Swan Tower

There's also the famous Michelson-Morley experiment which was done right around that time, which was an attempt to measure the properties of the luminiferous ether, the supposed medium in space in which light propagated. The famous experiment itself wasn't done til 1887, but a precursor was done in '81, and the idea shows that 'we can use things we can measure to measure something not visible or tangible, but that we suspect is there' was alive and well.