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Day in Engineering History Archive - April 21

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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.
Please submit significant historical events and dates for inclusion in these lists. I will be glad to include your name and birthday. Please do not submit your death date ;-) A couple 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.

April 21

Happy Birthday to Jean-Baptiste Biot (Biot-Savart Law)!  Please click here to visit RF Cafe.

1774: Jean-Baptiste Biot, co-developer of the Biot-Savart law of electromagnetic induction, was born. 1836: General Sam Houston defeated Santa Anna at the Battle of San Jacinto, which decided the independence of Texas. 1856: The Mississippi River was crossed by a rail train for the first time. 1910: Samuel Clemens (aka Mark Twain) died, the same year as an appearance of Halley's Comet and, amazingly, the comet's previous appearance came during November 1835, the year of Clemens' birth (throughout his life, Clemens said that he would "go out with the comet"). 1918: German fighter ace Manfred von Richtofen, "The Red Baron," was shot down and killed during World War I. 1948: The first Polaroid camera was sold. 1972: Apollo 16 astronauts John Young and Charles Duke explored the surface of the moon in their LEM.


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