Vestigium ædificii rotundi opticè imminutum.
Qui sedulam operam in circulis deformandis non posuerint, eosque minimo negotio ex usu describere nequiverint, frustra conabuntur projicere vestigia ædificiorum rotundorum. Ad vitandam confusionem, proderit in vestigio notare primùm lineas occultas membrorum præcipuorum; iisque translatis in elevationem, addere sensim reliquas. Hac industriâ ego ipse in hoc schemate usus sum. Quum autem experimento didicerim summam arduitatem harum descriptionum, aliam regulam adhibere jamdiu cœpi, quam, ut suprà diximus, in aliud Opus reservamus.
The Sixty-fifth FIGURE.
The Plan of a Circular Work in Perspective.
They that have not diligently apply’d themselves to the putting Circles into Perspective, and, by a constant Practice, render’d the Work familiar to them, will in vain attempt that of the Plans of round Buildings. To prevent Confusion, you’ll do well, first to mark the occult Lines of the principal Members; and after those are transferr’d into the Upright, then proceed to the rest, as I myself did in this Figure. But having found by Experience, the great Difficulty of describing these round things, I have long since made use of another Method, which, as I said before, is reserv’d for another Volume.
FIG. LXVI.