The idea of ether or something like it, had been around since the time of the ancient Greeks. By the last decades of the 19th century, and in line with Newtonian physics, the ether was postulated as an invisible, tasteless, odorless substance that pervaded all unoccupied space, and served as the medium for the passage of electromagnetic waves of light and other kinds of radiant energy, like heat — just as the earth itself serve as the medium for the transmission of seismic waves, for instance.
Late in the last century some very ingenious experiments failed to scientifically prove the existence of the ether, however, and the theory was finally dispensed with for good following Albert Einstein’s publication of his special theory of relativity in 1905.
I think the idea of the ether is an excellent example of how man and woman has always attempted to posit or visualize in physical reality his or her innate knowledge of “Framed-mind 2,”– the unknown.