In all the modern textbooks on electromagnetism that I have seen, Maxwell’s equations are introduced in a rather poorly motivated way, in my opinion. It is often left unexplained how one goes from experimental facts to the equations. Sometimes the equations are simply postulated from the very beginning, and only afterward is it shown how they account for the experiments.
As far as I understand, this can be explained by the fact that Maxwell himself derived his equations under the assumption that the electromagnetic field represents a certain mechanical deformation of a hypothetical ether.
The ether theory was mainstream in 19th-century physics; both optics and electromagnetism were based on the assumption of its existence. Predictions of these theories agreed remarkably well with numerous experiments. However, the concept of the ether was abandoned following the Michelson-Morley experiment and the development of special relativity.
My impression is that once the ether was discarded, the original motivation for Maxwell’s equations largely disappeared.
I wonder if there exists a survey of the ether theory that provides a basic understanding of how Maxwell originally obtained his equations.I wonder if there exists a survey of the ether theory that provides a basic understanding of how Maxwell originally obtained his equations.