Willebrord Snellius

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Willebrord Snellius
University of Leiden
Academic advisors	Ludolph van Ceulen Rudolph Snellius
Notable students	Jacobus Golius

Willebrord Snellius^[1][2] (born Willebrord Snel van Royen)^[3] (13 June 1580^[4] – 30 October 1626) was a Dutch astronomer and mathematician, commonly known as Snell. His name is usually associated with the law of refraction of light known as Snell's law.^[5]

The

.

Biography

Willebrord Snellius was born in

Snellius' triangulation

It has been suggested that this section be Snellius' triangulation. (Discuss ) (May 2021)

In 1615, Snellius, after the work of

of 38,653 km. The actual circumference is 40,075 kilometers, so Snellius underestimated the circumference of the earth by 3.5%.

Snellius came to his result by calculating the distances between a number of high points in the plain west and southwest of the Netherlands using triangulation. In order to carry out these measurements accurately Snellius had a large quadrant built, with which he could accurately measure angles in tenths of degrees. This quadrant can still be seen in the Museum Boerhaave in Leiden. In a network of fourteen cities a total of 53 triangulation measurements were made. In his calculations Snellius made use of a solution for what is now called the Snellius–Pothenot problem.

By necessity Snellius's high points were nearly all

The actual distance between the two church spires in Alkmaar and Breda, two places nearly on the same meridian,^[11] is 116.1 kilometers.^[12] The difference in latitude between Alkmaar (52° 37' 57" N) and Breda (51° 35' 20" N) is 1.0436 degree. Assuming Snellius corrected for this he must have calculated a distance of 107.37 * 1.0436 = 112.05 kilometers between the Sint-Laurenskerk in Alkmaar and the Grote Kerk in Breda.

Mathematics and physics

Snellius was also a distinguished mathematician, producing a new method for calculating

Other works

In addition to the Eratosthenes Batavus, he published Cyclometricus, de circuli dimensione (1621), and Tiphys Batavus (1624). He also edited Coeli et siderum in eo errantium observationes Hassiacae (1618), containing the astronomical observations of Landgrave

Death

Snellius died in Leiden in October 1626, at the age of 46 from an illness diagnosed as colic.^[14] His grave can be seen in the Pieterskerk, Leiden.

Honours

Snellius Glacier in Antarctica is named after Willebrord Snellius.

Works

• Eratosthenes Batavus (in Latin). Lugduni Batavorum: Joost van Colster, Joris Abrahamsz van der Marsce. 1617.
• Coeli et siderum in eo errantium observationes Hassicae (in Latin). Lugduni Batauorum: Joost van Colster. 1618.
• Cyclometricus (in Latin). Lugduni Batavorum: Matthijs Elzevier, Bonaventura Elzevier. 1621.
• Doctrinae triangulorum canonicae libri quatuor (in Latin). Lugduni Batavorum: Joannes Maire. 1627.

Notes

See also

• Snell–Huygens refinement

References

• Willebrord Snellius (1580-1626): a humanist reshaping the mathematical sciences, thesis of Liesbeth de Wreede, Dissertation Utrecht 2007
• N. Haasbroek: Gemma Frisius, Tycho Brahe and Snellius and their triangulations. Delft 1968.
• ISBN 978-0-684-10114-9
  .
• "Snellius (Willebrord)". Nieuw Nederlandsch Biografisch Woordenboek. Vol. VII.
• O'Connor, John J.; Robertson, Edmund F., "Willebrord van Royen Snell", MacTutor History of Mathematics Archive, University of St Andrews
•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Snell, Willebrord". Encyclopædia Britannica. Vol. 25 (11th ed.). Cambridge University Press. p. 293.
• Klaus Hentschel: Das Brechungsgesetz in der Fassung von Snellius. Rekonstruktion seines Entdeckungspfades und eine Übersetzung seines lateinischen Manuskriptes sowie ergänzender Dokumente. Archive for History of Exact Sciences 55,4 (2001), doi:10.1007/s004070000026.

External links

Wikimedia Commons has media related to Willebrord Snellius.

• Willebrord Snellius at the Mathematics Genealogy Project
• Works by Willebrord Snellius at Open Library (in Latin)
• Works by or about Willebrord Snellius at Internet Archive (in Latin)