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was arrived at independently by Joseph Larmor and published in 1900.

All the above equations are familiar to anyone conversant with special relativity, but there is still a huge conceptual leap to be made before we arrive at Einstein's formulation of the theory. Lorentz, FitzGerald, and others were trying to construct a system in which electromagnetic phenomena could be made consistent with a stationary ether, and the transformations they introduced were intended to represent some dynamical process.

More remarkable than the work described above were the contributions of Poincare. In La mesure du temps (1898), he discussed the problems inherent in the way time is measured, and came to the conclusion that the concept of simultaneity could not be defined objectively. In an address to the International Congress of Arts and Science in 1904, he went further and discussed the synchronization of clocks via light signals by two observers moving relative to one another, describing how the Lorentz transformations lead to the concept of time dilation. Poincare was still embedded firmly in nineteenth-century dynamics, but he could see the possibility that something new might be around the corner. He was remarkably prescient about the form such a new dynamics might take:

Perhaps, too, we shall have to construct an entirely new mechanics that we only succeed in catching a glimpse of, where, inertia increasing with velocity, the velocity of light would become an impassable limit. The ordinary mechanics, more simple, would remain a first approximation, since it would be true for velocities not too great, so that the old dynamics would still be found under the new. ... I hasten to say in conclusion that we are not yet there, and as yet nothing proves that the

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