Kepler's laws of planetary motion formula_16 The area enclosed by the elliptical orbit is formula_17 So the period formula_18 satisfies and the mean motion of the planet around the Sun satisfies This captures the relationship between the distance of planets from the Sun, and their orbital periods. Kepler enunciated in 1619 this third law in a laborious attempt to determine what he viewed as the "music of the spheres" according to precise laws, and express it in terms of musical notation. So it was known as the "harmonic law". Using Newton's Law of gravitation (published 1687), this relation can be found in the case of
Valerio-Horatian Laws on the plebiscites, there were three instances of such law. There were two other laws on appeal which were proposed by two consuls who were also members of the Valeria family, one by Publius Valerius Publicola in 509 BC and one by Marcus Valerius Corvus in 300 BC. Two other laws which provided for the plebiscites to be binding on the whole people were also proposed, one by Quintus Publilius Philo in 339 BC and one by Quintus Hortensius in 287 BC. This has led some historians to argue that in both cases the first and second laws are unhistorical