In 1827 part of Plateau’s research was published in Quetelet’s _Correspondance Mathématique et Physique_. Quetelet (1796–1874) was a pioneer in statistics and Plateau’s professor at the Royal College, and also taught at the Museum of Science and Letters in Belgium. The next year, 1828, Plateau sent another communication to M. Quetelet on the appearances produced by two lines turning around a point with uniform motion. In that letter Plateau referred to the work of Roget on persistence of vision published in the _Philosophical Transactions_ of the Royal Society, London, 1824. Peter Mark Roget (1779–1869), English doctor best known for his _Thesaurus of English Words and Phrases_, combined his medical work with interest in the sciences. On December 9, 1824, he read, at the Royal Society, a paper called, “Explanation of an optical deception in the appearance of the spokes of a wheel seen through vertical apertures.” Roget pointed out that the phenomenon had been noted but not explained by an anonymous contributor who signed himself “J. M.” in the _Quarterly Journal_ of December 1, 1820. “J. M.” commented on the curvature of spokes when a wheel is in motion and is viewed through a series of vertical bars. Everyone has noted the strange rotations of motor car wheels when viewed under certain conditions, as in the modern motion picture. “J. M.” pointed out that at times the wheel appeared to rotate backwards; at other times, forward and still again seem to stand still. A nod of praise should be bestowed towards “J. M.” (these are not the initials of any of the better known English scientists of the period). Ten years later the great Faraday confessed he did not know the identity of this man who had stimulated those investigations which we now know led directly to the first actual motion pictures formed from hand-drawn designs. Roget, in 1824, noted that a certain velocity and a certain amount of light were necessary before the “wheel phenomenon” was visible--both speed of motion and bright light source are necessary for the motion picture illusion. Roget said, “It is evident from the facts above stated that the deception in the appearance of the spokes must arise from the circumstances of separate parts only of each spoke being seen at the same moment; the remaining parts being concealed from view by the bars” (equivalent to the shutters in the motion picture machine). Roget continued, “so that it is evident that the several portions of one and the same line, seen through the intervals of the bars, form on the retina the images of so many different radii.” Roget remarked that the illusion was the same as when a bright object is whirled in a circle--“an impression made by a pencil of rays on the retina, if sufficiently vivid, will remain for a certain time after the cause has ceased.”