In his first 1905 article on special relativity, clock synchronization by means of light rays was used by Einstein to derive the Lorentz transformations ( Ann. Phys., Lpz. 322 891–921). However, the same goal can be achieved by using bodies in free motion to synchronize clocks. To this end, one has to accept the principle of relativity, the law of inertia and the existence of a limit value for the speed of massive bodies with no appeal to electromagnetic phenomena until the very last step of the derivation, when the limit speed must be identified with that of light in vacuum. (In the absence of this speed limit one recovers the Galilean transformations.)

中文翻译：

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惯性定律，时钟同步，速度限制和洛伦兹变换

在爱因斯坦1905年关于狭义相对论的第一篇文章中，爱因斯坦利用光线的时钟同步来推导洛伦兹变换（Ann。Phys。，Lpz。322 891–921）。但是，通过使用自由运动的主体来同步时钟，可以实现相同的目标。为此，必须接受相对性原理，惯性定律和存在的质量极限值，在推导的最后一步之前，对电磁现象没有吸引力，直到推导的最后一步为止被真空中的光识别。（在没有此速度限制的情况下，将恢复伽利略转换。）