There was nothing left to do but award the prize to Fresnel. Poisson had put forward a consequence of light as a wave that was so ridiculous, so unlikely, that it couldn’t be explained by anything else. Fresnel was smart enough to come up with the theory. Poisson was smart enough to have proved Fresnel right, and proved himself wrong. Even though Dominique Arago had actually done the test, the tiny dot of light at the center of the shadow of a spherical object has ever after been called Poisson’s Spot. There is no perpetual motion in physics, but there is perpetual taunting.
If you want a short story about the essence of science, here it is. You have a model, it makes a testable prediction which will either confirm or falsify it. You do the experiment, find out that the model was right, and then tweak a detractor’s nose in perpetuity.