The Brass Floor Strip. Inlaid across the marble transept floor is a narrow brass strip running south to north, terminating at a 10-meter white marble obelisk.
The South Transept Lens Aperture. Installed in 1743 by royal astronomer Pierre-Charles Le Monnier, a glass lens in the south window projects a solar beam onto the brass line at local solar noon to calculate equinox drift and Easter dates.
The Rose Line. Esoteric tradition conflates this strip with the pre-Greenwich Paris Meridian — which in strict truth passes a hundred meters east, through the Observatory. Call the gnomon line the meridian's devotional twin: a celestial spine connecting the church floor to the solar obelisk.
Each carries its full hermetic decipherment and an observational protocol — where to stand, when, and what to watch for — in the Paris field codex.
Or read the complete Florence codex free first.