The Luminiferous Aether? I’m not too sure how mysterious it was, but it persisted a fair while before being squelched by the march of science.
http://en.wikipedia.org/wiki/Timeline_of_luminiferous_aether
The Luminiferous Aether? I’m not too sure how mysterious it was, but it persisted a fair while before being squelched by the march of science.
http://en.wikipedia.org/wiki/Timeline_of_luminiferous_aether