Chap. CX.—Of mental Motions.
A mere thought, or operation of the mind, excites only simple and easy motions of the body; not this way, and that way, because its object is in the mind, which does not affect the senses when it is collected within itself.
Chap. CXI.—Effect of the Mind upon the Motions of the Body, occasioned by some outward Object.
When the motion is produced by the presence of some object, either the cause is immediate or not. If it be immediate, the figure will first turn towards it the organs most necessary, the eyes; leaving its feet in the same place; and will only move the thighs, hips, and knees a little towards the same side, to which the eyes are directed.
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
