The Inventions of Thomas Alva Edison Content from the guide to life, the universe and everything

The Inventions of Thomas Alva Edison

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Said to be 'the most respected technologist of the time', Thomas Edison defined genius as 'one percent inspiration and ninety-nine percent perspiration'. Deaf from an early age, he never seemed to mind the disability since it helped him to concentrate on his work. Taking naps instead of sleeping at night, he believed that sleeping was a waste of time and 'a deplorable regression to the primitive state of caveman'. All this hard work paid off; by the time he died (1931), he had patented 1,093 inventions.

Edison was born in 1847 in Milan, Ohio. At the age of 22 he went to New York and started selling newspapers. Later on he became publisher of his own newspaper, the Weekly Herald.

Stock Tickers (1869)

Edison easily gained a reputation as being an innovator and inventor. When a new telegraphic machine that showed gold prices at New York's Gold Exchange broke down, Edison was called in to fix it. Not only did he do that, but he also improved it so that the changes in the prices could be registered automatically. Edison's first large sum of money was earned from this project. As Edison recalled:

[General Marshall Lefferts] called me into his office and said: 'Now, young man, I want to close up the matter of your inventions. How much do you think you should receive?'
I had made up my mind to that, taking into consideration the time and killing pace I was working at, I should be entitled to $5000, but could get along with $3000. When the psychological moment arrived, I hadn't the nerve to name such a large sum, so I said: 'Well, General, suppose you make me an offer.'
Then he said: 'How would $40,000 strike you?'
This caused me to come as near as fainting as I ever got. I was afraid he would hear my heart beat. I managed to say that I thought it was fair.
'All right, I will have a contract drawn; come around in three days and sign it, and I will give you the money.'

This incident increased his popularity as an inventor and greatly influenced his career.

The Multiplex Telegraph (1874)

After Edison had established himself, a rival of his, JB Stearns, beat him to creating the duplex telegraph, but Edison was still working away at a better model and 'never tired of working on the telegraph'. This improved version would be able to send four messages at a time on a single wire. The way Edison thought to achieve this was by combining the duplex telegraph (sending and receiving a message simultaneously on the same wire) and the diplex telegraph (sending or receiving two messages in the same direction on the same line). It was a 'combination of sounders, circuits, condensers, batteries, and relays that only a truly scientific and ingenious mind could construct'.

At the time that Edison was completing this project, he had been working for two different companies: Western Union and the Automatic Telegraph Company. Since both companies knew that whoever owned this invention would dominate the industry, they went to court for seven years over the matter of ownership of this product.

Although Edison never received payment for this invention he made a successful demonstration of it on 9 July, 1874, and a press conference was held to announce this accomplishment.

This invention of Edison's was later useful when the invention of the telephone came around. Many of the ideas used in this invention were also applicable to the telephone.

The Telephone Transmitter (1877)

Shortly after Alexander Graham Bell's invention of the telephone, the President of Western Union, William Orton, hired Edison to create a better version of the telephone. Working for $150 a week, Edison worked on improving the telephone's transmitter for five years, eventually causing the speaker's voice to sound louder and clearer. Edison started out by trying to find a substance that would convert the sound of the voice into electrical current more clearly. Some of the substances he tried were sponges, moist paper, felt, graphite, quicksilver, cork, lead, mercury, and over 2000 other substances but eventually he used tiny particles of carbon. The granules were kept in a small container and were pressed together by the sound waves of the voice causing the amount of electric current to vary depending on how loud the voice was. Edison had come up with 50 different telephones before he came up with one that he was satisfied with. It was successfully tested between New York and Philadelphia and was an immediate, widespread success and is still used today. Edison's telephone transmitter has changed little since the time of its invention. It is an invention that has stood the test of time.

The Phonograph (1877)

One of Edison's most famous inventions (as well as his personal favourite) is one of his early ones, the phonograph. In August of 1877, Edison was working on a telegraph invention and noticed that when he ran the machine very fast it made a musical sound. Intrigued by this, he set out to find out why it made the music and by the end of the day he had figured it out. Also that day, Edison came up with the idea for the phonograph, 'a machine that will record the human voice and reproduce it again whenever I want it to, just as this machine records and reproduces telegraph messages!' Edison exclaimed. He was so excited by his new idea that he stopped work on the telegraph machine he had been working on and concentrated all his energy into his new invention. A few days later he gave one of his assistants, John Kruesi, a sketch of the machine he had thought up and told him to make it. When the model was finished it consisted of two small horns, one being the mouthpiece containing a diaphragm to which was attached a tiny stylus that rested on the tin cylinder. Recording was done by cranking the cylinder and talking into the mouthpiece simultaneously, causing the stylus to vibrate and trace a bumpy path on the tinfoil. To play back the recording, the mouthpiece was swung out of the way and replaced by a much lighter diaphragm and stylus that followed the groves in the tinfoil as the crank was turned and reproduced the voice. All this was built on a budget of $18.

When Edison first tried out his 'talking machine' in his laboratory, all his assistants were amazed and wanted to try it. Edison himself confessed, 'I was never so taken aback in my life. I was always afraid of things that worked the first time'. Edison's phonograph was later advertised in Scientific American, and Harper's Weekly gave it a full page spread with illustrations, including a list compiled by Edison of ten major applications his sound recording device could be used for. They are as follows:

  • Letter writing and dictation
  • Talking books for the blind
  • The teaching of elocution
  • Music recording
  • Recording of family voices
  • Music boxes and toys, such as dolls with voices
  • Talking clocks
  • Recording the speeches of great men
  • Educational records
  • An auxiliary to the telephone

Edison's phonograph was demonstrated at the White House and also at the French Academy of Sciences by DuMoncel, a physicist. While he was demonstrating the phonograph at the Academy, an attending physician, 82-year-old Jean Bouilland, grabbed DuMoncel by the throat and accused him of ventriloquism!

Edison's early invention later led to the more modern record turntable and the technology that later led to the creation of the compact disc. If it had not been for Edison's phonograph, much of the world's music would be lost to us today.

Incandescent Light (1879)

One day Edison saw the use of carbon-arc lighting that had been developed by William Wallace. Wallace's lamps had a 500 candlepower glow. Edison thought that this was a good idea but realised that it was totally impractical for home lighting since the lights were glaringly bright and burned out after a couple of hours. Edison knew that incandescent lighting was the way to go but that they were not yet efficiently developed. So off he set to develop an economic and practical incandescent bulb for home lighting. When Edison first set to work, he claimed that he would have electric lighting ready in six weeks; however, it took a lot longer.

Of course, even the most concentrated thinking cannot solve every new problem that the brain can conceive. It usually takes me (Edison) from five to seven years to perfect a thing. Some things I have been working on for 25 years - and some of them are still unsolved. My average would be about seven years. The incandescent light was the hardest one of all; it took many years not only of concentrated thought but also of worldwide research.

Edison tried many different filaments in over 4700 experiments. He knew he needed one that was very thin that wouldn't melt very easily. The ones he worked with the most were carbon and platinum. He thought of using tungsten (which is what is used in today's bulbs) but he didn't have tools delicate enough to handle it. Bamboo filaments were tested but they got very hot without getting very bright due to the fact that at operating temperatures more energy was radiated through infrared light than visible light. Edison had many successes with platinum but because of its expense it was impractical. Edison went back to experimenting with carbon since it had a high melting point and good conductivity. Edison had excessive newspaper coverage of this experiment for the whole duration of the project. When at last a long, bright burning bulb was created, there was great celebration. At the turn of the century, electricity was hailed as the new panacea.

Power Stations (1882)

Edison knew that if electric lighting was to become popular, he would have to create a system for producing and distributing electricity. The Pearl Street power station had Edison-designed generators driven by steam engines; the power was distributed over copper bars. The station supplied enough electricity to light 1200 bulbs and it serviced an area of about one square mile. On opening day it had 52 customers. Less than four years after Edison's first lightbulb his station was providing power for over 10,000 lamps for 400 customers.

Edison's major publicity for his power station as well as his incandescent lightbulb was mostly acquired by his intense competition with the gas lighting companies which were more popular at the time. Even when the idea of electricity caught on, he still had major rivals because his service was Direct Current. Edison hated Alternating Current; he claimed it was more dangerous than DC and lobbied for AC's use in the first electric chair electrocution in an attempt to undermine his competition.

Even though Edison's DC system eventually failed, it was important in conditioning people to the idea of lighting by electricity and the concept of a central power station supplying to many factories and homes.

The Kinetoscope (1888)

Edison wanted to create an invention that would do for the eye what the phonograph had done for the ear, that is, recording visual images. The main way he went about this was by using a celluloid film that had been invented earlier by a photographer by the name of George Eastman. This film was extremely thin and flexible and made it easy for Edison to run pictures through a wheel with sprockets so that the speed at which the pictures moved could be controlled. Edison's finished product was like a peep box where the viewer looked inside the machine when the movie was displayed. Although Edison created the first mobile movie studio, his attempt to control the movie industry failed. Edison's invention was the first big step in the right direction for movie making.

Cement Manufacture (1900)

After Edison had spent over 20 years trying to perfect his failing iron extraction process, he realised that he could use a similar process for cement manufacture. He was one of the first to mass produce cement, introducing a bunch of new ideas for the use of cement as well.

One of these ideas was to build complete houses from pre-formed pieces of concrete - including staircases, kitchen sinks and bath tubs. The houses were sold at a mere $600 (initial plans called for $300 each) but it turned out that people wouldn't want to be bound to the same floor plan as 100s of their neighbours. Furthermore, the insulation was bad and costs for heating were significant.

The new method of building dwellings of small cost, recently announced by Mr Thomas A Edison, opens tremendous additional possibilities for the use of concrete. Instead of the old box-like concrete structures with which we are all familiar, it will be possible to have attractive houses at a much lower cost than was possible in the first-mentioned type.

When asked in what particulars his idea was novel, Mr Edison said: 'There is nothing particularly novel about my plan: it amounts to the same thing as making a very complicated casting in iron, except that the medium is not fluid. Someone was bound to do it, and I thought that I might as well be the man to do it, that's all'.

So it was the introduction of a new industry that was the foundation of the construction of the Yankee Stadium which is still standing to this day.


Although very good at inventing, Edison wasn't overly successful at earning money from it. The 'Electric Light Company' which later on was renamed the 'Edison General Electric Company' earned millions of dollars, but Edison had failed to make sure he got his fair share out of the contracts. In 1892, the company fused with Thomson-Houston to become the 'General Electric Company', and Edison was out of the business.

Edison was never easily discouraged. He said that even if he had tried 500 or 1000 different variations on an experiment and not one had worked, then he had learned 500 or 1000 ways not to proceed with the experiment. Edison's hard work and perseverance paid off. There are many ideas and inventions that Edison never had time to work on during his life, but the ones that he did give to us have helped to advance our society in so many ways. On the day of Edison's death the population of the United States of America paid their respects to him by spending an entire minute without electricity. Edison was 'the last of the great all-round inventors'.

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