Filippo Brunelleschi's double-shelled octagonal dome stands as the capstone of Renaissance alchemy (Vas Hermetis, the Hermetic Vessel).
The Octagonal Proportions. The number 8 symbolizes the transition between Earth's square and Heaven's circle.
Verrocchio's Golden Copper Ball. Capping the lantern at 114 meters, this gilded sphere acts as a celestial reflector and lightning rod, catching early morning solar rays.
Paolo dal Pozzo Toscanelli's Solstitial Gnomon. In 1475, astronomer Toscanelli placed a brass aperture plate 90 meters high in the north transept dome. On the Summer Solstice, a solar beam falls onto a marble circular floor plaque to calculate Earth's axial tilt.
Each carries its full hermetic decipherment and an observational protocol — where to stand, when, and what to watch for — in the Florence field codex.