LINEAR PERSPECTIVE.
Chap. CXII.—Of those who apply themselves to the Practice, without having learnt the Theory of the Art.
Those who become enamoured of the practice of the art, without having previously applied to the diligent study of the scientific part of it, may be compared to mariners, who put to sea in a ship without rudder or compass, and therefore cannot be certain of arriving at the wished-for port.
Practice must always be founded on good theory; to this, Perspective is the guide and entrance, without which nothing can be well done.