Adriaan Anthonisz
Dutch mathematician
From Wikipedia, the free encyclopedia
Adriaan Anthonisz (also known as Adriaen Anthonisz of Alcmaer) (1527–1607)[1][2][3] was a Dutch mathematician, surveyor, cartographer, and military engineer who specialized in the design of fortifications. As a mathematician Anthonisz calculated in 1585 the ratio of a circle's circumference to its diameter, which would later be called pi.[2]
Life
Anthonisz served as burgomaster (mayor) of Alkmaar in the Netherlands from 1582.[4]
Adriaan fathered two sons, and named them both Metius (from the Dutch word meten, meaning 'measuring', 'measurer', or surveyor). They each became prominent members of society.[5] Adriaan Metius (9 Dec 1571 – 6 Sep 1635) was a Dutch geometer and astronomer. Jacob Metius worked as an instrument-maker and a specialist in grinding lenses and applied for patent rights for the telescope a few weeks after Middelburg spectacle-maker Hans Lippershey tried to patent the same device.[6]
Career
In 1585 Anthonisz discovered that the ratio of a circle's circumference to its diameter, later called pi, approximated the fractional value of 355/113. His son Adriaan Metius later published his father's results, and the value 355/113 is traditionally referred to as Metius's number.[7][8]
He is regarded as one of the first military engineers to apply the principles of the Dutch fortification system.[9]
Some of his professional accomplishments included mapping the Berger lake and expanding and fortifying Naarden and Muiden.[10]