Diffraction of Light
[The following picture gives only a rough, qualitative view]
As Mayo mentions, Worall (1989) examines historical evidence for the effects of Fresnel's theory of diffraction. But what's diffraction, in the first place? It is an optical phenomenon; light seems to go into the "shadow", and shadow appears where you may not expect it. Here are a few typical examples, the first of which is "legendary". Poisson (one of the members of the Commision for examining Fresnel's paper) is said to have converted to the wave theory by seeing this singular result, which he deduced from Fresnel's theory and took as a conclusive counterevidence against Fresnel's theory. Worall complains that it is very hard to find historical evidence for such a dramatic conversion on the part of Poisson.
But Worall's philosophical argument based on this example is not very impressive, as Mayo points out.
Reference
Worall, John (1989) "Fresnel, Poisson and the White Spot: the role of successful predictions in the acceptance of scientific theories", in The Uses of Experiment (ed. by D. Gooding, T. Pinch, and S. Schaffer), Cambridge University Press, 1989.
Last modified Jan. 27, 2003. (c) Soshichi Uchii
