by James Tobin
Like Langley, he was well aware that such experiments would expose him to ridicule. But he would not stay silent. The power of his obsession was evident in an exchange with an eminent friend, the great English physicist Lord Kelvin. In a crowded social gathering in Halifax, Nova Scotia, Kelvin—whom Mabel thought a “kindly, loveable, simple man”—remarked to Bell that he regretted the American’s foray into aeronautics. When Bell objected, the two “plunged right into scientific talk right there in the midst of the crowd.” Afterward, Mabel wrote to Kelvin, insisting her husband’s work was not a lark but a serious scientific endeavor. The Englishman replied that he never doubted Bell would proceed “by careful and trustworthy experiment. Even if the result is to demonstrate to himself that a practical useful solution of the problem is not to be found, I am sure what he finds by his observations and measurements will be very interesting.” His intent, Kelvin said, had been only “to dissuade [Bell] from giving his valuable time and resources to attempts which I believe, and still believe, could only lead to disappointment, if carried on with any expectation of leading to a useful flying machine.” Yet the warning of this man, far more learned in basic science than himself, failed to deter Bell. Two years earlier he had taken his photographs of Langley’s models wheeling overhead, and they spoke more loudly than Kelvin’s objections.
Bell tested many forms of apparatus related to flight—whirling horizontal rotors; hand-held aeroplanes modeled after Pénaud’s toys; gunpowder rockets; propellers. None led to notable success. Shortly after the death of Otto Lilienthal in 1896, he wrote: “I am finding out in the laboratory that a great deal has yet to be learned concerning the best way to combine aeroplanes or aerocurves—so as to gain the full benefit of the surfaces.”
ON A VACATION in the mid-eighties, the Bells had fallen in love with the remote village of Baddeck, Nova Scotia, a cool, unspoiled place of long vistas and transplanted Scots who reminded Bell of his homeland. So did the twisting, hundred-mile reach of ocean water the locals called Bras d’Or—“arm of gold.” On a peninsular headland across the water from Baddeck, the Bells built a massive, turreted house they named Beinn Bhreagh (ben VREE-ah), Gaelic for “Mountain Beautiful.” The house could sleep twenty-six, not counting servants, with eleven fireplaces, and in the high months of summer it was filled with relatives and friends. These groups often included Samuel Langley (whom Bell’s daughters called “grandfather”), and Simon Newcomb (who once debated Langley for hours on the Bells’ great veranda on the question of how a cat, dropped upside down, could land on its feet). Over the years, the Bells built stables, gardens, wharves, guest cottages, a laboratory, and twelve miles of roads. By 1900 the big house was the center of a private little kingdom. For his own castle keep, Bell used a beached houseboat. He would sit there all alone, sometimes for an entire weekend, sketching designs and capturing “fugitive thoughts,” unable to set his obsessions aside and rest.
With its long slopes to the water and stiff breezes nearly every day, Beinn Bhreagh was a perfect setting for flying kites, which Bell began to do in 1898. It was a relaxing pastime only at first—and even then, Bell made notes. He had learned in the telephone patent wars never to leave any scientific observation, however casual, unrecorded. When sharp breezes blew off the Bras d’Or, he would spend the entire afternoon on a long meadow that soon became known on the estate as the “Kite Field.” Like any heedless hobbyist, he put friends and family to sleep with talk of this new passion. “I suppose Mr. Bell has nothing but kites and flying-machines on his tongue’s end,” Helen Keller remarked in 1901. “Poor dear man how I wish he would stop wearing himself out in this unprofitable way.” The people of Baddeck were baffled. A boatman told a visitor: “He goes up there on the side of the hill on sunny afternoons and with a lot of thing-ma-jigs fools away the whole blessed day, flying kites, mind you. He sets up a blackboard and puts down figures about these kites and queer machines he keeps bobbing around in the sky. Dozens of them he has, all kinds of queer shapes, and the kites are but poor things, God knows. I could make better myself. . . . It’s the greatest foolishness I ever did see.”
For Bell, the appeal of a kite, especially a big one, lay in its marvelous violation of the law of gravity. “There is a great fascination in watching large structures floating in the air; structures of great weight as well as great size,” he said. And once he had made a significant weight float overhead, and remain in his control, the next speculative leap became irresistible. “One cannot help dreaming a little concerning the possibility of a man being carried up in one of these structures, of an engine and propeller being installed, and then cutting loose from the anchor mooring that constitutes the machine as a kite and flying off under its own propulsive force.
“In a large kite I see a flying machine at anchor.”
FROM THE LIBRARIES OF WASHINGTON, Bell gathered all the writings he could find, hundreds in all, on the subject of aerial navigation. He told Langley he was “surprised, indeed overwhelmed by the extent of the literature. . . . An enormous mass of material exists, which it seems to me, from the little study I have given it, to be in an utterly chaotic condition.” He set out to make an exhaustive bibliography of titles and references, convert the list to index cards, sort it from earliest to latest, “and then study the matter historically.”
In these records of tiny progress and much failure, he saw an obvious problem that other enthusiasts and experimenters seemed to ignore: Those who actually attempted to fly tended to die shortly thereafter. In Bell’s eyes, the deaths of Otto Lilienthal and Percy Pilcher proved that the aeroplane design, in particular, was simply too dangerous to provide the ultimate answer to the problem. Even Langley’s aerodrome looked too risky to Bell. “The great difficulty in developing an art of aerial locomotion lies . . . in the difficulty of profiting by past experience,” he wrote. “A dead man tells no tales.”
So, with safety foremost in his mind, he sketched designs for a radically different sort of flying machine. First, it must be inherently stable. That is, if wind gusts or an operator’s error knocked the machine off kilter, its shape would naturally bring it back into balance. He insisted on this. Second, the machine must be light. The heavier it was, the faster it must go to attain lift, and speed was a killer. Since launches and landings were the points of greatest peril, the craft should be flown over water, a more forgiving medium than the hard ground. The ideal flying machine would rise straight up, and it would be capable of hovering like a kite (but without a line), allowing the operator to drop a rope ladder and step safely down to terra firma. It was an extraordinary image—a man-carrying device floating in one spot overhead, oblivious both to gravity and to the wind.
To gain this end, a kite was the ideal experimental device. The crazy “thing-ma-jigs” glimpsed by the Baddeck boatman actually represented stages in the evolution of Bell’s thinking. There were circular shapes and paddle-wheel shapes. Others were stars. One was shaped like an H. Some looked like giant spools of thread. Often Bell imitated the simpler designs of the Australian engineer Lawrence Hargrave, inventor of the box kite. Hargrave was another fervent believer in the cause—“I know that success is dead sure to come,” he told Chanute. His box kite was a rectangular compartment, or cell. It was really a twin of the biplane—two plane surfaces connected at their ends and capable of lift when they encountered the wind. In 1894 Hargrave rose to a height of sixteen feet on the strength of four interconnected box kites. He never did better, but his basic design spread through Europe and North America.
What appealed to Bell about the box kite was its stability. If a small box kite flew stably, why not a big one? But here he collided with the rule that Simon Newcomb had cited time and again—any device twice as big as another of the same shape will be not twice as heavy but eight times as heavy. With hopes of lifting the weight of a man, Bell built box kites with rectangular cells as big as rooms. But the bigger the kite, the poorer it flew.
Bell drove in upon Newcomb’s problem. I
n 1901 he struck upon the idea of joining many small box kites together. “Do not increase the size of the cell, but compound small cells into a large structure,” he jotted in his lab book, “and where the two sticks come together omit one, and in this way the larger kites will have less weight relatively to their surfaces than the smaller kites, and yet be equally strong.” Next came the insight that even more weight could be saved by discarding the rectangle as the basic shape. Instead, “let everything be built up of equilateral triangles. . . . Whole thing could be built up into a solid compact form of almost any desired shape.”
In Bell’s mind, a form arose that would be wonderfully strong yet wonderfully light. Its basic unit would be a pyramidal cell—a tetrahedron. That is, in the language of the patent he took out in 1904, “The tetrahedral skeleton or frame may be composed of six bars or rods so connected at their ends as to form the outlines of four triangles.” Like a three-legged stool, this was an inherently strong and stable form.
Better yet, something mysterious and wonderful happened when one joined a second cell of exactly the same size and shape to the first. Again, the first cell required six bars. But the two cells together required not twelve bars, but only nine, since the two cells shared one of their triangular faces. The new structure was twice the size of the first, but only one-and-a-half times the weight. And this paradoxical logic applied as more cells were added. The additional weight did not keep pace with the additional size.
That was not all. The simple parts—just rods of wood or a light metal, with connectors between them—could be transported, assembled, and disassembled with ease. Bell soon realized the cells’ rigidity and strength made them highly adaptable to all sorts of building projects. In fact, the first structure he assembled with them was a giant wall on the Kite Field to shield kites from the wind while they were being assembled. He built a single-cell shed on the lawn, with one side open for viewing the kite flying.I
“LET EVERYTHING BE BUILT UP OF EQUILATERAL TRIANGLES.”
Two of Alexander Graham Bell’s smaller tetrahedral kites (top); the inventor sits in a tetrahedral chair to observe his kites aloft (bottom)
Of course Bell’s key aim was not structural but aeronautical. He saw that if he covered two triangular faces with fabric, he had a pair of dihedral wings. This was “the brick, as it were, out of which the flying house must be made.” Many such “winged tetrahedral cells” joined together would resemble a great flock of birds flying in unison. And, most important to Bell, the dihedral angles of the multiple little “wings” would guarantee extraordinary stability.
He began to speak of a new theoretical model for manned flight. Langley had chosen the eagle as his model. Bell now looked to the butterfly. A reporter put it this way: “Eagle flight is marked by its strength and speed; the butterfly hovers lightly over the earth, gently rising or alighting, unambitious, but safe. Perhaps, thinks Professor Bell, man would do better to imitate this kind of flight in the first trial of his mechanical wings. An initial velocity of sixty miles an hour cannot be acquired by the new experimenter, without danger to his life and limbs, not to mention his fragile apparatus. Is there not some way by which we may learn to fly more gently?”
A mass of tetrahedral cells did not look like a wing. But it acted rather like one. With Bell watching and assistants holding the lines, the first tetrahedral-cell kite shot skyward in 1902. It whistled as it rose to an impressive height, where it remained nearly as stable in the wind as a three-legged stool on a hardwood floor.
“In multi-cellular kites of pure tetrahedral construction we have forms that seem to possess automatic stability in the air,” Bell informed Chanute. “The steadiness of flight in a gusty wind [is] really remarkable.” His hopes became faith. “Other kites, in a gust of wind, will dance about, but my kites for some reason are perfectly stable. . . . In aerial machines what we want above all things is automatic stability, and this quality is possessed by these tetrahedral kites.”
Soon after that, a tetrahedral kite with two broad banks of cells connected to each other as tandem wings, like Langley’s aerodrome, was sailing aloft. A squall hit. The kite yanked two handlers off the ground.
Bell’s kite experiments became a cottage industry. Workers from Baddeck began to cross the bay by boat each morning—carpenters to assemble the cells from sticks of wood or aluminum and seamstresses to sew silk triangles to the frames, all by hand. In this sparsely settled back country, any paid work was welcome, and Bell was known as a kindly boss. Seamstresses competed to see who could make the most cells in a week; the winner got an extra day off. When enough cells were ready, they would be joined together, sometimes hundreds in all, to form structures of extraordinary geometry.
The kites were easy to build, so Bell tried designs of endless variety and size, hoping to hit on a great flyer through dogged trial and error. No one had ever seen their like. He chose red silk for most, so they would show up well in photographs, and the color reinforced their unearthly appearance. Long afterward, a Baddeck woman who sewed cells for a dollar a day recalled the daily scene on the Kite Hill in summer. “There were so many kites, so many that never had names. They were experiments. They were really beautiful in the clear sky . . . usually in the late afternoon when the sun was going down.
“He loved to see them fly. ‘Beautiful,’ he’d say. ‘Beautiful.’”
BY 1902 MABEL BELL found her husband “continually more wrought up over his kite experiments than I like.” Yet she knew success was the only tonic for what ailed him, and she wanted it as much as he did.
“I do so appreciate all the wonderful, unfailing, uncomplaining patience that you have shown in all your work,” Mabel told Alec at one point during the kite experiments, “and the quiet, persistent courage with which you have gone on after one failure after another. How many there have been, how often an experiment from which you hoped great things has proved contrary. How very, very few and far apart have been your successes. And yet nothing has been able to shake your faith, to stop you in your work. I think it is wonderful and I do admire and love you more as the years go on. But oh how I wish that you may have success at last.”
She was especially hopeful about Bell’s prize kite of 1903. The configuration of its massed cells reminded the Bells of a soaring hawk, so they named it Oionos, for the birds of prey the Greeks watched to foretell the future. Mabel was in Washington, where the papers were full of Langley’s great aerodrome. But her money was on Oionos. “You simply must get that machine to fly,” she wrote her husband. “I have been watching a buzzard fly and it looks just like your Oinos [sic], and it goes up and down on the wind without moving it’s [sic] wings. It’s the most graceful thing in the world and we surely, surely must be able to do it. No ugly clumsy balloon thing, but a bird. . . .
“You are working so differently from all the other men, they seem so far ahead of you and yet are they really? I think not. I can not but believe the strong compactness of your machine must win through in the end. It is built according to nature’s law. . . . I love you and believe in you and your success.”
Oionos did fly—so well, in fact, that Bell believed he soon would have another great invention to give the world.
In the fall of 1905, Bell built a man-carrying kite so large it would need a wind of near gale force to get off the ground. Such a wind arrived one day in November, but the weather was so bad that Bell’s assistants refused to come over from Baddeck. “He looked gray when he came home,” Mabel said, “wrote a short note dismissing the staff and closing the laboratory, turned his face to the wall and never spoke again that day or night.”
But he went back to work on a new man-carrier. Bell had hundreds of cells on hand in his workshops. He assembled every one of them into a structure nearly twenty feet across at its widest point, with a weight of just over sixty pounds. Bell named it the Frost King, for newlywed friends named Frost in Baddeck, though the name also matched the weather. Bell equipped the kite with a fifteen-foot rope l
adder. The ladder would hang by lines some thirty feet below the kite itself. The plan was for a lightweight man to climb on the ladder when the kite was in flight, then ride it higher into the air to prove the kite’s lifting power. The rider would not control the kite. But the sheer act of lifting a man well off the ground was a key step.
And he became “more and more desperate,” not only to bring the trial off, but to capture a photograph of the scene. Apparently Bell believed that documentation of a man-carrying tetrahedral kite would give his efforts credibility among other experimenters. Certainly he knew that a photograph in such cases was worth more than a sober report.
Every morning the family scanned the water for whitecaps, the harbinger of a good wind. One day the breeze was strong enough for the Frost King to lift a Baddeck youngster several feet off the ground. But the Bells’ photographer had chosen that day to hole up in the dark room, and no other camera was handy. On Christmas Day, a good breeze pushed the kite some nine-hundred feet in the air, but by the time it was hauled down to pick up a passenger, the wind had died. Two days later Bell induced the Oionos to turn a circle in the air like a wheeling hawk—another key step. But now chances for the season were all but gone. On December 28 the Bells were due to catch a steamer bound for St. John’s, New Brunswick, where they would board a train for Washington. The steamer was approaching Baddeck when suddenly a “fair sailing breeze” came up, though from the northwest, “the worst kite quarter.” Still, it offered one last chance.