Rules and Examples of Perspective proper for Painters and Architects, etc. / In English and Latin: Containing a most easie and expeditious method to delineate in perspective all designs relating to architecture

by Andrea Pozzo

Here you’ll find the Advantage of your folded Paper; for, applying it to the Line of the Plan, you readily mark the Points 1, 2, 3, 4, 5, 6, of the visual Lines, which must be drawn to the Point of Sight O. Then folding the Paper cross-wise, as in P, you mark the Points 7, 8, 9, 10, placing the Point 7 on that of 6, unless you would have the Square removed within the Line of the Plan. Then from 8, 9, 10, drawing Lines to the Point of Distance E; where they intersect the Line 6, 7, O, draw Parallels to the Line of the Plan; and your Work is done.

Within the Square B, you may easily inscribe another Square, by help of the Diagonals; as may be seen in the Figure.

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Fig. v.

FIGURA QUINTA.

Vestigia quadratorum, cum elevationibus.

Suppositis iis quæ jam diximus de Contractione optica Quadratorum, notandum est, vestigium primi Quadrati distare à linea plani spatio BA opticè contracto; quia linea BD habet à visuali AO, distantiam BA. Eodem modo Quadratum secundum distat à linea plani spatio EA, & sic deinceps.