Da Vinci Notes #56 - Go There to See the Truth

There are only bases without pyramids which constantly diminish up

to this point. And from the first base where the vertical plane is

placed towards the point in the eye there will be only pyramids

without bases; as shown in the example given above.

Now, let _a b_be the said vertical plane and _r_ the point of the pyramid

terminating in the eye, and _n_ the point of diminution which is

always in a straight line opposite the eye and always moves as the

eye moves--just as when a rod is moved its shadow moves, and moves

with it, precisely as the shadow moves with a body. And each point

is the apex of a pyramid, all having a common base with the

intervening vertical plane. But although their bases are equal their

angles are not equal, because the diminishing point is the

termination of a smaller angle than that of the eye. If you ask me:

"By what practical experience can you show me these points?" I

reply--so far as concerns the diminishing point which moves with you

--when you walk by a ploughed field look at the straight furrows

which come down with their ends to the path where you are walking,

and you will see that each pair of furrows will look as though they