In the Introduction the several branches of Physics are classified according to the sensory experience whereby the coincidence is recorded, thereby orienting the term “visual coincidence.” The rôle of the clock mechanism in dynamical formulation is briefly discussed. In Part I, an array of Michelson rotating mirror clocks, giving a postulated light-velocity effect, is used as a background for an empirical criterion for the synchronization of clocks. In Part II, the empirical criterion for synchronization in question is formulated in such a way as to disclose the existence of an absolute kinematic quantum, capable of macroscopic test, contingent on the light-velocity effect postulated in Part I. In Part III, the galilean spacetime scale is introduced as a kinematic “crystal” lattice whose gauge is the absolute kinematic quantum discussed in Part II. The question is raised whether in problems involving the ordering of sharp steady light images concentrated in lines or points, the images themselves may not form a three coördinate galilean or non-galilean spacetime lattice of synchronized clock-points, and are not more immediately described this way than by reference to the amorphous galilean or non-galilean four-coördinate reference systems. It is suggested that the quantum problem insofar as it treats of spectroscopic and crystallographic electromagnetic image patterns may be treated through an establishment of transformation equations between observed coincidences of a spacetime scale, as such, and the same observed coincidences referred to a uniform length scale.