Remarking upon the popular appeal of most of the lectures, a contemporary observer noted that while many listeners might prefer to hear Professor Tyndall expound on the acoustic opacity of the atmosphere, "those of a higher and drier turn of mind experience ineffable delight when Professor Sylvester holds forth on the conversion of circular into parallel motion."[44] [Footnote 44: Bernard H. Becker, _Scientific London_, London, 1874, pp. 45, 50, 51.] Sylvester's aim was to bring the Peaucellier linkage to the notice of the English-speaking world, as it had been brought to his attention by Chebyshev--during a recent visit of the Russian to England--and to give his listeners some insight into the vastness of the field that he saw opened by the discovery of the French soldier.[45] [Footnote 45: Sylvester, _op. cit._ (footnote 41), p. 183; _Nature_, November 13, 1873, vol. 9, p. 33.] "The perfect parallel motion of Peaucellier looks so simple," he observed, "and moves so easily that people who see it at work almost universally express astonishment that it waited so long to be discovered." But that was not his reaction at all. The more one reflects upon the problem, Sylvester continued, he "wonders the more that it was ever found out, and can see no reason why it should have been discovered for a hundred years to come. Viewed _a priori_ there was nothing to lead up to it. It bears not the remotest analogy (except in the fact of a double centring) to Watt's parallel motion or any of its progeny."[46] [Footnote 46: Sylvester, _op. cit._ (footnote 41), p. 181.] It must be pointed out, parenthetically at least, that James Watt had not only had to solve the problem as best he could, but that he had no inkling, so far as experience was concerned, that a solvable problem existed.