பேச்சு:அலெக்ஸாண்டர் கிரஹாம் பெல்

கட்டற்ற கலைக்களஞ்சியமான விக்கிபீடியாவில் இருந்து.

பொருளடக்கம்

[தொகு] வாழ்க்கைக் குறிப்பு

Bell was born in Edinburgh, Scotland. His family was known for teaching elocution, or clear speaking. His grandfather taught in London, his uncle in Dublin, and his father, Mr. Alexander Melville Bell, in Edinburgh. His father wrote often on the subject and is most known for his treatise on Visible Speech, which appeared in Edinburgh in 1868. In this, he explains a method of teaching people who are deaf and mute. It shows how these people can learn to speak words by using their eyes to read what other people are saying by watching their lips.

Alexander Graham Bell went to school at the Royal High School of Edinburgh. He graduated at the age of thirteen. At the age of sixteen, he got a job as a student and teacher of elocution and music in Weston House Academy, at Elgin, Moray|Elgin in Morayshire. He spent the next year at the University of Edinburgh. From 1866 to 1867, he was an teacher at Somersetshire College at Bath, England. While still in Scotland, he became more interested in the science of sound - acoustics. He hoped to be able to help his deaf mother.

Later, while he was still a young man, he moved with his family to Canada where they settled at Brantford, Ontario. Bell turned his attention to communication machines. He designed a piano which could transmit its music to a distance by using electricity. In 1873, he went with his father to Montreal, Quebec in Canada, where he took a job in teaching the system of visible speech. His father was invited to teach the system at a large school for mutes in Boston, Massachusetts|Boston, but he instead he gave the offer to his son. Alexander G. Bell soon became famous in the United States for his success in this important work. He published many writings on the subject in Washington, D.C., and it is mainly through this work that thousands of deaf mutes in United States|America are now able to speak, even though they can't hear.

Bell and others formed the Bell Telephone Company in July, 1877. In 1879, it joined with the New England Telephone Company forming the National Bell Telephone Company. In 1880, they formed the American Bell Telephone Company, and in 1885, AT&T|American Telephone and Telegraph Company (AT&T), which remains active today. Along with Thomas Edison, Bell formed the Oriental Telephone Company on January 25, 1881.

Bell married Mabel Hubbard on July 11, 1877. He died in Baddeck, Nova Scotia|Baddeck, Nova Scotia in 1922.

[தொகு] கண்டுபிடிப்புகள்

Bell's genius is seen in part by the eighteen patents granted in his name alone and the twelve that he shared with others. These included fourteen for the telephone and telegraph, four for the photophone, one for the phonograph, five for aerial vehicles, four for hydroairplanes, and two for a selenium cell. In 1888, he was one of the original members of the National Geographic Society and became its second president.

He was the recipient of many honors.

  • The France|French government gave him the decoration of the (Legion of Honor).
  • They gave him the Volta prize of 50,000 francs.
  • The Royal Society of Arts in London awarded him the Albert medal in 1902.
  • The University of Würzburg, Bavaria, granted him the Degree of Ph.D.

[தொகு] தொலைபேசி

His past experience made him ready to work more with sound and electricity. He began his studies in 1874 with a musical telegraph, in which he used a electric circuit and a magnet to make a iron reed or tongue vibrate. One day, it was found that a reed failed to respond to the current. Mr. Bell desired his assistant, who was at the other end of the line, to pluck the reed, thinking it had stuck to the magnet. Mr. Watson complied, and to his surprise, Bell heard that the corresponding reed at his end of the line began to vibrate and sound the same not - without any electric current to make power it. A few experiments soon showed that his reed had been set in vibration by the changes in the magnetic field that the moving reed produced in the line. This discovery led him to stop using the electric battery current. His idea was that, since the circuit was never broken, all the complex vibrations of speech might be converted into currents, which in turn would reproduce the speech at a distance.

Bell, with his assistant Watson, devised a receiver, consisting of a stretched film or drum with a bit of magnetised iron attached to its middle, and free to vibrate in front of the pole of an electromagnet in circuit with the line. This apparatus was completed on June 2, 1875. On July 7th, he instructed his assistant to make a second receiver which could be used with the first, and a few days later they were tried together, at each end of the line, which ran from a room in the inventor's house at Boston to the cellar underneath. Bell, in the room, held one instrument in his hands, while Watson in the cellar listened at the other. The inventor spoke into his instrument, "Do you understand what I say?" and Mr. Watson rushed back into the upstairs and answered "Yes." The first successful two-way telephone call wasn't made until March 3, 1876 when Bell spoke into his device, "Mr. Watson, come here, I want to see you." and Watson answered back. The first long distance telephone call was made on August 10, 1876 by Bell from the family home in Brantford, Ontario to his assistant located in Paris, Ontario, some 16 kilometre|km (10 mile|mi.) away.

On March 7, 1876, the U.S. Patent Office gave him patent #174465 for the telephone.

[தொகு] Photophone

After that, Bell continued his experiments in communication, which led to the invention of the photophone – sending of sound on a beam of light. Bell worked with Charles Sumner Tainter. In his paper on the phonophone, Bell gave credit to A. C. Browne of London with the discovery in 1878. Bell and Tainter, however, were likely the first to perform a successful experiment. It was not an easy task, as they had to produce selenium cells with the desired properties themselves.

In one experiment in Washington, D.C., the sender and the receiver were placed on in different buildings some 830 Foot|ft. (about 250 metres) apart. The sender had a mirror directing sunlight onto the mouthpiece, where the light beam was chnged by a vibrating mirror. It was focused by a lens and sent at the receiver, which was a parabolic|curved mirror with the selenium cells in the focus and a telephone attached. With this setup, Bell and Tainter succeeded to communicate clearly.

The photophone was patented on December 18, 1880. However, since the light beam was not shielded in any way against external interference, the quality of communication was not always good, and it only worked within line-of-sight. It is still considered a precursor of the much later fiber optic technology, which is based on the same ideas, but remove these limits.

[தொகு] Metal detector

Bell is also credited with the invention of the metal detector in 1881. The device was quickly put together in an attempt to find the bullet in the body of President of the United States|U.S. President James Garfield. The metal detector worked, but didn't find the bullet because of the metal bedframe the President was lying on. Bell gave a full description of his experiments in a paper read before the "American Association for the Advancement of Science" in August, 1882.

[தொகு] Bel and decibel

The bel is a measure that was named after him. The bel is so large a unit of measure that the tenth of a bel, or "decibel" is what is commonly used. See acoustics for technical information.

[தொகு] Eugenics

Bell was an active supporter of the eugenics movement in the United States. He was the honorary president of the "Second International Congress of Eugenics" held at the American Museum of Natural History in New York in 1921. His work with organizations such as this helped to pass laws in many states meant to stop some people from having children; like the deaf, the crime|criminally insane, and the mentally defective. He didn't want deaf people to be allowed to teach in schools for the deaf. He also worked to pass laws that would not allow deaf people to marry others who were deaf. He was also against the use of sign language. These things mean that he is not liked by many deaf people today.