In praise of the sun; and Book 10 on reservoir outlets
The sun as the universe's greatest body and source of light and life, opened by a chapter-heading on water reservoirs
A heading announces 'Book 10,' a treatise on the varying depths and rounded forms inside reservoirs before the water's outlets, with spiracles of different heights, widths and wall-thicknesses. The main text is a hymn to the sun: Leonardo marvels that Socrates likened it to a burning stone and wishes he had words to blame those who would rather adore men than this body, the greatest in magnitude and virtue in the universe. Its light illuminates every celestial body, and, he argues, all souls and animal heat descend from it, so those who worshipped men such as Jove, Saturn and Mars as gods erred greatly. A marginal note adds that La Spera and Marullo, among many others, praise the sun.
On this page
The sun, greatest body of the universe
Leonardo defends the sun against Socrates, who likened it to a burning stone, and rebukes those who adore men rather than this body, which he holds to be of the greatest magnitude and virtue in the universe. Its light illuminates all the celestial bodies, and he claims that souls and the heat of living animals descend from it, promising fuller proof in his fourth book. Those who worshipped men as gods erred, since even a man as great as the world would seem a mere point among the stars.
Book 10: depths and spiracles of water reservoirs
The chapter-heading sets out a study of the various depths and rounded hollows inside reservoirs, placed before the outlets where water escapes with differing velocities, sizes, depths and widths. The spiracles themselves vary — high or low, wide or narrow, thick-walled or thin.
Poets who praise the sun (margin)
A note in the margin records that La Spera and Marullo, together with many others, praise this sun, aligning Leonardo's own encomium with a literary tradition.