Epistemic Artifacts: Michael Faraday’s Search for the Optical Effects of Gold

Abstract

In 1856, Michael Faraday (1791-1867) carried out an extensive program of research to explore the properties of thin films of metallic gold. Such films had long been of interest to him because they possess the peculiar property of appearing gold in color by reflected light, but green by transmitted light. Faraday hoped this behavior would model the general interaction of light and matter, perhaps extending his earlier finding that magnetic fields could affect a beam of polarized light passing through a highly refractive substance. In the course of this work, Faraday prepared over 600 microscope slides with thin metallic films adhering to them. Most of these epistemic artifacts have survived, as have his extensive diary records. Examination of this material permits reconstruction of his successive attempts to create a kind of dialogue with nature and provides evidence for his sophisticated ability to interactively create a microverse that could expand his mental microverse of field lines of force. While he failed to achieve his larger goals, the surviving specimens constitute a series of increasingly articulated representations of the structure of metallic matter. The case is thus one in which the “model” converges with the very thing intended to be modelled.