A Classical Hydrodynamic Paradigm: The Classical Tests of Gravitation in Flat Euclidean Space

This paper assembles the classical tests of gravitation within a single flat-space treatment, using ordinary vector calculus in three-dimensional Euclidean space with a universal time parameter and no tensor apparatus at any step. Its principal structural result concerns a feature earlier formulations in this series adopted as a postulate and which is here shown to be forced by observation. Gravitational light deflection requires a spatial response coefficient of two, while gravitational clock rates require a temporal coefficient of one, and the measured ratio between them is exactly two. No medium characterized by a single scalar property can satisfy both measurements simultaneously: setting the common coefficient to two doubles the predicted redshift and contradicts the Pound-Rebka measurement, while setting it to one halves the predicted deflection to 0.8758 arcseconds, the value refuted by the 1919 eclipse observations. Two independent response functions are therefore a theorem about the data rather than an assumption of this framework, and general relativity's own metric likewise carries two independent functions in the static spherically symmetric case. With that structure established, the paper obtains five classical results: solar light deflection of 1.7516 arcseconds, Mercury's perihelion advance of 42.992 arcseconds per century via the Binet substitution, gravitational redshift of 2.459 times ten to the minus fifteen for the Pound-Rebka geometry, a Shapiro round-trip delay of 232.6 microseconds, and the frame-dragging dipole. Each is identified as dependent on or independent of the framework's calibrated constants, and three of the five are independent. The paper closes with a reinterpretation of black holes as objects of extreme refraction rather than true causal horizons, and states the three specific observational results, photon-ring geometry, ringdown spectra, and the absence of a thermal surface signature, that this hypothesis would need to reproduce and does not.