Lesson 35. The theme: Inventions

Lesson 35.

1. The theme: Inventions

2. Speaking: Current events.

From the History of Edison’s Inventions

Almost all of Edison’s inventions had practical use. As you already know, in 1869 he took out patent for automatic telegraph system and the electric pen. His invention of the carbon microphone marked a new age in the telephony and helped in bringing the telephone into everyday use.

You are to know that a microphone is a device for delivering electric signals corresponding to the variations in the air pressure which sound waves produce. The following diagram shows Edison’s microphone principle.

As you can see from the diagram, sound waves fall on the diaphragm of the device. The changing pressure of the waves produces the corresponding variations in the electric current. This way the microphone transforms the sound signals into the electric ones. In 1877 Thomas Edison made his new invention. This time it was a speaking machine which he called a phonograph. For the first time in history a mechanical device recorded the voice of man. All America talked of this invention. Thousands of people came by trains to see how the phonograph spoke. Even the President of the United States himself invited Edison to the White House to demonstrate the new machine.

Ten years later Edison developed a number of speaking machines which were much better than his first models. They were much smaller and had motors and disks instead of cylinders. But not in all European countries, people and even scientists understood the meaning of Edison’s great invention. Even in England the public refused to use it for a long time.

In France at the demonstration of the “speaking machine” before the members of Academy of Sciences, one of the members of the Academy said, “It is a shame to show such things to people to deceive them because every man knows that a metal thing can not speak”. In Russia at the public demonstration of the first machine, a member of the government protested against it and arrested for three months the man who demonstrated the “speaking machine”. Only one hundred years separates us from the time when Edison invented his first “speaking machine” but now we cannot think of our everyday life without recording and speaking apparatuses. They are quite necessary for our laboratories as well as for our classrooms. Today the recording and speaking machines not only speak but also help teach us languages as well as other subjects.