How Jealousy Led to the Battery

About 180 miles away from Galvani in the beautiful area of Como, Italy, the anatomist friends of Italy’s greatest electrical scientist at the time, Alessandro Volta, was informing him of Galvani’s great discovery.   

Volta was a sophisticated world traveler who was known as, “a genius who swore and cackled over his experiments, guzzled and disputed over his dinner, electrified the ladies…and understood more of electricity than anyone else in Europe.”   He also first came to fame in 1775 by, basically, stealing another person’s invention, an object that Volta called “the electrophorus”.  [Most biographies put it more politely than that and say that Volta “promoted” the invention until several people thought it was his own].  In the following years, Volta made several discoveries that are not attributed to other people, like discovering methane and creating and studying different configurations of Leyden jars.   

Leyden jars
Leyden jars

In 1792, Volta began to repeat Galvani’s work and found the results “unbelievable” and “miraculous”.  Volta then got a live frog to jump with two different metals attached to each other and to the frog’s leg and back.   This was astonishing as he was demonstrating that Galvani was not re-animating the frog, as even an animated (ie. live) frog would move if in contact with dissimilar metals.  Volta decided that the electricity came from the different metals and the frog was merely responding to the electricity produced by the metals, just as it jumped from the electricity from machines and from lightning bolts (Volta did not think about any chemical action of the acids in the frog or the operator’s hands).   Volta felt that he had destroyed Galvani’s claim that animals have electricity within them.  “Nothing remains of the theory of animal electricity,” Volta combatively wrote in an open letter in 1793.  Quickly, the scientists of Italy and Europe began a battle between the Voltists and the Galvanists. 

Galvani, however, was not really a good debater on the Galvanist’s side as he had basically retired from public talks after the death of his wife and, as far as I can tell, was not a combative person anyway.  Instead, he left the argument to his nephew Aldini.  Aldini, despite being a professor of Physics, was much more of an entertainer than a scientist.  For example, he liked to do public demonstrations twitching the eyes or mouth of a cow’s head and even a human head of a decapitated criminal.  This, for obvious reasons, gained the public’s attention.  He even went to London and inspired a young woman named Mary Shelley who wrote a story in 1818 called “Frankenstein”.  However, these dramatic displays did not help much in academia, “for the world of sober science, Aldini had in effect given over the laurel to his uncle’s rival.”

One can see that Volta (and the Voltanists) were winning by the fact that in 1794, Volta won the Copley Medal, a prestigious British award for “for his several communications explanatory of certain experiments published by Professor Galvani”. Volta won this award despite the fact that Volta, in 1794, had done far less experimentally than Galvani had, and had come to less interesting conclusions.  Volta was unhappy: he wanted to win awards for discoveries attributed to him not for explaining Galvani’s work!

Volta
Volta

Volta needed a decisive experiment.  Something that would prove that electricity came from the metals and not the frog.  However, the only sensitive electroscope he had was a frog’s leg so he was in a bit of a quandary – to prove his thesis, he needed a more powerful system with only inorganic materials.

The first thing Volta did was to determine which metals worked the best on the poor frog and found that silver and zinc seemed to have the greatest effect.  If he put a piece of silver and zinc in his mouth he would feel a slight tingle, but if he connected the silver and zinc to wires and put the wires on his tongue, he felt nothing.  Volta started to wonder if the metals had to be wet. Therefore he put wet thin cardboard between a pair of silver and zinc disks.  Suddenly, there was enough voltage to be noticeable on his tongue!   Moreover, you could get more tingling by just adding more disks (and by using saltwater instead of plain water).  Here was a non-organic object that would create continual electricity with no rubbing or moving plates required.  In fact, Volta had just invented the battery!  He published his work in 1800 to tremendous acclaim.

Of course, Volta did not actually call his device a battery, he preferred the linguistically awkward term: “artificial electric organ”.  In fact, “a battery” was what Ben Franklin called a set of Leyden jars used simultaneously, the most powerful electrical device at the time.  However, Volta said that his apparatus resembled, “an electric battery,” several times in his paper, which is why it was sometimes called just that: “an electric battery”.

Now, mind you Volta’s battery could give a small shock and whereas a battery of Leyden jars could kill a small animal.  He even admitted as much, “my new instrument, which as I have said, imitates the effects …of electric batteries… is far inferior to the activity of these batteries when highly charged…. In other respects, however, it far surpasses the virtue and power of these batteries, as it has no need…[to be] previously charged by means of foreign electricity, and as it is capable of giving a shock every time it is properly touched, however often it may be.”

How does it work?  We now think that the acid in the saltwater reacts chemically with the metals to move electrons from the silver to the zinc leaving the zinc with a negative charge (as electrons are negative) and the silver with a positive charge.  If you connect the silver and zinc with wires to your tongue the electrons in the zinc will run in a current to the silver and cause your tongue to tingle.  They will continue to do this until the acid becomes neutralized, or the silver gets coated with hydrogen gas. 

How about the frog?  Well, the acid in the frog has chemical reactions that take electrons from one metal (copper) and put it in another (iron railing) leaving the copper negatively charged and the iron positively charged.  Electrons then flow through the muscle of the frog from the copper to the iron, which makes the muscle contract.  All batteries even today use the chemical reaction of an acid or a base with two different metals to make a positive and a negative side.  If you want to know more about how modern batteries work, check out my video elegantly titled “How Batteries Work”.

Back in 1800, Volta’s victory was complete.  He demonstrated his new device to Napoleon in 1801 who made him a count in 1810.  The potential of a battery is measured in Volts (named after him) and is often referred to as Voltage in his honor.  He won many awards and retired a wealthy man, never to do anything else worthy of publishing again until his death at age 82 in 1827.  Interestingly, in his famous paper of 1800, he still found time to insult his old rival Galvani who had died two years earlier by writing that his research was motivated because, “I found myself obliged to combat the pretended animal electricity of Galvani, and to declare it an external electricity moved by the mutual contact of metals of different kinds.”

I do not mean to diminish Volta’s accomplishment.  The battery truly revolutionized not only the fields of Physics but also Chemistry and Biology. In Biology, ironically enough, the battery was instrumental in the study of how muscles and nerves use electricity to function in animals.  Interestingly, in Biology, they called that study Galvonics and sometimes called the battery a Galvonic Battery instead of a Voltaic Battery.  In Physics, the battery was the launch to understanding the world around us and towards creating the electrical devices that we are so addicted to today.  

One of my favorite little stories of the power of Volta’s battery is what is called the “Oxford Electric Bell”.  The Oxford Bell uses two large Zamboni pile batteries (which are like Voltaic piles except with thin pieces of paper coated with silver and zinc instead of separate discs of silver, paper, and zinc) connected to two bells with a small metal sphere hanging between them.  The bells are positive and negative respectively as they are connected to the positive and negative sides of the battery.   The neutral sphere is then attracted to one side and then when it touches, gets some of that charge to be repelled and attracted to the other side. Ben Franklin did a similar demonstration with a ball on a string vibrating between two Leyden jars.  However, Franklin could get his to “ring” for a couple of days and the Oxford Electric bell has been “ringing” continuously since at least 1840 – approximately 10 billion rings – with the same battery!  It will eventually stop, but we have no idea when.  

It is such a shame that there had to be a “winner” in this debate because in a fundamental way they were both correct.  I think that the portable defibrillator is an example of the perfect marriage of the power of both men’s philosophies.  First, when a person turns on a portable defibrillator (which they call “charging it up”) they connect a battery to a large capacitor.  The battery is simply composed of two different metals with a battery acid between them.  The capacitor is basically a version of a Leyden jar, two metal plates with an insulator between them, but rolled up like a lollypop to save space.  This part is 100%, Volta.  Then, the EMTs put metal paddles on the patient’s chest (sometimes with a gel to make the electricity flow easily from the paddles into the patient’s chest), yell “clear”, and flip a switch to connect the paddles to the sides of the capacitor.  A huge rush of electricity flows through the patient and, hopefully, after that, the patient’s heart will beat again.  That flash of life is pure Galvani. 

A surprising branch of science to flourish with the battery was Chemistry.  See, it turns out that if you have a liquid compound and you connect the leads of a battery to it, it can decompose into its different components.  In 1801, this was used to show that water was composed of Hydrogen and Oxygen!  The master of this technique was an Englishman named Sir Humphrey Davey who

used electricity from batteries over a period of just two years in 1807 and 1808 to isolate and discover eight new elements (increasing the total number from 39 to 47).  Davey is a fascinating fellow, famous for his wit, good looks, and poetic descriptions of Chemistry.  He also made the first commercial electric light.  However, he never would have been anything but a country doctor if he hadn’t done drugs.  Lots and lots of drugs.  And that story is next time on the secret history of Electricity.

How doing drugs led to fame and the first commercial electric lamp.

Davy eloquently said, “Volta has presented us a key which promises to lay open some of the most mysterious recesses of nature.”

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