Day in Engineering History Archive - October 20

Day in Engineering History October 20 Archive - RF CafeOctober 20

Please click here for the RF Cafe homepage1818: The U.S. and Great Britain established the boundary between the U.S. and Canada to be the 49th parallel. 1891: English Nobel Prize winner James Chadwick, discoverer of the neutron, was born. 1944: General Douglas MacArthur stepped ashore at Leyte in the Philippines, 2 1/2 years after he had said, ''I shall return.'' 1956: American aircraft designer Lawrence Bell, founder of Bell Aircraft (maker of the Bell X-1 the first broke the sound barrier), died. 1960: The length of the meter was redefined to be equal to 1,650,763.73 wavelengths in vacuum of the radiation corresponding to the transition between the 2p10 and 5d5 quantum levels of the krypton-86 atom. 1960: The first fully mechanized post office opened in Providence, RI. 1972: American astronomer Harlow Shapley, who discovered the sun's position in the Milky Way galaxy, died. 1983: IBM-PC DOS Version 2.1 was released. 1984: English physicist Paul Dirac, who shared a Nobel Prize with Erwin Schrödinger, and after whom the Dirac delta function is named, died.

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Note: These historical tidbits have been collected from various sources, mostly on the Internet. As detailed in this article, there is a lot of wrong information that is repeated hundreds of times because most websites do not validate with authoritative sources. On RF Cafe, events with hyperlinks have been verified. Many years ago, I began commemorating the birthdays of notable people and events with special RF Cafe logos. Where available, I like to use images from postage stamps from the country where the person or event occurred. Images used in the logos are often from open source websites like Wikipedia, and are specifically credited with a hyperlink back to the source where possible. Fair Use laws permit small samples of copyrighted content.