Fear arises sooner than anything else.

The Book of the science of Mechanics must precede the Book of useful inventions.

The Bactrian have two humps; the Arabian one only. They are swift in battle and most useful to carry burdens. This animal is extremely observant of rule and measure, for it will not move if it has a greater weight than it is used to, and if it is taken too far it does the same, and suddenly stops and so the merchants are obliged to lodge there.

Men of lofty genius when they are doing the least work are most active.

The painter who draws by practise and judgment of the eye without the use of reason is like the mirror which reproduces within itself all the objects which are set opposite to it without knowledge of the same.

Poor is the pupil who does not surpass his master.

Let the painter composing narrative pictures take pleasure in wealth and variety, and avoid repeating any part that occurs in it, so that the uniqueness and abundance attract people to it and delight the eye of the observer. I say that a narrative painting requires (depending on the scene), wherever the eye falls, a mixture of men of diverse appearances, of diverse ages and dress, combined together with women, children, dogs, horses, buildings, fields, and hills.