Imagination and Intuition: The Origins of the Old Quantum Theory

1900 was a fundamental year for describing the black-body spectrum, as two new theoretical laws were given: one obtained by Lord Rayleigh[aut]Rayleigh, John William Strutt (completely based on a classic model and refined in 1905 by Rayleigh himseld and, independently, also by J. H. Jeans[aut]Jeans, James Hopwood), and one derived by M. Planck, with[aut]Planck, Max its ad hoc quantization hypothesis. The latter has historically been posed as the starting point of the so-called old quantum theory. In this chapter, we will discuss both.