Lagrange's 'Recherches sur la libration de la lune' - From the Principle of Least Action to Lagrange's Principle

摘要

Among the variety of successful eighteenth century contributions, Lagrange's first paper on the moon's libration contains a breakthrough in analytical mechanics. Though it is his very own achievement, Lagrange himself was of course not isolated. Being aware of the results of his predecessors, and being in contact with his scientific contemporaries, he was well prepared for such ground-breaking insight, embedded in the cultural-philosophical surrounding of his time. Behind every named formula and equation there was or is, even in our computer dominated times, always a thinking and feeling human - a fact that we "users", still conneced to our scientific ancestors, should be well aware of. The historical background, however, is not only fascinating but also yields real benefits: "As far as I studied the basic contributions of our great masters I got insight and understanding which was far beyond everything which could be extracted from secondary sources" says Wilhelm Ostwand (1855-1932). The formerly tedious search for these sources has become comfortable with the rise of the internet. The corresponding addresses were added to the reference list in order to inspire further reading.