On the relativity of motion in Leonhard Euler's science
In his Mechanica of 1736, Euler turned the concept of relativity of motion into an effective tool for the development of rational mechanics. The same principle was used in the Scientia Navalis of 1741: investigating the motion of a ship driven by the wind, Euler suppressed the translatory motion by assuming that its center of gravity was at rest, and so he was able to describe only its rotational motion around an axis through its center of mass, assuming that both motions were independent of one another. This procedure of splitting the two types of motion by using the concept of relativity in order to study exclusively the rotatory motion was also employed by Euler in a paper of 1744, dealing with the motion of bars linked together and moving on a frictionless plane. In the second part of his article, the author shows that the limits of the principle of relativity emerged when Euler moved from mechanics to optics. It turned out that it was too difficult to apply the principle of relativity to optical phenomena like aberration if the latter were to be treated through the wave theory of light. Thus quite pragmatically Euler temporarily gave up the ether itself together with wave optics and decided to explain aberration by a corpuscular model, since this theory, while less sound than wave optics, allowed him safely to use the principle of relativity and gave a good estimate of aberration.
scientific article; zbMATH DE number 1394855