If you look at a luminous body in the far distance through a smallhole it will seem to grow less, and if you look at it near at hand it will not undergo any change. That is that if you look at this light atadistance of one or two braccia from the aforesaid hole it will not undergo any change whether you are looking at it through this hole or outside of it.

All bodies together, and each by itself, give off to the surrounding air an infinite number of images which are all-pervading and each complete, each conveying the nature, colour and form of the body which produces it.

Light is the chaser away of darkness. Shade is the obstruction of light. Primary light is that which falls on objects and causes light and shade. And derived lights are those portions of a body which are illuminated by the primary light. A primary shadow is that side of a body on which the light cannot fall.

Every body that moves rapidly seems to colour its path with the impression of its hue. The truth of this proposition is seen from experi-ence; thus when the lightning moves among dark clouds the speedofits sinuous flight makes its whole course resemble a luminous snake.So in like manner if you wave a lighted brand its whole course will seem a ring of flame. This is because the organ of perception acts more rapidly than the judgment.

A single and distinct luminous body causes stronger relief in the objects than a diffused light; as may be seen by comparing one side of a landscape illuminated by the sun, and one overshadowed by clouds, and illuminated only by the diffused light of the atmosphere.

All objects transmit their image to the eye in pyramids and the nearer to the eye these pyramids are intersected the smaller will the image appear of the objects which cause them.