man and with a pointed rod rising from it, be built. It would contain an electrical stand which, if it

be kept clean and dry, a man standing on it when such clouds are passing low might be electrified and afford sparks, the rod drawing fire to him from a cloud. If any danger to the man should be apprehended (though I think there would be none), let him stand on the floor of his box, and now and then bring near to the rod the loop of a wire that has one end fastened to the leads, he holding it by a wax handle; so the sparks, if the rod is electrified, will strike from the rod to the wire and not affect him.

In May 1752, before he could conduct his experiment, a French physicist successfully followed his suggestion. The following month, Franklin, knowing nothing of the events in France, carried out a similar experiment with a silk kite, a hemp rope, and a key, which he later detailed:

As soon as any of the thunder-clouds come over the kite, the pointed wire will draw the electric fire from them, and the kite, with all the twine, will be electrified, and the loose filaments of the twine will stand out every way, and be attracted by an approaching finger. And when the rain has wetted the kite and twine, so that it can conduct the electric fire freely, you will find it stream out plentifully from the key on the approach of your knuckle. At this key the phial may be charged; and from electric fire thus obtained spirits may be kindled, and all the other electric experiments be performed which are usually done by the help of a rubbed glass globe or tube, and thereby the sameness of the electric matter with that of lightning completely demonstrated.

To connect heavenly forces to the "virtue" that humans had puzzled over since the first sparks were rubbed from amber elevated electricity above the realm of toy science and entertainment. As Philip Dray notes, "Franklin's conclusions demanded that electricity join gravity, light, heat, and meteorology in any account philosophers offered for the majestic workings of nature." Still, half a century after Franklin's kite experiment, at the end of the eighteenth century, in a world illuminated at best by the Argand lamp, the understanding of electricity had hardly advanced any further, hampered in part by the limits of the Leyden jar, which could only bring experimenters so far, since it stored limited energy.

In the late eighteenth century, in Italy, Alessandro Volta challenged Luigi Galvani's conclusion that convulsions in frogs, which Galvani had hung from brass hooks upon an iron trellis, were caused by innate electricity within the animals themselves. Volta argued that the convulsions were caused simply by the contact between the brass and the iron, and he proved his theory by creating the first modern battery, which he described in a letter to the Royal Society in London in 1800:

I obtain several dozen small round plates or disks of copper, brass, or better of silver, an inch in diameter, more or less; for example coins, and an equal number of plates of tin, or, what is still better, of zinc, of the same shape and size approximately.... I prepare besides a sufficiently great number of disks of cardboard, or cloth ... capable of imbibing and retaining considerable water.... I place, generally horizontally, on a table or other base, one of the metallic plates, for example, one of silver; on this first, I then place a second of zinc; on this second, I place a moistened disk; then another plate of silver, followed immediately by another of zinc, to which I can make succeed a moistened disk. I then continue ... always in the same direction.... I continue, I say, to form by many of these sets a column sufficiently high that it may be able to stand upright.

The charge would last for as long as the electrochemical interactions between the liquids and various metals lasted. Volta had created a sustained, continuous flow of electricity. As Park Benjamin, writing in the nineteenth century, noted, Volta's invention "made electricity manageable. He reduced the infinite rapidity of the lightning stroke to the comparatively slow but enormously powerful current, which in the future was destined to carry men's words from one end of the world to the other, and to produce the dazzling light inferior only to the solar ray."

Volta's "pile" immediately intrigued scientists across Europe and America, none more so than Sir Humphry Davy—creator of one of the first miners' safety lamps—who, at the beginning of the nineteenth century, held a post as chemist at the Royal Institution in London. Davy worked at refining Volta's pile and eventually had large batteries built in the basement of the institution's laboratory. He carried out a series of experiments with them, including demonstrations of the first electric lights. In 1802 he succeeded in making a platinum filament glow, if only momentarily, by infusing it with electric current. Then in 1809, with the aid of the largest battery yet—consisting of two thousand pairs of plates—he demonstrated the first lasting electric light, the voltaic arc. He passed a current through a charcoal stick, which served as a conductor of electricity; then he touched another charcoal stick to the first, and a spark jumped from the first to the second. As he pulled them apart, an arc of brilliant blue-white light leapt across the heated air between them. But light wasn't created by the arc alone; the carbons glowed incandescently.

Davy never took the voltaic arc beyond the demonstration stage—an enduring, practical electric light was still many decades away, for considerable problems had to be overcome. Not only did Davy's charcoal electrodes burn quickly and unevenly, but as the carbons burned down and the gap between them widened, the light sputtered, then failed. Scientists had to develop electrodes that would burn slowly and steadily, at a constant distance from each other. The greater challenge, however, lay in producing a more enduring power system than the batteries of the day, and widespread arc lighting would depend on a reliable electric generator, or dynamo, as it was commonly called. That would not arrive until well after 1831, the year Michael Faraday established the principle of electromagnetic induction.

Early arc lights ran on batteries and on small steam-driven generators, but this, as Wolfgang Schivelbush notes, was a step back from gaslight, because there was no possibility of widespread interconnected lighting. Their use was limited to outdoor work yards and lighthouse towers, or for special display and spectacle, as at the coronation of Tsar Alexander II in 1856, when "the city of Moscow was lighted by numbers of electric lamps suspended in the old bell-tower of the Kremlin, a thousand gilded domes glittering in the unearthly radiance, in happy contrast with the quaint arches of the old cathedral close at hand, while the river Moskva was transmuted into a stream of liquid silver."

By the late 1870s, Russian inventor Paul Jablochkoff had made major improvements to the arc lamp. In his design, the carbons, separated by gypsum insulation, stood upright and were set side by side; his "candles" were lit at the top and burned down. Jablochkoff bundled four of them under a glass globe—much more efficient than burning in open air—and devised a regulator so that as one extinguished itself (it could last for about two hours), the next automatically began to burn. The lights ran on the improved generators of the time—by then, Belgian Zénobe Gramme had built a steam-driven dynamo powerful enough to drive a series of streetlights. Jablochkoff's "candles" first lit public halls and department stores, then in 1878 the first arc streetlamps appeared in London and along the Avenue de l'Opéra in Paris, where, being considerably brighter than the traditional gas lamps—perhaps 800 candlepower apiece—they were set about 150 feet apart. Each one replaced up to six gas fixtures.

Until the advent of arcs, street lighting had inched forward, the greasy candles in windows giving way to lanterns, then gaslight, and with each modest improvement—deemed remarkable—life filled up the new space given it in the night. Old light retreated into the far streets and the lesser-known neighborhoods, disregarded and disparaged in relation to the new. But always streetlamps had been light vessels, following the pattern of the streets, and each post cast its own halo that gradually diminished into shadow. People moved in and out of illumination, and streetlamps were an integral part of the streetscape: lamps on the street were in conversation with lamps in homes, cafés, and restaurants; in conversation with the dusk, then the night.

Arc lights fundamentally changed all that. They were exponentially brighter than any previous light—ranging from 500 to 3,000 candlepower. But also the very quality of the light was different. Even under the most efficient oil and gas lamps, as is usual in the dark, the eye saw with its retinal rods. Yet arc lights were so similar to daylight that the human eye worked as it did during the day, using its retinal cones. These lights were so intense that they had to be hung considerably higher than the existing gas and oil streetlamps, above the direct line of human vision, and the light poured down over large areas. The streets no longer appeared as avenues lined with distinct lamps, with "spark lining up with spark." Rather, the light hit off walls and entered houses and was so bright it was claimed that one could see the flies on the walls and read a newspaper streets away from the source. Men and women "suddenly found themselves bathed in a flood of light that was as bright as the sun. One could in fact have believed that the sun had risen. This illusion was so strong that birds, woken out of their sleep began singing.... Ladies opened up their umbrellas ... in order to protect themselves from the rays of this mysterious new sun."