For drawing in Perspective a Pedestal, or Base, divided into four Parts, make the Plan A with its Divisions of Length ED, and of Breadth CD; and the same Divisions of Breadth EF, in the Elevation B, prolong’d to X. Then make the Perspective-Plan, by transferring the Breadth and Length into the Ground-line, by means of your Paper folded cross-wise. From which Plan the Perspective-Upright is very easily made, as may be plainly seen in the Figure. How the Base below, without occult Lines, is made from the Perspective-Plan and Upright, is manifest from what has been said before. I could wish you would be very diligent in the Practice of this Method by the Compass; because the Dispatch of Perspective-Delineations chiefly depends thereon.
Fig. 8.
FIGURA OCTAVA.
Optica projectio stylobatæ.
Si libitum fuerit delineare stylobatam, cum projecturis in summo & imo, incipies ab elevatione geometrica A, ducendo occultas ad id necessarias, tum versus perpendicularem L, tum deorsum pro vestigio geometrico B, cujus distantiæ transferentur in spatium G. Si mensuræ longitudinis distent spatio C à mensuris latitudinis, vestigium deformatum videbitur distare à linea K plani, quantum est idem spatium C. In construenda optica elevatione D, visuales ex punctis lineæ L dabunt lineas latitudinis; lineas vero altitudinis accipies ex lineis vestigii contracti, ut in figura. In formando stylobata nitido EF, locum anguli H dabit concursus latitudinis ex linea L usque ad M, & altitudinis ex linea K usque ad I. Concursus tum ejusdem altitudinis, tum latitudinis ex L usque ad O, dabit angulum N. Demum altitudinem anguli P accipies ex K usque ad Q; latitudinem ex L usque ad R.