but it was an original, thoughtful work that departed 

 in spirit if not always in method from its predecessors. 

 Principles of Mechanism was a prominent landmark 

 along the road to a rational discipline of machine- 

 kinematics. 



A phenomenal engineer of the 19th century 

 was the Scottish professor of civil engineering at the 

 University of Glasgow, William John MacQuorn 

 Rankine. Although he was at the University for 

 only 17 years — he died at the age of 52, in 1872 — 

 he turned out during that time four thick manuals 

 on such diverse subjects as civil engineering, ship- 

 building, thermodynamics, and machinery and mill- 

 work, in addition to literally hundreds of papers, 

 articles, and notes for scientific journals and the 

 technical press. Endowed with apparently boundless 

 energy, he found time from his studies to command 

 a battalion of rifle volunteers and to compose and 

 sing comic and patriotic songs. His manuals, often 

 used as textbooks, were widely circulated and went 

 through many editions. Rankine's work had a 

 profound effect upon the practice of engineering by 

 setting out principles in a form that could be grasped 

 by people who were dismayed by the treatment 

 usually found in the learned journals. 



When Rankine's book titled A Manual of Machinery 

 and Millwork was published in 1869 it was accurately 

 characterized by a reviewer as "dealing with the 

 principles of machinery and millworks, and as such it is 

 entirely distinct from [other works on the same sub- 

 ject] which treat more of the practical applications of 

 such principles than of the principles themselves." ^^ 



Rankine borrowed what appeared useful from 

 Willis' Principles of Mechanism and from other sources. 

 His treatment of kinematics was not as closely reasoned 

 as the later treatises of Reuleaux and Kennedy, which 

 will be considered below. Rankine did, however, for 

 the first time show the utility of instant centers in 

 velocity analysis, although he made use only of the 

 instant centers involving the fixed link of a linkage. 

 Like others before him, he considered the fixed link of 

 a mechanism as something quite different from the 

 movable links, and he did not perceive the possibilities 

 opened up by determining the instant center of two 

 movable links. 



Many other books dealing with mechanisms were 

 published during the middle third of the century, but 

 none of them had a discernible influence upon the 



advance of kinematical ideas."* The center of inquiry 

 had by the 1860's shifted from France to Germany. 

 Only by scattered individuals in England, Italy, and 

 France was there any impatience with the well- 

 established, general understanding of the machine- 

 building art. 



In Germany, on the other hand, there was a surge 

 of industrial activity that attracted some very able 

 men to the problems of how machines ought to be 

 built. Among the first of these was Ferdinand 

 Redtenbacher (1809-1863), professor of mechanical 

 engineering in the polytechnic school in Karlsruhe, 

 not far from Heidelberg. Redtenbacher, although he 

 despaired of the possibility of finding a "true system 

 on which to base the study of mechanisms," was 

 nevertheless a factor in the development of such a 

 system. He had young Franz Reuleaux in his classes 

 for two years, from 1850. During that time the older 

 man's commanding presence, his ability as a lecturer, 

 and his infectious impatience with the existing order 

 influenced Reuleaux to follow the scholar's trail that 

 led him to eminence as an authority of the first rank.'* 



Before he was 25 years old Franz Reuleaux pub- 

 lished, in collaboration with a classmate, a textbook 

 whose translated title would be Constructive Lessons for 

 the Machine Shop.'^ His several years in the workshop, 

 before and after coming under Redtenbacher's 

 influence, gave his works a practical flavor, simple 

 and direct. According to one observer, Reuleaux's 

 book exhibited "a recognition of the claims of practice 

 such as Englishmen do not generally associate with the 

 writings of a German scientific professor." " 



Reuleaux's original ideas on kinematics, which are 

 responsible for the way in which we look at mecha- 

 nisms today, were sufficiently formed in 1864 for him 

 to lecture upon them."* Starting in 1871, he pub- 



's E'ngiTOerin^, London, August 13, 1869, vol. 8, p. 111. 



'* Several such books are referred to by Reuleaux, op. cit. 

 (footnote 68), pp. 12-16. 



'° See Carl Weihe, "'Franz Reuleaux und die Grundlagen 

 seiner Kinematik," Deutsches Museum, Munich, Abhandlung 

 und Berkhte, 1942, p. 2; Friedrich Klemm, Technik: Eine 

 Geschichte ihrer Probleme, Freiburg and Munich, Verlag Karl 

 Alber, 1954, translated by Dorothea W. Singer as A History of 

 Western Technology, New York, Charles Scribner's Sons, 1959, 

 p. 317. 



"See Weihe, op. cit. (footnote 75), p. 3; Hans Zopke, "Pro- 

 fessor Franz Reuleau.x," Gassier' s Magazine, December 1896, 

 vol. 11, pp. 133—139; Transactions of the American Society of 

 Mechanical Engineers, 1904-1905, vol. 26, pp. 813-817. 



" Engineering, London, September 8, 1876, vol. 22, p. 197. 



'* A. E. Richard de Jonge, "What is Wrong with Kinematics 

 and Mechanisms?" Mechanical Engineering, April 1942, vol. 64, 

 pp. 273—278 (comments on this paper are in Mechanical Engi. 



PAPER 27: KINEMATICS FROM THE TIME OF WATT 



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