De Thiende

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II. Biography and bibliography on Simon Stevin

In his book on Simon Stevin, E.J. Dijksterhuis provides a most detailed biography (a, pp. 1-32). From this biography to which may be referred, we here mention the following.

Simon Stevin was born, most probably in 1548, at Bruges in Flandres. Nothing is known about his youth. After administrative activities in Antwerp and Bruges (1577) he settled at Leyden in 1581. Suppositions are made about journeys through Poland, Prussia and Norway but about this nothing can be said with certainty. He was matriculated as a student in the university of Leyden on February 16th, 1583. Simon Stevin had four children. As to his marriage we only know of a notice of marriage with Catherina Cray at Leyden on April 10th 1616 so at the age of 68, but Simon Stevin had children already before 1616¹⁰⁾. He died in 1620; we don't know the exact date nor the place but it happened between February 20th and April 8th and most probably in the Hague. From as early as 1593 Simon Stevin was in close relation with Prince Maurits whom he

10) These data are from E.J. Dijksterhuis. A.J.J. van de Velde, however, states (p. 6) a marriage ca. 1608.

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instructed in various subjects (see Wisconstighe Ghedachtenissen 1605-1608) and for whom he constructed his famous sailing-car.

In 1600 he was asked to compose an instruction for a school of engineers, which school was intended as a part of Leyden-university.

Stevin's first books were published in Antwerp¹¹⁾ viz. Tafelen van Interest 1582 and Problemata Geometrica 1583? Practically all his later works appeared at Leyden: Dialectike 1585, De Thiende 1585, L' Arithmetique 1585 (the second part of this book has the new title La Pratique d' Arithmetique), De Beghinselen der Weeghconst together with De Weegdaet and De Beghinselen des Waterwichts 1586, Vita politica. Het Burgherlick Leven 1590, Appendice algebraique 1594, Stercktenbouwing 1594, De Havenvinding 1599, Wisconstighe Ghedachtenissen 1605-1608. One single book, his last, was published at Rotterdam viz. Castrametatio, dat is Legermeting together with Nieuwe Maniere van Sterctebou, door Spilsluysen 1617.

Then, published posthumously by his second son Hendrik, Materiae Politicae, Leyden 1649, and the books VI, X and XI in Hendrik's own Wisconstich Filosofisch Bedryf, Leyden 1667. As a collection of some of Stevin's works Les Oeuvres Mathematiques was published by Albert Girard, Leyden 1634.

11) We only have mentioned first editions. But there are many reprints and translations; see: E.J. Dijksterhuis and A.J.J. van de Velde.

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Before discussing the contents of De Thiende, we would pay attention to some facts which the reader of De Thiende will come across and which are characteristic of the author.

In the development of sciences we owe various new ideas and discoveries to Stevin, especially in the fields of mechanics and hydrostatics¹²⁾. But besides this he also deserves our praise for his very clear argumentation which makes his books very readable up to the present day. For an example we would point to pp. 13 and 14 of De Thiende, where Simon Stevin treats the addition of his decimals, arranged as follows:

1.	‘T'Ghegheven’ (The explication propounded), viz. three numbers with decimal parts.
2.	‘T'Begheerde’ (The explication required), to find their sum.
3.	‘Wercking’ (Construction) in which is denoted how one has to write down the given numbers and how to add them. We would remark that for the arithmetics of his day it was customary to treat only the ‘Wercking’, so the way how to proceed. Stevin, however, first exactly proposes the problem. He then gives the way how to solve it and after this he continues with what is usually lacking in older arithmetics viz. the:

12) See: J. de Smedt.

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4.	‘Bewys’ (Demonstration). It is demonstrated that the result in 3) is just the same as what would be found when adding the numbers after the decimals have been reduced into common fractions^13).
5.	‘Besluyt’ (Conclusion) in which Stevin remarks that ‘T'Begheerde’ by means of the ‘Wercking’ is solved in the right way^14).

We next point to the explanatory notes in the margins of some pages of De Thiende. These are Latin names of notions for which Stevin introduces new Dutch words:

page 3
proportio	evenredenheyt
terminus	paal (plural: palen)
page 5
materia	stoffe
definitio	bepalinghe
effectus	daet (genitive: daets)
astrologus	sterrekijcker
supputatio
astronomica	sterreconsts rekening
aequator	evenaer (genitive: evenaers)
polus	aspunt (genitive: aspunts)
page 6
progressio	voortganck

13) This, of course, is not a demonstration but only an example. See the quotations from A. Taquet in D.J. Struik b), p. 377.

14) These five steps are according to the classical method.

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page 20
tabula arcuum et
chordarum	boogpeestafel
multinomii
numeri	veelnamighe ghetalen
page 28
hypothesis	ghestelde
page 30
gradus	trap (plural: trappen).

In his other works Stevin proposes far more new Dutch words. Many of them are now common in the Dutch language. Especially in mathematics Dutch has some typical words originating in Stevin for which words other languages still have the Latin expressions. As the nicest of these words may be considered ‘evenredig’, the adjective form with the substantive ‘evenredigheid’ and ‘evenwijdig, evenwijdigheid’.

‘Evenredigheid’ is the Dutch word for proportionality. It can be translated into English by ‘equality of two ratios’ and from this it appears how well the Dutch word expresses the nature of what is intended.

‘Evenwijdig’ is the Dutch word for parallel; it expresses the property that the points on one of two parallel lines have equal distances to the other¹⁵⁾.

15) Also originating in Stevin are (among others): wiskonst (knowledge of wisdom, mathematics), meetkonst (knowledge of measure, geometry), letterkonst (knowledge of letters, literature), bewijskonst (knowledge of demonstration, logic). See: A.J.J. van de Velde, p. 8.

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To Stevin this presentation of new Dutch words not only was a consequence of his love for a pure Dutch language but he also felt deeply convinced that of all languages Dutch was by far the best for scientific purposes. We have to memorize this when reading on page 32 of De Thiende:

... in onse Duytsche Tale (dat is ... uytghegheven) ...
(... in our vulgar German language, which is the most rich adorned and perfect tongue of all other, & of the most singularity, of which we attend a more abundant demonstration than Peter and John have made thereof in the Bewysconst and Dialectique, lately divulged) ...

At the end of this quotation Stevin refers to a dialogue between Ian and Pieter occurring in Dialectike 1585 in which dialogue Ian (obviously Stevin himself) argues the ability of the Dutch language for scientific purposes. Stevin also alludes to a new demonstration of this ability; here he points forward to ‘Simon Stevins Vytspraeck vande Weerdicheyt der Dvytsche Tael’ (Simon Stevin's Discourse on the worth of the Dutch language) occuring in the introduction to De Beghinselen der Weeghconst 1586¹⁶⁾. In this he points, among other

16) See: The principal works of Simon Stevin I, pp. 59-93.

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things, to the fact that there are far more monosyllables in Dutch than are in Latin or Greek; this indicates the high level of the Dutch language for the chief purpose of a language is a short representation of an idea¹⁷⁾.

17) As to the other arguments of Stevin and an elaborate discussion of all this, see E.J. Dijksterhuis a), pp. 298-320.