29.8 MB (1.5 MB compressed)
3688 x 2824 pixels
31.2 x 23.9 cm ⏐ 12.3 x 9.4 in (300dpi)
FRANCOISE SAUZE / SCIENCE PHOTO LIBRARY FRANCOISE SAUZE / SCIENCE PHOTO LIBRARY
Bakelite telephones. Three early telephones with bakelite casing. The telephone was invented by Alexander Graham Bell in 1876 while he was experimenting with improvements to the telegraph. Bakelite, the first commercially successful plastic, was discovered in the 1920's by the Belgian-born chemist Leo Baekeland whilst he was doing research on synthetic varnishes in the U.S. It is a thermosetting plastic (it does not melt once it has been heated and set) and a good insulator. It was therefore the ideal material for casings for electrical devices such as telephones and radios.
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