Ueber eine Verbesserung der Wien’schen Spectralgleichung [On an improvement of Wien's spectral equation]
EXTREMELY RARE FIRST PRINTING IN ORIGINAL WRAPPERS OF ONE OF THE DEFINING DOCUMENTS OF QUANTUM THEORY: THE FIRST PRESENTATION OF PLANCK’S LAW OF BLACKBODY RADIATION: "a discovery that opened the way to the development of the quantum theory and provided the initial formulation for that theory”.
Planck’s “thesis work on the second law of thermodynamics ultimately became the basis of the research that led Planck to discover the quantum of action - now known as Planck's constant - in 1900. In late 1859, Kirchhoff had defined a black body as an object that is a perfect emitter and absorber of radiation. By the 1890s, various experimental and theoretical attempts had been made to determine its spectral energy distribution - the curve displaying how much radiant energy is emitted at different frequencies for a given temperature of the black body.
“Planck was especially intrigued by the formula found in 1896 by his colleague Wilhelm Wien, and he made a series of attempts to derive "Wien's law" on the basis of the second law of thermodynamics. By October 1900, however, other colleagues had conducted additional experiments and found definite indications that Wien's law, while valid at high frequencies, broke down completely at low frequencies. So Planck went back to work. He knew that the entropy of the radiation had to depend mathematically upon its energy in the high-frequency region if Wien's law held there. He also saw what this dependence had to be in the low-frequency region in order to reproduce the experimental results there. He guessed, therefore, that he should recombine these two expressions in the simplest possible way, and thus transform the result into a formula relating the energy of the radiation to its frequency.
“Planck presented this latest formulation at a meeting of the German Physical Society on October 19, 1900, [the paper offered here] which was hailed as indisputably correct. But to Planck, it was simply a ‘lucky guess,’ and he set about deriving the formulation from first principles. By December 14, 1900, he had succeeded in doing so, but only by introducing what was to prove a revolutionary concept in physics: the oscillators comprising the black body and re-emitting the radiant energy incident upon them could not absorb this energy continuously, but only in discrete amounts, or quanta of energy.
“This concept of energy quanta conflicted fundamentally with all past physical theory, and its importance was not fully appreciated at first, even by Planck himself, who was something of a reluctant revolutionary. However, the evidence for its validity gradually became overwhelming as its application accounted for many discrepancies between observed phenomena and classical theory, among them Einstein's explanation of the photoelectric effect. And in 1918 Planck's fundamental contribution was recognized with the awarding of the Nobel Prize in Physics, "for the discovery of energy quanta." (American Physical Society, “This Month in Physics History, October 1900: Planck’s Formula for Black Body Radiation”). Pat Langley, et al., Scientific Discovery: Computational Explorations of the Creative Processes.
IN: Verhandlungen der Deutschen Physikalischen Gesellschaft im Jahre 1900. Jahrg. 2. Nr. 13.; pp. 202-204. Leipzig: Johann Ambrosius Barth, 1900. Octavo, original green wrappers rebacked; custom box. Chip to top edge of front wrapper. A beautiful, clean copy without any institutional stamps of one of the foundational papers of quantum theory.