Thomas Alva Edison (1847-1931) The man called "The Wizard of Menlo Park" was probably the world's greatest inventor. He invented many wonderful things. His name was Thomas Edison.
Edison's most famous invention was the incandescent electric lamp. In lamps of the kinds used before the days of electricity, something has to burn to make light. Kerosene is burned in a kerosene lamp, and gas is burned in a gas lamp. A candle gives off light when the wax in it burns. In an incandescent lamp something is heated white hot so that it glows. It does not burn up—at least, not for a long time.
Around the year 1879 many men were trying to make a good incandescent lamp. Three things were necessary. One was a way to heat the material until it glowed. Electricity does this easily when the material is in the form of a fine thread, called a filament. Another was a way to keep air away so that the filament would not burn. Edison solved this problem by sealing the filament in a glass bulb from which he pumped out the air. The third was Edison's biggest problem—a kind of filament which would glow white hot for a long time.
By the time Edison began working on his incandescent lamp, he was already a successful inventor with a staff of assistants. He sent some of his men far and wide to bring back material for filaments to his laboratory in Menlo Park, N. J.
Of the thousands of different filaments he tested, those made of carbon were found to be best. Carbon filaments were made by charring wood fibers, and some wood fibers worked better than others. Another long search was made. Finally a certain kind of bamboo fiber was found that seemed good. On October 21, 1879, Edison's first lamp made with a charred bamboo filament was ready to be tested.
The lamp was switched on. It glowed with a beautiful soft light. Breathlessly Edison and his helpers watched to see how long it would glow. Hour after hour they watched. No one wanted to sleep. They watched for two whole days and nights, and the lamp still glowed on. It was a success.
Since then incandescent lamps have been greatly improved. After Edison showed that such lamps could be made, many people became interested in trying to make better ones.
Edison was born in Milan, Ohio. He did not like school, but he enjoyed being taught at home by his mother. He also liked to learn things by himself by reading and experimenting. He had a laboratory in the basement of his home.
Edison started to earn money when he was very young. He wanted to buy for himself what he needed for his experiments.
Before he was 15 he published a newspaper which he called the Weekly Herald. His printing office was set up in the baggage car of a train on which he worked.
One day Edison saved the life of a little boy. The boy's father rewarded Edison by teaching him how to be a telegraph operator. As a telegraph operator Edison found ways to improve the methods of sending messages by telegraph.
Edison's inventions number well over 1,000. Important among them, in addition to the incandescent lamp, are motion pictures, the phonograph, the multiplex telegraph, the carbon telephone transmitter, and the microphone. All of us owe a great deal to this famous inventor.
