Lightning

 January 04, 2021 ·  


Benjamin Franklin flew a kite in a thunderstorm, and then he proved. . . exactly what? For most Americans, that snippet of historical lore is about all they know of Franklin’s revolutionary work in science. It then becomes a guessing game: “He discovered electricity!”—not true. “He discovered lightning!”—clearly not true. “He discovered that lightning and electricity were the same thing!”—closer to the truth, but by itself not a truthful representation of the revolution that Franklin accomplished.

Why is it important, in January of 2021, to know what Franklin did? One clue is to carefully examine the stated intention of Joe Biden, if he does in fact succeed in occupying the White House. Biden has already declared his intention for the United States to rejoin the genocidal Paris Climate Accords; he has already announced a policy for the United States to have zero-carbon emissions by 2050; and it is very likely he will severely curtail or kill off Project Artemis, President Trump’s program to return Americans to the Moon. This already announced Biden agenda will halt all scientific progress and impose a death sentence on the nation, and ultimately on the entire world.

Benjamin Franklin, on the other hand, knew that a self-governing republic is impossible without scientific and technological progress and the ennoblement of the population to more skilled, more productive vocations. Mankind’s discovery of, and mastery of, new universal physical principles is the only basis for true human happiness.

Franklin achieved a revolution in science. Indeed, he became a key leader in fighting against the dead end of oligarchical “science” as promulgated by Isaac Newton, among others,—a methodology in which the universe remains a mysterious superstitious realm, where the principles which govern universal actions can never be known but only “observed” or “measured.”

The full story of Franklin’s deep involvement with anti-Newtonian scientific circles—including the Gottfried Leibniz-allied German network of Abraham Kästner, Erich Raspe and Gerlach Münchausen—is beyond the scope of this short offering, but for those who wish to pursue this subject a good starting place is Phil Valenti’s ground-breaking article “The anti-Newtonian roots of the American Revolution.” Here the focus shall be on Franklin’s scientific experiments.

Why Electricity?

Almost all biographies of Franklin state that he had no interest in electricity until 1746, when he attended an electrical demonstration by Archibald Spencer in Boston, and the next year received a glass tube and other equipment to conduct experiments from Peter Collinson, James Logan’s agent in London. However, this is clearly not the case.

In the first half of the 18th century, James Logan, Franklin’s patron and mentor, was the premier intellectual opponent of Isaac Newton and John Locke in the Americas. In his 1737 work Of the Duties of Man as they may be deduced from Nature, Logan excoriates Locke, Newton and Thomas Hobbes. Logan’s Platonic approach to science is seen in the fragment “Creative power of the Mind transcends the senses,” and his view as to the nature of Man is exhibited in “Love: ‘the principle which animates us to seek perfection’.” In Chapter 2 Of the Duties, Logan directly takes up the subject of electricity.

Logan says: “Electricity was formerly regarded but as a trifling appearance in Nature, and therefore in the last curious age was very little considered; for that quality was supposed to be excited, only by putting into motion the finer parts of the body it was found in, and yet the excellent R. Boyle has observed that these parts being put in motion, excited also the same quality in any other body, as Silver, Iron, Marble that was brought within the sphere of their action. But now more lately by F. Hawksbee’s Experiments in producing Light, and particularly by the surprising phenomena arising from Electricity in those of Geo. Gray, we may see a field open’d for Speculations, that if duly pursued, may probably lead us into more just and extensive Notions of our bodies, and the world we live in, than have hitherto been generally thought of.”

For Logan, the fundamental challenge was to discover the underlying principles of nature which govern certain phenomena, particularly light and electricity. Logan knew—and stated explicitly—that the behavior of both light and electricity contradicted Newton’s mechanistic theories. Logan postulated that investigations into the nature of electricity might lead to “more just and extensive notions…of the world we live in.”

Franklin, the protégé and later collaborator of Logan, studied all of these scientific debates. He personally aided Logan in some of his experiments regarding light and color, and became one of only a few scientists to support Christiaan Huygens’ wave theory of light. In a 1737 letter from Franklin to Logan, where Franklin comments on several sections of Logan’s Of the Duties of Man, it is clear that Franklin had carefully studied the work, including the section on electricity.

In the early decades of the 18th century there were a significant number of people in Europe investigating electrical phenomena. These included Christian Hausen, Georg Matthias Bose and Otto von Guericke in Germany; Charles Du Fay and Jean-Antoine Nollet in France; and Francis Hauksbee, William Watson, Benjamin Wilson and Stephan Grey in Britain. However, many of these individuals were content to use their knowledge to perform mere “parlor tricks” (such as the “shocking kiss”) for their aristocratic patrons. Even among the more serious, they all failed to understand what they were observing. They were stuck in a Newtonian approach which demanded that some “force” had to be driving the electrical current. This resulted in grave errors, such as the insistence of Jean-Antoine Nollet and Charles Du Fay that there were two distinct kinds of electricity, vitreous and resinous.

Franklin overturned the apple-cart. First, he insisted that all conclusions must be based on verifiable experimental results. Secondly, as Leibniz had done in the Leibniz-Clarke Debate, he denied Newton’s Deus Ex Machina of outside force and insisted that nature, rather than needing a push from God, operated according to inherent principles.

Franklin Intervenes

In 1746 Pieter van Musschenbroek, of Holland, invented the Leyden jar, a device which stores a high-voltage electric charge, essentially what is known today as a capacitor. That same year Peter Collinson, from London, sent Franklin a glass tube (with which to construct his own Leyden jar) as well as other paraphernalia needed to begin electrical experiments.

A Leyden jar is a glass jar, containing liquid, an outside metal jacket covering the glass and a wire dangling into it from the top. Through rubbing it, a static electrical charge is created in the bottle, with a positive charge on the outside of the bottle, and the negative charge on the inside. To restore the equilibrium, all you have to do is hold the jar and touch the wire (which produces a shock), creating a circuit that equalizes the charges. Up until Franklin’s experiments no one could explain why this occurs.

Over a span of 4 ½ years Franklin conducted hundreds of experiments and constructed dozens—if not hundreds—of experimental devices. He would develop a theory, test it, and if it was proven false, he would move on to the next hypothesis. He describes this, “In going on with these experiments, how many pretty systems do we build, which we soon find ourselves obliged to destroy! If there is no other use discovered of electricity, this, however, is something considerable, that it may help to make a vain man humble.”

One of his first conclusions was that electrical current was a type of energy which permeated all of nature. He called this “electrical fire.” He refuted the idea that there were two different species of electrical currents, and showed that it was one phenomenon, which differed only in its internal make-up, differences which he called positive and negative charges. The interaction of the two charges produced a reaction which reorganized the electrical state of the host. Thus, he discovered electrical “ionization” and essentially “electron theory,” even though he had no means to see within the atom. Refining the Leyden jar and using other devices he invented, Franklin spent months investigating the properties of electrical charges.

He studied the attraction and repulsion of charges. He hypothesized that electricity doesn’t vanish but that is always present in the same amount (the “conservation of energy”). Others in Europe had insisted that electricity “moved” from point A to point B, as a result of some invisible force moving it. Franklin showed that the electricity did not “move” at all, that it was always present everywhere. Only the electrical charge changed, a phenomenon which human intervention could replicate.

Franklin solved the mystery of the Leyden jar. He proved that the electrical charge in a Leyden jar which produced the “shock” resided not in the water in the jar but the glass itself, and that the Leyden effect was just the reorganization of the jar’s internal electrical configuration. He stated “there is really no more electrical fire in the phial after what is called its charging, because the phial will not suffer what is called charging, unless as much fire can go out of it one way, as is thrown in by another. . . So wonderfully are these two states of Electricity, the plus and minus, combined and balanced in this miraculous bottle!”

He also demonstrated that electricity could be transmitted, through the air. He postulated that electricity was composed of extremely “subtle” particles which were suffused throughout nature and could penetrate even the densest of matter. He was now poised to investigate whether his laboratory research could be replicated on a larger scale, to investigate electrical phenomena in the atmosphere.

The Unenviable Sentry

Franklin postulated that lightning was simply a type of electrical phenomenon. He was not the first to suggest this, but he was the first to prove it. In his work with the Leyden jar and other devices, Franklin had perfected the ability to “draw off” an electrical charge from various charged objects. Twice, in these experiments, Franklin had been knocked unconscious. He now proposed to “draw off” an electrical charge from the atmosphere.

In 1750 Franklin proposed an experiment, what later became know as the Sentry Box Experiment. This is how he described it:

“To determine the question, whether the clouds that contain lightning are electrified or not, I would propose an experiment to be tried where it might be done conveniently. That is:

“On the top of some high tower or steeple, place a kind of sentry box big enough to contain a man and an electrical stand. From the middle of the stand let an iron rod rise, and pass bending out of the door, and then upright 20 or 30 feet, pointed very sharp at the end. If the electrical stand 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 the cloud.”

The intention was not to draw an electrical charge from lightning itself, but from the ionized clouds in the upper atmosphere.

It seems apparent that Franklin did carry out this experiment, but the details of it were never recorded. Then, in May, 1752 Jean Francois Dalibard, using a description of the experiment published in Franklin’s 1751 Experiments and Observations on Electricity, replicated the experiment successfully in France. A week later a second Frenchman, de Lor, recapitulated the test, with similar results. Within months the experiment was being tried all over Europe. One unlucky sentry, Georg Wilhelm Richmann of Sweden, was killed when he conducted the experiment in a severe thunderstorm, and a lightning bolt struck the iron rod protruding from the roof, electrocuting him instantly.

It was out of these experiments that Franklin invented the grounded lightning rod, the first two of which were erected on the Pennsylvania State House and the Pennsylvania Academy.

The Kite

In 1749 Franklin had published an essay describing the electrification of clouds, rising off the sea in hot weather and then discharging their energy by way of thunderstorms. He postulated that electricity is a universal property of nature and the universe. His theory was that lightning was a particularly powerful phenomenon produced by an ionized gaseous substance in the upper atmosphere. Essentially what he describes are the properties of what today we would call a plasma.

Then, in June 1752, Franklin set off with his son William to test his hypothesis. He had a specially constructed kite made of silk: “Silk is fitter to bear the wet and wind of a thunder gust without tearing,” he explained. The wooden frame was made of cedar. Hemp twine would run from the kite to the ground. Dry, hemp conducted electricity moderately well; wet, it would “conduct the electric fire freely.” At the ground a large key was to be tied to the twine; this would absorb the electric charge that ran down the string. A silk ribbon would be attached to the string at the bottom to insulate the flyer’s hand from the wet twine and key.

Franklin and son launched their kite; it soared toward the base of a cloud. Joseph Priestly describes what happened next:

“He observed some loose threads of the hempen string to stand erect, and to avoid one another, just as if they had been suspended on a common conductor. Struck with this promising appearance, he immediately presented his knuckle to the key, and (let the reader judge of the exquisite pleasure he must have felt at that moment) the discovery was complete. He perceived a very evident electric spark. Others succeeded, even before the string was wet, so as to put the matter past all dispute, and when the rain had wet the string, he collected electric fire very copiously.”

Note that the kite was not struck by lightning. It collected the electrical charge from within the ionized atmosphere. In the Autumn of 1752 Peter Collinson published news of Franklin’s kite experiment in London, and his fame spread throughout Europe. In 1753 Franklin’s close collaborator Giambatista Beccaria reproduced the kite experiment in Turin.

Next, Franklin duplicated the experiment, this time attaching the end of the twine to a Leyden jar, to see if he could use the charge he was drawing from the atmosphere to electrically charge the jar. He succeeded at this as well. He “drew lightning from the heavens.” He wrote a letter to Collinson, describing, “making a Machine or Kite,” that, when flown in a thunderstorm, would draw “Electric Fire from the Clouds to such a degree as to charge a Phial, kindred Spirits, and to perform all the other Experiments which are usually done by rubbing a Glass Globe or Tube, and thereby the Sameness of the Electric matter with that of Lightning may be demonstrated.”

There is another matter to consider. What Franklin proved is that lightning does not, in fact, “strike the earth,” at least not in the way that most people think about it today. Rather, he showed that thunderclouds are negatively charged and that the ionized charge in the clouds reacts with a positive charge, either on the ground or from another cloud. In other words it was the same phenomenon of positive and negative charges interacting which he had observed in the Leyden jar experiments.

Universal Truths

In 1751, in a letter to his sometimes collaborator Cadwallader Colden, Franklin directly challenged Newtonian orthodoxy, proposing that “Universal Space [is] filled with a subtle elastic Fluid.” Through his experiments with electricity Franklin became convinced that “electric fluid” was “pretty equally diffus’d in all the Matter of this Globe.” He goes on to say, “Perhaps the Aurorae Boreales are Currents of this Fluid in its own Region above our Atmosphere, becoming from their Motion visible. There is no End to Conjectures. As yet we are but Novices in this Branch of Natural Knowledge.”

After 1751, Franklin’s electrical experiments tapered off. He was now drawn to a larger field of combat. He was elected to the Pennsylvania Assembly; he established the Pennsylvania Hospital, the first hospital in the 13 colonies; and in 1754 he headed the Pennsylvania delegation to the Albany Congress, and there put forward his “Plan of Union” for autonomous self-government of the colonies. Then in 1757 he was sent to London as the representative of the Pennsylvania Assembly.

Franklin was now embarked on his next great experiment, one that would result in the creation of the first self-governing democratic republic in human history. We close with an epigram from Cato, a favorite of Franklin, and one he quoted often:

Here will I hold—If there is a pow’r above us
(And that there is, all Nature cries aloud,
Thro’ all her Works), He must delight in Virtue
And that which he delights in must be Happy.