Those who are in love with practice without knowledge are like the sailor who gets into a ship without rudder or compass and who never can be certain whether he is going
Hence, as a general rule, Nature teaches us that an object can never be seen perfectly unless the space between it and the eye is equal, at least, to the length of
he 3 branches of Perspective, which are: the diminution in the distinctness of the forms of the objects; the diminution in their magnitude; and the diminution in their colour.