Shelford Bidwell facts for kids

Shelford Bidwell (FRS) was an English physicist and inventor. He was born on March 6, 1848, and passed away on December 18, 1909. He is best known for his work on "telephotography," which was an early version of today's fax machine.

Early Life and Interests

Shelford Bidwell was born in Thetford, Norfolk. He was the oldest son of Shelford Clarke Bidwell, who was a brewer. He went to Caius College, Cambridge University. After college, he became a lawyer. He worked as a barrister for several years. Later, he became very interested in electronics and science.

In 1874, he married Anna Wilhelmina Evelyn. He lived with his family in London and later in Weybridge, Surrey. He passed away in Weybridge and was buried in Walton-on-Thames.

Amazing Inventions and Discoveries

In the late 1870s, Shelford Bidwell did many experiments. He worked with special devices called selenium photocells. These cells can turn light into an electrical signal.

The Photophone

In one experiment, he built a device similar to the "photophone" made by Alexander Graham Bell. This device used sound to make a mirror vibrate. The light reflecting off the mirror would change. A selenium photocell then detected these changes. This showed that voices could be sent using light beams. The photocell changed the light back into an electrical signal.

Early Fax Machine Ideas

In another experiment, Bidwell put a selenium photocell inside a spinning cylinder. A small hole in the cylinder let the photocell "scan" an image. This image was on a bright glass slide. Another spinning cylinder was covered with paper. This paper had a special chemical on it. The electrical signal from the photocell went to a wire. This wire darkened the paper when electricity flowed through it.

Bidwell's device was very clever. It was one of the first to use a photocell to scan an image. He wrote about his findings in an article called "Tele-Photography." This article was in the Nature magazine on February 10, 1881. His invention can still be seen at the London Science Museum. In 1886, he became a Fellow of the Royal Society. He also led the Physical Society from 1897 to 1899.

Thinking About Television

In 1908, Bidwell wrote another article in Nature. It was called "Telegraphic Photography and Electric Vision." In this article, he talked about the challenges of creating "distant electric vision," which we now call television.

He explained that it was hard to make the sending and receiving parts work together perfectly. But an even bigger problem was sending huge amounts of information very quickly. To create a smooth, moving picture, he thought each image would need thousands of "elements" (like today's pixels). Also, at least 10 images would need to be sent every second.

He suggested that this high speed might need a separate electrical path for each line or even each point in the image. This would make the device very big, complex, and expensive. His article showed the big problems scientists faced when trying to invent television. It also showed some ideas they had to solve them. Interestingly, his article led to a response from Alan Archibald Campbell-Swinton. Campbell-Swinton suggested using cathode ray tubes instead of mechanical parts. This idea was very important for the future of television.

Bidwell's Ghost

Shelford Bidwell also has a visual effect named after him. It's called "Bidwell's ghost." This is a visual phenomenon related to after-images. You might see it when alternating flashing lights are used.