(b. Eschweiler, Germany, 30 September 1829; d. Berlin, Germany, 20 August 1905)
Reuleaux was significant in two respects. In engineering he is regarded as the founder of modern kinematics. In two highly original books on that subject he proposed a system of analyzing and classifying machinery that was philosophical in scope and that has proved remarkably durable. More generally, by virtue of a forceful and outgoing personality and a talent for publicity, he was recognized in Germany as the spokesman for engineers and for modern technology in general during the first two decades of the Second Empire, a period of rapid industrial growth.
Reuleaux was the fourth son of Johann Josef Reuleaux, one of the first steam engine manufacturers in the Rhineland and himself the son of a master engineer (Kunstmeister ) from Liège. The elder Reuleaux died when Franz was a child, and in 1839 his widow moved the family to Koblenz., where Franz attended school through the intermediate grades. In 1844 his stepfather, named Scholl, chief engineer of an ironworks, apprenticed the boy to a Koblenz iron foundry and machine shop, while himself instructing him in theoretical subjects. In 1846 Reuleaux joined his father’s factory at Eschweiler, now run by an uncle, first as a draftsman and later (1848) as a field engineer. In 1850 he enrolled at the Karisruhe Polytechnische Schule, where he studied for two years under Redtenbacher, one of the foremost engineering teachers of the day. In 1852 and 1853 Reuleaux studied at the universities of Berlin and Bonn, where, besides attending lectures on science, mathematics, and philosophy, he wrote, in collaboration with a fellow student, C. L. Moll, a brief treatise on the strength of materials and a long handbook of machine design. Since the latter contained materials from Karlsruhe lectures, he was accused of plagiarism by Redtenbacher, his former teacher; most leading engineers, however, judged the work useful and forgave him. Reuleaux spent the years 1854 and 1855 in Cologne, first as the manager of a factory and then as an independent consulting engineer.
In 1856 Reuleaux was named professor of machine design at the newly founded Swiss Federal Polytechnical Institute. After eight years in Zurich, he became professor of mechanical engineering at the Gewerbe Institut in Rerun in 1864; he served as director of that school from 1867 until, after merging with the Berlin Bauakademie, it was reorganized in 1879 into the Technische Hochschule at Charlottenburg. He was elected rector of the institution for several terms. He retired from teaching in 1896 and remained in Berlin until his death.
Reuleaux’s basic field was machine design. Besides a great number of minor publications on all aspects of this field, he wrote a handbook of machine design, Der Constructeur, highly popular at the time but later denounced as “a technological recipe book” (R. von Mises, 1929). Vithin the general field of machine design he discovered his own specialty in kinematics, with which his name is now permanently linked. Reuleaux had planned an exhaustive treatment of kinematics. The highly successful first volume on theoretical kinematics appeared in 1875; but a second volume, on the more technical and practical aspects. was published when Reuleaux’s influence was waning (1900) and received less notice. A projected third volume was never written.
The first volume, which had the greatest impact, is not an engineering book in the modern sense. Reuleaux saw its strongest points in logic and philosophy. Its subtitle, Gründzuge einer Theorie des Maschinenwesens, suggests the breadth of its ambitions. The volume consists of three parts. The first, in the tradition of Kachette, Borgnis, and Babbage, provides the logical and conceptual tools for analyzing and classifying machinery; prominent among them are the concepts of the kinematic pair and the kinematic chain, and a symbolic notation which Reuleaux hoped to employ algebraically in synthesizing mechanisms. The second part was devoted to the application of this conceptual apparatus to the task of “kinematic analysis,” which consisted of breaking down given machines into chains of abstract components in order to identify mechanisms that were kinematically equivalent. The third and shortest section is hardly more than a veiled admission of failure in attaining its declared objective of “kinematic synthesis” by means of systematic- deductive methods.
Although falling short of its objectives, Reuleaux’s kinematics was studied eagerly. It not only led to the cultivation of kinematics as an independent discipline, but also became particularly popular among nontechnical readers. When its fatal weakness, a total disregard for dynamic phenomena. was recognized, the reaction was strong enough to cause kinematics to he struck from the Berlin curriculum after Reuleaux’s retirement. Reuleaux’s system of classifying mechanisms, however, proved definitive; and modern kinematics acknowledges a large debt to him.
Reuleaux affected German engineering and industry by means other than his books. He corresponded with leading industrialists, such as Eugen Langen, who valued his advice: he had an important role in the founding of the Mannesmann steelworks; he worked hard for the passage of comprehensive German patent legislation. Of special interest to him were world exhibitions. He was a member of the juries of the expositions at Paris (1867), Vienna (1873), and Philadelphia (1876); and he also served as the German commissioner at Philadelphia, Sydney (1879), and Melbourne (1881).
Reuleaux was a prolific writer, and covered a broad spectrum. He wrote not only on all aspects of engineering but also on technology and civilization (translation in the 1890 Report of the Board of Regents of the Smithsonian Institution ), on the purity of the German language, and on technology and art; he also published a number of travel journals and a translation into German, in the original meter, of Longfellow’s Hiawatha.
After enjoying great prestige in the 1870’s and 1880’s, Reuleaux saw his influence decline. A younger and scientifically more refined generation of engineers recognized the weaknesses of his technical teachings, weaknesses amplified by the all-too-broad scope of his interests and his love of bold formulation. The dominance of kinematics had to give way to a fuller consideration of dynamic problems. A controversy arose among academic engineers, the opposing parties being identified by their espousal of theory and of practice. The proponents of “practice” eventually gained control of most German institutes of technology, while Reuleaux, a prominent “theorist,” spent his later years, especially after retirement, in increasing isolation.
I. Original Works. Bibliographies of Reuleaux’s works are in Poggendorff, III, 1111; IV, 1234–1235; V, 1040; and VI, 2157; and in Carl Weihe, Franz Reuleaux und seine Kinematik (Berlin, 1925). His books include Festigkeit der Materialien (Brunswick, 1853), written with C. L. Moll; Constructions-Lehre für den Maschinenbau (Brunswick, 1854), written with C L. Moll; Construction und Berechnung der für den Maschinenbau wichtigsten Federarten (Winterthur, 1857); Der Constructeur (Brunswick, 1861, 1865, 1872, 1889), English trans, by Henry H. Suplee as The Constructor: A Handbook of Machine Design (New York, 1893), also in French, Swedish, and Russian; Theoretische Kinematik: Gründzuge einer Theorie des Maschinenwesens (Brunswick, 1875), English trans. by Alexander B. W. Kennedy as The Kinematics of Machinery: Outlines of a Theory of Machines (London, 1876; repr. New York, 1963), also in French and Italian; Briefe aus Philadelphia (Brunswick, 1877); and Theoretische Kinematik, II, Die praktischen Beziehungen der Kinematik zu Geometric und Meehanik (Brunswick, 1900).
II. Secondary Literature. See Eugene S. Ferguson, “Kinematics of Mechanisms From the Time of Watt,” in Contributions from the Museum of History and Technology. U. S. National Museum Bulletin, 228, no. 27 (1962), 185 230; Wilhelm Hartmann, “F. Reuleaux,” in Zeitschrift des Vereins deutscher Ingenieure, 49 (1905), 1481–1482; and “Gedenkrede bei der Enthüllung des Denkmals fur Franz Reuleaux,” ibid, 57 (1913), 162–169; Heinrich Koch, “Franz Reuleaux und die Gründung der Mannes-mannröhren-Werke,” in Tradition, 5 (1960), 259–270; Alexander Lang, “Franz Reuleaux und die Maschinen-wissenschaft,” in Zeitschrift für Sociatwissenschaft, 8 (1905), 804–809; Otto Mayr, “Symbolsprachen für mechanische Systeme im 19. Jahrhundert,” in Technik-geschichte, 35 (1968), 223–240; R. von Miscs, “Franz Reuleaux,” in Zeitschrift für angewandte Mathematik und Mechanik, 9 (1929), 519; Wilhelm Oechsli, Geschichte der Gründung des Eidg. Polytechnikums mit einer Übersicht seiner Entwicklung 1855–1905 Frauenfeld, 1905), 179–182; Theodor Püschl, “Franz Reuleaux,” Karlsruher -demische Reden, no. 4 (1929); and Carl Weihe, Franz Reuleaux und seine Kinematik (Berlin, 1925); and “Franz Reuleaux und die Grundlagen seiner Kinematik,” in Abhandlungen und Berichte des Deutschen Museums, 14 (1942), 83–104.