Всё сделанное в учебнике (переведены тексты и сделаны упражнения) (4B)Посмотреть архив целиком
Benjamin Franklin, an American who is famous for his interesting and useful inventions, published his ideas about electricity in 1752. Scientists in many countries became interested in this wonderful from of energy. They wanted to find the answer to a very important question: could the electricity be used to develop a fast, efficient system of long-distance communication? Experiments proved that electricity could travel instantly over a very long piece of wire. But a note that was written on a piece of paper couldn’t be put into a wire. How could electricity be used to send a message? A Danish scientist discovered that electricity could move a needle from left to right and that the needle could be pointed at letters on piece of paper. Then a German government worker made up a code system that could be used with an electric needle. In 1837 two English scientists sent a message by electric telegraph for a distance of more than 1.6 kilometers.
Samuel Morse, an American portrait painter, was experimenting with an electric telegraph too. At first he connected a pencil to an electric wire. When the electricity came through the wire the pencil made wavy lines. Then Morse invented a code that used dots and dashes for the letters of the alphabet. Finally, he discovered that telegraph messages did not have to be written, they could be sent in sound.
On May 24,1844, the first long-distance message was sent by telegraph for 64 kilometers.
Telegraph companies were formed in many cities. By 1861 telegraph wires stretched from the Atlantic to the Pacific. In Europe too, Samuel Morse’s system became popular.
But telegraph wires couldn’t be hung over an ocean. Messages to and from Europe had to be sent by ship-a journey of two or three weeks. A new method was needed.
The Atlantic Telegraph Company which was organized in 1856, wanted to try to lay a cable on the floor of the Atlantic Ocean.
The 4,000-kilometer cable broke three times. Each time a new cable had to be made. Finally, on July 27, 1866, the first transatlantic message was sent from Newfoundland to Ireland.
Later cables were laid to Central and South America. After 1900 transpacific cables were laid to Asia and Australia. At last and business information could be sent instantly to almost every country in the world.