Circa il primo modo che si fa con ragione, per essere la cosa in poche parole conclusa da Bramantino in maniera che giudico non potersi dir meglio, contenendovi si tutta Parte del principio al fine, io riferiro per appunto le proprie parole sue (cp.  XXII, Prima prospettiva di Bramantino).  La prima prospettiva fa le cose di punto, e l’altra non mai, e la terza piu appresso.  Adunque la prima si dimanda prospettiva, cioe ragione, la quale fa l’effetto dell’ occhio, facendo crescere e calare secondo gli effetti degli occhi.  Questo crescere e calare non procede della cosa propria, che in se per esser lontana, ovvero vicina, per quello effetto non puo crescere e sminuire, ma procede dagli effetti degli occhi, i quali sono piccioli, e percio volendo vedere tanto gran cosa_, bisogna che mandino fuora la virtu visiva, la quale si dilata in tanta larghezza, che piglia tutto quello che vuoi vedere, ed arrivando a quella cosa la vede dove e:  e da lei agli occhi per quello circuito fino all’ occhio, e tutto quello termine e pieno di quella cosa.

It is worthy of note that Leonardo had made his memorandum refuting this view, at Milan in 1492]

69.

A parallel case.

Just as a stone flung into the water becomes the centre and cause of many circles, and as sound diffuses itself in circles in the air:  so any object, placed in the luminous atmosphere, diffuses itself in circles, and fills the surrounding air with infinite images of itself.  And is repeated, the whole every-where, and the whole in every smallest part.  This can be proved by experiment, since if you shut a window that faces west and make a hole [Footnote:  6.  Here the text breaks off.] . .

[Footnote:  Compare LIBRI, Histoire des sciences mathematiques en Italie.  Tome III, p. 43.]

The function of the eye as explained by the camera obscura (70. 71).

70.

If the object in front of the eye sends its image to the eye, the eye, on the other hand, sends its image to the object, and no portion whatever of the object is lost in the images it throws off, for any reason either in the eye or the object.  Therefore we may rather believe it to be the nature and potency of our luminous atmosphere which absorbs the images of the objects existing in it, than the nature of the objects, to send their images through the air.  If the object opposite to the eye were to send its image to the eye, the eye would have to do the same to the object, whence it might seem that these images were an emanation.  But, if so, it would be necessary [to admit] that every object became rapidly smaller; because each object appears by its images in the surrounding atmosphere.  That is:  the whole object in the whole atmosphere, and in each part; and all the objects in the whole atmosphere and all of them in each part; speaking of that atmosphere which is able to contain in itself the straight and radiating lines of the images projected by the objects.  From this it seems necessary to admit that it is in the nature of the atmosphere, which subsists between the objects, and which attracts the images of things to itself like a loadstone, being placed between them.