Bringing sound into the laboratory: The Koenig Analyser

David Pantalony

The publication of Die Lehre von den Tonempfindungen (‘On the Sensations of Tone’) by Hermann von Helmholtz (1821-1894) in 1863 inspired the growth of experimental acoustics across Europe and North America, resulting in a proliferation of novel instruments for studying sound. The ‘Clang Analyser’, introduced by Rudolf Koenig (1832-1901) in 1865, was one of the earlier apparatus derived from the work of Helmholtz. It separated complex musical notes into their constituent sounds and then transformed these frequencies into their own distinct, visual flame patterns. In this paper I explore three features of Koenig’s remarkable invention. First, I describe the theories embodied within the analyser and its main component, the Helmholtz resonator; I then describe the significance of these new devices for the laboratory with accounts of how they were used in teaching and research. Second, the analyser illustrates Koenig’s talent for taking known yet little studied phenomena, and transforming them into credible phenomena for the laboratory. In particular, I discuss the development of the manometric flame capsule. Third, visualizing sound, mastered and pioneered by Rodolf Koenig, was a new and powerful trend in acoustics during this period. By examining developments in the analysis of compound tones, we obtain a clear case study of how acoustics rapidly adopted visual methods, moving away from reliance on the ear. My research into this history is based, in part, on the examination and operation of Koenig’s instruments at the University of Toronto and the Smithsonian Institution in Washington DC.

The Black Body - a revolutionary instrument

Dr Dieter Hoffmann

The 14th of December 1900 is regarded as the birthday of quantum theory, and its centenary will be celebrated all over the world. My talk will also honour this event, but I shall not speak on Planck’s derivation of a new radiation law and the introduction of a new constant of nature, the quantum of action. My talk will focus on the developments and, in particular, on the creation of a black body. The black body is crucial to the theory of heat radiation and its experimental proof, since the radiation theory was based on it from its beginning. But up to the mid-seventies there was no technical realization of a black body, which yields to a lot of theoretical uncertainties and experimental discrepancies concerning the laws of radiation. So far the first design of perfectly black bodies, starting with the work of Wilhelm Wien and Otto Lummer at Berlin’s Physikalisch-Technische Reichsanstalt, played a central part in the creation of the quantum theory and of the resulting scientific revolution. Describing the genesis of the design of different black bodies, I will demonstrate their importance and their revolutionary character for establishing precision measurement in the field of heat radiation as well as for the development of valid laws of radiation.

The historic value of trade catalogues

Bart Grob

Museums specialized in scientific instruments collect, if available, the catalogues of their makers. They tend to do this for different reasons. Most of them are practical. Catalogues are used to identify an instrument, to gather knowledge about technical aspects or design. Besides these practical reasons, catalogues may be collected for aesthetic reasons. The illustrations alone are worth collecting.

In this paper early 20th century manufacturer catalogues are studied to find more fundamental historic value for these sources. Using the development of the galvanometer as a case study, questions like: do catalogues give insight in regional differences and do they say something about the popularity of an instrument, will be discussed.