April 8

Are You Sure ... (April 8)

• ... that physician and archaeologist Michele Mercati (8 April 1541 – 25 June 1593) was among the first scholars to recognize prehistoric stone tools as human-made rather than natural or mythologically created thunderstones?

• ... that physicist Heike Kamerlingh Onnes (21 September 1853 – 21 February 1926) discovered superconductivity in 1911, writing in his notebook on April 8: Kwik nagenoeg nul ("Mercury[’s resistance] practically zero [at 3 K].").

• ... that inventor, astronomer, mathematician, clockmaker, and surveyor David Rittenhouse (8 April 1732 – 26 June 1796) was the first Director of the United States Mint, and that Rittenhouse personally struck the new nation's first coins by hand?

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Screenshot: Are You Sure (April 8, 2021)

On This Day in History and Fiction

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  1541: Physician and archaeologist Michele Mercati born. Mercati will be one of the first scholars to recognize prehistoric stone tools as human-made rather than natural or mythologically created thunderstones.

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  1732: Inventor, astronomer, mathematician, clockmaker, and surveyor David Rittenhouse born. Rittenhouse will become the first Director of the United States Mint, hand-striking the new nation's first coins.

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  1803: Mathematician Louis François Antoine Arbogast dies. Arbogast was the first writer to separate the symbols of operation from those of quantity. He wrote on series and the derivatives known by his name.

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  1903: Mathematician Marshall Harvey Stone born. Stone will contribute to real analysis, functional analysis, topology, and the study of Boolean algebra structures.

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  1911: Physicist Heike Kamerlingh Onnes, discoverer of superconductivity, makes a terse entry in his notebook: Kwik nagenoeg nul ("Mercury[’s resistance] practically zero [at 3 K].").