The Electron: A Biography and the Emergence of Soldering

The electron’s story traces how discoveries in electricity and electromagnetism helped drive the development of telegraphy, telephones, electric lighting and soldering.
by Ronald C. Lasky

Folks, the following post is some of what I presented at SMTA PanPac February 2-6, 2026 with a little of the history of soldering added.

My interest in the history of electronics was piqued when I attended a mid-1990s lecture by Nobel laureate Arno Penzias on the same topic. Penzias was a co-discoverer of the cosmic microwave background, which strongly supports the Big Bang creation theory of the universe.

A striking feature of Penzias’s talk was when he said: “In 1972, one megabyte of computer memory cost $1 million. That is about what a small apartment building, in New Jersey, cost back then. Today (1994), a megabyte of memory could not buy a hinge on a door in the apartment building.”

Wow, what a striking statement! I often return to this thought when thinking about the rapid advances in electronics. These advances have led to today’s $1,000 smartphone having several times the computing power of the fastest supercomputer of 1995 and more than the computing power of all supercomputers of 1990. But I’m getting ahead of myself.

Let’s start with a simple question: What defines modernity? The smartphone? TV? The internet? The electric light? I think the answer is simpler: Electricity. Electricity enables it all.

But let’s start at the very beginning: the birth of the electron.

The most useful particle in physics – the electron – was born about 13.8 billion years ago, in the first moments after the Big Bang. It emerged alongside roughly 10^80 fellow electrons and an equal number of protons, the raw material from which all ordinary matter would eventually form. Over billions of years, that matter condensed into as many as a trillion stars in the observable universe. So vast is this number that if every star were represented by a single grain of sand, the grains would blanket the entire Earth to a depth of about a meter.

Figure 1 shows a deep space image from the James Webb telescope. The small red galaxies formed less than a few hundred million years after the Big Bang. Therefore, we are seeing the galaxies a short time after they formed. They contain the youngest electrons ever seen. The galaxies are red because they are redshifted as they speed away from us.

Humans would not learn to exploit the electron until 1820. But it would be a mistake to minimize this diminutive particle’s role in everything that came before. All matter in nature is held together by electrical force, from the smallest virus to the most massive star; without the electron’s properties, nothing material could exist.

Serious experimentation with this mysterious force didn’t begin until 1752. That summer, Benjamin Franklin flew a kite into a Philadelphia thunderstorm and showed that lightning and the static electricity raised by rubbing a glass rod were one and the same. It was one of the earliest instances of real science conducted in America, and it feels like a fitting place to begin our story: someone brave, or foolish, enough to reach out and touch the electron’s power directly, decades before anyone understood what was actually being touched.

Why is 1820 important? It was, in that year, by accident, that Hans Christian Ørsted made the discovery that led to useful applications of electricity. He was giving a public science lecture at the University of Copenhagen on the heating effects of electricity. He was using a battery, invented in 1800 by Volta. During the lecture, Ørsted was surprised that when a compass was held near a wire in which current was flowing, the compass needle was deflected. This discovery showed that electricity and magnetism were related. Subsequent work by André-Marie Ampère, Michael Faraday, and eventually James Clerk Maxwell led to the codification of electromagnetic (EM) theory into Maxwell’s Equations by 1865. These equations have not been improved upon today and are the foundation for the design of essentially all electrical devices.

Soldering was older to Julius Caesar (100–44 BCE) than Caesar is to us. The earliest evidence of soldering dates to about 3500 BCE, making the technology more than 3,400 years old in Caesar’s lifetime. In contrast, pioneering electrical researchers such as Hans Christian Ørsted and Michael Faraday relied primarily on temporary electrical connections rather than soldered joints. They commonly used binding screws, clamps, twisted wires or even mercury cups, into which they immersed the ends of wires to make reliable but easily reconfigurable electrical connections during their experiments.

The Telegraph, Telephone and Electric Light

However, well before Maxwell’s Equations in 1865, inventors were putting electromagnetism to work. One of the first inventions was the telegraph. Samuel F. B. Morse perfected it and chose the founder of my alma mater, Ezra Cornell, as a partner to implement it. It would be difficult to overstate the importance of the telegraph. With the railroad and photography, it made the American Civil War the first modern war. President Lincoln was a regular at the Washington, DC, telegraph office, using telegraphy to direct the war, far from the battlefields. The Union’s use of trains to transport troops and supplies was unprecedented and far outstripped the South’s capabilities. The North’s use of these two modern tools helped secure its victory. Meanwhile, photographers like Mathew Brady brought the horrors of war home to the people.

The invention of the telegraph gave birth to electric soldering, as wires and components now needed a permanent bond. Tinsmiths of the day performed the soldering using techniques they had developed. Tin-lead solder of 60/40 composition, close to the 63/37 formulation most recently phased out of the commercial world, was used. Soldering irons were made of a copper block shaped to a point and heated in burning coals, much like a blacksmith’s tools. Electric soldering irons did not arrive until the 1890s. Solder in bar or wire form was used as shown in Figure 3 and Figure 4.

Thomas Jefferson once mused that, given how enormous the Louisiana Purchase was, it would take 25 generations to settle it. He could not have been more wrong. And the telegraph played a part.

The telegraph’s true impact emerged when it married the train in the transcontinental railroad. The railroad men pleaded with Congress for money to build the line from sea to shining sea, claiming they could not do such a massive undertaking without government financial help. A pliant Congress agreed, but only if the railroad would install telegraph lines alongside all the rail tracks. The transcontinental railroad was finished in 1869 to much fanfare and had a stunning effect on the development of the American West.

The “49ers” traveling from New England needed up to 8 months to get to the California gold fields. By 1870, the trip could be made in 4 days, and a telegraph message could reach friends and family instantly, letting them know you were coming. Never in history has change been so dramatic. In 1850, it could take months to get a message from New York City to San Francisco. In 1870, minutes.

By 1877, the theory of electromagnetism saw its first practical application in a telephone line from Boston to Somerville, MA, a distance of three miles. By 1900, there were close to 1.5 million phones in the United States. Telephones increased the demand for soldering. By this time, soldering with solder wire and an electric soldering iron was becoming more common.

We could overstate the importance of telegraphy and telephony as compared to electric lighting. In the mid-1800s, whale oil was often the best choice for home lighting. It burned clean and bright, but stank and cost hundreds of today’s dollars per month. Kerosene was a welcome replacement, especially with John D. Rockefeller’s Standard Oil. But inexpensive electric lighting replaced all of these stinky and dangerous lighting technologies. The implementation of electric lighting set off the War of the Currents: Edison versus Tesla and Westinghouse, so well documented in a motion picture, “The Current Wars.” Spoiler alert: Tesla’s AC current won. All of these advances created the need for more and more soldering with solder wire and soldering irons.

Meanwhile, Back in the Lab…

While Edison, Tesla and Westinghouse were busy wiring up cities and fighting the War of the Currents, something curious was happening a few steps behind them: nobody actually knew what an electron was. As late as 1895, most physicists still thought of electricity as some kind of fluid, sloshing through wires like water through a pipe. Engineers had been soldering telegraph lines, stringing telephone cables and lighting entire cities for the better part of 50 years without anyone being able to say, with any confidence, what was actually flowing through the wire.

That changed in 1897, when the English physicist J. J. Thomson, shown in Figure 5, built a modified cathode ray tube, illustrated in Figure 6, and showed that the mysterious “cathode rays” streaming inside it were actually a stream of individual particles, each carrying a negative charge and possessing only a small fraction of the mass of a hydrogen atom. Thomson’s method was elegant: he first balanced electric and magnetic forces to find the particles’ velocity, then balanced the magnetic force against the centripetal (mechanical) force needed to curve their path, allowing him to calculate the particles’ charge-to-mass ratio, e/m. For the first time, humanity had proof that electricity was not a fluid, but a stream of discrete particles. Thomson had discovered the electron.

 

Thomson could measure the electron’s charge-to-mass ratio, but he could not isolate the charge or the mass alone. That took another thirteen years and a rather cleverer piece of glassware. In 1910, American physicist Robert Millikan sprayed a fine mist of oil droplets between two charged parallel plates, as shown in Figure 7, and adjusted the electric field until it exactly balanced gravity, leaving individual charged droplets suspended in mid-air. By carefully measuring the field needed to hold each droplet still, Millikan found that the charge on every droplet was always a whole-number multiple of one fixed, tiny amount: the elementary charge, e. The electron finally had a measured identity, a mass, a charge, and, for the first time, a name that meant something specific and real.

It is a fun bit of irony that the practical engineers of the 19th century were decades ahead of the physicists. The telegraph, the transcontinental railroad, the telephone, and the electric light bulb were already reshaping the world before anyone could prove, in a laboratory, that the electron even existed as a distinct particle. Practice, it turns out, does not always wait for theory.

Now that science had finally caught up with engineering, and given this little particle a name, a mass, and a charge, it was time for the electron to be put to work in a whole new way. Next time, we’ll see it amplifying whispers into a roar, inside a simple glass tube, and giving birth to radio.End of article content

Ronald C. Lasky, Ph.D., P.E., is a senior technologist at Indium Corporation and a professor of engineering at Dartmouth College.