BOOKS ON ARCHITECTURE
Author(s) 
Leclerc, Sébastien 
Title 
Pratique de la geometrie... 
Imprint 
Paris, T. Jolly, 1669 
Localisation 
Los Angeles, The Getty Research Institute, Besterman Collection, 3024011 
Subject 
Geometry 


Transcribed version of the text

French
To those interested in both the arts and the sciences in the 17th century, the careers of Abraham Bosse (1604 ?1676) and Sébastien Leclerc (16371714) offer some striking similarities and differences. Admittedly one was associated more with Louis XIII and Richelieu, the other with Louis XIV and Colbert, but they were both celebrated engravers whose work was very much sought out by their contemporaries. They were also scholars who became erudite surveyors, necessarily depending on perspective and architecture. They spent time with a number of scientists including Denis Dodart whose Mémoires pour servir à l’histoire des plantes, printed in 1686 by the Imprimerie Royale and illustrated by Leclerc, contains ten plates by Abraham Bosse. Their careers at the Royal Academy of Painting and Sculpture were more in contrast, for Bosse left the Compagnie, thus giving his blessing to his separation with Le Brun. But it was this same First Painter of the King who very quickly recognized Leclerc’s talent and presented him to the Académie in 1672 where he was admitted, says Jombert, “by unanimous consent, as an engraver [more exactly as draftsman and engraver]; at the same time he was named professor of geometry and perspective, with a pension of 300 livres”.
Just as Bosse was called upon when the Académie was founded to teach geometry and perspective there after his book came out on La manière universelle de Mr Desargues pour pratiquer la perspective(16478), in the same way La pratique de la géométrie sur le papier et sur le terrain by Sébastien Leclerc, its printing completed in November, 1668, dated 1669, had quite a bit to do with his nomination to the Académie three years later. In fact this publication, called the Petite géométrie by Leclerc , was tremendously successful. It was dedicated to the Marquis de Seignelay, the great Colbert’s son. That year Louis XIV permitted Colbert to bequeath all his posts to his son. The vignette above the dedication joins the Sun, the symbol of the king, and the garter snakes in Colbert’s coat of arms. It is not, as is often said, a book on perspective but an elementary book on geometry plainly aimed at teaching the young. Leclerc reminds one in his preface that geometry is necessary for astrologers, geographers, architects, engineers, “to people of quality whose birth commits them to making war” and to draftsmen. These last mentioned, he writes, “must know something of Geometry, since they can otherwise have no knowledge of Architecture or Perspective, two absolutely necessary parts of their Art”. But during that period numerous elementary books on geometry were available to the public. In the same niche, four years earlier, Bosse published his Traité des pratiques géométrales et perspectives enseignées à l’Académie, but Leclerc’s book was attractive due to its originality and its artistic perfection. For the first time, it would seem, a treatise on geometry clearly brought together on the one hand a mathematical text, certainly on an average level but still solid, and on the other, engravings of little landscapes decorated with pieces of architecture which are, says Edouard Meaume, “drawn and engraved so exactly and forcefully that art seems outdone”.
A 16page introduction with 16 plates presents geometry in a rather Euclidian form, with definitions, axioms and petitions. The geometric figures elucidating each mathematical page face each page and have fine or ornamental borders with sometimes little personages. This kind of presentation was not new even if Leclerc’s imagination and dexterity are already visible in it. The rest of the work is divided in five books on five geometric themes. A plate corresponds to each page of text, on which the geometric figures relating to the mathematical explanations appear in the upper part. In the lower part, and this is Leclerc’s originality, there is a vignette which has no connection with the text. They are little extremely amusing subjects, in their sweetness and their variety, wrote Jombert, who describes these engravings carefully (pp. 104124). Some of these subjects were composed very early in Metz even before Leclerc arrived in Paris in 1665. One might consider that they all constitute examples of architecture and subjects of imagination in which the linear and aerial perspectives are cleverly implemented and can be used by beginners as models. The mathematical content is not trifling: the first book describes lines in 14 classic propositions. The second book sets out 16 propositions on the construction of plane figures; proposition 13 gives the construction of an ellipse through the procedure called “paper strip”, but it is very far from Bosse’s scolarly propositions on conic sections. The third book treats the inscription of the figures in 15 propositions. One also finds there the approximate inscription of a circle in a heptagon after Dürer’s method (prop. 4), of an enneagon (prop. 5) and above all a hendecagon with a remarkable relative precision of 4 per 10,000 (prop. 6). The fourth book, more original, deals with drawing figures, like, for example, drawing an equilateral triangle within a pentagon (prop. 8). The fifth book has six very exact geometric solutions to problems on proportional lines but which could appear a little oldfashioned at that time.
By thus combining very serious remarks with attractive illustrations Sébastien Leclerc had a great commercial success. In that year, 1669, Colbert, a lover of fine arts, charmed by his talent, gave him lodging at the Gobelins which he kept all his life as well as a pension of 600 écus which linked him to the king’s service. A second edition enlarged by ten new plates (three of which were taken from Discours sur le point de vue of 1679) came out of the presses of Thomas Jolly in 1682, then a third edition, with seven new plates, was published at Jean Jombert’s presses in 1700.
This book was plagiarized many times, especially in London, but also in Lausanne, Amsterdam, Berne, Venice and Rome and translations in English, Latin, German and Italian were done. These editions appeared very early (as early as 1671 in London) and almost every decade during the beginning of the 18th century saw several publications. Let us point out, in order to show Sébastien Leclerc’s editorial posterity, a very late edition, in 1805, of Nattes’s Practical Geometry or introduction to Perspective Translated from the French of Le Clerc, in London, at W. Miller’s printing presses, which kept a large part of the mathematical content but in which Leclerc’s engravings were replaced by those by the draftsman John Claude Nattes and the draftsmanengraver William Henry Pyne.
JeanPierre Manceau (Tours) – 2016
Critical bibliography
C.A. Jombert. Catalogue raisonné de l’œuvre de Sébastien Le Clerc..., vol. 1, vol. 2, Paris, C.A. Jombert, 1774.
P.J. Mariette, Abecedario et autres notes inédites de cet amateur sur les arts et les artistes. Ouvrage publié... et annoté par... Ph. de Chennevières et A. de Montaiglon, Paris. J.B. Dumoulin, 1856, vol. 3, pp. 97112.
E. Meaume, 16371714 Sébastien Le Clerc et son œuvre gravé, Paris, Baur & Rapilly, 1877.
M. Préaud, Inventaire du fonds français. Graveurs du XVIIe siècle, Sébastien Leclerc,vol. 8.1; vol. 9.2, Paris, Bibliothèque nationale, 1980.
Sébastien Le Clerc, 16371714 [Catalogue of the exhibition organized by the Bibliothèque municipale de Metz, May 27July 26, 1980], Metz, Bibliothèque municipale de Metz, 1980.
