Circular Building Plan with Rooms, a Device and Sums
A round plan labelled stairs, window, well and chimney, a ring-stand device, and a multiplication
This blue folded sheet gathers several studies: at lower right a circular building plan whose rooms are named with two staircases (one coming from below, one going above), windows, a well and a chimney, and whose orientation to the East is fixed with the sheet reversed. At the left a mechanism carries a ring or circular platform on a vertical stand, annotated with the figures 144, 18, 6 and 36, while a short calculation multiplies 36 by 4 to reach 144. Measurements of 1 1/4 braccia are noted along the central fold. Further mechanical sketches and mirror-script, only partly transcribed, are also present.
On this page
Circular plan: stairs, windows, well and chimney
The round plan at lower right is set out with two staircases, one coming up from below and one going up above, together with windows, a well and a chimney marking the internal rooms. It is captioned simply 'Stairs - Stairs'.
Orientation to the East (Levante)
With the sheet turned upside down, the word 'Levante' (East) is written to fix the compass orientation of the circular plan.
Ring-platform device with figures 144, 18, 6, 36
At the left a mechanism carries a circular ring or platform upon a vertical stand. Beside it Leonardo notes the numbers 144, 18, 6 and 36, apparently gearing or sizing the device.
Multiplication of 36 by 4 giving 144
A short arithmetical operation multiplies 36 by 4 to obtain 144, the same figure that annotates the ring-stand mechanism.