Gravitation is not a force but the curvature of spacetime near masses. We extend the same reading downward: the binding of atoms and molecules, and beneath it the weak interaction, are read as curvature — not of the metric scale but of the quaternion phase, the i in W = iτ that this series placed at the foundation of spacetime. The framework stays strictly quaternionic; no octonions are invoked until the nucleon door at 1474 MeV. A ladder of visibility thresholds organizes the paper: 23.4 keV opens the atom, 1.022 MeV opens pair creation, 1474 MeV opens the nucleon, and 80.4 GeV resolves the weak bubble, below which the weak interaction masquerades as a zero-range contact force. The Unruh temperature of atomic-binding curvature is 367 K — chemistry runs at the temperature of its own curvature — and weak-scale curvature gives 1.5×10¹⁴ K, within an order of magnitude of the electroweak transition, across fourteen orders of magnitude.