lished his findings serially in the publication of the 

 Verein zur Beforderung des Gewerbefleisses in Preus- 

 sen (Society for the Advancement of Industry in 

 Prussia), of which he was editor. In 1875 these 

 articles were brought together in the JDOok that estab- 

 lished his fame — Theoretische Kinematik . . .'' 

 In the introduction of this book, Reuleaux wrote: 



In the development of every exact science, its substance 

 having grown sufficiently to make generalization possible, 

 there is a time when a series of changes bring it into clear- 

 ness. This time has most certainly arrived for the science of 

 kinematics. The number of mechanisms has grown almost 

 out of measure, and the number of ways in which they are 

 applied no less. It has become absolutely impossible still to 

 hold the thread which can lead in any way through this 

 labyrinth by the existing methods.* 



Reauleaux's confidence that it would be his own 

 work that would bring order out of confusion was well 

 founded. His book had already been translated into 

 Italian and was being translated into French when, 

 only a year after its publication, it was presented by 

 Prof. Alexander B. W. Kennedy in English trans- 

 lation." 



The book was enthusiastically reviewed by the 

 weekly London journal Engineering,^- and it was given 

 lengthy notice by the rival journal. The Engineer. The 

 editor of The Engineer thought that the mechanician 

 would find in it many new ideas, that he would be 

 "taught to detect hitherto hidden resemblances, and 

 that he must part — reluctantly, perhaps — with many 

 of his old notions." "But," added the editor with 

 considerable justice, "that he [the mechanician] would 

 suddenly recognize in Professor Reuleaux's 'kinematic 

 notation,' 'analysis,' and 'synthesis,' the long-felt want 

 of his professional existence we do not for a moment 

 believe." *^ Indeed, the fresh and sharp ideas of 

 Reuleaux were somewhat clouded by a long (600- 

 page) presentation; and his kinematic notation, which 



neering, October 1942, vol. 64, pp. 744-751); Zopke, op. cit. 

 (footnote 76), p. 135. 



" Reuleaux, op. cit. (footnote 68). This was not the last of 

 Reuleaux's books. His trilogy on kinematics and inachine de- 

 sign is discussed by De Jonge, op. cit. (footnote 78). 



*f Reuleaux, op. cit. (footnote 68), p. 23. 



8' Ibid., p. iii. 



^'^Engineering, loc. cit. (footnote 77). 



83 The Engineer, London, March 30 and April 13, 1877, vol. 

 43, pp. 211-212, 247-248. 



Figure 31. — Alexander Blackie William Ken- 

 nedy (1847-1928), translator of Reuleaux' 

 Theoretische Kinematik and discoverer of Ken- 

 nedy's "Law of Three Centers." From 

 Minutes oj the Proceedings oj the Institution of Civil 

 Engineers (1907, vol. 167, frontispiece). 



required another attempt at classification, did not sim- 

 plify the presentation of radically new ideas.'* 



Nevertheless, no earlier author had seen the problem 

 of kinematic analysis so clearly or had introduced so 

 much that was fresh, new, and of lasting value. 



Reuleaux was first to state the concept of the pair; 

 by his concept of the expansion of pairs he was able 

 to show similarities in mechanisms that had no appar- 

 ent relation. He was first to recognize that the fixed 

 link of a mechanism was kinematically the same as the 

 movable links. This led him to the important notion 

 of inversion of linkages, fixing successively the various 

 links and thus changing the function of the mecha- 



'*' It is perhaps significant that the first paper of the First Con- 

 ference on Mechanisms at Purdue University was Allen S. 

 Hall's "Mechanisms and Their Classification," which appeared 

 in Machine Design, December 1953, vol. 25, pp. 174-180. The 

 place of classification in kinematic synthesis is suggested in 

 Ferdinand Freudenstein's "Trends in Kinematics of Mecha- 

 nisms," Applied Mechanics Reviews, September 1959, vol. 12, 

 pp. 587-590. 



214 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



