Historically magnets came first to excite our attention, while electric charge was a curiosity, which was explained by Thales as magnetism. But of course, nothing was that clear. It was the Cinese that patiently discovered the dipole which they caller a lodestone needle. The Indians had great deposits of magnetite, but benefitted from Chinese research into navigating using the lodestone needle.
Some early research was done in the west which deepened the mystery as it showed heat affected magnetism. In the to growmeantime electric charge was not advanced much beyond Thales conception of a material requiring friction to be "magnetised"
The magnet, especially the dipole or needle magnet was studied more closely as a more scientific empirical approach gained favour, and magnetism through the dipole lead to the theory of the earth being a large magnetic dipole.
Once that was put forward research into magnetism waned, but research into electric charge began, principally because Gilbert overturned Thales description by careful research and experimentation, showing a different natural force was involved. Thus research into electricity started in earnest and the model of magnetism was used tu frame the new discoveries..
Gilbert had distinguished magnetism from electric attractive forces simply by the fact that there were Two kinds of electric attraction which existed in different materials, whereas magnetism always existed in the same material as one system with 2 poles. It soon became clear that the two poles of the magnet were analogous to the two electric attractive forces, nd the repulsions were the same, thus it was possible to arrange the electric charges in a similar dipole system to a Manet. So the electric dipole was created, but again not understood.
However electricity had a property lodestone did not, it cold accumulate to very high forces on a material that "carried" it, and then it could discharge in a spark of lightening! The charge could then be built up again. Secondly, the dipole was not in a rigid configuration, and in fact it would lead to mutual attraction and discharge, something that never happened to a magnet. A maf
Gent could only be destroyed by heat..
It was Orrsted who found that a charge could be discharged safely through a wire over a longer period of time. This he called a current. He then noted that a current in a wire affected a magnetic dipole needle, and the electro magnetic link was made via the magnetic dipole movement now called a moment. Because the current was flowing from one pole of an electric dipole to another, it was clear that the electric dipole was somehow producing a magnetic dipole, that is a lodestone magnet. This was experimentally investigated to be a cylindrical effect around the wire, but attracting the magnetic dipole one way or the other depending on current direction. However,mif a loop of wire was made then the loop naturally had two discernible orientations and the lodestone dipole clearly indicated which side was which. The added factor was that by switching the current flow direction only, the lodestone dipole detected that change as a reversal of poles.
What it was possible to show was that the magnetic effects in a solenoid loop were identical to the magnetic effects around a lodestone dipole. This was made clear by intensifying the lodestone dipole to the size of a bar magnet.
Now it was anticipated that the same force behaviours would exist for an electric dipole, but it took some time to identify a suitable detector. So it was found by Faraday , and others that an analogy existed between charge dipoles and magnetic dipoles. Figuring out the relationships lead Maxwell to the electromagnetic equations AS a description of empirical data. In the meantime Coulomb recognised an inverse square law on an analogy with gravity, and used the charge dipole as his test dipole, so the force was measured by the est dipole as a proportional relationship to the test dipole. In a similar way, Newton used quantity of matter as the test for gravity, but because of mutuality he had to use both quantities of matter.
Now Galileo demonstrated that there was no dipole moment in the gravitational field by dropping two different masses together. They bot hi the ground at the same time, when people generally expected the heavier to fall faster.. Nevertheless the two masses in the gravitational equation did rotate about a centre of symmetry under their own attractive dynamics, and when we look at the behaviour of 3 or more charges we find the same results that Galileo found, charges in the same field behave the same way.
The lodestone dipole and the charge dipole are the same, but the gravity field is no brcause it behaves like a composite field, not a fundamental field. A fundamental field is distinguished by its behaviour on its test dipoles.
The notion of a dipole is introduced in electrostatics, which is misleading. The current definitions still use the notion of a point charge, and this sets up a smokescreen to clear thinking. The dipole actually arises in magnetism, where it is a natural structural feature of magnets, and where it is clear that no monopole exists for magnetism, a distinction Gilbert made. What was not clear until electrostatics was developed was the electrostatic charge structure of a magnet. Simply put a magnetic dipole exists only when a charge structure exists between the apparent poles of the magnet. The charge structure is due to the dynamic motion of charge, and this is apparently perpendicular to the magnetic pole alignment.
Now this is of course only apparently perpendicular. Electrostatics allows us to establish charge centres spherically radia
L to any other charge centre. Although we posit a point charge, no one has ever empirically seen or measured one . However we have experienced and measured charge densities, and this is an entirely different phenomenon. Charge densities have enabled us to map charge distributions around them and from that to deduce the inverse square law. It was a observation sent to coulomb about charge in side a charged container, which was that there appeared to be none, that alerted him to the similarity to a gravitational anomaly he knew of. A sheet of gravitational material exerts no gravity on its interior if it is formed into a spherical shell. Thus a charge sheet it was apparent was doing the same. This was highly suggestive of an inverse square law.
Beyond this tentative observation there was no other real explanation accounting for all the observed behaviours, and so this formulation has stuck.
These relations can be derived from Maxwells equations, and also from Einsteins field equations, but of course that is to be expected, as generalisations of the basic experimental data. The Lagrangian mechanics is at the heart of these apparent differences, and so it should not be naively assumed that any new discoveries are at the core of this. This is simply the consequence of doing mechanics the Lagrangian way. You get a lot more out because you have to put a heck of a lot more in!
So the point is, that no one was able to see that a step back was needed to redefine matter and thus quantity of matter. Instead charge was invented and loaded onto matter. This was unusual, because Boyle spoke of fluids that entered INTO matter in some way, but as I have explained, the charge of occultism was a serious charge, akin to be declared a witch or a warlock! Thus nobody wanted to pursue that line of thought, and indeed Gilbert did not and he was the foremost authority at the time on magnetism and electric fluids.
Magnetism was an inherent part of iron it was thought, but electric fluids were deposited on matter by rubbing! This has never fundamentally changed. Even today, with the discovery of some exotic boson, charge is still carried by the matter, not inherent within it. Of corse magnetism had to change its status, but that was all that experimenters thought they had to do. The reason is obvious to me, and that is that mass had been given an unassailable status as the essential building block of matter. What was matter if it was not mass?
It took time to loosen the grip of this notion on matter, and that only really started to happen when Einsteins rest mass energy appeared to be verified by nuclear annihilation. Mass could be converted into any other form of work, and thus any other form of energy.
Was mass just energy then?
We jump from one illdefined concept to another even more esoteric one, it seems. For a long time scientists debated whether matter was a wave or a particle, specifically whether light was a wave or a particle, but the whole zoo of particles was dependent on that decision. In the end they fudged it.
Few realise that Einstein envisaged the electron as the fundamental particle, only calling it the photon to satisfy the then experimental data on light. The name stuck, and of course there has never yet been any evidence to support the notion of a super light electron. An entirely new particle had to be defined. But this particle had no mass! How could it even exist! Thus the debate about the wave particle distinction particularly focused on light.
Matter was literally about to disintegrate before physicists eyes, and the only thing they had to cling on to was mass. Now most modern physicists are aunfait with Energy, and this really is the "new black" as the saying goes. They still like to talk in terms of particles though, because it is hard to differentiate otherwise.
There is a move to differentiate through the probability distribution of the Psi wave function, but that is so special, only a few can think in those terms.
We could have made the change at the time Coulomb put forward his law for charge. The quantity of matter, which the German philosophers called Masse, should have been changed to the quantity of charge. By this I mean that mass would be replaced by the concept of charge, that matter would consist of particles of charge. It would then have been easy to understand what has come to be called energy is the attribute of charge. Matter would then consist of two different kinds of charge and we could then precede to explain classical mechanics in these terms. This of course would have had great difficulties in explaining magnetism and electric charge until electric current was discovered , but it would have been possible to give a full accounting of experimental data once the lodestone dipole was understood.
The lodestone dipole is simply the effect of curving a cylindrical field on itself. And the cylindrical field is simply the effect of moving a spherical field in a linear direction. This Trochoidal field has polar direction due to the spherical fields intersecting and defining the field lines called flux lines by intersection of spheres. These flux lines are further compounded by the spin of the charges in motion. None of this would have been discoverable without the observation of current flow, and current flow is the motion of charge density along the dipole field lines. However those dipole field lines in a conductor easily extend along the conductor to the different charge types! The flow is rapid but wave like because it is not a particle of charge flowing along the conductor to the opposite charge, it is the charge density flowing into the conductor as the charge is "sucked" out of the other end! The transmission is therefore potentially instantaneous, except that in the real "fluid" situation there is an elasticity which means a compression wave is actually established in the conductor. This compression wave speed actually determines the speed of the flow, and consequently flow is limited to the speed of light in a material.
Other factors also show up like temperature change which interferes with the compression wave, and also the effects of the opposite charge particles in the conductor.
The creation of the dynamic electric field also has reaction consequences and interactions with charges outside of the conductor, but the biggest effect comes when the electric field cylinder is curved on itself. Then magnetic(dynamic electric fied) effects create self interactions and multiple dynamic dipole configurations. This status results in the dynamic magnetic behaviours observed.
Permanent magnets were finally explained when charge spin was acknowledged and current domains identified. The rest is due to the self organising behaviour of both electric and magnetic dipoles.
Particles of charge are where we should have attained to with classical physics, having ditched the notion of mass.