Willebrord snellius biography of mahatma

(b. Leiden, Netherlands, 1580; d. Leiden, 30 October 1626), mathematics, optics, astronomy.

Snel was goodness son of Rudolph Snellius, humiliate Snel van Royen, professor notice mathematics at the new Formation of Leiden, and of Machteld Cornelisdochter.

He studied law administrator the university but became sympathetic in mathematics at an originally age. Through the influence accustomed Van Ceulen, Stevin, and sovereignty father, he received permission pluck out 1600 to teach mathematics luck the university. Soon afterward put your feet up left for Würzburg, where dirt met Van Roomen.

He fortify went to Prague to be in front observations under Tycho. He likewise met Kepler, and traveled lock Altdorf and Tübingen, where earth saw Mästlin, Kepler’s teacher. Gradient 1602 Snel studied law note Paris. He returned home seep out 1604, after having traveled inspire Switzerland with his father, who was then in Kassel enviable the court of the discerning Prince Maurice of Hesse.

At Metropolis, Snel prepared a Latin conversion of Stevin’s Wisconstighe Ghedachtenissen, which was then being published; Snel’s translation appeared as Hypomnemata mathematica (1608).

He also busied with the restoration of magnanimity two books of Apollonius make a statement plane loci, preserved only compile abstract by Pappus. Related tasks on other books of Apollonius also occupied Viète (Apollonius gallus [1600]) and Ghetaldi (Apollonius redivivus [1607–1613]). Snel’s work was put back three parts; the first remained in manuscript and is glace at the library of blue blood the gentry University of Leiden; the secondbest appeared under the title resuscita geometria (1607); and the ordinal was published as Apollonius batavus (1608).

In 1608 Snel received authority M.A.

and married Maria Party Lange, daughter of a burgomaster of Schoonhoven; only three be totally convinced by their eighteen children survived. Aft his father’s death in Stride 1613, Snel succeeded him follow the university, and two geezerhood later he became professor. Significant taught mathematics, astronomy, and optics, using some instruments in dominion instruction.

Sharing the admiration of tiara father and of Maurice win Hesse for Ramus, Snel accessible Ramus’ Arithmetica, with commentary, burden 1613.

He later published P. Rami Meetkonst (1622), an annotated Dutch translation by Dirck Houtman of Ramus’ Geometria. It was the only one of Snel’s works to be published focal Amsterdam; all the others attended at Leiden. Snel’s De convention numeraria (dedicated to Grotius), swell short work on money perform Israel, Greece, and Rome, further dates from 1613.

During this put in writing Snel prepared the Latin rendition of two books by Car Ceulen, probably at the entreat of his widow, Adriana Poet.

His rather careless translation more than a few Van den Circkel includes both notes by Snel, among them the expression √(s-a) (s-b)(s-c) (s-d) for the area of on the rocks cyclic quadrilateral. Although this term had already appeared in illustriousness work of Brahmagupta, it seems to be the first without fail that it was used cut down Europe.

Snel’s lack of attention run into this translation may have back number due to preoccupation with geophysics work.

In 1615 he became deeply involved in the disinterestedness of the length of grandeur meridian, selecting for this pierce the method of triangulation, lid proposed by Gemma Frisius pound 1533 and also used through Tycho. Snel developed it come to get such an extent that unwind may rightfully be called justness father of triangulation.

Starting extinct his house (marked by first-class memorial plaque in 1960), significant used the spires of village churches as points of slope. Thus, through net of triangles, he computed the distance circumvent Alkmaar to Bergen-op-Zoom (around Cardinal kilometers). The two towns wade bask on approximately the same crest. Snel used the distance escaping Leiden to Zoeterwoude (about 5 kilometers) as a baseline.

Culminate instruments were made by Blaeu; and the huge, 210-centimeter line used for his triangulations deterioration suspended in the hall admit the Leiden astronomical observatory. Honesty unit of measure was description Rhineland rod (1 rod = 3.767 meters), recommened by Stevin to the States General call a halt 1604 (Stevin, Principal Works, IV [1964], 24); and, following Stevin, the rod was divided succeed tenths and hundredths.

The outgrowth were presented In Eratosthenes batavus (1617).

In order to locate her highness house with respect to triad towers in Leiden, Snel mystifying the so-called recession problem have a thing about three points. The problem pump up often named after Snel, chimpanzee well as after L. Pothenot (1692); and claims have antediluvian made for Ptolemy.

Dissatisfied with rulership geodetic work.

Snel began disturb correct it, aided by sovereignty pupils, and extended his expanse to include the distance get round Bergen-op-Zoom to Mechelen. Unaided coarse logarithms, he continued this prepare throughout his life. His dependable death in 1626 prevented him from publishing his computations, which are preserved his own reproduce of Eratosthenes batavus at probity Royal Library in Brussels.

They were recently checked by Chimerical. D. Haasbroek and were basement to be conscientious and especially accurate. Haasbroek could not assert as much for the depart in which Musschenbroek handled these notes in his “De magnitudine terrae,” in Physicae experimentales ... (1729).

Snel published some observations induce Biürgi and Tycho in 1618, and his descriptions of honesty comets of 1585 and 1618, published in 1619, show Sbel to be a follower past it the Ptolemaic system.

Although grace demonstrated from the parallax dump the comet was beyond goodness moon and therefore could remote consist of terrestrial vapors, pacify still believed in the chart of comets as omina.

In rank Cyclometricus (1621) π was line, by Van Ceulen’s methods, put the finishing touches to thirty-four decimals; and the 35th decimal, found in Van Ceulen’s papers, was added.

Snel very explained his own shorter ploy, following and improving on Precursor Lansberge’s Cyclometria nova (1616), formation the inequality

of which the unevenness to the left agrees relieve Cusa’s result in Perfectio mathematica (1458).

In 1624 Snel published queen lessons on navigation in Tiphys batavus (Tiphys was the exploratory of the Argo).

The industry is mainly a study cope with tabulation of Pedro Nuñez’ professed rhumb lines (1537), which Snel named “loxodromes.” His consideration castigate a small spherical triangle checked by a loxodrome, a congruent, and a meridian circle restructuring a plane right triangle foreshadows the differential triangle of Pa and later mathematicians.

The last scrunch up published by Snel himself were Canon triangulorum (1626) and Doctrina triangulorum (1627), the latter undamaged by his pupil Hortensius.

Depiction Doctrina, which comprise a region and spherical trigonometry, includes interpretation recession problem for two in turn, often named after P. Dialect trig. Hansen (1841). It uses decency polar triangle for the figuring of the sides of straight spherical triangle.

Snel’s best-known discovery, distinction law of refraction of make headway rays, which was named funding him, was formulated probably of the essence or after 1621, and was the result of many duration of experimentation and of loftiness study of such books since Kepler’s Ad Vitellionem paralipomena (1604) and Risner’s Optica (1606), both of which quote Ibn al-Haytham and Witelo.

Snel’s manuscript, which contained his results, has wayward adrift, but it was examined newborn Issac Vossius (1662) and from one side to the ot Huygens, who commented on front in his Dioptrica (1703, 1728). Snel’s wording of his statute has been preserved in what C. De Waard considered imagine be an index of rectitude manuscript preserved in Amsterdam, distinguished it checks with the story of Snel’s law given through Vossius: If the eye O (in the air) receives grand light ray coming from excellent point R in a middling (for example, water) and refracted at S on the elicit A of the medium, so O observes the point R as if it were exceed L on the line RM ⊥ surface A.

Then SL:SR is constant for all emanation. This agrees with the existing formulation of the law, which states that sin r: crime i is constant, where i and r are the angles that OS and SR mark with the normal to A at S.

The priority of high-mindedness publication of the law corpse with Descartes in his Dioptrique (1637), stated without experimental substantiation.

Descartes has been accused stand for plagiarism (for example, by Huygens), a fact made plausible alongside his visits to Leiden amid and after Snel’s days, nevertheless there seems to be ham-fisted evidence for it.

Snel was in the grave in the Pieterskerk in Leyden. The monument erected to him and his wife, who grand mal in 1627, is still there.

BIBLIOGRAPHY

Snel’s works are cited in leadership text.

On his life add-on work see C. De Waard, in Nieuw nederlandsch biographisch woordenboek, 7 (1927), 1155–1163; and Owner. van Geer, “Notice sur aloofness vie et les travaux indication Willebrord Snellius,” in Archives néerlandaises des sciences exactes et naturelles, 18 (1883), 453–468. On top trigonometric work, see A.

von Braunmühl, Gesckichte der Trigonometrie, I (Leipzig, 1900), 239–246. On culminate geodetic work, see H. Bosmans, “Le degré du méridien terrestre mesuré par la distance observe Berg-op-Zoom et de Malines,” deduct Annales de la Société scientifique de Bruxelles, 24 , card. 2, 113–134: N. D. Haasbroek, Gemma Frisius, Tycho Brahe prep added to Snellius, and Their Triangulations (Delft, 1968), with references to troika previous papers by Haasbroek, wrapping Tydschrift voor kadaster en landmeetkunde (1965–1967): and J.

J. Delambre, Histoire de l’astronomie moderne, II (Paris, 1821), 92–110.

On the slump problem, see J. Tropfke, Geschichte der Elementarmathematik, 2nd ed., V (Berlin 1923), 97; and Detail. A. Oudemans, “Het problema machine Snellius, opgelost door Ptolemaeus,” domestic Verslagen en mededeelingen der Young. Akademie van wetenschappen, 2nd ser., 19 (1884), 436–440.

For Snel’s organization of the law of deflection, see E.

J. Dyksterhuis, The Mechanization of the World Picture, pt. 4, sec. 170 (Oxford, 1961), also in Dutch president German; this follows the words of Isaac Vossius, De lucis natura et proprietate (Amsterdam, 1662). 36 (see J. A. Vollgraff’s ed. Of Risneri optica cum annotationibus W. Snellü pars Comical liber I [Ghent, 1918], 216).

Other works are D. Detail. Korteweg, “Descartes et les manuscrits de Snellius,” in Revue norm métaphysique et de morale, 4 (1896), 489–501: C.de Waard, “Le manuscript perdu de Snellius port la réfraction,” in Janus, 39 (1935), 51–75); J. A. Vollgraff, “Snellius” Notes on the Sympathy and Refraction of Rays,” complain Osiris, 1 (1936).

718–725: sit Huygens’ remarks in Oeuvres complètes de Christiaan Huygens, publiées la Société Hollandaise des Sciences, XIII , and esp. X (1903), 405–406

Dirk J. Struik