Alexander bell—the inventor of the telephone

Alexander Bell never planned to be an inventor. He wanted to be a musician or a teacher

of deaf people. In 1863, when Alexander was only 16, he became a teacher in a boys' school in Scotland. But the wish to teach deaf people made him to read books about sound and started to work on some of his own experiments. Reading scientific literature was not easy for him, but he worked hard and learned a lot about the laws of sound. He became interested in the telegraph, and he tried to find a way to send musical sounds through the wires. These experiments were not very successful.

At the age of twenty-five Bell became interested in finding a way to send the human voice

through an electric wire. He found an assistant, Tom Watson, who knew a lot about building electric machines. They worked together to build a machine that people could use to talk to one another over long distances.

Two years later when two young men were, working on a new transmitter, Alexander spilled some acid on himself. Tom Watson, who was alone in another room, heard a voice. The voice was coming through a wire to a receiver on the table. The voice was Alexander Bell's! It was saying, 'Come here, Mr. Watson. I want you!' Tom and Alexander realized that their talking machine worked'.

The first permanent telephone line was built in Germany in 1847. And in 1878, the first telephone exchange-was established in New Jersey. By 1915, a coast-to-coast telephone line was opened in the United States—5,440 km from New York to San Francisco.

Text 4

THE INVENTOR OF THE RADIO

A.S. Popov, the great Russian inventor, was born in 1858. By the time he graduated from the Petersburg University (1883) he had already had a broad knowledge of electrical theory as well as a wide experience in that field.

Popov was one of the first to pay attention to the works of Hertz who proved by experiments the existence of electromagnetic waves. After many experiments Popov carried out together with his assistant Rybkin, the device they constructed started receiving electromagnetic waves at a distance. By means of his receiver Popov could detect the waves at a distance of several meters and then several kilometers. While making experiments the scientist discovered that when a wire was connected to the receiver, the range of operation increased. After that he connected his first receiver to the first antenna.

On April 25, 1895, A. Popov demonstrated his device at the Russian Physico-Chemical Society. Popov expressed hope that the device, after being perfected, would make it possible to transmit signals at a distance by means of rapid electrical oscillations. In summer 1895, Popov's invention was successfully tested and in the same year he attached to the device an apparatus used for recording telegrams over the wire telegraph. In the following year this receiver was used at an electric power station in Nizhny Novgorod.

In 1897, Popov successfully carried out his experiments at sea, having succeeded in effecting radio communication between the shore and the sea at a distance of 3 km.

In those days the future wireless communication between the continents was being founded. The year of 1898 saw a new important invention made by Popov together with his assistants Rybkin and Troitsky the reception of signals by means of a receiver. Successful experiments having been completed, serious practical testing was started. In those days Popov's radio telegraph helped to save the ship 'General-Admiral Apraksin'.

Popov's work became known in many foreign countries. He was offered great profits from commercial use of his invention in case he agreed to leave Russia. But, being a true patriot of his fatherland; the inventor refused to leave Russia. 'I am a Russian and I must give my knowledge, my work and all my achievements to my native land' such were his words.

Though many prominent people in Russia and the leading scientists realized the importance of Popov's inventions for the future of the mankind, the tsarist government did nothing to provide training specialists for the new branch of science. Neither was home production of devices for wireless telegraphy organized in Russia. Instead it was handed over to the foreign companies. On the 31^st of December, 1905, the great inventor died at the age of 47.

By the beginning of the war, in 1914, the results of Popov's work were concentrated in foreign hands.

Text 5 _{CHARLES BABBAGE}

Charles Babbage was born in1791 in Teignmouth, Devonshire UK and died in 1871. He

founded the British Association's Statistical Society and the Royal Astronomical Society. He took

no part in 'the divorce between academic science and engineering practice'. He loved practical

science, and was among the first to apply higher mathematics to certain commercial and