The Palace of the prince must have a piazza in front of it.
Houses intended for dancing or any kind of jumping or any other movements with a multitude of people, must be on the ground- floor; for I have already witnessed the destruction of some, causing death to many persons, and above all let every wall, be it ever so thin, rest on the ground or on arches with a good foundation.
Let the mezzanines of the dwellings be divided by walls made of very thin bricks, and without wood on account of fire.
Let all the privies have ventilation [by shafts] in the thickness of the walls, so as to exhale by the roofs.
The mezzanines should be vaulted, and the vaults will be stronger in proportion as they are of small size.
The ties of oak must be enclosed in the walls in order to be protected from fire.
[Footnote: The remarks accompanying the plan reproduced on Pl. LXXXI, No. 2 are as follows: Above, to the left: “in a angholo stia la guardia de la sstalla” (in the angle a may be the keeper of the stable). Below are the words “strada dabosa” (road to Amboise), parallel with this “fossa br 40” (the moat 40 braccia) fixing the width of the moat. In the large court surrounded by a portico “in terre No.—Largha br.80 e lugha br 120.” To the right of the castle is a large basin for aquatic sports with the words “Giostre colle nave cioe li giostra li stieno sopra le na” (Jousting in boats that is the men are to be in boats). J. P. R.]
The privies must be numerous and going one into the other in order that the stench may not penetrate into the dwellings., and all their doors must shut off themselves with counterpoises.
The main division of the facade of this palace is into two portions; that is to say the width of the court-yard must be half the whole facade; the 2nd ...
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.