Why would inventing a motor irritate anyone? And how did Faraday invent the motor in the first place? Well, I’ll tell you and along the way I will talk about a strange theory of spiraling currents, a misunderstanding of electromagnetic forces, and a useless motor.
Table of Contents
Oersted’s Experiment Explained
Faraday’s Electric Motor
Michael Faraday and Humphry Davy’s Work Relationship
Humphry Davy’s Death
Oersted’s Experiment Explained
In 1820, a Danish man named Oersted made a remarkable discovery. When current runs through a wire it can make a compass point in a circle around the wire! Now a compass is just a thin magnet on a pivot, so Oersted had proved that electricity and magnetism are linked. What was incredibly confusing to people was that the current went a straight line and the magnets made circles around the wire.
Oersted’s solution was that maybe the current was really spiraling down the wire. He even made it more complex then that, where a positive current spiraled one way and moves the north end of the compass and a negative current spiraled the other way and moves the south end of the compass! Whew.
This brings us to England and men named Michael Faraday and his mentor Humphry Davy. Humphry Davy was a famous Chemist and laughing gas aficionado who was arguably the most famous scientist in all of Europe at the time.
Eight years previously, Davy had injured his eye and hired Michael Faraday, a young, uneducated and poor bookbinder’s apprentice as his assistant. By 1820, Davy was promoted to president of the Royal Institution of London and Faraday had been promoted to the position of “Chemical Assistant” and was conducting some of his research independently of Davy.
Both Davy and Faraday (and frankly, every other scientist in Europe) heard about Oersted’s experiment and tried to figure out what it meant. Davy wrote his brother that, “I have ascertained (repeating some vague experiments of Orsted’s) that the battery is a powerful magnet…I am deeply occupied in this.” Notice that Davy got an important fact wrong about Orsted’s experiment.
The battery is not a magnet! It is tempting to think it must be as it often is in a similar shape to a bar magnet and the + and – signs seem so similar to the N and S of a magnet. In fact, the battery isn’t magnetic, but the current in the wire is. In April, Davy collaborated with his friend William Wollaston in this problem.
Wollaston had agreed with Oersted that the current must spiral down the wire. They spent many hours trying to come up with an experiment to demonstrate this spiraling motion, but to no avail. Supposedly, Faraday heard some of their discussions but never found them interesting enough to put in his notebook.
Faraday’s Electric Motor
In the summer of 1821, Faraday was asked to write a review of the latest developments in electricity for a journal. Through painstaking experiments, Faraday determined that the wire wasn’t attracting either end of the magnet but instead orienting the entire magnet. He also determined that the force was purely circular around the wire not spiraling as Oersted thought. He decided that, strange as it may seem, the current seemed to travel straight down the wire and somehow it made a circular force on a magnet around the wire. In return, Faraday also postulated that a magnet also made a circular force on a wire around it. In other words, “a wire ought to revolve round a magnetic pole and a magnetic pole round the wire”.
Faraday began looking for a way to demonstrate that a current-carrying wire will feel a force in a circle around a magnet. On September 3rd, 1821 he created a simple experiment in his laboratory to demonstrate this force. He had a wire drop down on a cup full of mercury (mercury is a conducting fluid) with a permanent bar magnet in the center. When he closed the switch the wire spun continuously. Supposedly, Faraday shouted, “There they go! There they go! We have succeeded at last!”
Technically, Faraday had just invented the electric motor as an electric motor is a device that changes electrical energy into motion. Of course, it wasn’t a particularly practical motor as it didn’t do any useful work (unless you want to electrically stir mercury). Luckily, Faraday didn’t invent the motor to do any work. He invented it to demonstrate that the current moves straight down the wire and the magnetic force is circular around the wire. As a motor, it was useless, as a demonstration of the nature of magnetic fields, it was quite efficient.
Michael Faraday and Humphry Davy’s Work Relationship
Faraday published his work on October 1st, 1821 to great acclaim. But within a week, he heard rumors that people were saying he plagiarized his material. The person shouting the loudest was his former boss and mentor, Humphrey Davy!
Faraday wrote to Wollaston, “I am anxious to escape from unfounded impressions against me, and if I have done any wrong that I may apologize for it.” Wollaston wrote back and claimed to be unoffended; “you have no occasion to concern yourself much about the matter.” However, Wollaston didn’t publically defend Faraday and Davy publically attacked him.
It is hard to know, almost 200 years after the fact, why people did what they did and how they felt about it. Most modern researchers feel that Davy was jealous of his protégée’s success and felt that Faraday was too low class and uneducated to be an independent researcher. Davy was from a middle-class background but had been knighted as a baron in recognition of his scientific work.
Therefore Davy might have been class conscious in a way that a person who has risen far from middle-class beginnings could be. However, it is also possible that Davy felt justified in his anger. Faraday was a person that Davy had plucked from obscurity and he did not give credit to his benefactor.
And it is true that Davy and Wollaston had been trying to make a spinning device before Faraday did (although with a different motivation). Finally, it isn’t clear that Davy really understood what Faraday was proving with his experiments. Davy’s brother stated that his objections to Faraday were “an act of justice to Dr. Wollaston”, and it is quite possible that Davy felt that way for the rest of his life.
Humphry Davy’s Death
In May of 1823, Faraday was nominated to be a fellow of the Royal Institute to the strong objection of Davy (the secret vote was nearly unanimous with only one dissenter, probably Davy). In 1826, Davy fell very ill from using too much laughing gas or from inhaling dangerous chemicals in the laboratory and resigned from his job as a Chemist. Davy passed away three years later.
Meanwhile, Faraday was eager to continue his studies of electricity but instead, he was basically forced by the government to study how to make better optical glasses (a study that he found particularly fruitless, stating that the only results were his own “nervous headaches”). Therefore, Faraday was unable to return to electricity until 1831.
The first person to really take Faraday’s idea to the next level was a newly retired soldier and bootmaker named William Sturgeon. Sturgeon actually invented one of the first practical motors in 1834. First, however, he focused on another thing Faraday mentioned in his paper, that a helix of wire acts like a bar magnet. How Sturgeon invented the first practical electromagnet is next time on the secret history of electricity.