distribution system, a lot can be accomplished. And without taking a large number of people away from the activities of your master plan.”
Alf Richards pursed his lips, dubious but thoughtful. Ruffin sensed an opportunity and pursued it.
“Just spare a few people to mine and smelt a small amount of copper,” he said. “And a few more to set up a wire-drawing operation. And, finally, tell your Scavengers to bring in some scrap copper wire. You won’t regret it, I guarantee.”
Then, after a pause: “Come on, Alf. You can’t make your way back to the modern world without putting electrical engineers in the front ranks. When you think of it, electricity is humankind’s most godlike exploit. In fact, maybe it’s the main reason the deities decided to send that comet our way. They looked down, saw us lighting up the night and bouncing radio signals off of artificial satellites; they must have thought to themselves, ‘Hey, enough is enough. Let’s cut these upstarts down to size.’ “
For the third time in as many days I found myself drifting into that fanciful world in which tales of past engineering achievements emerged as a key element of our own odyssey. First it had been iron and steel; then machine tools; and now, most marvelous of all, electricity. Damn it, Ruffin is right, I thought. You can’t help but agree with the guy, unpleasant as he may be: the mastery of electricity is indeed humankind’s most godlike exploit. And it is the means by which we can most decisively leap over centuries into the modern world. While Richards grudgingly negotiated the terms of a deal with the Electric Light Brigade, I started to jot down my personal thoughts in the margins of my minutes.
Later in the day, after the meeting was over, I went off by myself, intent on recording the ideas that had suddenly flooded into my mind. I skipped dinner, telling Sarah that I had some important work to catch up on. Seated with my back against a board I had half buried in the sand, looking out over Lake Mzingai, I scribbled away, carried off into a world of my own fancy. As night descended, I lit the candle that I carried with me whenever on secretarial duty, and the flickering light was an persistent reminder of how electricity had become central to our lives.
People have been fooling around with “static electricity” for a long time, at least since the ancient Greeks rubbed amber with fur and found that it attracted light objects such as feathers and lint. In fact, the Greek word for amber is
For me, the story begins in 1800, when Count Alessandro Volta made his electric pile, or what we today would call a battery. As the story goes, when Volta put a coin on top of his tongue, and a coin of a different metal under his tongue, his sense of taste led him to believe that something was “flowing” from one coin to the other. So he experimented with stacks of alternating discs of two different metals—zinc and copper, or silver and lead—with moist cardboard in between each slice. Then he ran a brass wire from one end of such a stack to the other and discovered that “something”—a current of electricity—ran through the wire.
Today, we know that electricity consists of the flow of electrons, and that metals, which characteristically have free-floating electrons in their outer shells, are good conductors of such flow. We also know that if we place zinc, with its thirty electrons, next to copper, with its twenty-nine electrons, then the electrons in the zinc “want” to move toward the copper, to equalize the situation, and thus they establish a flow of current. Such chemical generation of electricity is the basis of our batteries. But batteries are necessarily small. The large-scale generation of power depends upon other natural phenomena.
The next chapter in this remarkable saga features Hans Christian Oersted, a Danish physicist, who in 1820 gave a lecture that will live forever in the annals of science and technology. The topic was electricity, and for purposes of demonstration the professor had set up a circuit powered by a Voltaic battery. On his laboratory table, close to the electric wire, there happened to be a compass, an ordinary compass like those long used on ships to indicate the direction of the North-South magnetic field. Oersted noticed that each time he flipped a switch to start the flow of electric current, the compass needle quivered. Strange. Electricity in a wire was affecting magnetism in the surrounding air. Amazing. It seems that a flowing electric current creates around itself a magnetic force.
Well, then, if electricity can make magnetism, can magnetism make electricity? For awhile this question proved mystifying. People tried putting magnets over wires, under wires, surrounding wires, but nothing seemed to happen. The great Michael Faraday solved the problem in 1831. He demonstrated that by
So, by spinning a wire cage (called a rotor) inside of a magnetized casing (called a stator), we manufacture electricity. All we need is the power for twirling. This can come from a hand-operated crank, or more usefully, from turbines turned by falling water or by jets of steam. The steam, of course, can be obtained by burning coal or oil, or whatever.
We can then run the manufactured electricity—the magical flow of electrons—through wires and use it for lighting, or, among other things, to run motors. A motor is practically the same thing as a generator, except instead of spinning the rotor to make electricity, electricity is used to spin the rotor. It’s all so simple, in concept, anyhow.
The design of actual machines, of course, is not at all simple. Shortly after Faraday’s discovery of electromagnetic induction in 1831, a number of technologists started to fabricate small hand-operated generators. But it was not until 1873 that the Belgian engineer Zenobe Theophile Gramme built the first truly commercial electric machine. The alternating current motor of Nikola Tesla, which set the standard for worldwide use of electric power, was patented in 1888. What Tesla designed—and others after him—we can duplicate here in Engineering Village. As soon, of course, as we get Ruffin and his cohorts some copper wire.
While large-scale generation of electricity was being developed, other geniuses were gaining access to an even more wondrous mystery of the universe: electromagnetic waves that travel through space. Through space!
In the early 1860s, James Clerk Maxwell, a Scottish physicist, looked at the electricity-magnetism phenomenon from a new perspective. Since these two forces seem to create and modify each other, back and forth, over and over again—electricity makes magnetism, magnetism makes electricity—in an unending mutual propagation, one could perhaps infer that a wave was involved. After all, what is a wave but something that goes up and down, back and forth, over and over again? Maxwell theorized that when electrical oscillations are created, this generates waves: waves that travel through space. Not electrons moving through wires, but electromagnetic waves moving through space! It’s difficult to grasp the concept, and we really can’t come up with a satisfactory physical representation of these things. But the fact is that Maxwell developed mathematical formulas predicting the behavior of such waves, and these formulas were born out by experiment.
Physical confirmation of theoretical concepts was some time in coming. Maxwell published his wave theory in 1864, and it wasn’t until 1888 that Heinrich Hertz proved that electromagnetic waves actually did exist. He showed that they could be made in a laboratory, transmitted through the air, and received by an “antenna.” This was truly the greatest magic act of all time.
Using high-voltage electricity—which by this time could readily be produced—he created a spark between two coils. A few feet away, he set up a receiving mechanism consisting of two rods with a spark gap between them. As Hertz had hoped, the waves created by the first spark were detected, as evidenced by a spark appearing in the second gap.
The rest, as we never tire of saying, is history. Once it was shown that electromagnetic waves could be generated by mechanical means, and transmitted through space, it was only a question of time before the few feet became a few hundred feet, a few thousand, a few hundred thousand. In 1901, Marconi sent a radio signal across the Atlantic Ocean.
While sending and receiving these waves across long distances is marvelous, the question of utility arises. If all you can send is a spark, or a blip, you’re restricted to a Morse Code-type communique. On the other hand, if you can imprint lots of information on your wave—it’s called modulation—then you’ve done something very, very special.
This is what electronics engineers have been working on for the past hundred years, first with vacuum tubes, then with transistors and minuscule integrated circuits. Maxwell’s electromagnetic waves, imprinted with enormous
