by Jill Jonnes
While Lowrey was rounding up capital for Edison’s light, the Wizard of Menlo Park was busily hosting reporters, and by mid-October he was actually demonstrating his much bruited new light bulb. The New York Sun reporter who returned again to Menlo Park to bear witness wrote reverently, “There was the light, clear, cold, and beautiful. The intense brightness was gone. There was nothing irritating to the eye. The mechanism was so simple and perfect that it explained itself. The strip of platinum that acted as burner did not burn. It was incandescent. It threw off a light pure and white. It was set in a gallows-like frame, but it glowed with the phosphorescent effulgence of the star Altaire…. It seemed perfect.”12 Edison could be equally rhapsodic about his aborning incandescent light bulb: “There will be neither blaze nor flame, no singeing or flickering; it will be whiter and steadier than any known lamp. It will give no obnoxious fumes nor smoke, will prove one of the healthiest lights possible, and will not blacken ceilings or furniture.” Of course, what Edison didn’t mention about his wondrous new light was that it lasted only an hour or two. It was still far from commercially viable.
In an age of great formality, when gentlemen wore fine Prince Albert suits, a proper stiff collar and cravat, and a shiny silk top hat when venturing forth in public, Edison preferred to play the unschooled hick at Menlo Park, affecting rumpled blue flannel workman’s suits, silk neckerchiefs, a simple cloth skullcap, and solid boots. In truth, Edison was a voracious and penetrating reader, hungry for knowledge and possessing an amazing memory. His early deafness only made him more likely to lose himself in a book. At age twenty-one, while still working as a telegrapher for Western Union in Boston, Edison had avidly consumed all three volumes of British scientist Michael Faraday’s Experimental Researches in Electricity and Magnetism. Faraday became an immediate hero, a poor London boy who rose to the top ranks of science on his brains and hard work. To Edison, Faraday had been living proof that the secrets of nature could be revealed through determined experiment and astute observation.
That November, Edison immersed himself in journals and books about the gas lighting industry, knowing that he had to understand what kind of system he would be challenging. Since the 1840s, the quarter of Americans who lived in reasonably big towns and cities had had access to gas lighting. The great majority of the nation, however, still lived out on farms and in villages and used cheap tallow candles, whale oil, or kerosene for light. Only in bigger cities was it economical for gas made from coal to be piped along under the streets, where it lit up street lamps, and from the street into stores, theaters, factories, and homes, traveling just as water did, through special pipes. Meters recorded usage. Of course, each gaslight had to be individually lighted and snuffed out and its glass globe cleaned. Each gas flame flickered and gave off, as it burned, small quantities of ammonia and sulfur, as well as carbon dioxide and water. Over time, these fumes visibly blackened not just the encasing glass globe, but a room’s interior decor. Crowded, closed rooms lit by gas could quickly become deficient in oxygen and make people feel ill. Electricity had none of these drawbacks.
Beloved as Edison was by an awed and respectful public, his cocky ways and phenomenal early success had deeply irked his many scientific and inventing rivals, especially the gentlemen of academia. As the press breathlessly parroted Edison’s overblown light bulb claims, the scientists responded with disdainful disbelief. In Britain, Professor Silvanus Thompson scoffed in a public lecture, “We have heard a great deal of late of Mr. Edison’s discovery of a means of indefinitely dividing the light. I cannot tell you what his method may be, but this I can tell you, that any system depending on incandescence will fail.” Another prominent English electrician, John T. Sprague, declared, “Neither Mr. Edison nor anyone else can override the well-known laws of Nature, and when he is made to say that the same wire which brings you light will also bring you power and heat, there is no difficulty in seeing that more is promised than can possibly be performed. The talk about cooking food by heat derived from electricity is absurd.”13 They were joined by their countryman and fellow electrical scientist William Preece, who jeered that “a subdivision of the electric light is an absolute ignis fatuus.” The Latin phrase meant literally “foolish fire,” but it was an even worse insult because it referred to almost imaginary swamp gases.14 But such was Edison’s worldwide reputation that gas stocks in the United States and En-gland plunged in value. British Parliament tried to reassure investors by appointing a committee to review Edison’s claims. The conclusion: Edison’s wild dreams might be “good enough for our transatlantic friends” but were “unworthy of the attention of practical or scientific men.”15
Meanwhile, back at Menlo Park, where only the regular passing of Pennsylvania Railroad trains disturbed the bucolic tranquillity, Edison was settling into what he now appreciated was a far more difficult task than he had imagined. Swept up in his Promethean dream, Edison worked feverishly amid the batteries and bottles, seeking the ideal, long-burning filament, the properly shaped glass, the perfect atmosphere within that glass. Because he was inventing not just a light bulb, but a whole electrical power network to run those light bulbs, he was already thinking about the problem in terms of what made economic sense. Very early on, Edison had realized that—contrary to common electrical wisdom—he should be seeking to create incandescence with a very high-resistance material. Those inventors who had walked the light bulb path previously had all veered toward the path of low-resistance materials. But, always conscious of ultimate network costs, Edison concluded that the only way to diminish the horrific cost of copper wire for transmission was to run very low currents through thin copper wires. According to Ohm’s law, first formulated by a German physicist in 1827 and as yet little understood or honored, the magnitude of the electrical current flowing in a conductor (amperes) was equal to the electromotive force (this being the pressure or volts) divided by the resistance to the current, the resistance being measured as ohms. So Edison calculated that if he was going to run a low current (of 1 or 2 amps) through his thin copper wires to save money, he would have to develop a high-resistance light bulb (200 ohms) operating at a relatively low voltage (110 volts). When he had demonstrated his breakthrough bulb in mid-October to the journalists, it featured a thin incandescent spiral of platinum inside an orange-size glass globe atop a thin neck. And, indeed, it gave a quite satisfactory light—but only for an hour or so.
The truth was, Edison was having trouble finding a reliable high-resistance filament. He was getting disenchanted with platinum, which took high heat well but was fragile and simply did not burn for all that long. So he plugged away, looking for something better. But just as he had made the important realization that high resistance was key, so too had he discovered that the greater the vacuum inside the light bulb, the longer and better the filament burned. Therefore much time and energy were applied to developing better vacuum pumps. By February of 1879, Edison was almost completely preoccupied with finding the perfect high-resistance material and the ideal vacuum. Originally, he assumed he would use William Wallace’s direct current generator to light up his lamps. But just as he had concluded that in order to slash copper costs he would need low currents pulsating invisibly over his wires and a high-resistance filament, now he realized he must have more powerful generators to supply the necessary horsepower for the many thousands of light bulbs he envisioned radiating their cool, quiet glow in Manhattan’s gloomy offices and brownstones. In his usual methodical way, Edison had ordered the five best existing dynamos and begun making improvements, homing in on how the armatures were wound and then the size and shape of the all-important magnets.
Grosvenor P. Lowrey, meanwhile, had been importuning Edison to let him escort his increasingly restive Wall Street investors out to Menlo Park to see firsthand his wonderful progress. After all, Edison felt free to brag to journalists that he was making this or that marvelous breakthrough. They also knew he had already spent prodigious sums—of their money. In January, Ediso
n had written a friend, “The fund I have here is very rapidly exhausted as it is very expensive experimenting. I bought last week $3,000 worth of copper rods alone, and it will require $18,000 worth of copper to light the whole of Menlo park 1⁄2 mile radius.” At the same time, rumors were circulating that Edison was hopelessly bogged down. So, on the raw, chill evening of Monday, March 26, Edison played host to the money men. Lowrey and the financiers trooped off the train and up to a trim new brick building. There Edison met them in the warmth of the elegant office and welcomed them into the upstairs library, all furnished—at Lowrey’s insistence—in the finest cherrywood furniture. Wall Street millionaires and other important visitors required more than a shack.
Edison spoke for half an hour or so about progress on various fronts: a better filament—platinum plus iridium, tighter vacuum, improved DC dynamo. Then he led the way through the blustery raw evening to the nearby laboratory. It was a moonless night, very dark out, ideal for Edison to display his platinum bulbs in the pitch-black lab. The New York Herald reporter described twelve incandescent bulbs in the large machine shop doing the work of eighteen gas burners: “The light given was clear, white and steady, pleasant to the eye.”16 So the money men saw that Edison was making progress, and the journalist from the Herald duly reported, “All were much pleased with the result.” Yet the hard truth was that even the improved platinum light bulb—despite Edison’s assertions to reporters that it was ready for the world—was nowhere close to fully functional. Nor had Edison yet improved any of the DC dynamos enough to show one off as his own. While this show was calculated to convince the naysayers that Edison was on the verge of building his central generating station in downtown Manhattan and lighting up New York with electricity, he had a great deal more work to do.
By late April of 1879, the Menlo Park gang had all reason for genuine cheer, for they had at last devised a superior dynamo whose appearance earned the affectionate nickname the “long-legged Mary-Ann.” Edison’s machine had a pair of three-foot-tall iron poles (hence, the legs). What was really new was placing “the dynamo’s armature between the poles of a powerful, oversized magnet … a concentrated source of Faraday’s lines of magnetic force.”17 Edison’s generator was far superior to existing electrical generators, more efficient, and capable of lighting many light bulbs. He did this by “making the internal resistance much smaller than the external load, rather than having equal internal and external resistance,” as was the norm.18 But what light bulb? For all of Edison’s advances in understanding resistance and vacuum, practical success on the filament remained maddeningly elusive. All through the spring and summer, the Menlo Park gang laboriously tinkered in fits and starts with endless variations of the platinum-filament bulb. In August, the young German immigrant glassblower Ludwig Boehm joined the crew, installing his bellows and glassblowing table in a corner. A dandyish lad, he wore pince-nez and was quick to remind others that he had studied with the great German master Heinrich Geissler. At a time when the Menlo gang was starting to feel the wearying effects of months of frustration, Boehm’s lively zither playing provided a pleasant diversion on warm evenings.
As October rolled around and the air grew brisk and the large ash tree outside the laboratory shed its leaves, Edison and Charles Batchelor began experimenting with baked carbon filaments, the first ones being made from kerosene lampblack that was rolled into reed-thin strips, carefully coiled, and then gently carbonized in a furnace. During the testing of these lamps, Batchelor was always assisted by young Francis Jehl, who was in charge of making sure the batteries were fresh and full of power. Jehl also had the slow and tedious ten-hour task of evacuating (with the unwieldy vacuum pump) as much air as possible from each new carbon-filament bulb tested. Then, on October 22, Batchelor wrote in the extremely detailed Menlo Park lab notebooks, “We made some very interesting experiments on straight carbons made from cotton thread.”19 A plain cotton thread had been baked in the special carbonizing oven, installed gingerly in the filament holders, and fitted into one of Boehm’s handblown pear-shaped bulbs; then the bottom was closed and the air in the bulb was slowly, slowly pumped out by Jehl. When attached to the batteries and turned on, this lamp showed resistance above 100 ohms. Moreover, these thread-filament bulbs burned for two and three hours, a signal improvement over platinum. Batchelor pressed on, systematically testing eleven other fiber variations—“thread rubbed with tarred lampblack,” “soft paper,” “fine thread plaited together 6 strands,” “cotton soaked in tar (boiling) & put on.”
At 1:30 in the morning, Batchelor and Jehl, watched by Edison, began on the ninth fiber, a plain carbonized cotton-thread filament (in a horseshoe shape) set up in a vacuum glass bulb. They attached the batteries, and the bulb’s soft incandescent glow lit up the dark laboratory, the bottles lining the shelves reflecting its gleam. As had many another experimental model, the bulb glowed bright. But this time, the lamp still shone hour after hour through that night. The morning came and went, and still the cotton-thread filament radiated its incandescent light. Lunchtime passed and the carbonized cotton fiber still glowed. At 4:00 P.M. the glass bulb cracked and the light went out. Fourteen and a half hours! Francis Upton, of the soulful dark eyes and graduate degrees, the one Edison man trained in math and physics, now began evaluating the electrical properties—the improved filament and superior vacuum—of this most promising experimental lamp. On November 4, Edison applied for the light bulb patent that would catapult him to even greater fame—the carbonized cotton-thread horseshoe-shaped filament burning inside a pear-shaped bulb largely voided of air.
Edison now settled in with his unlit cigar and his verdigris microscope, systematically examining hundreds of other prospective filament fibers. Those whose structure looked promising he passed over to the genial Charles Batchelor, whose great patience and wonderful dexterity helped the Edison lab work methodically through Chinese and Italian raw silk, horsehair, teak, spruce, boxwood, cork, celluloid, parchment, and New Zealand flax, to name but a few. But most memorable and most amusing were the hairs harvested for possible filaments from the “luxurious beards” of Swiss machinist John Kruesi and a Scotsman from Michigan. Recalls Jehl, “Bets were placed with much gusto by the supporters of the two men, and many arguments held over the rival merits of their beards.”20 Kruesi’s carbonized beard hair filament flamed out first, making him the loser of the fiber “derby,” a loss followed by much good-natured grumbling about unfair discrepancies in currents. Ultimately, carbonized cardboard emerged that fall as the best of the possible filaments—even better than the carbonized cotton—and production was begun.
The whole atmosphere at Menlo Park quickened during November and early December of 1879, for their official public display was to be New Year’s Eve. They had their light bulb. They had their generator, the “long-legged Mary-Ann.” Now they ordered steam engines to power them. While these were the major components of the system, Edison also had had to invent and manufacture dozens of other parts, including switches, fuses, distribution lines, regulators, and fixtures. Western Union agreed to send out men to help with the electrical wiring. The ever faithful Lowrey was kept informed. (Edison, former ace telegrapher, himself often personally tap-tap-tapped his telegraphic communications to Lowrey’s Manhattan office.) Flush with success, Edison was gearing up for the all-important public lighting display, the radiant refutation of all his academic naysayers. More important, he knew he needed to woo back his surly Wall Street investors so they would reopen their wallets for the next phase, creation of a prototype of the New York electrical network. Rumors in the New York press were rampant, for after all, travelers in the Pennsylvania Railroad trains passing at night began to report brilliant lights gleaming through the windows of Menlo Park edifices. Edison’s colleague Francis Upton wrote jubilantly to his father that December of 1879, “The light is still prosperous; I have had six burners in my [Menlo Park] house during the past week and illuminated my parlor for the benefit of a party of visitors
from New York. The exhibition was a success. Mr. Edison’s and my house were the only ones illuminated. There will be a great sensation when the light is made known to the world for it does so much more than anyone expects can be done.”21
Edison, who had always been easily available to any reporter looking for a story, now put off all requests. He allowed access only to his favorite, Marshall Fox of the important and influential New York Herald, a Republican daily preeminent in foreign news, expensive to purchase at three cents, and consequently read only by the best people. But the condition was that Fox publish the article, which Upton would help edit, only when Edison gave the go-ahead. Yet in true journalistic fashion, Fox broke the story as soon as possible. Thus, on Sunday, December 21, 1879, readers of the Herald opened their papers to find a full-page story headlined EDISON’S LIGHT—THE GREAT INVENTOR’S TRIUMPH IN ELECTRIC ILLUMINATION—A SCRAP OF PAPER—IT MAKES A LIGHT, WITHOUT GAS OR FLAME, CHEAPER THAN OIL—SUCCESS IN A COTTON THREAD. “Edison’s electric light,” wrote Fox, “incredible as it may appear, is produced from a tiny strip of paper that a breath would blow away. Through this little strip of paper is passed an electric current, and the result is a bright, beautiful light, like the mellow sunset of an Italian autumn…. And this light, the inventor claims, can be produced cheaper than that from the cheapest oil.”