Nice project! This video: https://www.youtube.com/watch?v=5nBY4Y0bicM explains why the original interferometer was designed in the first place: to detect a hypothetical luminiferous ether, before Relativity theory made it unnecessary.

It's important to say the original interferometer was much less elegant -- there were no lasers in 1887. But it did have a solid stone "boat" floating in a little lake of mercury. Not making this up.