“Method for seeing when the weather goes bad.”
The model is constituted of a wooden
supporting structure on which the triangular
supporting arms of a balance are attached. A plumb line hangs from the top of the balance to indicate the measure on a graduated scale. In the two balance pans there are two materials: one is impermeable (the wax), while the other is hygroscopic (absorbent: the sponge or cotton) and weighs more in accordance as the air is more humid, causing the balance pans to incline.
The model is based on the drawing:
- Codex Atlanticus f. 30 v. (1487)
Milano, Biblioteca Ambrosiana