The pupil in sudden light; ball rebound; light through apertures

An eye used to darkness is harmed by sudden light

The eye accustomed to darkness has a widely opened pupil; when light suddenly enters, too much of the darkened eye is harmed by its contrary, and the pupil abruptly contracts to a tiny circle, a sudden movement not without rubbing on the eye's sensitive parts. Leonardo proposes to prove it by letting the sun fall on only one eye of a nocturnal animal and comparing the two pupils.

All motions rebound at equal angles; the spinning ball

Leonardo states that all bodily and spiritual motions, after percussion, rebound between equal angles. Three figures of a rebounding ball follow: striking b, the part a wants to fall, whence the ball rises turning, that is, it spins as it bounces.

Light through a small aperture projects inverted (the candle)

The sun and every luminous body that sends its rays through an aperture smaller than itself will project them inverted beyond that aperture. Leonardo says the effect can be seen with a lit candle, taking its rays beyond a hole smaller than itself; the figure shows the candle and its upside-down image.

Sun in a transparent sphere: reflection and rainbow (b d a - c f e)

In a spherical, transparent ball the sun a appears on the convex top at d and inverted in the hollow at b, is reflected at c, and is seen at f, all to an eye placed at e. Between c and b there forms a circle ringed by a rainbow.

A lamp reflected in four places on the sphere (b f - c a d - e)

If the light is placed at f it rebounds to the eye in four places: on the convex top at d, in the hollow upside down at c, thence straight to b, and from b straight again to a. A neighbouring figure repeats the scheme for a light at a seen by an eye at b, reflecting to e and f opposite.

How things turn upside down (a b t r n)

A left-column figure notes that a b will appear at n as wide as r t, and another that the light appears on the convex top at a and in the hollow at b. A small figure at the foot is captioned simply on how things turn upside down.

Colonna destra:

Tre figure di palla rimbalzante, l'ultima con:

Figura di candela accesa e sua immagine capovolta:

Colonna sinistra. Figura colle lettere:

Figura colle lettere:

Figura colle lettere:

Figura con:

A destra della precedente, figura colte lettere:

Figura sotto la precedente:

Right column:

Three figures of a rebounding ball, the last with:

Figure of a lit candle and its inverted image:

Left column. Figure with letters:

Figure with letters:

Figure with letters:

Figure with:

To the right of the preceding, figure with letters:

Figure below the preceding: