The Fresnel Principle

Each annular ring reduces mass by eighty percent while preserving the focal length that projects light beyond twenty nautical miles.

A central double-convex element gathers scattered rays into a single coherent column, the brightest point in every Fresnel assembly.

Framework spacing accounts for thermal expansion, keeping each prism ring aligned through decades of coastal salt air and vibration.

Clockwork-driven revolution produces distinctive flash patterns — each lighthouse identifiable by its rhythm alone along the darkened coast.