Maxwell studied Ampere's Laws more deeply than any of his contemporaries.

In his discussions of electrodynamics, [Treatise On Electricity and Magnetism] he reminded his readers:

"...It must be carefully remembered, that the mechanical force which urges a conductor carrying a current, across the lines of magnetic force, acts, not on the electric current, but on the conductor which carries it."

(Note: The mechanical force which is observed acting on the conductor is known as the "Ponderomotive Force").

" ...The only force which acts on the electric current is the electromotive force, which must be distinguished from mechanical force."

This clear distinction between ponderomotive force and electromotive force was wrongly obliterated by the introduction of the Lorentz force law, on which the obviously flawed theory of relativistic electromagnetism, was erroneously based.

Why does this matter? The distinction between mechanical forces, such as stress, or acceleration, which act on ponderable matter should never be confused with any of the activities of the so-called "fields".       Confusion results in delusion.

Again, quoting Maxwell, "...Electromotive force is always to be understood to act on electricity only, not on the bodies in which the electricity resides. It is never to be confounded with ordinary mechanical force, which acts on bodies only, not on the electricity between them."

Ampere primarily studied ponderomotive [mechanical] interactions of current-carrying objects. Ampere himself said, "...Newton taught us that motion of this kind, like all motions in nature, must be reducible by calculation, to forces acting between two material particles, along the straight line between them, such that, the action of one upon the other is equal and opposite to that which the latter has on the former, and consequently, assuming the two particles to be permanently associated [rigidly linked] so that no motion whatsoever will result from their mutual interaction." (This is just Newton's third law applied to the situations which result in ponderomotive forces.)]

Directly quoting Newton, his third law reads: "To every action there is always opposed an equal reaction: or the mutual actions of the two bodies are always equal and directed to contrary parts."

Newton's law is applicable to situations which involve two, and only two, material entities. It does not apply to interactions between the material body and some "field", such as the electromotive forces, which are NON-RECIPROCAL in behavior. Further, according to the above, neither material entity acts exclusively on itself.

Fundamentally, Ampere's law predicts a longitudinal force will exist along the path of a material conductor, due to the activities of Newton's third law on the material (atomic lattices) which comprises the conductor. In these studies, there is no linkage whatsoever between the "electric fluid" and the conductor material. In our present day knowledge of such systems, any mechanical forces which may arise due to collisions between electron transports and lattice ions are entirely negligible, relative to the amount of heat released by such events, and due to the miniscule mass of the electron, relative to the atomic lattice structures. Fundamentally, Ampere's law describes the responses of the atomic lattices which comprise the conductor, to the application of an electrical current I , such that the magnetic force H which is exerted on a unit magnetic pole is inversely proportional to the shortest distance, r, to the wire. This is known as the Biot-Savart law, and is written as,

H = k I/r,

where k is a dimensional constant.