Figure 13. — ^James White's hypocycloidal 

 straight-line mechanism, about 1800. The 

 fly-weights (at the ends of the diagonal arm) 

 functioned as a flywheel. From James White, 

 A New Century of Inventions (Manchester, 1822, 

 pi. 7). 



result that the pivot, to which the piston rod was 

 connected, traced out a diameter of the large pitch 

 circle (fig. 1 3) . White in 1 801 received from Napoleon 

 Bonaparte a medal for this invention when it was 

 exhiijited at an industrial exposition in Paris.-' 

 Some steam engines employing White's mechanism 

 were built, but without conspicuous commercial 

 success. White himself rather agreed that while 

 his invention was "allowed to possess curious prop- 

 erties, and to be a pretty thing, opinions do not all 

 concur in declaring it, essentially and generally, 

 a good thing." ^^ 



The first of the non-Watt four-bar linkages ap- 

 peared shortly after 1800. The origin of the grass- 

 hopper beam motion is somewhat obscure, although 



2» H. W. Dickinson, "James White and His 'New Century of 

 Inventions,' " Transactions of the Newcomen Society, 1949—1951, 

 vol. 27, pp. 175-179. 



3" James White, A New Century of Inventions, Manchester, 1822, 

 pp. 30-31, 338. A hypocycloidal engine used in Stourbridge, 

 England, is in the Henry Ford Museum. 



n? 



s> 



TEJ 



Figure 14. — Freemantle straight-line linkage, 

 later called the Scott Russell linkage. From 

 British Patent 2741, November 17, 1803. 



it came to be associated with the name of Oliver 

 Evans, the American pioneer in the employm.ent of 

 high-pressure steam. A similar idea, employing an 

 isosceles linkage, was patented in 1803 by William 

 Freemantle, an English watchmaker (fig. \A)}^ 

 This is the linkage that was attributed much later 

 to John Scott Russell (1808-1882), the prominent 

 naval architect. ^- An inconclusive hint that 

 Evans had devised his straight-line linkage by 1805 

 appeared in a plate illustrating his Abortion of the 

 Toiing Steam Engineers Guide (Philadelphia, 1805), and 

 it was certainly used on his Columbian engine (fig. 

 15), which was built before 1813. The Freemantle 

 linkage, in modified form, appeared in Rees's Cyclo- 

 paedia of 1819 (fig. 16), but it is doubtful whether 

 even this would have been readily recognized as 

 identical with the Evans linkage, because the con- 

 necting rod was at the opposite end of the working 

 beam from the piston rod, in accordance with 

 established usage, while in the Evans linkage the 

 crank and connecting rod were at the same end of 

 the beam. It is possible that Evans got his idea from 

 an earlier English periodical, but concrete evidence 

 is lacking. 



If the idea did in fact originate with Evans, it is 

 strange that he did not mention it in his patent 

 claims, or in the descriptions that he published of his 



31 British Patent 2741, November 17, 1803. 



32 William J. M. Rankine, Manual of Machinery and Millwork, 

 ed. 6, London, 1887, p. 275. 



200 



BULLETIN 228: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



