Ultraviolet radiation is generally considered to have been discovered by Johann Wilhelm Ritter in 1801. In this article, we study the reception of Ritter’s experiment during the first decade after the event—Ritter’s remaining lifetime. Drawing on the attributional model of discovery, we are interested in whether the German physicists and chemists granted Ritter’s observation the status of a discovery and, if so, of what. Two things are remarkable concerning the early reception, and both have to do more with neglect than (...) with reception. Firstly, Ritter’s observation was sometimes accepted as a fact but, with the exception of C. J. B. Karsten’s theory of invisible light, it played almost no role in the lively debate about the nature of heat and light. We argue that it was the prevalent discourse based on the metaphysics of Stoffe that prevented a broader reception of Ritter’s invisible rays, not the fact that Ritter himself made his findings a part of his Naturphilosophie. Secondly, with the exception of C. E. Wünsch’s experiments on the visual spectrum, there was no experimental examination of the experiment. We argue that theorizing about ontological systems was more common than experimenting, because, given its social and institutional situation, this was the appropriate way of contributing to physics. Consequently, it was less clear in 1810 than in 1801 what, if anything, had been discovered by Ritter.Keywords: Johann Wilhelm Ritter; Carl Johann Bernhard Karsten; Christian Ernst Wünsch; Ultraviolet radiation; Conceptions of heat and light. (shrink)

Innovatory advances by outsiders: The example of the amateur astronomer William Herschel. — Every scientific experience and perception has been gained from within a particular historical situation constituted by numerous components, both internal and external to a particular science, called praesentabilia (Präsentabilien). They enable and determine the scope and the experiental pale of any given science as well as its way and method of acquiring experience and knowledge. The interaction of such praesentabilia forms, what may be called the Historische Erfahrungsraum (...) (‘historical field of experience’), which each individual and/or (greater/smaller) group shares in respectively. A scientific (cultural, religious, social, disciplinal, etc.) community may be said to exist whereever the intersection of the various sets of praesentabilia making up its members' fields of experience comprises a minimum standard of praesentabilia that form this community, thus establishing its particular Historische(n) Erfahrungsraum. As long and as far someone outside the disciplinal community could acquaint himself with its praesentabilia in a selftaught manner, there will be outsiders and amateurs, who, while lacking any regular (and one‐sided) education and training, yet owning some extra praesentabilia, would be in a position to bring in novel methods of thinking and unconventional perceptions. There may be several reasons for this: (1) because they study fields that are not yet or no longer present in the disciplinal community, or (2) because they are not bound to the usual (uniform and standardized) instrumentation, or (3) because their social status does not seem from the professional scientific community (nor from the socio‐political community, conditional to the former's existence). Conversely they feel not being bound by the rules, the expectations and the aims posited by that scientific community. Since the disciplinal community lacks the praesentabilia that are prerequisite to fully understanding the outsider and amateur, he, in turn, has to overcome much more difficulties, till his innovatory perceptions are acknowledged. On the other hand, whenever his new methods, instruments or points of view prove to be helpful in solving an old problem of the disciplinal community, this solution will generally soon be acknowledged, in case its reproduction is sufficiently guaranteed by the traditional methods and by the usual instruments. Eventually the acknowledgement may lead to the approbation and the acceptance of the said methods, instruments and points of view, because the solution offered has by then become a praesentabile integral to the disciplinal community.The life and career of an outsider and amateur, like William Herschel, is a good instance of a whole range of potentialities of such innovatory advances. Considering these points, the paper deals with several aspects of Herschel's work: his new method of reviewing the heavens (Himmelsdurchmusterung) linked to his novel telescopes, — his discovery of the planet Uranus, — his discovery and verification of the existence of physical double stars, — his assumption of historicity and development of cosmic objects, — his determining the shape of the Milky Way by means of a primary method of stellar statistics, ‐ his discovery and determination of the sun's peculiar motion, ‐ and his discovery of the infra‐red radiant heat continuing the spectrum of the visible light. (shrink)