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arXiv · 2510.19833

Fresnel's Mechanical Legacy Recovered: The Drag Coefficient from Carried Compliance, and the Two Laws Bubble Acoustics Separates

Abstract

Fresnel derived the drag coefficient of moving transparent matter from a mechanical argument in 1818, and a century of interferometry confirmed it exactly as he gave it. We show that the mechanical underpinning he sought was workable in principle and wrong in one word: density, where the mechanics says compliance. The complete first-order coefficient follows from a single constitutive calculation, each component responding along its own path at the frequency it samples: $$f(ω) = C_{\rm soft}/C_{\rm total} + (ω/2)\,C_{\rm soft}'(ω)/C_{\rm total}.$$ The coefficient contains two laws. The first is the law Fresnel wrote: the non-dispersive part, $1-1/n^2$, equals the modified medium's share of the wave-accessible compliance, $χ/(1+χ)$: his excess hypothesis made exact. The second is a law of resonance, the term Lorentz derived and Zeeman confirmed. We prove the resonance law is universal mechanics: sound in a bubbly liquid obeys it in the same form and prefactor, eleven orders of magnitude below, invariantly across the analyzed two-fluid closures. The same analysis shows the share law is the carried-response term: present when the compliant channel stores and delivers in its moving frame, absent from every closure that severs response from carrier. Closure-bound cavities (geometry fixed by phase closure of the medium's waves) provide that custody by construction. One transport structure thus appears three times: light in moving glass carries both terms, the drifting bubbly liquid isolates the resonance term by slipping, and Lorentzian velocity composition reproduces the share. The direction of derivation is established: the mechanics generates what the kinematics reproduces; the composition is itself derived as the cavities' closure condition in a companion paper (arXiv:2604.27525). A documentary history traces how interpretation fused the two laws, Fresnel to Zeeman.

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Shiva Meucci. 2026-08-23. Fresnel's Mechanical Legacy Recovered: The Drag Coefficient from Carried Compliance, and the Two Laws Bubble Acoustics Separates. https://arxiv.org/abs/2510.19833

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