5 Chapter 4 His Invention Factory

Chapter 4 His Invention Factory In the mid 1800s, a man in France and a man in Massachusetts both came up with ways to record sound—but as a pattern on paper much the way the dots and dashes of Morse code look on paper. Nobody had figured out how to record sounds and play them back so they could be heard again. That's what Tom wanted to do. He had an idea. But he didn't know if it would work. He had drawn some rough sketches. But that was all.

For eight months Tom and his team kept working on his idea for a phonograph. They were working on other inventions too. They were not in a big hurry. But then an article appeared in an important magazine, Scientific American. It said that Thomas Edison had invented an amazing machine. It played the human voice. "A wonderful

invention," they announced with great fanfare. Tom knew that everyone would be asking to hear his amazing phonograph. Now Tom was in a big hurry. Had someone at Menlo Park told a reporter about what Tom was working on? Maybe. Tom didn't mind. Maybe he even knew who had told the magazine about the phonograph. He liked publicity. But now he had to make his phonograph. And soon. It was November 1877. Tom sat down and did another rough sketch. He gave it to his best machinist. Anyone else might look at his drawing and wonder how to follow it. But this machinist was used to Tom's sketches. A week later he came back with a model.

The model had a long screw with a handle at one end. The screw ran through the middle of a metal cylinder wrapped in tinfoil. On either side of the cylinder was a metal disk with a pin and a short hollow tube.

Tom leaned toward the machine, turned the handle, and spoke into one of the tubes as the cylinder moved along the screw. "Mary had a little lamb. Its fleece was white as snow. And everywhere that Mary went, the lamb was sure to go." The sound of Tom's voice made the metal disk with the pin vibrate and scratch a sound pattern on the tinfoil. When he stopped speaking, Tom pulled the pin away from the cylinder. He turned the handle in the opposite direction and moved the cylinder back to where it had been. He put the pin on the other side against the cylinder.

HOW THE PHONOGRAPH WORKS