Simon Stevin
From Academic Kids

Simon Stevin (1548/49 – 1620) was a Belgian mathematician and engineer. He was active in a great many areas of science, both theoretical and practical, but may be best known for his translation of various mathematical terms into common Dutch language, make it the only European language for which the word for mathematics was not derived from the Latin.
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Biography
Stevin was born in Bruges, Flanders (now Belgium). Of the circumstances of his life very little is recorded; the exact day of his birth and the day and place of his death (The Hague or Leiden) are alike uncertain. It is known that he left a widow with two children; and one or two hints scattered throughout his works inform us that he began life as a merchant's clerk in Antwerp, that he travelled in Poland, Denmark and other parts of northern Europe, and that he was intimate with Prince Maurice of Nassau, who asked his advice on many occasions, and made him a public officer—at first director of the socalled "waterstaet" (the government for water affairs), and afterwards quartermastergeneral.
In Bruges there is a Simon Stevin Square which contains his statue by Eugen Simonis.
Discoveries and inventions
His claims to fame are varied. His contemporaries were most struck by his invention of a carriage with sails, a little model of which was preserved at Scheveningen till 1802. The carriage itself had been lost long before; but we know that about the year 1600 Stevin, with Prince Maurice of Orange and twentysix others, made use of it on the seashore between Scheveningen and Petten, that it was propelled solely by the force of the wind, and that it acquired a speed which exceeded that of horses.
Philosophy of science
Another idea of Stevin, for which even Hugo Grotius gave him great credit, was his notion of a bygone age of wisdom. The goal to be aimed at is the bringing about of a second age of wisdom, in which mankind shall have recovered all its early knowledge. The fellowcountrymen of Stevin were proud that he wrote in their own dialect, which he thought fitted for a universal language, as no other abounded like Dutch in monosyllabic radical words.
Geometry and physics
Stevin was the first to show how to model regular and semiregular polyhedra by delineating their frames in a plane. Stevin also distinguished stable from unstable equilibrium. He proved the law of the equilibrium on an inclined plane.
He demonstrated before Pierre Varignon the resolution of forces, which, simple consequence of the law of their composition though it is, had not been previously remarked.
He discovered the hydrostatic paradox that the downward pressure of a liquid is independent of the shape of the vessel, and depends only on its height and base.
He also gave the measure of the pressure on any given portion of the side of a vessel. He had the idea of explaining the tides by the attraction of the moon. In 1586 he demonstrates that two objects of different weight fall with the same speed.
Fortifications
Stevin seems to be the first who made it an axiom that strongholds are only to be defended by artillery, the defence before his time having relied mostly on small firearms.
He was the inventor of defence by a system of sluices, which proved of the highest importance for the Netherlands.
His plea for the teaching of the science of fortification in universities, and the existence of such lectures in Leiden, have led to the impression that he himself filled this chair; but the belief is erroneous, as Stevin, though living at Leiden, never had direct relations with its university.
Bookkeeping
Bookkeeping by double entry may have been known to Stevin as clerk at Antwerp either practically or through the medium of the works of Italian authors like Luca Pacioli and Gerolamo Cardano. He, however, was the first to recommend the use of impersonal accounts in the national household. He practised it for Prince Maurice, and recommended it to Sully, the French statesman.
Decimal fractions
His greatest success, however, was a small pamphlet called De Thiende ('the tenth'), first published in Dutch in 1586, and not exceeding seven pages in the French translation.
Decimal fractions had been employed for the extraction of square roots some five centuries before his time, but nobody before Stevin established their daily use; and so well aware was he of the importance of his innovation that he declared the universal introduction of decimal coinage, measures and weights to be only a question of time, in which he proved right.
His notation is rather unwieldy. The point separating the integers from the decimal fractions seems to be the invention of Bartholemaeus Pitiscus, in whose trigonometrical tables (1612) it occurs and it was accepted by John Napier in his logarithmic papers (1614 and 1619).
Stevindecimal_notation.png
image:Stevindecimal notation.png
Stevin printed little circles round the exponents of the different powers of onetenth. The fact that Stevin meant those encircled numerals to denote mere exponents is evident from his employing the very same sign for powers of algebraic quantities. He does not even avoid fractional exponents, and is ignorant only of negative exponents.
Stevin wrote on other scientific subjects—optics, geography, astronomy—and a number of his writings were translated into Latin by W. Snellius (Willebrord Snell). There are two complete editions in French of his works, both printed at Leiden, one in 1608, the other in 1634.
Neologisms
Stevin thought Dutch to be an excellent language for scientific writing, and he translated a lot of the mathematical terms to Dutch. As a result, Dutch is the only Western European language that has a lot of mathematical terms that do not stem from Latin, including its name, which in Dutch is called wiskunde.
His eye for the importance of having the scientific language be the same as the language of the craftsmen may show from the dedication of his book De Thiende ('The Disme'): 'Simon Stevin wishes the stargazers, surveyors, carpet measurers, body measurers in general, coin measurers and tradespeople good luck.' Further on in the same pamphlet, he writes: "[this text] teaches us all calculations that are needed by the people without using fractions. One can reduce all operations to adding, subtracting, multiplying and dividing with integers."
The words he invented evolved: 'aftrekken' (subtract) and 'delen' (divide) stayed the same, but over time 'menigvuldigen' became 'vermenigvuldigen' (multiply, the added 'ver' has no meaning) and 'vergaderen' became 'optellen' (add).
The word 'zomenigmaal' (quotient lit. 'that many times') has become the perhaps less poetic 'quotiënt' in modern day Dutch.
Publications
Amongst others, he published:
 Tafelen van Interest (Tables of interest) in 1582;
 Problemata geometrica in 1583;
 La Theinde (The tenth) in 1585 in which decimals were introduced in Europe;
 La pratique d'arithmétique in 1585;
 L'arithmétique in 1585 in which he presented a uniform treatment for solving algebraic equations;
 De Beghinselen der Weegconst in 1586;
 De Beghinselen des Waterwichts (Principles on the weight of water) in 1586 on the subject of hydrostatics;
 Vita Politica. Named Burgherlick leven (Civil life) in 1590;
 De Sterktenbouwing (The construction of fortifications) published in 1594;
 De Havenvinding (Position finding) published in 1599;
 De Hemelloop in 1608;
 Wiskonstighe Ghedachtenissen (Mathematical Memoirs). This included earlier works like De Driehouckhandel (Trigonometry), De Meetdaet (Practice of measuring), and De Deursichtighe (Perspective);
 Castrametatio, dat is legermeting and Nieuwe Maniere van Stercktebou door Spilsluysen (New ways of building of sluices) published in 1617;
 De Spiegheling der Singconst (Theory of the art of singing).
External links
 Template:MacTutor Biography
 [1] (http://home.planet.nl/~hopfam/ThiendeMenu.html) contains an HTML version (including hyperlinks to explanations) of De Thiende and its translations into English, French and Swedish, and scans of these books
 [2] (http://home.planet.nl/~hopfam/Stevin.html) contains a lot more information about Simon Stevin
 [3] (http://www.newadvent.org/cathen/14293b.htm) is the text of the Catholic Encyclopedia about Stevin. The author can hardly conceal his admiration, and for the rest the article is mostly a bibliography of Stevin's work.
 [4] (http://3quarksdaily.blogs.com/3quarksdaily/2005/05/monday_musing_s.html) is a short essay on Simon Stevin by S. Abbas Raza at 3 Quarks Daily (http://3quarksdaily.com)
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