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 an electric circuit and a magnet to make an 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. His assistant, Thomas Watson complied, and to his surprise, Bell heard the corresponding reed at his end of the line vibrate and sound the same - without any electric current to 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, 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 7, 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 was not made until March 10, 1876 when Bell spoke into his device, "Mr. Watson, come here, I want to see you." and Watson answered back and came into the room to see Bell. The first long distance telephone call was made on August 10, 1876 by Bell from the family home in Brantford, Ontario to his assistant in Paris, Ontario, some 16 km (10 mi.) away.
On March 7, 1876, the U.S. Patent Office gave him patent #174465 for the "telephone".
Bell is also credited with the invention of an improved metal detector in 1881 that made sounds when it was near metal. The device was quickly put together in an attempt to find the bullet in the body of U.S. President James Garfield. The metal detector worked, but did not 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.
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.
As a teacher of the deaf, Bell did not want deaf people to teach in schools for the deaf. He was also against the use of sign language. These things mean that he is not appreciated by some deaf people in the present day.
Heinrich Rudolf Hertz
Heinrich Rudolf Hertz (22 February 1857 – 1 January 1894) was a German physicist. In 1888 he discovered the radio waves previously predicted by Maxwell's equations. He also proved that light is a kind of electromagnetic waves. The unit for frequency is named after him.
Hertz was born in Hamburg in 1857. He studied engineering in Frankfurt and later at the University of Munich. He completed his PhD at the University of Berlin. He taught and continued research at the University of Bonn and University of Kiel.
He died from blood poisoning in 1894.
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Year 1687 was a common year that started on a Wednesday when using the Gregorian calendar.
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Deep house
Deep house is a type of house music. It has influences from disco music and jazz music. The BPM of deep house is usually 100 - 128.
Cytokine
Cytokines are a group of signalling molecules made by cells. They help to control the immune system and fight disease. They are similar to hormones and, as we learn more about each, distinctions between the two are fading.
Cytokines carry signals locally between cells, and these signals have an effect on other cells. They are made of proteins, peptides, or glycoproteins. The cytokines are a large family of polypeptide regulators that are produced throughout the body by many groups of cells.
Some well-known cytokines include interferon, prostaglandin and interleukins. Cytokines can be detected using the ELISA and ELISPOT techniques.
Cytokines work by signal transduction. Each cytokine has a matching cell-surface receptor. Then cascades of signals inside the cell changes cell functions. This may include the regulation of several genes, the production of other cytokines, or an increase in surface receptors for other molecules.
Bristol
Bristol is a city and ceremonial county in England. It is home to nearly 430,000 people. The River Avon runs through it to the Severn estuary.
It is between the counties of Gloucestershire and Somerset. In 1373, King Edward III ordered that it should be a county itself forever. However, it lost county status in 1974, the year after its 600-year celebrations. It became the largest district within the new Avon county. Avon was never popular and was abolished in 1996, when county status returned to Bristol, which became a unitary council.
The Bristol name means "the place where the bridge is" in Old English. It has been a port for 800 years. Now, ships are too big to reach it. It has a new seaport at Avonmouth.
It has many historic churches and other buildings. The Clifton Suspension Bridge crosses high above the river. The University of Bristol is also in Clifton.
Bristol was a centre for the slave trade. During the 2020 George Floyd protests, a crowd pushed down the statue of 17th century slave trader Edward Colston and threw it in the harbour.
Bristol was badly damaged during World War II. It now has many new factories and offices. The Concorde supersonic airliner was made here.
It is also the birthplace of the music genre trip hop., with 3 trip hop bands originating there: Massive Attack, Portishead (named after a North Somerset town) and Tricky.
Some of the most notable people who are currently living, or who are from the city include:
List of cities and towns in England
This is a link page for towns and cities in England. In England, Wales and Northern Ireland, a town is any settlement which has received a charter of incorporation, more commonly known as a town charter, approved by the monarch. Cities are indicated in bold.
Abingdon, Accrington, Acton, Adlington, Alcester, Aldeburgh, Aldershot, Aldridge, Alford, Alfreton, Alnwick, Alsager, Alston, Alton, Altrincham, Amble, Amersham, Amesbury, Ampthill, Andover, Appleby-in-Westmorland, Arundel, Ashbourne, Ashburton, Ashby-de-la-Zouch, Ashford, Ashington, Ashton-in-Makerfield, Ashton-under-Lyne, Askern, Aspatria, Atherstone, Attleborough, Axbridge, Axminster, Aylesbury, Aylsham.