On April 17, 1761, English mathematician and Presbyterian minister Thomas Bayes passed away. He is best known as name giver of the Bayes' theorem, of which he had developed a special case. T expresses (in the Bayesian interpretation) how a subjective degree of belief should rationally change to account for evidence, and finds application in in fields including science, engineering, economics (particularly microeconomics), game theory, medicine and law.
On April 4, 1617, Scottish mathematician, physicist, astronomer and astrologer John Napier of Merchiston, the 8th Laird of Merchistoun passed away. John Napier is best known as the discoverer of logarithms. He was also the inventor of the so-called "Napier's bones", a kind of abacus for calculation of products and quotients of numbers. Napier also made common the use of the decimal point in arithmetic and mathematics.