[Footnote 79: Reuleaux, _op. cit._ (footnote 68). This was not the last of Reuleaux's books. His trilogy on kinematics and machine design is discussed by De Jonge, _op. cit._ (footnote 78).] 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 clearness. 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.[80] [Footnote 80: Reuleaux, _op. cit._ (footnote 68), p. 23.] Reuleaux'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 translation.[81] [Footnote 81: _Ibid._, p. iii.] The book was enthusiastically reviewed by the weekly London journal _Engineering_,[82] 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."[83] Indeed, the fresh and sharp ideas of Reuleaux were somewhat clouded by a long (600-page) presentation; and his kinematic notation, which required another attempt at classification, did not simplify the presentation of radically new ideas.[84] [Footnote 82: _Engineering_, _loc. cit._ (footnote 77).] [Footnote 83: _The Engineer_, London, March 30 and April 13, 1877, vol. 43, pp. 211-212, 247-248.] [Footnote 84: It is perhaps significant that the first paper of the First Conference 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 Mechanisms," _Applied Mechanics Reviews_, September 1959, vol. 12, pp. 587-590.] [Illustration: Figure 31.--Alexander Blackie William Kennedy (1847-1928), translator of Reuleaux' _Theoretische Kinematik_ and discoverer of Kennedy's "Law of Three Centers." From _Minutes of the Proceedings of the Institution of Civil Engineers_ (1907, vol. 167, frontispiece).]