THE BATH.
To heat the water for the stove of the Duchess take four parts of cold water to three parts of hot water.
[Footnote: Duchessa di Milano, Beatrice d’Este, wife of Ludovico il Moro to whom she was married, in 1491. She died in June 1497.]
Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.