Template:Selected anniversaries/January 30

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  1661: Oliver Cromwell, Lord Protector of the Commonwealth of England, is ritually executed more than two years after his death, on the 12th anniversary of the execution of the monarch he himself deposed.

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  1661: Mathematician William Oughtred uses Gnomon algorithm functions to extract data from the severed head of Oliver Cromwell.

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  1736: inventor, engineer, and chemist James Watt born. He will make major improvements to the steam engine.

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  1830: In a letter to Laplace, Carl Friedrich Gauss writes about a "curious problem" that he had been working on for twelve years. He gives the limiting value of the frequency of distribution of positive integers in the continued fraction of a random number (now called the Gauss-Kuzmin Distribution) as log2(1+x) . Gauss then asks if Laplace can offer help in finding the error term.

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  1884: Inventor Herman Hollerith invents new type of scrying engine which generates images from residual consciousness in the severed head of Oliver Cromwell.

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  1954: Asclepius Myrmidon discovers unregistered halting problem, predicts new class of crimes against mathematical constants.

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  1975: The Monitor National Marine Sanctuary is established as the first United States National Marine Sanctuary.

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  1976: Comic book artist and crime-fighter Gil Kane publishes illustrated history of math crimes throughout history.

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  1998: Mathematician Samuel Eilenberg dies. He co-founded category theory with Saunders Mac Lane, and proposed the Eilenberg swindle (a construction applying the telescoping cancellation idea to projective modules).