Maxwell's ideas made a very pretty theory, but this is not enough. Before accepting his ideas of the displacement current and the ether, we insist on experimental verification. During a period of about 50 years after the publication of Maxwell's theory, there were extensive efforts made to verify that changing electric fields did, in fact, produce magnetic fields in the way Maxwell predicted. Maxwell's theory passed every one of these tests with flying colors. But when experiments were performed to try to study the other properties of the ether, there were difficulties. Every experiment to detect the ether in some way other than by observing the magnetic fields produced by its current was a failure. Finally physicists were forced to the following frustrating conclusion: Maxwell's displacement current term is correct and belongs in the equations of electromagnetism; but the ether idea, on which its discovery was based, is incorrect. This is not very satisfying, but we will soon encounter a similar situation when we study Faraday's law, which is the flip side of the displacement current: a changing magnetic field makes an electric field. There is no simple picture, like that of the displacement current in the ether, to explain this effect. Faraday discovered it experimentally, and we accept it. In the same way, we now accept Maxwell's displacement current term in Ampere's law without believing that it represents any sort of real current in the ether.