[Footnote: _uno piccolo spiracelo nel mezzo_. M. RAVAISSON, in his edition of MS. A (Paris), p. 52, reads _nel muro_--evidently a mistake for _nel mezzo_ which is quite plainly written; and he translates it _"fait lui une petite ouverture dans le mur,"_ adding in a note: _"les mots 'dans le mur' paraissent etre de trop. Leonardo a du les ecrire par distraction"_ But _'nel mezzo'_ is clearly legible even on the photograph facsimile given by Ravaisson himself, and the objection he raises disappears at once. It is not always wise or safe to try to prove our author's absence of mind or inadvertence by apparent difficulties in the sense or connection of the text.] 526. TO DRAW A FIGURE ON A WALL 12 BRACCIA HIGH WHICH SHALL LOOK 24 BRACCIA HIGH. If you wish to draw a figure or any other object to look 24 braccia high you must do it in this way. First, on the surface _m r_ draw half the man you wish to represent; then the other half; then put on the vault _m n_ [the rest of] the figure spoken of above; first set out the vertical plane on the floor of a room of the same shape as the wall with the coved part on which you are to paint your figure. Then, behind it, draw a figure set out in profile of whatever size you please, and draw lines from it to the point _f_ and, as these lines cut _m n_ on the vertical plane, so will the figure come on the wall, of which the vertical plane gives a likeness, and you will have all the [relative] heights and prominences of the figure. And the breadth or thickness which are on the upright wall _m n_ are to be drawn in their proper form, since, as the wall recedes the figure will be foreshortened by itself; but [that part of] the figure which goes into the cove you must foreshorten, as if it were standing upright; this diminution you must set out on a flat floor and there must stand the figure which is to be transferred from the vertical plane _r n_[Footnote 17: _che leverai dalla pariete r n_. The letters refer to the larger sketch, No. 3 on Pl. XXXI.] in its real size and reduce it once more on a vertical plane; and this will be a good method [Footnote 18: Leonardo here says nothing as to how the image foreshortened by perspective and thus produced on the vertical plane is to be transferred to the wall; but from what is said in Nos. 525 and 523 we may conclude that he was familiar with the process of casting the enlarged shadow of a squaring net on the surface of a wall to guide him in drawing the figure. _Pariete di rilieuo; "sur une parai en relief"_ (RAVAISSON). _"Auf einer Schnittlinie zum Aufrichten"_ (LUDWIG). The explanation of this puzzling expression must be sought in No. 545, lines 15-17.]. [Footnote: See Pl. XXXI. 3. The second sketch, which in the plate is incomplete, is here reproduced and completed from the original to illustrate the text. In the original the larger diagram is placed between lines 5 and 6.