The aim of the earlier thinkers, to reduce the whole of electrical science to one equation was now to be realized in a way that marks one of the most important epochs in the history of physical science; an epoch comparable only to that of Newton...
Maxwell's best friends were apprehensive, since the theory predicted even more than was believed to exist, until in 1877 the new Maxwellian light dawned upon the mind of Hertz. The theory endowed the world medium, the ether with new potencies, in insisting on its continuity, on the point to point transfer of electric force, so that ether stress became one of its familiar images, a veritable charm to conjure by.
Hydrodynamics... profited and such beautiful researches as those of the Bjerknes (1863 et. seq.) father and son, were stimulated in proportion as they fitted into the electromagnetic scheme.
It was inevitable... that in the further treatment of Maxwell's equation the use of vector methods of computation should become indispensable in physics.
The ether electrically ignored heretofore has become all embracing. Woe to him that lisps, action at a distance!
Maxwell's theory, which according to Hertz means Maxwell's equations, thus includes the whole of physics, dynamics alone excepted, and the world equation has advanced another step.
Maxwell indeed, following the established custom, endeavored to call dynamics to his aid; but... mechanics had no counsel to give.
Naturally the theory so revolutionary gained headway but slowly... unfortunately Kelvin, and (I believe) Rayleigh long remained unconvinced.
The troubles begin with the study of the first-order effects of moving optical systems, in the researches of Fizeau (1851); they become grave in the famous experiment of Michelson (1881) where the effects to be observed are of the second order.
The speed of the earth, regarded optically from axes fixed in the ether, is zero. The ether and the earth have no relative velocity. This is tantamount to a rejection of the ether. Judge the consternation!
As Maxwell's equation contained no direct reference to the motion of the charged body, a first attempt... was made by Hertz (1890) to supply this deficiency; but it was not of permanent value.
The peculiar feature of the ether, its permittance and permeability, were abolished and in their place appears the velocity and density of the electron, or charged particle. Electric fluid exists; magnetic fluid does not.
Lorentz then showed with consummate skill that the equations of the classic electromagnetics of Maxwell could be retained, that both the scaler potential and the vector-potential would retain their original form, would be invariant, so to speak, if the time-variable were belated by the interval consumed by light in passing from the source to the point of application in question.
The new bodies, showing an inertia or virtual mass depending in a pronounced way on their speed, made havoc with Newton's laws and swept the classic dynamics mercilessly out of the field, as an arbiter of world phenomena.
Theories such as those of Lorentz, 1892, or of Larmor, 1894, were now the only refuge. What could they do, was the ardent question, to replace dynamics?
Following the suggestion of Lorentz that the moving system contracts in the direction of motion, or at least apparently contracts to the fixed witness, Einstein in 1905 was the first to clearly perceive the iron logic of the situation; and the logic of a desperate situation is all there is in the theory of relativity.
The equations of this celebrated , culminating in Einstein's famous addition theorem of velocities belonging to different systems—an ultimate break with the , where time has the same absolute value everywhere—have been the very focus of discussion for the last ten years.
In its original form, the principle is as yet rather a detached statement, adapted to definite purposes but lacking in mathematical elegance. It was left to the genius of Minkowski (1908) to mould this flotsam of ideas into a philosophical system of extraordinary symmetry and breadth, the promise of which it is as yet too soon to adequately appreciate.
Gravity still acts at a distance, as did the electrical vector in the days of Weber. Nor is the most generalized electromagnetic field able to account for the spectrum distribution of radiation, in the development of which energy threatens to pursue, if it has not already entered, the route of atomistic physics occupied by chemistry.
Of the Planck molecular oscillators... If operating continuously under the established electromagnetic laws they lead to the impossible distributions of energy in the spectrum investigated by Rayleigh and Jeans. But if emitting only, when their energy content is a whole number of energy elements, a case thus involving the entropy probability of Boltzmann, Wien's law and the numerical data referred to are deducible with astounding precision.